Preoperative Risk and the Association between Hypotension and Postoperative Acute Kidney Injury.

BACKGROUND: Despite the significant healthcare impact of acute kidney injury, little is known regarding prevention. Single-center data have implicated hypotension in developing postoperative acute kidney injury. The generalizability of this finding and the interaction between hypotension and baseline patient disease burden remain unknown. The authors sought to determine whether the association between intraoperative hypotension and acute kidney injury varies by preoperative risk. METHODS: Major noncardiac surgical procedures performed on adult patients across eight hospitals between 2008 and 2015 were reviewed. Derivation and validation cohorts were used, and cases were stratified into preoperative risk quartiles based upon comorbidities and surgical procedure. After preoperative risk stratification, associations between intraoperative hypotension and acute kidney injury were analyzed. Hypotension was defined as the lowest mean arterial pressure range achieved for more than 10 min; ranges were defined as absolute (mmHg) or relative (percentage of decrease from baseline). RESULTS: Among 138,021 cases reviewed, 12,431 (9.0%) developed postoperative acute kidney injury. Major risk factors included anemia, estimated glomerular filtration rate, surgery type, American Society of Anesthesiologists Physical Status, and expected anesthesia duration. Using such factors and others for risk stratification, patients with low baseline risk demonstrated no associations between intraoperative hypotension and acute kidney injury. Patients with medium risk demonstrated associations between severe-range intraoperative hypotension (mean arterial pressure less than 50 mmHg) and acute kidney injury (adjusted odds ratio, 2.62; 95% CI, 1.65 to 4.16 in validation cohort). In patients with the highest risk, mild hypotension ranges (mean arterial pressure 55 to 59 mmHg) were associated with acute kidney injury (adjusted odds ratio, 1.34; 95% CI, 1.16 to 1.56). Compared with absolute hypotension, relative hypotension demonstrated weak associations with acute kidney injury not replicable in the validation cohort. CONCLUSIONS: Adult patients undergoing noncardiac surgery demonstrate varying associations with distinct levels of hypotension when stratified by preoperative risk factors. Specific levels of absolute hypotension, but not relative hypotension, are an important independent risk factor for acute kidney injury.

Succinylcholine Use and Dantrolene Availability for Malignant Hyperthermia Treatment: Database Analyses and Systematic Review.

BACKGROUND: Although dantrolene effectively treats malignant hyperthermia (MH), discrepant recommendations exist concerning dantrolene availability. Whereas Malignant Hyperthermia Association of the United States guidelines state dantrolene must be available within 10 min of the decision to treat MH wherever volatile anesthetics or succinylcholine are administered, a Society for Ambulatory Anesthesia protocol permits Class B ambulatory facilities to stock succinylcholine for airway rescue without dantrolene. The authors investigated (1) succinylcholine use rates, including for airway rescue, in anesthetizing/sedating locations; (2) whether succinylcholine without volatile anesthetics triggers MH warranting dantrolene; and (3) the relationship between dantrolene administration and MH morbidity/mortality. METHODS: The authors performed focused analyses of the Multicenter Perioperative Outcomes Group (2005 through 2016), North American MH Registry (2013 through 2016), and Anesthesia Closed Claims Project (1970 through 2014) databases, as well as a systematic literature review (1987 through 2017). The authors used difficult mask ventilation (grades III and IV) as a surrogate for airway rescue. MH experts judged dantrolene treatment. For MH morbidity/mortality analyses, the authors included U.S. and Canadian cases that were fulminant or scored 20 or higher on the clinical grading scale and in which volatile anesthetics or succinylcholine were given. RESULTS: Among 6,368,356 queried outcomes cases, 246,904 (3.9%) received succinylcholine without volatile agents. Succinylcholine was used in 46% (n = 710) of grade IV mask ventilation cases (median dose, 100 mg, 1.2 mg/kg). Succinylcholine without volatile anesthetics triggered 24 MH cases, 13 requiring dantrolene. Among 310 anesthetic-triggered MH cases, morbidity was 20 to 37%. Treatment delay increased complications every 10 min, reaching 100% with a 50-min delay. Overall mortality was 1 to 10%; 15 U.S. patients died, including 4 after anesthetics in freestanding facilities. CONCLUSIONS: Providers use succinylcholine commonly, including during difficult mask ventilation. Succinylcholine administered without volatile anesthetics may trigger MH events requiring dantrolene. Delayed dantrolene treatment increases the likelihood of MH complications. The data reported herein support stocking dantrolene wherever succinylcholine or volatile anesthetics may be used.

