Anaesthetic management of emergency caesarean section followed by pulmonary embolectomy.

This report discusses the anaesthetic management of a patient undergoing emergency Caesarean section followed by an open pulmonary embolectomy with cardiopulmonary bypass. This case was complicated by the major physiological alterations associated with pregnancy and delivery, massive blood loss, cardiac dysrhythmias, hypotension, and cardiac arrest. Both patients, mother and child, made a full recovery.

Oxygenation in patients with chronic airflow obstruction after cessation of exercise.

Although oxygenation has been widely investigated in patients with chronic airflow obstruction both at rest and during exercise, very little is known about their oxygenation in the postexercise recovery period. Recently, it has been shown that PaO2 may in fact be higher during the initial 20 to 120 seconds recovery phase, compared to rest and peak exercise levels. Since it is not established to what extent this improvement persists, we investigated the changes in oxygenation during this phase in patients with CAO. We measured arterial blood gas values, expired gases and ventilation at rest, peak exercise and during the first seven minutes of recovery in 18 male patients with moderate-severe CAO. Mean rest PaO2 (77 mm Hg) and peak exercise PaO2 (76 mm Hg) did not change significantly. Compared to peak exercise, PaO2 was significantly higher during recovery at one minute (93 mm Hg, p = 0.005) and at four minutes (91 mm Hg, p = 0.005), but not at seven minutes (86 mm Hg, p = 0.155) after exercise. All of the recovery PaO2 levels were significantly higher than resting PaO2. These results indicate that during the postexercise recovery period, oxygenation is better than at peak exercise or at rest. Regression analysis of the data predicts that oxygenation may return to resting levels 8 to 9 minutes after cessation of exercise.

Influence of the menstrual cycle on airway function in asthmatic and normal subjects.

Investigations of premenstrual asthma (PMA) have been based on studies of asthmatics already aware of a deterioration of asthma premenstrually. Little is known, therefore, about relationships between the menstrual cycle and airway function in asthmatics who do not complain of PMA or in normal subjects. We investigated airway function in both of these groups for three or four consecutive menstrual cycles. Daily records of asthma symptoms and peak expiratory flow rates were maintained by 11 asthmatics and 29 normal control subjects. Standard spirometry and serum estradiol and progesterone levels were measured during the follicular, midluteal, and late luteal phases of the menstrual cycle. Airway reactivity to methacholine was tested during the follicular and luteal phases. The normal group showed no significant changes in symptoms, peak flow rates, spirometric parameters, or airway reactivity. Although the asthmatic group also demonstrated no significant changes in spirometry and airway reactivity, asthma symptoms (shortness-of-breath, cough, wheeze, and chest tightness) deteriorated significantly (p less than 0.001) from the follicular to the luteal phase, as did the morning peak flows of the asthmatics (p = 0.045). Airway function and reactivity were not related to hormone levels in either group. This study indicates that asthmatics not previously aware of PMA will record a premenstrual worsening of asthma symptoms and peak expiratory flow rates. These changes are not related to a deterioration in spirometry and airway reactivity or to the absolute levels of circulating progesterone and estradiol.

Simultaneous use of membrane oxygenation and high-frequency jet ventilation in acute pulmonary failure.

A 16-yr-old female suffering acute, rapidly progressive combined respiratory and cardiac failure that was unresponsive to conventional volume-cycled ventilation, was stabilized with the simultaneous short-term use of veno-venous membrane oxygenation and high-frequency jet ventilation. Percutaneously introduced cannulas afforded rapid vascular access for membrane oxygenation, minimal wound problems during the perfusion, and easy decannulation. This is the first reported combined use of high-frequency jet ventilation and extracorporeal membrane oxygenation, and the first reported percutaneous initiation of veno-venous bypass. The patient remained alive and well 4 months after therapy.

Cimetidine prophylaxis for gastrointestinal bleeding in an intensive care unit.

