Sounds: A number of conditions associated with abnormal upper and lower airway sounds may cause difficulty with BMV. A history of snoring has been correlated with DMV. 21 As with the obese patient, this may be associated with redundant oropharyngeal tissues. Early placement of an OPA, and main- taining a head-extended position will help. Stridor is almost always a sign of patho- logic airway obstruction and should be consid- ered an ominous sign. Any patient presenting with inspiratory or expiratory stridor should be considered as potentially very difficult or impos- sible to bag-mask ventilate. The patient with “stiff”, poorly compliant lungs, (often associated with wheezing or rales) will present increased resistance to bag-mask ventilation and requires higher than normal insufflation pressure. The presence of two or more of the factors presented above significantly increases the potential for DMV. 21 The true incidence of DMV in the emergency department (ED) is not clear but is likely greater than that seen with the elective surgical population. In the operating room, DMV has been reported to occur in up to 5–8% of elective surgical patients. 19, 21 Inter- estingly, the DMV rate is twice as high (15.5%) in patients who were also described as difficult intubations. 19 Prediction of difficulty with BMV is an important component of the airway assessment, as BMV remains the “go to” method of gas exchange both before and between intubation attempts. It also represents a vital decision node in airway management in two ways: A. Decision making: Anticipated difficulty with BMV may point to the need for an awake technique for intubation, especially if difficulty with laryngoscopy is also pre- dicted (see Chap. 11). B. Defining the failed airway: In the setting of failed intubation, the inability to maintain the SaO 2 >90% with BMV defines failed oxygenation, mandating proceeding with rescue oxygenation via an extraglottic device or cricothyrotomy (see Chap. 12). One last implication of predicted difficulty with BMV is the automatic need for an addi- tional assistant, assuming a high probability of requiring a two-person technique. ᭤ BMV TIPS AND PEARLS Ideal Head and Neck Positioning for BMV Ideally, for BMV, the head and upper neck should be extended 23 (a) to attain a more direct path for the delivered volumes from face to tra- chea, (b) to maintain longitudinal tension on the lumen of the upper airway 24 and possibly, (c) to increase retrolingual and retropalatal space. 25 When studied, no additional benefit was noted with elevation of the occiput (i.e., the “sniff” position) compared with simple head tilt starting in the neutral position. 23 Gastric Insufflation Protracted periods of BMV or poor technique (e.g., delivering breaths during the expiratory phase of the patient’s respiratory cycle; not maintaining an adequately open upper airway; or using excessive tidal volumes or positive pressure) can lead to insufflation of the esoph- agus and stomach. Gastric distention in turn presents two problems: • It predisposes to regurgitation of gastric con- tents, potentially leading to aspiration, with its sequellae. • Particularly in children, but also in adults, massive gastric distention can significantly elevate and interfere with movement of the diaphragm, in turn creating further difficulty with BMV by impacting respiratory system compliance. In extreme cases, gastric rupture can occur. OXYGEN DELIVERY DEVICES AND BAG-MASK VENTILATION 49 Gastric insufflation can be avoided by care- ful attention to delivered tidal volumes, employ- ing the lowest ventilation pressures possible (below 20 cm H 2 O), and using airway adjuncts such as the OPA and NPA. Evidence is emerg- ing that especially in the cardiac arrest patient, lower esophageal sphincter pressure decreases rapidly from the normal 20 cm H 2 O to as little as 5 cm H 2 O, underscoring the need to mini- mize applied insufflation pressures. 