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Management of the Difficult Airway. A. Joseph Layon, MD, FACP Professor of Anesthesiology, Surgery & Medicine Chief, Division of Critical Care Medicine University of Florida College of Medicine, Medical Director, Gainesville Fire Rescue Service Gainesville, Florida, USA. Outline.
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Management of the Difficult Airway A. Joseph Layon, MD, FACP Professor of Anesthesiology, Surgery & Medicine Chief, Division of Critical Care Medicine University of Florida College of Medicine, Medical Director, Gainesville Fire Rescue Service Gainesville, Florida, USA
Outline • Characteristics of the DA • Etiology of respiratory failure in trauma • Trauma airway as Difficult Airway • F-A-S-T Evaluation and Prediction of the airway • Airway Pharmacology: Management out of OR • Management strategy • Old gadgets and new gadgets • Confirming endotracheal intubation
ICUs Floor Special Diagnostic Stations Inter-facility Transport Hypoxia Hypercarbia Intolerable WOB Current / imminent inability to protect airway Neurological Impairment Hemodynamic Instability Cardiac Arrest Special Diagnostics Trauma - DA: Not only in the ED…
Patients Sicker Unknown Fewer Resources People Equipment Time ED – Floor – ICU… NOT the OR
Trauma Airway = Difficult Airway Difficult Intubation: > 3 attempts to intubate in 10 minutes ASA • Difficult Intubation > 1 attempt with the same blade or • a change in blade or adjunct to DL; • Use of alternative devices / techniques when intubation has failed. CSA
Frequently Complicated P-value, risk ratio (95% CI) Hospital Location % Patients Complications Surgical ICU (32 beds) Medical ICU (16 beds) Floor Neurosurgical / trauma (10 beds) ED Coronary ICU (12 beds) Radiology / cardiac catheterizations / PACU 27 21 16 12 10 9 5 Bradycardia Regurgitation Aspiration Hypoxemia Hypoxemia < 0.04, 1.5 (1.1-2.2) < 0.004, 1.9 (1.2-2.9) < 0.002, 3 (1.6-5.7) < 0.03, 0.6 (.43-93) < 0.001, 1.7 (1.7-2.2) Hartford Hospital119 month study, 2,833 patients intubated with questionnaires . 24/7 anesthesiology emergency airway service ICU = intensive care unit, PACU = postanesthesia care unit, % patients are for the entire database. Complication rate / RR / CI compared to other areas studied. Mort T A&A 2004;99:607-13
May be more difficult than usual % Patients 2 or fewer attempts (%) > 2 attempts (%) Primary Disease Category All groups combined Cardiac (CHF, MI, arrhythmia) Pulmonary (pneumonia, aspiration, COPD, secretions) Sepsis-SIRS (pulmonary, abdominal, misc.) Neurosurgical/neurological (CVA, seizure, trauma) Trauma Metabolic (DKA, Renal or liver failure, OD) GI bleeding 90 93.2 89.8 93.7 86.9 87.8 90.2 85.9 10 6.8 10.2 6.7 13.1* 13.9* 9.8 14.1* 28 24 16 14 12 4 2 MI = myocardial infarction; CHF = congestive heart failure; COPD = chronic obstructive pulmonary disease; Misc = miscellaneous; CVA = cerebral vascular event; DKA = diabetic ketoacidosis; GI = gastrointestinal; SIRS = systemic inflammatory response syndrome; OD = overdose *P < 0.03 when compared with sepsis and cardiac groups Mort T A&A 2004;99:607-13
More Difficult = Complications < 2 Attempts (90% Pts.) > 2 Attempts (10%)* RR for > 2 attempts (95% CI) Complication 9 (4.2-15.9) 14 (7.4-24.3) 6 (3.7-8.7) 7 (2.8-10.1) 4 (1.9-7.2) 4 (1.7-6.7) 7 (2.4-9.9) 70% 28% 51.4% 22% 13% 18.5% 11% 10.5% 1.9% 4.8% 1.9% 0.8% 1.6% 0.7% Hypoxemia (SpO2 < 90%) Severe Hypoxemia (SpO2 < 70%) Esophageal Intubation Regurgitation Aspiration Bradycardia Cardiac Arrest * All categories p < 0.001 comparing < 2 with > 2 attempt groups Mort T A&A 2004;99:607-13
