Pentti Kärkölä

Infection Prophylaxis in Pulmonary Surgery: A Randomized Prospective Study

A prospective randomized study to evaluate the efficacy of antibiotic prophylaxis against postoperative infections was carried out on 120 patients undergoing pulmonary operations. The patients were randomized into two groups of 60 patients each. One group received doxycycline (deoxytetracycline) prophylaxis for five days, and the other received cefuroxime (a second-generation cephalosporin) for one day. The groups were comparable with regard to age, sex, common risk factors, diagnosis, and operative procedures. A reduction in the infection rate was noted in the cefuroxime group (10/60) compared with the doxycycline group (19/60), but the difference was not statistically significant (p = 0.055). In major infections (empyema and pneumonia) there was no difference between the groups (4/60 in the cefuroxime group and 5/60 in the doxycycline group), but a significant (p less than 0.05) reduction was noted in minor infections (6/56 and 14/55, respectively) such as lower respiratory tract infections and prolonged fever. There were no wound infections in the two study groups. There were significantly (p less than 0.05) fewer postoperative fever reactions (axillary temperature greater than 37.5 degrees C) in the cefuroxime group (30/60) compared with the doxycycline group (44/60). Both antibiotics were effective in preventing wound infections, but cefuroxime may also be beneficial in preventing minor respiratory infections. The bactericidal effect of cefuroxime may explain this finding.

One Turn More: Threshold Superiority of 3-turn versus 2-turn Screw-in Myocardial Electrodes

Epicardial electrodes are an alternative for patients in whom the transvenous approach presents technical difficulties. We have had clinical experience with two types of myocardial sutureless electrodes inserted in the anterior left ventricular wall: the 3‐turn screw‐in electrode (Medtronic 6917) was used in 209 patients from 1974 to 1977 and the 2‐turn screw‐in lead (Medtronic 6917 A) was used in 61 patients from 1978 to 1981. The initial threshold was equal and acceptable with both types of electrodes.

Calcium Microemboli and Microfilters in Valve Operations

Fatal microemboli occurred in 3 of 100 consecutive patients having aortic valve replacement; 2 occurred during perfusion before the microfilter era, and 1 occurred intraoperatively despite the use of in-line filters. In all 3 patients cerebral symptoms were present immediately postoperatively, and each died of severe brain damage. On postmortem examination cerebral calcium microemboli were verified in only 2 patients, although the brain of each patient contained minute infarctions. However, calcium particles were found in the kidneys of all 3 patients. Thus the kidneys proved to be the best place for detection of calcium emboli on postmortem examination. Although the microfilters currently available effectively prevent microemboli during extracorporeal circulation, the surgeon should be aware that embolization can also occur immediately after discontinuation of perfusion. The means of protecting the patient from this are discussed.

Surgery of Thoracoabdominal Aortic Aneurysms

Arteriosclerotic aneurysm of the thoracoabdominal aorta, involving one or more visceral branches, was successfully operated on in eight patients. Two of the aneurysms had ruptured. The left diaphragm-splitting thoracoabdominal incision through the 8th intercostal space, using a retroperitoneal route, gave unrestricted exposure. A temporary aortofemoral shunt effectively protected abdominal organs and spinal cord from perioperative ischemic damage. The step-by-step reattachment technique into ready-made side limbs in the woven Dacron graft ensured that visceral and renal ischemic times remained within acceptable limits. Perfusion cooling of the abdominal organs was done in one patient in whom shunt could not be used. A standby autotransfusion device was life-saving in another case. All the patients recovered without major complications. Moderate elevation was found as regards serum creatinine levels in seven patients and liver enzymes in four patients, but the values normalized within a month. No paraplegic complications occurred, although all bleeding intercostal and lumbar arteries were ligated intra-aneurysmatically in seven of the eight patients. Seven patients are well 20 to 60 months postoperatively, with patent and well functioning grafts. One patient died of lung cancer after 7 months. Four of the 18 revascularized arteries in three patients were shown by control angiography to be occluded, but without serious sequelae. Our experience suggests that most thoracoabdominal aortic aneurysms are suitable for surgical correction, with acceptable risk. Elective surgery is therefore recommended.

Liver Drug Metabolism in Patients Undergoing Open-Heart Surgery

The effect of open-heart surgery on the drug metabolism of the liver was investigated in 17 patients by using the rate of antipyrine elimination as an index. A correlation was found between the pre-operative heart size and the antipyrine elimination rate. In patients with a markedly dilated heart, the plasma antipyrine half-life was prolonged and apparent clearance significantly impaired. Immediately postoperatively, antipyrine elimination was impaired in all patients. Later, the drug metabolism improved in patients with atrial septal defect, changed temporarily in patients with aortic valve replacement, and remained unchanged in patients with mitral valve replacement. The results indicate that adaptive changes in drug metabolizing capacity occur in patients undergoing cardiac surgery. The changes are related to the type of lesion corrected, the pre-operative functional capacity of the liver, and the time lapse after surgery.

