Recruitment maneuver: does it promote bacterial translocation?

Area of Science:

• Critical care medicine
• Pulmonary physiology
• Infectious disease

Background:

• Recruitment maneuvers (RMs) use high airway pressures to open collapsed lung units.
• High pressures may cause lung injury and bacterial translocation.
• The risk of bacterial translocation during RMs needs further investigation.

Purpose of the Study:

• To investigate if recruitment maneuvers with high peak airway opening pressures (Pao) cause bacterial translocation from the alveoli into the systemic circulation.
• To compare bacterial translocation in rats subjected to low-pressure ventilation, high-pressure ventilation, and recruitment maneuvers.

Main Methods:

• A prospective, randomized animal study was conducted on 18 male Sprague Dawley rats.
• Rats were intratracheally inoculated with bacteria and randomized into three groups: low-pressure (14 cm H2O Pao), high-pressure (45 cm H2O Pao), and recruitment maneuver (sustained inflation of 45 cm H2O CPAP).
• Blood cultures and blood gas analysis were performed to assess for bacteremia and oxygenation over 2 hours.

Main Results:

• Bacteremia was detected in only 6 rats in the high-pressure group; blood cultures were negative in the low-pressure and recruitment maneuver groups.
• Oxygenation significantly deteriorated in the high-pressure group (417 to 79 mm Hg) and the low-pressure group (410 to 287 mm Hg).
• Oxygenation also decreased in the recruitment maneuver group (383 to 249 mm Hg), but this change was not statistically significant.

Conclusions:

• Intermittent recruitment maneuvers, as applied in this study, did not cause translocation of intratracheally inoculated bacteria.
• High peak airway pressures alone, without recruitment maneuvers, may lead to bacterial translocation.
• Recruitment maneuvers, when used with low-pressure ventilation, appear safe regarding bacterial translocation.