26 Applica- tion of cricoid pressure (see below) can also be considered. Although most patients can be ade- quately oxygenated and ventilated using good, well-timed BMV technique, some gastric insuf- flation is inevitable. BMV should therefore be viewed as a “bridging” procedure to be used for a limited period of time. If clinically significant gastric distention is suspected, an oro- or naso- gastric tube should be passed to decompress the stomach. Cricoid Pressure and BMV Posterior pressure on the cricoid cartilage com- presses the esophagus between the cartilagi- nous ring of the cricoid and the body of the C6 vertebra. It is often used to prevent passive regurgitation of gastric contents during rapid- sequence intubation, but can also be consid- ered in the unconscious patient during BMV to reduce inadvertent insufflation of air into the stomach, 27 as discussed above. However, it must be appreciated that cricoid pressure can cause difficulty with BMV, 28, 29 especially if applied at excessive pressures or in an upward direction. 30 If this is suspected, it should be at least tran- siently released, to determine if that is the cause of difficulty. “AutoPEEP” The patient with reactive airways disease experi- ences air trapping and difficulty with exhalation. In all patients, but particularly those with known or suspected air trapping disease, attention must be paid to allowing sufficient time for exhala- tion during BMV. Failure to do this may result in a buildup of intrathoracic pressure, which in turn risks both cardiovascular collapse and baro- trauma. Pressure may also be alleviated simply by intermittently releasing the seal made by the mask against the face. Cervical Spine Precautions and BMV BMV can be performed safely in the patient who is considered at risk for a cervical spine (C-spine) injury, for example, the unconscious trauma patient. However, radiologic studies have shown that movement of the C-spine with BMV is as much or more than that occurring with laryngoscopic endotracheal intubation. 31–34 As such, during BMV, manual in-line neck stabi- lization (MILNS) should be applied. Head tilt should be omitted: jaw lift is the only airway- opening maneuver that should be used. The Clinician with Small or Tiring Hands A one-person technique may be difficult or impossible for the clinician with smaller hands, or a clinician of average stature dealing with a very large patient. In such situations, early use of a two-person technique should be considered. Laryngospasm Laryngospasm is a tight and complete adduction of the vocal cords. It sometimes occurs in response to attempted airway manipulation in deeply sedated patients, and may be more common in the pediatric patient. Its effects can be dramatic, with an almost total inability to bag-mask venti- late the patient. If this is suspected, application of CPAP with the BVM device will often help break the spasm: simply continue to apply a tight 50 CHAPTER 4 seal with the mask, while maintaining light but continuous positive pressure on the bag. Severe or recalcitrant cases may require a small dose of skeletal muscle relaxant, for example, succinyl- choline 20 mg in the adult patient. ᭤ SUMMARY All clinicians with airway management respon- sibilities must be able to assess the critically ill patient for airway patency and adequacy of gas exchange. BLS protocols should be followed to open the airway, and if needed, positive-pressure ventilation with BMV instituted. BMV must be learned and practiced, and should not be looked upon as an easy skill. As the clinician becomes familiar with basic BMV, various adjuncts and additions to BMV can be used, such as PEEP and “pop-off” valves, depending on the prac- tice environment. A formal approach should be applied to the difficult BMV situation, and the predictors of difficult BMV appreciated. Faced with ongoing difficulty in performing BMV and/or intubation, the clinician should consider placing an extraglottic device such as a laryngeal mask airway or Combitube. REFERENCES 1. Dorges V, Wenzel V, Knacke P, Gerlach K. Com- parison of different airway management strategies to ventilate apneic, nonpreoxygenated patients. Crit Care Med. 2003;31(3):800–804. 2. Gausche M, Lewis RJ, Stratton SJ, et al. Effect of out-of-hospital pediatric endotracheal intubation on survival and neurological outcome: a controlled clinical trial. JAMA. 9, 2000;283(6):783–790. 3. Stockinger ZT, McSwain NE, Jr. Prehospital endo- tracheal intubation for trauma does not improve survival over bag-valve-mask ventilation. J Trauma. 