Postperfusion lung syndrome: physiopathology and therapeutic options

Effect of static lung expansion on pulmonary function following cardiopulmonary bypass in children

Objective

To observe the effect of the lung-protective ventilation strategy, static lung expansion, during cardiopulmonary bypass (CPB) on pulmonary function and tracheal intubation time following cardiac surgery in children.

Methods

A total of 48 child patients (aged 1-3) with ventricular septal defect (VSD) were enrolled, and all underwent CPB cardiac surgery for the first time. The patients were divided into two groups using the random number table method: the experimental group (Group A, n = 30) and the control group (Group B, n = 18). After terminating the mechanical ventilation during CPB, the adjustable pressure limiting valve of the anesthesia machine was adjusted in the experimental group to maintain the pressure of the breathing circuit at 5 cmH2O, such that both lungs remained in a static expansion state. In the control group, routine mechanical ventilation was terminated as usual.

Results

When static lung expansion with a continuous positive airway pressure of 5 cmH2O was employed in the VSD children during CPB, compared with termination of mechanical ventilation, the partial pressure of oxygen in the arterial blood increased, while the respiratory index decreased and the oxygenation index increased following the surgery.

Conclusion

In child patients undergoing VSD reparation under CPB, lung injury occurs following the procedure, and the pulmonary oxygenation function and pulmonary oxygen diffusion function decrease. When static lung expansion of 5 cmH2O is performed during CPB, the improvement in lung function is better than that of apnea without lung expansion pressure.

Case Report: Emergency CABG Following Failure of PTCA in a COVID-19 Patient

The coronavirus disease 2019 (COVID-19) pandemic outbreak, caused by severe acute respiratory syndrome coronavirus-2 (SARS-Cov-2) is affecting people worldwide representing a public health emergency. The effect of concomitant COVID-19 on patients who underwent cardiac surgery using cardiopulmonary bypass (CPB) is still undefined. Both SARS-Cov-2 infection and CPB can develop a cytokines storm and haemostatic disarrangements leading to acute respiratory distress syndrome (ARDS) and post-perfusion lung syndrome, respectively. SARS-Cov-2 infection may trigger and exacerbate post-inflammatory state after CPB resulting in higher risk of post-surgical adverse outcomes. International guidelines lack to provide standard management protocols for pre-operative COVID-19 patients requiring non-deferrable cardiac surgery intervention. We present a report of a successful coronary artery bypass grafting (CABG) emergency operation in a COVID-19 patient, who presented unstable angina and coronary artery dissection during cardiac catheterization and percutaneous transluminal coronary angioplasty (PTCA).

Effects of cardiopulmonary bypass on lung nuclear factor-kappa B activity, cytokine release, and pulmonary function in dogs

OBJECTIVES

To study the effect of cardiopulmonary bypass (CPB) on nuclear factor-kappa B (NF-κB) and cytokine expression and pulmonary function in dogs.

MATERIALS AND METHODS

Twelve male mongrel dogs were divided into a methylprednisolone group (group M) and a control group (group C). All animals underwent aortic and right atrial catheterization under general anesthesia. Changes in pulmonary function and hemodynamics were monitored and the injured site was histologically evaluated.

RESULTS

The activity of NF-κB and myeloperoxidase (MPO), levels of tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6, and IL-8, and the wet/dry (W/D) weight ratio were significantly higher after CPB than before CPB in both groups (P<0.01), with the lower values in group M than in group C, at different time points (P<0.01). Histological evaluation revealed neutrophilic infiltration and thickening of the alveolar interstitium in both groups; however, the degree of pathological changes was significantly lower in group M than in group C. The alveolar-arterial O2 tension difference (PA-aDO2) was significantly higher after CPB than before CBP (P<0.01), and lower in group M than in group C (P<0.01). The pulmonary compliance after removal of the aortic clamp obviously decreased in group C (P<0.05), with no significant change in group M.

CONCLUSION

CPB can significantly enhance the activation of NF-κB in lung tissues and increase the expression of inflammatory cytokines, thus inducing lung injury. Methylprednisolone can inhibit the NF-κB activation, thus inhibiting the release of cytokines and protecting the lung function.