The General Practice computer system project: a doctor's desktop for Australia.

The Australian Department of Health and Family Services engaged the IBM consulting practice to develop a functional specification and technical architecture for a General Practice computer system (GPCS) in January, 1997. The project was completed in September, 1997. This paper describes the rationale for development of the specification, the process that was undertaken and provides an overview of the completed specification and architecture. The paper also explores a number of issues related to computing in general practice which were raised during the consultative process, and considers factors which were found to be important in obtaining adoption and use of computer technology on the doctor's desk.

Combination therapy with ranitidine and pirenzepine for control of intragastric pH in the critically ill.

In a prospective study of pH control for stress ulcer prophylaxis, intermittent iv infusion of the anticholinergic drug pirenzepine maintained the intragastric pH above 4 in only one of 17 ICU patients, while similar administration of the H2-receptor antagonist ranitidine was successful in seven of 32 patients. This difference was not statistically significant. Of 15 patients in whom a maximum dose of 600 mg/day of ranitidine or 90 mg/day of pirenzepine failed to maintain pH, combination therapy was successful in 11, a significant (p less than .01) improvement. We conclude that neither ranitidine nor pirenzepine provides adequate control of pH for stress ulcer prophylaxis when used alone. If used together they are the most effective combination so far described for parenteral control of gastric pH in the critically ill. Regular monitoring of gastric pH is nevertheless essential to allow detection of therapeutic failures.

Pharmacokinetics of ranitidine in quadriplegics.

In a previous study we observed that quadriplegic patients were unresponsive to ranitidine given in high dose (600 mg day-1 intravenously) for prophylaxis of stress ulceration. The pharmacokinetics of 100 mg of intravenous ranitidine have therefore been studied in six male quadriplegic patients. Plasma drug concentrations declined in a biexponential fashion. The mean (+/- s.e. mean) distribution half-life was 9.42 (+/- 1.04) min. The terminal plasma elimination half-life 1.79 (+/- 0.12) h, the volume of distribution 103 (+/- 17) litres and total body clearance 663 (+/- 86) ml/min. These values are similar to those described in two published studies performed in normal male volunteers. This suggests that there is no pharmacokinetic reason for the quadriplegics to be resistant to ranitidine and the defect is likely to be related to vagal control of acid secretion.

Anaesthesia in an Australian private hospital: the consumer's view.

A survey of the patients' view of anaesthesia was carried out in a medium-sized metropolitan private hospital. The study was performed using a postoperative questionnaire. A two-week period was investigated, and data was obtained from 121 of 124 patients anaesthetised during that period. The results showed a very high degree of satisfaction with the anaesthetic services provided, although specific questioning revealed many minor complaints. The results are compared with previous studies done in public hospitals and show that from the patients' perspective, there were fewer complaints than have been noted in the other studies.

Randomized, prospective trial of cimetidine and ranitidine for control of intragastric pH in the critically ill.

Forty-eight critically ill patients in an intensive care unit were enrolled in a prospective study of stress ulcer prophylaxis. The H2-receptor antagonists cimetidine and ranitidine were used, patients being randomized on hospital number. Response was assessed by measuring gastric pH every 2 hours. The drugs were administered by intravenous infusion, and up to three dosage increments fo each of the drugs were titrated against the pH of the aspirated gastric juice. If one drug, in maximum dose, failed to maintain the pH above 4, the other drug was administered at maximum dose. If both drugs failed to achieve control of gastric pH, antacids were administered in an endeavor to ensure patient safety. Cimetidine was successful in maintaining the intragastric pH above 4, for the duration of the intensive care admission, in five of 28 patients. Ranitidine was successful in 10 of 20 patients. The difference between these two groups was statistically significant (p = 0.04). In patients in whom cimetidine therapy failed, ranitidine provided adequate control of pH in four of 13. Cimetidine controlled one of six patients who had failed to improve with ranitidine therapy. Plasma concentrations of both drugs were well above established acid inhibitory concentrations. However, even with much lower plasma concentrations of ranitidine, similar amounts of both drugs were present in the gastric juice, suggesting a possible explanation for the greater efficacy of ranitidine. We conclude that, although ranitidine is more effective than cimetidine, neither of these drugs is adequate for stress ulcer prophylaxis. If they ae used for this purpose in the critically ill patient, regular monitoring of gastric pH is essential to allow detection of therapeutic failures.

