An open-label randomized controlled clinical trial for comparison of continuous phenylephrine versus norepinephrine infusion in prevention of spinal hypotension during cesarean delivery.

BACKGROUND: During spinal anesthesia for cesarean delivery phenylephrine is the vasopressor of choice but can cause bradycardia. Norepinephrine has both ß- and α-adrenergic activity suitable for maintaining blood pressure with less bradycardia. We hypothesized that norepinephrine would be superior to phenylephrine, requiring fewer rescue bolus interventions to maintain blood pressure. METHODS: Eighty-five parturients having spinal anesthesia for elective cesarean delivery were randomized to Group P (phenylephrine 0.1µg/kg/min) or Group N (norepinephrine 0.05µg/kg/min) fixed-rate infusions. Rescue bolus interventions of phenylephrine 100µg for hypotension, or ephedrine 5mg for bradycardia with hypotension, were given as required to maintain systolic blood pressure. Maternal hemodynamic variables were measured non-invasively. RESULTS: There was no difference between groups in the proportion of patients who required rescue vasopressor boluses (Group P: 65.8% [n=25] vs. Group N: 48.8% [n=21], P=0.12). The proportion of patients who received ⩾1 bolus of phenylephrine was similar between groups (Group P: 52.6% [n=20] vs. Group N: 46.5% [n=20], P=0.58). However, more patients received ⩾1 bolus of ephedrine in the phenylephrine group (Group P: 23.7% [n=9] vs. Group N: 2.3% [n=1], P<0.01). The incidence of emesis was greater in the phenylephrine group (Group P: 26.3% vs. Group P: 16.3%, P<0.001). Hemodynamic parameters including heart rate, the incidence of bradycardia, blood pressure, cardiac output, cardiac index, stroke volume, and systemic vascular resistance and neonatal outcome were similar between groups (all P<0.05). CONCLUSION: Norepinephrine fixed-rate infusion has efficacy for preventing hypotension and can be considered as an alternative to phenylephrine.

Extended follow-up of an antibiotic cycling program for the management of febrile neutropenia in a hematologic malignancy and hematopoietic cell transplantation unit.

BACKGROUND: Febrile neutropenia is a common complication during treatment of hematological malignancies and hematopoietic cell transplantation. Empiric antibiotic therapy in this setting, while standard of care, commonly leads to microbial resistance. We have previously shown that cycling antibiotics in this patient population is feasible. This report provides long-term follow-up of cycling antibiotics in this patient population. METHODS: In a prospective cohort of hematological malignancy patients with neutropenic fever, we sought to evaluate the role of empiric antibiotic cycling in preventing antibiotic resistance. Antibiotic cycling was initiated in March 2002 and, until June 2005, antibiotics were cycled every 8 months (Cycling Period A). From July 2005 to December 2009, antibiotics were cycled every 3 months (Cycling Period B). The rates of bacteremia, resistance, and complications were compared to a retrospective cohort (Pre-cycling Period). RESULTS: The rate of gram-negative bacteremia decreased when compared to Cycling Periods A and B (5.3 vs. 2.1 and 3.3 episodes/1000 patient-days, respectively, P < 0.0001), most likely owing to implementation of quinolone prophylaxis. The resistance profile of the gram-negative organisms isolated remained stable over the 3 time periods, with the exception of an increase in quinolone resistance during the cycling periods. Gram-positive bacteremia rates remained stable, but vancomycin-resistant Enterococcus (VRE) increased significantly (0.1 vs. 1.0 and 1.6 episodes/1000 patient-days, respectively, P = 0.005) during cycling periods. Mortality rates were comparable. CONCLUSIONS: Antibiotic cycling for neutropenic fever was effectively implemented and followed over an extended time period. Gram-negative resistance remained stable, but there is some concern for selection of resistant gram-positive bacteria, specifically VRE. Although antibiotic cycling did not seem to cause resistance in our study, further study is necessary to clarify the effect of cycling on antibiotic resistance, patient outcomes, and hospital cost.

The clinical impact of antibacterial prophylaxis and cycling antibiotics for febrile neutropenia in a hematological malignancy and transplantation unit.

