Hemodynamics and tissue oxygenation effects after increased in positive end-expiratory pressure in coronary artery bypass surgery

Abstract

BackgroundCardiac surgery is widely used in the treatment of cardiovascular diseases. However, several complications can be observed during the postoperative period. Positive end expiratory pressure (PEEP) improves gas exchange, but it might be related to decreased cardiac output and possible impairment of tissue oxygenation. The aim of this study was to investigate the hemodynamic effects and oxygen saturation of central venous blood (ScvO2) after increasing PEEP in hypoxemic patients after coronary artery bypass (CAB) surgery.MethodsSeventy post-cardiac surgery patients (CAB), 61 ± 7 years, without ventricular dysfunction (left ventricular ejection fraction 57 ± 2%), with hypoxemia (PaO2/FiO2 ratio <200) were enrolled. Heart rate, mean arterial pressure, arterial and venous blood samples were measured at intensive care unit and PEEP was increased to 12 cmH2O for 30 min.ResultsAs expected, PEEP12 improved arterial oxygenation and PaO2/FiO2 ratio (p < 0.0001). Reduction in ScvO2 was observed between PEEP5 (63 ± 2%) and PEEP12 (57 ± 1%; p = 0.01) with higher values of blood lactate in PEEP12 (p < 0.01). No hemodynamic effects (heart rate, mean arterial pressure, SpO2; p > 0.05) were related.ConclusionIncreased PEEP after cardiac surgery decreased ScvO2 and increased blood lactate, even with higher O2 delivery. PEEP did not interfere in hemodynamics status in CAB patients, suggesting that peripheral parameters must be controlled and measured during procedures involving increased PEEP in post-cardiac surgery patients in the intensive care unit.

Impact of Lung Expansion Therapy Using Positive End-Expiratory Pressure in Mechanically Ventilated Patients Submitted to Coronary Artery Bypass Grafting

“…A concern regarding LET in this patient profile is hemodynamic instability with the need to increase the flow rate of vasoactive drugs. Méndez et al [15] did not verify hemodynamic changes when they compared patients after heart surgery receiving PEEP of 5 or 12 cmH 2 O. This corroborates with the results of the present study and ratifies the safety of the pre-extubation technique.…”

Use of positive end‐expiratory pressure (20 cmH2O) for 60 s during elective heart surgery: A randomized clinical trial

“…No significant differences between groups were found regarding the oxygenation index, but a reduction was found at all assessment times. In contrast, previous studies reported an improvement in the oxygenation index after alveolar recruitment therapy in the immediate postoperative period when the maneuver was performed with PEEP at 10 cmH 2 O (Borges et al., 2013; Dongelmans et al., 2012), 12 cmH 2 O (Méndez et al., 2017), 25 cmH 2 O (Oliveira et al., 2018), 20 cmH 2 O and 40 cmH 2 O (Celebi et al., 2007) as well as with different maneuver times, such as 30 s, 120 s (Celebi et al., 2007) and 30 min (Méndez et al., 2017). In a meta‐analysis involving a total of 1162 patients, those who received some type of intervention, such as CPAP or low ventilation, during ECC had a significant increase in the oxygenation index compared with those who did not receive any type of intervention (Chi et al., 2017).…”

“…The hemodynamic variables remained stable between the pre‐maneuver and post‐maneuver assessments as well as upon arrival to the ICU and no adverse events associated with the maneuver were observed. The alveolar recruitment maneuver in the postoperative period also maintains stable hemodynamic conditions with PEEP at 20 cmH 2 O in comparison to the maneuver with CPAP at 40 cmH 2 O (Celebi et al., 2007) and PEEP at 12 cmH 2 O for 30 min (Méndez et al., 2017).…”

Impact of Non-Invasive Ventilation Immediately After Extubation on Clinical and Functional Outcomes in Patients Submitted to Coronary Artery Bypass Grafting: Clinical Trial

“…Noninvasive ventilation (NIV) can be used right after extubation in order to minimize pulmonary dysfunction, reduce the length of stay in the intensive care unit (ICU) and represent an improvement in the functional capacity of these patients 8,9,10,11 . According to the mechanical ventilation (MV) guideline, NIV should be performed immediately after extubation, however in some services it appears on the first postoperative day as the institution's protocol 12 .…”