Yearbook of Anesthesiology 11 Baljith Singh, Mukul Chandra Kapoor
INDEX
Page numbers followed by b refer to box, f refer to figure, fc refer to flowchart, and t refer to table.
A
Abdominal wall, tumor of 271
Abortion, recurrent spontaneous 309
Absorption atelectasis 31
Accident, cerebrovascular 37
Acetylcholine 167
Acid-base balance 258
Acidosis 9, 71, 97
Activated partial thromboplastin time 45, 51, 256
Acute coronary syndrome 46, 62
Acute respiratory distress syndrome 102, 142, 143
Adenosine triphosphate 192
Adrenalectomy 266
partial 266
Adrenaline 284, 325
Adult respiratory distress syndrome 159
Advanced life support 281, 284
Aerosol generating procedures 226, 323
Aggression 296
Airway 154
assessment 5, 21
MACOCHA score for 6t
computed tomography scan 3
management of 1, 10, 21, 24, 284, 319, 326
pressure 143, 144, 268
surgery 19
Alcohol 185
abuse 170
All India Difficult Airway Association guidelines 12
Alpha 2 adrenergic receptor agonists 173
Alprazolam 327
Alveolar collapse 31
Alveolar interstitial syndrome 159
Alzheimer's disease 184, 191
Ambulatory spinal anesthesia, advantages of 223
American Cancer Society Guidelines 251
American College of Cardiology 60
American College of Critical Care Medicine 168
American College of Obstetrics and Gynecology 241
American College of Surgeons National Surgical Quality Improvement Program 65
American Heart Association 60, 96, 329
American Psychiatric Association 164
American Society of Anesthesiologists 203, 252
and Anesthesia Patient Safety Foundation 322
American Society of Anesthesiology 12
American Society of Hematology 311
American Society of Regional Anesthesia 53
Amide 223
Amino acids 167
Aminoglycosides 327
Amiodarone 45, 327
Analgesia 258
balanced 300
epidural 133, 134
regional 137
Analgesics 167, 325
Anaphylaxis 285
Anemia 60
Anesthesia 181, 195, 203, 246, 319, 339
cardiothoracic 111
central neuraxial 68
choice of 68
conduct of 25, 294, 325
deciding scope of 359
drugs 325
epidural 225
general 26, 68, 125, 188, 217, 219, 252, 300, 329
induction of 25
machine 337
monitoring 253f
depth of 214
neuraxial 237, 329
opioid-free 299, 300, 299, 303
public perception of 360
regional 111, 112, 115, 125, 126, 127t, 128, 129t, 136, 219, 225t, 327
role of 187
technique 240
Anesthesiology 336, 353b
Anesthetic agents 91
neural tissue absorption of 187
Anesthetic implications 235, 265
Anesthetic technique 91
regardless of 240
Anesthetists 319, 333
Anger 296
Angina 37
Angiotensin receptor blocker 64, 67, 70
Angiotensin-converting enzyme inhibitor 64, 67, 70
Anterior cruciate ligament 219
Anterior cutaneous branch
block techniques 116
lateral division of 113f
medial division of 113f
Antiarrhythmic 325, 327
drugs, regarding use of 284
Antibiotics 167, 258, 325, 327
antitumor 249
Anticholinergic 189, 293
use 185
Anticholinesterases 173
Anticoagulation 44
Anticonvulsants 167
Antidepressants 327
Antiemetics 325
Antifungals 327
Antihistamines 167
first-generation 189
Antimetabolite 249
Antinauseants 167
Antipsychotics 189, 296
atypical 172
typical 172
Antispasmodics 167, 189
Anxiety 296
Aorta, resuscitative endovascular balloon occlusion of 236
Apixaban 43, 44, 46, 47, 50, 52, 53
Apnea syndrome 6
Apneic oxygenation 1, 8, 9, 19, 30
Appendicectomy 132
Appetite 296
Arrhythmias, development of 290
Arterial blood
gas 258
sampling 255
Arterial cannulation 252
Arterial pressure waveform analysis 252
Arterial pulse pressure variation 252
Artery balloon inflation 236
Articaine 223
Artificial intelligence 1, 2, 5, 12
Asian sudden cardiac death 58
Astrocytes 192
Atelectotrauma 142
Atherosclerotic plaques 186
Atrial fibrillation 60, 62, 290
Atrial natriuretic peptide 101
Atrioventricular block 290
Atropine 325
Auditory verbal learning test 184
Auriculotemporal nerve 129
Automated cuff pressure regulator 12
Automated external defibrillator 283
Awakening and breathing controlled trial 172
Axillary blood vessels 119f
Axillary thoracotomy 115
Azithromycin 327
B
Bag valve mask 8
Barbiturates 167, 293
Barotrauma 142
Basic life support 281, 283
Beer-Lambert law 211
Behavioral pain scale 171
Benzodiazepines 167, 174, 189, 293
Benztropine 167
Beta-blockers 167
Betadine 90
Betrixaban 43, 46, 47, 53
Bhang 288
Bidirectional therapy 260
Biopsy 154
Bispectral index 204, 205
Black box data, use of 344
Blood
brain barrier 174, 186
loss, visual estimation of 230
pressure 8
urea nitrogen 170
Body
mass index 251
tissues 152f
Brachial plexus block 128, 130
Bradycardia, severe 303
Brain 203
derived neurotrophic factor 193
function
intraoperative monitoring of 203
monitoring 203, 204, 205fc, 213, 214
natriuretic
peptide 60, 62
polypeptide 62
nicotinamide adenine dinucleotide phosphate 192
stem 206
Brainstem auditory evoked potential 205, 207
Branchial cyst, excision of 129
Breast 51
Breathlessness 160f
Bronchial tone 290
Bronchodilators 325
Bronchoscopy 51
Bullous emphysema 290
Bupivacaine 127, 220, 221, 223
Buprenorphine 327
Burst suppression ratio 204
C
Calcium 325
Canada Study of Health and Aging Frailty Index 37
Cancer 256
burden of 246
recurrence 303
Cannabinoid
exogenous 289
receptors 289, 290, 290t
Cannabis 288, 289, 294, 297
hyperemesis syndrome 295
indica 289
onset of effect of 292t
pharmacodynamics of 289
sativa 289
user
anesthetic concerns in 292
types of 289
withdrawal syndrome 295, 296t
Caprini score 308, 309, 310t
Carbamazepine 45
Carbon dioxide 267, 328
Carboplatin 249
Carboxyhemoglobin 290
Cardiac arrest 280
epidemiology of 281
Cardiac implantable electronic devices 90, 97
function of 69
intraoperative management of 69
Cardiac index 252, 254, 257
Cardiac medications 167
Cardiac output 83, 257
monitoring 253f
Cardiac resynchronization therapy 64
Cardiac surgery 111, 186, 215, 312, 313
association of 181
Cardiopulmonary bypass 182, 204
Cardiothoracic surgery
analgesia for 111
anesthesia for 111
surgical incisions for 114
Cardiovascular life support, advanced 80
Carotid endarterectomy 214
Catheter
connector 131f
insertion 131f
Caudal analgesia 132, 134
Caudal block 132, 133f
Cell activation 186
Central anticholinergic effects 189
Central nervous system 167, 191, 293
effects 291
pathology 166
Central venous pressure 68, 107, 252
Cerebral
blood flow 207
monitoring 208
velocity 209
circulation 186
hypoxia 189
metabolism 204
microdialysis 213
oximeters 211
oxygenation 210, 211
monitoring of 210
perfusion pressure 211
state monitor 204
vasodilation 270
Cerebrospinal fluid 191
Cervical
plexus block 129
spine limitation 6
surgery, anterior 129
Cesarean hysterectomy 229, 235
Charas 288
Charlson comorbidity index 185
Chemotherapeutic drug toxicities 245
Chemotherapy 249
intraperitoneal 260
Chest
movement 28
radiograph 63
wall 154
fascial blocks of 122
X-rays 63
Chills 296
Chloroprocaine 219, 220, 222, 223
Cholecystectomy 50, 132
Choledocoduodenostomy 132
Chemotherapy, regional heated 245
Chorionic villi invade myometrium 230
Chronic hyponatremia reverses cognitive dysfunction 190
Chronic obstructive pulmonary disease 37, 60, 267, 290
Circle of Willis 272
Cisplatin 249
Clamshell thoracotomy 114
Clarithromycin 45
Classical phenotype method 36
Cleft
lip 129
palate 129
Clinical frailty scale 37
Clinical impairment assessment score 185
Clonidine 127, 173
Clotting time 239
Coagulation 258
parameters 253
Cognitive dysfunction 181, 182, 185, 187, 194
Cognitive impairment 170, 189
Colloids 325
Coma 6
Communication 353
Compartment syndrome 267
Complete apnea for tubeless technique 30
Comprehensive complication index 254
Computed tomography scan 2, 3, 63, 205, 358
Confusion 184
assessment method 168, 184
Consciousness, acute disturbance in 164
Consolidation 157
Continuous flow 79
output 83
Continuous infusion 127
Cords, posterior third of 26
Corneal injury 270
Coronary angiography 188, 285
Coronary artery
bypass graft 186
disease 60, 290
surgery 182
Coronary spasm 290
Coronavirus disease 2019 (COVID-19) 226, 282, 319, 323, 329
anesthesia leadership during 360
crisis 299
disease 328, 329
guidelines, development of 280
infection 281, 321, 323, 324, 326, 328, 329, 332
