Assessing and Improving Performance: A Longitudinal Evaluation of Priority Setting and Resource Allocation in a Canadian Health Region

Background: In order to meet the challenges presented by increasing demand and scarcity of resources, healthcare organizations are faced with difficult decisions related to resource allocation. Tools to facilitate evaluation and improvement of these processes could enable greater transparency and more optimal distribution of resources.

Methods: The Resource Allocation Performance Assessment Tool (RAPAT) was implemented in a healthcare organization in British Columbia, Canada. Recommendations for improvement were delivered, and a follow up evaluation exercise was conducted to assess the trajectory of the organization’s priority setting and resource allocation (PSRA) process 2 years post the original evaluation.

Results: Implementation of RAPAT in the pilot organization identified strengths and weaknesses of the organization’s PSRA process at the time of the original evaluation. Strengths included the use of criteria and evidence, an ability to reallocate resources, and the involvement of frontline staff in the process. Weaknesses included training, communication, and lack of program budgeting. Although the follow up revealed a regression from a more formal PSRA process, a legacy of explicit resource allocation was reported to be providing ongoing benefit for the organization.

Conclusion: While past studies have taken a cross-sectional approach, this paper introduces the first longitudinal evaluation of PSRA in a healthcare organization. By including the strengths, weaknesses, and evolution of one organization’s journey, the authors’ intend that this paper will assist other healthcare leaders in meeting the challenges of allocating scarce resources.

High performance in healthcare priority setting and resource allocation: A literature- and case study-based framework in the Canadian context

Priority setting and resource allocation, or PSRA, are key functions of executive teams in healthcare organizations. Yet decision-makers often base their choices on historical patterns of resource distribution or political pressures. Our aim was to provide leaders with guidance on how to improve PSRA practice, by creating organizational contexts which enable high performance. We carried out in-depth case studies of six Canadian healthcare organizations to obtain from healthcare leaders their understanding of the concept of high performance in PSRA and the factors which contribute to its achievement. Individual and group interviews were carried out (n = 62) with senior managers, middle managers and Board members. Site observations and document review were used to assist researchers in interpreting the interview data. Qualitative data were analyzed iteratively with the literature on empirical examples of PSRA practice, in order to develop a framework of high performance in PSRA. The framework consists of four domains - structures, processes, attitudes and behaviours, and outcomes - within which are 19 specific elements. The emergent themes derive from case studies in different kinds of health organizations (urban/rural, small/large) across Canada. The elements can serve as a checklist for 'high performance' in PSRA. This framework provides a means by which decision-makers in healthcare might assess their practice and identify key areas for improvement. The findings are likely generalizable, certainly within Canada but also across countries. This work constitutes, to our knowledge, the first attempt to present a full package of elements comprising high performance in health care PSRA.

What constitutes high performance in priority setting and resource allocation? Decision maker narratives identified from a survey and qualitative study in Canadian healthcare organizations

Priority setting and resource allocation are key management functions; however, there may be different understandings as to what makes for a high-performing organization in this area. To interpret how decision makers actually approach this question, our research looks at what might contribute to one's reputation as such. Two sets of qualitative data are used. Senior healthcare leaders were asked to nominate organizations which they considered high performers in priority setting and resource allocation and to justify their choices. This open-ended question was analyzed to identify themes. Rigorous process was most often cited. Six case studies were subsequently conducted; respondents were asked to comment upon why they thought their organization might be named by others as a high performer. These replies were analyzed qualitatively to identify prominent storylines: three distinctive narratives are summarized here. These help us to understand how organization leaders in particular contexts bring together stakeholders to pursue locally appropriate strategies for achieving contextually defined high performance.

Using business intelligence to analyze and share health system infrastructure data in a rural health authority

Background

Health care organizations gather large volumes of data, which has been traditionally stored in legacy formats making it difficult to analyze or use effectively. Though recent government-funded initiatives have improved the situation, the quality of most existing data is poor, suffers from inconsistencies, and lacks integrity. Generating reports from such data is generally not considered feasible due to extensive labor, lack of reliability, and time constraints. Advanced data analytics is one way of extracting useful information from such data.

