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V A Lawrence

Publications and source records attributed to V A Lawrence.

At least 19 recordsLinked to original sources
PubMed1998

Perioperative blood transfusion and postoperative mortality.

CONTEXT: The risks of blood transfusion have been studied extensively but the benefits and the hemoglobin concentration at which patients should receive a transfusion have not. OBJECTIVE: To determine the effect of perioperative transfusion on 30- and 90-day postoperative mortality. DESIGN: Retrospective cohort study. SETTING: A total of 20 US hospitals between 1983 and 1993. PARTICIPANTS: A total of 8787 consecutive hip fracture patients, aged 60 years or older, who underwent surgical repair. MAIN OUTCOME MEASURES: Primary outcome was 30-day postoperative mortality; secondary outcome was 90-day postoperative mortality. The "trigger" hemoglobin level was defined as the lowest hemoglobin level prior to the first transfusion during the time period or, for patients in the nontranfused group, as the lowest hemoglobin level during the time period. RESULTS: Overall 30-day mortality was 4.6% (n=402; 95% confidence interval [CI], 4.1%-5.0%); overall 90-day mortality was 9.0% (n=788; 95% CI, 8.4%-9.6%). A total of 42% of patients (n=3699) received a postoperative transfusion. Among patients with trigger hemoglobin levels between 80 and 100 g/L (8.0 and 10.0 g/dL), 55.6% received a transfusion, while 90.5% of patients with hemoglobin levels less than 80 g/L (8.0 g/dL) received postoperative transfusions. Postoperative transfusion did not influence 30- or 90-day mortality after adjusting for trigger hemoglobin level, cardiovascular disease, and other risk factors for death: for 30-day mortality, the adjusted odds ratio (OR) was 0.96 (95% CI, 0.74-1.26); for 90-day mortality, the adjusted hazard ratio was 1.08 (95% CI, 0.90-1.29). Similarly, 30-day mortality after surgery did not differ between those who received a preoperative transfusion and those who did not (adjusted OR, 1.23; 95% CI, 0.81-1.89). CONCLUSIONS: Perioperative transfusion in patients with hemoglobin levels 80 g/L (8.0 g/dL) or higher did not appear to influence the risk of 30- or 90-day mortality in this elderly population. At hemoglobin concentrations of less than 80 g/L (8.0 g/dL), 90.5% of patients received a transfusion, precluding further analysis of the association of transfusion and mortality.

Aged↗
PubMed1997

Preoperative spirometry and laparotomy: blowing away dollars.

STUDY OBJECTIVE: Increasing evidence indicates that routine preoperative diagnostic spirometry (pulmonary function tests [PFTs]) before elective abdominal surgery does not predict individual risk of postoperative pulmonary complications and is overutilized. This economic evaluation estimates potential savings from reduced use of preoperative PFTs. DESIGN: Analyses of (1) real costs (resource consumption to perform tests) and (2) reimbursements (expenditures for charges) by third-party payers. SETTING: University-affiliated public and Veterans Affairs hospitals. PATIENTS: Adults undergoing elective abdominal operations. MEASUREMENTS AND RESULTS: Average real cost of PFTs was $19.07 (95% confidence interval [CI], $18.53 to $19.61), based on a time and motion study. Average reimbursement expenditure by third-party payers for PFTs was $85 (range, $33 to $150; 95% CI, $68 to $103), based on Medicare payment of $52 and a survey of nine urban US hospitals with a spectrum of bed sizes and teaching status. Estimates from published literature included the following: (1) annual number of major abdominal operations, 3.5 million; and (2) proportion of PFTs not meeting current guidelines, 39% (95% CI, 0.31 to 0.47). Local data were used when estimates were not available in the literature: (1) proportion of laparotomies that are elective, 76% (95% CI, 0.73 to 0.79); and (2) frequency of PFTs before laparotomy, 69% (95% CI, 0.54 to 0.84). Estimated annual national real costs for preoperative PFTs are $25 million to $45 million. If use of PFTs were reduced by our estimate for the proportion of PFTs not meeting current guidelines, potential annual national cost savings would be $7,925,411 to $21,406,707. National reimbursement expenditures by third-party payers range from more than $90 million to more than $235 million. If use were reduced, potential annual savings in reimbursements would be $29,084,076 to $111,345,440. Potential savings to Medicare approach $8 million to $20 million annually. CONCLUSION: Reduced use of PFTs before elective abdominal surgery could generate substantial savings. Current evidence indicates reduced use would not compromise patients' outcomes.