Febrile neutropenia is an expected complication during treatment of aggressive hematological malignancies and hematopoietic cell transplantation. We conducted a prospective cohort trial to determine the effects and safety of prophylactic fluoroquinolone administration, and rotation of empiric antibiotics for neutropenic fever in this patient population. From March 2002 through 2004, patients were treated with prophylactic levofloxacin during prolonged neutropenia, and a cycling schedule of empiric antibiotic therapy for neutropenic fever was initiated. The rates of bacteremia, resistance and complications were compared to a retrospective cohort of previously treated patients. The rate of gram-negative bacteremia decreased after the initiation of prophylactic levofloxacin (4.7 vs 1.8 episodes/1000 patient days, P<0.05). Gram-positive bacteremia rates remained unchanged, but more isolates of Enterococcus faecium were resistant to vancomycin after the intervention began. Resistance to the antibiotic agents used in the rotation did not emerge. There was no change in mortality during the intervention period. A prophylactic and cycling antibiotic schedule was successfully implemented on a hematological malignancy and hematopoietic cell transplant unit. gram-negative bacteremia was significantly decreased, without emergence of resistance. Concerns with Gram-positive resistance will require further observation.

The effect of asymmetry on psychophysical lifting capacity for three lifting types.

The effect of asymmetry on a person's lifting capacity was investigated using the psychophysical approach. Ten male college students lifted a box from pallet height (15 cm) to conveyor height (75 cm) at a frequency of one and five lifts/min. Three types of asymmetric lifting tasks (step-turn, middle twist and twist) were studied using 90 and 180 degrees task angles. Lifting capacity reductions for middle twist and twist at a 90 degrees asymmetric angle were about one-half of the 30% reduction that would be calculated by the 1991 National Institute for Occupational Safety & Health (NIOSH) lifting equation. The lifting capacity reduction for step-turn at 180 degrees was 14.9%, although that reduction cannot be calculated in the NIOSH equation. The middle twist lifting capacity was greatest among the three types at a 90 degrees task angle. The reductions for the middle twist and step-turn were not proportional to the task angle. This is contrary to the proportional reduction in the NIOSH lifting equation. Heart rate did not increase with an increase in task angle. Based on the results of this research, a different approach to assigning the asymmetric multiplier is proposed. This approach includes a task angle (as opposed to asymmetric angle) of up to 180 degrees.

Mediastinal lymph node sampling following positron emission tomography with fluorodeoxyglucose imaging in lung cancer staging.

OBJECTIVES: To evaluate the predictive accuracy as well as the rates of false-positive and false-negative results of CT and positron emission tomography (PET)-fluorodeoxyglucose (FDG) imaging in detecting the metastatic intrathoracic lymph nodes in patients with suspected or proven non-small cell lung cancer (NSCLC). Our other objective was to determine the need for routine invasive sampling procedure in confirming PET/CT staging results. METHODS: The results of CT and PET-FDG scanning in 77 patients with suspected or proven NSCLC were correlated with the histologic findings of hilar/mediastinal lymph node sampling using mediastinoscopy, open biopsy, thoracotomy, or thoracotomy with resection. Patients were then classified into resectable and unresectable groups based initially on PET results and compared to histologic findings. RESULTS: The sensitivity, specificity, and accuracy of CT and PET for detecting metastatic lymphadenopathy were 68%, 61%, 63%, and 87%, 91%, and 82%, respectively. A change of management with routine sampling following PET was seen in five of six patients (83%) with false-positive findings (13%) but in none of four patients (9%) with false-negative findings. CONCLUSION: The false-positive findings of PET-FDG imaging affected selection of treatment in 83% of patients. However, false-negative results did not change management in any patient. This could potentially prevent unnecessary invasive thoracotomy, mediastinoscopy, or other sampling procedures in patients with negative PET results.

Data mining and healthcare informatics.

OBJECTIVE: To acquaint members of the Academy with a relatively recent development in the area of data exploration and statistical analysis. METHODS: A review of the concepts and methods inherent in data-mining with a special emphasis on the those methods applicable to predictive modeling. RESULTS: Data-mining is demonstrated to be a useful tool for researchers in those circumstances where large amounts of information are available. CONCLUSIONS: With the advent and proliferation of on-line data collection, truly massive databases are now available to health care researchers. In that situation, data-mining methods yield some unique opportunities to researchers who wish to develop prediction models and to establish associations.