Objective

The intent of this study was to propose how Business Intelligence (BI) techniques can be applied to health system infrastructure data in order to make this information more accessible and comprehensible for a broader group of people.

Methods

An integration process was developed to cleanse and integrate data from disparate sources into a data warehouse. An Online Analytical Processing (OLAP) cube was then built to allow slicing along multiple dimensions determined by various key performance indicators (KPIs), representing population and patient profiles, case mix groups, and healthy community indicators. The use of mapping tools, customized shape files, and embedded objects further augment the navigation. Finally, Web forms provide a mechanism for remote uploading of data and transparent processing of the cube. For privileged information, access controls were implemented.

Results

Data visualization has eliminated tedious analysis through legacy reports and provided a mechanism for optimally aligning resources with needs. Stakeholders are able to visualize KPIs on a main dashboard, slice-and-dice data, generate ad hoc reports, and quickly find the desired information. In addition, comparison, availability, and service level reports can also be generated on demand. All reports can be drilled down for navigation at a finer granularity.

Conclusions

We have demonstrated how BI techniques and tools can be used in the health care environment to make informed decisions with reference to resource allocation and enhancement of the quality of patient care. The data can be uploaded immediately upon collection, thus keeping reports current. The modular design can be expanded to add new datasets such as for smoking rates, teen pregnancies, human immunodeficiency virus (HIV) rates, immunization coverage, and vital statistical summaries.

ECG machine QTc intervals are inaccurate in hemodialysis patients

BACKGROUND

Nephrologists need effective screening tools to identify hemodialysis patients at elevated risk for sudden cardiac death, the leading cause of death in this population. QTc intervals longer than 450 ms in males and 470 ms in females, measured by the gold standard tangent method (trueQTc), are prolonged and increase sudden cardiac death in healthy populations and patients with long QT syndrome.

METHODS

We performed a retrospective ECG and chart review of hemodialysis patients. Our first objective was to determine if machine-measured QTc intervals (macQTc) could be used to identify dialysis patients with prolonged trueQTc. Our second objective was to determine at what macQTc could prolonged trueQTc be confidently diagnosed.

RESULTS

macQTc differed from the trueQTc by an average of 16.54 ms, and by at least 20 ms in 46.8, 36.1, 53.6, 50.0 and 57.1% of all, short-hours daily hemodialysis, intermittent conventional hemodialysis, frequent nocturnal hemodialysis and intermittent nocturnal hemodialysis patients, respectively. The positive predictive value, negative predictive value, sensitivity and specificity of prolonged macQTc predicting prolonged trueQTc was 57.6, 92.6, 79.1 and 81.8%, respectively. Thus, macQTc is inaccurate at predicting the gold standard trueQTc in hemodialysis patients. macQTc greater than 480 ms in hemodialysis patients predicts trueQTc prolongation with a positive predictive value of 95.2%, but with a low sensitivity of 32.3%.

CONCLUSION

In hemodialysis patients, ECG macQTc intervals are insufficiently sensitive or specific to predict prolonged trueQTc intervals, unless >480 ms.

Decision maker perceptions of resource allocation processes in Canadian health care organizations: a national survey

BACKGROUND

Resource allocation is a key challenge for healthcare decision makers. While several case studies of organizational practice exist, there have been few large-scale cross-organization comparisons.

METHODS

Between January and April 2011, we conducted an on-line survey of senior decision makers within regional health authorities (and closely equivalent organizations) across all Canadian provinces and territories. We received returns from 92 individual managers, from 60 out of 89 organizations in total. The survey inquired about structures, process features, and behaviours related to organization-wide resource allocation decisions. We focus here on three main aspects: type of process, perceived fairness, and overall rating.

RESULTS

About one-half of respondents indicated that their organization used a formal process for resource allocation, while the others reported that political or historical factors were predominant. Seventy percent (70%) of respondents self-reported that their resource allocation process was fair and just over one-half assessed their process as 'good' or 'very good'. This paper explores these findings in greater detail and assesses them in context of the larger literature.

CONCLUSION

Data from this large-scale cross-jurisdictional survey helps to illustrate common challenges and areas of positive performance among Canada's health system leadership teams.