Abdomen↗
PubMed1996

Appendicitis: higher risk in Mexican Americans?

OBJECTIVES: Mexican Americans (MAs), compared to white non-Hispanics (WNHs), have higher rates of biliary disease, noninsulin dependent diabetes, and endstage renal disease but lower rates of lung cancer, hip fractures, and mortality from coronary heart disease. Relatively little research has been done to identify other ethnic differences in disease incidence. We used surgical procedure rates to confirm known ethnic differences and to explore our clinical suspicion that MAs have higher rates of appendectomy than WNHs. METHODS: We used a registry of surgical procedures at two teaching hospitals in South Texas to calculate proportional operation ratios (PORs) for MAs versus WNHs. These two hospitals are the primary source of acute hospital care for the indigent in the area. The POR is arithmetically identical to proportional incidence and mortality ratios. RESULTS: MAs underwent appendectomy proportionally more often than WNHs at both hospitals (POR = 1.41 and 1.75, p < 0.0001). Other significant PORs were consistent with known ethnic disease differences in biliary tract operations, vascular access for chronic hemodialysis, lung cancer, and coronary artery bypass. CONCLUSIONS: These findings support the hypothesis that MAs may undergo appendectomy more often than WNHs and so may be at higher risk of appendicitis.

Adolescent↗
PubMed1996

Risk of pulmonary complications after elective abdominal surgery.

STUDY OBJECTIVE: Intra-abdominal operations are relatively high risk for pulmonary complications. Previous research has more intensely investigated cardiac operative risk, but recent work suggests that significant pulmonary complications may be more common than cardiac complications and associated with longer length of stay. This study identified risk indicators for pulmonary complications after elective abdominal operations. DESIGN: Nested case-control. SETTING: University affiliated Veterans Affairs hospital. PATIENTS: We used a computerized registry of all 2,291 patients undergoing elective abdominal operations from 1982 to 1991. Ascertainment and verification of pulmonary and cardiac complications were systematic and explicit. Charts of all 116 patients identified by the registry as having complications and 412 (19%) randomly selected from 2,175 remaining patients were reviewed to verify complications, using explicit criteria and independent abstraction of preoperative and postoperative components of charts. From 528 validated subjects (23% of the cohort), 82 cases and 82 control subjects were closely matched by operation type and age, +/- 10 years. MEASUREMENTS AND RESULTS: The primary outcome measure was postoperative pulmonary complications. Among 82 cases with pulmonary complications, 27 (33%) also had cardiac complications. Preoperative variables independently associated with pulmonary complications by multivariable analysis (p < or = 0.05) included the following: Charlson comorbidity index (per point odds ratio [OR], 1.6; 95% confidence interval [CI], 1.004 to 2.6), Goldman cardiac risk index (per point OR, 2.04; 95% CI, 1.17 to 3.6), abnormal chest radiograph (OR, 3.2; 95% CI, 1.07 to 9.4), and abnormal findings on lung examination (OR, 5.8; 95% CI, 1.04 to 32). Equal proportions of cases and control subjects had preoperative diagnostic spirometry. No component of spirometry predicted complications, including severity of obstructive lung disease. CONCLUSIONS: For pulmonary operative risk, abnormal results of lung examination and chest radiography plus cardiac and overall comorbidity were important. Spirometry was not helpful. Because 33% of cases had both cardiac and pulmonary complications, future studies should prospectively examine comparative incidence, outcomes, and predictors of both type of complications.

Abdomen↗
PubMed1996

Where does it hurt? Stability of recordings of pain location using the McGill Pain Map.

OBJECTIVE: To evaluate the validity and reliability of recordings of pain location among patients with pain from 2 different sources, using the McGill Pain Map (MPM). METHODS: Consecutive outpatients from a rheumatology clinic and inpatients recovering from surgical interventions participated in a structured interview during which the McGill Pain Questionnaire and the MPM were administered. After an interval of 3 to 6 weeks for the rheumatology patients and 1 to 2 days for the postoperative patients, a 2nd identical interview was administered. Criterion related validity was examined by testing whether the extent [total number of painful areas (NPA)] and distribution (individual body areas affected) of pain differed significantly between the 2 patient groups and whether, among postoperative patients, the distribution of pain was consistent with the site of surgical incision. Test-retest reliability of the recordings on the MPM was measured by calculating a kappa coefficient for each individual body area on the MPM, and an intraclass correlation coefficient for the NPA. RESULTS: 51 rheumatology and 47 postoperative patients were interviewed. Significant differences in the total NPA (4.1 +/- 3.0 vs 11.5 +/- 6.2; p < 0.001) and in the distribution of the painful areas were observed between the 2 groups. Among postoperative patients, there was no significant difference in the NPA between the 2 interviews (4.1 +/- 3.0 vs 4.3 +/- 3.5; p = 0.53), while among rheumatology patients, there was a reduction in the NPA at the second interview (11.5 +/- 6.2 vs 9.8 +/- 5.3; p = 0.007). Reliability of the recordings of pain location by individual areas averaged 0.50 (range 0.04 to 0.76). The reliability of the NPA was 0.82 for the combined group of patients (0.71 and 0.84, respectively). CONCLUSION: Recordings of pain location using the MPM are valid and reliable. The MPM is a valuable instrument for studies of the distribution of pain in populations.

