Ahmed Elminshawy

A prospective randomized study to evaluate splanchnic hypoxia during beating-heart and conventional coronary revascularization

OBJECTIVE Cardiopulmonary bypass (CPB) is associated with gut mucosal hypoxia, which may contribute to gastrointestinal complications. We examined gastric mucosal oxygenation together with whole-body oxygen flux in low-risk patients undergoing coronary artery bypass grafting (CABG) with and without CPB. METHODS Fifty-four patients undergoing primary CABG by the same surgeon were randomized into either on-pump (ONCAB, n=27) or off-pump (OPCAB, n=27) groups. The ONCAB group underwent mild hypothermic (35 degrees C) pulsatile CPB with arterial line filtration. Each patient underwent perioperative monitoring with continuous tonometry and cardiac output devices. Gastric intramucosal pH (pHi), gastric-arterial carbon dioxide partial pressure difference (CO(2) gap), whole-body oxygen delivery (DO(2)) and consumption (VO(2)) and whole-body oxygen extraction fraction were measured at sequential time-points intraoperatively and up to 6 h postoperatively. Anaesthetic management was standardized. RESULTS Both groups had similar demographic makeup and extent of revascularization (ONCAB 2.6+/-0.9 grafts versus OPCAB 2.5+/-0.8 grafts; P=0.55). The ONCAB group had a mean (+/-SD) CPB time of 62+/-25 min and aortic cross-clamp time of 32+/-11 min. In both groups there was a similar and progressive drop in pHi intraoperatively. Postoperatively, there was a gradual separation between the groups with ONCAB patients showing no further decline in pHi, while further deterioration was observed in the OPCAB group up to 6 h postoperatively. There was a significant difference between the groups over time (P=0.03). There was a corresponding progressive rise in CO(2) gap perioperatively in both groups, with ONCAB patients demonstrating superior preservation of gastric mucosal oxygenation in the early postoperative period. Global oxygen utilization measurements showed superior DO(2) and VO(2) in the OPCAB group throughout the study. CONCLUSIONS Despite superior global oxygen flux associated with beating-heart revascularization, gastric mucosal hypoxia occurred to similar extents in both groups with worsening trends for the OPCAB patients postoperatively. The splanchnic pathophysiology during beating-heart revascularization should be further explored.

Magnesium Sulfate for Prophylaxis against Postoperative Atrial Fibrillation after Isolated Cardiac Valve Replacement Surgery in Adult Patients with Rheumatic Heart Disease: A Randomized Controlled Trial

Objectives: To evaluate the role of prophylactic magnesium sulfate administration in preventing postoperative atrial fibrillation (POAF), attenuating the inflammatory response and promoting myocardial protection after isolated cardiac valve replacement surgery in adult patients with rheumatic heart disease. Design: Prospective randomized, double-blind placebo-controlled trial. Methods: Sixty-four adult patients undergoing isolated cardiac valve replacement surgery were divided into two equal groups (32 patients in each). Patients in magnesium group (group M) received 2.5 gm of magnesium sulfate (dissolved in 100 mL of isotonic saline and infused over 2 h), twelve h preoperatively, within the first hour of ICU arrival, and on the 2nd and 3rd postoperative days (group M). Patients in the control group (group C) received a placebo of isotonic saline at the same time periods. Results: Prophylactic magnesium sulfate significantly decreased the incidence of POAF compared to the placebo group (P=0.005). White blood cell (WBC) count showed no significant difference between the two groups. C-reactive protein (CRP) level showed significant reduction during the 3rd, 4th, and 5th postoperative days in group M compared to group C (P=0.001, 0.001 & 0.012 respectively). Serum level of interleukin-6 (IL-6) showed a significant reduction on the 5th postoperative day in group M compared to group C (P=0.001). Both groups showed no significant differences in serum levels of troponin I during the study. Conclusion: Prophylactic use of magnesium sulfate in patients with rheumatic heart disease undergoing isolated cardiac valve replacement surgery can decrease the incidence of POAF. It may play a role in attenuating the inflammatory process associated with the use of cardiopulmonary bypass (CPB).

Traditional predictors of in-hospital mortality after coronary artery bypass grafting: Current status

The most serious early adverse events after coronary artery bypass grafting (CABG) include in-hospital mortality, low cardiac output, perioperative myocardial infarction, renal dysfunction, stroke, atrial fibrillation and sternal wound infection. Prediction of outcome after CABG has a considerable importance which constitutes guidance for proper perioperative care and improved postoperative outcome. Advances in anesthesia and surgical techniques play a role in enrollment of patients with higher risk for CABG which indicates periodic updating of the traditional predictors of outcome. This review tries to highlight the current status of the important preoperative predictors of early mortality and morbidity after CABG. Correspondence to: Yasser Ali Kamal, Department of Cardiothoracic Surgery, Minia Cardiothoracic University Hospital, El-Minya El-Jadeda, 61768, Minia, Egypt, Tel: 002-01123234736; Fax: 20-086 2342501; E-mail: yaser_ ali_kamal@yahoo.com