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Biomedical subjects

D B Frewin

Publications and source records attributed to D B Frewin.

At least 55 records · Page 3Linked to original sources
PubMed1987

Fetal heart rate and maternal cardiovascular and catecholamine responses to dynamic exercise.

Fourteen women performed treadmill exercise for continuous 10-minute periods at levels of 2, 3 and 4 mets in the second and third trimester of pregnancy and again postpartum. The percentage increase in heart rate in response to exercise was similar during pregnancy and postpartum while systolic blood pressure was increased only during pregnancy. Maternal plasma noradrenaline levels at peak exercise increased 64% (p less than 0.005), 42% (p less than 0.005) and 29% (NS) in the 3 studies respectively compared to resting levels at these times. Ten women experienced increased uterine activity during the exercise or recovery periods. Fetal heart rate was increased (p less than 0.05) by exercise but this was independent of uterine contractions and plasma noradrenaline levels.

Adult↗
PubMed1986

Accidental coadministration of intravenous aminophylline and theophylline by mouth: a hazardous practice.

Eight patients who inadvertently received theophylline by mouth and aminophylline by the intravenous route together were reviewed by the Clinical Pharmacology Service of the Royal Adelaide Hospital because their serum theophylline levels were in excess of the stated therapeutic range. Six of these patients were severely compromised by their high theophylline level, and two of them, who had advanced obstructive lung disease and respiratory failure, died shortly after the drug levels were detected. Oversights of this nature can arise during the early stages of a patient's hospital admission and when medical staff changes occur. All patients who receive aminophylline by the intravenous route must be kept under close surveillance to ensure that theophylline formulations are not given by mouth concurrently.

Accidents↗
PubMed1986

Histamine levels in human synovial fluid.

Histamine levels have been measured in plasma and synovial fluid (SF) obtained from patients with various arthritides, using a radioenzymatic assay procedure. The concentration of the amine in the plasma of these patients was, in general, found to be considerably greater than that seen in a group of control patients without inflammatory joint disease. SF always contained higher levels of histamine than corresponding plasma samples. The results of our preliminary study suggest that the production of histamine within the synovium may be an important factor in the genesis of joint effusions.

Arthritis↗
PubMed1985

A comparative study of techniques of postoperative analgesia following caesarean section and lower abdominal surgery.

A double-blind, within-patient trial was carried out to compare intramuscular pethidine 100 mg, epidural pethidine 50 mg and epidural bupivacaine 25 mg for pain relief on the day after caesarean section or lower abdominal gynaecological surgery. Analgesia was assessed on a visual analogue pain scale. Forced expiratory volume in one second (FEV 1.0) and venous plasma catecholamine levels were measured immediately before and approximately thirty minutes after each treatment. At the completion of the study the treatments were ranked in order of patient preference. Nineteen patients completed the trial. Analgesia provided by epidural pethidine 50 mg was superior to intramuscular pethidine 100 mg (p less than 0.05) but not statistically better than epidural bupivacaine. There was no significant difference in the duration of analgesia between the active treatments. A mean increase in FEV 1.0 of 18% occurred after both of the epidural treatments, but this did not achieve statistical significance. There was no significant change in catecholamine levels after any of the treatments. Epidural pethidine was preferred by patients over and above intramuscular pethidine and epidural bupivacaine (p less than 0.05).

Anesthesia, Epidural↗
PubMed1985

Plasma histamine levels following administration of radiographic contrast media.

The effect of two conventional high-osmolality and two new low-osmolality contrast media on plasma histamine levels has been examined. The study population included 25 patients undergoing intravenous urography with Urovison 58% (sodium and meglumine diatrizoate), 24 patients receiving intravenous Hexabrix 320 (sodium and meglumine ioxaglate) for urography, 16 patients receiving intravenous Iopamiro 370 (iopamidol) for urography and 12 patients receiving Urografin 76% (sodium and meglumine diatrizoate) for coronary angiography. Seventy-four percent of the 77 patients studied suffered adverse reactions ranging from a feeling of warmth and nausea to laryngeal oedema and bronchospasm. Hexabrix 320 and Iopamiro 370 were associated with the least patient discomfort. All contrast agents usually produced a rise in plasma histamine following injection (Iopamiro 370 causing the least change) and the histamine levels then fell towards preinjection values over a space of about 10 minutes. No relationship was observed between the magnitude of the increase in histamine and the severity of the reaction that occurred. However, a relationship was suggested between the mean peak plasma histamine level achieved and the occurrence of a Grade II reaction (i.e., dry retching/vomiting, mild urticaria or rash). These findings raise the probability that histamine contributes to the more severe grades of reaction to radiographic contrast media.

Contrast Media↗
PubMed1984

Changes in plasma catecholamine levels during hemodialysis.

The plasma concentrations of dopamine (DA), adrenaline (AD) and noradrenaline (NA) were measured during 29 routine hemodialysis (HD) treatments on 13 patients to determine whether any changes occurred in the concentrations of these substances during HD. All of the 13 patients studied demonstrated a fall in mean arterial pressure (MAP) when HD was commenced. Decreased concentrations of all three catecholamines were also demonstrated after the first hour of dialysis. Plasma AD rose after two hours, but NA and DA were still significantly lower than pre-dialysis values at the end of HD. Study of 12 further patients during the first hour of HD confirmed that the NA level had fallen significantly by the fifteenth minute of HD, while the DA and AD levels took somewhat longer to fall. Both NA and DA were present in the dialysate in substantial amounts. Although the fall in MAP which accompanies HD is probably multifactorial, the loss of plasma catecholamines during HD may possibly contribute to the hemodynamic changes.