Survival after surgical treatment of lung cancer

All 205 patients operated on for primary pulmonary cancer at Oulu University Hospital in 1975-1977 were followed up for 10 years to evaluate the prognostic influence of factors such as lymph-node invasion, size of tumour and histologic type. Preoperative mediastinoscopy was performed on 186 patients (91.2%), and revealed no mediastinal metastases in 182. Nevertheless N 2 (mediastinal) lymph nodes were found in 36 cases at operation and N 1 (perihilar or ipsilateral) nodes in 42. Despite lobectomy or pneumonectomy, all 32 patients (17.2%) with false-negative mediastinoscopy died within a year (mean 7.2 months) of operation. Pneumonectomy was performed in 67 cases (29 right, 38 left), lobectomy or bilobectomy in 125 and exploratory thoracotomy in the remainder. Most of the tumours were epidermoid carcinoma (53.7%). Adenocarcinoma was present in 20%, and large-cell carcinoma and oat-cell carcinoma each in 11.7%. Survival rates were significantly higher in patients without vs. those with lymph-node metastases and in epidermoid or adenocarcinoma vs. small-cell carcinoma.

LIVER ENZYMES AND OXYGEN SUPPLY DURING PROLONGED EXTRACORPOREAL CIRCULATION WITH STANDARD FLOW RATES

In a random group of 20 dogs undergoing a 3-hour extracorporeal circulation bypass with a standard flow rate of 100 ml/min/kg, a significant relationship was observed between the changes in increased levels of SGOT, SGPT and BSP retention, in decreased levels of liver microsomal enzymes oxidizing chlorpromazine and pethidine and venous pH, pO2. and oxygen saturation and increased levels of venous pCO2. The conclusion was drawn that oxygen supply to the liver, hypercarbia and acidosis during cardiopulmonary bypass are partly responsible for these changes, and that haemolysis, haemo-dilution, anaesthesia and operative trauma also affect the serum enzymes.

Computed Tomography and Mediastinoscopy in the Assessment of Resectability of Lung Cancer

In order to assess the potential of computed tomography (CT) of the mediastinum and mediastinoscopy in the staging of lung cancer, 125 patients were examined. Of these, 104 underwent thoracotomy, at which there was no evidence of mediastinal tumour involvement in 79 while 25 patients had signs of tumour spread. The sensitivity and specificity of CT were 87.0 per cent and 95.8 per cent, respectively, in the detection of direct tumour extension with a mediastinal mass. When lymph node enlargement was the sole finding, CT did not provide any differentiation between benign and malignant lymphadenopathy. The mediastinal involvement was inaccessible on mediastinoscopy in 18 cases (72%). Despite the surperior sensitivity of CT it was often difficult to determine whether direct tumour infiltratin of mediastinal structures had occurred. It was concluded that CT is necessary for screening the entire mediastinum and, when it reveals no evidence of mediastinal tumour spread, mediastinoscopy will yield no further information. Mediastinoscopy will help to correctly identify accessible mediastinal lymph node involvement of the superior mediastinum and to define the mediastinal tumour invasion in doubtful cases.

Aortic Valve Replacement with the Björk-Shiley Tilting Disc Valve Prosthesis: Clinical Experiences in 50 Cases

Single aortic valve replacement with the Björk-Shiley tilting disc valve prosthesis has been performed in 50 patients since April 1971. None of the total of six deaths (12.0%) was attributable to malfunction of the prosthesis or to embolic complications. Follow-up examination showed insignificant or moderate prosthetic regurgitation in two patients and moderate paravalvular leakage in one patient. A slight intravascular haemolysis was found in two cases, one of them without marked regurgitation, and a slight reversible cerebral thrombo-embolism in two. Clinical improvement was observed in 43 of the 44 survivors during the 6 to 12 months of follow-up. Objective evidence of improvement was verified by cardiac catheterization following the replacement of aortic valve with the Björk-Shiley tilting disc prosthesis.

Lack of effect of ischemia and dipyridamole on prostacyclin production in arteriosclerosis obliterans.

Six patients with advanced arteriosclerosis obliterans in the lower extremities were subjected to an exercise test on a tread mill with and without dipyridamole treatment. Prostacyclin (PGI2) release was measured by the concentration of its stable metabolite, 6-keto-prostaglandin F1 alpha in plasma. All the patients suffered from ischemic pain during both tests, but no changes were seen in plasma 6-keto-PGF1 alpha. Dipyridamole did not affect the physical performance. Our results suggest that atherosclerotic vessels do not increase PGI2 production in response to ischemia and that a single dose of dipyridamole does not change PGI2 production.