The haemodynamic effects of intraaortic versus intravenous administration of protamine for reversal of heparin in man

A recent report suggests that there may be advantages of intraaortic (IA) versus intravenous (IV) administration of protamine for reversal of heparin at the end of cardiopulmonary bypass. Because complete haemodynamic measurements were not performed in that study, we prospectively and randomly assessed the effects of protamine sulphate administered via either route. Patients were studied in the period immediately following cardiopulmonary bypass. Heparin, 300 units . Kg-1, plus 150 units . Kg-1 when required, was administered to keep the activated clotting time greater than 400 sec. Protamine 3 mg . Kg-1 was injected over 30 sec. intravenously in the IV group (n = 5) and into the ascending aorta in the IA group (n = 5). There was a significant decrease in arterial blood pressure (28.6 per cent) from 109.2 +/- 5.6 mmHg (S.E.) systolic to 78.0 +/- 9.0 mmHg observed in the IA group one minute post protamine, which returned to baseline by 2.5 min (analysis of variance p less than 0.05). No significant hypotension was observed in the IV group. There was no significant change in heart rate, left atrial pressure, central venous pressure, systemic vascular resistance or cardiac index with either IA or IV protamine. In contrast to our recent study in pigs there was no significant change in pulmonary artery pressure, pulmonary vascular resistance or cardiac output with protamine. Results indicate that there are no haemodynamic benefits of IA vs IV injection of protamine.

The hemodynamic effects of intra-aortic versus intravenous administration of protamine for reversal of heparin in pigs

The hemodynamic effects of intra-aortic (IA) versus intravenous (IV) administration of protamine for reversal of heparin were studied in pigs. The animals were anesthetized with sodium thiopental, nitrous oxide, oxygen, and halothane. Twenty minutes after heparinization (3 mg/kg) the following hemodynamic parameters were measured: heart rate, arterial pressure, pulmonary artery pressure (PAP), left ventricular end-diastolic pressure, and cardiac output. Protamine sulfate (3 mg/kg) was injected over 30 seconds IV in Group I (five pigs) and into the ascending aorta (IA) in Group II (five pigs). After injection, the above measurements were repeated at 1.0, 2.5, 5, and 15 minutes. The hemodynamic effects of intravenous protamine (3 mg/kg) without prior heparinization were studied in Group III (four pigs). Groups I and II experienced a decrease in cardiac output (Group I, 14%; Group II, 29%) and a marked increase in PAP (Group I, 78%; Group II, 79%) and pulmonary vascular resistance (PVR) (Group I, 174%; Group II, 559%) which peaked at 1 minute after protamine injection (p less than 0.05). Cardiac output, PAP, and PVR returned to baseline within 15 minutes. Heart rate, arterial pressure, left ventricular end-diastolic pressure, and systemic vascular resistance (SVR) were unchanged. No hemodynamic abnormalities occurred in animals injected with protamine alone (Group III). It is concluded that IV or IA administration of protamine causes marked hemodynamic changes in heparinized pigs. This does not confirm a recent clinical study reporting stable hemodynamics after IA administration of protamine. The lack of circulatory effects of protamine in unheparinized pigs suggests that a protamine-heparin interaction may be involved.

Is new always better? A comparison of an established teaching method with a new teaching method in a surgical course

A comparison has been made between the effectiveness of a problem-solving exercise and a formal lecture on medical students' learning during their surgical attachment. The format of a clinical trail has been adapted. No difference has been shown in the knowledge conveyed by the two methods, although the students preferred the problem-solving exercise. No assessment has been made in this study of differences in the students ability to solve problems after exposure to different methods of teaching.

Effects of thiopentone on the canine coronary circulation in acute experimental myocardial ischaemia

Acute myocardial ischaemia was induced in five greyhounds by ligation of the anterior descending branch of the left main coronary artery. Changes in oxygen availability and consumption in the ischaemic area in response to thiopentone 10 mg kg-1 were compared with corresponding changes in non-ischaemic myocardium supplied by the circumflex artery. Despite a 40% reduction in arterial pressure, there were no significant changes in the oxygen availability/consumption ratio in either normal or ischaemic areas.