intensive care of 319
pandemic 14, 217, 226, 319, 351, 361
symptoms 324
Corticosteroids 189, 293
use 170
Cough, excessive 328
Cranial disease 270
Cranial nerve 204
monitoring 208
Craniopharyngiomas 207
Craniotomy, frontal 129
Cricothyrotomy
percutaneous 13
surgical 13
Critical-care pain observation tool 171
Crystalloids 325
Custom-built transnasal oxygen cannula 31f
Cystectomy 266, 309
Cystic artery 338
Cystic duct 338
Cytology 154
Cytoreductive surgery 245, 246, 257, 259, 261
anesthetic management of 245
D
Dabigatran 44, 45, 52, 53
etexilate mesylate 45
inhibits 43
Daily living, activities of 182
Deep vein thrombosis 48, 257, 308
prophylaxis 259
Delirium 163, 165, 165t, 167b, 174t, 177, 184, 189, 293
causes of 166t
chronic 166
management of 170
pathophysiology of 166
persistent 166
phenotypes 164
postoperative 182, 184, 185, 217
prevalence of 168
subsyndromal 165
tremens 166
Delta 9-tetrahydrocannabinol 289
Dementia 37
grading of 184t
Depressed mood 296
Destination therapy 82
Dexamethasone 127, 327
Dexmedetomidine 127, 173, 303
Diabetes mellitus 60
Diaphragm 143
Diazepam 327
Diclofenac 327
Difficult airway
assessment 5
management guidelines 5
Difficult Airway Society 9
Digitalis 167
Diltiazem 327
Dilute thrombin time 51
Dimenhydrinate 167
Direct brain tissue oxygen monitoring 210
Direct-acting oral anticoagulants 43, 44, 49, 48t, 49t, 51t, 52, 313
Docetaxel 250
Dopamine 167
antagonists 172
Dorsal rami 116
blocks 120
lateral cutaneous branch of 113f
medial cutaneous branch of 113f
Doxorubicin 249
Drugs 166, 167
interactions 293t
safety 345
Duke activity status index 66
Dutch prospective cohort study 59, 343
Dyselectrolytemia 245, 258
Dyspnea 328
E
Ear surgery 129
Eastern Cooperative Oncology Group 251
Edema, pulmonary 324
Edmonton frail scale 38
Edoxaban 43, 44, 46, 47, 52, 53
Ejection fraction 60, 63, 70
Electrocardiogram 63, 252
Electroencephalography 204, 205
Electrolyte disturbances 255
Electromagnetic interference 90
Electrophysiologic procedures 51
Electrophysiology monitoring 204
Embolism, pulmonary 43, 48, 62, 285, 308
Embolization 186, 236
Emergency transtracheal airway catheter 13
Emotional intelligence 353
End-diastolic velocity 209
End-expiratory pressure 8
Endocannabinoid system 288, 289
Endocrinopathy 166
Endoscope 13
Endoscopic sinus surgery 129
Endothelial glycocalyx 100, 101
Endothelial injury, biomarker of 192
Endotracheal tube 1, 10, 11, 71, 257, 326
placement, artificial intelligence-assisted 12
End-tidal carbon dioxide 8
Enhanced recovery after surgery 104, 112, 217, 225, 273, 300
Entropy 206
Epidemiology 281
Epidural catheter 131f
Epidural kit pediatric 131f
Epiglottis, laryngeal surface of 25f
Epinephrine 241, 284
Erector spinae 121f
muscle 113f, 121f
plane block 113f, 120, 122, 131f
Esophagectomy 103
European Registry of Cardiac Arrest 282
European Resuscitation Guidelines 280
European Society of Cardiology Heart Failure Long-Term Registry 58
European Society of Intensive Care Medicine 286
Evoked potential monitoring 206
Exercise tolerance, measurement of 66
Extracorporeal membrane oxygenation 82
Extravascular lung water 159
F
Face recognition technology 2
Facial
hair 21
nerve 208
Factor Xa inhibitors 45
Fascia iliaca 135
Fascial plane 117f, 119f
blocks 125, 127
produce analgesia 116
Favipiravir 327
Fentanyl 127, 327
Fever 296
Fiberless videoendoscope 1
Flexible intubation video endoscope 13
Flexible nasal laryngoscopy 22f
Flow waveforms 94
Fluid
administration 100, 102
choice of 105
management 100, 101, 103
therapy 245, 253
Fluoroquinolones 167
Focused transthoracic echocardiography 154
Food and Drug Administration 45, 81
Formal cardiopulmonary exercise testing 66
Fraction of inspired oxygen 148
Fractures 135
Frail scale 38
Frailty 3436, 40
assessment of 34, 35
index 36
Frank-Starling principle 88, 89
French-Language Society of Pediatric Anesthesia 136
Fresh frozen plasma 238, 258
Fried phenotype method 35
Front-of-neck airway access 2, 13
Functional residual capacity 250
G
G6PD deficiency 327
Gait speed 39
Gamma-aminobutyric acid 167, 188, 194
receptor
role of 194
theory 181, 194fc
Ganja 288
Gastric cancer 250
Gastroesophageal reflux disease 23
Gastrointestinal
agents 167
anastomosis 247
bleeding 45
Geriatric depression score 184
Glial fibrillary acidic protein 205
Glidescope, development of 10
Global brain dysfunction 164
Glomerular filtration rate 275
Glycemic control 259
Goal-directed fluid therapy 107, 253, 254fc
Gosling index 209
Greater occipital nerve 129
Greater palatine nerve 129
Grip strength 35
Gynecological robotic laparoscopic surgery 265
H
H2-receptor antagonists 189
Haloperidol 172
Head and neck, surgery in 128
Headache 296
cervicogenic 129
Healthcare system 350
Hearing impairment 185
Heart failure 5760, 64fc, 70, 73, 80, 327
ambulant 58t
chronic 59
clinical presentation of 61
congestive 37, 65
diagnosis of 61, 62fc
end-stage 79
etiology of 72
evaluation for 61
hospitalizations 58
management of 63, 71
registry 58
Society of America 72
status of 72
with mid-range ejection fraction 60
with reduced ejection fraction 60
Heated chemotherapy infusion 253f
Heavy metals 166
Hemodynamic
fluctuations 245
instability 103
monitoring 252
Hemoglobin, deoxygenated 211
Hemorrhage, diffuse alveolar 290
Hemorrhoids 51
Heparin 325
unfractionated 312
Hernia 51
repair 266
Herniotomy 132
High clinical frailty score 185
High-flow nasal cannula 15
High-intensity signals 214
High-mobility group box-1 chromatin protein 191
High-quality chest compressions 284
Hip and knee arthroplasty 309
Hoarseness 21
Hormone replacement therapy 309
Human papilloma virus 23
Humidified oxygen 33
Hunsaker tube 29, 29f
Hydrocortisone 325, 327
Hydropneumothorax 160f
Hydroxychloroquine 327
Hydroxyzine 167
Hyoid bone 2
Hyperactive delirium 164
Hyperalgesia, opioids-induced 300
Hyperbaric
bupivacaine 127
prilocaine 219
Hypercapnia 9, 268, 269
Hypercarbia 9, 30, 71, 97, 265
Hyperchloremia 106
Hyperchloremic acidosis 106
Hyperglycemia 250, 255
transient 255
Hyperkalemia 9, 106, 285
Hyperlactatemia 250
Hypernatremia 185, 190
Hypertension 7, 37, 60, 166
pulmonary 9, 62
Hyperthermia 185, 255, 285
Hyperthermic intraperitoneal chemotherapy 245247, 254, 259
Hyperthermic thoracic chemotherapy 261
Hyperthermic thoracoabdominal chemotherapy 261
Hypoactive delirium 164
Hypocalcemia 250
Hypokalemia 285
Hypokinesia 324
Hypomagnesemia 250, 255
Hyponatremia 185, 255
Hypophysectomy, trans-sphenoidal 129
Hypotension 71, 166, 189
intraoperative 189
management of 93
Hypothermia 71, 97, 185, 190, 256, 285
Hypovolemia 189
neonatal 235
Hypoxemia 6, 7, 97, 265
Hypoxia 62, 71, 166, 285
Hypoxic pulmonary vasoconstriction 8
Hysterectomy 50, 234
peripartum 230, 241
I
Idiopathic dilated cardiomyopathy 60
Iliacus muscle 135
Immunization 73
Implantable cardioverter defibrillators 64, 69, 79, 87
Incision
longitudinal extent of 122
site of 122
Inducible nitric oxide synthase 166
Infection 166
Inferior vena cava 252
Inflammation 166
Infraorbital nerve 129
Inhalational anesthetic agents 325
In-hospital cardiac arrest 282
Inner intercostal muscle 113f
Inotropes 100, 325
Insulin-dependent diabetes mellitus 65
Intensive care
delirium screening checklist 168, 169
unit 3, 5, 163, 259
Interagency Registry for Mechanically Assisted Circulation 81
Intercostal muscle 113f, 117f
Intercostal nerve blocks 112, 115
Internal oblique muscle 134, 135
Internal thoracic blood vessels 113f, 114
International congestive heart failure 58
International Society for Heart and Lung Transplantation 81
International Society on Thrombosis and Hemostasis 44
Interventricular septum 89
Intracranial biochemistry 213
monitoring 204
Intracranial hemodynamics 204
Intracranial pressure 8, 205, 211, 265, 270, 271
monitoring 211
Intracranial procedure 208
Intralipid 325
Intraocular pressure 265, 270
Intraoperative fluid management 106
Intraperitoneal hyperthermic chemotherapy 245, 257, 261
Intrapleural pressure 145
Intrathoracic pressure 107, 270
Intravenous technique 25
Intubation
box 14
esophageal 337
Invasive neurosurgical procedures 309
