The impact of off-pump surgery in end-organ function: practical end-points

A Comparison of Patients Undergoing On- vs. Off-Pump Coronary Artery Bypass Surgery Managed with a Fast-Track Protocol

The purpose of this study was to compare patients who underwent on- vs. off-pump coronary artery bypass surgery managed with a fast-track protocol. Between September 2012 and December 2018, n = 3505 coronary artery bypass surgeries were managed with a fast-track protocol in our specialized post-anesthesia care unit. Propensity score matching was applied and resulted in two equal groups of n = 926. There was no significant difference in ventilation time (on-pump 75 (55-120) min vs. off-pump 80 (55-120) min, p = 0.973). We found no statistically significant difference in primary fast-track failure in on-pump (8.2% (76)) vs. off-pump (6% (56)) groups (p = 0.702). The secondary fast-track failure rate was comparable (on-pump 12.9% (110) vs. off-pump 12.3% (107), p = 0.702). There were no significant differences between groups in regard to the post-anesthesia care unit, the intermediate care unit, and the hospital length of stay. Postoperative outcome and complications were also comparable, except for a statistically significant difference in PACU postoperative blood loss in on-pump (234 mL) vs. off-pump (323 mL, p < 0.0001) and red blood cell transfusion (11%) and (5%, p < 0.001), respectively. Our results suggest that on- and off-pump coronary artery bypass surgery in fast-track settings are comparable in terms of ventilation time, fast-track failure rate, and postoperative complications rate.

Pulmonary Perfusion and Ventilation during Cardiopulmonary Bypass Are Not Associated with Improved Postoperative Outcomes after Cardiac Surgery

OBJECTIVES

Clinical trials of either pulmonary perfusion or ventilation during cardiopulmonary bypass (CBP) are equivocal. We hypothesized that to achieve significant improvement in outcomes both interventions had to be concurrent.

DESIGN

Retrospective case-control study.

SETTINGS

Major academic tertiary referral medical center.

PARTICIPANTS

Two hundred seventy-four consecutive patients who underwent open heart surgery with CBP 2009-2013.

INTERVENTIONS

The outcomes of 86 patients who received pulmonary perfusion and ventilation during CBP were retrospectively compared to the control group of 188 patients.

MEASUREMENTS AND MAIN RESULTS

Respiratory complications rates were similar in both groups (33.7 vs. 33.5%), as were the rates of postoperative pneumonia (4.7 vs. 4.3%), pleural effusions (13.9 vs. 12.2%), and re-intubations (9.3 vs. 9.1%). Rates of adverse postoperative cardiac events including ventricular tachycardia (9.3 vs. 8.5%) and atrial fibrillation (33.7 vs. 28.2%) were equivalent in both groups. Incidence of sepsis (8.1 vs. 5.3%), postoperative stroke (2.3 vs. 2.1%), acute kidney injury (2.3 vs. 3.7%), and renal failure (5.8 vs. 3.7%) was likewise comparable. Despite similar transfusion requirements, coagulopathy (12.8 vs. 5.3%, p = 0.031) and the need for mediastinal re-exploration (17.4 vs. 9.6%, p = 0.0633) were observed more frequently in the pulmonary perfusion and ventilation group, but the difference did not reach the statistical significance. Intensive care unit (ICU) and hospital stays, and the ICU readmission rates (7.0 vs. 8.0%) were similar in both groups.

CONCLUSION

Simultaneous pulmonary perfusion and ventilation during CBP were not associated with improved clinical outcomes.

Bedside Assessment of the Microvascular Venous Compartment in Cardiac Surgery Patients With Valvular Diseases Undergoing Cardiopulmonary Bypass

OBJECTIVE

Blood volume reserve for venous return and the effects of cardiopulmonary bypass (CPB) on microvascular bed partitioning and blood flow were examined in patients with valvular diseases.

DESIGN

Prospective, consecutive, case-control study.

SETTING

Single university hospital.

PARTICIPANTS

The study comprised 20 adult cardiac surgery patients and 20 healthy volunteers.

INTERVENTIONS

Cardiovascular and microvascular variables were collected soon after the induction of anesthesia, after commencement of CPB, 20 minutes after separation from CPB, and in the intensive care unit.

MEASUREMENTS AND MAIN RESULTS

The unstressed and stressed volumes (Vu, Vs) and pressures therein (Pit, Ps) were measured in the brachioradial muscle with near-infrared spectroscopy, applying incremental venous occlusions. At the first time point, Vs and Pit showed lower and higher values, respectively, than those of control patients, but Vs increased with Vu during the study, whereas Pit remained unchanged. Fluid balance correlated with Pit (r = 0.83, p<0.001) and hemoglobin (r = 0.78, p = 0.004). A nonlinear regression was found between fluid balance and ΔVu (r = 0.90, p<0.001) [y = 1.85+37.43^(-0.01×x)]. The Vu/Pit and Vs/Ps ratios were lower than those of the control patients. Blood flow correlated to Vs/Ps (r = 0.75, p<0.001). The time constant was lower than reference (p = 0.005) and increased 10 times after CPB.

CONCLUSIONS

Cardiac surgery patients have a limited blood volume reserve for venous return due to a reduced microvascular bed capacitance. This study demonstrated that during CPB a positive fluid balance induced an extravascular pressure increase and further reduced blood volume reserve.

Circulating microRNAs indicate cardioprotection by sevoflurane inhalation in patients undergoing off-pump coronary artery bypass surgery

In patients undergoing off-pump coronary artery bypass surgery (OPCAB), it is important to attenuate myocardium injury during the surgery. The present study aimed to observe the cardioprotection induced by sevoflurane induction and maintenance compared with propofol intravenous anesthesia, and to detect its potential protection against acute myocardial injury with sensitive biomarkers. In total, 36 patients undergoing OPCAB were randomly assigned into two groups, receiving sevoflurane (n=18) or propofol (n=18) as the induction and maintenance anesthetic agent. The depth of anesthesia in the two groups was kept at a bispectral index value of 40-50. Physiological and hemodynamic parameters were recorded during the surgery. Cardiac troponin-I (cTnI), creatine kinase-MB (CK-MB), lactate dehydrogenase (LDH) and two microRNAs (miR-499 and miR-208b) were also measured during and subsequent to surgery. Nno statistically significant differences were observed in the physiological and hemodynamic parameters between the two groups prior to surgery. Following surgery, the cardiac output and stroke volume improved significantly in the sevoflurane group (P<0.05). In addition, patients in the sevoflurane group had lower miR-499 (P<0.05) and miR-208b (P<0.01) levels at 12 h after surgery when compared with the propofol group. However, no significant differences in cTnI, CK-MB and LDH levels were observed following surgery between the two groups. In conclusion, volatile induction and maintenance with sevoflurane resulted in some extent of cardiac function improvement in patients undergoing OPCAB. Cardioprotection by sevoflurane is suggested by reduced cardiac injury compared with propofol, and indicated by the sensitive biomarkers, circulating miR-499 and miR-208b.