Mitchell F. Berman

The epidemiology of postpartum hemorrhage in a large, nationwide sample of deliveries.

BACKGROUND: In this study, we sought to (1) define trends in the incidence of postpartum hemorrhage (PPH), and (2) elucidate the contemporary epidemiology of PPH focusing on risk factors and maternal outcomes related to this delivery complication. METHODS: Hospital admissions for delivery were extracted from the Nationwide Inpatient Sample, the largest discharge dataset in the United States. Using International Classification of Diseases, Clinical Modification (ninth revision) codes, deliveries complicated by PPH were identified, as were comorbid conditions that may be risk factors for PPH. Temporal trends in the incidence of PPH from 1995 to 2004 were assessed. Logistic regression was used to identify risk factors for the most common etiology of PPH—uterine atony. RESULTS: In 2004, PPH complicated 2.9% of all deliveries; uterine atony accounted for 79% of the cases of PPH. PPH was associated with 19.1% of all in-hospital deaths after delivery. The overall rate of PPH increased 27.5% from 1995 to 2004, primarily because of an increase in the incidence of uterine atony; the rates of PPH from other causes including retained placenta and coagulopathy remained relatively stable during the study period. Logistic regression modeling identified age <20 or ≥40 years, cesarean delivery, hypertensive diseases of pregnancy, polyhydramnios, chorioamnionitis, multiple gestation, retained placenta, and antepartum hemorrhage as independent risk factors for PPH from uterine atony that resulted in transfusion. Excluding maternal age and cesarean delivery, one or more of these risk factors were present in only 38.8% of these patients. CONCLUSION: PPH is a relatively common complication of delivery and is associated with substantial maternal morbidity and mortality. It is increasing in frequency in the United States. PPH caused by uterine atony resulting in transfusion often occurs in the absence of recognized risk factors.

Impact of Hospital-Related Factors on Outcome After Treatment of Cerebral Aneurysms

BACKGROUND AND PURPOSE The goal of this study was to examine the impact of hospital characteristics on outcome after the treatment of ruptured and unruptured cerebral aneurysms. METHODS We identified all discharges in New York State from 1995 through 2000 with a principal diagnosis of subarachnoid hemorrhage (SAH) or unruptured cerebral aneurysm (UCA) in patients who were treated by aneurysm clipping, wrapping, or endovascular coiling. An adverse outcome was defined as in-hospital death or discharge to a rehabilitation hospital or long-term facility. We examined the effect of hospital factors, including the rate of endovascular therapy and overall procedural volume, on outcome, length of stay, and total charges. RESULTS There were 2200 (36.9%) and 3763 (63.1%) admissions for attempted treatment of UCA and SAH, respectively. The 10 highest-volume hospitals performed half of all the procedures. Overall, hospital volume was associated with fewer adverse outcomes and lower in-hospital mortality for both UCA (adverse outcome: odds ratio [OR], 0.89; P<0.0001; mortality: OR, 0.94; P=0.002 for each 10 additional procedures performed per year) and SAH (adverse outcome: OR, 0.94; P=0.03; mortality: OR, 0.95; P=0.005). Use of endovascular therapy (each additional 10% of cases performed endovascularly) was associated with fewer adverse outcomes after treatment of unruptured aneurysm (0.83, P=0.026). Hospital volume had more of an effect on outcome after aneurysm clipping than after endovascular therapy. CONCLUSIONS Hospital procedural volume and the propensity of a hospital to use endovascular therapy are both independently associated with better outcome. Improvement in outcome could be achieved by a program of regionalization and selective referral for the treatment of cerebral aneurysms.

The epidemiology of brain arteriovenous malformations.