2004;56(3):531–536. 4. Stapleton ER. Basic life support cardiopulmonary resuscitation. Cardiol Clin. 2002;20(1):1–12. 5. Martin PD, Cyna AM, Hunter WA, et al. Training nursing staff in airway management for resuscita- tion. A clinical comparison of the facemask and laryngeal mask. Anaesthesia. 1993;48(1):33–37. 6. Caples SM, Gay PC. Noninvasive positive pressure ventilation in the intensive care unit: a concise review. Crit Care Med. 2005;33(11):2651–2658. 7. Masip J, Roque M, Sanchez B, et al. Noninvasive ventilation in acute cardiogenic pulmonary edema: systematic review and meta-analysis. JAMA. 2005;294(24):3124–3130. 8. Mehta S, Hill NS. Noninvasive ventilation. Am J Respir Crit Care Med. 2001;163(2):540–577. 9. Confalonieri M, Garuti G, Cattaruzza MS, et al. A chart of failure risk for noninvasive ventilation in patients with COPD exacerbation. Eur Respir J. 2005;25(2): 348–355. 10. Templier F, Dolveck F, Baer M, et al. Laboratory testing measurement of FIO2 delivered by Boussi- gnac CPAP system with an input of 100% oxygen. Ann Fr Anesth Reanim. 2003;22(2):103–107. 11. Gabbott DA, Baskett PJ. Management of the airway and ventilation during resuscitation. Br J Anaesth. 1997;79(2):159–171. 12. Levitan R, Ochroch EA. Airway management and direct laryngoscopy. A review and update. Crit Care Clin. 2000;16(3):373–388. 13. Roberts K, Porter K. How do you size a nasopha- ryngeal airway. Resuscitation. 2003;56(1):19–23. 14. Stoneham MD. The nasopharyngeal airway. Assess- ment of position by fibreoptic laryngoscopy. Anaesthesia. 1993;48(7):575–580. 15. Muzzi DA, Losasso TJ, Cucchiara RF. Complication from a nasopharyngeal airway in a patient with a basilar skull fracture. Anesthesiology. 1991;74(2): 366–368. 16. Schade K, Borzotta A, Michaels A. Intracranial mal- position of nasopharyngeal airway. J Trauma. 2000;49(5):967–968. 17. Part 4: Adult Basic Life Support. Circulation. 2005;112(24_suppl):IV19–IV34. 18. Wenzel V, Idris AH, Montgomery WH, et al. Rescue breathing and bag-mask ventilation. Ann Emerg Med. 2001;37(4 Suppl):S36–S40. 19. Yildiz TS, Solak M, Toker K. The incidence and risk factors of difficult mask ventilation. J Anesth. 2005;19(1):7–11. 20. Davidovic L, LaCovey D, Pitetti RD. Comparison of 1-versus 2-person bag-valve-mask techniques for manikin ventilation of infants and children. Ann Emerg Med. 2005;46(1):37–42. 21. Langeron O, Masso E, Huraux C, et al. Prediction of difficult mask ventilation. Anesthesiology. 2000;92(5): 1229–1236. OXYGEN DELIVERY DEVICES AND BAG-MASK VENTILATION 51 22. Walls RM, Murphy M. Identification of the diffi- cult and failed airway. In: Walls RM, ed. Manual of Emergency Airway Management. 2nd ed. Philadelphia: Lippincott Willimas and Wilkins; 2004. 23. Morikawa S, Safar P, Decarlo J. Influence of the headjaw position upon upper airway patency. Anesthesiology. 1961;22:265–270. 24. Hillman DR, Platt PR, Eastwood PR. The upper air- way during anaesthesia. Br J Anaesth. 2003;91(1): 31–39. 25. Isono S, Tanaka A, Ishikawa T, et al. Sniffing posi- tion improves pharyngeal airway patency in anes- thetized patients with obstructive sleep apnea. Anesthesiology. 2005;103(3):489–494. 26. Gabrielli A, Wenzel V, Layon AJ, et al. Lower esophageal sphincter pressure measurement dur- ing cardiac arrest in humans: potential implications for ventilation of the unprotected airway. Anesthe- siology. 2005;103(4):897–899. 27. Wenzel V, Idris AH, Dorges V, et al. The respiratory system during resuscitation: a review of the history, risk of infection during assisted ventilation, respi- ratory mechanics, and ventilation strategies for patients with an unprotected airway. Resuscitation. 2001;49(2):123–134. 28. Palmer JHM, Ball DR. The effect of cricoid pressure on the cricoid cartilage and vocal cords: an endo- scopic study in anaesthetised patients. Anaesthe- sia. 2000;55(3):263–268. 29. Hocking G, Roberts FL, Thew ME. Airway obstruc- tion with cricoid pressure and lateral tilt. Anaes- thesia. 2001;56(9):825–828. 30. Hartsilver EL, Vanner RG. Airway obstruction with cricoid pressure. Anaesthesia. 2000;55(3):208–11. 