Pharmacokinetic profiles for oral and subcutaneous methotrexate in patients with Crohn's disease

BACKGROUND

Methotrexate (MTX) is administered subcutaneously to Crohn's Disease (CD) patients. There are very few studies evaluating the use of oral (PO) MTX in CD. A drug and its pharmaceutical alternative are equivalent (bioequivalence) when the bioavailability of the alternative falls within 80-125% of the bioavailability of the standard (US Food and Drug Administration - FDA).

AIM

To compare the pharmacokinetic (PK) profiles of PO and subcutaneous (SC) MTX in CD patients to determine the bioequivalence of these two routes.

METHODS

Eleven patients received a PO and an SC MTX dose (25 mg) separated by one week over a two-week interval. Blood samples were collected at specified times over a 24-h period for each patient on two separate days. MTX plasma levels were obtained using sensitive mass spectrometry. Areas under the curve (AUC) were compared between the two routes.

RESULTS

The mean AUC values were 3375 ng/mL × h (PO MTX) and 3985 ng/mL × h (SC MTX). The mean AUC ratio (PO/SC) was 0.86 (0.62-1.08). This correlates with a relative PO bioavailability of 86% in comparison to SC. The 90% confidence interval for the mean AUC (PO/SC) ratio is (0.785, 0.929). There were no adverse events.

CONCLUSIONS

The mean MTX AUC (PO/SC) in these patients falls outside the 90% confidence interval for the bioequivalence limit. SC MTX is more bioavailable than PO MTX; however, the mean relative MTX bioavailability (PO/SC) nearly met the FDA bioequivalence standard and PO MTX could be proposed in responders who would prefer this route.

Introducing priority setting and resource allocation in home and community care programs

OBJECTIVE

To use evidence from research to identify and implement priority setting and resource allocation that incorporates both ethical practices and economic principles.

METHOD

Program budgeting and marginal analysis (PBMA) is based on two key economic principles: opportunity cost (i.e. doing one thing instead of another) and the margin (i.e. resource allocation should result in maximum benefit for available resources). An ethical framework for priority setting and resource allocation known as Accountability for Reasonableness (A4R) focuses on making sure that resource allocations are based on a fair decision-making process. It includes the following four conditions: publicity; relevance; appeals; and enforcement. More recent literature on the topic suggests that a fifth condition, that of empowerment, should be added to the Framework. The 2007-08 operating budget for Home and Community Care, excluding the residential sector, was developed using PBMA and incorporating the A4R conditions.

RESULTS

Recommendations developed using PBMA were forwarded to the Executive Committee, approved and implemented for the 2007-08 fiscal year operating budget. In addition there were two projects approved for approximately $200,000.

CONCLUSION

PBMA is an improvement over previous practice. Managers of Home and Community Care are committed to using the process for the 2008-09 fiscal year operating budget and expanding its use to include mental health and addictions services. In addition, managers of public health prevention and promotion services are considering using the process.

Troponin I as a diagnostic marker of a perioperative myocardial infarction in the orthopedic population

STUDY OBJECTIVE

To assess the utility of troponin I, the only molecular marker of myocardial injury not expressed in regenerating muscle, in diagnosing perioperative myocardial infarction (MI) in the setting of orthopedic surgery where false elevations in creatine kinase MB isoenzymes (CKMB) are known to occur.

DESIGN

Prospective study.

SETTING

University-affiliated hospital.

PATIENTS

85 patients with risk factors for coronary artery disease (CAD) who were scheduled for orthopedic surgery, including total knee arthroplasty, 34; total hip arthroplasty, 36; posterior spine fusion, 7; and other orthopedic operations, 8.

INTERVENTIONS

Patients were observed in the postanesthesia care unit for at least 24 hours where they had an electrocardiogram (ECG) performed, and blood drawn to rule out MI.

MEASUREMENTS

Blood samples for measurement of creatine kinase MB isoenzymes (CKMB) and troponin I were drawn at 8-hour intervals for up to 24 hours.