OBJECTIVE Common estimates of the prevalence rate for pial arteriovenous malformations (AVMs) of the brain vary widely, and their accuracy is questionable. Our objective was to critically review the original sources from which these rates were derived and to establish best estimates for both the incidence and prevalence of the disease. METHODS We reviewed all of the relevant original literature: autopsy series, the Cooperative Study of Intracranial Aneurysms and Subarachnoid Hemorrhage and related analyses, and other population-based studies. We also modeled the confidence intervals of estimates for a process of low prevalence such as AVMs. RESULTS Many of the prevalence estimates (500-600/100,000 population) were based on autopsy data, a source that is inherently biased. Other estimates (140/100,000 population) originated from an inappropriate analysis of data from the Cooperative Study. The most reliable information comes from a population-based study of Olmsted County, MN, but prevalence data specific to AVMs was not found in that study. CONCLUSION The estimates for AVM prevalence that are published in the medical literature are unfounded. Because of the rarity of the disease and the existence of asymptomatic patients, establishing a true prevalence rate is not feasible. Owing to variation in the detection rate of asymptomatic AVMs, the most reliable estimate for the occurrence of the disease is the detection rate for symptomatic lesions: 0.94 per 100,000 person-years (95% confidence interval, 0.57-1.30/100,000 person-years). This figure is derived from a single population-based study, but it is supported by a reanalysis of other data sources. The prevalence of detected, active (at risk) AVM disease is unknown, but it can be inferred from incidence data to be lower than 10.3 per 100,000 population.

Intracerebral hemorrhage in pregnancy: Frequency, risk factors, and outcome

Objective: To describe the frequency, risk factors, and outcome of intracerebral hemorrhage (ICH) in pregnancy and the postpartum period using a large database of US inpatient hospitalizations. Methods: The authors obtained data from an administrative dataset, the Nationwide Inpatient Sample, which includes approximately 20% of all discharges from non-Federal hospitals, for the years 1993 through 2002. Women aged 15 to 44 years with a diagnosis of ICH were selected from the database for analysis, and within this group patients coded as pregnant or postpartum were identified. Using US Census data, estimates were made of the rates of ICH in pregnant/postpartum and non-pregnant women. Rates of various comorbidities in patients with pregnancy-related ICH were compared to the rates found in the general population of delivering patients using multivariate logistic regression to identify independent risk factors for pregnancy-related ICH. Results: The authors identified 423 patients with pregnancy-related ICH, which corresponded to 6.1 pregnancy-related ICH per 100,000 deliveries and 7.1 pregnancy-related ICH per 100,000 at-risk person-years (compared to 5.0 per 100,000 person-years for non-pregnant women in the age range considered). The increased risk of ICH associated with pregnancy was largely attributable to ICH occurring in the postpartum period. The in-hospital mortality rate for pregnancy-related ICH was 20.3%. ICH accounted for 7.1% of all pregnancy-related mortality recorded in this database. Significant independent risk factors for pregnancy-related ICH included advanced maternal age (OR 2.11, 95% CI 1.69 to 2.64), African American race (OR 1.83, 95% CI 1.39 to 2.41), preexisting hypertension (OR 2.61, 95% CI 1.34 to 5.07), gestational hypertension (OR 2.41, 95% CI 1.62 to 3.59), preeclampsia/eclampsia (OR 10.39, 95% CI 8.32 to 12.98), preexisting hypertension with superimposed preeclampsia/eclampsia (OR 9.23, 95% CI 5.26 to 16.19), coagulopathy (OR 20.66, 95% CI 13.67 to 31.23), and tobacco abuse (OR 1.95, 95% CI 1.11 to 3.42). Conclusion: Intracerebral hemorrhage (ICH) accounts for a substantial portion of pregnancy-related mortality. The risk of ICH associated with pregnancy is greatest in the postpartum period. Advanced maternal age, African American race, hypertensive diseases, coagulopathy, and tobacco abuse were all independent risk factors for pregnancy-related ICH.

Perioperative acute ischemic stroke in noncardiac and nonvascular surgery: incidence, risk factors, and outcomes.

Background:Perioperative acute ischemic stroke (AIS) is a recognized complication of noncardiac, nonvascular surgery, but few data are available regarding incidence and effect on outcome. This study examines the epidemiology of perioperative AIS in three common surgeries: hemicolectomy, total hip replacement, and lobectomy/segmental lung resection. Methods:Discharges for patients aged 18 yr or older who underwent any of the surgical procedures listed above were extracted from the Nationwide Inpatient Sample, an administrative database that contains 20% of all discharges from non-Federal hospitals each year, for years 2000 to 2004. Using appropriate International Classification of Diseases, 9th revision, Clinical Modification codes, patients with perioperative AIS were identified, as were comorbid conditions that may be risk factors for perioperative AIS. Multivariate logistic regression was performed to identify independent predictors of perioperative AIS and to ascertain the effect of AIS on outcome. Results:A total of 0.7% of 131,067 hemicolectomy patients, 0.2% of 201,235 total hip replacement patients, and 0.6% of 39,339 lobectomy/segmental lung resection patients developed perioperative AIS. For patients older than 65 yr, AIS rose to 1.0% for hemicolectomy, 0.3% for hip replacement, and 0.8% for pulmonary resection. Multivariate logistic regression analysis revealed renal disease (odds ratio, 3.0), atrial fibrillation (odds ratio, 2.0), history of stroke (odds ratio, 1.6), and cardiac valvular disease (odds ratio, 1.5) to be the most significant risk factors for perioperative AIS. Conclusions:Perioperative AIS is an important source of morbidity and mortality associated with noncardiac, nonvascular surgery, particularly in elderly patients and patients with atrial fibrillation, valvular disease, renal disease, or previous stroke.