Adult↗
PubMed1984

The effects of gallamine and a mixture of pancuronium and alcuronium on the pressor and plasma catecholamine responses to tracheal intubation.

Tracheal intubation can be accompanied by significant increases in arterial pressure, heart rate and the plasma levels of noradrenaline and adrenaline. The drugs used at induction can enhance or attenuate these responses. In nine patients who had received gallamine, intubation was associated with a 45% rise in mean arterial pressure, a twofold rise in plasma adrenaline and a 49% rise in plasma noradrenaline concentration. When a mixture of pancuronium and alcuronium (in a ratio of 4:10 by weight) was used in ten patients, blood pressure fell 24% after induction and rose 49% after intubation. A 24% rise in plasma noradrenaline in response to intubation was also observed. Compared with pancuronium alone, the use of the mixture attenuates the rise in blood pressure and noradrenaline concentration associated with intubation but does not abolish them. In addition, the mixture was associated with a significant fall in blood pressure between induction and intubation, whereas this was not found with gallamine.

Adult↗
PubMed1983

Sea water. A novel self-medication for orthostatic hypotension.

We report the case of a patient who ingested sea water to combat disabling postural hypotension secondary to autonomic failure. While drinking approximately 900 mL of brine each day he had no symptoms and felt well. Serum biochemical analysis showed a very significant hyperchloraemia. Persistent diarrhoea eventually forced the patient to discontinue this most unorthodox form of treatment.

Autonomic Nervous System Diseases↗
PubMed1983

Effects of pancuronium and alcuronium on the changes in arterial pressure and plasma catecholamine concentrations during tracheal intubation.

The changes in the plasma concentrations of noradrenaline, adrenaline and dopamine, during tracheal intubation, were studied in 17 patients. Nine patients received pancuronium and eight alcuronium to produce neuromuscular blockade. In the patients receiving pancuronium, intubation of the trachea was accompanied by an increase in mean arterial pressure, and in the plasma concentrations of noradrenaline and adrenaline. In the alcuronium group, there were no significant changes in the plasma concentrations of any catecholamine, nor any change in mean arterial pressure in response to intubation of the trachea.

Adult↗
PubMed1983

The role of adrenal medullary catecholamine release in the response to a cold pressor test.

We studied the effects of a cold pressor test on the plasma catecholamine levels of ten patients undergoing coronary angiography, to determine whether the pressor changes were related to adrenergic activity. To investigate the relative contribution of adrenal medullary catecholamine release, we subjected two adrenalectomised volunteers to the same test. Arterial blood was assayed for dopamine (DA), adrenaline (A) and noradrenaline (NA). We found significant rises in the levels of all three catecholamines in the angiography patients, accompanied by a significant elevation in arterial blood pressure. In both the adrenalectomised patients a rise in blood pressure was seen but no significant rise in plasma catecholamines could be demonstrated. We postulate that although adrenal medullary catecholamine release occurs in response to the cold pressor test, the blood pressure elevation is independent of such adrenal activity. Sampling radial arterial blood may not reflect changes in plasma levels of peripherally released NA.

Adrenal Medulla↗
PubMed1983

The effects of suxamethonium and D-tubocurarine on the pressor and plasma catecholamine responses to tracheal intubation.

Changes in mean arterial pressure (MAP) and plasma catecholamine concentrations in response to endotracheal intubation were examined in 8 patients who had received d-tubocurarine and 10 who had received suxamethonium. MAP fell after induction of anaesthesia and administration of the relaxant by a mean of 11 mmHg in those who had received suxamethonium and 19 mmHg in those who had received d-tubocurarine (p less than 0.05 for each). MAP rose sharply when the trachea was intubated, by a mean of 29 mmHg for the suxamethonium group, and 35 mmHg for the curare group (p less than 0.001 for each). A significant rise in plasma noradrenaline was also noted after intubation in each group, 51% (p less than 0.01) for the suxamethonium group and 28% (p less than 0.05) for the d-tubocurarine. The results suggest that the fall in MAP after administration of d-tubocurarine does not attenuate the pressor response associated with intubation.

Adult↗
PubMed1983

Phenytoin and postoperative epilepsy. A double-blind study.

A double-blind trial of phenytoin therapy following craniotomy was performed to test the hypothesis that phenytoin is effective in reducing postoperative epilepsy. A significant reduction in the frequency of epilepsy was observed in the group receiving the active drug up to the 10th postoperative week. Half of the seizures occurred in the first 2 weeks and two-thirds within 1 month of cranial surgery. High rates of epilepsy were observed after surgery in patients with meningioma, metastasis, aneurysm, and head injury. Routine prophylaxis with phenytoin (in a dosage of 5 to 6 mg/kg/day) would seem to be indicated, particularly in high-risk patients and, where possible, this treatment should be started 1 week preoperatively. Seizure control is best when therapeutic levels of phenytoin are maintained.

Clinical Trials as Topic↗
PubMed1982

Therapeutic drug monitoring: a survey of sub- and supra-therapeutic serum drug levels in a large teaching hospital.

One thousand five hundred serum drug levels lying outside the defined therapeutic range have been followed up by the clinical pharmacology service at the Royal Adelaide Hospital over a thirteen month period. It was found that digoxin, phenytoin and theophylline were the most frequently monitored drugs. Blood levels outside the therapeutic range tended to be on the high side with digoxin, but were usually sub-therapeutic for the other two. Drug related toxicity was observed in 11.2 percent of those with a high serum level. Several potential drug interacting situations were also noted during the study. The value of therapeutic drug monitoring, to maximise efficacy of therapy and minimise side effects, is stressed. However, correct blood sampling, based on a knowledge of the clinical pharmacology and pharmacokinetics of the drug, must be performed in order to obtain optimal benefit from this exercise.

Carbamazepine↗