MAIN RESULTS

Five (5/85) patients had elevated levels of both CKMB and troponin I postoperatively. New ECG abnormalities were present in all but one patient who had an old anterolateral MI. Troponin I peaked within 16 hours except in one patient where it continued to increase. That female patient developed cardiogenic pulmonary edema. All the others did well clinically. Six patients (6/85) had a positive CKMB index, and a negative troponin I level. None had ECG changes, except for one in whom subsequent cardiac catheterization showed insignificant CAD. They all did well clinically. All patients with an elevated troponin I level had a positive CKMB index.

CONCLUSIONS

Troponin I is as sensitive a marker of MI as CKMB in the orthopedic population, but it has a higher specificity in the perioperative setting. Troponin I can be helpful in properly identifying the source of CKMB elevation postoperatively when this elevation is questionable.

The efficacy of antifibrinolytics in the reduction of blood loss during complex adult reconstructive spine surgery

STUDY DESIGN

Controlled study to assess the efficacy of aprotinin and Amicar in reducing blood loss during complex spinal fusions.

OBJECTIVES

To compare blood loss and the clotting profile with a thromboelastogram in patients with spinal deformities undergoing sequential anterior and posterior spinal fusions treated intraoperatively with either aprotinin or Amicar.

SUMMARY OF BACKGROUND DATA

Spinal fusion for correction of adult spinal deformities is associated with large blood losses despite the implementation of multiple factors to reduce this blood loss. The antifibrinolytics aprotinin and Amicar have both been shown to reduce blood loss in other surgical procedures with the potential for large blood loss. Hence, we compared their efficacy for reducing blood loss in complex spinal fusions.

METHODS

Sixty patients for elective sequential anteroposterior thoracolumbosacral fusions were randomly assigned to three groups: control, aprotinin, and Amicar. Patients were assessed for blood loss, transfusion requirements, postoperative complications, and coagulation profile using a thromboelastogram.

RESULTS

The study demonstrated a significant reduction in total blood loss (aprotinin 3628 mL, Amicar 4056 mL, control 5181 mL) and transfusion requirements using the half-dose aprotinin regimen compared with Amicar or control. Aprotinin also preserved the thromboelastogram mean clot formation time, clot strength, and clotting index compared with Amicar or control.

CONCLUSIONS

For complex spinal operations with large blood losses, the half-dose aprotinin regimen will reduce blood loss and the need for blood components and may have a role in reducing postoperative lung injury.

Evidence of lung injury during reconstructive surgery for adult spinal deformities with pulmonary artery pressure monitoring

STUDY DESIGN

Observational analyses of 55 adult patients who underwent elective sequential anterior-posterior thoracolumbosacral surgical corrections for spinal deformities were used to evaluate the efficacy of pulmonary artery catheter monitoring.

OBJECTIVE

To demonstrate that during complex reconstructive surgery for spinal deformities, pulmonary artery catheter monitoring identifies a subset of patients with pulmonary injury and is essential in their management.

SUMMARY OF BACKGROUND DATA

Patients who undergo sequential anterior-posterior thoracolumbosacral surgical corrections for spinal deformities experience significant perioperative morbidity. Although the value of pulmonary artery catheter monitoring is controversial, its use in these procedures may help identify potential physiologic complications and improve surgical outcome.

METHODS

All patients were monitored with a pulmonary artery catheter during surgery until at least postoperative day 1. Outcome measurements included blood loss, vertebral levels fused, operative time, postoperative respiratory complications, and days in intensive care.

RESULTS

Eight (8/55; 14.5%) patients according to pulmonary artery catheter monitoring demonstrated elevated pulmonary vascular resistance and noncardiac pulmonary edema. These patients had longer operative procedures with greater blood loss and had more postoperative respiratory complications. They were treated appropriately in intensive care and discharged without further complications.

CONCLUSION

Pulmonary artery catheter monitoring of patients who undergo complex spinal fusion facilitates the identification of patients with pulmonary injury and is essential in the management of these patients in the postoperative period. It may, also, be a marker for embolic injury to the lung.

