The Nature of Recruitment and De-Recruitment and Its Implications for Management of ARDS

Abstract

abdominal pressure, plateau pressure, positive end-expiratory pressure, threshold opening pressure, ventilator-induced lung injury. COI Statement: Mr. Kallet has received honorarium from Nihon Kohden for lectures given on the topic of alveolar recruitment maneuvers. Neither of the other authors have a conflict of interest to declare. Literature Review (RHK) Manuscript Development and Review (RHK, MSL, GB), Supplementary Data Abstraction and Analysis (GB) Some data was presented in abstract form (GB) during Open Forum at the 64 th AARC International Respiratory Congress in Las Vegas NV. December 2018.

Emergency Department Management of Severe Hypoxemic Respiratory Failure in Adults With COVID-19

“…When atelectasis occurs on a large scale, it results in the functional closure of lung units, leading to derecruitment ( 37 ). Derecruitment produces a large shunt and is a common cause of hypoxemia.…”

“…Conversely, because derecruitment is a major driver of severe hypoxemia in COVID-19, clinicians should minimize further derecruitment by maintaining PEEP ( 37 ). By expert consensus, if a patient requires changing from one ventilator to another, such as when being placed on a travel ventilator, the end of the endotracheal tube should be clamped with a Kelly clamp to prevent release of pressure and minimize aerosolization.…”

“…Given that derecruitment is a major driver of hypoxemia, attempts to recruit compressed lung segments may be appropriate in refractory hypoxemia ( 37 , 96 ). With the heterogeneity of ARDS, patients vary in their recruitablity, and a similar variation is seen with patients with COVID-19 ( 19 , 20 , 22 , 31 ).…”

“…The risks of performing a recruitment maneuver are threefold. Should a patient have severely stiff lungs, even gentle and sustained pressures can lead to pneumothorax, pneumomediastinum, or other barotraumas ( 37 , 97 , 98 ). Increased intrathoracic pressure from a recruitment maneuver can lead to decrease preload in a patient who is hypovolemic or an increase in afterload for the right ventricle, either of which may result in hypotension.…”

“…There have been appropriate concerns regarding the safety of recruitment maneuvers in terms of hemodynamics or worsening lung injury. However, it seems that the major deleterious effects arise from the rapid rise in pressure, as opposed to a more gentle, sustained pressure ( 37 , 99 ). A 2017 study found no improvement in patients treated with recruitment maneuvers and a subsequent best PEEP trial ( 97 ).…”