From the Journals

Postextubation laryngeal injury has lasting effects


 

FROM CRITICAL CARE MEDICINE

More than half of patients who undergo prolonged mechanical ventilation experience an acute laryngeal injury (ALgI), and the injury is associated with worse breathing and speaking at 10 weeks, according to a study published in Critical Care Medicine (2019 Dec;47[12]:1669-1706). The researchers, led by Alexander Gelbard, MD, of Vanderbilt Medical Center, Nashville, Tenn., found that higher body mass index, diabetes, and larger endotracheal tube (ETT) size were all associated with heightened risk.

The investigators assert that comparatively scarce data are available about how patients fare after receiving mechanical ventilation, and how adverse effects might interfere with recovery and return to daily activity. The larynx is rarely examined after extubation, and laryngeal injury may initially appear to be minor. Restricted glottic mobility therefore tends to be diagnosed after discharge, leaving critical care specialists unaware of the long-term impact.

The findings of the study should be a wake-up call for the development of guidelines for recognition and management of laryngeal injuries, according to John Robert Gowardman, MD, of Royal Brisbane (Australia) and Women’s Hospital, who wrote an accompanying editorial (Crit Care Med, 2019 Dec;47[12]:1802-04).

In addition, findings that ETT size, diabetes, and BMI represent risk factors for injury should help identify patients at risk, and the “practice of ‘putting in the biggest ETT just in case’ needs to be balanced against the dangers of an undersized ETT ... we should ask, ‘can my patient be safely managed with a smaller ETT?’ ” wrote Dr. Gowardman.

The researchers followed 100 consecutive adult patients who were examined with nasolaryngoscopy following an intubation of greater than 12 hours at Vanderbilt University Medical Center. They recorded baseline comorbidities and other factors. Fifty seven patients had an ALgI, defined as having glottic mucosal ulceration/granulation or subglottic granulation tissue/stenosis at the time of endoscopy. Nineteen patients had granulation tissue, 48 had posterior glottic ulceration, and 8 had subglottic mucosal ulceration.

Ten weeks after extubation, all patients were contacted by phone and asked to answer the Voice Handicap Index (VHI)-10 and the Clinical Chronic Obstructive Pulmonary Disease Questionnaire (CCQ). The questioner did not know the results of the patient’s endoscopy. Patients with ALgI were heavier on average (mean difference, 14 kg; BMI difference, 3.8 kg/m2), were more likely to have type 2 diabetes (46% versus 21%), and had more severe illness (median Charlson Comorbidity Index, 3.00 versus 2.00).

Sixty-seven patients completed the 10-week questionnaires, including 40 patients with ALgI and 27 without ALgI. Injury was associated with reports of worse breathing (median CCQ, 1.05 versus 0.20; P less than .001), as well as worse patient-reported voice outcomes (median VHI, 2 versus 0; P = .005).

ETT size appeared to be an important factor, according to multivariate analyses. Use of a 7.0 ETT was associated with lower frequency of injury than 7.5 (adjusted odds ratio, 0.04; P = .004) and 8.0 (OR, 0.03; P = .004). There was no significant difference between the 7.5 and 8.0 sizes.

The presence of type 2 diabetes altered the risk associated with BMI (P = .003 for interaction). Among patients who did not have type 2 diabetes, ALgI went up as a function of increasing BMI. Still, injury risk was higher in the presence of type 2 diabetes across all BMI ranges.

The Vanderbilt Institute for Clinical and Translational Research funded the study. Dr. Gowardman has no relevant disclosures.

SOURCE: Shinn JR et al. Crit Care Med;2019 Dec;47(12):1669-1706 .

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