Creating a model to predict time intervals from induction of labor to induction of anesthesia and delivery to coordinate workload.

BACKGROUND: Induction of labor continues to become more common. We analyzed induction of labor and timing of obstetric and anesthesia work to create a model to predict the induction-anesthesia interval and the induction-delivery interval in order to co-ordinate workload to occur when staff are most available. METHODS: Patients who underwent induction of labor at a single medical center were identified and multivariable linear regression was used to model anesthesia and delivery times. Data were collected on date of birth, race/ethnicity, body mass index, gestational age, gravidity, parity, indication for labor induction, number of prior deliveries, time of induction, induction agent, cervical dilation, effacement, and fetal station on admission, date and time of anesthesia administration, date and time of delivery, and delivery type. RESULTS: A total of 1746 women met inclusion criteria. Associations which significantly influenced time from induction of labor to anesthesia and delivery included maternal age (anesthesia P <0.001, delivery P =0.002), body mass index (both P <0.001), prior vaginal delivery (both P <0.001), gestational age (anesthesia P <0.001, delivery P <0.018), simplified Bishop score (both P <0.001), and first induction agent (both P <0.001). Induction of labor of nulliparous women at 02:00 h and parous women at 04:00 or 05:00 h had the highest estimated probability of the mother having her first anesthesia encounter and delivering during optimally staffed hours when our institution's specialty personnel are most available. CONCLUSIONS: Time to obstetric and anesthesia tasks can be estimated to optimize induction of labor start times, and shift anesthesia and delivery workload to hours when staff are most available.

Contrast-induced nephropathy: the wheel has turned 360 degrees.

Contrast-induced nephropathy (CIN) has been a hot topic during the last 5 years due its association with increased morbidity and mortality. CIN is an important complication, particularly in patients with advanced chronic kidney disease (CKD) associated with diabetes mellitus. Methods to diminish the incidence of CIN have been highly contentious. They include choice of contrast, pharmacologic manipulation, and volume expansion. The pathophysiology of this complication remains uncertain, but reduction in renal blood flow and direct toxicity of tubular cells has been implicated. More than 900 publications under the heading CIN have been published during the last 5 years. Fewer than 5% of these publications are randomized prospective controlled studies. In spite of the large number of reports on CIN, very little has been changed. The use of the smallest possible dose of low- or iso-osmolar contrast media, volume expansion, stopping nephrotoxic drugs, and avoiding repeat contrast injections within 48 hours remain the most effective approach to reduce the risk of CIN.

Need for coronary artery bypass grafting in Newfoundland and Labrador: the impact of increased demand.

BACKGROUND: In the past decade, growth of coronary revascularization in Canada has been substantial. It was hypothesized that as coronary angiography (CA) rates increased, referral for necessary coronary artery bypass grafting (CABG) would also increase, and include patients with multivessel disease and class I to III angina who required elective surgery. Furthermore, it was proposed that the number of CABG surgeries needed would increase at a similar rate to that of CA. METHODS: An incident cohort of patients who received CA in 1998/1999 was identified, and the group referred for CABG was followed. Clinical characteristics, appropriateness and necessity scores using specific criteria, and waiting times were evaluated and compared with a similar cohort from 1994/1995. Utilization data for coronary revascularization procedures from 1994 to 2002 were reviewed. RESULTS: Between 1994/1995 and 1998/1999, the number of CAs per year increased by 37%. The inappropriateness rate for CA was 4% in 1998/1999. The proportion of patients diagnosed with critical coronary artery disease increased from 68% in 1994/1995 to 74% in 1998/1999. The number referred for CABG increased by 48%, and the number for percutaneous transluminal coronary angioplasty (PTCA) increased by 137%. The increase in the number referred for CABG was attributable to the increase in the number of patients with less severe symptoms who required delayed elective CABG. The necessity rate for CABG in the referred group was 94% in 1994/1995 and 95% in 1998/1999. A further 91 patients were identified who needed CABG but did not receive it, 86% of whom had PTCA. From 1999 to 2002, the annual growth rate in those referred for CABG was higher than the growth rate for CA. CONCLUSIONS: With the growth in CA, the rate of discovery of high risk coronary anatomy actually increased. Growth in CABG volume was attributable to growth in the need for elective surgery in patients with class I to III angina. The rate of CABG increased disproportionately to the rate of CA, despite higher rates of PTCA with stenting. It is likely that the demand for CABG will continue to rise steadily, as expansion of angiography occurs, and may be higher than expected from the growth in CA.

