The effect of gastroenterology training on the efficiency and cost of care provided to patients with diverticulitis.

BACKGROUND & AIMS: National trends emphasize the need for cost-efficient medical care with no diminution in quality. The most appropriate role for various physician groups has yet to be determined. The aim of this study was to investigate the efficiency of medical care provided by family practitioners (FPs), internists (IMs), and gastroenterologists (GIs) for acute diverticulitis. METHODS: All medicare hospitalizations from 1990 to 1993 in Illinois caused by acute diverticulitis, with FPs, IMs, or GIs as the primary attending physician, were included in the study. RESULTS: The primary attending physician was an FP in 1019 cases, an IM in 2535 cases, and a GI in 163 cases. The age and sex distributions were similar. The length of stay was significantly shorter (P < 0.0001) for GIs (7.4 +/- 6 days) than for FPs (7.9 +/- 14 days) or IMs (8.6 +/- 7 days). Readmission rate was significantly less (P < 0.03) for GIs (4.5%) than for FPs (7.7%) or IMs (10.0%). No significant differences were noted in complication rates or mortality. CONCLUSIONS: Patients with diverticulitis treated by GIs have a shorter hospital stay and a lower risk for readmission than patients treated by FPs or IMs. This improved quality of care should be considered by managed care organizations because they decide the role of various physician groups.

Mortality and length of stay as performance indicators for pneumonia in the elderly.

BACKGROUND: Mortality and length of stay are frequently used as performance measures for hospitals. If they are valid measures, they should be reproducible from year to year with attributable variation rather than random variation. METHODS: We compared hospitals on 2 outcomes, mortality and length of stay, in pneumonia in Medicare patients. The database was from 20 Illinois hospitals with the largest number of discharges for diagnosis-related group 89 (pneumonia with complications/comorbidities) for the years 1989 through 1992. This comprised 16,249 claims for hospitalization in patients 65 years of age or older. RESULTS: The distributions showed trends toward lower mortality and shorter stays over the 4 years. Correlation of performance from year to year at each hospital for mortality was low with none of the calculated correlation coefficients significant at p < .05. Correlations for length of stay were higher (all coefficients significant at p < .01). For length of stay, the correlation between 1991 and 1992 was .766 (p < .00005, r2 = .587), showing that nearly 60% of differences (variance) were caused by differences in performance. In contrast, for mortality in 1991 and 1992, the correlation was .301 (p = .0986, r2 = .091), showing that less than 10% of differences (variance) between hospitals were caused by differences in performance. Similar results were obtained when the 20 hospitals were ranked and their rank correlations calculated. CONCLUSION: For pneumonia in Medicare patients, differences in length of stay between hospitals are caused by differences in performance, while differences in mortality are random.

Rural hospital mortality for myocardial infarction in Medicare patients in Illinois.

OBJECTIVE: To compare rural and nonrural hospitals for mortality for Medicare patients with myocardial infarction. DESIGN: A retrospective analysis of variance from Illinois for the year 1989. Claims were aggregated by hospital and the hospitals grouped into geographic areas that were completely rural (N = 32), partially rural with small cities (N = 82), exurban (N = 21), suburban (N = 43), and urban (N = 44). PATIENTS: 11,753 patients older than 65 years hospitalized for acute myocardial infarction. RESULTS: In rural hospitals, the mean in-hospital mortality rate was 24.3% compared to rates of 18.3-20.9% at hospitals in the other four regions (P = 0.10, power = 0.68). Rates for coronary angiography were 0% at rural hospitals compared to 8-20% at hospitals in the other four regions (P < 0 0.0005, power = 0.99). CONCLUSION: There is a trend toward higher in-hospital mortality for myocardial infarction at rural hospitals. Whether this is caused by their inability to perform coronary angiography during the index admission warrants further investigation.

Secondary diagnoses as predictive factors for survival or mortality in Medicare patients with acute pneumonia.

We wished to determine if a claims-based method for severity adjustment would predict mortality or survival in pneumonia based on age, gender, and secondary diagnoses. We used a discriminant analysis model of severity of illness developed from Medicare Part A claims data. Our data base was taken from a hospitalized population age 65 years or older coded as DRG 89 (pneumonia with complications/comorbidities). There were 35,677 cases with a mortality = 11.2% in the derivation cohort from 1989 to 1990, and 19,915 cases with a mortality = 9.8% in the validation cohort from 1991. In the derivation cohort, 98% of patients predicted to live, lived, whereas 18% of patients predicted to die, died. Of the three variables, secondary diagnoses had greatest explanatory power. Receiver operating characteristic curves showed that the model performed best at 40% survival. Results were confirmed with the 1991 validation cohort. The model could be applied to hospitals with as few as 172 discharges. This simple, claims-based method can predict survival in pneumonia. It may be useful in selecting medical records for intensified review of medical quality.

Use of statistical control charts to assess outcomes of medical care: pneumonia in Medicare patients.

