A reevaluation of heparin requirements for cardiopulmonary bypass

We wished to determine if reduction in the standard heparin administration for cardiopulmonary bypass could be accomplished safely with the use of membrane oxygenators. An experimental study was designed to evaluate two different heparin administration protocols for cardiopulmonary bypass with hollow-fiber membrane oxygenators. Two groups of six pigs were submitted to hypothermic cardiopulmonary bypass (28 degrees C) for 3 hours, then rewarmed, decannulated, and reassessed after 1 hour. In group I (control) heparin was administered to maintain the activated clotting time in excess of 450 seconds; in group II activated clotting time was maintained between 250 and 300 seconds. The mean total heparin administered was 41,000 units in group I and 25,000 units in group II. Concentration of coagulation factors II, V, and VIII, fibrinogen, and platelet count were determined before, during, and 1 hour after bypass. No significant difference in any of these coagulation parameters was observed between the groups. The performance of the oxygenators was similar in both groups, with no evidence of thrombosis. Thus reduced heparin administration, enough to keep activated clotting time between 250 and 300 seconds, was not related either to major coagulation factors and platelet consumption or to derangements in the oxygenator's performance.

[The comparison of the binding of Ru486 to progesterone receptor of pituitary and endometrium in ovariectomized rat]

Following intramuscular injections of increasing doses of Ru486 (0.1 mg/kg-2 mg/kg), free progesterone binding sites remaining in pituitary and endometrium in estrogen-primed OVX rats decreased. Thirty minutes after administration of Ru486 (2 mg/kg) the binding sites of progesterone receptor in both tissues showed a significant initial decrease, and then gradually reached the lowest level in 2 h. Afterwards the levels of progesterone receptor began to increase. The results suggested that Ru486 could interact with progesterone receptor in both tissues. However, the binding ability of Ru486 for different tissue was not exactly the same, and Ru486 binding to the progesterone receptor in endometrium might be easier.

Cardiopulmonary exercise testing after single and double lung transplantation

The cardiopulmonary response to exercise was investigated in six single and six double lung transplant recipients using a three-minute incremental work rate protocol on a cycle ergometer. Maximum VO2 averaged 44.2 +/- 9.2 percent and 48.5 +/- 5.0 percent of predicted maximal VO2 in the single and double lung transplant groups, respectively. No evidence of ventilatory limitation to exercise was found in either group. Circulatory factors that may have limited exercise capacity included anemia and submaximal heart rates. There was a strong correlation between VO2/kg at venous blood lactate level of 2.2 mEq/L and vital capacity/body surface area in the single, but not in the double, lung recipients. Maximum VO2 in these lung transplant recipients was comparable to previously published values in heart-lung transplant recipients. The factors that limit maximum exercise capacity after lung transplantation deserve further study.

[Results of pulmonary angioplastic operations for cases of bronchogenic carcinoma]

Pulmonary artery reconstruction for bronchogenic carcinoma was performed in 36 patients (5.8%) in our department between 1955 and 1988 for the purpose of preservation of pulmonary function. Twenty-six patients had squamous cell carcinoma (72.2%) and 24 had Stage IIIA. The operative procedures were sleeve resection of the main pulmonary artery (P.A.) and end-to-end anastomosis in 20 cases, wedge resection of P.A. and transverse suture in 14 and window type resection of P.A. and patch closure in 2. In 28 patients bronchoplastic procedures were combined. Three patients (8.3%) died within 30 days after operation. Postoperative complications were relatively high in the patients with combined operations. The 5-year survival rates were 45.7%. Postoperative pulmonary functions were evaluated with spirometric examinations and pulmonary scintigrams. There were no differences in postoperative pulmonary functions between pulmonary angioplastic procedures and simple lobectomies.(ABSTRACT TRUNCATED AT 250 WORDS)

Recovery of elevated atrial natriuretic peptide in pressure-overload right heart failure