Irinotecan 250
Irritability 296
Ischemic heart disease 65
Isobaric bupivacaine 127
Ivermectin 327
J
Jet ventilation 19, 27
Jugular venous
oximetry 210
pressure 62
K
Ketamine 295
metabolism of 327
sequence intubation 9
Ketoconazole 45
Ketorolac 327
Kidney
disease, chronic 160f
dysfunction 327
injury, acute 105, 250, 259
Knee arthroscopy 219
L
Lambert laws 211
Laminectomy 52
Laparoscopic
nephrectomy 274, 275
varicocelectomy 266
Laparoscopy 321
Large intra-abdominal mass 271
Laryngeal
mask airways 12
nerve, recurrent 208
pathology 23
surgery 19
Larynx 20
Laser surgery 24
Lateral cutaneous branch
anterior division of 113f
block techniques 117
posterior division of 113f
Latissimus dorsi muscle 112, 113f, 118f
Leadership
development methods 355
fundamental principles of 353
Left ventricular
assist device 79, 80
dysfunction, categorization of 60t
Levobupivacaine 127, 221, 223
Lidocaine 220, 223
Lignocaine 220, 221, 327
Lithium 167
Liver dysfunction 250
Local anesthetics 127t, 218
agents 325
distribution of 125
Local infiltration analgesia 128
Low molecular weight heparin 48, 49, 312
Low-cost interventions 343
Lower limb
blocks 127
surgery 134
Lower lip surgery 129
Low-flow oxygen 30
Low-lying placenta 229
Lumbar epidural anesthesia 225
Lung 154
fluid-like behavior of 145
injury 102, 142, 146, 147
acute 102
causes of 146
following thoracic surgery 102
parenchyma, ultrasound appearance of 156f
sliding sign 151, 155
ultrasonography 150, 153, 159
volume 147
Lymph node 129
dissection 309
M
M mode ultrasonography 160f
Macrolides 327
Magnetic resonance imaging 2, 3, 63, 205
Major adverse cardiac event 57, 65
Major neurocognitive disorder 183
Major vascular procedures 309
Mallampati classification 3, 21
Mallampati score 6
Manual aortic compression 236
Manual jet ventilation 27
Massive blood loss 238
Massive transfusion protocol 238
Matrix metallopeptidase 205
Mean arterial pressure 211, 238, 257, 258, 269, 286
Mean flow velocity 209
Mechanical circulatory support 64, 79, 80
Mediastinal mass lesion, anterior 159f
Medical emergency team 284
Medical leadership competency framework 355
Melker surgical cricothyrotomy set 13, 14
Mental fatigue 330
Meperidine 189
Mepivacaine 223
Mesotheliomas 246
Metabolic acidosis, severe 7
Methadone 327
Methotrexate 236
Methyldopa 167
Metoclopramide 189
Microlaryngeal tube 26f
Micro-transducer invasive techniques 212
Microtubule inhibitor 250
Midazolam 327
Middle cerebral artery 209
Midline dermoid excision 129
Mid-thoracic wall, cross-section of 113f
Migraine 129
Mild neurocognitive disorder 183
Mini-mental state examination 184
Mitomycin C 249
Modern classification system 72
Modified frailty index 36
Modified rapid-sequence intubation 9
Monitored anesthesia care 15, 359
Morbidly adherent placenta 230
Morphine 127, 327
Motor cortex 207
Motor evoked potential 207, 208
Multiple neuropsychological testing 183
Multiple trauma 309
Multisystem disease 57, 59
Multisystem inflammatory syndrome 324
Muscle
external intercostal 113f
relaxants 294
Myelosuppression, pulmonary toxicity 250
Myocardial infarction 37, 115
Myocardial injury after noncardiac surgery 69, 70
management of 70fc
Myocardium 96
Myosin targets 72
N
Naltrexone 327
Narcotic Drugs and Psychotropic Substances Act 289
Nasal septal surgery 129
Nausea, postoperative 217, 220, 224, 227, 302
National Center for Healthcare Leadership's Health Leadership Competency 355
Near-infrared spectroscopy 210, 214
Neck
dissection 51
masses 21
MRI 3
soft tissue, anterior 4
X-ray 2
Necrotizing bronchiolitis 290
Needle cricothyrotomy 13
Nephrectomy 265, 266
partial 266, 275
Nephropexy 266
Nephrotoxic drugs 327
Nerve
block kit 135f
injury 253
positioning 270
Neural tissue 192
Neuroinflammation 191, 193fc
Neuroleptic malignant syndrome 173
Neurologic surgery 312, 314
Neuromuscular blocker 8
Neuronal apoptosis 192
Neuropsychiatric syndrome 163
Neurosurgery 51
Neurotoxic effects 189
Neurotransmitters 167
New York Heart Association 60
Nitroprusside 71
Nitrous oxide 24
Nociceptive stimuli 114
Nomenclature 182
Noncardiac disorders 62
Noncardiac surgery 57, 58
perioperative management for 64
procedures 79, 81
Noninvasive blood pressure 252
cuff and pulse oximetry 89
Noninvasive cardiac output monitoring 269
Noninvasive positive pressure ventilation 2, 8
Noninvasive techniques 212
Nonrebreather mask 8
Nonsteroidal anti-inflammatory drugs 167, 253, 325
Nonvalvular atrial fibrillation 43, 48
Norepinephrine 71, 167
Nosocomial infections, prevention of 161
Nursing delirium screen scale 184
Nutrition 259
Nutritional assessment 251
O
Obesity 60, 315
Obstetric
anesthesia 229
hemorrhage, management of 238
management 233
Occipital neuralgia 129
Off-pump coronary artery bypass graft 186
Olanzapine 173
Oliguria 105
Omeprazole 327
Ommaya reservoir placement 129
Oncologic procedures 309
Ondansetron 327
On-pump coronary artery bypass graft 186
Open cardiac surgery 51
Operation
extensive abdominal 271
theater 325t
drug safety in 345
equipment for 325b
Opioids 111, 224, 293, 295, 299, 300, 303, 325, 327
Optic nerve 207
sheath diameter 212
Optiflow high-flow humidified oxygen delivery system 31f
Oral absorption 45
Oral contraceptives 309
Orchidopexy 132
Orthopedic
procedures 313
surgery 215, 311, 313
Orthopnea 328
Orthotopic liver transplant surgery 214
Out-of-hospital cardiac arrest 282
Ovarian 250
cancer 250
Oxaliplatin 249
Oxidative stress 191, 192, 193fc
Oxycodone 327
Oxygen
delivery 256
humidification unit 31f
partial pressure of 143
saturation 8
measurement of 210
P
P wave 137
Packed red blood cells 238
Paclitaxel 250
Pain
abdominal 296
chronic 112
management 97, 253
perioperative 295
related cognitive dysfunction 190
surgical 301
Pan endoscopy 25
Pandemic on anesthesia personnel, effect of 330
Paracetamol 253, 325
Paralysis 144
Parapneumonic effusion 159f
Parathyroid 214
Parkinson disease 173
Partial thromboplastin time 88
Patient state index 204, 206
Peak systolic velocity 209
Pecto-intercostal plane block 113f, 117f
Pectoral nerve block 132
target plane 113f
Pectoralis major 113f, 117f, 119f
muscles 114
Pectoralis minor 113f, 119f
muscles 119f
Pediatric
life support 281
neurosurgical and craniofacial procedures, regional anesthesia for 129t
regional anesthesia network 136
Pericardial disease 62
Pericardial tamponade 285
Perioperative acute heart failure and hypotension 70
Perioperative neurocognitive disorder 182, 186
Perioperative neurological dysfunction 181, 183t, 189
Perioperative venous thromboembolism 308
prevention 307
Peripheral nerve 206, 207
blocks 126, 154, 225, 328
Peripheral vascular disease 37
Peripheral vision 330
Peritoneal carcinomatosis index 248f
Peritoneal surface
malignancies 245
oncology group international criteria 247, 248b
Persistent postoperative opioid use 300
Persistent post-thoracotomy pain 112
Personal protective equipment 281, 320, 322
Pertrach emergency cricothyrotomy kit 13
P-glycoprotein inhibition 53
Pharmacokinetics 47t, 291
Pharmacoprophylaxis 314
Phenothiazine-type antiemetics 189
Phenylephrine 241
Pheochromocytoma, extra-adrenal 266
Physical frailty phenotype 35
Physiotherapy 259
Phytocannabinoids 288
Piezoelectric crystal arrangement 152
Placenta
accreta 237
spectrum disorders 229, 230
vera 230
increta 230
percreta 230
previa 229, 233, 241
Plant alkaloid 250
Plateau pressure 145
Platelet function analysis 88
Platinum analogs 249
Pleura, ultrasound appearance of 156f
Pleural effusion 157, 324
Pleural fluid aspiration 154
Pleural pressure 143
Pneumonectomy 102
Pneumonia 37, 324
bacterial 159f
Pneumoperitoneum 265, 267, 268, 321
Pneumothorax 151, 158, 160f
Point-of-care
testing 88
ultrasound 285
Polyneuropathy 250
Polypectomy 51
Polyurethane 126
Polyvinylchloride 14
Positive end-expiratory pressure 144
Postanesthesia care unit 224, 273
Postdural puncture headache 219
Posterior fossa surgery 129
Post-intensive care syndrome 177
Postoperative cognitive dysfunction 182, 183, 184t, 188
Post-resuscitation care 281, 286
Potassium 325
Pourcelot index 209
Povidone iodine 90
Powered air-purifying respirator 322