The efficacy of cimetidine in the prevention of gastrointestinal haemorrhage in a general intensive care unit was evaluated in 221 patients by a placebo controlled double blind randomised study. Criteria for bleeding were (i) haematemesis or gastric aspirate greater than 50 ml fresh blood, (ii) melaena or fresh blood per rectum with an upper source verified by endoscopy if the gastric aspirate was clear, (iii) a fall in haemoglobin level greater than 2 g/dl in a 24 hour period associated with either 4+ occult blood in stools, or coffee ground gastric drainage of at least 100 ml. The drug and placebo groups were similar for age, sex, duration of study and risk factors. One hundred and fourteen received cimetidine and 107 placebo. Only 8% of the patients bled with no significant difference between the two groups (6/114 cimetidine, 11/107 placebo; p = 0.16). There was no correlation between the frequency of bleeding and either the number of risk factors per patient or the duration of intensive care unit stay. Thirteen patients died in each study group, resulting in overall mortality of 12%. The low incidence of haemorrhage, the lack of statistical benefit from cimetidine and the similar mortality all argue against the routine use of this drug in intensive care unit patients.

Dose-dependency of theophylline clearance and protein binding.

Dose-dependency in theophylline pharmacokinetics and protein binding characteristics was examined in 10 healthy male volunteers. Theophylline disposition was determined after an intravenous infusion of both 1 mg/kg and 6 mg/kg aminophylline in a randomised crossover study. There was considerable intrasubject variability in theophylline clearance but no significant dose-dependency. Theophylline protein binding was assessed by equilibrium dialysis at varying theophylline concentrations. The percentage of free non-protein bound theophylline was significantly increased at high theophylline concentrations. This increase in free theophylline would lead to a non-linear increase in the risk of toxicity with increasing drug concentration.

Measurement of cardiac output by carbon dioxide rebreathing.

Twenty patients were studied on a bicycle ergometer at rest and at varying workloads to compare methods of measuring cardiac output. In nine patients, a comparison of carbon dioxide rebreathing and dye dilution techniques for measuring cardiac output were made. In eleven patients, comparisons between carbon dioxide rebreathing, dye dilution, and direct oxygen Fick techniques were made. The cardiac output measured by carbon dioxide rebreathing was reproducible and compared well with both the dye dilution and direct oxygen Fick. The correlation coefficient for the relationship between carbon dioxide rebreathing and direct oxygen Fick cardiac outputs was 0.80 and between carbon dioxide rebreathing and dye dilution cardiac outputs was 0.75. The relationship between dye dilution and direct oxygen Fick cardiac output was 0.71. The carbon dioxide rebreathing technique is a safe, non-invasive and reproducible method to measure cardiac output. The results compare well with the cardiac output measured by either the direct oxygen Fick or dye dilution technique.

Palmitate incorporation in the lungs of dogs with granulomatous disease.

Moderate hypoxia did not influence the pulmonary incorporation of an intravenous dose of [1-14C]palmitate either in dogs with experimentally produced granulomatous disease or in normal controls. The lung weight in the diseased animals, was, on the average, double that of the controls. There was a proportionate increase in uptake of the radioactive label at 1 hr after infusion in the diseased lungs, hence the specific activity of labeled palmitate (counts per minute per gram of phospholipid) was no different in the two groups. Moreover, half the radioactivity of the phospholipids was recovered in palmitate separated from the phosphatidyl choline fraction in both diseased and normal lungs. Anatomic studies demonstrated increased numbers of Type II pneumocytes lining all alveolar air spaces in the diseased lung. Autoradiographic studies indicated the presence of labeled palmitate in the Type II cells, but not in the inflammatory cells of the granulomata. We conclude that the increased palmitate uptake in this disease is accounted for by the metabolic activity of the Type II pneumocytes.

Return to work after myocardial infarction.

One hundred and twelve patients who were 64 years of age or younger and who were employed at the time of their first myocardial infarction were studied to determine the vocational end-result following myocardial infarction. Ninety-seven patients were available for followup: 70 had resumed previous employment, nine were in physically less demanding work, seven were working part-time and 11 were unemployed. Four of the last group had adequate grounds for retirement, but seven were unemployed without adequate medical reasons. Poor medical advice and readily obtainable disability pensions appear to be the major factors responsible for unnecessary unemployment. It is apparent that expert cardiac evaluation followed by vocational assessment and assistance is required before classifying any patient as permanently unemployable.