31. Brimacombe J, Keller C, Kunzel KH, et al. Cervical spine motion during airway management: a cine- fluoroscopic study of the posteriorly destabilized third cervical vertebrae in human cadavers. Anesth Analg. 2000;91(5):1274–1278. 32. Aprahamian C, Thompson BM, Finger WA, et al. Experimental cervical spine injury model: evalua- tion of airway management and splinting tech- niques. Ann Emerg Med. 1984;13(8):584–587. 33. Donaldson WF 3rd, Heil BV, Donaldson VP, et al. The effect of airway maneuvers on the unstable C1-C2 segment. A cadaver study. Spine. 1997;22(11): 1215–1218. 34. Hauswald M, Sklar DP, Tandberg D, et al. Cervical spine movement during airway management: cinefluoroscopic appraisal in human cadavers. Am J Emerg Med. 1991;9(6):535–538. 52 CHAPTER 4 Chapter 5 Tracheal Intubation by Direct Laryngoscopy 53 • Cervical spine immobilization will often lead to an “epiglottis-only,” Grade 3 view during direct laryngoscopy. • To avoid patient morbidity, esophageal intubations must be immediately recognized and corrected. ᭤ INTRODUCTION This chapter will review direct laryngoscopy and intubation, including the initial response to encountered difficulty. Direct laryngoscopy (DL) is so named because it results ideally in direct line-of-sight visualization of the glottis (Fig. 5–1). While DL is only one method of facilitating defin- itive airway management, it is still the procedural standard for intubation in emergencies, and as such is deserving of a detailed discussion. Alter- native intubation techniques, including blind naso- tracheal intubation, are discussed in later chapters. ᭤ PREPARATION FOR ENDOTRACHEAL INTUBATION The adage that “your first shot is your best shot” is very applicable to laryngoscopy and intuba- tion. Prior to proceeding with any intubation, it is essential that the following preparations have been undertaken: ᭤ KEY POINTS • Direct laryngoscopy remains the proce- dural standard for emergency intubation. • The clinician should always psychologi- cally prepare for a difficult airway, in an attempt to “anticipate the unanticipated.” • Special attention must be paid to positioning the morbidly obese patient to facilitate direct laryngoscopy. • Cricoid pressure and external laryngeal manipulation (ELM) are two separate maneuvers done on two separate structures, for different purposes. • Failure to engage the hyoepiglottic liga- ment in the vallecula is a probable cause of the novice failing to achieve an ade- quate view during direct laryngoscopy. • Head lift, two-handed laryngoscopy and ELM represent three ways to use two hands on the fir s t intubation attempt (“3–2–1”). • Beware the “pseudolarynx,” especially in young children. • A tracheal tube introducer (“bougie”) or fiberoptic stylet can be used on the first intubation attempt when “best look” direct laryngoscopy has failed to yield an ade- quate view. Copyright © 2008 by The McGraw-Hill Companies, Inc. Click here for terms of use. A. Equipment should be assembled and imme- diately available for management of either a standard or unanticipated very difficult airway. If possible, this equipment should be pre- pared prior to the patient’s arrival. Ideally, a dedicated airway equipment cart with all the necessary tools, checked daily, should be a fixture in most acute-care areas. B. The patient and clinician performing the intubation should be positioned in the optimal (allowable) position for direct laryn- goscopy. C. The patient has been optimally preoxy- genated. D. Large-bore intravenous (IV) access has been obtained and a fluid bolus delivered, when appropriate. E. Drugs needed to facilitate airway manage- ment are available. Care should be taken to match the drug type and dosage with the patient and any acute or underlying chronic conditions. F. Personnel: Airway management is not a one-person job. At least one assistant is nec- essary to help, guided by specific directions. If problems are anticipated, this should be communicated to the team, and roles assigned before getting started. ᭤ EQUIPMENT FOR TRACHEAL INTUBATION A well-equipped airway cart is not useful unless it is at the bedside and its contents are familiar. The following mnemonic may be helpful to ensure that essential pieces of equipment are immediately available: STOP “I” “C” BARS. Suction—Rigid tonsillar