Mark Bennett

Oxygen delivery during cardiopulmonary bypass (and renal outcome) using two systems of extracorporeal circulation: a retrospective review.

OBJECTIVES To investigate the combined influence of blood flow and haemodilution with either a miniaturized (Mini-CPB) or a conventional cardiopulmonary bypass (C-CPB) circuit on average oxygen delivery during bypass. The influence of this on clinical outcome, particularly renal dysfunction after routine coronary artery bypass surgery (CABG), was measured. METHODS Retrospective analysis in two groups of 160 patients based on the surgeons preference for bypass circuit. We compared consecutive patients undergoing isolated CABG surgery by two surgeons using Mini-CPB with a matched cohort of patients, from the same period, undergoing isolated CABG surgery by four other surgeons using a C-CPB. No trial-related intervention occurred. Data on bypass circuit parameters and clinical outcomes were acquired from routinely collected data sources. RESULTS Average cardiopulmonary bypass pump flow was significantly lower with Mini-CPB compared with C-CPB. Mini-CPB resulted in significantly less haemodilution. The resultant calculated average oxygen delivery provided by the two systems was the same. Percentage change in plasma creatinine was significantly and inversely related to the oxygen delivery during CPB. There was no difference in percentage change in plasma creatinine between groups. The risk of having Acute Kidney Injury Network (AKIN) score ≥ 1 increased 1% for every 1 ml min(-1) m(-2) decrease in oxygen delivery (P = 0.0001, OR 0.990, 95% CI 0.984-0.995). CONCLUSIONS Despite aiming for the same target pump flow, periodic limitations of venous return to the pump resulted in a significant reduction in average flow delivered to the patient by Mini-CPB. Less haemodilution compensated for this reduction, so that the average oxygen delivery was the same. The association between oxygen delivery and postoperative change in plasma creatinine was evident in both groups. Further work to understand whether there is a particular cohort of patients who benefit (or are put at risk) by one method of CPB vs the other is warranted.

Stented esophageal transfixion injury.

Esophageal perforation is a rare, but life-threatening condition with a mortality rate ranging between 10% and 40%. It can happen at the level of the cervical, intrathoracic, or intra-abdominal segment. It usually occurs as a result of iatrogenic injury after endoscopic procedures or as a spontaneous rupture. It is seen less frequently in trauma after gunshot or stab wounds. Stenting of the esophagus after iatrogenic perforation is well documented in the literature, but yet it is to be published for management of penetrating injury. We report a case of esophageal perforation with a wooden fence post treated successfully with a covered esophageal stent.

Minimal access aortic valve replacement using minimal extracorporeal circuit

A minimal extracorporeal circuit has been shown to decrease the transfusion rate, cardiac and neurological damage in coronary surgery. We describe in detail a technique for minimal-access aortic valve replacement using a minimal extracorporeal circuit, and provide surgical and perfusion tips to maintain antegrade perfusion and a clear surgical field.