Alarm Limits for Intraoperative Drug Infusions: A Report From the Multicenter Perioperative Outcomes Group.

BACKGROUND: Continuous medication infusions are commonly used during surgical procedures. Alarm settings for infusion pumps are considered important for patient safety, but limits are not created in a standardized manner from actual usage data. We estimated 90th and 95th percentile infusion rates from a national database for potential use as upper limit alarm settings. METHODS: We extracted infusion rate data from 17 major hospitals using intraoperative records provided by Multicenter Perioperative Outcomes Group for adult surgery between 2008 and 2014. Seven infusions were selected for study: propofol, remifentanil, dexmedetomidine, norepinephrine, phenylephrine, nitroglycerin, and esmolol. Each dosage entry for an infusion during a procedure was included. We estimated the 50th, 90th, and 95th percentile levels for each infusion across institutions, and performed quantile regression to examine factors that might affect the percentiles rates, such as use in general anesthesia versus sedation. RESULTS: The median 90th and 95th percentile infusion rates (with interquartile range) for propofol were 150 (140-150) and 170 (150-200) µg/kg/min. Quantile regression demonstrated higher 90th and 95th percentile rates during sedation for gastrointestinal endoscopy than for all surgical procedures performed under general anesthesia. For selected vasoactive medications, the corresponding median 90th and 95th percentile rates (with interquartile range) were norepinephrine 14.0 (9.8-18.1) and 18.3 (12.6-23.9) µg/min, and phenylephrine 60 (55-80) and 80 (75-100) µg/min. CONCLUSIONS: Alarm settings based on infusion rate percentile limits would be triggered at predictable rates; ie, the 95th percentile would be exceeded and an alarm sounded during 1 in 20 infusion rate entries. As a result, institutions could establish pump alarm settings consistent with desired alarm frequency using their own or externally validated usage data. Further study will be needed to determine the optimal percentile for infusion alarm settings.

Differences in intraoperative hemodynamics between spinal and general anesthesia in infants undergoing pyloromyotomy.

BACKGROUND: Hypotension and bradycardia are known side effects of spinal anesthesia in pregnant women undergoing cesarean section and adults undergoing other surgical procedures. Whether children experience similar hemodynamic changes is unclear. AIMS: The purpose of this study is to evaluate hemodynamic effects of spinal anesthesia compared to general anesthesia in a cohort of healthy infants. METHODS: The University of Vermont Medical Center almost exclusively used spinal anesthesia for infant pyloromyotomy surgery between 2008 and 2013, while Columbia University Medical Center relied on general anesthesia. The primary outcome assessed was the percentage change in intraoperative heart rate and blood pressure (systolic [SBP] and mean [MAP] blood pressure) from baseline. Analysis was performed using t-tests for continuous variables, followed by linear regression to account for differences in demographic and clinical covariates. RESULTS: The study sample consisted of 51 infants with spinal anesthesia at the University of Vermont and 52 infants with general anesthesia at Columbia University. The decrease from baseline for mean intraoperative SBP was -8.2 ± 16.8% for spinal anesthesia and -24.2 ± 17.2% for general anesthesia (difference between means: 16.2% [95% confidence interval (CI), 9.5-22.9]), while the decrease from baseline for mean intraoperative MAP was -16.3 ± 19.9% for spinal anesthesia and -24.6 ± 19.3% for general anesthesia (difference between means: 8.4% [95% CI, 0.8-16]). Spinal anesthesia patients also had smaller drops in minimum intraoperative MAP and SBP. These blood pressure differences persisted even after adjusting for covariates. No differences in heart rate were seen between spinal and general anesthesia. DISCUSSION: Our findings show that spinal anesthesia performed in healthy infants undergoing pyloromyotomy results in reduced intraoperative blood pressure changes from baseline, significantly higher blood pressure readings, and no increased bradycardia compared to general anesthesia. Further research is needed to assess whether any clinical impact of these hemodynamic differences between spinal and general anesthesia exists.