Pre-existing neurocognitive disorder 182
Pregnancy 309
Prehabilitation 251
Premature birth 309
Preoperative fine nasal fiberoptic endoscopic examination 22
Preoxygenation 6, 326
Pressurized intraperitoneal aerosol chemotherapy 260
Prilocaine 220, 222, 223
Propofol 174, 293, 327
Prostate, transurethral resection of 312
Prothrombin
complex concentrate 239
time 45, 51, 88, 238, 256
Proximal humerus surgeries 128
Proxy paravertebral blocks 120
targets for 113f
Pruritus 217
Pseudomyxoma peritonei 246, 250
Pulmonary artery pressure monitoring 252
Pulsatility index 87, 209
Pulse
index 92, 95
pressure variation 68
Pump
flow 92, 93, 95
output 87
power 92, 93, 95
speed 92, 93, 95
Pyeloplasty 266
Q
QRS complex 137
Quantitative methods 238
Quetiapine 173
Quinolones 327
R
Racemic ketamine 127
Radical
cystectomy 265, 266
prostatectomy 265, 266, 309
Raised intracranial pressure 9
Randomized controlled trial 177, 186
Ranitidine 327
Rapid-sequence induction intubation 8, 326
Ravussin cannula 30
Reconstructive procedures 310t
Regional wall motion abnormalities 324
Remdesivir 327
Remote robot-assisted intubation system 16
Renal failure 53, 62
Renal injury 275
Renal pelvis 266
Resistance
index 209
syringe, loss of 131f
Respiratory failure 170
Respiratory system 258
Restrictive fluid management 105
Resuscitation 80, 319, 325, 329, 356
drugs 325
cardiopulmonary 280, 330
Retrolaminar block 113f, 120, 121f
Retroperitoneal surgery 134
Reverse transcriptase-polymerase chain reaction 323
Revised cardiac risk index 65, 65t
Rhabdomyolysis 267
Rhomboid intercostal sub-serratus plane block 119
Rhomboid major 121f
muscle 113f
Richmond agitation sedation scale 168
Rifampicin 45
Right ventricular
dilatation 324
dysfunction 71
failure 7
Rigid bronchoscopy 32
Ringer's lactate solution 105
Risperidone 173
Rivaroxaban 44, 46, 47, 48, 50, 52, 53, 65
Robotic
assisted partial nephrectomy 275
assisted radical
cystectomy 273
prostatectomy 271
endoscope 16
intubation 16
laparoscopic surgery 266
partial nephrectomy 275
radical prostatectomy 265
urological surgeries 265, 267, 271, 276
Ropivacaine 127, 220, 222, 223
Rotational thromboelastometry 88, 238, 239
ROTEM-guided goal directed therapy 239fc
S
Sacral cornu 133f
Sacrococcygeal ligament 133f
Sarcopenia 39
Scalp
nevus excision 129
temporoparietal incision of 129
Scopolamine 167
Sedation
daily interruption of 172
lesser use of 144
protocols 172
scoring 172
Seldinger's technique 210
Sensory impairment 185
Sepsis 8, 166, 285
Serotonin 167
Serratus anterior muscle 112, 117, 119f
Serratus anterior plane block 120
ultrasound image for 118f
Severe acute respiratory
disease syndrome 142
syndrome coronavirus 2 323
Severe local anesthetic systemic toxicity 136
Severe obstructive sleep apnea 3
Sevoflurane 327
Shock 69
critical cardiogenic 82
hypovolemic 271
Shoulder 128
Sickle cell disease 271
Simulators, use of 344
Skeletal muscle relaxants 167, 189
Skin surface surgeries 51
Sleep apnea 62
Sliding sign 155
Small renal masses 275
Society of Critical Care Medicine 168
Sodium bicarbonate 325
Somatosensory evoked potential 207
Spinal anesthesia 127, 136, 217219, 224226
Spinal cord 206
Spontaneous breathing 143145
effect of 142
mechanism of 143
trial 172
Spontaneous respiration 142, 146
induced lung injury, management of 147
Starling's mechanism 91
Starling's principle 101
Steep head-down tilt 265, 266
Stem cell therapy 72
Sternomastoid tumors 129
Sternum 113f
Steroids 167
Stress
surgical 186
ulcer prophylaxis 259
Stroke
prevention 48
volume 257
variation 68, 252, 254
Subtransverse process interligamentary block 113f, 121
Sufentanil 127, 327
Sugarbaker peritoneal carcinomatosis/cancer index 248
Superficial anterior cutaneous branch block 113f
Superficial cervical plexus 129
Superficial lateral cutaneous branch block, target plane for 113f
Superficial serratus anterior plane block 113f
Superior costotransverse ligament 114
Supraclavicular nerves 114
Supraglottic airway device 1, 9, 12
Supraglottic jet ventilation 28
Supraorbital nerve 129
Supratrochlear nerve 129
Surgery 181, 195
abdominal 132
ambulatory 217, 218, 225, 226
anesthesia for 19, 20
esophageal 214
general 311, 312
timing of 321
Surgical airway, newer devices in 13t
Sweating 296
Swedish dementia quality registry 188
Synaptic network breakdown 192
Systemic inflammatory response 186
Systemic vascular resistance 252
T
Tachycardia 293
Tandem mass spectrometry 51
Temperature
management 256
regulation 291
Tension pneumothorax 285
Teres major 118f
Tetrafluoroethylene 14
Thermal chemotherapy 253
Thiamine 166
Third-generation continuous flow centrifugal pump 84f
Thoracic
anesthesia 101
fluid management for 100
epidural
analgesia 114
anesthesia 115
paravertebral block 115, 120
spinal nerves, ventral rami of 112
surgeons 81
surgery 105, 111, 130
fluid in 100
ultrasonography 150, 153f
evolution of 153
Thoracoscopic surgery 132
Thoracotomy 131, 132
anterolateral 114
bilateral anterolateral 114
incision 114
Three-dimensional CT scan 3
Thrombectomy, pulmonary 285
Thrombin time 51
Thromboelastography 88, 238, 256
Thromboembolic disease 267
Thromboembolism 285
prevention of 48
Thrombolysis 285
Thrombophilia 315
Thyroglossal cyst 129
Thyroid 166, 214
surgery 129
Tilburg frailty indicator 35, 38
Timed up-and-go test 39
Tongue
measurements 4
volume 4
Tonometry 212
Topoisomerase inhibitor 250
Total hip replacement 313
Total intravenous anesthesia 19, 252
techniques 25
Total joint replacement 313
Toxemia 309
Toxins 166
Trachea 20
Tracheal deviation 21
Tracheal intubation 1
laryngeal imaging for 16
Tracheostomy 23, 32
percutaneous dilatational 14
Tracoe smart cuff managerTM monitors 12
Tramadol 327
Transabdominal plane block 132
Transcatheter aortic valve replacement 115
Transcranial Doppler 209, 213
basic principle of 209
Transesophageal echocardiography 252, 275
Transglottic jet ventilation 28
Transient ischemic attack 37
Transnasal humidified rapid insufflation ventilatory exchange 9, 31
Transpulmonary pressure 143, 145, 345
Transthoracic echocardiogram 92
Transtracheal jet ventilation 30
Transverse abdominis plane 253
Transversospinalis muscle 114
Transversus abdominis muscle 134
Transversus thoracic muscle 113f
Transversus thoracis plane block 113f, 117
Trapezius 113f
Trauma 285, 356
surgery 312, 314
Traumatic brain injury 8
Tremors 296
Tricyclic antidepressants 167, 293, 296
Trihexyphenidyl 167
Triple P procedure 235
Tubeless anesthesia 19, 20, 26
Tumorigenicity, soluble suppression of 72
Tuohy needle 131f
Tympanic membrane displacement 212
Tympanomastoid surgery 129
U
Ultrasonography 2, 3, 151, 157, 232
display of 152f
Ultrasound 126
examination 154
guided
brachial plexus block 130
fascial plane blocks 115
interventions 154
nerve blocks 111, 122
thoracic interventions 162
probe 161
technique 154
transducer 152
Upper limb
blocks 127
surgeries 128
Ureter percutaneous stone retrieval 266
Ureteric reimplantation surgery 134
Urinary catheterization 252
Urine output 100, 254, 255
Urologic surgery 52, 311, 312
Urological laparoscopic surgery 266
Uterus 233
Uvular edema 290
V
Valvular heart disease 60
Vascular surgery 51, 214
Vasoactive drugs 241
Vasodilators 325
Vasopressors 100, 325
Venous ophthalmo-dynamometry 212
Venous thromboembolism 43, 49, 307, 328
Caprini risk assessment model for 310t
Ventilation 203
failure, complete 9, 10
strategies 26
Ventilator-associated pneumonia 11, 14
Ventrain device 15
Ventral rami 116
anterior cutaneous branch of 113f, 116
blocks 120
lateral cutaneous branch of 113f, 116
Ventricular assist device 98
Ventricular tachycardia 290
Ventriculoperitoneal shunt 129
Verapamil 45
Vertebral body 113f
Video-assisted thoracoscopic surgery 104
Videolaryngoscope 1, 2, 10
classification of 11fc
Visual acuity 330
Visual evoked potential 207
Visual impairment 185
Vital signs, monitoring of 125
Vitamin
B12 166
K antagonist 43, 44, 48t, 49
Vocal cord, midpoint of 4
Vomiting, postoperative 217, 220, 224, 227, 302
W
Warfarin 293, 327
Weight loss 296
World Health Organization 299
X
X-ray 2
×
Chapter Notes