suction is vital, turned on and placed in close proximity to the patient’s head. If there is a high likelihood of encountering copious amounts of blood or regurgitated matter, two running suctions are not excessive. The suction tubing must 54 CHAPTER 5 Figure 5–1. Direct laryngoscopy is so-named as it affords a direct line-of-sight view from the clinician’s eye to the laryngeal inlet. be connected to an appropriate wall unit. The rigid suction catheter should be checked to see if it has a thumb port that must be occluded to work effectively. Tubes—An appropriately sized endotracheal tube (ETT, e.g., adult female 7.0; adult male 8.0 internal diameter, [ID]) is prepared, as well as a tube a half or full size smaller. Rarely is a larger tube size required in an adult patient. A 10 cc syringe is attached to the pilot line, and the cuff integrity checked by fully inflating, then deflating it. The ETT tip can be lubricated with 2% lidocaine jelly or other water soluble lubricant. For all emer- gency intubations, a lubricated stylet should be inserted into the ETT. If a curved Mac- intosh blade is used, the stylet curve should not exceed the default curvature of the ETT. Alternatively, and in particular for a straight blade, a “straight to cuff” shape will be ben- eficial, whereby the tube is styletted straight, with a 25–35° upward bend placed just proximal to the cuff 1 (Fig. 5–2). For pedi- atric patients, the Broselow tape can be con- sulted for appropriate ETT sizing. Oxygen and positive pressure—A manual resuscitator with oxygen reservoir bag, attached to high flow O 2, should be avail- able. As the only source of positive pressure ventilation, this device should be checked by occluding the patient end with a finger and squeezing the self-inflating bag, feeling for the positive pressure thus developed. The reservoir bag should be distended. Pharmacology—All the drugs that could possi- bly be needed should be drawn up and labeled. This may include drugs needed for topical airway anesthesia, IV sedation, or rapid-sequence intubation (RSI), including induction agent and muscle relaxant. The armamentarium should always include an agent to treat postintubation hypotension— merely instituting positive pressure ventila- tion can interfere with venous return and TRACHEAL INTUBATION BY DIRECT LARYNGOSCOPY 55 Figure 5–2. “Straight to cuff” stylet preparation of the ETT (above) compared to natural curve (below). cause hypotension, particularly in the vol- ume-depleted patient. Intravenous access—Good IV access (ideally 18G or larger) should be in situ, free- flowing and not on a pump. It is rare that a patient will not benefit from a fluid bolus of 10–20 mL/kg prior to intubation. Connect to monitors and Confirmation—During intubation, the patient should ideally be mon- itored with an electrocardiogram (ECG) tracing, noninvasive blood pressure cuff (cycling at intervals of no longer than 3 minutes), and a pulse oximeter. In addition, objective means for confirming tracheal location of the ETT should be available, for example, capnometry and/or an esophageal detector device. Blades and Bougie—The laryngoscope should be checked for bright light intensity. Sev- eral blades should be available. The #3 Mac- intosh (curved) blade will be useful as a default blade, with the #4 for larger males. To those familiar with it, a straight blade (e.g., Miller, Phillips, or Wisconsin) can be a useful primary or alternative blade. A tra- cheal tube introducer (bougie) should be within easy reach during all emergency intu- bation attempts. Alternative intubation device—In addition to the bougie, during every emergency intuba- tion attempt, equipment for an alternative intubation technique should be available for immediate use. Examples include the LMA Fastrach TM (Intubating Laryngeal Mask Air- way [ILMA]), fiberoptic optical stylet, or Tra- chlight. These devices all require prepara- tion by someone familiar with their use. If the patient is being bag-mask ventilated with difficulty in between intubation attempts, the primary clinician will not be available to prepare this equipment. Rescue oxygenation technique—A Laryngeal Mask Airway (e.g., LMA Classic TM , ProSeal, Supreme, or Fastrach), Combitube, or