Attending Handoff Is Correlated with the Decision to Delay Extubation After Surgery.

BACKGROUND: Factors including ASA physical status, blood loss, and case length have been described as correlating with the decision to delay tracheal extubation after specific surgical procedures. In this retrospective study, we investigated whether handoffs by anesthesia attendings were associated with delayed extubation after general anesthesia for a broad range of surgical procedures. METHODS: We reviewed the records of 37,824 patients who underwent general anesthesia with an endotracheal tube for surgery (excluding tracheostomy surgery, cardiac surgeries, and liver and lung transplant surgeries) from 2008 to 2013 at Columbia University Medical Center. Our primary outcome was whether the patient was extubated at the end of the surgical case. We hypothesized that attending handoff was a factor that would independently affect the decision of the anesthesiologist to extubate at the end of the surgical case. In addition, we investigated whether the association between handoff and extubation was affected by the timing of the procedure (ending in the daytime versus evening hours) by including an interaction term in the analysis. We adjusted for other variables affecting the decision to delay extubation. RESULTS: Patients (5.4%, n = 2033) were not extubated in the operating room after the completion of their surgery. Cases with an attending handoff appeared to have a greater risk of delayed extubation with an adjusted risk ratio (aRR) of 1.14 (95% confidence interval [CI], 1.03-1.25). Further analysis demonstrated that the attending handoff had a significant effect in daytime cases (aRR, 1.62; 95% CI, 1.29-2.04) but not in evening cases (aRR, 1.07; 95% CI, 0.97-1.19). CONCLUSIONS: Attending handoff was an independent significant factor that increased the risk for the delay of extubation at the end of a surgical case.

Effect of atropine dose on heart rate during electroconvulsive therapy.

INTRODUCTION: Transient bradycardia during the stimulation phase of electroconvulsive therapy (ECT) is a well-known clinical observation. The optimal dose of atropine needed to prevent bradycardia has not been determined. This study was designed to investigate the effect of low doses of atropine on heart rate during ECT. METHODS: Patients who received at least 2 different doses of atropine over their series of right unilateral ECT were included in the analysis. The anesthetic consisted of 0, 0.2, 0.3, or 0.4 mg of atropine, methohexital, and succinylcholine. Heart rate was measured by the RR interval, the time between sequential R waves on the electrocardiogram. Analysis was performed using logistic multivariate regression and repeated-measures multivariate analysis of variance. RESULTS: One hundred eighteen ECT sessions were identified from 19 patients. Patients were grouped into 4 groups by atropine dose (0, 0.2, 0.3, or 0.4 mg) with 9, 33, 13, and 63 ECT sessions identified for each dose, respectively. Patients who received atropine had significantly less bradycardia after electrical stimulus and a faster heart rate through the seizure than patients who did not receive atropine. There was no significant difference in heart rate between patients receiving 0.2, 0.3, and 0.4 mg of atropine at any time point. There was no significant difference in heart rate at time points after the seizure conclusion in any group of patients. CONCLUSION: Low-dose atropine results in significantly less bradycardia after electrical stimulus. There was no significant difference in heart rate across low doses of atropine.

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.

Peripartum subarachnoid hemorrhage: nationwide data and institutional experience.

