Study investigates difficulty swallowing in critically ill COVID-19 patients

An analysis was conducted in order to determine the swallowing problems of COVID-19 patients who had tracheostomy or mechanical ventilation. These patients had a higher incidence of swelling disorders, but they also recovered quickly and completely.

COVID-19 patients who are severely ill often require ventilation support to breathe. Sometimes ventilation is provided using invasive methods, which if required for a long time will need to be done by making an opening on the front of the neck so that a tube can be inserted into the windpipe, a process called a tracheostomy.

However, prolonged mechanical ventilation and tracheostomy can lead to dysfunction of the pharyngeal muscles causing difficulty swallowing (dysphagia), and swelling disorders. These are associated with other complications, leading to increased intensive care, prolonged hospital stay, and even death.

There is often conflicting evidence regarding the effects of mechanical ventilation and dysphagia. It has been reported that prolonged mechanical ventilation can lead to dysphagia, but other studies suggest more research is necessary to prove there is a link.

Researchers from Clinica Luganese Moncucco and Bellinzona Regional Hospital in Switzerland investigated the prevalence of swelling disorders in severely ill COVID-19 patients and reported their results in a paper posted to the medRxiv* preprint server.

Study: Dysphagic disorder in a cohort of COVID-19 patients: evaluation and evolution. Image Credit: Terelyuk / Shutterstock

Evaluating swallowing disorders

The researchers conducted a retrospective study of hospitalized patients admitted between March and April 2020. The patients were evaluated by speech and language therapists using the Gugging Swallowing Screen (GUSS). The test has a scoring system that categorizes swallowing disorders based on severity, with scores ranging from 0 for severe dysphagia to 20 for no dysphagia.

The assessment was performed once every week for four weeks, both in the intensive care unit and when the patients were transferred out. The team also considered demographics and other pre-existing illnesses like diabetes, hypertension, and chronic obstructive pulmonary disorder.

Of the 31 patients evaluated in the study, 25 underwent invasive mechanical ventilation and 19 underwent tracheostomy. Patients received mechanical ventilation for a median 11 days.

The team found no correlation between the GUSS scores and ventilation duration, tracheostomy, and length of stay in the intensive care unit in the first assessment conducted on day 0. Similarly, there was no correlation between the scores and demographics or other underlying conditions. The mean GUSS score was 15, with just under half the patients having no dysphagia and 19% having severe dysphagia.

A week after the first assessment, the GUSS scores of all the patients improved. About 6% had severe dysphagia and about 74% had no dysphagia.

As assessment continued for the next three weeks, the prevalence of severe dysphagia reduced to 0% and dysphagia decreased as the weeks passed, with almost 97% having no dysphagia after 28 days. By day 16, 90% of the patients had completely recovered from swallowing disorders. However, after hospital discharge, seven patients still had mild dysphagia.

Fast recovery

The results show that about half the patients had swallowing disorders at the first evaluation. In patients undergoing ventilation for more than 10 days, the prevalence of dysphagia was higher, about 95%. This suggests there is a high occurrence of dysphagia in COVID-19 patients even at an early stage. This could be because of the intense inflammatory response to the virus leading to general muscle impairment, including the throat muscles.

This is also supported by the correlation between disease severity and degree of dysphagia assessed the first time. Patient age was the only factor that acted as a predictor for a faster and higher loss of muscle activity.

Although the occurrence of dysphagia was high during hospital admission, recovery was also fast with speech and language therapy, with all severe cases improving after 12 days. This suggests speech and language therapy may help COVID-19 patients, improving recovery from any swallowing disorders. However, since this study was only a single-center study, more studies will be needed to understand swallowing disorders and their management in COVID-19 patients.

*Important Notice

medRxiv publishes preliminary scientific reports that are not peer-reviewed and, therefore, should not be regarded as conclusive, guide clinical practice/health-related behavior, or treated as established information.

Written by

Lakshmi Supriya

Lakshmi Supriya got her BSc in Industrial Chemistry from IIT Kharagpur (India) and a Ph.D. in Polymer Science and Engineering from Virginia Tech (USA).