Supraglottic and Extraglottic Airways (SGAs and EGAs)

LMAs

CLINICAL SKILLS FOR THE PREHOSPITAL USE OF THE LMA Similar to the first laryngoscopy,41 the first LMA insertion attempt should be optimized. Is the Correct LMA Size Selected? The LMA Classic is available in six sizes. The manufacturer recommends two size selection criteria: weight based (for adults patients: size 3, 30 to 50 kg, size 4, 50–70 kg, size 5, 70–100 kg, and recently size 6 for >100 kg) and gender based (size 4 for female and size 5 for male adults). The manual also recommends that clinical judgment should be used in selecting the size. Is the LMA Ready to Use? The device is prepared (deflation and lubrication of the dorsal surface with a water soluble lubricant), stored, and used in an uncontrollable and unpredictable environment. The LMA, water soluble lubricant and a syringe should be packaged together. The disposable LMA-Unique (sizes #3, #4, and #5) (LMA North America, San Diego, Calif.) offers this advantage. Is the Patient Ready to Accept the LMA? Insertion of the LMA during inadequate level of anesthesia is a common mistake. A patient who is not “deep enough” (gagging, coughing …) will fight the LMA insertion and discourage the rescuer from inserting the index finger deep into the mouth resulting in misplacement of the device. A misplaced LMA is more likely to be dislodged or to trigger reflexes (laryngospasm, glottic closure, vomiting, or hiccups).42 In the OR the loss of motor response to the “jaw thrust” is considered more reliable to assess adequate “depth” than the loss of verbal contact with the patient.43 Unwanted effects of the jaw thrust may include cervical spine mobilization and stimulation of the patient. Optimal Insertion of the LMA The rescuer will insert the LMA in variable positions: standing (emergency room), kneeling (scene, ambulance), sitting (helicopter), and from the patient’s side

