Role of proning and positive end-expiratory pressure in COVID-19

Table 4 Different views of Gattinoni et al[12] and Tobin et al[17]

Gattinoni et al[12]	Tobin et al[17]
Silent hypoxemia is caused by vasoplegia which increases the respiratory drive and increases the tidal volume, causing negative intrathoracic pressure. Dyspnea is not endorsed in the setting of near-normal respiratory compliance	Silent hypoxemia is caused by underlying physiologic mechanism such as fever causing right shift of oxygen dissociation curve, unreliability of pulse oximeter at SaO2 < 80% and decreased chemoreceptor response to PaO2 < 60 mmHg with normocapnia
Increased tidal volume causing progressive increase in negative intrathoracic pressure results in P-SILI	P-SILI needs further research and increase in tidal volume is not associated with requiring intubation, whereas, underlying critical condition leads to intubation
Esophageal manometric measurement of work of breathing is crucial to determine the inspiratory efforts of the patient. Esophageal pressure > 15 is associated with increased risk of lung injury and patient should be intubated as early as possible	No data available to support the arbitrary measurement of esophageal pressure as an indication of intubation. Also, insertion of esophageal balloon in dyspneic COVID-19 patients increases the risk for intubation
Early intubation is advised along with esophageal manometric measurement of work of breathing	Less liberal use of intubation and mechanical ventilation. Should be used when hypoxia is accompanied with increased work of breathing and severe respiratory distress
Spontaneous breathing trials should be implemented only at the end of the weaning process as strong spontaneous efforts raise oxygen demand, edema and P-SILI	Weaning and spontaneous breathing trial should be initiated as early as 24 h after initial intubation

P-SILI: Patient-self-induced lung injury; COVID-19: Coronavirus disease 2019.