Identifying and slowing progressive chronic renal failure.

OBJECTIVE: To help inform primary care physicians about how to identify and slow progressive chronic renal failure. QUALITY OF EVIDENCE: The National Library of Medicine (1996 to 2000) was searched using PubMed with search terms pertinent to studies on identification, course, and management of chronic renal failure. References in retrieved papers and older literature known to the authors supplemented the searches. In general, sufficient high-quality studies, systematic reviews, or guidelines based on such evidence were available to support our main points. MAIN MESSAGE: End-stage renal disease (ESRD) poses a large and growing morbidity, mortality, and financial burden. Almost all patients reach ESRD as a result of chronic progressive conditions, particularly diabetic nephropathy, hypertensive-vascular renal disease, and glomerular disorders. Patients at risk merit regular renal assessment with serum creatinine tests and urinalysis. Persistent high blood pressure and heavy proteinuria are the strongest predictors of progression of chronic renal failure. Patients with renal disease should be examined and treated for vascular disease and vice versa. Blood pressure lowering, ACE inhibition, and avoidance of further renal insults (such as use of nephrotoxins) can slow the decline of renal function. Restricting dietary protein has a weak effect on slowing renal failure and is not easy to apply in primary care. Timely involvement of specialized nephrology teams is important. CONCLUSION: Family physicians play an important role in recognizing patients with potential for renal failure, in demonstrating progressive chronic renal failure, and in initiating therapy early to improve outcomes.

Comparative hospitalization of hemodialysis and peritoneal dialysis patients in Canada.

BACKGROUND: Most comparisons of hemodialysis (HD) and peritoneal dialysis (PD) have used mortality as an outcome. Relatively few studies have directly compared the hospitalization rates, an outcome of perhaps equal importance, of patients using these different dialysis modalities. METHODS: Eight hundred twenty-two consecutive patients at 11 Canadian institutions with irreversible renal failure had an extensive assessment of comorbid illness and initial mode of dialysis collected prospectively immediately prior to starting dialysis therapy. The cohort was assembled between March 1993 and November 1994. The mean follow-up was 24 months. Admission data were used to compare hospitalization rates in HD and PD. RESULTS: Thirty-four percent of patients at baseline and 50% at three months used PD. Twenty-five percent of HD and 32% of PD patients switched dialysis modality at least once after their first treatment (P = NS). Nine percent of HD patients and 30% of PD patients switched modality after three months (P < 0. 001). Total comorbidity was higher in HD patients at baseline (P < 0. 001) and at three months (P = 0.001). The overall hospitalization rate was 40.2 days per 1000 patient days after baseline and 38.0 days per 1000 patient days after three months. When an adjustment was made for baseline comorbid conditions, patients on PD had a lower rate of hospitalization in intention-to-treat analysis according to the type of dialysis in use at baseline (RR 0.85, 95% CI, 0.82 to 0.87, P < 0.001), but a higher rate according to the type of dialysis in use three months after study entry (RR 1.31, 95% CI, 1.27 to 1.34, P < 0.001). In analyses based on the amount of time actually spent on each treatment modality, PD was associated with a higher rate of hospitalization when analyzed according to the type of dialysis in use at baseline (RR 1.10, 95% CI, 1.07 to 1.13, P < 0.001) and according to the type of dialysis in use three months after study entry (RR 1.26, 95% CI, 1.23 to 1.30, P < 0.001). CONCLUSIONS: Conclusions regarding comparative hospitalization rates are heavily dependent on the analytic starting point and on whether intention-to-treat or treatment-received analyses are used. When early treatment switches are accounted for, HD is associated with a lower rate of hospitalization than PD, but the effect is modest.

Comparative mortality of hemodialysis and peritoneal dialysis in Canada.

