Alveolar recruitment maneuver (ARM) using high airway pressures has been shown to re-expand atelectasis and to improve gas exchanges after general anesthesia; however, ARM may lead to lung stretching-induced inflammatory response. The objective of this study was to evaluate plasma cytokine behavior after an ARM in healthy volunteers.
After obtaining ethical committee approval and informed consent, a basal blood sample was collected in 10 healthy volunteers. Continuous positive airway pressure (CPAP) was noninvasively applied (BiPAP Vision®; Respironics, USA) using a total face mask. CPAP was increased by 3 cmH2O from 5 to 20 cmH2O every five breaths. At CPAP of 20 cmH2O, an inspiratory pressure of 20 cmH2O above CPAP was implemented during 10 breaths. After that, CPAP was stepwise decreased in an inverse fashion. Pulse oximetry, arterial pressure and heart rate were measured before and after ARM. Additional blood samples were drawn at 30 minutes, 2 and 12 hours. TNFα, IL-1β, IL-6, IL-8, IL-10 and IL-12 were measured by the flow cytometry technique (Cytometric Bead Array BD™ Kit). The highest cytokine value at 30 minutes or 2 hours after ARM was considered the peak value measurement. Data were analyzed using a paired t test and one-way RM ANOVA. P < 0.05 was significant.
Four men and six women with a mean age of 26 ± 1 years and mean BMI of 23.8 ± 3.6 kg/m2 were studied. No changes were observed in heart rate or MAP after ARM, while pulse oximetry increased from 97.2 ± 0.8% to 98.4 ± 0.7% (P = 0.009). As shown in Figure 1, ARM induced a significant increase in the peak plasma level concentration of all cytokines that returned to basal levels within 12 hours. No adverse effects were observed during and after ARM.
Despite beneficial effects in reversing atelectasis, ARM-induced lung stretching was associated with an inflammatory response in healthy volunteers.