ARDS in Obese Patients: Specificities and Management

Abstract

This article is one of ten reviews selected from the Annual Update in Intensive Care and Emergency Medicine 2019. Other selected articles can be found online at https://www.biomedcentral.com/collections/annualupdate2019 . Further information about the Annual Update in Intensive Care and Emergency Medicine is available from http://www.springer.com/series/8901 .

Fig. 1

Pressures of the respiratory system. The respiratory system includes the lung and the chest wall, and the airway pressure is related to both transpulmonary pressure (lung assessment, =alveolar pressure − pleural pressure) and transthoracic pressure (chest and abdomen assessment, =pleural pressure − atmospheric pressure), which differ in the obese patient compared to the non-obese patient. The relative portion of pressure due to transthoracic pressure is higher in the obese patient than in the non-obese patient (elevated pleural pressure, which can be estimated by esophageal pressure). The plateau pressure represents the pressure used to distend the chest wall plus lungs. In obese patients, elevated plateau pressure may be related to an elevated transthoracic pressure, rather than an increase in transpulmonary pressure with accompanying lung overdistension. Usual driving pressure, i.e., transthoraco-pulmonary driving pressure (plateau pressure − positive end-expiratory pressure [PEEP]), may not be appropriate to assess the severity of obese patients with acute respiratory distress syndrome (ARDS). To differentiate the chest wall pressure from the lung pressure, assessing transpulmonary pressure (plateau pressure – PEEP – (inspiratory esophageal pressure − expiratory esophageal pressure)) using esophageal pressure may be appropriate in obese ARDS patients. Insp inspiratory, exp expiratory, esoph esophageal

Fig. 2

Prone positioning of obese patients. Step 1: The patient is lying down, under deep sedation and analgesia. One operator is at the head of the patient to secure the airway access, three operators are on the right, two on the left, and one is mobile. Step 2: The monitor is checked. The patient is then turned on the left side first. Step 3: The patient is then moved to the other side of the bed. Step 4: The patient is turned. Step 5: Upper chest and pelvic supports are placed to avoid abdominal compression. Step 6: Finally, compression points are checked regularly, and the head is turned every 2 h. Bed is positioned in a reverse Trendelenburg position