Önol Bilkay

Effect of pulsatile flow during cardiopulmonary bypass on thyroid hormone metabolism

Changes in thyroid hormone levels during and after cardiopulmonary bypass (CPB) are well documented. However, little is known about the effects of pulsatile flow during CPB on thyroid hormone metabolism. To examine the effect of flow pattern, a prospective study was carried out using 30 patients undergoing coronary artery bypass grafting. Fifteen patients had pulsatile flow during CPB and 15, nonpulsatile flow. Serum samples were obtained preoperatively, during bypass, and at 2 and 24 hours postoperatively. Thyroid-stimulating hormone, thyroxine (T4), triiodothyronine (T3), free T4, and free T3 levels were measured by radioimmunoassay. All measured hormone levels except free T4 and thyroid-stimulating hormone decreased after the initiation of CPB. There were no differences in preoperative values between the two groups. However, levels of T3 and free T3 during and after CPB showed a significant difference between the two groups, with a smaller decrease in patients in whom pulsatile flow was used during bypass (p < 0.05). Thyroxine, and thyroid-stimulating hormone free T4 values showed no difference between the two groups at any sampling time. These data provide support for the use of pulsatile flow during CPB to establish a more physiologic state and maintain better thyroid hormone metabolism.

Effects of flow types in cardiopulmonary bypass on gastric intramucosal pH

The aim of this study was to determine the relationship between splanchnic perfusion and oxygen consumption, and flow types in cardiopulmonary bypass (CPB), by measuring gastric intramucosal pH. Twenty patients undergoing elective open-heart surgery were prospectively randomized to receive either pulsatile or nonpulsatile flow during CPB. Gastric intramucosal pH was measured using gastric tonometry. A flowmeter was used to measure the inferior caval vein flow. A catheter was inserted through the femoral vein to sample blood from the iliac vein. Systemic vascular resistance index, gastric intramucosal pH, inferior caval vein flow and arterial, inferior vena caval and iliac venous blood gases were recorded at different times. Gastric intramucosal pH decreased in all patients; only in the nonpulsatile group was this decrease statistically significant. After 45 min of CPB, the pH was 7.37 ± 0.03 compared with the prebypass value of 7.48 ± 0.04 (p = 0.00016). After weaning from CPB, the pH was 7.358 ± 0.02 compared with the prebypass value (p = 0.000037). At 2 h post-operatively the pH was 7.416 ± 0.025 (p = 0.02). Systemic vascular resistance index rose in all patients during bypass in both groups. These changes did not have any statistical significances and after weaning from bypass returned to prebypass levels. We conclude that nonpulsatile flow in CPB is associated with reduced gastric intramucosal pH and the measurement of intramucosal pH during open-heart surgery provides important information about splanchnic perfusion.

Parenchymal Stapling in Pulmonary Lobectomies: Is it Really Necessary?

Automatic stapling devices are widely used for pulmonary exeresis, particularly in wedge or segmental resections. Infrequently, these instruments are also employed in lobectomies for the division of incomplete fissures. A prospective randomized study was undertaken to determine the efficacy of staplers in performing a lobectomy. Among 102 lobectomy patients, 59 (44 men, 15 women) who had incomplete fissures were included in the study. A stapler was used in 38 patients for completion of the fissures, whereas sharp dissection and the classic suture closure technique were employed in the remaining 21 patients. Duration of air leakage postoperatively did not differ significantly (p > 0.05) but the operation time was found to be shorter in the stapled-lobectomy group (67.63 ± 13.7 min versus 85.71 ± 18.3 min; p < 0.001).

CLINICAL RESULTS OF RETROGRADE CEREBRAL PERFUSION IN TREATMENT OF AORTIC DISEASE

Between 1993 and 1998, 106 adults underwent ascending aorta or aortic arch operations using deep-hypothermic circulatory arrest and retrograde cerebral perfusion via the superior vena cava. Aortic lesions were acute type I dissection in 44 (41.5%), chronic type I dissection in 12 (11.3%), acute type II dissection in 6 (5.7%), chronic type II dissection in 9 (8.5%), ascending aorta or aortic arch aneurysms in 34 (32.1%), and an aneurysm of the sinus of Valsalva with aortic arch aneurysm in 1 (0.9%). The overall neurologic dysfunction rate was 6.6%. Early mortality was 18.8%. By multivariate analysis, circulatory arrest longer than 60 minutes and chronic renal failure were significant predictors of neurological dysfunction. Female gender, preoperative hemodynamic instability, circulatory arrest longer than 60 minutes, preoperative neurological dysfunction, and preoperative organ malperfusion were significant predictors of early mortality. We concluded that retrograde cerebral perfusion minimized neurological complications by preventing debris and air emboli and by providing adequate metabolic support in patients who needed circulatory arrest for surgical treatment of aortic pathology.

Techniques for retrograde cerebral perfusion in the treatment of aortic lesions via left thoracotomy.

Abstract Retrograde cerebral perfusion under deep hypothermic circulatory arrest is a simple and useful adjunct in aortic surgery and is performed by many surgeons in the treatment of aortic arch pathology. In recent years, this technique has been recommended in the surgery of distal arch and proximal descending aortic lesions through a left thoracotomy incision. The aim of the technique is to increase the right atrial pressure for retrograde cerebral perfusion. After cooling using femorofemoral bypass, circulatory arrest is initiated. The right atrial pressure is increased to 20 mmHg, and retrograde cerebral circulation results. In this article, five patients with distal aortic arch and proximal descending thoracic aortic lesions who were operated on by using this technique were evaluated. It is suggested that this technique can be used with a lateral thoracotomy approach that is suitable for procedures on a distal aortic arch and proximal descending aorta.

Intrapulmonary Hematoma and Hemothorax following Penetrating Chest Injury

Hemothorax and intrapulmonary hematoma were successfully treated in a 25-year-old male who suffered a penetrating chest injury. This very rare combination of clinical entities in the same patient is discussed in the light of pertinent literature.

Simple and Cost-Effective Gas Jet for Non-Pump Coronary Bypass Surgery

A gas jet is one method of achieving a bloodless surgical field. We describe a simple and cost-effective oxygen blower system for coronary artery bypass surgery performed without cardiopulmonary bypass.