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An Evaluation of McCoy Balloon Laryngoscopy in Patients With Moderate-to-Major Endotracheal Intubation Difficulty

Mentzelopoulos, Spyros D., MD, PhD, DEAA; Tzoufi, Maria, MD, DEAA; Rellos, Kostas, MD, PhD; Michalopoulos, Argyris S., MD, FCCM, FCCP; Stamataki, Elissavet, MD, PhD, DEAA; Roussos, Charris, MD, PhD; Zakynthinos, Spyros G., MD, PhD

doi: 10.1213/01.ane.0000171716.20536.96
General Articles: Research Report
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We hypothesized that combined McCoy-balloon laryngoscopy may facilitate airway management relative to McCoy or balloon laryngoscopy. In 10 anesthetized/paralyzed patients with prior intubation difficulty scale scores of >5, McCoy-balloon laryngoscopy versus conventional/balloon/McCoy laryngoscopies resulted in greater laryngeal aperture exposure (2.3 ± 0.6 versus 0.6 ± 0.2/1.4 ± 0.4/1.5 ± 0.6 cm2, respectively), lower intubation difficulty scale score (0.00 (0.00–0.00) versus 6.00 (6.00–8.25)/1.50(0.00–4.00)/2.00(0.75–5.00), respectively, median [interquartile range]), and 9%–74% shorter time to intubation confirmation (P < 0.05–0.001 for all). Balloon and McCoy laryngoscopies improved laryngoscopic/intubating conditions relative to conventional laryngoscopy. In patients with moderate-to-major conventional airway management difficulty, McCoy-balloon laryngoscopy further improves laryngoscopic/intubating conditions.

IMPLICATIONS: This study shows that, in patients with moderate-to-major conventional airway management difficulty, combined McCoy-balloon laryngoscopy results in improved laryngoscopic/intubating conditions when compared with the conventional, McCoy, and balloon laryngoscopic techniques. McCoy-balloon laryngoscopy combines the merits of McCoy and balloon laryngoscopy and can be recommended for patients with moderate-to-major intubation difficulty.

Departments of Intensive Care Medicine Henry Dunant General Hospital and Evaggelismos General Hospital, Athens, Greece.

Accepted for publication April 28, 2005.

Address correspondence and reprint requests Spyros D. Mentzelopoulos, MD, PhD, DEAA, 12 Ioustinianou Street, GR-11473, Athens, Greece. Address electronic mail to sdm@hol.gr.

In emergency departments, conventional laryn-goscopy-guided endotracheal intubation will be initially attempted in most patients with high (>5) intubation difficulty scale (IDS) scores (1,2). McCoy and balloon laryngoscopic techniques improve laryngoscopic/intubating conditions relative to conventional laryngoscopy (3–7). Recent experience suggests that combined McCoy-balloon laryngoscopy may further facilitate difficult airway management (8,9). Thus, we tested the hypothesis that McCoy-balloon laryngoscopy results in improved laryngeal aperture (LA) exposure and reduced IDS score relative to conventional, McCoy, and balloon laryngoscopy.

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Methods

After IRB approvals were obtained, IDS scores were determined for 1790 emergency intensive care unit (ICU) admissions. Orotracheal tube (OTT)-guide use was considered as “alternative intubation technique” (2,7). Each emergency intubation was accomplished by one physician-operator using a Macintosh blade (2). “Clinically stable, not ready-for-weaning” ICU patients with tracheostomies (performed during ICU stay) and admission IDS scores >5 (moderate-to-major intubation difficulty) (2) were considered for study enrollment.

Informed patient/next-of-kin consent was obtained, and anesthesia and neuromuscular blockade were induced and maintained with propofol/fentanyl and cisatracurium, respectively. Four consecutive orotracheal intubations were performed by one of three experienced operators (7), who used four laryngoscopic techniques in random order. Before each laryngoscopy, the patient’s head was placed in the standard intubating position (35° lower neck flexion and 15° plane-of-face extension relative to horizontal) by using an angle finder (7,10,11). Face plane was defined by straight lines passing through the supraorbital, infraorbital, and mental foramina (10). Laryngoscopies were performed with number 4 standard and modified Macintosh and McCoy blades. Fogarty catheters were secured on the modified blades with transparent, adhesive dressing (Tegaderm™; 3M Health Care, St. Paul, MN). Conventional, balloon, McCoy, and McCoy-balloon laryngoscopies were performed as routinely and previously described (4,6–9) (Fig. 1). Forty-five seconds were allowed for each laryngoscopy before attempting intubation. During laryngoscopy, the laryngoscope handle-to-horizontal angle was kept at 15°–20° and the light source-axis-to-horizontal angle at 40°–45° (7). External laryngeal manipulation was allowed whenever the posterior glottis or less was exposed. Laryngoscopic findings were videotaped with a camcorder (Handycam CCD-TRV 65E; Sony, Tokyo, Japan) (7) connected to a television monitor for continuous laryngoscopic procedure display.

Figure 1.

