The Utility of Three-Dimensional Computed Tomography in Unanticipated Difficult Endotracheal Intubation

Ultrasound-based assessment of tongue thickness for prediction of difficult laryngoscopy and intubation

Background and Aims

Predicting difficult airway and preparedness for the same can help prevent catastrophic situations while handling the airway. With the increasing familiarity of anaesthesiologists to the use of ultrasound machine and its easy availability and non-invasiveness, we sought to study its utility in airway assessment, by measuring the thickness of tongue, to predict difficult laryngoscopy and intubation.

Material and Methods

A total of 85 patients undergoing elective surgeries under general anaesthesia with endotracheal intubation were examined preoperatively. Tongue thickness was measured using submental ultrasonography in the median sagittal plane along with other tests of airway assessment. Cormack Lehane grade on laryngoscopy and Intubation Difficulty Scale Score was recorded. The sensitivity, specificity, positive and negative predictive value, and accuracy was calculated for tongue thickness for predicting difficult intubation.

Results

The tongue thickness in those with difficult intubation (4.83 ± 0.62) was significantly higher than those without difficult intubation (4.38 ± 0.65). The ratio of tongue thickness to thyromental distance was also significantly higher in difficult intubation group. The area under the receiver operating characteristic curve for predicting difficult laryngoscopy and intubation was higher for tongue thickness as compared to other clinical parameters. The sensitivity and specificity of tongue thickness to predict difficult laryngoscopy was 100% and 83%, respectively, and to predict difficult intubation was 72% and 59%, respectively, with an accuracy of 72%.

Conclusion

Ultrasound based assessment of tongue thickness can be a useful predictor of difficult airway along with clinical assessment of the airway.

Navigating Goals of Care While Confronting an Urgent, Difficult Intubation: A Case Report

Urgent airway management is challenging because time constraints limit thorough evaluation and planning before endotracheal intubation. In this report, we describe a case in which an airway history review revealed extraordinarily complex airway anatomy that led to a decision not to attempt intubation in a man with end-stage chronic obstructive pulmonary disease. We emphasize the utility of reviewing history and imaging before attempted urgent intubation. We discuss the importance of a multidisciplinary approach that includes the patient, their family, and consultants when high-risk intubation is contemplated. The ethical role of the anesthesiologist is also discussed.

Management of tracheal deformity during intubation: a case report

Failure or difficulty in intubating the trachea can be either due to inability to visualize the glottis or some pathology at the level of or below the cords. This report describes a case of difficult intubation suspected of being related to neck scarring from previous surgery. Computed tomography (CT) was used to evaluate the patient's airway and revealed upper tracheal angulation. We describe a method to secure the airway in this patient with a two-person technique by rotating an oral endotracheal tube 180 degrees counterclockwise to adjust to the curvature of the trachea. Problems with intubation should be anticipated in patients with scarring of the neck, and equipment for aiding intubation should be on hand. Furthermore, we found that CT contributed to the assessment of the difficulty of intubation in this kind of patient.

Unanticipated Difficult Endotracheal Intubations in Patients with Cervical Spine Instrumentation

We present two cases of unanticipated difficult airway in patients requiring reoperation after cervical spine instrumentation. In both cases, the upper airway examination was normal, and fiberoptic-guided intubation proceeded with the patient sedated and breathing spontaneously. Cord visualization was difficult, but the scope was eventually advanced into the trachea and the endotracheal tube placed safely. Later review of radiographs showed the previously unrecognized protrusion of cervical hardware into the meso- and hypopharynx. We recommend that anesthesiologists review recent radiographic studies for potential airway compromise before approaching the airway of patients presenting for revision of cervical instrumentation.

The cuff-leak test is a simple tool to verify severe laryngeal edema in patients undergoing long-term mechanical ventilation

OBJECTIVE

The cuff-leak test has been proposed as a simple tool to clinically predict stridor or respiratory distress secondary to laryngeal edema following extubation. However, the true incidence of laryngeal edema in patients on long-term mechanical ventilation is uncertain. The relationship between upper airway obstruction (detected by video bronchoscopy) and the cuff-leak test value for patients with prolonged translaryngeal intubation during percutaneous dilatational tracheostomy (PDT) was investigated.

DESIGN

Prospective, clinical investigation.

SETTING

Intensive care unit of a university hospital.

PATIENTS

Ninety-five patients with prolonged translaryngeal intubation requiring PDT were enrolled during a 12-month period.

INTERVENTIONS

Cuff-leak test, PDT, video bronchoscopy.

MEASUREMENTS AND MAIN RESULTS

The average duration of translaryngeal intubation was 28.1 +/- 17.6 days. The incidence of severe laryngeal edema was 36.8% (35/95). We chose 140 mL as the threshold cuff-leak volume below which edema is indicated. The rate of cuff-leak test positivity was 38.9% (37/95). The sensitivity and the specificity of the test were 88.6% and 90.0%, respectively. The positive and negative predictive values were 83.8% and 93.1%, respectively. Patients who developed severe laryngeal edema had a smaller leak volume than those who did not, expressed in absolute values (53.9 +/- 56.2 vs. 287.9 +/- 120.0 mL; p < .001) or in relative values (10.1 +/- 10.2 vs. 55.3 +/- 22.7%, p < .001). The occurrence of severe laryngeal edema was not associated with age, gender, body weight, respiratory failure due to pneumonia, duration of translaryngeal intubation, endotracheal tube diameter, Acute Physiology and Chronic Health Evaluation II score, or history of self-extubation.

CONCLUSIONS

A reduced cuff-leak volume measured before PDT may signal the presence of severe laryngeal edema in patients on long-term mechanical ventilation.

An evaluation of McCoy balloon laryngoscopy in patients with moderate-to-major endotracheal intubation difficulty

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.