Brian Glenville

Plasma Antioxidants: Evidence for a Protective Role against Reactive Oxygen Species following Cardiac Surgery

Total plasma antioxidant status (TPAS), lipid peroxide concentration (LPX) and cardiac troponin T (cTnT) were measured in 24 patients undergoing coronary artery bypass grafting (CABG) with cardiopulmonary bypass (CPB). Samples were obtained preoperatively and at 1.5 h, 6 h, 24 h and 72 h after CPB. The absolute TPAS values were significantly lower at 1.5 h, 6 h, 24 h and 72 h after CPB than were preoperative values (P < 0.05). The LPX concentration was significantly elevated at 1.5 h after CPB (P < 0.05). Cardiac troponin T concentrations were significantly elevated at all time points postoperatively (P < 0.05). Preoperative TPAS values were significantly correlated with the magnitude of fall in TPAS at 1.5 h (P < 0.05). The greater the fall in TPAS between 0 and 1.5 h, the less LPX was formed between 0 and 1.5 h. The LPX at 1.5 h displayed a significant correlation with cTnT release from myocardial myocytes (P < 0.05). These data provide evidence for the first time that the consumption of antioxidants during CABG surgery with CPB protects against the production of reactive oxygen species and subsequent myocyte necrosis. Furthermore, the availability of protective antioxidants is dependent upon preoperative TPAS.

CORONARY ARTERY SURGERY WITH PATIENT'S LUNGS AS OXYGENATOR

The use of the patients own lungs as oxygenator was assessed during coronary artery bypass grafting in 20 patients. This technique maintained the circulation and provides excellent oxygenation, and the lungs did not intrude on the operative field. Blood damage as assessed by platelet function and lung sequestration was less than that reported with other forms of bypass. No microbubbles were produced, since there was no artificial blood/air interface. Complement activation, as assessed by amount of white-cell sequestration in the lungs, was also lower than that reported in other forms of bypass. There were no major complications attributable to the technique. Apart from being substantially cheaper than conventional cardiopulmonary bypass, the use of the patients lungs as oxygenator offers the potential advantage of reduced trauma to the blood and merits further consideration.

Review article : Cardiac surgery using the patient's lungs as the oxygenator

It is now over 35 years since the first cardiac operations were performed with the benefit of cardiopulmonary bypass. Since that time, great efforts have gone into methods of improving the quality of that bypass. This review details the history of the double reservoir technique which, instead of an external oxygenator, utilises the patient’s own lungs as the oxygenator; it also describes some of the

CABG 15-Years after Left Pneumonectomy: Feasibility of Off-Pump Approach

We report the case of a 70-year-old man who underwent off-pump coronary artery bypass grafting 15-years after left pneumonectomy. He had significant two-vessel coronary artery disease. Comorbidities included poor ventricular function and impaired respiratory function. Operative risks in this clinical setting is increased. Our patient underwent off-pump CABG x 2. Thoracic epidural analgesia was also used to facilitate post-operative recovery. The patient was extubated an hour after the end of the procedure. The role of off-pump surgery in this high-risk population and the use of stabilizing devices in these extreme anatomical situations is discussed.

A new method of grafting the circumflex through lateral MIDCAB with the use of the radial loop technique

We report a technique that allows total arterial revascularization of the circumflex territory without cardiopulmonary bypass through limited thoracotomy with the radial as a composite graft. The technique includes anastomosis of the distal end of the radial artery to its more proximal part after the division of the conduit from the brachial artery. In this way we create an adjustable loop that can be divided and used as bifurcated conduit in two coronary targets according to the needs of revascularization.

Pulmonary artery reconstruction for tuberculosis

A 35-year-old woman underwent reconstruction of her right pulmonary artery for treatment of acquired right pulmonary artery stenosis. The stenosis was secondary to tuberculosis causing both an extrinsic and an intrinsic obstructive component. After her reconstruction, the patient made an uneventful recovery, and perfusion to the right lung was subsequently restored.

A techniaue of anaesthesia and surgery for the implantation of ventricular assist devices in sheep

A technique of anaesthesia and surgery used in sheep, during insertion of ventricular asssist devices is described. Some animals also underwent double- reservoir cardiopulmonary bypass. Reference is made to previous reports of such techniques in sheep.

Use of an intraaortic balloon pump as a pneumatic ventricular assist device controller

Using a circulatory analogue, we investigated sequentially the performance of a dedicated ventricular assist device driver and an intraaortic balloon pump when driving a pneumatic ventricular assist device. Each drive device was compared under identical pumping conditions at rates of 40 to 120 cycles/min against two resistances. Our preliminary study showed that a modified intraaortic balloon pump could drive a pneumatic ventricular assist device as effectively as its dedicated driver. The necessary modifications to and possible further development of the intraaortic balloon in this role are discussed.

The prevention of trapped air within ventricular assist devices during connection to the circulation

One of the major concerns when implanting a ventricular assist device (VAD) is the total exclusion of air which is potentially dangerous to the patient. We found in our early experience with VADs that the complete removal of air during connection proved difficult. We have developed a simple and effective method of priming the VADs and removing air. The method relies upon the relative solubilities in blood of C02 and air.