Sometimes Lethal… Schwartz DE et al. Anesthesiology 1995;82:367 • Death as a Complication of Emergency Airway Management in Critically Ill Adults: Prospective Investigation of 297 Tracheal Intubations • 10 month study • 238 adult ICU patients / 297 consecutive translaryngeal tracheal intubations • Mortality: • 7 deaths (3%) in 270 non-CA intubations • During or within 30 minutes of intubation • Difficult Intubation: > 2 attempts at intubation. • 8% intubations
Implications….. • The Difficult Airway (> 1 to 3 “attempts”) • ED, Floor, ICU • DA High risk for complications • INCLUDING DEATH • Thus this high risk situation must be recognized BEFORE attempting to access the airway
ASA Difficult Airway Algorithm • During 1990’s • Adverse Outcome due to Airway Management • Decreased significantly • ? Due to institution of ASA DA algorithm ? Anesthesiology 1991;75:1087 Anesthesiology 1993;78:597
ASA Difficult Airway Algorithm • Second Iteration • ASA House of Delegates • Approved October 2002 • Practice Guidelines for Management of the Difficult Airway • An Updated Report by the ASA Task Force on Management of the Difficult Airway • Evidence Based Guidelines • Anesthesiology 2003;98:1269 • www.asahq.org
Improved recognition of the Difficult Airway LIMITED EXAM: Uncooperative patient Patient In Extremis ASSUME DIFFICULT AIRWAY Oxygen Delivery Required Pre-Oxygenation prior to induction of GA Supplemental O2 during DA management LIMITED: COOPERATION AVAILABILITY Prioritize “Cannot Ventilate Options” Based on familiarity & availability of LMA AVAILABILITY OF EQUIPMENT IMPERATIVE Confirmation of ETT Placement Required AVAILABILITY OF EQUIPMENT: IMPERATIVE ASA DA Algorithm:FOUR Significant Practice Changes • Anesthesiology 2003;98:1269 • www.asahq.org
Outline • Characteristics of a trauma patients • Etiology of respiratory failure in trauma • Trauma airway as a the Difficult Airway • F-A-S-T Evaluation and Prediction • Airway Pharmacology: Outback management • Management strategy • Old gadgets and new gadgets • Confirming endotracheal intubation
Basis for Airway Classification • Physical / Measured Features • TM distance, Mouth Opening… • Mallampati Score • Samsoon and Young modification • Laryngoscopy classification
60% VERY EASY 7% VERY DIFFICULT 6% VERY DIFFICULT
X-treme Mallampati: 0 Ezri, et al. Anesth Analg 2001;93:1073
Overall intubation success, patient conditions permitting physiognomic airway assessments, and rapid sequence intubation failures Not Following Simple Commands and C-Spine Immobilized Following Simple Commands and No C-Spine Precautions Non- Cardiac Arrest Not Following Simple Commands* Total Intubations C-Spine Immobilized Failed RSI (all RSI = 838)* Total (%, 95% CI) -- 944 3 850† 3 452 (53, 50-57) 1 370 (43, 40-47) 1 210 (25, 22-28) 0 271 (32, 29-35) C-spine, Cervical spine; RSI, rapid sequence intubation *A GCS motor score of <6 or specific medical record documentation (“not following commands”) was used to define this †Twelve non-cardiac arrest patients were intubated without RSI (nasal, 8; laryngoscopy but with induction agents only, 4); 838 patients underwent RSI, of whom 597 were trauma patients and 241 were medical patients Levitan RM Ann Em Med 2004; 44: 307-313
