Faleh Al-Rashidi

Comparison of the effectiveness and safety of a new de-airing technique with a standardized carbon dioxide insufflation technique in open left heart surgery: A randomized clinical trial.

OBJECTIVE We have compared the effectiveness, time required for de-airing, and safety of a newly developed de-airing technique for open left heart surgery (Lund technique) with a standardized carbon dioxide insufflation technique. METHODS Twenty patients undergoing elective open aortic valve surgery were randomized prospectively to the Lund technique (Lund group, n = 10) or the carbon dioxide insufflation technique (carbon dioxide group, n = 10). Both groups were monitored intraoperatively during de-airing and for 10 minutes after weaning from cardiopulmonary bypass by transesophageal echocardiography and online transcranial Doppler for the severity and the number of gas emboli, respectively. The systemic arterial partial pressure of carbon dioxide and pH were also monitored in both groups before, during, and after cardiopulmonary bypass. RESULTS The severity of gas emboli observed on transesophageal echocardiography and the number of microembolic signals recorded by transcranial Doppler were significantly lower in the Lund group during the de-airing procedure (P = .00634) and in the first 10 minutes after weaning from cardiopulmonary bypass (P = .000377). Furthermore, the de-airing time was significantly shorter in the Lund group (9 vs 15 minutes, P = .001). The arterial pH during the cooling phase of cardiopulmonary bypass was significantly lower in the carbon dioxide group (P = .00351), corresponding to significantly higher arterial partial pressure of carbon dioxide (P = .005196) despite significantly higher gas flows (P = .0398) in the oxygenator throughout the entire period of cardiopulmonary bypass. CONCLUSIONS The Lund de-airing technique is safer, simpler, and more effective compared with the carbon dioxide insufflation technique. The technique is also more cost-effective because the de-airing time is shorter and no extra expenses are incurred.

A new de-airing technique that reduces systemic microemboli during open surgery: a prospective controlled study.

OBJECTIVE We have evaluated a new technique of cardiac de-airing that is aimed at a) minimizing air from entering into the pulmonary veins by opening both pleurae and allowing lungs to collapse and b) flushing out residual air from the lungs by staged cardiac filling and lung ventilation. These air emboli are usually trapped in the pulmonary veins and may lead to ventricular dysfunction, life-threatening arrhythmias, and transient or permanent neurologic deficits. METHODS Twenty patients undergoing elective true left open surgery were prospectively and alternately enrolled in the study to the conventional de-airing technique (pleural cavities unopened, dead space ventilation during cardiopulmonary bypass [control group]) and the new de-airing technique (pleural cavities open, ventilator disconnected during cardiopulmonary bypass, staged perfusion, and ventilation of lungs during de-airing [study group]). Transesophageal echocardiography and transcranial Doppler continually monitored the air emboli during the de-airing period and for 10 minutes after termination of the cardiopulmonary bypass. RESULTS The amount of air embolism as observed on echocardiography and the number of microembolic signals as recorded by transcranial Doppler were significantly less in the study group during the de-airing time (P < .001) and the first 10 minutes after termination of cardiopulmonary bypass (P < .001). Further, the de-airing time was significantly shorter in the study group (10 vs 17 minutes, P < .001). CONCLUSION The de-airing technique evaluated in this study is simple, reproducible, controlled, safe, and effective. Moreover, it is cost-effective because the de-airing time is short and no extra expenses are involved.

Risks Associated With the Transfusion of Various Blood Products in Aortic Valve Replacement.

BACKGROUND Patients undergoing cardiac operations often require transfusions of red blood cells, plasma, and platelets. From a statistical point of view, there is a significant collinearity between the components, but they differ in indications for use and composition. This study explores the relationship between the transfusion of different blood components and long-term mortality in patients undergoing aortic valve replacement alone or combined with revascularization. METHODS A retrospective single-center study was performed including 1,311 patients undergoing aortic valve replacement. Patients who received more than 7 units of red blood cells, those who died early (7 days), and emergency cases were excluded. Patients were monitored for up to 9.5 years. A broad selection of potential risk factors were analyzed using Cox proportional hazards regression, where transfusion of red blood cells, plasma, and platelets were forced to remain in the model. RESULTS The transfusion of red blood cells was not associated with decreased long-term survival (hazard ratio [HR], 1.01; p = 0.520) nor was the transfusion of platelets (HR, 0.946; p = 0.124); however, the transfusion of plasma was (HR, 1.041; p < 0.001). All HRs are per unit of blood product transfused. No increased risk was found for patients undergoing a combined procedure. CONCLUSIONS No significant risk for long-term mortality was associated with transfusion of red blood cells during the study period. However, the transfusion of plasma was associated with increased mortality.

A new technique to reduce residual air emboli in open left cardiac surgery.

Residual air emboli, as seen on intraoperative transesophageal echocardiographic (TEE) analysis after termination of cardiopulmonary bypass (CPB) for true open left cardiac surgery, might lead to ventricular dysfunction, life-threatening arrhythmias, and transient or permanent neurologic deficits. These residual air emboli can show on TEE analysis for as long as 28 minutes after the termination of CPB. We report here an original technique of cardiac deairing that is aimed at reducing residual air emboli by (1) minimizing air from entering into the pulmonary veins and (2) flushing out residual air from the lungs, even at low right cardiac output.

Pulmonary collapse alone provides effective de-airing in cardiac surgery: a prospective randomized study

Objectives: We previously described and showed that the method for cardiac de-airing involving: (1) bilateral, induced pulmonary collapse by opening both pleurae and disconnecting the ventilator before cardioplegic arrest and (2) gradual pulmonary perfusion and ventilation after cardioplegic arrest is superior to conventional de-airing methods, including carbon dioxide insufflation of the open mediastinum. This study investigated whether one or both components of this method are responsible for the effective de-airing of the heart. Methods: Twenty patients scheduled for open, left heart surgery were randomized to two de-airing techniques: (1) open pleurae, collapsed lungs and conventional pulmonary perfusion and ventilation; and (2) intact pleurae, expanded lungs and gradual pulmonary perfusion and ventilation. Results: The number of cerebral microemboli measured by transcranial Doppler sonography was lower in patients with open pleurae 9 (6-36) vs 65 (36-210), p=0.004. Residual intra-cardiac air grade I or higher as monitored by transesophageal echocardiography 4-6 minutes after weaning from cardiopulmonary bypass was seen in few patients with open pleurae 0 (0%) vs 7 (70%), p=0.002. Conclusions: Bilateral, induced pulmonary collapse alone is the key factor for quick and effective de-airing of the heart. Gradual pulmonary perfusion and ventilation, on the other hand, appears to be less important.

Comparison between transcranial Doppler and coulter counter for detection of lipid micro embolization from mediastinal shed blood reinfusion during cardiac surgery.

Introduction: Lipid micro embolization (LME) from re-transfused shed blood has been postulated to be a potential reason for short- and long-term cognitive dysfunction after cardiac surgery. The purpose of this investigation was to evaluate if transcranial Doppler (TCD) has the capacity to detect LME. Methods: Thirteen patients undergoing cardiopulmonary bypass surgery were investigated. Each patient’s cerebral circulation was monitored with transcranial Doppler during the first two minutes after re-transfusion of shed blood and blood was simultaneously sampled and characterised by a Coulter counter. Results: Strong correlation was found between embolic loads, as measured by transcranial Doppler and Coulter counter (r=0.79, P<0.005). Conclusions: This pilot study shows that non-invasive monitoring by transcranial Doppler could be a potential tool to monitor LME during cardiopulmonary bypass surgery.