Redistribution of sudomotor responses is an early sign of sympathetic dysfunction in type 1 diabetes.

Patients with diabetic neuropathy typically have decreased sweating in the feet but excessive sweating in the upper body. Previous studies of sudomotor function in diabetes have included patients with longstanding disease. The present study was designed to test for the early presence of sudomotor dysfunction and to characterize its relation to glycemic control and other aspects of peripheral nerve function. A total of 37 patients (10 males, 27 females) enrolled in a longitudinal study, in which autonomic function was evaluated annually for 3 years. Patients enrolled 2-22 months after the diagnosis of type 1 diabetes. Forty-one age- and sex-matched healthy control subjects were also studied. Sweat production in response to acetylcholine stimulation was dramatically increased in the forearm at the time of the first evaluation (1.67 +/- 0.24 micro/cm2 in the diabetic patients vs. 1.04 +/- 0.14 microl/cm2 in the control subjects, P < 0.05). Likewise, the ratio of sweating in the forearm to sweating below the waist was higher in the diabetic patients (0.553 +/- 0.07 microl/cm2) than in the control subjects (0.385 +/- 0.04 microl/cm2, P < 0.05). Forearm sweat was negatively associated with the renin-toprorenin ratio and vanillylmandelic acid (VMA) excretion (P < 0.025), tests of sympathetic nerve function. The ratio of sweating in the forearm to sweating in the foot was likewise increased in diabetic patients with poor glycemic control. We interpret this redistribution of sudomotor responses to be indicative of sympathetic nerve injury and conclude 1) that the sympathetic nervous system is especially vulnerable to the adverse effects of chronic hyperglycemia and 2) that sympathetic dysfunction can be detected very early in type 1 diabetes.

The effect of a hospitalist service with nurse discharge planner on patient care in an academic teaching hospital.

PURPOSE: To evaluate the impact of implementing a hospitalist service with a nurse discharge planner in an academic teaching hospital. SUBJECTS AND METHODS: Inpatient medicine service was provided by hospitalists, general internists, and specialists. Service personnel were identical except that the hospitalist service also had a nurse discharge planner. Hospitalists attended 4 months per year (compared with the 1 month by most other attending physicians) and had no outpatient responsibilities during the ward months. Patients were admitted alternately based on resident call schedule. Major outcomes included average costs of hospitalization, length of stay, and resource utilization. Quality measures included inpatient mortality, 30-day readmission rates, and satisfaction of patients, residents and students. RESULTS: Hospitalist-attended services had lower mean (+/- SD) inpatient costs per patient ($4289 +/- $6512) compared with specialist-staffed services ($6066 +/- $7550, P < 0.0001), with a trend toward lower costs when compared with generalist-attended services ($4850 +/- $7027, P = 0.11). Hospitalist services had shorter mean lengths of stay (4.4 +/- 4.0 days), compared with generalists (5.2 +/- 5.2 days) and specialists (6.0 +/- 5.5 days, P < 0.0001 for hospitalists vs. both groups). Readmission rates were similar in all groups. Mortality rates were higher in the specialist group [5.0% (44 of 874)] compared with hospitalists [2.2% (18 of 829)] and generalists [2.6% (20 of 761), P = 0.002 for specialists vs. both groups, P = 0.09 for generalists vs hospitalists]. Satisfaction results were uniformly high in all groups, with no significant differences. CONCLUSION: Hospitalist services with a nurse discharge planner were associated with lower average cost and shorter average length of hospital stay, without any apparent compromise in clinical outcomes or patient satisfaction.

Creutzfeldt-Jakob disease and blood transfusions: a meta-analysis of case-control studies.

A meta-analysis of five published case-control studies that examined the association between previous blood transfusions and Creutzfeld-Jakob disease was performed. The results demonstrated that controls were more likely (p < 0.001, odds ratio = 1.56, 95% confidence interval, 1.22-1.98) to have received previous blood transfusions (18.7%) than Creutzfeld-Jakob disease patients (12.9%), suggesting that selection bias of the control populations had occurred.

Antibodies to glutamic acid decarboxylase and peripheral nerve function in type 1 diabetes.

