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B Urquhart

Publications and source records attributed to B Urquhart.

9 recordsLinked to original sources
PubMed1991

Haemodynamic effects and outcome analysis of hypotensive extradural anaesthesia in controlled hypertensive patients undergoing total hip arthroplasty.

We have examined the safety of induced hypotension produced by extradural anaesthesia in patients with medically controlled hypertension. The haemodynamic response to induced hypotension was assessed in 38 non-hypertensive and 31 controlled hypertensive patients. All received extradural anaesthesia to T4 or above which decreased mean arterial pressure to 52 mm Hg and 55 mm Hg in normotensive and hypertensive patients, respectively. Cardiac output (thermodilution) was maintained by low dose i.v. infusions of adrenaline (1-5 micrograms min-1). No differences in the haemodynamic response to induced hypotension were observed in hypertensive patients. Data were collected also from 987 consecutive patients (353 hypertensive and 634 non-hypertensive) undergoing total hip replacement. Patients with hypertension were significantly older (68 vs 60 yr; P less than 0.001) and had greater ASA ratings (P less than 0.001). The smallest recorded systolic pressures were reduced more in patients with hypertension (57% vs 52%, respectively; P less than 0.001). The mean duration of maintained intraoperative hypotension (100 and 98 min) and estimated intraoperative blood loss (278 vs 281 ml) were similar in each group. After operation, two patients developed myocardial infarctions. None developed acute renal failure or stroke. There were three deaths; one of a patient who had hypertension. This suggests that induced hypotension with extradural anaesthesia is a safe technique for patients with medically controlled hypertension undergoing total hip arthroplasty.

Adult↗
PubMed1991

Effect of hypotensive epidural anaesthesia on acetabular cement-bone fixation in total hip arthroplasty.

We selected 20 matched pairs of patients who had had total hip arthroplasty by the same surgeon using the same cemented technique. Matching was by age, sex, height, weight and diagnosis. One of each pair had received hypotensive epidural anaesthesia, with less than 300 ml blood loss: the other had normotensive general anaesthesia with more than 500 ml of blood loss. Early postoperative radiographs were evaluated independently by three blinded observers, using a scoring criteria which assessed the quality of the cement-bone interface. The results showed that patients who had received epidural anaesthesia had significantly better radiographic scores (p less than 0.02). Our findings suggest that hypotensive anaesthesia facilitates penetration of cement into bone.

Anesthesia, Epidural↗
PubMed1991

Effects of epidural anesthesia on the incidence of deep-vein thrombosis after total knee arthroplasty.

Epidural anesthesia has been reported to reduce the prevalence of deep-vein thrombosis after total hip arthroplasty compared with the prevalence after general anesthesia. However, the effect of epidural anesthesia on the rate of thrombosis after total knee arthroplasty has not been reported previously, to our knowledge. A review was conducted of 705 total knee arthroplasties (541 patients) that had been performed by a single surgeon between September 1984 and December 1988. During this period, the operative technique, the protocol for rehabilitation, and the regimen for prophylaxis against thromboembolism did not change meaningfully. The patients received either epidural or general anesthesia. Preoperative and postoperative perfusion scans of the lungs and a venogram of the lower limb or limbs that had been operated on were done for all patients. For the 227 patients who had received epidural anesthesia, the over-all rate of deep-vein thrombosis was 48 per cent, which was significantly lower than the 64 per cent incidence in the 264 patients who had received general anesthesia (p less than 0.0001). The greatest reduction was in the occurrence of proximal thrombosis, which was identified in 9 per cent of the patients who had had general anesthesia but in only 4 per cent of those who had had epidural anesthesia (p less than 0.05). The use of epidural anesthesia reduced the incidence of proximal thrombosis after both unilateral and one-stage bilateral arthroplasty.

Adult↗
PubMed1990

Extradural anaesthesia in patients with previous lumbar spine surgery.

We studied prospectively 1381 patients undergoing extradural anaesthesia for total hip or total knee replacement, to determine if extradural anaesthesia can be performed reliably in patients who have had previous lumbar spine surgery. Fifty-two of the 57 patients (91.2%) who had undergone lumbar spine surgery received a successful extradural anaesthetic, and 1307 of 1324 patients without previous back surgery had successful extradural anaesthesia (98.7% success) (P less than 0.0001). No late complications were observed. Causes for failure of extradural anaesthesia in patients who had previously undergone lumbar spine surgery included technical difficulty (three) and inadequate spread (two).