Implications • Mallampati Classification • Gives a rough idea of ease of intubation • Can be erroneous • 6% to 7% of Class 2 to 3 (2 to 4 S-Y modification) • Very difficult • Altered mental status obviates evaluation • Expect difficulty
Outline • Characteristics of a trauma patients • Etiology of respiratory failure in trauma • Trauma airway as a the Difficult Airway • F-A-S-T Evaluation and Prediction • Airway Pharmacology: Outback management • Management strategy • Old gadgets and new gadgets • Confirming endotracheal intubation
Induction Agents and Trauma Hypovolemia Myocardial Depression? DRUG DOSE ONSET OFFSET T1/2 T1/2 Induction Propofol 1-2 mg/kg 22-125 sec 5-10 min 2-2.3 m 29-44 m Infusion 10-100 mcg/kg/min Etomidate 0.25-.5 mg/kg < 60 sec 5 min 2.7 m 3 + 1 hr Ketamine 1-3 mg/kg < 60 sec 10-15 min 17 min 3 hr Infusion 0.5-3 mg/kg/hr 79 m Midazolam 0.1-.3 mg/kg 30-60 sec 6-15 m 6-15 m 1.7-4 hr Infusion 0.5-1 mcg/kg/min Thiopental 1-4 mg/kg 30-60 sec 10-15 m 5-8 m 5-17 hr Increased ICP
1 mg / Kg lean body weight Sux ED95 is 0.25 mg / Kg (that is plenty for trauma) NMB Agents for RSI and Trauma DRUG DOSE ONSET OFFSET Succinylcholine 1-1.5 mg/kg 30-60 sec 5-10 min Benzylisoquinolinium NMBs Mivacurium 0.3 mg/kg 90 sec 19-60 min Cisatracurium 0.4 mg/kg 60-90 sec 75-100 min Atracurium 0.6 mg/kg 60-90 sec 75-100 min Aminosteroid NMBs Rocuronium 0.3 mg/kg 60-90 sec 25-30 min Vecuronium 0.3 mg/kg 60-90 sec > 120 min …or None
NMB and Remote Locations: Real World Anesthesiologist Perspective “Induction” Medications % patients Topical local anesthetic or nothing Thiopental (0.5-5 mg / kg, 75-500 mg) Midazolam (0.02-0.12 mg / kg, 1-9 mg) Midazolam & morphine (0.02-0.07 mg / kg of each, 2-5 mg each) Morphine (0.04-0.1 mg / kg, 2-8 mg) or fentanyl (50-150 µg) Etomidate (0.04-0.25 mg / kg, 4-25 mg) Propofol (0.5-1.9 mg / kg, 40-240 mg) Diazepam (0.05-0.12 mg / kg, 5-10 mg), methohexital (0.3-1.2 mg / kg, 30-130 mg) Muscle relaxant depolarizer-succinylcholine (81% of total use) nondepolarizer-vecuronium, rocuronium (19% of total use) 17 10 27 6 7 27 4 2 20 Mort T A&A 2004;99:607-13
NMB Agents in Emergency Setting... Especially long acting ones….. may well cause problems
Time to Functional Recovery After Succinylcholine vs. Hemoglobin Desaturation: A False Perception of Safety Your patient APNEA
Succinylcholine outside the OR… Total N = 383 Field Trauma Patients ER Docs N = 373 N = 2 N = 8 OR Docs Gerich TG et al J Trauma 1998;45:312-4 Li et al, Am J Emerg Med 1999;17:141‑3
Who is the Beauty, Who the Beast ? Emergency Medicine Anesthesia Age, yrs (range) Gender, male, % Race, % Black White Other Type of trauma, % Blunt Penetrating Inhalation Injury Severity Score (range) 38.6 (37.0-40.3) 80.8 69 28.4 2.6 51.5 46.3 2.2 19.7 (18.0-21.4) 37.8 (35.6-39.9) 83.8 70.4 26.5 2.1 62.6 33.9 3.5 17.7 (15.5-19.9) Levitan RM, Ann Emerg Med, 2004;43:48-53
The Beauty or the Beast? Emergency Medicine Anesthesia Total intubations Nasal intubation (no DL tried) Total DL Attempted Total DL attempts unknown Total DL attempts known Successful intubation by DL Intubated on first DL, no. (%) Intubated on second DL, No. (%) Intubated >3, No. (%) [95% CI]* Cricothyrotomy (ie, failed DL†), No. (%) 460 1 459 3 456 454 394 (86.4%) 50 (11.0) 12 (2.6) [1.4-4.6] 2 (0.4) 198 1 197 3 194 194 174 (89.7%) 13 (6.7) 7 (3.6) [1.5-7.3] 0† * NS between ED Physicians and Anesthesiologists Levitan RM, Ann Emerg Med, 2004;43:48-53
No real difference between our ED colleagues and us…Should we leave’em alone?