Adult↗
PubMed1995

Incidence and hospital stay for cardiac and pulmonary complications after abdominal surgery.

OBJECTIVE: Internists frequently evaluate preoperative cardiopulmonary risk and co-manage cardiac and pulmonary complications, but the comparative incidence and clinical importance of these complications are not clearly delineated. This study evaluated incidence and length of stay for both cardiac and pulmonary complications after elective laparotomy. DESIGN: Nested case-control. SETTING: University-affiliated Department of Veterans Affairs Hospital. PATIENTS: Computerized registry of all 2,291 patients undergoing elective abdominal operations from 1982 to 1991. MEASUREMENT AND MAIN RESULTS: Strategy for ascertainment and verification of complications was systematic and explicit. The charts of all 116 patients identified by the registry as having complications and 412 (19%) randomly selected from 2,175 remaining patients were reviewed to verify presence or absence of cardiac or pulmonary complications, using explicit criteria and independent abstraction of pre- and postoperative components of charts. From these 528 validated cases and controls (23% of the cohort), 96 cases and 96 controls were matched by operation type and age within ten years. Hospital and intensive care unit stays were significantly longer (p < 0.0001) for the cases than for the controls (24.1 vs 10.3 and 5.6 vs 1.5 days, respectively). All 19 deaths occurred among the cases. Among the cases, pulmonary complications occurred significantly more often than cardiac complications (p < 0.00001) and were associated with significantly longer hospital stays (22.7 vs 10.4 days, p = 0.001). Combined cardiopulmonary complications occurred among 28% of the cases. Misclassification-corrected incidence rates for the entire cohort were 9.6% (95% CI 7.2-12.0) for pulmonary and 5.7% (95% CI 3.6-7.7) for cardiac complications. CONCLUSIONS: For noncardiac surgery, previous research has focused on cardiac risk. In this study, pulmonary complications were more frequent, were associated with longer hospital stay, and occurred in combination with cardiac complications in a substantial proportion of cases. These results suggest that further research is needed to fully characterize the clinical epidemiology of postoperative cardiac and pulmonary complications and better guide preoperative risk assessment.

Abdomen↗
PubMed1994

Anesthesia.

Explore the source record for details and available documents.

Anesthesia↗
PubMed1994

The relationship between disease and function and perceived health in very frail elders.

OBJECTIVE: To study associations between disease and observed function and self-perceived health in very frail elders. DESIGN AND SETTING: Cross-sectional survey of nine nursing homes in San Antonio, TX. PARTICIPANTS: 194 elderly long-stay nursing home residents dependent in at least two ADLs and without severe cognitive impairment. MEASURES: Burden of disease (BOD) was chart abstracted using a standardized protocol that assessed types and severities of 59 categorizations of chronic and acute medical conditions. Observed function and self-perceived health status were assessed independently by the Katz Activities of Daily Living scale (ADL) and the Sickness Impact Profile (SIP), respectively. RESULTS: Summary BOD scores had a low, but statistically significant, univariate correlation with ADL scores (r = 0.21, P = 0.003) and no significant correlation with SIP scores (R = -0.008). Multiple linear regression analyses, including the 24 most frequent disease categories, showed that disease explained significant amounts of ADL (r2 = 0.25, P = 0.001) and borderline significant amounts of SIP (r2 = 0.16, P = 0.11). Models including both disease and sociodemographic, cognitive, and affective variables showed disease added significant incremental explantation beyond the other factors to ADL (incremental r2 = 0.14, P = 0.04), but not to SIP (incremental r2 = 0.08, P > 0.10). CONCLUSIONS: Disease, observed function, and self-perceived health status are separate, but interrelated entities, with disease having a stronger relationship to observed function than self-perceived health. Comprehensive assessment of frail elders may need to include all three areas, and studies that focus on one area should take into account the other two as potential important covariates.