(difficult extrication). Experienced anesthesiologists need at least 2 cm distance between the upper and the lower incisors to insert the LMA.44 The kneeling position is suboptimal for the ETT placement but advantageous for the LMA insertion. The standard index finger technique is used when standing or kneeling at the patient’s head. This technique is superior to any other insertion techniques.45 The thumb technique is useful when the victim is trapped (motor vehicle crash) or difficult to reach from above the head. The rescuer standing by the side of the patient will use the thumb of the dominant hand that substitutes the index finger to guide the LMA along the palato-pharyngeal path. The insertion success rate of the thumb technique is lower than the index finger technique.46 The most common error made during the early learning phase with the standard technique is the insertion of the LMA straight into the mouth without using the hard palate as a slide and with the index finger not inserted deep enough into the mouth, misplacing the LMA. Other reasons for failure are: choice of wrong LMA size, incomplete cuff deflation, inability to get the mask past the teeth, inability to advance the cuff past the base of the tongue, insufficient air, or overinflation of the LMA cuff.47 An automated voice advisory manikin may correct these predictable mistakes.48 Neutral head position, CP, and MILS can complicate the LMA insertion. Insertion of the LMA should be attempted with the anterior half of the cervical collar removed and MILS applied. Brimacombe recommends that LMA insertion with CP applied should be attempted only if the oxygen saturation (SpO2) is >95%. If insertion fails, CP should be released for the second attempt. If the SpO2 is <95% initial insertion should be with CP released as ventilation/oxygenation is more important than preventing aspiration.13 Optimal Cuff Inflation Inflate the cuff with two-thirds of the maximum volume recommended (marked on the LMA tube), then, add 3 to 5 mL of air, as needed up to the maximum volume recommended. A rigid over inflated cuff will loose its ability to mold on the soft periglottic tissues: over inflation will not compensate for malposition but will further compromise the seal and the use of PPV. The manufacturer recommends the use of a pressure gauge for optimal cuff inflation. All current literature pertinent to supraglottic airway devices (SGD) standardizes cuff inflation pressure to 60 cm H2O. LMA Ventilation Pharyngeal and esophageal leaks are expected with airway pressure over 20 cm H2O. Overzealous ventilation with no airway pressure monitoring can lead to a “misperceived” leak in an otherwise correctly placed LMA. Chest movement with small TV may be difficult to evaluate in a dressed victim, with chest trauma or strapped chest. Auscultation (chest, neck, and epigastrum) with small TV in a noisy environment may be deceiving. The use of the inflatable bulb (esophageal detector device) with the LMA is discouraged.49 In the OR the most specific test to detect LMA misplacement (defined fiberoptically) was the ability to generate airway pressure of 20 cm H2O without a leak whereas, the ability to ventilate manually (movement of the chest, condensation of expired gases, adequacy of expired gas volume and the feel of the bag) had the highest overall accuracy. Is the Patient Ready for Transport? Tape the LMA firmly in the midline to the upper jaw without bending the tube toward the forehead; keep the LMA tube in a neutral position (bended toward the chin) being vigilant not to dislodge the device during transport or manipulation of the resuscitation bag. A bite block will increase the device’s stability.50 Asai et al. considers that although CP applied after correct placement of the LMA significantly decreases the incidence of gastric insufflation, it also decreases the adequacy of ventilation.51 Ventilation should be reassessed after the application of the anterior cervical collar. If monitored, the airway pressure should be kept under 20 cm H2O. Regurgitation in the LMA Tube Brain considers the LMA cuff protective by filling the pharyngeal space otherwise filled with aspirate and should not be removed; also the LMA tube represents a path of minimal resistance, an alternative to the trachea.52 In the event of regurgitation/aspiration disconnect the breathing tube and allow regurgitated material to drain, and then gently ventilate using small tidal volumes (TV) with 100% Fio2. Place the patient with cervical spine precautions in Trendelenburg position. Sedate and/or paralyze the patient that is “too light.” Oxygenation should be maintained during the incident. Suction the LMA tube. There is no predictable continuum between the LMA tube and the glottic opening.53 A suction catheter will most likely not penetrate the trachea (for the same reason rescue medications administered through the LMA will not reach consistently the trachea). If the LMA fails (reduced chest wall movement, deteriorating O2SAT and ETCO2, increased airway pressure) other airway management options should be considered.   LMA Seal Breakdown 25 cm H20 BVM 100 Combitube 45   Incredibly low aspiration rate when LMA used for general (Anaes 2009;64:1289)   opening pressure ~21 with LMAS (21 J.F. Heuer, M. Stiller and J.Rathgeber et al., Evaluation of the new supraglottic airway devices Ambu AuraOnce and Intersurgical I-gel. Positioning, sealing, patientcomfort and airway morbidity, Anaesthesist 58 (2009), pp. 813–820   Inflate LMAs to less than 44 mmHg (60 cm H20)  