other extraglottic device is useful as a rescue oxy- genation tool. One such device should be sized for the patient and within arm’s reach for the infrequent failed intubation or failed oxygenation (Chap. 12) situation. Surgical (i.e., cricothyrotomy) technique—For most intubations, simply knowing the equip- ment’s location and how to use it is adequate preparation. However, for anticipated very difficult situations, it may be appropriate to have this equipment out and opened: a com- ponent of the so-called “double set-up”. ᭤ POSITIONING FOR LARYNGOSCOPY AND INTUBATION The clinician should be optimally positioned before an intubation attempt, as should the patient. Clinician Positioning Comparisons of the posture of experienced and novice laryngoscopists have observed the fol- lowing: experienced clinicians stand further back, with straighter backs and arms, 2 and hold the laryngoscope closer to the base of the blade 3 (Fig. 5–3). During direct laryngoscopy, the laryngoscopist’s arm should be only mod- estly flexed at the elbow and adducted, and not bent at right angles and abducted. Better mechan- ical advantage is then developed by the applica- tion of a more in-line axial force through the arm to the handle of the laryngoscope. Once a view of the laryngeal inlet is obtained, some clinicians elect to keep the arm adducted against the trunk for additional support. This position of the arm is consistent with the optimal distance from the laryngoscopist’s eye to the patient’s glottis of approximately 16–18 inches. Attention to clinician positioning may help deliver favorable mechanical and visual advantage during laryngoscopy. Patient Positioning Three aspects of patient positioning are crucial. Failure to observe these positioning principles may make obtaining a good view at laryn- goscopy more difficult. 56 CHAPTER 5 A. “Up-down,” referring to stretcher height. Often overlooked, the patient should be at the appropriate height—with the middle of the patient’s head at the level of the clinician’s belt buckle. B. “North-south”: the patient’s head should be positioned as close as possible to the upper (“north”) end of the stretcher. C. “Sniff,” that is, head and neck positioning. Classic teaching suggests placing the head TRACHEAL INTUBATION BY DIRECT LARYNGOSCOPY 57 Figure 5–3. Clinician positioning during direct laryngoscopy: relatively straight back; modestly flexed, adducted elbow, and a grip on the laryngoscope handle close to the blade. and neck in the “sniffing” position for direct laryngoscopy. When not contraindicated by C-spine precautions, this involves flexing the neck at the cervico-thoracic junction, with extension of the neck at the upper few cervical vertebrae and head at the occipito- cervical junction. This will help align airway axes, in turn helping attain a direct line-of- sight view from the clinician’s eye to the laryn- geal inlet (Fig. 3–8, Chap. 3). The sniffing position can be attained by placing folded blankets (about 4”/8 cm high) under the patient’s occiput and/or lifting the head dur- ing laryngoscopy, using the right hand under the occiput. The axis alignment sought by placing the patient in the sniffing position can be exter- nally referenced. Observing the patient from the side, when the external auditory meatus is lined up horizontally with the sternal notch, the patient is generally well positioned for laryn- goscopy in a good “sniff” position (Figs. 5–4 A and B). This same “ear-to-sternum” positioning 58 CHAPTER 5 Figures 5–4. In contrast to the positioning of the patient in the neutral position (A), a line drawn from the external auditory meatus to the patient’s sternum (“ear to sternum” line) will give a rough indication of good positioning for direct laryngoscopy (B). A B [...]