BACKGROUND: Subarachnoid hemorrhage (SAH) in pregnancy occurs because of a variety of etiologies, which range from ruptured aneurysms to benign venous bleeding. The more malignant etiologies represent an important cause of maternal morbidity and mortality. We sought to investigate the epidemiology and mechanisms of pregnancy-related SAH. METHODS: Using the Nationwide Inpatient Sample of the Healthcare Cost and Utilization Project, Agency for Healthcare Research and Quality, we extracted pregnancy-related admissions for women ages 15-44 from 1995-2008 and identified admissions complicated by SAH. Logistic regression identified independent predictors of SAH. Outcomes and risk factors were then compared with age-matched, nonpregnant women with SAH. We also analyzed our institution's experience with pregnancy-related SAH. RESULTS: There were 639 cases (5.8 per 100,000 deliveries) of pregnancy-related SAH in the cohort during the study period; SAH was associated with 4.1% of all pregnancy-related in-hospital deaths. More than half of the SAH cases occurred postpartum. Advancing age, African-American race, Hispanic ethnicity, hypertensive disorders, coagulopathy, tobacco, drug or alcohol abuse, intracranial venous thrombosis, sickle cell disease, and hypercoagulability were independent risk factors for pregnancy-related SAH. Compared with SAH in nonpregnant controls, pregnancy-related SAH had lower clipping/coiling rates (12.7% vs. 44.5%, P < 0.001). We identified 12 cases of pregnancy-related SAH in our hospital, the majority of which presented postpartum and with severe headache. CONCLUSION: SAH during pregnancy results from a range of etiologies, and is less likely to be because of a cerebral aneurysm than SAH occurring in the nonpregnant patient. Peripartum SAH frequently occurs in the setting of hypertensive disorders.

Technological advances in the management of unruptured intracranial aneurysms fail to improve outcome in New York state.

BACKGROUND AND PURPOSE: Unruptured intracranial aneurysms (UIAs) are being identified more frequently and endovascular coil embolization has become an increasingly popular treatment modality. Our study evaluates patient outcomes with changing patterns of treatment of UIA. METHODS: We conducted a retrospective, longitudinal cohort study of 3132 hospital discharges for UIA identified from the New York Statewide Database (SPARCS) in 2005 to 2007 and 2200 discharges from 1995 to 2000. The rates of endovascular coiling and surgical clipping were examined along with hospital variables and discharge outcome. Anatomic specifics of UIA were unavailable for analysis. RESULTS: The case rate for treatment of UIA doubled from 1.59 (1995 to 2000) to 3.45 per 100,000 (2005 to 2007, P<0.0001) and increased in the case treatment rate for coiling of UIA (0.36 versus 1.98 per 100,000, P<0.0001). Compared with the old epoch, there were more UIAs clipped at high-volume centers (55.8% versus 78.8%, P<0.0001) but fewer coiled at high-volume centers (94.8% versus 84.5%, P<0.0001) in the new epoch. Coiling and increasing hospital UIA treatment volume were associated with good discharge outcome. However, there was no significant improvement in overall good outcome when comparing 1995 to 2000 versus 2005 to 2007 (79% versus 81%, P=0.168) and a worsening of good outcomes for clipping (76.3% versus 71.7%, P=0.0132). CONCLUSIONS: Despite coiling being associated with an increased incidence of good outcome relative to clipping of UIA, the increase in coiling has failed to improve overall patient outcome. The shift in coiling venue from high-volume centers to low-volume centers and decreasing microsurgical volume accompanied by a worsening in microsurgical results contribute to this. This argues for greater centralization of care.

Radiation exposure of the anesthesiologist in the neurointerventional suite.

BACKGROUND: Scatter radiation during interventional radiology procedures can produce cataracts in participating medical personnel. Standard safety equipment for the radiologist includes eye protection. The typical configuration of fluoroscopy equipment directs radiation scatter away from the radiologist and toward the anesthesiologist. This study analyzed facial radiation exposure of the anesthesiologist during interventional neuroradiology procedures. METHODS: Radiation exposure to the forehead of the anesthesiologist and radiologist was measured during 31 adult neuroradiologic procedures involving the head or neck. Variables hypothesized to affect anesthesiologist exposure were recorded for each procedure. These included total radiation emitted by fluoroscopic equipment, radiologist exposure, number of pharmacologic interventions performed by the anesthesiologist, and other variables. RESULTS: Radiation exposure to the anesthesiologist's face averaged 6.5 ± 5.4 µSv per interventional procedure. This exposure was more than 6-fold greater (P < 0.0005) than for noninterventional angiographic procedures (1.0 ± 1.0) and averaged more than 3-fold the exposure of the radiologist (ratio, 3.2; 95% CI, 1.8-4.5). Multiple linear regression analysis showed that the exposure of the anesthesiologist was correlated with the number of pharmacologic interventions performed by the anesthesiologist and the total exposure of the radiologist. CONCLUSIONS: Current guidelines for occupational radiation exposure to the eye are undergoing review and are likely to be lowered below the current 100-150 mSv/yr limit. Anesthesiologists who spend significant time in neurointerventional radiology suites may have ocular radiation exposure approaching that of a radiologist. To ensure parity with safety standards adopted by radiologists, these anesthesiologists should wear protective eyewear.