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New Technologies to Secure the AirwayCHAPTER 1

Syed Moied Ahmed,
Manazir Athar

ABSTRACT

Airway management is an essential life-saving skill that has to be mastered by every anesthesiologist. Complications arising from the unanticipated difficult airway or failed tracheal intubation remain a leading cause of anesthetic morbidity and mortality despite recent developments in airway management strategies. Its incidence can vary between 1.5% and 20% depending upon the patient, healthcare personnel, and environmental factors. Identification and management of difficult airways are of paramount importance to improve the outcomes in such situations. Many novel techniques, concepts, and devices have been introduced into clinical practice to reduce the morbidity and mortality associated with difficult airway. This chapter summarizes the role of these technologies in securing the airway.
Keywords: Difficult airway; recent advances; airway imaging; artificial intelligence; apneic oxygenation; video laryngoscopy.  
KEY POINTS
  • Airway management is an essential skill for anesthesiologist.
  • Novel techniques, concepts, and devices have been introduced into clinical practice to reduce the morbidity and mortality associated with difficult airway.
  • Imaging technologies, such as X-ray, computed tomography, magnetic resonance imaging, and ultrasonography, can assist in the difficult airway assessment and prediction.
  • Artificial Intelligence-based technologies have been introduced in airway management.
  • Physiological factors of difficult airway have taken precedence over anatomical factors.
  • Apneic oxygenation, delayed-sequence intubation, cannot-intubate cannot-oxygenate, and complete ventilation failure have important implications in patients of anatomical as well as physiological difficult airway.
  • Several new videolaryngoscopes, endotracheal tubes, supraglottic devices, fiberless videoendoscope, and devices for special scenarios have come into clinical practice.
 
INTRODUCTION
Airway management is an essential skill that an anesthesiologist has to acquire and exercise every day. No wonder it has been the subject of much research and innovation.2
The term difficult airway is a concept well appreciated by airway managers around the world. In its broadest sense, it can be defined as challenges associated with any of the four components of airway management, i.e., face mask ventilation, supraglottic airway insertion, tracheal intubation, and emergency front-of-neck airway (FONA) access.1 It is notable that difficulty with any of these management methods is primarily related to anatomic features that make these techniques procedurally challenging. Thus, as presently understood, the term difficult airway essentially denotes an anatomically difficult airway. Technological advances, such as flexible intubation scopes and rigid videolaryngoscopes (VLs), have substantially improved our ability to manage such cases safely. Recent advances in technology have made laryngoscopy less dependent upon a direct line of sight to achieve tracheal intubation. However, the success and safety of these devices depend on the way they are used.2 In addition, improvements in methods of pre-oxygenation, such as high-flow nasal oxygen and noninvasive positive-pressure ventilation (NIPPV) have allowed a longer duration of apnea without desaturation, allowing more time to manage the airway safely.3 This chapter summarizes some of the recent trends and technologies in airway management.
 
ASSESSMENT METHODS AND TOOLS
Many airway assessment methods such as history, physiopathological factors, individual and group indices, and bedside tests are routinely used, but they have very low sensitivity. So, it is necessary to optimize the prediction process and accuracy. Recently, imaging, artificial intelligence (AI), and face recognition technology as an aid to the assessment of difficult airways are described and are significantly better than the traditional assessment methods.4
 
Imaging Technology in Airway
X-ray, computed tomography (CT), magnetic resonance imaging (MRI), ultrasonography (USG), and other imaging techniques can assist in the assessment and prediction of the difficult airway. However, they also come with many drawbacks, such as radiation exposure, high cost, sophisticated equipment, and medical staff burden, which preclude them from being widely used in clinical practice.
 
Neck X-ray
Skull lateral X-ray shows the bony changes in the airway anatomy, such as linear distance from the mandibular alveolar line to the hyoid bone, from the inner edge of the mandible to the hyoid bone, and from the chin vertex to the attachment of the apex of the lower incisor and the hyoid bone. These imaging indices reflect the tongue enlargement and have been better predictors than the Mallampati classification, with sensitivity and specificity of 0.78 and 0.88, respectively.5 Although X-rays can delineate bony and structural abnormalities in the airway, they cannot be used clinically as a routine tool to evaluate difficult airways, considering its adverse hazards, such as radiation.3
 
Computed Tomography Scan
Airway CT scan with three-dimensional (3D) reconstruction better shows the airway anatomy and its physiological and pathological changes. The airway length is expressed as the vertical distance from the hard palate to the hyoid bone in the median sagittal plane, and the volume is stated as the cross-sectional area from the hard palate to the hyoid bone. It is found that the airway length, but not the volume, is an important variable in the prediction of apnea and hypopnea indices in patients with severe obstructive sleep apnea (OSA). Besides these, age and tongue area are also independent risk factors for difficult laryngoscopy, and when the best-predicted cutoff point of the tongue area is taken as 2,600 mm2, PPV is 37% and NPV is 89%.4 Accuracy of the tongue area to predict difficult laryngoscopy is 65%.
Three-dimensional CT scan: 3D airway CT assists in the construction of a 3D printed model of the patient's airway for evaluation and planning. A good correlation has been shown between predicted nasal intubation difficulty on CT (nasal diameter ≤6.3 mm indicates nasal intubation difficulty) and the actual nasal intubation difficulty.6 The negative predictive value and positive predictive value of CT predicting in nasal intubation difficulty were 90.7% and 71.4%, respectively. 3D CT can be used as an additional evaluation tool for patients with poor airway conditions. However, there are limitations to the routine use of CT for difficult airway assessment, such as radiation risk, medical burden, equipment requirements, human and material resources, and the long operation time and large space requirements.
 
