Critical Care Medicine-Pulmonary Disorders>>>>>Respiratory Diagnostic Modalities and Monitoring
Question 13#

A 48-year-male patient with a BMI of 48 kg/m² is undergoing a spontaneous breathing trial in anticipation of extubation.

What is the best position to optimize his respiratory mechanics?

A. Supine position
B. Trendelenburg
C. Beach chair position
D. Reversed Trendelenburg

Correct Answer is D

Comment:

Correct Answer: D

Morbid obese patients have a marked reduction in functional residual capacity mainly due to a reduction in expiratory reserve volume. The diaphragm is displaced upward decreasing lung and chest wall compliance. In contrast to supine position, both beach chair and reversed Trendelenburg positions increase functional residual capacity as well as spontaneous tidal volume. However, there is a larger increase seen in reversed Trendelenburg position. This is potentially because the lower leg position exerts less upward pressure on the abdomen and diaphragm. Hence, in morbidly obese individuals, it is recommended to perform spontaneous breathing trial, extubation, and preoxygenation in reverse Trendelenburg position.

Reference:

1. Couture EJ, Provencher S, Somma J, Lellouche F, Marceau S, Bussières JS. Effect of position and positive pressure ventilation on functional residual capacity in morbidly obese patients: a randomized trial. Can J Anesth. 2018;65(5):522-528.