Activities of Daily Living↗
PubMed1993

Preoperative HIV testing: is it less expensive than universal precautions?

Universal precautions are officially recommended to prevent HIV transmission in health care settings but for elective surgery some advocate routine preoperative HIV testing. These strategies have not been tested in clinical trials but universal precautions are very expensive and not cost-effective. Thus, for elective surgery, routine testing might save resources by permitting selective use of additional barrier precautions. We performed an economic evaluation to compare both strategies, using a simple approach to determine if routine testing (RT) is less expensive than universal precautions (UP). Conservatively assuming equal effectiveness in preventing HIV transmission, we compared a minimized estimate for the average cost of RT with a maximized estimate for the average cost of UP per elective operation. The minimized estimate for RT (US$57) was greater than the maximized estimate for UP (US$36) per procedure. Results were stable or strengthened by sensitivity analysis. Routine HIV testing is not a valid economic alternative to UP for elective surgery. The simple methodology used in this study can be a preliminary strategy to review other strategies for preventing HIV transmission. This method is particularly useful when data are inadequate for a formal economic evaluation to determine the utility of collecting the detailed information necessary for a full comparison.

Blotting, Western↗
PubMed1993

Postoperative complications after thoracic and major abdominal surgery in patients with and without obstructive lung disease.

STUDY OBJECTIVE: To determine the risk of thoracic and major abdominal surgery in patients with chronic obstructive pulmonary disease (COPD). DESIGN: Retrospective cohort study with controls. SETTING: A 692-bed teaching hospital. PATIENTS: A cohort of 26 patients with severe COPD (FEV1 < 50 percent predicted) undergoing thoracic and major abdominal surgery was matched by age and type of operation to 52 patients with mild-moderate COPD and 52 patients with no COPD. MEASUREMENTS AND RESULTS: The 26 patients with severe COPD had rates of cardiac, vascular, and minor pulmonary complications similar to patients with mild-moderate COPD and without COPD, but experienced higher rates of serious pulmonary complications (23 percent vs 10 percent vs 4 percent, p = 0.03) and death (19 percent vs 4 percent vs 2 percent, p = 0.02). All deaths and instances of ventilatory failure in the patients with severe COPD occurred in the subset undergoing coronary artery bypass surgery. Logistic regression revealed that increased age, higher American Society of Anesthesiologists class, an abnormal chest radiograph, and perioperative bronchodilator administration were associated with higher cardiac or serious pulmonary complication rates. Spirometry was not an independent predictor of postoperative complications. CONCLUSIONS: Clinical variables appear better than preoperative spirometry in predicting postoperative cardiopulmonary complications. The utility of preoperative spirometry as well as the benefits of perioperative bronchodilators in patients in stable condition remain to be determined.

Abdomen↗
PubMed1992

Acute low back pain and economics of therapy: the iterative loop approach.

We use the measurement iterative loop as a conceptual framework to examine the economics of common therapies for acute non-specific low back pain. The measurement iterative loop systematically assesses the interlocking facets of an illness from the community health perspective, including quantifying burden of illness, etiology, assessment of therapeutic effectiveness, and economic evaluation of therapies. The iterative loop reveals that: (1) burden of illness, although known to be substantial, is so far inaccurately measured, (2) little is known about such factors as provider and patient compliance; and (3) the economics of therapy can guide us in this time of clinical uncertainty when no therapy appears clearly superior. For therapies with at least some support from randomized controlled trials, bedrest appears to be economically superior. Besides burden of illness, compliance, and current therapies, future research should address such "therapeutic" options as early return to work and patient self-management.

Acute Disease↗
PubMed1992

Operative risk in patients with severe obstructive pulmonary disease.

BACKGROUND: We wanted to determine the risk of postoperative pulmonary complications and mortality in patients with severe chronic obstructive pulmonary disease. METHODS: We reviewed 107 consecutive operations performed in 89 patients with severe chronic obstructive pulmonary disease (forced expiratory volume in 1 second, less than 50% of predicted). RESULTS: Postoperative pulmonary complications occurred in 31 operations (29%) and were significantly related to the type and duration of surgery. Also, American Society of Anesthesiologists class approached significance as a predictor. Postoperative pulmonary complications occurred at higher rates in coronary artery bypass grafting and major abdominal procedures (60% and 56%) than in other operations involving general or spinal anesthesia (27%) or in procedures performed with the patient under regional or local anesthesia (16%). When the durations of the operations were classified as less than 1 hour, 1 to 2 hours, 2 to 4 hours, and more than 4 hours, the rates of postoperative pulmonary complications were 4%, 23%, 38%, and 73%, respectively. Regarding American Society of Anesthesiologists class, postoperative pulmonary complications occurred in 10% of patients in class II, 28% of those in class III, and 46% of those in class IV. In terms of life-threatening complications, there were six deaths and only two cases of nonfatal ventilatory failure. Notably, mortality clustered primarily in coronary artery bypass graft procedures. Five of 10 patients receiving coronary artery bypass grafts died, compared with one death after 97 non-coronary artery bypass graft operations (50% vs 1%). CONCLUSIONS: Although the risk of coronary artery bypass grafting deserves further study, noncardiac surgery carries an acceptable operative risk in patients with severe chronic obstructive pulmonary disease.