Alternative Intubation and Ventilation Devices in 95 US Academic ER Programs 95/118 (81%) Programs Responded Commonest FOB (61%) Commonest TTJV (67%), CT / LMA (26% each) Levitan RM Ann Emerg Med 1999 Jun;33:694-8
No real difference between our ED colleagues and us…Should we leave’em alone? NO !! There is a difference to be eliminated
Implications • In a DA Situation….. • Want the airway experts • Want a backup plan • This can’t be • “…The Succinylcholine will wear off”
Outline • Characteristics of a trauma patients • Etiology of respiratory failure in trauma • Trauma airway as a the Difficult Airway • F-A-S-T Evaluation and Prediction • Airway Pharmacology: Outback management • Management strategy • Old gadgets and new gadgets • Confirming endotracheal intubation
The Art of Ventilation …Your first back-up method
The Critically-Ill Desaturate Quickly… APNEA Your patient
Lung Compliance: Decreased in the Difficult Intubation Wenzel V. Current Opinion in Critical Care 1997; 3:206-213
Lower Esophageal Sphincter (L.E.S.) Pressure Decreases After Cardiac Arrest min cm H2O Bowman et al. Ann Emerg Med 1997;26:2:216-219
LES Pressure During CA: Humans Gabrielli, et al Anesthesiology 2005
Sellick Maneuver • Patient supine • Head in neutral or extended (sniffing) position; • Cricoid cartilage pushed dorsally • With thumb and forefinger to occlude esophagus; • Compressing against C6 anterior; • Prevents passive regurgitation • Allows for BVM ventilation • “Without worry” of stomach distention. Sellick BA, Lancet, 1961;2:404
= 1 Kg Vanner R Anaesthesia 1999 54: 1-3
The Difficult Airway Algorithm: A Simple Strategic Approach 1 3 2
Overall intubation success, patient conditions permitting physiognomic airway assessments, and rapid sequence intubation failures Not Following Simple Commands and C-Spine Immobilized Following Simple Commands and No C-Spine Precautions Non- Cardiac Arrest Not Following Simple Commands* Total Intubations C-Spine Immobilized Failed RSI (all RSI = 838)* Total (%, 95% CI) -- 944 3 850† 3 452 (53, 50-57) 1 370 (43, 40-47) 1 210 (25, 22-28) 0 271 (32, 29-35) C-spine, Cervical spine; RSI, rapid sequence intubation. *A GCS motor score of <6 or specific medical record documentation (“not following commands”) was used to define this †Twelve non-cardiac arrest patients were intubated without RSI (nasal, 8; laryngoscopy but with induction agents only, 4); 838 patients underwent RSI, of whom 597 were trauma patients and 241 were medical patients. Levitan RM Ann Em Med 2004; 44: 307-313
Outline • Characteristics of a trauma patients • Etiology of respiratory failure in trauma • Trauma airway as a the Difficult Airway • F-A-S-T Evaluation and Prediction • Airway Pharmacology: Outback management • Management strategy • Old gadgets and new gadgets • Confirming endotracheal intubation
Nasal better tolerated If not contraindicated head trauma coagulopathy Expect secretions / blood Glycopyrrolate 0.2 mg IV If you have time Prepare the nasopharynx Phenylephrine spray Nasal trumpets / lubricants Be ready with Esmolol / NTG boluses Fiberoptic Intubation F-A-S-T • Premedicate • Aerosol 4% lidocaine • 10 mL (+ racemic epi / glycopyrrolate)