Sizing

Evaluation of the LMA Supreme™: A Sizing and Troubleshooting Study * Allan J. Goldman, M.D., Daniel Langille, C.R.N.A., Peter Freund, M.D., Michael Flacco, M.D.Department of Anesthesiology, University of Washington Medical Center, Seattle, Washington Introduction: The LMA Supreme(TM) (SLMA) is a new disposable supraglottic airway, which combines the features of the LMA Proseal(TM) (gastric access tube) and Fastrach(TM) (fixed curve shaft). All LMA manufacturers’ sizing recommendations are based upon patient weights. Early in our SLMA evaluation, we experienced occasional failures using those weight guidelines. We then observed that the shape and length of the SLMA fixed curve shaft is similar to a Guedel oral airway [fig. 1]. We proposed that using an oral airway-sizing guide might offer a better method for selecting the correct SLMA size. A secondary outcome from our sizing study was identifying which maneuvers improved the SLMA’s fit. Method: We prospectively collected insertion data from 100 patients. After a propofol induction, we waited till there was lack of response to a jaw thrust before inserting the SLMA. The SLMA size was chosen according to traditional oral airway size selection (angle of jaw to corner of the mouth). 80 mm oral airway = #3 Supreme 90 mm oral airway = #4 Supreme 100 mm oral airway = #5 Supreme If the choice was between two sizes, we chose the smaller device. If after inserting and taping the SLMA in place, the fixation tab was pressing on the upper lip, we then changed the SLMA to the next bigger size. A proper fit was determined to be [1]: fixation tab .5-2.5 cm from upper lip, tidal volume > 8ml/kg, oropharyngeal leak pressure > 20 ml/kg, and a positive suprasternal notch test [2]. If the fit was poor, one of the following maneuvers was performed: deeper insertion, an up-down maneuver (slowly withdrawing the inflated mask 5-6cm and reinserting) [3], or exchanging the device for a different size. Results: Size #3 was chosen for women 77% of the time, and size #4 was chosen for men 77% of the time (table 1). In the remainder of patients, the next larger size was chosen. In 5 patients (5%) the device was removed and exchanged for another size (table 1). The SLMA was an effective airway in all patients in this study. The up-down maneuver gave a better fit in 27% of the patients.   ~ The rigid connection of the respiratory gas tubing(with respect to the bowl of the mask) is the culprit behindthe inability to get the mask fully around the corner,as evidenced by the success with the LMA Unique.The connection between the respiratory gas tubing andthe bowl of the mask needs to flex (to a variable degree,depending on the patient’s anatomy) for the final phaseof LMA insertion to be complete. Solution? Mac 3 toelevate the base of tongue and flatten the “angle of attack”to mask insertion. Mac 3…. the ultimate tonguedepressor for the most Supreme airway. James DuCanto, MD Systematic Review of advantages of LMA over ETT and Facemask (Can J Anaesth 1995;42(11):1017)

Troubleshooting Article by Osbourne

ILMA

· Lubricate the tip of the tube. · Hold et tube at black line and insert and withdraw until lube on tube is totally spread, so there is no resistance. · Lift and tilt back on handle until minimum air leak when ventilating, this is the position the tube should be passed in.  