Aged↗
PubMed1989

The unproven utility of the preoperative urinalysis: economic evaluation.

The clinical effectiveness of the preoperative urinalysis is unproven, yet it is routinely obtained before surgery. To determine if the routine urinalysis might be economically beneficial, we evaluated its cost-effectiveness and cost-benefit. In the setting of elective clean-wound, non-prosthetic knee procedures, we estimated that: (1) nearly U.S. $7,000,000 is spent annually on preoperative urinalyses and associated costs; (2) given the best estimate of the increase in risk of wound infection attributable to urinary tract infection, 4.58 wound infections may be prevented annually, at a cost of $1,500,000 per wound infection prevented; (3) the cost of treating additional cases of wound infection, given no preoperative urinalysis, is approximately five hundred-fold less than the cost of screening with routine urinalyses. We conclude that the routine preoperative urinalysis is clinically and economically unsound before clean-wound, non-prosthetic knee surgery and probably before other types of clean-wound surgery. For this relatively inexpensive test, aggregate costs are disproportionately high and appear to outweight clinical benefits.

Aged↗
PubMed1989

Preoperative spirometry before abdominal operations. A critical appraisal of its predictive value.

Preoperative spirometry is commonly ordered before abdominal surgery, with the goal of predicting and preventing postoperative pulmonary complications. We assessed the evidence for this practice with a systematic literature search and critical appraisal of published studies. The search identified 135 clinical articles, of which 22 (16%) were actual investigations of the use and predictive value of preoperative spirometry. All 22 studies had important methodological flaws that preclude valid conclusions about the value of screening preoperative spirometry. The available evidence indicates that spirometry's predictive value is unproved. Unanswered questions involve (1) the yield of spirometry, in addition to history and physical examination, in patients with clinically apparent lung disease; (2) spirometry's yield in detecting surgically important occult disease; and (3) its utility, or beneficial effect on patient outcome. Spirometry's full potential for risk assessment in the individual patient has not yet been realized.

Abdomen↗
PubMed1988

The unproven utility of preoperative urinalysis. Clinical use.

We investigated the utility, ie, relevance to clinical outcome, of routine preoperative urinalysis with a retrospective study of 200 clean-wound, orthopedic, nonprosthetic knee procedures. Physicians primarily order a preoperative urinalysis to detect infection, because of the purported relationship between remote infection and surgical wound infection. We found that preoperative urinalysis is uniformly ordered, with a high prevalence of abnormal results (15%) but a low physician-response rate (29%). Wound infection was rare, but there was no difference in frequency of wound infection between patients with normal and abnormal results of urinalysis. We conclude that the utility of routine preoperative urinalysis is unproven. Current practice does not agree with the rationale for ordering this test, nor does published literature support it. Although data are inadequate to fully define the appropriate use of preoperative urinalysis, we suggest clinical recommendations and avenues for further research.

Adult↗
PubMed1987

Cancer and resuscitation. Does the diagnosis affect the decision?

We asked if physicians are less likely to resuscitate patients with cancer because of the diagnostic label alone. We composed a questionnaire of nine patient vignettes with similar expected mortality rates, identical quality of life, and witnessed cardiopulmonary arrest. Internists and neurologists in a university training program were asked to decide, for each "patient," whether to administer cardiopulmonary resuscitation (CPR) before and after being informed of similar mortality rates. Decisions for CPR were less frequent for cancer vignettes than for vignettes of other chronic medical illnesses before and after mortality information was given. Analysis indicated that decisions varied among physicians according to their subspecialties. Overall, women favored resuscitation less often than did men. The diagnosis of cancer appears to have a negative impact on physicians' CPR decisions over and above that due to inaccurate prognostic assumptions about cancer. A physician's subspecialty and gender may also influence resuscitation decisions for patients in general.

Aged↗