Extracorporeal membrane oxygenation (ECMO) as lung or heart assist.

Extracorporeal membrane oxygenation (ECMO) may serve as extracorporeal lung assist (ECLA) in patients with acute respiratory failure (ARF) or as extracorporeal heart assist (ECHA) in patients with low output syndrome (LOS) after open heart surgery. From 1988 to 1992 seven patients underwent ECMO in our hospital; four suffered from ARF and three from LOS. Various bypass techniques were employed. Two ARF patients, aged 58 and 18 years, had veno-venous bypass; in the latter, ECMO was reinstituted as a veno-arterial bypass one week after weaning. In a three-year-old boy, the ECMO outflow tubing was primarily connected to the pulmonary artery, and shortly afterwards relocated to the common carotid artery. In a 31-year-old man with ARF, and three LOS patients, a 56-year-old woman, and two men aged 68 and 70 years, ECMO was veno-arterial with direct access to the ascending aorta. A heparin-coated system was used, and all but one patient, who was treated with warfarin, received a daily low dose of heparin, which was withdrawn after from one to nine days. Six patients were weaned off ECMO after 4.5 to 21 days. Three ARF patients recovered completely; the child died. In one LOS patient, ECMO was withdrawn due to a poor general condition. Two others were weaned off ECMO and the intra-aortic balloon pump, and the inotropic support was significantly reduced, but both died of multiple system organ failure. Although no firm conclusions can be drawn from these few case reports, the heparin-coated system used as ECLA appears promising, whereas ECHA seems to imply a poor prognosis in patients who are not candidates for cardiac transplantation.

[Extracorporeal membrane oxygenation. A therapeutic alternative in acute heart and/or pulmonary failure?]. / Ekstrakorporal membranoksygenering. Et behandlingsalternativ ved akutt hjerte- og/eller lungesvikt?

Extracorporeal membrane oxygenation was introduced as a supplement ot mechanical ventilation in the treatment of two patients with severe acute respiratory failure and as heart assist in one patient with acute refractory cardiac failure after open heart surgery. The system includes a membrane oxygenator and a roller pump. The whole circuit is coated with partially degraded heparin covalently bound to the surface (Carmeda Bioactive Surface), reducing the need of systemic heparinization to a minimum. In the first case of acute respiratory failure a veno-venous bypass was employed, with cannulas in the right atrium and the femoral vein. Given a blood flow through the circuit of 2.5 l/min, ventilator settings could be favourably reduced. The patient was weaned off the bypass system after six days, off the ventilator after 120 days, and recovered completely. In two cases the system served as partial venoarterial bypass, and blood was returned to the ascending aorta. A 31 year-old male victim of a smoke inhalation lung injury was on bypass for four and a half days. He recovered completely after another 17 days of mechanical ventilation. A 68 year-old man with pump failure after cardiac surgery needed extracorporeal support as heart assist for seven days. On the eighth day he was weaned off intra-aortic balloon-pumping as well. Unfortunately, he died of septicemia, with multiple organ failure, 13 days later. The heparin-coated extracorporeal membrane oxygenation system may represent a major advancement in the treatment of critically ill patients in need of cardiopulmonary assist.

Muscle relaxants change myocardial metabolism in patients with ischemic heart disease during high-dose fentanyl anesthesia.

Although not unanimously accepted, high-dose fentanyl anesthesia has been associated with hemodynamic stability and little derangement of myocardial oxygen balance. This apparent inconsistency inspired us to investigate the effects on cardiac function and myocardial metabolism of stepwise increasing doses of fentanyl, accumulating to 15, 30, and 50 micrograms.kg-1, with the least possible interference from other drugs. Subjects were unpremedicated patients with ischemic cardiac disease scheduled for coronary artery bypass grafting or major vascular surgery. In an initial study employing succinylcholine for muscle relaxation, we found that heart rate (HR), coronary sinus blood flow (CSF) and coronary vascular resistance (CVR) remained unchanged, while systemic arterial pressure (SBP), rate-pressure product (RPP), coronary perfusion pressure (CPP) and left ventricular work (LVW) decreased. Myocardial uptake of oxygen (MVO2) and free fatty acids (FFA) both decreased in a dose-dependent manner. Arterial lactate concentration and myocardial lactate uptake both increased. These findings opposed the postinduction myocardial ischemia noted by some other investigators. In most of these studies pancuronium bromide had been used for muscle relaxation. Since the latter agent has been claimed to increase cardiac work, a second group of correspondingly diseased patients was studied in which succinylcholine was replaced by pancuronium bromide. In this group HR, RPP, CSF and MVO2 all increased at the lowest dose of fentanyl and HR additionally also at 30 micrograms.kg-1. The cardiac index was higher in the pancuronium group at the lowest and middle dose steps of fentanyl. Lactate uptake decreased with higher doses of fentanyl and relative myocardial lactate extraction declined.(ABSTRACT TRUNCATED AT 250 WORDS)

Neisseria meningitidis infections in Northern Norway: an epidemic in 1974-1975 due mainly to group B organisms.

A severe epidemic of disease due to Neisseria meningitidis has been occurring in northern Norway since 1974. Based on bacteriological and clinical examination of cases during the 18 months between January 1, 1974 and June 30, 1975, an overall attack rate of 26.3 cases per 100,000 population per year has been calculated. The attack rates were highest in 1975 (total, 37.4 cases per 100,000 population; Troms County, 54.5) and in children younger than four years (total, 173.6; Troms County, 328.9). The epidemic shows a total case-fatality ratio of 14.1%. The highest case fatality ratio was recorded for patients older than 20 years (25.0%). Among the youngest children, cases were distinctly more frequent in males than females; in older children and adults, male patients had a clearly higher case-fatility ratio than female patients. Of the three serogroups of N. meningitidis, group B caused more cases of infection that groups A and C together. In addition, the causative meningococcal strains were almost uniformly resistant to high concentrations of sulfonamide. Both of these traits appear to have developed in northern Norway at or shortly before the time when the epidemic began.