Predicting Poor Outcome of COVID-19 Patients on the Day of Admission with the COVID-19 Score.

BACKGROUND: COVID-19 may result in multiorgan failure and death. Early detection of patients at risk may allow triage and more intense monitoring. The aim of this study was to develop a simple, objective admission score, based on laboratory tests, that identifies patients who are likely going to deteriorate. METHODS: This is a retrospective cohort study of all COVID-19 patients admitted to a tertiary academic medical center in New York City during the COVID-19 crisis in spring 2020. The primary combined endpoint included intubation, stage 3 acute kidney injury (AKI), or death. Laboratory tests available on admission in at least 70% of patients (and age) were included for univariate analysis. Tests that were statistically or clinically significant were then included in a multivariate binary logistic regression model using stepwise exclusion. 70% of all patients were used to train the model, and 30% were used as an internal validation cohort. The aim of this study was to develop and validate a model for COVID-19 severity based on biomarkers. RESULTS: Out of 2545 patients, 833 (32.7%) experienced the primary endpoint. 53 laboratory tests were analyzed, and of these, 47 tests (and age) were significantly different between patients with and without the endpoint. The final multivariate model included age, albumin, creatinine, C-reactive protein, and lactate dehydrogenase. The area under the ROC curve was 0.850 (CI [95%]: 0.813, 0.889), with a sensitivity of 0.800 and specificity of 0.761. The probability of experiencing the primary endpoint can be calculated as p=e (-2.4475+0.02492age - 0.6503albumin+0.81926creat+0.00388CRP+0.00143LDH)/1+e (-2.4475+ 0.02492age - 0.6503albumin+0.81926creat+0.00388CRP+0.00143LDH). CONCLUSIONS: Our study demonstrated that poor outcome in COVID-19 patients can be predicted with good sensitivity and specificity using a few laboratory tests. This is useful for identifying patients at risk during admission.

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.

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 > 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.

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.

Use of thrombolysis in acute ischemic stroke: analysis of the Nationwide Inpatient Sample 1999 to 2004.

STUDY OBJECTIVE: The aim of this study is to characterize hospital and patient characteristics associated with administration of thrombolysis in acute ischemic stroke patients in the United States. METHODS: This retrospective, observational, cohort study used data from the Nationwide Inpatient Sample, an administrative discharge database. A total of 366,194 hospitalizations admitted through the emergency department with a primary diagnosis of acute ischemic stroke were selected for analysis. The primary outcome considered in this study is whether the patient received thrombolytic therapy on hospital day 0 or 1. RESULTS: Thrombolysis was used in 1.12% (95% confidence interval [CI] 0.95% to 1.32%) of ischemic stroke hospitalizations. Most hospitals (69.5%; 95% CI 68.4% to 70.6%) treating ischemic stroke patients did not use thrombolysis during the study period. For the hospitals that used thrombolysis, the mean annual number of patients treated with thrombolysis per hospital was 3.06 (95% CI 2.68 to 3.44). In the binary logistic regression analysis, hospital characteristics associated with high use of thrombolysis were teaching hospital status and increasing number of stroke patients treated annually. Patient characteristics associated with higher use of thrombolysis were age younger than 55 years, male sex, and low comorbidity as measured by the modified Charlson Index; white race; and private self-pay health insurance. CONCLUSION: Use of thrombolysis for ischemic stroke in the United States from 1999 to 2004 was infrequent and showed significant differences, depending on hospital and patient demographic characteristics.

Factors associated with in-hospital mortality after administration of thrombolysis in acute ischemic stroke patients: an analysis of the nationwide inpatient sample 1999 to 2002.