Detection of nonrandom variation in outcomes with statistical control charts is at the heart of quality improvement techniques. The authors examined the charts' ability to detect variations in outcome of pneumonia. They surveyed Medicare claims data for DRG 89, pneumonia with complications or co-morbidities, from November 1988 through October 1991 at 20 Illinois hospitals with the most Medicare discharges for DRG 89. Control charts were constructed on five outcomes--mean length of stay, range of length of stay, mortality, readmissions, and complications. Standard techniques from industrial statistics were used to construct the historical means and control limits derived from 2 years of data, to plot the monthly samples from the 3rd year of data and to score the control charts for nonrandom variation at less than 1% probability. The observed number of control charts with nonrandom variation was 33 of 100; the expected number was 9.18 (p < 0.0001). Nineteen hospitals had 1 to 3 control charts with nonrandom variation on the five outcomes, whereas only one hospital had none. The number of control charts with nonrandom variation per hospital did not correlate with hospital size, occupancy, teaching status, location, or payer-mix. Statistical control charts provide simple tools for identification of nonrandom variation in outcomes. To the extent that these variations can be related to quality issues, the charts will be useful for quality management.

Prenatal cocaine exposure alters postnatal ornithine decarboxylase activity in rabbit brain.

Ornithine decarboxylase, a modulator of tissue growth during fetal and neonatal mammalian development, serves as a sensitive marker enzyme for perturbations in neural development. To test the hypothesis that cocaine is a central nervous system neurodevelopmental teratogen through mechanisms involving direct cellular injury, we measured ornithine decarboxylase activity in brain sections of 4- to 6-day-old rabbit pups which were prenatally cocaine exposed and in pair-fed and free-fed controls. Rabbit does were implanted with the osmotic minipump prior to Gestational Day 10 and cocaine and/or sterile water was delivered between Gestational Days 10 and 32. The flow rate in the cocaine group was calculated to provide a daily cocaine dose of 30 mg/kg/day. Pups were sacrificed, brains were dissected into the cortex, pons, and medulla, and ornithine decarboxylase activity was measured. When compared to the pair-fed group, prenatal cocaine exposure significantly decreased ornithine decarboxylase activity in the cortex (0.531 +/- 0.070 nmol/g/h SEM vs 0.913 +/- 0.201 nmol/g/h SEM; cocaine vs pair fed, respectively; P < or = 0.05) and in the pons (0.533 +/- 0.036 nmol/g/h SEM vs 0.728 +/- 0.075 nmol/g/h SEM, cocaine vs pair fed, respectively; P < or = 0.05) but not in the medulla (0.374 +/- 0.040 nmol/g/h SEM vs. 0.392 +/- 0.045 nmol/g/h SEM, cocaine vs pair fed, respectively; P > 0.05). Although there were no statistically significant differences in ornithine decarboxylase activity between the cocaine-exposed group and the free-fed group in any brain region, all regions showed a relative decrease in ornithine decarboxylase activity with prenatal cocaine exposure.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of prenatal cocaine on the ventilatory response to hypoxia in newborn rabbits.

Recently, investigators have reported an alteration of postnatal respiratory pattern, deficient hypoxic arousal from sleep, and an increased incidence of sudden infant death syndrome (SIDS) among human infants exposed to cocaine prenatally, thus suggesting that prenatal cocaine exposure may perturb the maturation of respiratory control thereby increasing the risk for SIDS. To investigate the effects of prenatal cocaine on postnatal respiration, we evaluated the ventilatory response to 0.21 FIO2 (baseline) and at 0.15, 0.10, and 0.08 FIO2 by the barometric method on days 4-5 of life in 23 New Zealand White rabbit pups born to cocaine-exposed (30 mg/kg/day of cocaine HCl by continuous subcutaneous infusion), pair-fed and free-fed does. The chamber pressure deflection (proportional to VT after appropriate calculation) was computer-sampled at 200 Hz when the unanesthetized pups were resting quietly with no gross body movements. Recording was made after 10 min acclimatization to a specific FIO2. We found that baseline ventilation did not differ significantly among study groups. However, minute ventilation (VI), inspiratory flow (VT/TI), tidal volume (VT), increased significantly with hypoxia to peak values at 0.08 FIO2 in pair-fed and free-fed pups but these measurements did not increase significantly in cocaine-exposed pups. Our finding of a deficient second phase of the hypoxic ventilatory response among cocaine-exposed pups supports the hypothesis that prenatal cocaine perturbs the maturation of respiratory control.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of prenatal cocaine exposure on perinatal morbidity and postnatal growth in the rabbit.