BACKGROUND: Comparisons of mortality rates in patients on hemodialysis versus those on peritoneal dialysis have been inconsistent. We hypothesized that comorbidity has an important effect on differential survival in these two groups of patients. METHODS: Eight hundred twenty-two consecutive patients at 11 Canadian institutions with irreversible renal failure had an extensive assessment of comorbid illness collected prospectively, immediately prior to starting dialysis therapy. The cohort was assembled between March 1993 and November 1994; vital status was ascertained as of January 1, 1998. RESULTS: The mean follow-up was 24 months. Thirty-four percent of patients at baseline, 50% at three months, and 51% at six months used peritoneal dialysis. Values for a previously validated comorbidity score were higher for patients on hemodialysis at baseline (4.0 vs. 3.1, P < 0.001), three months (3.7 vs. 3.2, P = 0.001), and six months (3.6 vs. 3.2, P = 0.005). The overall mortality was 41%. The unadjusted peritoneal dialysis/hemodialysis mortality hazard ratios were 0.65 (95% CI, 0. 51 to 0.83, P = 0.0005), 0.84 (95% CI, 0.66 to 1.06, P = NS), and 0. 83 (95% CI, 0.64 to 1.08, P = NS) based on the modality of dialysis in use at baseline, three months, and six months, respectively. When adjusted for age, sex, diabetes, cardiac failure, myocardial infarction, peripheral vascular disease, malignancy, and acuity of renal failure, the corresponding hazard ratios were 0.79 (95% CI, 0. 62 to 1.01, P = NS), 1.00 (95% CI, 0.78 to 1.28, P = NS), and 0.95 (95% CI, 0.73 to 1.24, P = NS). Adjustment for a previously validated comorbidity score resulted in hazard ratios of 0.74 (95% CI, 0.58 to 0.94, P = 0.01), 0.94 (95% CI, 0.74 to 1.19, P = NS), and 0.88 (95% CI, 0.68 to 1.13, P = NS) at baseline, three months, and six months. There was no survival advantage for either modality in any of the major subgroups defined by age, sex, or diabetic status. CONCLUSIONS: The apparent survival advantage of peritoneal dialysis in Canada is due to lower comorbidity and a lower burden of acute onset end-stage renal disease at the inception of dialysis therapy. Hemodialysis and peritoneal dialysis, as practiced in Canada in the 1990s, are associated with similar overall survival rates.

Elevated levels of serum creatinine: recommendations for management and referral.

BACKGROUND: The potential benefits of earlier referral to a nephrologist of patients with elevated levels of serum creatinine include identifying and treating reversible causes of renal failure, slowing the rate of decline associated with progressive renal insufficiency, managing the coexisting conditions associated with chronic renal failure and facilitating efficient entry into dialysis programs for all patients who might benefit. METHODS: A subcommittee of the Canadian Society of Nephrology, which included representatives from family practice and internal medicine, conducted a MEDLINE search for the period 1966 to 1998 using the key words referral and consultation, dialysis, hemodialysis, peritoneal dialysis, renal replacement therapy and kidney diseases. Where published evidence was lacking, conclusions were reached by consensus. GUIDELINES: Earlier referral to nephrologists of patients with elevated creatinine levels is expected to lead to better health care outcomes and lower costs for both the patients and the health care system. All patients with newly discovered renal insufficiency (as evidenced by serum creatinine elevated to a level above the upper limit of the normal range of that laboratory, adjusted for age and height in children) must undergo investigations to determine the potential reversibility of disease, to evaluate the prognosis and to optimize planning of care. All patients with an established, progressive increase in serum creatinine level should be followed with a nephrologist. Adequate preparation for dialysis or transplantation (or both) requires at least 12 months of relatively frequent contact with a renal care team. Nephrologists should provide consultation in a timely manner for any patient with an elevated serum creatinine level. In addition, they should provide advice about what aspects of the condition require particularly urgent or emergency assessment. SPONSORS: This clinical practice guideline has been endorsed by the Canadian Society of Nephrology and the College of Family Physicians of Canada. Meeting, teleconference and travel expenses of the Referral Guideline Subcommittee were covered by The Momentum Program, a collaboration between Baxter Corp. and Janssen-Ortho Inc. However, the authors are solely responsible for the editorial content of this article.

Prevalence and correlates of elevated serum creatinine levels: the Framingham Heart Study.