The risk and outcomes of epidural hematomas after perioperative and obstetric epidural catheterization: a report from the Multicenter Perioperative Outcomes Group Research Consortium.

BACKGROUND:In this study, we sought to determine the frequency and outcomes of epidural hematomas after epidural catheterization. METHODS:Eleven centers participating in the Multicenter Perioperative Outcomes Group used electronic anesthesia information systems and quality assurance databases to identify patients who had epidural catheters inserted for either obstetrical or surgical indications. From this cohort, patients undergoing laminectomy for the evacuation of hematoma within 6 weeks of epidural placement were identified. RESULTS:Seven of 62,450 patients undergoing perioperative epidural catheterizations developed hematoma requiring surgical evacuation. The event rate was 11.2 × 10−5 (95% confidence interval [CI], 4.5 × 10−5 to 23.1 × 10−5). Four of the 7 had anticoagulation/antiplatelet therapy that deviated from American Society of Regional Anesthesia guidelines. None of 79,837 obstetric patients with epidural catheterizations developed hematoma (upper limit of the 95% CI, 4.6 × 10−5). The hematoma rate in obstetric epidural catheterizations was significantly lower than in perioperative epidural catheterizations (P = 0.003). CONCLUSIONS:In this series, the 95% CI for the frequency of epidural hematoma requiring laminectomy after epidural catheter placement for perioperative anesthesia/analgesia was 1 event per 22,189 placements to 1 event per 4330 placements. Risk was significantly lower in obstetric epidurals.

Meningioma resection in the elderly: nationwide inpatient sample, 1998-2002.

OBJECTIVE:Morbidity and mortality rates reported for meningioma resection in the elderly vary widely. Thus, it is difficult for neurosurgeons to compare the risks and benefits of operating on elderly patients against opting for radiosurgery or watchful waiting. To address this issue, we studied the effect of advanced age on outcome after meningioma resection using the Nationwide Inpatient Sample. METHODS:We identified all patients over the age of 20 in the Nationwide Inpatient Sample database who underwent surgical resection of a meningioma between 1998 and 2002 and were admitted from home. Primary outcomes were in-hospital mortality, adverse outcome (defined as death or discharge to a facility other than home), and length of hospitalization. Multivariate models were constructed to assess the effect of elderly age on the primary outcomes, adjusting for patient demographics, comorbid medical conditions, and hospital surgical volume. RESULTS:There were 8861 patients in the Nationwide Inpatient Sample database who underwent resection of meningioma during the study period; 26.0% were age 70 or older. Each of the primary outcomes demonstrated a marked effect of advancing age. The in-hospital mortality rate was higher in the elderly than in the nonelderly (4.0% versus 1.1%, P < 0.001), as was the rate of discharge to a facility other than home (53.2% versus 16.6%, P < 0.001). Elderly patients also had a longer mean length of stay (7.2 versus 5.1 d P < 0.001). CONCLUSION:The association between elderly age and adverse outcome after meningioma resection suggests a note of caution before proceeding to surgery with these patients.

Single sodium channels from canine ventricular myocytes: voltage dependence and relative rates of activation and inactivation.