Initial assessment of acute haemorrhage.

The assessment of the patient with acute blood loss may be conveniently divided into three phases. The first involves the recognition that acute blood loss has occurred. Further assessment of the site and magnitude of the blood loss will continue in parallel with resuscitation. The second phase of the assessment is the localising of the source or sources of bleeding to allow for control of continuing loss and to plan definitive therapy for the control of ongoing haemorrhage if necessary. The third phase of assessment is to estimate the quantity of blood and fluid loss to allow for the rational planning of resuscitation. The third phase is divided into two sections: the first is the initial assessment of the magnitude of the loss, the second the ongoing assessment of the patient's status as resuscitation proceeds. Successful resuscitation depends on repeated assessment of the patient while treatment proceeds.

pH testing paper for measurement of intragastric acidity: an assessment.

Regular evaluation of the pH of aspirated gastric juice is an important part of the routine prevention of the stress ulceration syndrome. This study has examined the use of commercially available pH paper for this purpose. Both clear buffer solutions and samples of gastric aspirate were used to assess the reliability of four products, Merck Universal pH Indicator strips (Art. 9535), Lyphan Universal pH Indicator paper, Whatman Wide Range pH paper and Macherey-Nagel Universal pH paper. The results show that the Merck strips and Lyphan paper are very reliable for measuring gastric aspirate pH and that intensive care nursing staff can make accurate observations when using these papers.

The epidemiology and clinical features of anaphylactic reactions in anaesthesia.

Severe anaphylactoid reactions during anaesthesia in 116 patients are described. The majority of patients who reacted to induction agents had previous exposure to the drug, while the majority of patients who reacted to muscle relaxants had not. There was a statistically significant increased incidence of allergy, atopy, asthma and previous reactions in patients who had reactions compared with a control group undergoing uneventful anaesthesia. There was no correlation between abnormalities in immunoglobulins or resting complement levels and a history of allergy or atopy. Antihistamines, steroids and bronchodilators alone did not prevent reactions and three patients reacted to test doses with Althesin. Reactions usually occurred during induction of anaesthesia, but may occur at any time in the perioperative period. No one drug produced reactions that differed in severity or clinical features from any other drug. Clinical features included skin changes, oedema, cardiovascular collapse, bronchospasm, gastrointestinal symptoms, prolonged unconsciousness, convulsions and pulmonary oedema. Four patients died.

Fluorometric determination of "albumin-titratable bilirubin" in the jaundiced neonate.

We report a fluorometric technique for determination of albumin-titratable bilirubin in the jaundiced neonate. Although bilirubin alone has very little native fluorescence, considerable emission is observed in the presence of albumin under acid conditions. Analysis of the plasma sample alone and in the presence of excess human serum albumin solution appears to reflect the bilirubin tightly bound to albumin and the total serum bilirubin, respectively. The difference between these two values has been designated as "albumin-titratable bilirubin". Where the concentration of albumin-titratable bilirubin is considerable, a typical saturation effect is observed. In samples where the circulating bilirubin is strongly bound to endogenous alumin, no change in fluorescence is seen when exogenous albumin is added. Results correlate well with the clinical picture.

Further observations on the immunological induction of DNA synthesis in mouse peritoneal macrophages. Role of products of activated lymphocytes.

Subcutaneous injection of ovalbumin (OA) into mice immunized with OA in Freund's complete adjuvant was followed by an increase in the numbers of peritoneal macrophages synthesizing DNA, determined by autoradiography. The effect was immunologically specific. The increase was followed by an increase in the numbers of peritoneal macrophages; the numbers of peritoneal lymphocytes also increased. Injection of OA into immunized or normal mice was followed by a blood monocytosis. Increased DNA synthesis, determined by liquid scintillation counting, occurred in spleen or lymph node cells from immunized mice, cultured with OA. Diluted supernatants from such cultures, injected intravenously into normal mice, caused increases in the numbers of DNA-synthesizing peritoneal macrophages. Similarly, supernatants from concanavalin A stimulated spleen cells, freed of Con A, also caused an increase in DNA-synthesizing macrophages.