Airway Management & Safety Concerns Experience from Bariatric Surgery

Transcription

1 Airway Management & Safety Concerns Experience from Bariatric Surgery Issues of the Obese Critical Care Patient - Airway Srikantha Rao MBBS MS Associate Professor Department of Anesthesia Aug 2010

2 Objectives At the conclusion of this educational activity, participants should be able to: Identify a potential difficult airway Discuss common airway management techniques in the obese & critically ill

3 AIRWAY MANAGEMENT: TRACHEAL INTUBATION

4 Direct Laryngoscopy-Tracheal Intubation Rigid laryngoscopy - primary method of tracheal intubation. Despite high rates of success: uniquely difficult. Difficult aspect - visually analogous to looking down a narrow pipe at a target the size of a quarter. The opening of the mouth, the tongue, epiglottis, and laryngoscope blade all interact to restrict visualization of the larynx. Tracheal intubation must occur quickly

5 Preplanned Strategy Is important for first-pass laryngoscopy success Simple techniques external laryngeal manipulation, increasing i head elevation, use of adjuncts (stylet, bougie) in first-pass efforts. Done without changing the laryngoscope blade, extending the time of laryngoscopy requiring intervening episodes of mask ventilation (itself a risk for regurgitation) Levitan RM Airway management and direct laryngoscopy. Crit Care Clin North Am 2000;16:373 88

6 Proper positioning is a key step Supine Sniffing position moderate head elevation and atlanto-occipital occipital extension Bannister FB, Macbeth RG. Direct laryngoscopy and tracheal intubation. Lancet 1944;244, 6325:651 4

7 Tracheal Intubation

8 Supine

9 Are obese patients difficult to intubate? No No further discussion Yes Why? How can we make it easier? Brodsky JB et al. Morbid obesity and tracheal intubation. Anesth Analg 2002; 94:732 6 Juvin P et al. Difficult tracheal intubation is more common in obese than in lean patients. Anesth Analg 2003;97:

10 AIRWAY ASSESSMENT

11 Mallampati Class

12 Predicting difficult intubation Parameter Head & Neck ROM, Head Extension <80 degrees Neck length and thickness Qualitative Assessment Sternomental distance < 13cm Thyromental distance < 6cm Mouth Opening <4 cm Mallampati Class 3 or 4 Unable to protrude mandible anterior to maxilla Length of Upper Incisors Qualitative Assessment Comments Optimal Sniffing position is 35 deg neck flexion on chest and > 80 deg head extension on neck Short, thick neck more difficult Larynx is more anterior Small mandible space=larynx is more anterior Unable to place blade adequately and align axes Larger tongue/pharynx size more difficult Normal TM joint function, jaw moves anteriorly with laryngoscopy Protruding incisors more difficult

13 AIRWAY MANAGEMENT: ANATOMICAL DIFFERENCES BETWEEN THE NORMAL AND OBESE

14 Parameter Head & Neck ROM, Head Extension <80 degrees Neck length and thickness Qualitative Assessment Sternomental t distance < 13cm Thyromental distance < 6cm Mouth Opening <4 cm Mallampati Class 3 or 4 Unable to protrude mandible anterior to maxilla Length of Upper Incisors Qualitative Assessment Comments Optimal Sniffing position is 35 deg neck flexion on chest and > 80 deg head extension on neck Short, thick neck more difficult Larynx is more anterior Small mandible space=larynx is more anterior Unable to place blade adequately and align axes Larger tongue/pharynx size more difficult Normal TM joint function, jaw moves anteriorly with laryngoscopy Protruding incisors more difficult

15 Proper positioning failure Novice laryngoscopists A common mistake of novices Compensate by lifting the patient s head off of the bed with the laryngoscope. In obese patients, such lifting of the head and shoulders may be impossible.

16 Proper Positioning of the Patient The ability to obtain a good glottic view during direct laryngoscopy is the main determinant of easy tracheal intubation. ti Several methods to improve glottic view. Placing the patient s t head and neck in an optimal position is the first and perhaps the most important maneuver to routinely and predictably improve laryngoscopy and intubation outcome.