Prenatal cocaine (CC) exposure may result in increased fetal loss, growth retardation, altered neurodevelopment, and sudden infant death syndrome (SIDS). We sought to establish an animal model for prenatal cocaine exposure which (1) would allow us to distinguish the direct effects from the indirect and nutritional effects of the drug, and (2) might be used to address questions of cocaine's toxicity, specifically to the developing respiratory control system. The study design included 38 New Zealand White rabbit does among CC, pair-fed (PF), and free-fed (FF) groups. Miniosmotic pumps were implanted in each doe on day 10 of timed gestation providing continuous subcutaneous administration of either 30 mg/kg/day of cocaine HCl in H2O (CC) or sterile H2O alone (PF and FF). Mean (SEM) plasma cocaine concentration was 1.71 +/- 0.21 mumol/l (519.4 +/- 64.4 ng/ml). Pregnancy outcome compared for incidence of stillbirth, maternal death, spontaneous abortion, and gross malformation among 211 pups was significant only for increased stillbirths among CC pups (18%, p less than 0.04) as compared to PF (6%) and FF pups (7%). External and renal malformation and postnatal weight, crown-rump length, and snout-occiput head circumference for pups aged 4 and 5 days of age did not differ among groups. The direct effects of prenatal cocaine evaluated in our model do not reproduce the altered perinatal outcome observed among humans. However, our results do not determine if physiologic function has been altered. Investigation of the physiologic and pathologic abnormalities that are relevant to this human condition, specifically to the developing respiratory control system, should add clarity to the mechanism of action of cocaine during pregnancy.

Effects of continuous low-frequency pacing on immature canine diaphragm.

Although diaphragm pacing has been shown to be a practical method of supporting ventilation in children, its usefulness has been limited because of concern that continuous (24 h/day) diaphragm pacing would fatigue and damage the diaphragm. We examined the functional and structural effects of continuous low-frequency diaphragm pacing on the left hemidiaphragm of five immature dogs aged 65 +/- 2 (SD) days at onset of pacing. Stimulus parameters approximated those required to pace infants: frequency 11.1 Hz, inspiratory time 810 ms, and respiratory rate 20 breaths/min. Animals were paced 24 h/day for 24-28 days. Paced tidal volumes and airway occlusion pressures were unchanged at low (less than 15 Hz) stimulus frequencies but were reduced at high (greater than 20 Hz) stimulus frequencies. Although histologically the paced hemidiaphragms appeared normal, histochemical studies showed a conversion from a mixture of type I (54%) and type II (46%) fibers to a uniform population of type I fibers with high oxidative enzyme activity. Transformation of muscle type was also demonstrated by pyrophosphate gel electrophoresis; fast and slow isomyosin bands were noted in control specimens, whereas only slow isomyosin was identified in paced specimens. Thus, in immature dogs, continuous low-frequency pacing affects both function and structure of the diaphragm.

Assessing validity of infant monitor alarms with event recording.

We evaluated the performance of an event recorder system in a large, consecutive series of referred monitored patients to determine the relative incidence of true apnea and true bradycardia, false alarms, and alarms for movement or a loose lead. In addition, we developed an event classification system based on the reason for the event being recorded. The recorder stored transthoracic impedance and electrocardiogram signals on a floppy disk before, during, and after each monitor alarm. These events on 302 disks from 83 patients were analyzed and classified as true, false, or movement-loose lead. Of 14,131 events, only 8% were caused by apnea or bradycardia (true events). Of true events, 70% were triggered by apnea and 30% by bradycardia. These true events occurred in 48% of the patients. False alarms constituted 23%, and movement-loose lead 69%, of all events. Even when movement-loose lead events were excluded, nearly three of four events were found to be false. Event recording proved helpful clinically, allowing discontinuation of the monitor in 49% of patients, modification of monitor alarm settings, or reassurance and counseling for parents.

Stimulus parameters for phrenic nerve pacing in infants and children.

Phrenic nerve pacing has been used since 1966 to support breathing in quadriplegics and patients with central hypoventilation syndrome (CHS). Recently, using low-frequency, long-inspiratory-time (Ti) stimulation, phrenic nerve pacing has been used successfully to support breathing 24 hours per day in adults and older children. However, no similar experience exists for infants and young children. Therefore, in 27 studies in 14 infants and children we determined the effects of changing Ti and interpulse interval (the inverse of stimulus frequency) on ventilation. Diaphragmatic action potentials, airflow, tidal volume, PACO2 and SaO2 were measured during sleep. Phrenic nerve pacing proved useful in 13 of 14 patients to support breathing either during wakefulness (n = 7) or during sleep (n = 6). We found that adequate ventilation could be achieved at significantly longer interpulse intervals, 95 +/- 25 (mean +/- SD) ms, and shorter Ti, 580 +/- 80 ms, than previously reported. At an average respiratory rate of 21 +/- 8 breaths/min it was thus possible to maintain adequate ventilation despite a marked reduction in the number of phrenic nerve stimuli. Theoretically, these reductions in phrenic nerve stimulation should minimize the chance of pacing-induced diaphragmatic damage. These results suggest that 24 hour per day phrenic nerve pacing may be a realistic goal in selected infants and children.