ILA

Klein Maneuver

Pull back a few cm, jaw thrust, push forward  

Chandy Maneuver

The Chandy maneuver (Figure 2) was developed by Dr. Chandy Verghese and significantly improves the effectiveness of the ILMA (25). It incorporates two maneuvers that improve lung ventilation and tracheal intubation using the ILMA. Part one of the Chandy maneuver facilitates positioning of the ILMA in the upper airway so that lung ventilation is maximized through the device. This is done by grasping the ILMA by the handle and moving it back and forth in the sagittal plane while observing the patient’s tidal volume and/or the capnographic waveform (if ventilation is being controlled manually). However, if the patient is breathing spontaneously, an airway whistle (e.g., Patil intubation guide [Anesthesia Associates, San Marcos, CA] or Beck Airway Airflow Monitor [Great Plains Ballistics, Lubbock, TX]) can be attached to the proximal portion of the ILMA to optimize ventilation through it. The whistle will sound with each breath the patient takes. The ILMA is then moved slowly back and forth in the sagittal plane using part one of the Chandy maneuver until maximal whistling is attained. Maximal whistling indicates optimal positioning of the ILMA. The second part of the Chandy maneuver involves aligning the ILMA to facilitate smooth passage of the endotracheal tube (ETT) into the trachea. A special Euromedical ETT is provided with the ILMA. The ETT has a longitudinal line, which should be oriented to face the patient’s nose superiorly. Proper orientation of the longitudinal line causes the ETT to exit the ILMA at an angle that eases its passage into the trachea. The ETT also has a circumferential line at a distance from the distal tip of the ETT that is equal to the length of the ILMA from the proximal to the distal port. At the point where the circumferential line is advanced to the proximal port of the ILMA, the distal tip of the ETT will be in contact with the epiglottic elevator bar (which covers the distal port of the ILMA). The epiglottic elevator bar raises the epiglottis so that the ETT can enter the glottis unimpeded. Just before the distal tip of the ETT contacts the epiglottic elevator bar, the second part of the Chandy maneuver is performed. This involves lifting the handle of the ILMA at a 45° angle to the patient’s chest. This helps align the trajectory of the ETT into the trachea inferiorly and usually facilitates smooth passage of the ETT into the trachea. If the patient is breathing spontaneously, an airway whistle attached to the proximal end of the ETT will sound with each ventilation. As the tip of the ETT enters the trachea, the volume of the whistle increases. When the cuff of the ETT is inflated, the volume of the whistle will increase even more, heralding the sealing of the ETT within the trachea and securement of the patient’s airway. Tracheal intubation should always be confirmed with an evidence-based method, using a carbon dioxide detector if the patient has a perfusing cardiac rhythm or a self-inflating bulb if the patient does not have a perfusing cardiac rhythm (39). Additionally, auscultation of bilateral breath sounds will confirm that the ETT is lying in a midtracheal position. The ILMA can then be removed over the ETT using the stabilizing rod (Figure 1) or left in place with the mask deflated until the trachea is extubated. (Proc Bayl Univ Med Cent 2005 July; 18(3): 220–227. James M. Rich, CRNA, MA)   The two steps of the Chandy maneuver. (a) After insertion of the LMA-Fastrach, optimal ventilation is established by slightly rotating the device in the sagittal plane, using the metal handle, until the least resistance to bag ventilation is achieved. This helps to align the internal aperture of the device with the glottic opening, (b) Just before blind intubation, the LMA-Fastrach is slightly lifted (but not tilted) away from the posterior pharyngeal wall using the metal handle. This prevents the endotracheal tube (ETT) from colliding with the arytenoids and facilitates the smooth passage of the ETT into the trachea. Reprinted from reference 25 with permission. The ABC of the LMA The LMA needs no introduction as a supraglottic device for airway control. It exists in a variety of designs, safe and successful use of which can be enhanced by well practiced use of the following manoeuvres that can easily be remembered as the ABC of the LMA. A is the Archie Manoeuvre, or the up-down manoeuvre. After LMA insertion, the apex of the mask can occasionally “down fold” the epiglottis, or rarely the tip of the mask folds back on itself, both resulting in airway obstruction. The manoeuvre involves withdrawing the LMA by 5cm followed by reinsertion. This has a high first time success rate of relieving airway obstruction by correcting both of these occurrences. B is the Bailey Manoeuvre. This technique allows extubation under deep anaesthesia by substituting an oral endotracheal tube for an LMA. The LMA is inserted over the ET tube, and the cuff is inflated. The cuff on the ET tube is then deflated and the tube is removed. The manoeuvre allows the LMA to maintain the airway during emergence with minimal stimulation, avoiding the coughing and bucking that is often undesired after certain surgical procedures. C is the Chandy manoeuvre. This 2 stage technique is used to increase the first time success rate of tracheal intubation with an ILMA by aligning the internal aperture of the device with the glottic opening. After the ILMA is inserted, the first part of the manoeuvre is to grasp its handle and rotate it in a saggital plane until optimal ventilation is achieved. The second part involves lifting the device to an angle of 45 degrees to the patients’ chest, aligning the distal aperture of the device with the trachea.   For blind placement, 1 study indicates that Fastrach is better than Air-Q (Anaesthesia 2011;66:185) Pressures of 20 mbar did not cause esophageal inflation with LMAs 40 and 60 did (Br J Anaesth. 2012 Sep;109(3):454-8.)

King LT/Laryngeal Tube Airways

sort of of a simplified combitube (Brit Journal Anaes 2005;95(6):729)

1. Insert connector to teeth
2. add 10-20 cc of air
3. pull back until good compliance
4. add 30- 40 cc of air
5. secure

Provision of ventilation while bronching through Intubating EGA