BACKGROUND: Elevated serum creatinine (SCr) levels are a predictor of end-stage renal disease, but little is known about the prevalence of elevated SCr levels and their correlates in the community. METHODS: In this cross-sectional, community-based sample, SCr levels were measured in 6233 adults (mean age, 54 years; 54% women) who composed the "broad sample" of this investigation. A subset, consisting of 3241 individuals who were free of known renal disease, cardiovascular disease, hypertension, and diabetes, constituted the healthy reference sample. In this latter sample, sex-specific 95th percentiles for SCr levels (men, 136 micromol/L [1.5 mg/dL]; women, 120 micromol/L [1.4 mg/dL]) were labeled cutpoints. These cutpoints were applied to the broad sample in a logistic regression model to identify prevalence and correlates of elevated SCr levels. RESULTS: The prevalence of elevated SCr levels was 8.9% in men and 8.0% in women. Logistic regression in men identified age, treatment for hypertension (odds ratio [OR], 1.75; 95% confidence interval [CI], 1.27-2.42), and body mass index (OR, 1.08; 95% CI, 1.01-1.15) as correlates of elevated SCr levels. Additionally, men with diabetes who were receiving antihypertensive medication were more likely to have raised SCr values (OR, 2.94; 95% CI, 1.60-5.39). In women, age, use of cardiac medications (OR, 1.58; 95% CI, 1.10-2.96), and treatment for hypertension (OR, 1.42; 95% CI, 1.07-1.87) were associated with elevated SCr levels. CONCLUSIONS: Elevated SCr levels are common in the community and are strongly associated with older age, treatment for hypertension, and diabetes. Longitudinal studies are warranted to determine the clinical outcomes of individuals with elevated levels of SCr and to examine factors related to the progression of renal disease in the community.

Managing progressive renal disease before dialysis.

OBJECTIVE: To enhance awareness of issues affecting patients with chronic renal failure and to provide guidance for primary care practitioners managing such patients. QUALITY OF EVIDENCE: Randomized trials establish the efficacy of blood pressure control and angiotensin-converting enzyme (ACE) inhibition in slowing the progression of chronic renal disease. Some randomized trials and many prospective studies address management of anemia, hyperparathyroidism, and multidisciplinary predialysis care. The benefits of lipid lowering are suggested by randomized trials among patients without renal disease. MAIN MESSAGE: Progression of renal failure, particularly in patients with proteinuria, can be slowed by lowering blood pressure. Angiotensin-converting enzyme inhibitors are more beneficial than other antihypertensives in this situation. Partial correction of anemia with iron, erythropoietin, or androgens can improve quality of life and potentially prevent cardiac disease. Renal bone disease and secondary hyperparathyroidism can be prevented in part by early dietary phosphate restriction, use of calcium-containing phosphate binders, and activated vitamin D. Correction of acidosis could improve protein metabolism and bone and cardiovascular health. Treatment of hyperlipidemia might reduce cardiovascular disease. Early involvement of a nephrology-based multidisciplinary team has the potential to reduce morbidity and costs, enhance patients' knowledge of their condition, and prolong the period before dialysis is required. CONCLUSIONS: Care of patients with progressive renal failure is complex and requires attention to detail. Family doctors play a vital role in these efforts and should be involved in all aspects of care.

Analgesic nephropathy.

Many questions about analgesic nephropathy (AN) lack clear-cut answers. We present available evidence for and against proposed answers to many of these questions. These include: (1) Is acetaminophen (AC) nephrotoxic when taken as the sole analgesic? (2) Is the combination of acetylsalicylic acid (ASA) and AC more nephrotoxic than AC taken alone, and if so, why? (3) What are the minimum doses and durations of ingestion required to produce analgesic nephrotoxicity? (4) Is the combination of ASA and AC (a major metabolite of phenacetin) less nephrotoxic than that of phenacetin and ASA combined? (5) Does caffeine in combination with analgesics contribute to nephrotoxicity? (6) What is the incidence of end-stage renal disease (ESRD) due to AN? (7) What uniform diagnostic criteria should be established for AN? (8) What are the earliest anatomic and biochemical abnormalities? (9) What are the mechanisms of renal injury? (10) Does AC cause uroepithelial neoplasia? (11) What research might be most beneficial? Based mainly on associations, some strong, we suggest that AN still exists as a cause of ESRD in the United States, where AC/ASA combinations are available over the counter, and in Canada, where they are not. We also suggest that the evidence needed to recommend that the AC/ASA combination be excluded from over-the-counter analgesic preparations still has limitations. A prospective multicenter study comparing incidence related to AC/ASA in the United States and to AC in Canada and the United States may be needed to answer this question. For such a study to be worthwhile, an adequate incidence in both countries is required.