... cardiac output) The presence of exhaled CO2 will be indicated by a change in color, for example, from purple to yellow (Fig 5– 23) Continuously reading capnographs are being used increasingly in out-of-operating room (OR) environments, using infrared spectrometry to measure and display carbon dioxide concentration in inspired and expired gas This enables monitoring of mechanical ventilation and procedural... POSITIONING IN SPECIAL SITUATIONS C-Spine Precautions In the patient requiring C-spine precautions, the sniff position is not an option DL under these conditions will be more difficult, with an expected incidence of blind, Grade 3 views (no part of the glottis visible) of 20%–25%10 with application of manual in- line neck stabilization (MILNS) The incidence of Grade 3 views increases to 50% or more10, 11... help maintain the view during ETT placement Head Lift Performing a head lift during laryngoscopy, when not contraindicated by C-spine precautions, may improve the view of the laryngeal inlet.8,9 During laryngoscopy, the clinician’s right hand is placed under the occiput and lifts the head upwards, keeping the face parallel to the floor (Fig 5–27) This increases lower neck flexion, while also increasing... clinicians are adept at blindly “hooking” a styletted ETT under the epiglottis in the Grade 3 situation, use of the bougie holds the following advantages: • Relative to the size of the glottic opening, the bougie is smaller in diameter than an ETT, increasing chances of successful blind tracheal access • Following blind passage, tactile feedback is transmitted from the bougie to the clinician’s fingers,... framing the inlet inferiorly End-Tidal Carbon Dioxide (ETCO2) Detection ETCO 2 detection to confirm endotracheal intubation has rapidly become a standard of care in emergency airway management The technique provides a simple and inexpensive method of confirming correct endotracheal, as opposed to esophageal tube placement A disposable CO2 detector is simply placed in- line at the ETT connector (in the... this reason, during attempts at laryngoscopy and intubation, MILNS should be substituted for the cervical collar, as the latter increases difficulty by also interfering with mouth opening Note that the function of in- line stabilization is as a reminder to the laryngoscopist to minimize movement, not necessarily to preclude any movement whatsoever 59 Morbid Obesity Airway management in the morbidly... This two-handed approach, although rarely needed, helps in applying the appropriate lifting force, and tends to promote traction in the appropriate direction, along the long axis of the laryngoscope handle, thus decreasing any tendency to lever the laryngoscope Once the view of the glottic opening is attained, the left arm can be adducted against the clinician’s trunk to help maintain a lifting force... TRACHEAL INTUBATION BY DIRECT LARYNGOSCOPY desaturate quickly when rendered apneic, for example, during an RSI The Patient in Extreme Respiratory Distress The acutely dyspneic patient will not tolerate the supine position If an awake intubation is 61 planned, the patient can be intubated in the sitting or semisitting position using DL or other intubation technique In this situation, the clinician may... expansion and auscultated following intubation, generally speaking, this should not be relied upon to confirm endotracheal intubation. 23 For example, in the scenario where a patient has been intubated via an “awake” technique using topical airway anesthesia, the spontaneously breathing patient may continue to have breath sounds and chest expansion, even in face of an esophageal intubation Auscultation is... cartilaginous rings and the carina, as seen though a fiberoptic bronchoscope passed down an endotracheal tube 76 • • • • • • CHAPTER 5 useful, as long as this limitation is appreciated, but should be used mainly to rule out right mainstem intubation or previously missed pneumothorax Increasing oxygen saturation In a well preoxygenated patient, oxygen desaturation following apnea can take up to 8 minutes In . occipito- cervical junction. This will help align airway axes, in turn helping attain a direct line-of- sight view from the clinician’s eye to the laryn- geal inlet (Fig. 3 8, Chap. 3) . The sniffing position. cervical spine injury model: evalua- tion of airway management and splinting tech- niques. Ann Emerg Med. 1984; 13( 8):584–587. 33 . Donaldson WF 3rd, Heil BV, Donaldson VP, et al. The effect of airway. contention by suggest- ing the utility of a head lift 8,9 in improving laryn- geal view. ᭤ POSITIONING IN SPECIAL SITUATIONS C-Spine Precautions In the patient requiring C-spine precautions, the