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Biomedical subjects

T Hitchcock

Publications and source records attributed to T Hitchcock.

9 recordsLinked to original sources

Observational study of prehospital delays in patients with chest pain.

OBJECTIVE: To define and measure patient reported prehospital delay in presentation to the emergency department with chest pain and identify simple strategies that may reduce this delay. The authors investigated the null hypothesis that the patients choice of service to call for acute medical help has no effect on the timing of thrombolysis. METHOD: A prospective observational study of prehospital times and events was undertaken on a target population of patients presenting with acute chest pain attributable to an acute coronary syndrome over a three month period. RESULTS: Patients who decided to call the ambulance service were compared with patients who contacted any other service. Most patients who contact non-ambulance services are seen by general practitioners. The prehospital system time for 121 patients who chose to call the ambulance service first was significantly shorter than for 96 patients who chose to call another service (median 57 min v 107 min; p<0.001). Of the 42 patients thrombolysed in the emergency department, those who chose to call the ambulance service had significantly shorter prehospital system times (number 21 v 21; median 44 v 69 min; p<0.001). Overall time from pain onset to initiation of thrombolysis was significantly longer in the group of patients who called a non-ambulance service first (median 130 min v 248 min; p=0.005). CONCLUSIONS: Patient with acute ischaemic chest pain who call their general practice instead of the ambulance service are likely to have delayed thrombolysis. This is likely to result in increased mortality. The most beneficial current approach is for general practices to divert all patients with possible ischaemic chest pain onset within 12 hours direct to the ambulance service.

Adult↗

Evidence, expertise and the emergency physician: doctors should anticipate legal reform in their expert evidence.

The court system is particularly dependent on expertise in science and medicine. Medical experts should be aware that their legal evidence has the potential to work against justice as there are partisan selection, financial, and adversarial pressures; and laws of evidence which allow legal evidence to be admissible without definition of its medical-evidence base. Currently the main checks on an expert's legal evidence are the professional integrity of the expert, and cross-examination. However, there is good reason to expect reform of the laws of legal evidence to define objective criteria for the admissibility of scientific legal evidence. In anticipation of these reforms, emergency physicians appearing in court should address the medical-evidence base of their legal evidence.

Australia↗

Spontaneous pneumomediastinum, pneumothorax and ecstasy abuse.

A case report is presented of a patient with bilateral pneumothoraces and spontaneous pneumomediastinum associated with ecstasy use. Pneumothorax and spontaneous pneumomediastinum should be considered in an ecstasy user who complains of chest pain, neck pain or shortness of breath.

Adolescent↗

Platelet-activating factor antagonism and streptokinase-induced hypotension in clinical acute myocardial infarction.

Continuing efforts are being made to improve thrombolytic therapy for acute myocardial infarction (AMI). The rate of streptokinase (SK) infusion is commonly limited by the hypotension that is induced. If this could be avoided, an accelerated regimen of SK could be given, analagous to that used for other thrombolytic agents such as alteplase. The mechanism of the SK-induced hypotension is unknown, but there is some evidence that platelet-activating factor (PAF) plays a role. The potent PAF receptor antagonist lexipafant (10 mg) (n=35), or matching placebo (n=36), was administered intravenously over 5 min, in a randomized double-blinded protocol, to consecutive patients about to receive SK for AMI; all but three had inferior MI, because of the preference for strategies other than SK therapy in patients with anterior MI. The rate of infusion of SK was set to give 1.5x10(6) units over 30 min, anticipating significant hypotension. Blood pressure fell sharply over the first 10 min of SK administration. The maximum fall in systolic blood pressure occurred between 8 and 12 min, and averaged 43+/-28 mmHg (mean+/-S.D.) and 40+/-26 mmHg in patients given placebo and lexipafant respectively. Systolic pressure having fallen to <90 mmHg, according to protocol the SK administration rate was reduced in 21 of 36 (58%) of patients given placebo and in 19 of 35 (54%) of patients given lexipafant. The total SK dose was given to all subjects over 40.3+/-17.5 and 40.2+/-13.4 min for the placebo and lexipafant groups respectively. Peak and time integrals of creatine kinase were not different in the two groups. There were no adverse effects attributable to lexipafant. It is concluded that the PAF receptor antagonist lexipafant has no significant effect on SK-induced hypotension and does not facilitate an accelerated regimen of administration.