Neck MRI
Magnetic resonance imaging avoids the radiation hazards associated with other imaging technologies, such as CT and X-ray, and has advanced 2D and 3D features to detect structural changes in the soft tissues of the airway. Position of the vocal cords predicts difficult laryngoscopy. The vocal cord in the difficult airway is close to the cranial pyramid, while those in the easy group are located in the fifth cervical spine.7
 
Ultrasonography
With the increasing availability of portable ultrasound, role of USG imaging in airway mangement has been greatly enhanced. It helps in rapid assessment of the airway anatomy in the operation theater, intensive care unit (ICU), 4emergency department, and remote environment. The thickness of the anterior epiglottis, the thickness of the anterior hyoid bone, the thickness of the anterior vocal cord, the thickness of the lateral pharyngeal wall, and the distance from the base of the tongue to the skin have been described in the literature as predictors of the difficult airway. Other indicators include tongue thickness and volume, oral exposure ratio, and hyomental distance ratio (HMDR).
Anterior neck soft tissue: It can be measured at the level of the hyoid bone, epiglottis, cricothyroid membrane, thyroid isthmus, suprasternal notch, and vocal cords. To standardize the measurements, the patient must lie supine and put the head in a neutral position. Generally, a 6–13 MHz high-frequency linear transducer is used for scanning. Neck circumference >50 cm and a soft-tissue thickness >28 mm at the level of vocal cord indicate a difficult laryngoscopy. Other parameters, such as median distance from skin to the epiglottis 25.4–27.5 mm (sensitivity 82%; specificity 91%), epiglottic area 5.04 cm2 (sensitivity 85%; specificity 88%), and thickness of the anterior hyoid bone soft tissue at a cut-off value of 1.28 cm (sensitivity 85.7%, specificity 85.1%), are also found to be significantly related to the difficult airway. Inferior positioning of hyoid bone and the thick pharyngeal wall is found to be associated with an increased risk of OSA. Even though there is plenty of variation in the cutoff value of the anterior cervical soft-tissue thickness at different levels and even at the same level, most studies believe that it is an independent risk factor.
Tongue measurements: Tongue thickness, cross-sectional area, tongue volume, and its ratio to oral cavity volume are found to be predictors of the difficult airway. To standardize the assessment, measurements are taken in supine, mid-sagittal plane, closed mouth, relaxed tongue, and tip gently touching the incisors and makes no sound. Tongue volume is found to have the greatest diagnostic power for difficult airways.8 Tongue thickness of >6.1 cm is labeled as an independent risk factor for predicting difficult intubation, with sensitivity and specificity of 0.75 and 0.72, respectively.
Hyomental distance with derived ratio: HMDR refers to the ratio of the HMD measured in the extended position to the distance measured in the neutral position. An increase of ≤ 20% in HMD during hyperextended position or a ratio of sniffing to neutral position ≤1.06 predicts difficult intubation.
Other measurements: A few more indices assess difficult airway, such as condyle translation and epiglottic distances ratio. Condyle translation displacement of ≤10 mm during the opening of the mouth indicates difficulty in laryngoscopy. The ratio of pre-epiglottic soft-tissue space to the epiglottis to the midpoint of vocal cord (PE/E-VC) may be an independent risk factor for predicting difficult laryngoscopy with a sensitivity of 67–68%. However, some studies have shown that the sensitivity and specificity of this parameter vary significantly in different studies, and it is not recommended as an indicator.95
 
Artificial Intelligence
The Difficult Airway Management Guidelines of all societies emphasize the importance of early identification and planning of difficult airways.4 Artificial intelligence (AI) predicting difficult airways is a field worthy of further researches. Recent literature shows that AI facial recognition technology is expected to replace experienced doctors in the fully automatic intelligent assessment of difficult airways and optimize the clinical work to reduce the risk of misdiagnosis of difficult airways.
 
AI Combined with Imaging-assisted Modeling in Difficult Airway Assessment
It has been found that the predictive value of the computer-aided model constructed using the random forest algorithm was significantly better than the currently latest clinical predictive scale model and the predictive model constructed by traditional logistic regression analysis. By analyzing and processing facial images through machine learning algorithms, critical points of the face are analyzed, considering the discriminative ability of each parameter through logistic regression.
 
AI Combined with Facial Images in Difficult Airway Assessment
This is a fully automated system to collect a patient's facial photo in different scenarios, such as mouth open, tongue stretched out, and head stretched vertically and laterally rotated. Then machine learning algorithms were used to analyze and process the facial photos to predict difficult airways.
 
Airway Assessment in Intensive Care Unit
Full airway assessment in a critically ill patient is often impractical; however, a basic airway assessment, such as previous records, body habitus, external predictors, and USG can be performed safely. In a multicentric study, De Jong et al. developed and validated a score (MACOCHA) to predict the difficult airway in critically ill patients (Table 1). The score included seven parameters, out of which four were patient-related, two were pathology-associated, and one was operator-related. Each parameter has been given one point except for Mallampati and OSA, with five points and two points each. The difficulty of intubation increases as the score increases from 0 to 12, but a cutoff value of ≥3 is taken as a predictor of difficult intubation in critically ill patients. This test has a sensitivity of 73% and has not been validated for VLs.106
TABLE 1   MACOCHA score for airway assessment.
Factors
Points
Patient-related
Mallampati score III or IV
5
Apnea syndrome (obstructive)
2
Cervical spine limitation
1
Opening mouth <3 cm
1
Pathology-related
Coma
1
Hypoxemia
1
Operator related
Non-Anesthesiologist
1
Note: MACOCHA: Mallampati score III or IV, Apnea syndrome (obstructive), Cervical spine limitation, Opening mouth <3 cm, Coma, Hypoxemia, Non-Anesthesiologist. Scores: from 0 (easy) to 12 (very difficult). Source: Adapted from De Jong A, Molinari N, Terzi N, Mongardon N, Arnal JM, Guitton C, et al. Early identification of patients at risk for difficult intubation in the intensive care unit: Development and validation of the MACOCHA score in a multicenter cohort study. Am J Respir Crit Care Med. 2013;187(8):832-9.
 
RECENT CONCEPTS IN AIRWAY
 
Physiologically Difficult Airway
It is defined as the airway in which reduced physiological reserve pertaining to a disease process places the patient in a potentially life-threatening situation during intubation and transition to mechanical ventilation. The distinction between anatomical and physiological difficult airways is crucial because awake intubation is the gold standard in predicted an anatomically difficult airway. In contrast, awake intubation can worsen the already deranged physiology of a critically ill patient in case of inadequate blunting of airway reflexes, such as sudden rise in intracranial pressure or cardiac ischemia in the predisposed individuals. Various types of physiologically difficult airways have been described in the literature, but the presence of hypoxemia and hypotension with a shock index of ≥0.9 increases the risk of cardiac arrest by almost fourfold (Table 2).10
 