Anesthesia, Epidural↗
PubMed1980

Rat brain cyclic AMP levels and withdrawal behavior following treatment with t-butanol.

1. The time course development of physical dependence as assessed by the withdrawal reaction was identical for ethanol and t-butanol. 2. t-Butanol is most likely not metabolized by the liver and is eliminated from the rat 6 to 7% as rapidly as ethanol. 3. Blood and brain acetaldehyde could not be detected following treatment with t-butanol. 4. At the peak of withdrawal, cyclic AMP levels were indistinguishable from control values following treatment with either ethanol or t-butanol.

Acetaldehyde↗
PubMedDate not supplied

Increased specificity in measuring satisfaction.

The authors report a patient satisfaction study that addressed some of the methodological limitations of previous studies and attempted to increase the variance in satisfaction assessment by increasing the scope and specificity of inquiry. Same sex patient/therapist match, duration of therapy, individual therapy and treatment with staff social workers rather than psychiatric residents all were positively correlated with increased patient satisfaction. Satisfaction appeared to be a unitary dimension that could be tapped by a global score. Nonetheless, although overall satisfaction was high, one third of patients preferred an alternative treatment.

Adult↗
PubMedDate not supplied

Hemodynamic changes associated with tourniquet use under epidural anesthesia for total knee arthroplasty.

BACKGROUND AND OBJECTIVES: Epidural anesthesia is administered commonly for total knee arthroplasty, a procedure using a thigh tourniquet. Tourniquet use has been associated with intraoperative hypertension and with occasional circulatory collapse after deflation. The purpose of this study was to define the hemodynamic changes in this setting. METHODS: We prospectively studied 373 consecutive patients having a total knee arthroplasty performed under epidural anesthesia, with continuous electrocardiogram and radial artery pressure monitoring. Results were analyzed using Student's t-test, correlation coefficients, analysis of variance, or chi-square analysis. Alpha was set at 0.01. RESULTS: There was a 4 +/- 11 mmHg rise in mean arterial pressure throughout the period of tourniquet application (p less than 0.001); no clinically significant hypertension occurred. After tourniquet deflation, there was a 19.2 +/- 12% reduction in mean arterial pressure, occurring within one minute. The magnitude of mean arterial pressure reduction failed to correlate with any clinical parameter other than vasopressor use. There was a small subset of patients who had a fall in heart rate and a more profound degree of hypotension after tourniquet deflation, but these patients could not be identified before tourniquet release. CONCLUSIONS: In this setting, tourniquet-induced hypertension is rare. However, hypotension after deflation is common, occurs rapidly, and correlates poorly with clinical parameters.

Adult↗
PubMedDate not supplied

Hemodynamic response to low-dose epinephrine infusion during hypotensive epidural anesthesia for total hip replacement.

The hemodynamic response to reduction in blood pressure after epidural anesthesia in elderly patients is poorly defined. Therefore, hemodynamic measurements using radial artery and thermodilution pulmonary artery catheters were performed in 85 patients undergoing total hip replacement in whom blood pressure was allowed to decrease in order to minimize blood loss. Measurements were made in the lateral position prior to and after induction of epidural anesthesia to T4 or above when mean arterial pressure (MAP) had fallen to 50-55 mmHg. Four non-randomized groups of patients were identified: those requiring zero, less than 1 microgram/minute, 1-2 micrograms/minute or 2-5 micrograms/minute, respectively, of intravenous epinephrine to maintain MAP at 50-55 mmHg. In patients receiving no epinephrine, MAP, heart rate (HR), stroke volume (SV), cardiac index (CI), pulmonary artery diastolic pressure (PAD), left ventricular stroke work index (LVSWI) and systemic vascular resistance (SVR) fell significantly from baseline. Low-dose epinephrine infusions modified this response by increasing SV and CI and reducing SVR, but had little consistent effect on PAD, HR and LVSWI. Increases in SV and CI were significantly related to the dose of epinephrine administered. Low-dose intravenous epinephrine infusions preserve cardiac output during hypotensive epidural anesthesia in elderly patients.

Aged↗