BACKGROUND AND PURPOSE: The prospective trials evaluating the safety and efficacy of intravenous tissue plasminogen activator have generally been conducted at academic medical centers and community hospitals with an institutional commitment to stroke care. Relatively little is known about the safety of this therapy as it is used in the community. We therefore examined outcomes in acute stroke patients treated with thrombolysis using the largest discharge database available in the United States for the years 1999 to 2002. METHODS: Data were derived from the Nationwide Inpatient Sample for the years 1999 to 2002. Using the appropriate International Classification of Disease-Clinical Modification, 9th revision, codes, patients admitted through the emergency room with a primary diagnosis of acute ischemic stroke were selected for analysis. From these patients, those coded as receiving thrombolysis were identified. Multivariate logistic regression was performed on the thrombolysis and nonthrombolysis cohorts to identify independent predictors of in-hospital mortality from among those clinical elements available in the database. RESULTS: We identified 2594 patients treated with thrombolysis from a group of 248,964 patients admitted through the emergency room with a primary diagnosis of acute ischemic stroke. The thrombolysis cohort had a higher in-hospital mortality rate compared with the nonthrombolysis patients (11.4% versus 6.8%). The rate of intracerebral hemorrhage was 4.4% for the thrombolysis cohort and 0.4% for nonthrombolysis patients. Multivariate logistic regression showed advanced age, Asian/Pacific Islander race, congestive heart failure, and atrial fibrillation/flutter to be independent predictors of in-hospital mortality after thrombolysis. Thrombolysis volume, overall ischemic stroke volume, and teaching status were not significant predictors of in-hospital mortality after thrombolysis. CONCLUSIONS: Thrombolysis, as it is used in the community, has a safety profile that is similar to that observed in the large, prospective clinical trials.

Use of the Draeger Apollo to Deliver Bilevel Positive Pressure Ventilation During Awake Frontal Craniotomy for a Patient with Severe Chronic Obstructive Pulmonary Disease.

In this case report, we describe the use of the Draeger Apollo anesthesia machine to deliver bilevel positive airway pressure (BiPAP) to a patient with severe chronic obstructive pulmonary disease and a history of lung resection undergoing frontal craniotomy for the removal of a brain tumor under moderate to deep sedation. BiPAP in the perioperative period has been described for purposes of preoxygenation and postextubation recruitment. Although its utility as a mode of ventilation during moderate to deep sedation has been demonstrated, it has not come into widespread use. We describe the intraoperative use of pressure support mode on the anesthesia machine to deliver noninvasive positive pressure ventilation through a standard anesthesia mask. Given its ease of access and effectiveness, it is our belief that intraoperative BiPAP may reduce hypoxemia and/or hypercarbia in patients with chronic obstructive pulmonary disease and obstructive sleep apnea undergoing moderate to deep sedation.

Midazolam challenge reinduces neurological deficits after transient ischemic attack.

BACKGROUND AND PURPOSE: A transient ischemic attack (TIA) in the brain is classically considered a syndrome lasting <24 hours. Having previously shown that an experimental challenge with the GABAA agonist midazolam in recovered stroke patients can reinduce the acute clinical state, we determined whether TIA patients would demonstrate a similar effect. METHODS: Four right-handed patients participated: 3 with clinical TIA presumed to have affected the left hemisphere within the previous 24 to 72 hours and no evidence of a new lesion on diffusion-weighted and fluid-attenuated inversion recovery imaging, and 1 patient with an asymptomatic temporal arteriovenous malformation. The TIA duration ranged from 30 minutes to 3 hours. Each patient underwent baseline testing for motor function and aphasia, after which intravenous midazolam was delivered until mild drowsiness was detected. Patients were tested during the peak drug effect and again after 2 hours when sedation had dissipated. RESULTS: No patient showed weakness or aphasia at baseline. After administration of midazolam, all 3 TIA patients demonstrated re-emergence of features that characterized their recent transient neurological syndromes (right-sided weakness and/or aphasia) but no left-sided findings. The arteriovenous malformation patient who had never been symptomatic showed no drug effect. Two hours later, all TIA patients returned to their normal clinical state. CONCLUSIONS: Patients who had suffered recent transient cerebral ischemic episodes and were neurologically intact with negative diffusion-weighted imaging showed re-emergence of prior focal deficits after administration of a benzodiazepine in a dose that produces light sedation. These findings suggest that presumed TIA may produce neuronal dysfunction beyond the symptomatic period.

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.