Safety and criteria for selective use of low-osmolality contrast for cardiac angiography.

OBJECTIVES: Recommendations to restrict low-osmolality contrast to high-risk patients having cardiac angiography have been challenged because of safety and uncertainty about selection criteria. The authors document frequency and severity of adverse events with diagnostic cardiac angiography under the influence of guidelines for selective use of low-osmolality contrast in high-risk patients and refine high-risk criteria. METHODS: Subjects of this prospective cohort study were 7,448 unselected patients having diagnostic cardiac angiography in St. John's, Newfoundland or Ottawa, Ontario. Measures included prespecified risk factors, procedure, contrast, and adverse events such as death within 24 hours, myocardial infarction, stroke, arrhythmias, hypotension, and anaphylactoid reactions. RESULTS: Patients were similar at both sites. Fourteen point two percent received low-osmolality nonionic agents in St. John's. Thirty-four point one percent received low-osmolality (mostly ionic) media in Ottawa. Overall adverse event rates were similar at both sites: death, 0.07%; myocardial infarction or stroke, 0.03%; moderate events, 2%; and mild events, 16.8%. Event rates were low in those given high-osmolality media: death, 0.02%; myocardial infarction or stroke, 0.24%; moderate events, 1.6%; and mild events, 18%. The risk with cardiogenic shock and prior severe reaction to contrast could not be examined, but otherwise only current heart failure and markers of recent ischemia were associated with events after high-osmolality media. CONCLUSIONS: Clinicians, using guidelines, can identify high-risk patients and should be able to safely limit use of low-osmolality media to them.

Patients' perceptions of their experiences with ESRD and hemodialysis treatment.

A grounded theory methodology was used to explore patients' experiences with end-stage renal disease (ESRD) and hemodialysis. The emerging theory suggests that a "new sense of self" is an emotional/psychological state that fluctuates with the evolving meanings of illness and treatment and perceived quality of supports. The findings indicate that when confronted with this new way of being in the world, the individual becomes cognizant of an uncertain future, continued dependence on life-sustaining technology and the expertise of health care providers, and the demands on and sacrifices incurred by significant others. All aspects of patients' experiences with ESRD and hemodialysis treatment must be considered if health care providers are to facilitate positive health outcomes.

The efficiency of acute care bed utilization in Newfoundland and Labrador.

Hospital efficiency is closely related to utilization levels and length of stay. This study determined whether inappropriate bed utilization in Newfoundland was related to inefficiency or inadequate access to alternative services. It also compared Canadian Institute for Health information (CIHI) data to our survey to determine whether they provide comparable information for monitoring efficiency. Inappropriate acute care days were identified using a modified Appropriateness Evaluation Protocol. Average length of stay (ALOS) by service for each of the province's acute care institutions was also reviewed from 1993-94 to 1995-96 using the CIHI database. Hospital admissions were Inappropriate in 14.2 percent of 2,007 cases. Of the 14,194 days of care, 22.8 percent were inappropriate, with most (16.4 percent) being avoidable with better use of existing resources. Of the inappropriate days, 49.2 percent related to physicians' functions. The provincial ALOS fell from 5.70 days in 1993-94 to 5.39 days in 1995-96, but remains 10.5 percent above the national average.

Prediction of early death in end-stage renal disease patients starting dialysis.

Demand for dialysis for patients with end-stage renal disease is growing, as is the comorbidity of dialysis patients. Accurate prediction of those destined to die quickly despite dialysis could be useful to patients, providers, and society in making decisions about starting dialysis. To determine whether age and comorbidity accurately predict death within 6 months of first dialysis for end-stage renal disease, a prospective cohort study of 822 patients starting dialysis at one of 11 Canadian centers was performed. Patient characteristics were recorded at first dialysis. Follow-up continued until death or study end (at least 6 months after enrollment). One hundred thirteen of 822 (13.7%) patients died within 6 months. Although an existing scoring system predicted prognosis, adverse scores greater than 9 were found in only 9.7% of those who died; only 52% of those who scored higher than 9 died within 6 months. No score cutoff point combined high true-positive and low false-positive rates for predicting early death. Age, severity of heart failure or peripheral vascular disease, arrhythmias, malnutrition, malignancy, or myeloma were independent prognostic factors identified in multivariate models. However, the best fit discriminant and logistic models were also unable to accurately predict death within 6 months. Clinicians were very accurate in assigning patients to prognostic groups up to a 50% risk of death by 6 months, above which they tended to overestimate risk. However, clinicians were only marginally better than the predictive models in determining whether a given high-risk patient would die. The inability of a scoring system or clinical intuition to accurately predict death soon after starting dialysis for end-stage renal disease suggests that limiting access to dialysis on the basis of likely short survival may be inappropriate in Canada.