Effect of epidural analgesia on venous blood flow after hip arthroplasty

The effects of postoperative epidural infusions using local anesthetic and narcotic were assessed in reference to lower extremity blood flow. Nineteen patients who underwent unilateral total hip arthroplasty were randomly assigned to receive a postoperative epidural infusion of either 5 microg/ml fentanyl or 5 microg/ml fentanyl plus 0.125% bupivacaine at a rate of 10 ml per hour. The infusions were started after complete resolution of the operative epidural blockade. Femoral venous blood flow volume and velocity were measured above and below the saphenous vein bifurcation using an Acuson #128XP/10 computed sonography system (duplex ultrasound) and proprietary software. Femoral venous blood flow was not affected by the type of infusion and did not increase during the study period. However, femoral venous blood flow volume increased 50% after active flexion and extension of the foot, 10 times in quick succession. The addition of bupivacaine (a local anesthetic that blocks sympathetic afferent nerves) to a postoperative epidural infusion does not augment blood flow from the deep veins of the leg after total hip arthroplasty. Alternatively, lower extremity skeletal muscle activity significantly enhances femoral venous blood flow and may be a useful adjunct in deep venous thrombosis prevention.

Evaluation of brachial plexus anesthesia for upper extremity surgery

BACKGROUND AND OBJECTIVES

Brachial plexus anesthesia is the preferred anesthetic at the authors' institution for upper extremity surgery. The article is a prospective observational evaluation of brachial plexus anesthesia for surgical success of the block and immediate and postoperative complications.

METHODS

Patients for upper extremity surgery (n = 508) received either an interscalene block (n = 266) or an axillary block (n = 242). Surgical anesthesia was achieved in 97% of the patients receiving an interscalene block and 93% receiving an axillary block.

RESULTS

For the interscalene block, a proximal paresthesia (shoulder) was as reliable as a more distal paresthesia (forearm, hand) for shoulder surgery. For performance of the axillary block, the transarterial approach was more successful than a single paresthesia for surgical anesthesia (96% versus 80%). Major immediate complications were infrequent, with only one mild seizure in the axillary block group and evidence of intravascular injection in only two of the patients in the interscalene block group. Many of the patients had mild paresthesias on the first day after the operation, 9% for the interscalene block and 19% for the axillary block. The incidence of postoperative neuropraxias decreased significantly by 2 weeks (interscalene block 3%, axillary block 5%), with only one patient in each group still experiencing symptoms beyond 4 weeks. In the interscalene block group, postoperative neuropraxias were associated with the site of paresthesia used for performance of the block and the use of bupivacaine.

CONCLUSION

Both interscalene and axillary blocks are safe and effective techniques for upper extremity surgery.

Supraventricular tachyarrhythmias during total joint arthroplasty. Incidence and risk

Perioperative supraventricular tachyarrhythmias (AF/SVT) have been long recognized as a complication after major surgery, but little is known about the incidence after major nonthoracic surgery. One thousand two hundred ten consecutive patients undergoing total hip or knee arthroplasty were studied to determine the incidence of new onset AF/SVT. Information on preoperative medical history and laboratory tests were collected in a subset of 583 patients, and analyzed using logistic regression and linear analysis to determine risk. Ninety-four-and-one-half percent of patients received an epidural anesthetic, 4.1% had general anesthesia and 1.3% had spinal anesthesia. New onset AF/SVT was found in 38 of 1210 patients, representing an incidence of 3.1%. In the subset of 583 patients, the incidence was 4.8%. The only variables found to be independently associated with the perioperative development of AF/SVT were a history of atrial fibrillation, increasing age, left anterior hemi-block, and atrial premature depolarizations on the preoperative electrocardiogram. In those patients 60 years of age or older with one or more positive risk factors (13% of the study population), the incidence was 18.2%. In those patients less than 60 years of age with none of the identified risks, the incidence was 1.9%.