Figure 1.

After LA recordings, the tracheostomy tube was withdrawn, and 45 s was allowed to confirm (visually or by end-tidal CO2 monitoring) the passage of an OTT (internal diameter, 7.0–8.0 mm) through the vocal cords. The time needed for laryngeal view optimization and successful/confirmed orolaryngeal/orotracheal intubation was defined as time to intubation confirmation. After intubation confirmation, the OTT was withdrawn, and a new tracheostomy tube was inserted into the trachea and ventilation resumed.

Laryngoscopic views and intubation difficulty were graded by the laryngoscopist and independent observers (7). Ideal intubation corresponded to an IDS score of 0 (2,7). Table 1 displays criteria for study protocol termination and/or patient data rejection. Exposed LA-area measurements were conducted as previously described (7) (Fig. 2).

Table 1

Table 1

Figure 2.

Figure 2.

LA-area values and intubation times were compared with repeated measures analysis of variance, followed by Scheffé test as appropriate. IDS scores were compared with Friedman’s exact test. Significance was set at P < 0.05. Data are presented as mean ± sd or median (interquartile range).

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Results

The data from 10 patients (7 male, 3 female; age, 66 ± 14 yr; body mass index, 23.8 ± 1.6 kg/m2) were analyzed. Relative to conventional/balloon/McCoy laryngoscopies, McCoy-balloon laryngoscopy resulted in larger LA exposure and lower IDS score (P < 0.001-0.05). Relative to conventional laryngoscopy, balloon and McCoy laryngoscopies resulted in larger LA exposure and lower IDS score (P = 0.002-0.007). Balloon and McCoy laryngoscopies provided similar laryngoscopic/intubating conditions. Individual LA-area data and IDS scores are provided in Table 2 and Table 3, respectively. Representative laryngoscopic images are provided in Figure 3. Time to intubation confirmation was longest with conventional laryngoscopy (36 ± 4 s), intermediate/similar with balloon and McCoy laryngoscopies (18 ± 7 and 21 ± 8 s, respectively) and shortest with McCoy-balloon laryngoscopy (11 ± 2 s) (P < 0.001-0.05).

Table 2

Table 2

Table 3

Table 3

Figure 3.

Figure 3.

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Discussion

Our main findings are that in patients with moderate-to-major intubation difficulty (2), combined McCoy-balloon laryngoscopy results in superior laryngoscopic/intubating conditions relative to the conventional/balloon/McCoy laryngoscopic techniques. In patients with difficult conventional laryngoscopy-guided intubation, the Macintosh blade contour may not adequately conform to an abnormal upper airway contour (9,12,13). Thus, the hyoid/tongue base and epiglottis cannot be lifted and the LA cannot be visualized (7). The McCoy-balloon blade is a balloon-tipped McCoy blade-modification (8,9). By combining an inflatable balloon with a hinged tip (4,8,9), this blade exhibits enhanced contour adjustability compared with all the other three laryngoscope blades we used. Consequently, the probability of blade contour conformation to upper airway contour and of effective epiglottis lifting/LA exposure is maximized.

The number of supplementary attempts at intubation (N1) was a major determinant of the differences in IDS scores/intubation times. Each supplementary attempt generated the need for use of OTT guide, or external laryngeal pressure, or (subjectively) (2) increased lifting force. The sums of individual N1s were 28, 9, 12, and 1 with conventional, balloon, McCoy, and McCoy-balloon laryngoscopies, respectively, reflecting successful intubation after an average of 3.8, 1.9, 2.2, and 1.1 attempts, respectively.

Fewer supplementary attempts and shorter intubation times indicate reduced probability of upper airway trauma (7,14). More rapid intubation indicates reduced time of airway management-related apnea and associated hypoxemia risk. Thus, McCoy-balloon laryngoscopy may be particularly useful in patients with acute respiratory failure (ARF) who require emergency ventilatory support.

Study participants were intubated 4 times for no therapeutic purpose. However, study results (Table 3) indicated that any future emergency/elective McCoy-balloon laryngoscopy-guided orotracheal intubation would most likely be ideal and, consequently, safer. Also, seven patients were admitted for ARF as a result of obstructive lung disease exacerbation; in such patients, severe disease exacerbations necessitating ventilatory support recur frequently after ICU/hospital discharge (15–19).

As previously (7–9,11,20,21), we used number 4 blades because their use tends to limit the extent of laryngoscope blade levering motion (11). The 15°–20° degree handle-to-horizontal angle resulted in minimal laryngoscope blade levering motion/upper incisor trauma-risk (7,10,11), i.e., correct (and not disadvantageous) (Tables 1 and 3) laryngoscopic technique (7).

In conclusion, McCoy-balloon laryngoscopy substantially facilitates orotracheal intubation in patients with high IDS scores. Consequently, we recommend the use of McCoy-balloon laryngoscopy in difficult airway management.

The authors thank physiotherapist Mr. C. Gregoriades for his valuable help with the laryngeal view recordings.

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References

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