Ventilation during cardiopulmonary bypass did not attenuate inflammatory response or affect postoperative outcomes : cardiovascular topic

Abstract

IntroductionCardiopulmonary bypass causes a series of inflammatory events that have adverse effects on the outcome. The release of cytokines, including interleukins, plays a key role in the pathophysiology of the process. Simultaneously, cessation of ventilation and pulmonary blood flow contribute to ischaemia–reperfusion injury in the lungs when reperfusion is maintained. Collapse of the lungs during cardiopulmonary bypass leads to postoperative atelectasis, which correlates with the amount of intrapulmonary shunt. Atelectasis also causes post-perfusion lung injury. In this study, we aimed to document the effects of continued low-frequency ventilation on the inflammatory response following cardiopulmonary bypass and on outcomes, particularly pulmonary function.MethodsFifty-nine patients subjected to elective coronary bypass surgery were prospectively randomised to two groups, continuous ventilation (5 ml/kg tidal volume, 5/min frequency, zero end-expiratory pressure) and no ventilation, during cardiopulmonary bypass. Serum interleukins 6, 8 and 10 (as inflammatory markers), and serum lactate (as a marker for pulmonary injury) levels were studied, and alveolar–arterial oxygen gradient measurements were made after the induction of anaesthesia, and immediately, one and six hours after the discontinuation of cardiopulmonary bypass.ResultsThere were 29 patients in the non-ventilated and 30 in the continuously ventilated groups. The pre-operative demographics and intra-operative characteristics of the patients were comparable. The serum levels of interleukin 6 (IL-6) increased with time, and levels were higher in the non-ventilated group only immediately after discontinuation of cardiopulmonary bypass. IL-8 levels significantly increased only in the non-ventilated group, but the levels did not differ between the groups. Serum levels of IL-10 and lactate also increased with time, and levels of both were higher in the non-ventilated group only immediately after the discontinuation of cardiopulmonary bypass. Alveolar–arterial oxygen gradient measurements were higher in the non-ventilated group, except for six hours after the discontinuation of cardiopulmonary bypass. The intubation time, length of stay in intensive care unit and hospital, postoperative adverse events and mortality rates were not different between the groups.ConclusionDespite higher cytokine and lactate levels and alveolar–arterial oxygen gradients in specific time periods, an attenuation in the inflammatory response following cardiopulmonary bypass due to low-frequency, low-tidal volume ventilation could not be documented. Clinical parameters concerning pulmonary and other major system functions and occurrence of postoperative adverse events were not affected by continuous ventilation.

Quercetin protects against inflammation, MMP‑2 activation and apoptosis induction in rat model of cardiopulmonary resuscitation through modulating Bmi‑1 expression

“…Under strong pathological stimuli, cytokines are produced and cascade reactions are triggered. Reperfusion injury following cardiac arrest is closely associated with pro-inflammatory cytokines, including TNF-α, IL-1 and IL-6 (21). The current study demonstrated that treatment with quercetin significantly inhibited the activation of IL-6 and TNF-α release and suppressed ROS generation in CPR model rats.…”

“…Effective and timely CPR may restore the heart beat for the majority of patients (20). However, cerebral injury following resuscitation remains difficult issue for complete rehabilitation (21). Following successful CPR, the autonomic circulation recovery of the cerebral blood flow causes cerebral-reperfusion injury and may cause further aggravation of the prognosis of cerebral functions and mortality (22).…”

Low‐frequency ventilation during cardiopulmonary bypass for lung protection: A randomized controlled trial

“…The postbypass extravascular lung fluid was significantly smaller in the VB group compared to the NVB group and extubation time was significantly shorter, hence this study has shown the benefits of maintaining ventilation during CPB on post‐CPB oxygenation and included shorter mechanical ventilation . In contrast, a small study of fifty‐nine patients prospectively randomized to continuous ventilation and no ventilation, during CABG on CPB, showed there was no statistically significant difference in most of the inflammatory makers (IL‐6, IL8, IL‐10, and lactate) . A recent meta‐analysis for patients undergoing cardiac surgery and received ventilation during CPB included seventeen trials with 1162 patients, showed that ventilation during CPB significantly increased post‐CPB PaO 2 /FiO 2 ratio, but there was no sufficient evidence to show that ventilation during CPB could influence long‐term prognosis of these patients …”

Effects of Positive Airway Pressure and Mechanical Ventilation of the Lungs During Cardiopulmonary Bypass on Pulmonary Adverse Events After Cardiac Surgery: A Systematic Review and Meta-Analysis

“…18,19 Ultimately, 15 articles published between 1993 and 2016 involving 748 patients were selected for this systematic review. 10,11,13,18,[20][21][22][23][24][25][26][27][28][29][30][31] All these studies compared ventilation with or without PEEP, apnea with CPAP, and apnea without CPAP (control) as their primary research purpose.…”

“…9 Continuous ventilation with a low tidal volume during CPB appears to reduce extravascular lung water and certain proinflammatory and anti-inflammatory mediator levels. [10][11][12][13][14][15] Whether ventilation during CPB improves a patient's clinical outcomes and oxygenation status remains unclear.…”