Rectal strictures associated with the intra-uterine contraceptive device

Two cases of stricture of the mid-rectum following extensive pelvic cellulitis due to the use of an intra-uterine contraceptive device (IUCD) are presented. The resulting dense circumferential extrarectal strictures failed to respond to treatment by proximal colostomy and antibiotic therapy and required difficult corrective resection. These are contrasted with an example of the more common upper rectal strictures associated with intraperitoneal sepsis of gynaecological origin, in this case pyosalpynx. Circumferential and transmural spread of inflammation tends to be limited by peritoneal reaction and the resulting strictures (which may be radiologically as severe as those in the mid-rectum) are often readily managed by simple removal of the source of infection. Thus, it appears that simple anatomical factors may be responsible for the differing pathologies seen in the two sites, and different management problems encountered within the two types of strictures.

Gastric-juice enzymes--an aid in the diagnosis of gastric cancer?

Lactic dehydrogenase (LDH) and beta-glucuronidase concentrations were measured in the resting gastric juice of 113 patients presenting with dyspepsia. All patients were investigated by double-contrast barium meal, endoscopy with biopsy, and, when appropriate, by laparotomy. In all patients tested there was a positive correlation between LDH and beta-glucuronidase concentrations. An index derived from the two enzyme activities correctly predicted the presence of gastric carcinoma in 41 out of 42 cases, and identified the only 2 cases of early gastric cancer in the series. There were 13 (11.5%) false-positive results, all in cases with extensive intestinal metaplasia, a change which may be associated with an increased risk of gastric malignancy. The measurement of gastric-juice enzymes is useful in the diagnosis of gastric cancer and may be of value in the identification of high-risk groups. The test is easily performed, inexpensive, and reproducible.

Halothane improves the balance of oxygen supply to demand in acute experimental myocardial ischaemia

Acute myocardial infarction was induced by ligation of the anterior descending branch of the left main coronary artery in greyhound dogs anaesthetized with pentobarbitone. Blood flow in the area of ischaemia was measured by xenon clearance and compared with flow in the circumflex artery measured with electromagnetic flow meters. Halothane 1% produced an approximate 40% reduction in flow to both ischaemic and normal areas in association with a 20% reduction in collateral perfusion pressure and a 40% reduction in mean arterial pressure. Comparison of the percentage change in the ratio of oxygen availability/consumption in response to halothane revealed a significant difference between the ischaemic and the normal areas. The former increased to 113 +/- 9.3% (mean +/- SEM) whilst the latter decreased to 91 +/- 5.02%. This suggests that, in the non-failing heart, halothane improves oxygenation in areas of acute myocardial ischaemia.

A program for correction of ear perforations in Navajo Indian children

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Vitamin C and acute illness in Navajo schoolchildren

To evaluate earlier observations, including our own, showing usefulness of vitamin C for managing the common cold, we performed a double-blind trial of vitamin C versus placebo in 868 children. There was no difference in number becoming ill (133 versus 129), number of episodes (166 versus 159) or mean illness duration (5.5 versus 5.8 days) between the groups. Children receiving vitamin C had fewer throat cultures yielding beta-hemolytic streptococcus (six versus 13, P less than 0.10), but no difference in overall complicated illness rate (24 versus 25). Plasma ascorbic acid levels were higher in the vitamin group 24 to 26 hours after supplementation (1.28 versus 1.04 mg per 100 ml, P less than 0.01). Children with high plasma ascorbic acid concentrations had longer mean illness (6.8 versus 4.0 days, P less than 0.05) than those with low levels. Vitamin C does not seem to be an effective prophylactic or therapeutic agent for upper respiratory illness.

Clearance of Fe59-labelled erythrocytes from normal and inflamed rabbit knee joints. II. Autoradiographic and histological studies

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