Biomedical subjects
L Strunin
Publications and source records attributed to L Strunin.
Modern infusion pumps: are they accurate?
This study examined the volumetric accuracy of six infusion pumps currently available in Canada. Volumes delivered by all pumps over a range of 20-200 ml an hour were within five per cent of their indicated values. The pumps proved to be consistent and unaffected by the height of the infusion bag above the pump or by differing cannulae sizes. A discussion of some of the infusion methods for obtaining clinical accuracy is included.
A simple and safe method of anesthetizing infant rabbits for abdominal surgery.
There is a great lack of information about general anesthesia in small infant animals. We developed a safe method using Halothane to maintain anesthesia in 20 infant rabbits weighing 100-150 g. Halothane was administered through a modified T piece using a small finger cot in order to minimize the dead space of the system. Halothane concentrations of 0.5 to 1.5% were safe and efficient to perform a laparotomy and to keep the rabbits alive after surgery.
Etiology of halothane hepatotoxicity.
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A perspective on halothane-induced hepatotoxicity.
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A micro-computerized anaesthetic record system.
An anesthetic record system has been implemented using a micro-computer, rather than a larger computer system. The record system provides a wide range of functions, including record retrieval, random record processing, and the generation of graphical reports on the department's operating room performance. The steps taken in realizing this system are described, with emphasis on the preparatory decisions that must be made before computer programming can be undertaken. Adopting a modest straightforward design philosophy is shown to be an important pre-requisite to success.
Comparative trial of the effect of ranitidine and cimetidine on gastric secretion in fasting patients at induction of anaesthesia.
A comparative trial of the H2-receptor antagonists, cimetidine and ranitidine, on gastric pH and volume, was conducted in 168 healthy patients coming to elective surgery. The drugs were administered in random fashion either intravenously (ranitidine 50 mg or 100 mg, cimetidine 300 mg or placebo) or orally (ranitidine 150 mg, cimetidine 300 mg or placebo). The patients received the drugs or placebo 45 minutes to five hours before operation. After induction of anaesthesia, a nasogastric tube was passed and the stomach contents were aspirated. The volume and pH were measured. Those patients receiving ranitidine 50 or 100 mg or cimetidine 300 mg intravenously had statistically significantly higher gastric pH compared to those receiving placebo, but up to eight percent of patients has a pH less than 2.5. Oral administration of cimetidine 300 mg or ranitidine 150 mg were also superior when compared to placebo. However, 25 per cent of the patients receiving oral cimetidine had a pH less than 2.5; cimetidine orally was statistically significantly inferior to ranitidine 100 mg given intravenously. We conclude that the intravenous use of either ranitidine or cimetidine is an acceptable method to decrease the acidity of gastric contents before induction of anaesthesia. Orally, ranitidine appears to be a better choice than cimetidine in the doses studied. Both ranitidine and cimetidine need to be given at least 45 minutes before induction of anaesthesia to be effective; therefore the use of these agents to decrease the risk of acid pulmonary aspiration syndrome by no means obviates the need for proper anaesthesia technique during induction of anaesthesia.
Leakage of volatile anaesthetics from agent-specific keyed vapourizer filling devices.
Agent-specific keyed vapourizer filling devices were designed to ensure that an anaesthetic vapourizer is filled with the correct agent. Since there appear to be no reports of possible loss of volatile agent or operating room pollution resulting from either the design or patterns of use of these devices, measurements were made with three anaesthetic agents and two methods of use. First, two bottles each of methoxyflurane, enflurane and halothane were fitted with a suitable filling device and the weight of agent lost from each bottle over six weeks was measured. Bottle #1 of each agent remained without agitation between weighings; bottle #2 was tipped to mimic filling of a vapourizer. Weight loss over the six week period was 2.76 and 3.15 per cent of the halothane, 2.22 and 2.43 per cent of the enflurane, and 0.58 and 0.96 per cent of the methoxyflurane, for bottles #1 and #2, respectively. Second, pollution was measured with an infra-red analyser for halothane, using bottles #1 and #2, as described above, and a third bottle on which the filling device was replaced by the screw-on cap after each filling of the vapourizer. Vapour loss was undetectable for bottle #1, between 25 and 30 ppm for bottle #2, and between 350 and 400 ppm for bottle #3. Thus, although the design of the filling devices results in loss of the anaesthetic agent, this loss represents potential pollution only when the device is replaced by the screw-on cap between use. Therefore, when using filling devices, these should be left on the bottle of volatile agent between fillings to decrease operating room pollution.
Post-anaesthetic dental extraction analgesia: a comparison of paracetamol, codeine, caffeine (Solpadeine) and diflunisal (Dolobid).
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The oesophageal obturator airway.
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Prospective controlled trial of injection sclerotherapy in patient with cirrhosis and recent variceal haemorrhage.
64 patients with cirrhosis and recent variceal haemorrhage were studied in a prospective randomised trial of injection sclerotherapy by means of a flexible oesophageal sheath. 12 (33%) of the 36 patients in the sclerotherapy group, suffered further bleeds from varices compared with 19 (68%) of the 28 patients receiving standard medical treatment. The risk of bleeding per patient-month of follow up decreased more than threefold with sclerotherapy and the number of patients rebleeding after 2, 6, and 12 months was significantly reduced (p < 0.05). 1-year survival without further bleeding improved significantly with sclerotherapy (46% compared with 6%, p < 0.02), although the difference in overall survival assessed by cumulative life-table analysis was not statistically significant. The main complication of the technique was the development of oesophageal ulcers in some patients.
Clinical monitoring of intracranial pressure in fulminant hepatic failure.
Cerebral oedema is the commonest immediate cause of death in fulminant hepatic failure and an investigation was carried out to determine the value of monitoring intracranial pressure (ICP) and to examine the effects of ICP of dexamethasone therapy and mannitol administration. ICP values in 10 patients at the time of insertion of a subdural pressure transducer (grade IV encephalopathy) averaged 15.5 +/- SD 14.8 mmHg. Despite dexamethansone therapy, which had been started on admission, rises in ICP were subsequently observed in seven of the eight patients who died. In the two patients who survived, the highest reading were 47 and 35 mmHg. Mannitol consistently reversed or arrested ICP rises when pressure was < 60 mmHg. ICP monitoring provides additional information in the managment of patients and is essential if mannitol therapy is to be used.
A comparison of halothane and enflurance (ethrane) for out-patient dental anaesthesia.
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Pressure on the tracheal mucosa from cuffed tubes.
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Hazard of high-dose fentanyl.
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Blood carbon dioxide tension changes during hysteroscopy.
During hysteroscopy the uterus may be distended with carbon dioxide (CO2), nitrous oxide (N2O), or Hyskon (a high molecular weight dextran). An initial study in 27 patients (group 1) using arterialized venous blood samples demonstrated rises in carbon dioxide tension (PCO2) when N2O was insufflated by using a laparoscopy insufflating device--a constant-pressure, variable-volume gas source. Cardiovascular collapse occurred in one patient in this group, most probably as a result of macropulmonary emboli of N2O. The rise in PCO2 is accounted for by an increase in physiologic dead space. In another 24 patients (group 2) the gaseous media were introduced by using a constant-volume, variable-pressure gas source; this resulted in minimal changes in arterial PCO2. The choice of whether a gaseous or liquid distending medium is used for hysteroscopy is governed by the state of the endometrium. If a gaseous medium is indicated, then CO2 is preferable to N2O and should be introduced with a constant-volume, variable-pressure gas source.