Detection and classification of inappropriate hospital stay.

OBJECTIVE: To study the reliability and validity of concurrent review of hospital-bed utilization carried out by a trained nurse. DESIGN: Analysis of interrater reliability and validity of utilization review. SETTING: Tertiary care hospital associated with a university. PATIENTS: Eighty patients randomly selected from 203 patients admitted to the hospital. INTERVENTIONS: Appropriateness of days of stay in hospital was classified prospectively, on the basis of clinical judgement, by two nurses working independently, by a third nurse working with the Appropriateness Evaluation Protocol (AEP) and by a multidisciplinary review panel of nurses and physicians working retrospectively with the use of data gathered by the first nurse. MAIN OUTCOME MEASURES: Agreement between different rates on the number of and reason for inappropriate admission days, total number of inappropriate days and of inappropriate days due to delayed discharge, to diagnostic procedures or to inefficient medical management. RESULTS: Agreement between the two nurses who used clinical judgement was substantial (kappa or the intraclass correlation coefficient [RI] 0.77 to 0.98 on the number of and reason for inappropriate admission days, on the total number of inappropriate hospital days and on days due to delayed discharge, diagnostic procedures or inefficient medical management. Agreement was moderate (RI 0.47) on the number of inappropriate day's stay awaiting surgery. Agreement was substantial (kappa or RI 0.69 to 0.94) between the two nurses who used clinical judgement and the panel, except on the total number of inappropriate days; however, for this variable, exclusion of one case increased the RI from 0.35 to 0.80. Agreement was substantial between the two nurses who used clinical judgement and the nurse who used the AEP on appropriateness of admission days and the number of inappropriate days. Agreement between the panel and the nurse who used the AEP on the number of inappropriate days rose from 0.36 to 0.88 when the one outlying case was excluded. Some admissions were classified as premature when the AEP was used, whereas other raters considered the admissions unnecessary. There was poor agreement between the nurse who used the AEP and the other raters on the number of inappropriate days' stay awaiting surgery or diagnostic tests. CONCLUSIONS: Data collection and judgement of appropriateness of hospital stay by a trained nurse is feasible and reliable. A nurse working prospectively and a panel working retrospectively sometimes disagree. The AEP provides a similar estimate of the number of inappropriate days but may be insensitive to patient factors that influence the timing of admission.

Acetaminophen and adverse chronic renal outcomes: an appraisal of the epidemiologic evidence.

This article critically reviews existing epidemiologic studies of the association between habitual acetaminophen use and chronic renal disease exclusive of neoplasia. Relevant primary studies were identified by searching the Medline database from 1966 to March 1995. There are several case reports of analgesic nephropathy following exposure to acetaminophen alone, but the accuracy with which other causes of this lesion were excluded is unclear. Three case control studies have found an increased risk (odds ratio range, 2 to 4) with habitual acetaminophen exposure for papillary necrosis, chronic renal failure, or end-stage renal disease. These studies have been open to confounding by indication. It is also difficult to determine the risk with acetaminophen alone given the prevalent use of analgesic mixtures in the populations studied. Two prospective cohort studies have suggested an increased risk of renal impairment or papillary calcification following regular analgesic exposure. One of these studies was of subjects taking phenacetin-containing analgesic mixtures and the study population of the other was too small to reach statistically significant conclusions. Recent study results have raised the possibility that habitual acetaminophen use could increase the likelihood or rate of progression of chronic renal disease in general. This review suggests that there is currently insufficient evidence to conclude that habitual use of acetaminophen as a sole analgesic is associated with an increased risk of chronic renal disease. Further research is required to examine this question. Prudence suggests that habitual use of acetaminophen should be discouraged in the absence of strong medical indications.