Autoimmune mechanisms have been implicated in the pathophysiology of diabetic neuropathy. We studied the association between glutamic acid decarboxylase (GAD65) and islet cell (IA-2) autoantibodies as well as autoantibodies to the autonomic nervous system and peripheral nerve function in recent onset type 1 diabetes. Thirty-seven patients (27 females and 10 males) enrolled 2-22 months after diagnosis. Humoral factors, glycemic control, and peripheral nerve function were measured annually for 3 yr. Patients with high GAD65Ab had worse glycemic control and higher insulin requirements. Patients with high GAD65Ab had slower motor nerve conduction velocities in the median, ulnar, and peroneal nerves (P < 0.025 for each nerve). The mean motor nerve conduction velocity Z scores at the time of the third evaluation was 0.341 +/- 0.25 for the low GAD65Ab patients and -0.600 +/- 0.25 for the high GAD65Ab patients (P < 0.01). Similar differences between the low and high GAD65Ab groups were observed for F wave latencies, thermal threshold detection, and cardiovascular autonomic function. The composite peripheral nerve function Z scores in the low GAD65Ab patients were 0.62 +/- 11, 0.71 +/- 0.19, and 0.21 +/- 0.14 at the first, second, and third evaluations, significantly different from those in the high GAD65Ab patients in whom they were -0.35 +/- 0.15, -0.46 +/- 0.18, and -0.42 +/- 0.16 (P < 0.001). In summary, GAD65Ab in patients with recent onset type 1 diabetes are associated with worse glycemic control and slightly worse peripheral nerve function. Although the latter remained within normal limits and none of the patients had clinical neuropathy, the GAD65Ab-related differences in composite peripheral nerve function were highly significant (P < 0.001) and could not be attributed to GAD65Ab-related differences in glycemic control.

Psychophysical assessment of assistive devices for transferring patients/residents.

This article reports the psychophysical assessment of nine battery-powered lifts, a sliding board, a walking belt, and a baseline manual method for transferring nursing home patients/residents from a bed to a chair. A separate article reports the biomechanical evaluation of the same task and devices. The objectives of the psychophysical assessment were to investigate the effects of resident-transferring methods on the psychophysical stress to nursing assistants performing the transferring task, and to identify transfer methods that could reduce the psychophysical stress reported by nursing assistants. Nine nursing assistants served as test subjects. Two elderly persons participated as residents. The results indicated that the psychophysical stresses on nursing assistants were significantly lower when performing resident transfers with some of the assistive devices than when performing transfers with the baseline manual transfer method. The nursing assistants generally preferred the basket-sling lift and stand-up lift to other methods. The residents' comfort and security ratings indicated the comfort and security with most of the assistive devices were greater than or equal to the baseline manual method. Most of the comments of the nursing assistants and residents on the assistive devices were favourable.

Decreased prorenin processing develops before autonomic dysfunction in type 1 diabetes.

It is well documented that diabetic patients with chronic complications have decreased renin secretion and elevations in the renin precursor prorenin. It is uncertain, however, whether the abnormal processing of prorenin is reflective of microvascular disease, hypertension, or autonomic neuropathy. Dechaux et al. (Transplant Proc. 18:1598-1599, 1986) observed abnormalities in prorenin processing in uncomplicated diabetes and suggested that it was the result of subclinical autonomic neuropathy. To test this hypothesis, we measured renin, prorenin, and autonomic function in early type 1 diabetes at a time when there is little or no microvascular disease or hypervolemia. Thirty-seven patients (10 males, 27 females) enrolled 2-22 months after diagnosis in a longitudinal study in which renin, prorenin, and autonomic function were measured annually for 3 years. Forty-one age-matched control subjects were also studied. PRA in the diabetic patients at the time of the second and third evaluations was 1.71 +/- 0.24 ng angiotensin I/mL x h and 1.67 +/- 0.24 ng angiotensin I/mL x h, respectively, significantly lower (P < 0.05) than that of the control subjects in whom PRA was 2.96 +/- 0.38 ng angiotensin I/mL x h. Prorenin was not different in the diabetic patients in comparison with controls. The renin to prorenin ratio in the diabetic patients at the time of the first, second, and third evaluations was 0.260 +/- 0.03, 0.235 +/- 0.05, and 0.227 0.05, respectively, significantly lower (P < 0.01) than in control subjects in whom the renin to prorenin ratio was 0.475 +/- 0.08. Despite this, at the time of the first and second evaluations, there was no evidence of autonomic dysfunction and no correlation between any test of autonomic function and the renin to prorenin ratio. At the time of the third evaluation, however, the intermediate frequency (0.04-0.15 Hz) power spectra while patients were supine (an index of sympathetic modulation of heart rate variability) showed a highly significant (P < .001) correlation with the renin to prorenin ratio. High frequency (0.15-0.40 Hz) spectra from supine patients at the third evaluation also correlated with the renin to prorenin ratio (P < 0.01). We conclude abnormal processing of prorenin develops in diabetic patients prior to microvascular disease, even before the first evidence of autonomic dysfunction. Although the latter may play a contributory role, additional as yet unidentified mechanisms seem to interrupt the processing of prorenin in early diabetes.