The effect of two levels of hypotension on intraoperative blood loss during total hip arthroplasty performed under lumbar epidural anesthesia

The degree of induced hypotension necessary to achieve a significant reduction in intraoperative blood loss has never been defined. Forty patients undergoing primary total hip arthroplasty during epidural anesthesia by a single surgeon were randomly assigned to have mean arterial pressure maintained at 50 +/- 5 mm Hg or 60 +/- 5 mm Hg throughout surgery. Intraoperative blood loss was 179 +/- 73 mL in the 50 mm Hg group and 263 +/- 98 mL in the 60 mm Hg group (P = 0.004). Subjectively, there was more bleeding during surgery in the 60 mm Hg group during dissection of the hip joint (P = 0.0026) and while reaming the acetabulum (P = 0.0001) and femur (P = 0.0001). No difference in transfusion requirements, postoperative hematocrit, or duration of surgery was noted. A difference in mean arterial blood pressure of 10 mm Hg from 50 to 60 mm Hg during surgery for total hip arthroplasty under epidural anesthesia has a measurable effect on intraoperative blood loss.

Factors influencing deep vein thrombosis following total hip arthroplasty under epidural anesthesia

To determine intraoperative factors which may influence deep vein thrombosis rate, we studied surgeries performed by one surgeon on 441 consecutive patients undergoing primary total hip arthroplasty under epidural anesthesia. Operative limb venography was performed on the fourth or fifth postoperative day in 381 patients, who received 650 mg of aspirin daily as the only postoperative thromboprophylaxis. Of 381 (15%) patients, 58 had a positive venogram; 13 (3%) had proximal thrombi. Of 178 patients (9.5%) with surgery lasting less than 70 min, 17 developed deep vein thrombosis whereas 41 of 203 patients (20.3%) with surgery lasting more than 70 min developed deep vein thrombosis (P < 0.05). Corresponding proximal deep vein thrombosis rates increased from 1.7% to 4.9%. Deep vein thrombosis was observed in 12.5% of patients receiving intravenous low-dose epinephrine, 10.3% receiving intravenous sodium nitroprusside, 14.5% receiving both low-dose epinephrine and sodium nitroprusside concurrently, and 25% receiving intravenous fluid alone. Proximal deep vein thrombosis rates were 2.4%, 0%, 1.45%, and 9.3% in these groups, respectively. These data suggest that the intraoperative management of both surgery and anesthesia influence rates of deep vein thrombosis following total hip arthroplasty.

Factors affecting deep vein thrombosis rate following total knee arthroplasty under epidural anesthesia

A retrospective review was performed of 448 consecutive patients undergoing primary, unilateral, bicondylar, and cemented total knee arthroplasty under epidural anesthesia by three surgeons to determine factors contributing to deep vein thrombosis rate. All had venography on the fourth or fifth postoperative day and received aspirin and elastic stockings as their only thromboprophylaxis. The overall deep vein thrombosis rate was 41% (2% had proximal clots). The rate of deep vein thrombosis was not related to obesity, history of heart disease, hypertension, prior malignancy, smoking, diagnosis of osteoarthritis, duration of surgery, type of local anesthetic used, or the use of postoperative epidural analgesia. The rate of deep vein thrombosis varied significantly between surgeons: one surgeon had an overall deep vein thrombosis rate of 58% (proximal thrombi, 4%) whereas the other two surgeons had a deep vein thrombosis rate of 35% (proximal clot thrombi, 1%). A number of possible mechanisms to explain the variation in deep vein thrombosis rates between surgeons are provided.

The effect of two levels of hypotension on intraoperative blood loss during total hip arthroplasty performed under lumbar epidural anesthesia

The degree of induced hypotension necessary to achieve a significant reduction in intraoperative blood loss has never been defined. Forty patients undergoing primary total hip arthroplasty during epidural anesthesia by a single surgeon were randomly assigned to have mean arterial pressure maintained at 50 +/- 5 mm Hg or 60 +/- 5 mm Hg throughout surgery. Intraoperative blood loss was 179 +/- 73 mL in the 50 mm Hg group and 263 +/- 98 mL in the 60 mm Hg group (P = 0.004). Subjectively, there was more bleeding during surgery in the 60 mm Hg group during dissection of the hip joint (P = 0.0026) and while reaming the acetabulum (P = 0.0001) and femur (P = 0.0001). No difference in transfusion requirements, postoperative hematocrit, or duration of surgery was noted. A difference in mean arterial blood pressure of 10 mm Hg from 50 to 60 mm Hg during surgery for total hip arthroplasty under epidural anesthesia has a measurable effect on intraoperative blood loss.

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.

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.

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.

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.

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.

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).

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.

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.