Discussion
The present study investigated the association between enteral feeding and survival levels in COVID-19 patients admitted to the ICU. The group of patients who survived had lower smoking and incidences of chronic diseases compared with the group of patients who died during the experimental period. Our results indicated that the mortality was inversely associated with high volume and high protein formula, after adjustments for age and sex, underlying diseases, smoking, BMI, and APACHII.
Previous studies reported that there was a positive association between smoking and the mortality rate in CODIV-19 patients (15). As evident in this study and those reported in the past, critical COVID-19 patients may have a relatively high risk of sudden death due to the underlying comorbidities including cardiovascular disease, chronic obstructive pulmonary disease (COPD), chronic kidney disease (CKD), and obstructive sleep apnea-hypopnea syndrome (OSAHS). Also, the underlying comorbidities were reported to be associated with higher in-hospital mortality (16) and lower survival rates (17).
The present study suggested an inverse relationship between mortality with high-volume and high-protein formula use in COVID-19 patients. In line with this study, Martindale et al. recommend using a standard high-protein (≥20% protein) polymeric iso-osmotic enteral formula in the early acute phase of critical illness (18). Martindale et al reported that enteral nutrition (EN) should be initiated early after admission to the intensive care unit (ICU), while careful monitoring for gastrointestinal intolerance, hemodynamic instability, and metabolic derangements are essential (18, 19). In addition, a recent retrospective study has shown that early EN in paralyzed patients was associated with less hospital mortality, and there was no increase in ventilator-associated pneumonia (20). However, some studies reported contradictory results where no significant association between mortality and high protein formula was found (21). These results together strongly emphasize the importance of enteral feeding for survival levels in ICU patients with COVID-19. Hyperglycemia when occurring in a critical physiological state (22, 23) is likely to contribute to poor clinical outcomes (24). Insulin resistance and hyperglycemia result in muscle protein breakdown (25, 26). Hence, high-protein nutrition helps glucose control, reduces insulin requirements, improves muscle synthesis, and provides substrates needed at the sites of tissue injury in critically ill patients (27, 28). The positive effect of protein is also attributable to the maintenance of nitrogen balance and lean body mass (29) and its effect on the production of neurotransmitters, glutathione synthesis, and other compounds required during the acute infection phase (30).