Prophylactic antibiotics with intracranial pressure monitors and external ventricular drains: a review of the evidence.

BACKGROUND: The role of prophylactic antibiotics (PABs) in preventing infections associated with intracranial pressure (ICP) monitors and external ventricular drains (EVD) is not well defined. METHODS: This study includes an analysis of published reports and a survey of current practices regarding the use of PABs with ICP monitors and EVDs. A computerized data search and a review of the abstracts from two major national neurosurgical meetings over the past decade yielded 85 related articles. Three independent investigators, blinded to the title, author(s), institution(s), results, and conclusions of the articles used predetermined inclusion criteria to select studies for meta-analysis. Thirty-six responses were returned from 98 questionnaires (37%) mailed to university neurosurgical programs. RESULTS: Among the articles reviewed, only two studies met the predetermined inclusion criteria for the meta-analysis, and they were of insufficient size to produce statistically significant results. Among the 36 programs that responded to the survey, 26 (72%) used PABs, mainly cephalosporins (46%) and semisynthetic penicillins (38%), with ICP monitors and EVDs. Twenty-two (85%) used one drug, and 4 (15%) used two drugs. Twenty-two (61%) of the total group reported intra-institutional variation in practices among individual staff neurosurgeons. Nineteen (53%) expressed interest in a retrospective study, and 27 (75%) expressed interest in a prospective study on the role of PABs in minor neurosurgical procedures. CONCLUSION: No consensus regarding the use of PABs with ICP monitors and EVDs is noted. Randomized controlled trials of sufficiently large size with appropriate blinding are needed to address this issue.

Neonatal suck reflex pattern does not predict apnea.

Respiration and suck are gestational age-dependent reflexes modulated in the brain stem. To determine if the suck reflex pattern could be used to predict apnea, the relationship between the two was examined in 28 neonates. The suck reflex was quantified with respect to burst-pause rhythm, amplitude of negative suck pressure, and synchrony of the negative-positive pressure. Apneas were counted 5 days prior to and following measurement of the suck reflex pattern. Increasing gestational age correlated with a lower frequency of apnea (P < .01) and higher suck scores (P < .01). A mature suck reflex pattern, however, failed to predict the occurrence of apnea.

Biomechanical evaluation of assistive devices for transferring residents.

This is the first of two articles to report a biomechanical evaluation and psychophysical assessment of nine battery-powered lifts, a sliding board, a walking belt, and a baseline manual method for transferring nursing home residents from a bed to a chair. The objectives of the biomechanical evaluation were: (1) to investigate the effects of transfer method and resident weight on the biomechanical stress to nursing assistants performing the transferring task, and (2) to identify resident-transferring methods that could reduce the biomechanical stress to the nursing assistants. Nine nursing assistants served as test subjects; two elderly persons participated as residents. A four-camera motion analysis system, two force platforms, and a three-dimensional biomechanical model were used to measure biomechanical load. The results indicate that transfer method and resident weight affect a nursing assistant's low-back loading. The basket-sling and overhead lift devices significantly reduced the nursing assistants' back-compressive forces during the preparation phase of a resident transfer. In addition, the use of basket-sling, overhead, and stand-up lifts removed about two-thirds of the exposure to low-back stress (lifting activities per transfer) as compared to the baseline manual method. Thus, the use of these devices reduces biomechanical stress, and thereby will decrease the occurrence of resident-handling-related low-back injuries. Furthermore, lifting device maneuvering forces were found to be significantly different and a number of design/use problems were identified with various assistive devices. The second article will detail the psychophysical assessment of the same resident-transferring methods.