17 HELP Head Elevated Laryngoscopic Position 60 obese patients undergoing bariatric surgery, the ramped position improved ; laryngeal view when compared to a standard sniff position. 40 non-obese patients, improved laryngeal view by performing laryngoscopy in the 25-degree head-up position. Lee BJ, Kang JM, Kim DO.. Br J Anaesth 2007;99:581 6 Collins JS, et al.. Obes Surg 2004;14:1 5

18 MARGIN OF SAFETY: PHYSIOLOGIC DIFFERENCES BETWEEN THE NORMAL AND OBESE

19 Head Up Position Mask ventilating the patient's lungs before tracheal intubation. in lung and chest wall compliance, obese patients tend to desaturate quickly Supplemental oxygen in the 25-degree head-up position -a greater safety margin for induction of anesthesia by achieving 23% higher oxygen tensions. Dixon BJ, et ak. Preoxygenation is more effective in the 25 degrees head-up position than in the supine position in severely obese patients: a randomized controlled study. Anesthesiology 2005;102:1110 5

20 Significance Compared to the supine position, the Head Elevated Laryngosocpic Position is reportedly better for intubating the trachea of obese patients. This position could be achieved either by elevating the head of the patient using a stack of blankets or a specially designed pillow or by positioning the patient on the operating table with the back up. This not only improves the ease of intubation but also improves oxygenation.

21 INCIDENCE OF DIFFICULT AIRWAY IN THE PERIOPERATIVE PERIOD & ITS MANAGEMENT

22 Risk Analysis Matrix Simplified risk analysis matrix shows the relationship between severity of outcome of an event and likelihood of its reoccurrence. In general, events in the intermediate to high risk and moderate to severe severity are those which require active efforts to prevent or mitigate. Reason J. Human Error

23 Management of the Difficult Airway in Closed Malpractice Claims Gene N. Peterson, M.D., Ph.D., et al Anesthesiology, University of Washington, Seattle, Washington. Analyzed claims in the ASA Closed Claims Project database Assessed airway management factors associated with adverse outcomes from difficult intubation adoption of the ASA Difficult Airway Algorithm, 159 difficult airway claims among the 2190 claims reviewed. Compared difficult airway claims resulting in death or brain damage with difficult airway claims resulting in less severe outcomes. Statistical analysis was performed using the Z test (proportions) and the Kolmogorov-Smirnov Test (payments).

24 Management of the Difficult Airway in Closed Malpractice Claims Gene N. Peterson, M.D., Ph.D etal. Anesthesiology, University of Washington, Seattle, Washington. Conclusion: Death and brain damage were more common in difficult airway claims arising from non- OR/PACU locations. Severe outcomes were more common in the setting of difficult mask ventilation, can t intubate/can t ventilate, and persistent intubation attempts. Anesthesiology 2003; 99: A1252

25 Localtion of difficult airway non anesthetizing locations perioperative ASA Closed Claims Database Most Common Damaging Events ASA Newsletter 2004 June

26 Basic structure of DAS Guidelines Henderson, J. J., Popat, M. T., Latto, I. P. & Pearce, A. C. Difficult Airway Society guidelines for management of the unanticipated difficult intubation. Anaesthesia 59 (7),

27 Preparedness is paramount Importance of being prepared for unexpected events. Clinicians i i need to anticipate i t the risks of each situation ti and strive to structure the care environment preemptively to reduce their occurrence and impact. Optimal response in crisis situations requires availability of the necessary equipment and drugs, mental and physical readiness. Excellent clinicians prepare themselves for all possible scenarios and their risks by mentally simulating what both patients and team members might do (or not do) in different clinical situations.

28 Improve Ability to Ventilate Better patient positioning Jaw thrust Guedel airway Nasopharyngeal (although run risk of producing bleeding in already difficult situation) Apply mask with two hands and give reservoir bag to assistant t Intubating laryngeal mask (ILM) Surgical Airway

29 Tracheal Intubation in the Head-Elevated Position in Obese Patients: Laryngoscopy and tracheal intubation in the head-elevated position in obese patients: a randomized, controlled, equivalence trial. Rao SL, Kunselman AR, Schuler HG, DesHarnais S. Anesth Analg Dec;107(6):

30 Summary: Before Direct Laryngoscopy Proper positioning of patients is a key step that facilitates tracheal intubation. In obese patients, the 25 degree back-up or HELP, is better than the supine position Place blankets or other devices under the patient's head and shoulders. This position can also be achieved by reconfiguring the bed and raising the back. This table-ramp method can be used without t the added expense of positioning devices, and it reduces the possibility of injury to the patient or providers.

31 Resources