Aged↗

Time delay in the treatment of acute myocardial infarction (AMI): a comparison of primary percutaneous transluminal coronary angioplasty (PTCA) with thrombolysis.

BACKGROUND: If primary percutaneous transluminal coronary angioplasty (PTCA) cannot be performed within times comparable to thrombolysis, the possible advantages of that management may be offset by the logistic difficulties associated with its delivery. AIM: To measure and compare the time delay involved in administration of thrombolysis and primary PTCA over a one year period and examine causes for delay greater than 60 minutes. METHOD: Prospective data collection on all patients treated with primary PTCA or thrombolysis. A quality improvement process was applied. RESULTS: Eighty-five patients were treated with thrombolysis with a delay of 39 +/- 8 (SD) minutes, 12 patients being treated more than 60 minutes after presentation. Primary PTCA was used in 79 patients with a delay of 48 +/- 12 (SD) minutes, 21 patients being treated after more than 60 minutes. Time delays in the two management groups were significantly different (p = 0.03) but that in primary PTCA during routine hours was not significantly different from that in thrombolysis treated patients (p = 0.07). Causes for revascularisation delay greater than 60 minutes from presentation are discussed. CONCLUSIONS: With appropriate facilities and organisation, patients with acute myocardial infarction presenting within normal working hours can be treated with primary PTCA without compromising their care due to time delay. Many patients managed with primary revascularisation by thrombolysis or primary PTCA with a delay of more than 60 minutes have identifiable clinically appropriate delays.

Angioplasty, Balloon, Coronary↗

Bell's palsy treatment with acyclovir and prednisone compared with prednisone alone: a double-blind, randomized, controlled trial.

In a double-blind study, we compared the final outcome of 99 Bell's palsy patients treated with either acyclovir-prednisone (53 patients) or placebo-prednisone (46 patients). For patients receiving acyclovir, the dosage was 2,000 mg (400 mg 5 times daily) for 10 days. Electrical tests included electroneurography and the maximal stimulation test. Univariate comparisons of outcome and electrical tests between the two groups were made with chi 2 analysis, Fisher's exact test, and t-tests. The outcome in acyclovir-prednisone-treated patients was superior to that in placebo-prednisone-treated patients. Treatment with acyclovir-prednisone was statistically more effective in returning volitional muscle motion (recovery profile of 10; p = .02) and in preventing partial nerve degeneration (p = .05) than placebo-prednisone treatment. The t-tests indicated that the recovery profile and index means were significantly better for the acyclovir-treated group (recovery profile t = 1.99, p = .051; recovery index t = 2.10, p = .040). We conclude that acyclovir-prednisone is superior to prednisone alone in treating Bell's palsy patients and suggest that herpes simplex is the probable cause of Bell's palsy.

Acyclovir↗

Common principle of guidance by echolocation and vision.

1. Using echolocation, bats move as gracefully as birds through the cluttered environment, suggesting common principles of optic and acoustic guidance. We tested the idea by analysing braking control of bats (Macroderma gigas) flying through a narrow aperture with eyes covered and uncovered. 2. Though braking control would seem to require rapid detection of distance and velocity and computation of deceleration, simpler control is possible using the tau function of any sensory variable S that is a power function of distance to aperture. Tau function of S is tau (S) = S/S (the dot means time derivative). Controlled braking is achievable by keeping tau (S) constant. 3. Previous experiments indicated the tau (S) constant procedure is followed by humans and birds in visually controlling braking. Analysis of the bats' flight trajectories indicated they too followed the braking procedure using echolocation. 4. The tau function of echo-delay or of echo-intensity or of angle subtended by directions of echoes from two points on the approach surface could be used to control braking. Aperture size was modulated during flight on some trials in an attempt to test between these possibilities, but the results were inconclusive.

Animals↗