An estimate of prostate cancer prevalence for a demographically similar workforce population.

To obtain an estimate of prostate cancer prevalence when screening is applied to a workforce, we conducted a search of the English world literature from West Virginia University. Thirty-one papers which met selection criteria for screening were followed by histopathologic diagnosis. Publications using Prostate Specific Antigen (PSA) as a screening test were reviewed. The data from these papers were combined. Population characteristics were then selected to represent the demographics of a working population. Prostate cancer prevalence estimates for the demographics of a working population were calculated using a weighted mean after relevant studies lacked homogeneity and therefore failed meta-analysis. The expected prevalence of prostate cancer in a workplace surveillance population is 2.03% (95% C.I. from 1.69% to 2.37%). This information is useful to entities considering workplace surveillance. Selection bias, geographic location, and uncertainty in prediction of a representative workforce population may strongly influence estimates.

Neonatal seizures: incidence, onset, and etiology by gestational age.

OBJECTIVE: To examine the influence of gestational age on seizures in the neonatal intensive care unit. STUDY DESIGN: A cohort of 4165 neonates admitted to a university intensive care unit between 1986 and 1995. The incidence, time of onset, and etiology of neonatal seizures in the cohort were distributed by gestational age. Logistic regression and t test were used to examine the relationship between gestational age and seizures in the neonatal intensive care unit. RESULTS: Seizures occurred in 356 (8.6%) infants. The seizure rate was parabolically related to gestational age, such that infants at 30 to 36 weeks' gestation had a 4.8% rate compared with 11.9% and 14.1% rates for infants < 30 and > 36 weeks, respectively (p < 0.001). Seizures manifested earlier in infants < 30 weeks (2.3 +/- 5.6 days of life) and > 36 weeks (3.7 +/- 8.7 days) gestational age compared with neonates 30 to 36 weeks (10.4 +/- 14.5 days) (p < 0.001). Intraventricular hemorrhage was the principal etiology underlying the higher seizure rate for infants < 30 weeks (p < 0.001). Hypoxic-ischemic encephalopathy and congenital malformations were primary factors for infants > 36 weeks (p < 0.01). Nervous system infections were evenly distributed across gestational age. CONCLUSION: Gestational age exerts a considerable influence on the incidence, onset, and etiology of neonatal seizures.

The acute pressure natriuresis response blunted and the blood pressure response reset in the normal pregnant rat.

OBJECTIVES: Our purpose was to test the hypothesis that the acute pressure natriuresis curve was reset in pregnancy to facilitate the volume expansion. STUDY DESIGN: Studies were done with 14- to 16-day pregnant (n = 8) and age-matched virgin female (n = 6) Sprague-Dawley rats that were under general anesthesia. The left kidney was denervated, and mechanical clamps were placed on the aorta above and below the renal arteries for manipulation of renal perfusion pressure. Rats received intravenous 0.9% sodium chloride (1.5% body weight/h) and a cocktail of vasoactive factors to suppress variation in endogenous hormones. Renal perfusion pressure was varied acutely from 125 to 95 mm Hg, and glomerular filtration rate, renal plasma flow, sodium excretion, and urine flow were measured in both kidneys at each renal perfusion pressure. Data were analyzed by unpaired t test and by homogeneity by slopes. RESULTS: The acute pressure natriuresis curve was blunted in pregnant rats versus virgins, and the renal nerves were not responsible. The blunted natriuretic response in pregnancy was due to loss of tubular epithelial responsiveness to increased blood pressure. CONCLUSION: The pressure natriuretic response is markedly blunted in pregnancy, permitting the cumulative plasma volume expansion to occur. Contrary to nongravid states, blunting of the acute pressure natriuresis curve in pregnancy is not associated with increased blood pressure because of the profound peripheral vasodilation. This suggests an alteration in the mechanism(s) normally linking blood pressure control to the acute pressure natriuresis relationship.