Preoxygenation
In certain patients with a physiologically difficult airway, such as having an increased alveolar-arterial (A-a) gradient, the traditional method of preoxygenation is ineffective. Therefore, these patients should be preoxygenated using NIPPV [inspiratory pressure 5–15 cm, positive end-expiratory pressure (PEEP) 5 cm, tidal volume 6–8 mL/kg] in a head-up position or with a high-flow nasal cannula with oxygen flow at 70 L/min in patients of moderate hypoxemia. It decreases shunt fraction by recruitment of collapsed alveoli.107
TABLE 2   Types of physiologically difficult airways.
Physiological derangement
Mechanism
Management
Hypoxemia
Limited oxygen reserve leading to rapid desaturation during apnea
  • Preoxygenation:
    SpO2>95%: NRB/BVM+HFNC
    SpO2<95%: NIPPV/BVM+PEEP plus HFNC
  • Apneic oxygenation and ventilation
  • Supraglottic
  • Delayed-sequence intubation (DSI)
  • Head-elevated positioning
Hypotension
Decreased venous return with PPV, attenuation of catecholamine surge with the resolution of hypoxia/hypercarbia, vasodilation and myocardial depression
  • Resuscitate before intubation: Two peripheral IV lines, volume loading ± blood in responders
  • Norepinephrine infusion in nonresponders while epinephrine boluses (10–50 µg) can be given in urgent situations
  • Phenylephrine bolus for transient vasodilation
  • Use hemodynamically stable induction agents
Right ventricular (RV) failure
RV afterload is further increased due to PPV, PEEP, and HPV
  • Bedside Echo is quite useful to differentiate dysfunction and failure
  • Avoid factors causing HPV
  • Adequate preoxygenation and apneic oxygenation
  • Ventilation with low mean airway pressures
  • Pulmonary vasodilator, e.g., inhaled nitric oxide (iNO) and epoprostenol
  • Avoid any fluid, resuscitate with norepinephrine
Severe metabolic acidosis
Compensatory hyperventilation interruption by any brief period of apnea leads to a profound drop in pH and consequent cardiovascular collapse
  • Try to avoid intubation and put on NIPPV till correction
  • Ventilator-assisted preoxygenation
  • Maintain spontaneous respiration—awake intubation
  • Try to avoid RSI or use low-dose sedatives and short-acting NMB
  • Maintain preintubation etCO2 and RR
  • Consider pressure mode ventilation
  • No role of bicarbonate therapy
Neurological
Sudden increase of ICP during RSII in TBI and stroke can cause secondary injury to brain
  • Invasive BP monitoring
  • Blunt stress response
  • Induce with propofol, thiopentone, ketamine, and midazolam
  • Avoid succinylcholine8
Hepatic
Hepatic failure patients have raised ICP due to hepatic encephalopathy
  • Follow neuroprotective strategy
  • Consider coagulopathy and bleeding
Renal
Severe metabolic acidosis leads to exhaustive hyperventilation. Any interruption during intubation leads to acidemia and dangerous hyperkalemia
  • Avoid succinylcholine
  • vasopressor should be used
  • Soda bicarbonate infusion can be considered
Gut
Risk of regurgitation and aspiration
  • Use RSII and fluid resuscitation
Sepsis
Distributive shock, lactic acidosis and coagulopathy
  • Use fluid resuscitation, vasopressors
  • Induction with ketamine
(BP: blood pressure; BVM: bag valve mask; etCO2: end-tidal carbon dioxide; HFNC: high frequency nasal cannula; HPV: hypoxic pulmonary vasoconstriction; ICP: intracranial pressure; NIPPV: noninvasive positive pressure ventilation; NMB: neuromuscular blocker; NRB: nonrebreather mask; RR: respiratory rate; RSII: rapid-sequence induction intubation; SpO2: oxygen saturation; TBI: traumatic brain injury) Source: Adapted from Ahmed SM, Athar M. Practice changing updates in airway management in critically ill patients. In: Todi S, Dixit SB, Chaudhry D, Mehta Y (Eds). Critical Care Update 2020, 2nd edition. New Delhi: Jaypee Brothers Medical Publishers; 2020. pp. 18-25.
 
Apneic Oxygenation
It is defined as providing a continuous supply of oxygen from the beginning of apnea until the initiation of positive-pressure ventilation. The constant uptake of oxygen with just 8–20 mL/min of CO2 diffusion in alveoli creates a pressure gradient between the upper airway and alveoli, leading to the bulk flow of oxygen-rich gases. However, patency of the airway is mandatory for this phenomenon to occur. Dead-space ventilation and cardiogenic oscillations further augment apneic ventilation. With effective preoxygenation, continuous high-flow oxygen, and patent airway, PaO2 9can be maintained for >100 mm Hg for >100 minutes, but with severe hypercapnia and acidosis (PaCO2 increases 5 mm Hg in the first minute followed by 3 mm Hg per minute). Complications of prolonged apneic oxygenation include hypercarbia, acidosis, hyperkalemia, raised intracranial pressure, and pulmonary hypertension. Transnasal humidified rapid-insufflation ventilatory exchange (THRIVE) creates a continuous positive airway pressure (CPAP) of around 7 cm H2O, causing the opening of small airways and consequent CO2 clearance. The rise of CO2 is approximately one third of the expected values.10
 
Delayed-sequence Intubation
Modified rapid-sequence intubation (RSI) with cricoid pressure (can be released in case of inadequate visualization) and adequate denitrogenation are the techniques of choice in emergencies. However, altered, agitated, and noncooperative patients cannot be adequately preoxygenated, leading to desaturation during the period of apnea. To overcome this situation, Weingart11,12 came with the concept of “delayed-sequence intubation (DSI)”, where the induction agent is temporally separated from the administration of the muscle relaxant to allow adequate preintubation preparation. A small dose of ketamine is used to sedate the patient to achieve adequate preoxygenation before paralysis. This technique of DSI is shown to have drastically improved the safe apnea time in critically hypoxemic uncooperative patients. Ketamine sequence intubation (KSI), also called graded sequence intubation (GSI), is another technique proposed by Reuben Strayer. It is similar to DSI, except that neuromuscular blockade is not used.10
 
Cannot-intubate Cannot-oxygenate
Traditional Can't-intubate Can't-ventilate (CICV) has been now changed to “cannot-intubate cannot-oxygenate (CICO)” situations when all efforts to oxygenate the patient using a facemask, supraglottic airway device (SAD), and tracheal intubation have failed, and the patient is consuming oxygen faster than it can be delivered and is at risk of imminent hypoxic brain injury, cardiac arrest, and death. The quickest method of oxygenating a patient in this situation is to recognize the CICO emergency and perform an emergency FONA, usually in the form of a cricothyrotomy. CICO emergencies are rare and are associated with significant mortality and morbidity, especially if there is a delay in recognizing the situation or performing cricothyrotomy.13
 
Complete Ventilation Failure
In a situation when the airway manager is unable to face mask ventilate, intubate a patient, and insert a SAD, the Difficult Airway Society (DAS) had 10labeled the condition as CICV in 2008, which was subsequently coined as CICO in 2015. However, the All India Difficult Airway Association guidelines define complete ventilation failure (CVF) as a trigger for surgical airway. This is a situation where intubation, ventilation using SAD, and face mask have failed after giving the best attempt, even if oxygenation may be maintained. They recommend proceeding to emergency cricothyroidotomy when there is CVF even if oxygenation could be maintained, not only when hypoxemia sets in. During these events, nasal oxygen insufflation should continue. Before declaring CVF, a final attempt at mask ventilation should be made after ensuring complete muscle relaxation. This will give the best chance for optimizing mask ventilation and also create good operating conditions for cricothyroidotomy.14
 
NEWER DEVICES IN AIRWAY MANAGEMENT
 
Videolaryngoscope
Since the development of GlideScope in 2001, several VLs have flooded the market. Despite few limitations associated with VLs, these devices have been shown to improve the laryngeal view and success rate of tracheal intubation. They have now become the first backup technique after failed intubation attempts. Most of the difficult airway guidelines emphasize the role of VL in the management of both anticipated and unanticipated difficult airways and even as the first choice in COVID patients.1517
Of the various VLs available, each is unique in design. They can be categorized into three main types—one with the standard Macintosh-shaped blade, one with the angulated blade, and one with a channel for tube passage. The channeled VL has a tube slot to deliver the endotracheal tube (ETT). In channeled VL, the tube cannot be manipulated independently and hence, the whole of the scope blade must be directed toward the glottis. The larynx may not be directly visible in VL having blades angled at 60° upward (e.g., GlideScope, McGrath). A stylet is required while intubating with these blades. On the contrary, Storz DCI and C-MAC blades are similar to the conventional Macintosh, which does not require stylet during intubation (Flowchart 1).
 
Endotracheal Tubes
 
VivaSight
VivaSight are new-generation single- and double-lumen tubes with an integrated high-resolution camera. The integrated camera technology makes the placement of the tube fast and effective and provides continuous visual monitoring of ETT and endobronchial blocker placement throughout the procedure. VivaSight-SL is indicated for use during routine and difficult intubation procedures. Together with the single-use endobronchial blocker and VivaSight-EB, lung isolation can be fast and effective, ensuring that dislocations are easily detected and corrected.1811
zoom view
Flowchart 1: Classification of different videolaryngoscopes
 
TaperGuard™
Endotracheal tube designs to decrease the risk of ventilator-associated pneumonia (VAP) include supraglottic suctioning or modifications of the cuff shape. The TaperGuard™ (Covidien, Boulder, CO) ETT has a tapered, polyvinyl chloride cuff designed to reduce microaspiration around channels that form with a standard barrel-shaped cuff. Multiple independent and manufacturer-sponsored laboratory and clinical trials have demonstrated the decreased passage of fluid or dye around the ETT compared with conventional barrel-shaped cuffs. But recently, clinical evaluations in relatively small studies of unselected patient populations have failed to demonstrate a decrease in the incidence of postoperative pneumonia.19
 
Suction above Cuff Endotracheal Tube
Peritubal leak and aspiration of the oropharyngeal secretions are primarily responsible for the occurrence of VAP.20 Tracheal tubes with a suction port above the cuff can assist in reducing the rate of VAP. As the Suction Above Cuff Endotracheal Tube (SACETT) facilitates the suctioning of excessive secretions in the subglottic area, it is preferred in ICUs as a modality to decrease VAP.12
 
AI-assisted ETT Placement
Misplaced ETT is a common finding in nonoperating room-intubated patients. To overcome this issue, GE Healthcare has developed AI-installed X-ray machines that can detect and alert the physician about any ETT malposition along with other radiological abnormalities, such as pneumothorax and collapse, immediately.21
 
