The WHO declared COVID-19 a pandemic on March 11, 2019. This new disease has brought intensive care units (ICUs) and the consequences of prolonged admission into focus. Such consequences include dysphagia, defined as the inability to swallow liquid and/or solid elements due to a structural or functional impairment of one or more swallowing phases 1.
In recent years, there has been a considerable increase in the number of publications that discuss dysphagia associated with ICU admission. Although the number of publications is very important, their quality is questionable for several reasons: 1) the heterogeneity of the pathology presented by hospitalised patients (postsurgical patients, patients with neurological, septic pathology, etc.); 2) the changes made in recent years with respect to early mobilisation that entail a functional improvement; 3) the different diagnostic methods used; and 4) ignorance of the presence of previous dysphagia, among other issues 2–6. Knowing the real incidence of dysphagia associated with ICU admission presents a challenge; according to a systematic review, it can vary from 3–62% 7.
The pathophysiology of dysphagia in critically ill patients has been widely described 8. The six most important mechanisms are direct trauma to the orotracheal tubes and/or tracheostomy, ICU-acquired weakness 9, decreased laryngeal sensitivity, altered consciousness, the presence of gastroesophageal reflux and asynchrony between respiration and swallowing 10,11. Among the described risk factors for dysphagia, several are clearly identified, such as congestive heart failure, functional status prior to admission, increased hospital and ICU stay, hypercholesterolemia, prolonged surgical time and the performance of perioperative transoesophageal echocardiography 8. One factor associated with the development of dysphagia in the ICU is ICU-acquired weakness (ICUAW). The swallowing apparatus is muscular and, therefore, is affected in the same way as other muscles 10,12.
To these “classic” factors, others associated with SARS-CoV-2 pneumonia have been added. Treatment for SARS-CoV-2 13 includes corticosteroids, which produce myopathy as a side effect; hydroxychloroquine, which increases corticosteroid myopathy; deep sedation and relaxation for a prolonged period; additionally, orotracheal intubation causes physical damage, patients may need to be positioned in prone decubitus, and SARS-CoV-2 infection itself can cause neurological damage (stroke, encephalitis and Guillain-Barré, among other concerns). All of these factors favour the development of ICUAW and, therefore, the occurrence of dysphagia 14,15.
Critically ill patients with dysphagia have higher morbidity than those without dysphagia. Thus, they more frequently require reintubation with a greater probability of death, they frequently require surgical access to food, they have longer hospital stays and, frequently, they need to be discharged to rehabilitation centres 8.
The duration of ICU-related dysphagia varies depending on the cause, but in general, patients recover in a short period of time since dysphagia in these cases is closely related to ICUAW16,17.
Currently, for the diagnosis of dysphagia in critical patients, either of two “gold standard” tests should be used: Videofluoroscopic swallowing study (VFSS) 18 or fibreoptic endoscopic evaluation of swallowing (FEES) 19,20. In a VFSS, water with barium contrast is administered at different volumes and textures, and the moment of swallowing is visualised using continuous scanning. In comparison, for FEES, an endoscope is introduced through the nostrils to the glottic area, and swallowing is observed directly as the patient consumed water with different volumes and textures 21. Both explorations are relatively contraindicated in cases of SARS-CoV-2 infection since they generate aerosols, which favour contagion; thus, the published articles do not recommend their use, and such studies should be strictly limited to patients with a high risk of aspiration/malnutrition22.
Therefore, a bedside screening test is recommended. For this, complete personal protective equipment (PPE) must be worn with an FFP3 mask, and it is recommended to keep 2 metres away from the patient at the time of swallowing and to stay to the patient’s side to avoid the trajectory of the aerosols22. Two years before the pandemic, our centre validated the Modified Viscosity Volume Swallowing Test (mV-VST) 23, a bedside screening method that facilitates the diagnosis of dysphagia and was performed during the first wave of the pandemic prior to the start of the oral diet (Fig. 1).
The purpose of this study was to determine the incidence of dysphagia with the mV-VST and to identify the factors associated with its occurrence in patients with severe pneumonia due to COVID-19.