1. Single sodium channel currents were recorded from canine ventricular myocytes in cell‐attached patches. The relative rates of single‐channel activation vs. inactivation as well as the voltage dependence of the rate of open‐channel inactivation were studied. 2. Ensemble‐averaged sodium currents showed relatively normal activation and inactivation kinetics, although the mid‐point of the steady‐state inactivation (h infinity) curve was shifted by 20‐30 mV in the hyperpolarizing direction. This shift was due to the bath solution, which contained isotonic KCl to depolarize the cell to 0 mV. 3. Steady‐state activation showed less of a voltage shift. The threshold for eliciting channel opening was around ‐70 mV and the mid‐point of activation occurred near ‐50 mV. 4. The decline of the ensemble‐averaged sodium current during a maintained depolarization was fitted by a single exponential function characterizing the apparent time constant of inactivation (tau h). The apparent rate of inactivation was voltage dependent, with tau h decreasing e‐fold for a 15.4 mV depolarization. 5. The relative contributions of the rates of single‐channel activation and inactivation in determining the time course of current decay (tau h) were examined using the approach of Aldrich, Corey & Stevens (1983). Mean channel open time (tau o) showed significant voltage dependence, increasing from 0.5 ms at ‐70 mV to around 0.8 ms at ‐40 mV. At ‐70 mV tau h was much greater than tau o, while at ‐40 mV the two time constants were similar. 6. The degree to which the kinetics of single‐channel activation contribute to tau h was studied using the first latency distribution. The first latency function was fitted by two exponentials. The slow component was voltage dependent, decreasing from 19 ms at ‐70 mV to 0.5 ms at ‐40 mV. The fast component (0.1‐0.5 ms) was not well resolved. 7. Comparing the first latency distribution with the time course of the ensemble‐averaged sodium current at ‐40 mV showed that activation is nearly complete by the time of peak inward sodium current. However, at ‐70 mV, activation overlaps significantly with the apparent time course of inactivation of the ensemble‐averaged current. 8. Using the methods of Aldrich et al. (1983) we also measured the apparent rate of open‐channel closing (a) and open‐channel inactivation (b). Both rates were voltage dependent, with a showing an e‐fold decrease for an 11 mV depolarization and b showing an e‐fold increase for a 30 mV depolarization.(ABSTRACT TRUNCATED AT 400 WORDS)

Temporal trends in the epidemiology of severe postoperative sepsis after elective surgery: a large, nationwide sample.

Introduction:Multiple studies have used administrative datasets to examine the epidemiology of sepsis in general, but the entity of postoperative sepsis has been studied less intensively. Therefore, we undertook an analysis of the epidemiology of postoperative sepsis using the Nationwide Inpatient Sample, the largest in-patient dataset available in the United States. Methods:Elective admissions of patients aged 18 yr or older with a length of stay more than 3 days for any 1 of the 20 most common elective operative procedures were extracted from the dataset for the years 1997–2006. Postoperative sepsis was defined using the appropriate International Classification of Diseases, Ninth Revision, Clinical Modification codes; severe sepsis was defined as sepsis along with organ dysfunction. Logistic regression was used to assess the significance of temporal trends after adjusting for relevant demographic characteristics, operative procedure, and comorbid conditions. Results:We identified 2,039,776 admissions for analysis. The rate of severe sepsis increased from 0.3% in 1997 to 0.9% in 2006. This trend persisted after adjusting for relevant covariables—the adjusted odds ratio of severe sepsis per year increase in the study period was 1.12 (95% CI, 1.11–1.13; P < 0.001). The in-hospital mortality rate for patients with severe postoperative sepsis declined from 44.4% in 1997 to 34.0% in 2006; this trend also persisted after adjustment for relevant covariables—the adjusted odds ratio per year was 0.94 (95% CI, 0.93–0.95; P < 0.001). Conclusion:During the 10-yr period that we studied, there was a marked increase in the rate of severe postoperative sepsis but a concomitant decrease in the in-hospital mortality rate in severe sepsis.

Dexmedetomidine may impair cognitive testing during endovascular embolization of cerebral arteriovenous malformations: a retrospective case report series.

After the reported successful use of dexmedetomidine to sedate patients in the intensive care unit without respiratory depression, we began to use dexmedetomidine for interventional neuroradiologic procedures. We report on five patients who had dexmedetomidine administered for sedation during embolization of cerebral arteriovenous malformations. All patients were comfortably sedated and breathing spontaneously. However, although patients were awake and following simple commands 10 minutes after the discontinuation of the infusion of dexmedetomidine, they were nevertheless unable to undergo cognitive testing. They were still unable to undergo cognitive testing 45 minutes after the infusion was stopped. In contrast, 10 minutes after the discontinuation of the infusion of propofol, all patients were awake, alert, cooperative, and able to undergo cognitive testing without difficulty. In conclusion, on examination of five non-randomly selected case records, we found that dexmedetomidine significantly prevented neurologic and cognitive testing.