Automated Cuff Pressure Regulator
Tracoe Smart Cuff ManagerTM monitors and automatically regulates the internal pressure of high-volume low-pressure cuffs of tracheostomy tubes and ETTs. It is associated with a reduced incidence of cuff pressure underinflation or overinflation than routine manual intermittent correction.22
 
Supraglottic Airway Devices
Supraglottic airway devices with a conduit for blind tracheal intubation are gaining popularity as a bridge connecting ventilation and intubation in all genres of patients. Laryngeal mask airways (LMAs) with intubation conduit are useful and are also recommended by “All India Difficult Airway Association” guidelines 2016.14
 
LMA Gastro
This second-generation, silicone-based, cuffed LMA offers an additional and separate channel for the passage of instruments (such as an endoscope) of up to a width of 16 mm in diameter. While the majority of gastrointestinal endoscopies are performed under conscious sedation by nonanesthesia personnel, there is a shift toward deep sedation or general anesthesia for advanced procedures and interventions, especially for patients with higher American Society of Anesthesiology (ASA) physical status of ≥3, high BMI, OSA, and severe comorbidities that require the presence of an anesthesiologist. New LMA Gastro™ Airway demonstrates good efficacy in adults as well as pediatrics without any detrimental or harmful side effects.2325
 
LMA Protector
The LMA Protector™ (Teleflex Medical, Co. Westmeath, Ireland) is a single-use, second-generation SAD designed with a large volume conduit with gastric access and a fixed curved structure to facilitate insertion. The medical-grade silicone inflatable cuff has been built for a primary oropharyngeal seal and distal esophageal seal, potentially improving the ability of the LMA Protector™ in providing positive-pressure ventilation and preventing aspiration. It has a dual gastric channel, silicone cuff pilot technology, and second seal with an intubation facility.2613
 
Endoscope
 
Flexible Intubation Video-endoscope
Flexible Intubation Video Endoscope (FIVE) from KARL STORZ offers a single-use solution that is remarkable in every respect. It is suitable for airway inspection, suction of bronchial mucus, and foreign body removal and biopsies. It is compatible with the multifunctional C-MAC® monitor.
 
Surgical
 
Front-of-neck Airway Access
Various new devices have been introduced in the market for easy surgical access. A brief description of the recent advances in the surgical airway is shown in Table 3.27
TABLE 3   Newer devices in surgical airway.
Device
Manufacturer
Description
Needle cricothyrotomy
Emergency transtracheal airway catheter
Cook medical
It has a reinforced fluorinated ethylene propylene catheter.
Percutaneous cricothyrotomy
Quicktrach I, II
VBM
Quicktrach I (without cuff) and Quicktrach II (with cuff). Set includes airway catheter, stopper, needle, and syringes that come preassembled.
Pertrach emergency cricothyrotomy kit
Pulmodyne
It includes two splitting needles, cuffed or uncuffed trach tube, dilator with flexible leader, twill tape, syringe, extension tube and scalpel
Melker cricothyrotomy kit
Cook medical
Complete set including syringe (10 cc), 2- to 18-G introducer needles with TFE catheter (short and long), 0.038-in diameter Amplatz extra-stiff guidewire with flexible tip, scalpel, curved dilator with radiopaque stripe and PVC airway catheter.
Surgical cricothyrotomy
Surgicric
VBM
Surgicric I: rapid 4-step technique Surgicric II: classic surgical technique Surgicric III: Seldinger technique
Scalpelcric
VBM
Scalpel cricothyrotomy set “stab- twist-bougie-tube”14
Rusch Easycric
Teleflex
Seldinger-based cricothyrotomy percutaneous set, premounted EasyCric soft 5-mm ID PVC tube and rigid ergonomic dilator (hydrophilic coating, anatomically shaped). The set contains syringe and needle, saline, nonkinking guidewire with both flexible ends and scalpel
Melker surgical cricothyrotomy set
Cook medical
Cuffed cricothyrotomy tube, scalpel, tracheal hook Trousseau dilator, and blunt, curved dilator in compact package for convenient storage
Percutaneous dilatational tracheostomy
Ciaglia blue rhino G2 PCT set
Cook medical
Kit includes 24, 26, and 28 Fr loading dilators and Shiley 6 or 8 percutaneous disposable dual-cannula tracheostomy tube
Portex Ultraperc
Smiths medical
Complete set with or without a tracheostomy tube.
Shiley Tracheosoft XLT (extended length)
Medtronics
Available in 4 sizes (5, 6, 7, and 8 mm ID). Each size offers the choice of cuffed or uncuffed stylets, and proximal or distal extensions with disposable cannula.
Venner PneuX
Venner medical
Works with a cuff pressure controller that regulates pressure within the cuff as a complete system for the prevention of VAP in intensive or critical care patients.
(PVC: polyvinylchloride; TFE: tetrafluoroethylene; VAP: ventilator-associated pneumonia) Source: Adapted from Hagberg CA. Current concepts in the management of the difficult airway. 2021;17.
 
DEVICES FOR SPECIAL AIRWAY SITUATIONS
 
Intubation Box
The coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus continues to spread, infecting millions worldwide. To minimize peri-intubation healthcare worker infection risk from COVID-19, an additional protection barrier known as an aerosol box or intubation box was introduced. Although hospitals worldwide have used various prototypes of aerosol boxes, their effect on intubation remains unclear. It has been observed that the time to intubation was significantly longer when an aerosol box was used than VL alone.283015
 
MADgic® (Teleflex)
The MADgic® Laryngo-Tracheal Mucosal Atomization Device is used to administer medications across the entire upper airway and beyond to prepare the airway for awake intubation. The MADgic® device is not prefilled so the clinician can select the type of medication and exact dosing desired. The malleable stylet enables precise, targeted delivery specific to the patient's anatomy. Various modifications of this device are popular in markets, such as MADgic Airway, combining atomized topical anesthetic and oxygen delivery in a flexible-scope compatible airway. MAD nasal is another device for delivering medications to the nose and throat. The typical particle size delivered is 30–100 µ.
 
Optiflow THRIVE (Fisher & Paykel)
It is a humidified oxygenation system with heated inspiratory tubing and anatomically designed high-flow nasal cannula. They are used chiefly to provide high-flow oxygen therapy.
 
SuperNO2VA Nasal PAP Ventilation (Vyaire Medical)
This nasal mask delivers NIPPV when connected with the ventilatory circuit or resuscitation bag. It is ideal for patients with OSA, morbid obesity, cardiopulmonary disease, and patients requiring endoscopy under mild sedation.
 
O2-MAXTM Trio (Pulmodyne)
It is a disposable CPAP device with an integrated nebulization facility. It is provided with three FiO2 (30, 60, 90) and PEEP (2.5–20 cm H2O) settings.
 
Ventrain Device (Ventinova Medical)
It is a manually operated ventilation device through a transtracheal catheter during CICO situations. Ventilation is based on bidirectional flow. It supplies not only oxygen during inspiration but also suction air during the expiratory phase. It requires a high-pressure oxygen source with a pressure compensated regulator.
 
Chin-UP® Airway Support Device (Dupaco)
It is a hands-free airway support device used to lift and hold the patient's chin during monitored anesthesia care (MAC) and total intravenous anesthesia.16
 
Troop Elevation Pillow (CR Enterprises-Mercury Medical)
It is a foam-based positioning device that quickly achieves laryngoscopic position. It is beneficial for patients with difficult airway and obesity. It also offers an added advantage of infection control with its barrier covers.
 
Robotic Intubation
It is a short step technologically to replacing the human with sensors to map the airway and guide the intubation stylet into the trachea. Engineers have built such intubating robots that use electromagnetic guidance (Ohio State) and infrared light (Hebrew University).31 In emergencies, the necessity to perform tracheal intubation may occur unexpectedly, infrequently, and under unfavorable conditions. Robotic Endoscope Automated via Laryngeal Imaging for Tracheal Intubation (REALITI) has been developed to enable automated tracheal intubation.32 By using the capacity of REALITI for real-time image recognition and automated distal tip orientation, comparable results have been obtained in anesthetists and lay participants with no medical training in manikin-based study.32 Apart from this remote robot-assisted intubation system (RRAIS), Intu-bot and Kepler intubation systems have also been used.3335 Despite this, further research and time are required to authenticate and incorporate these in clinical practice.
 
CONCLUSION
Although many technologies are being introduced every day, we must excel in basic techniques and skills of airway management. Availability of advanced devices and recent innovations ranging from AI to robotic intubation assist anesthesiologists, currently it is difficult to predict if they can replace humans in the near future. However, the pace with which these are being developed, it is very likely that they may surpass human competence in due course of time.
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