Elevation of the plasma concentrations of immunoreactive atrial natriuretic peptide (ANP) was observed in canine chronic right heart failure (RHF) secondary to right ventricular (RV) pressure overload. Pressure overload on the right heart was gradually increased using an inflatable cuff. The interval between banding and the onset of RHF was 152 +/- 52 days. Seventeen RHF dogs were produced and divided into Group I (n = 11) and Group II (n = 6). At the onset of RHF, Group I dogs were either sacrificed for study of the heart, or unbanded to allow recovery from RHF. The dogs in Group II were maintained in RHF for 3 additional months before being either sacrificed or unbanded. Following unbanding, the ANP level of Group I recovered from 108 +/- 36 (n = 11) to 20 +/- 6 pg/ml (n = 6) at 1 month and was maintained at 27 +/- 7 pg/ml (baseline, 21 +/- 5 pg/ml, n = 11) at 4 months. ANP levels of Group II declined from 165 +/- 55 (n = 6) to 87 +/- 2 pg/ml (n = 3) at 1 month and further decreased to 42 +/- 14 pg/ml (n = 3) 4 months after unbanding. Thus, compared to Group I, Group II had a high ANP level before unbanding and a delay in recovery of the ANP levels despite normalization of the right atrial pressure (RAP). Four months after release of pressure overload, the right atrial hypertrophy persisted in the unbanded dogs; however, Group I unbanded dogs showed a better reversal of the right atrial hypertrophy than Group II unbanded dogs.(ABSTRACT TRUNCATED AT 250 WORDS)

The effect of ischemic time and temperature on lung preservation in a simple ex vivo rabbit model used for functional assessment

Despite 25 years of research in lung transplantation, little progress has been made in methods for improving lung preservation. To evaluate many factors that may affect lung function after preservation, we have developed a simple, reliable, and inexpensive animal model. This consists of an isolated rabbit lung preparation perfused with blood and ventilated with a closed-circuit system. Heart-lung blocks were harvested and the left lung was assessed after ligation of the right pulmonary artery and right main-stem bronchus. On completion of a storage period, the left lung was ventilated and perfused with fresh rabbit venous blood at a rate of 40 ml/min for 10 minutes. Assessment of lung function included gas analysis of infused and effluent blood, oxygen uptake, mean pulmonary artery perfusion pressure, and mean airway pressure. A control group and six preservation groups were evaluated, each with different storage temperatures (38 degrees C, 34 degrees C, 23 degrees C, 15 degrees C, 10 degrees C, and 4 degrees C). For each temperature, ischemic periods ranging from 1 to 30 hours were studied. In the control group, the lungs were assessed immediately after being harvested. In the preservation groups, the lungs were kept partially inflated, stored at a predetermined temperature by immersion, and later assessed after variable ischemic periods. Our studies demonstrated the following: (1) The degree of impaired lung function produced by ischemia is reflected by a decrease in oxygen uptake and in oxygen tension of the effluent pulmonary venous blood and an increase in pulmonary artery perfusion pressure; (2) hypothermia improves ischemic tolerance; (3) preservation of lung at 10 degrees C is superior to preservation at 15 degrees C and 4 degrees C. This screening model has allowed evaluation of independent multiple factors and methods pertinent to lung preservation and enables one to assess lung function reliably and rapidly.

Influence of suture on bronchial anastomosis in growing puppies

A comparison study of synthetic nonabsorbable suture (nylon or Prolene) with absorbable suture (Dexon-S or Vicryl) for bronchoplasty was performed in growing puppies. The experiments (n = 15) were followed up for 185 to 381 days (average 323.8 days). Bronchoscopic and bronchographic studies were done at intervals. No stenosis was observed in the group receiving absorbable suture (n = 8), and the anastomoses grew proportionately with the proximal and distal bronchi. In the group receiving nonabsorbable suture (n = 7), variable stenoses developed; two moderate and two severe stenoses were observed during the early healing stage by bronchoscopic examination. In the sequential bronchograms, an increase of stenosis was noted in two dogs. The results suggest that absorbable suture is superior to nonabsorbable suture in pediatric bronchoplasty.

Traumatic disruptions of right upper bronchus and truncus intermedius in a five-year-old boy

A case of uncommon ruptures of right upper bronchus and truncus intermedius in a 5-year-old boy is presented. Two operations provided bronchial continuity, with insertion of an 18-gauge catheter required at the second operation. Problems in anastomosis and early postoperative management in small airways of growing children are also discussed.