Search PubMed⌕ Search

Biomedical subjects

A D Bersten

Publications and source records attributed to A D Bersten.

At least 37 records · Page 2Linked to original sources
PubMed1998

The use of antimicrobials in ten Australian and New Zealand intensive care units. The Australian and New Zealand Intensive Care Multicentre Studies Group Investigators.

A prospective standardized collection of clinical, microbiological and pharmaceutical information on antibiotic use was conducted in Australia and New Zealand intensive care units (ICUs) involving 481 consecutive critically ill patients who were receiving antibiotics for any reason while in ICU. Patients had a mean SAPS II score of 34.1 +/- 17.8 with an expected mortality of 15.6% (actual mortality 12%). Of these, 292 (60.8%) were admitted to the ICU within 72 hours of surgery. Among such surgical patients, 233 (79.9%) received antibiotics for "surgical prophylaxis" while in ICU (48% of sample population). The second largest group of patients treated with antibiotics in ICU included those with systemic inflammatory response syndrome and clinical suspicion of infection (38%). Antibiotics were prescribed for the treatment of clinically diagnosed infection in 268 patients. Clinical response was apparent in 62.6% and in most (71%) was achieved in the first 72 hours of treatment. The incidence of antimicrobial-related side-effects was 4%, mostly in the form of diarrhoea or rash (75% of all side-effects). The most commonly prescribed antimicrobials were gentamicin (n = 146), ceftriaxone (n = 98), vancomycin (n = 94) and metronidazole (n = 111). Three times daily prescription of aminoglycosides was uncommon (< 1%). Forty-one patients had a documented infection (positive culture) with a gram-negative organism. Of these, 17 received therapy with a single antibiotic and 24 received therapy with two antibiotics. Despite similar illness severity, there were six deaths in the former group and only two in the latter.

Anti-Bacterial Agents↗
PubMed1998

Surfactant composition reflects lung overinflation and arterial oxygenation in patients with acute lung injury.

Pulmonary surfactant abnormalities have consistently been documented in patients with acute lung injury (ALI), however, there is little evidence directly correlating them to altered respiratory mechanics. To explore this further, surfactant composition was measured in lung aspirate fluid collected on 15 occasions from 10 patients with ALI. The composition was compared with lung aspirate fluid from 11 intubated patients prior to elective cardiac surgery (CS), and bronchoalveolar lavage fluid from 16 normal subjects. In both the ALI and cardiac groups the proportion of disaturated phospholipids (DSP) and phosphatidylcholine was reduced. Plasma levels of surfactant proteins-A and -B (SP-A and -B) were elevated, but were unrelated to alveolar surfactant levels. In the ALI group, and the ALI + CS group, DSP, normalized to the total phospholipid content, sphingomyelin (SPH), and urea, showed strong direct correlations with arterial oxygen tension/inspiratory oxygen fraction (all p < or = 0.01). In the ALI group, normalized DSP was also directly related to the elastance of the positive end-expiratory pressure-induced increase in the end-expiratory lung volume (all p < or = 0.02), and indirect correlations were found with a measure of lung overinflation (%E2; all p < or = 0.01). We conclude that surfactant composition correlates with lung function abnormalities in acute lung injury and cardiac patients, and that both groups had elevated plasma surfactant proteins-A and -B levels, consistent with a concurrent increase in alveolocapillary permeability.

Blood-Air Barrier↗
PubMed1998

Measurement of overinflation by multiple linear regression analysis in patients with acute lung injury.

Strategies to optimize alveolar recruitment and prevent lung overinflation are central to ventilatory management of patients with acute lung injury (ALI). The recent description of overinflation using multilinear regression analysis of airway pressure (Paw) and flow (V') data allows a functional assessment of lung mechanics. However, this technique has not been studied in ALI patients. During 15 positive end-expiratory pressure (PEEP) trials in 10 ALI patients, respiratory elastance was partitioned into volume-independent (E1) and volume-dependent (E2VT) components, where Paw=(E1+E2VT)V+RrsV'+Po; where V is volume, VT is tidal volume, Rrs is respiratory resistance and Po is static recoil pressure at end-expiration (equivalent to total PEEP). Then, %E2 was calculated as (100E2VT)/(E1+E2VT); a measure of lung overinflation when %E2>30%. Alveolar recruitment, assessed as a PEEP-induced increase in V>50 mL at a constant Paw occurred in 14 of 15 trials (299+/-34 mL, mean+/-SEM), but was independent of the degree of lung inflation. Lung overinflation was common (six of 15 clinically set PEEP levels) and occurred despite a dynamic elastic distending pressure (Pel,dyn) <30 cmH2O during 18 of 36 PEEP titrations. During a PEEP titration the resultant %E2 was directly related to delta(peak airway pressure-Po) (rs=0.86, p<0.001) and delta(Pel,dyn-Po) (rs=0.89, p<0.001). The 95% predictive intervals for a 2 cmH2O change in either driving pressure were %E2 values of 30.4-68.1% and 32.8-69.2%, respectively. Single or continuous measurement of %E2 (a measure of lung inflation) is a readily available method for titrating ventilatory parameters. Further, during a positive end-expiratory pressure titration a change in ventilatory driving pressure > or =2 cmH2O is indicative of overinflation.

Acute Disease↗
PubMed1997

Endotoxin alters the systemic disposition of nitric oxide synthase inhibitors in the awake sheep.

1. We evaluated the haemodynamic effects and systemic disposition of the nitric oxide synthase (NOS) inhibitor NL-nitro-L-arginine (NOLA) after intravenous (i.v.) administration of two different doses (5 and 20 mg/kg) in awake healthy sheep and awake sheep given a continuous i.v. infusion of endotoxin (lipopolysaccharide, 12 ng/kg per h, i.v., for 18 h). In addition, we determined the systemic disposition of another NOS inhibitor, NL-nitro-L-arginine methylester (L-NAME; 20 mg/kg, i.v.) in awake healthy sheep only. 2. NL-Nitro-L-arginine produced a dose-dependent decrease in heart rate (HR) and cardiac output (CO) together with a dose-dependent increase in mean arterial pressure (MAP) and peripheral vascular resistance (PVR) when compared to baseline. In endotoxic sheep NOLA produced a greater increase in MAP and mean pulmonary arterial pressure (MPAP). 3. In healthy sheep there was a dose-related increase in total body clearance (Cl) of NOLA. The Cl increased from 0.028 L/min after the lower dose to 0.032 L/min after the higher dose. The infusion of endotoxin caused an increase in Cl of NOLA to 0.040 and 0.047 L/min, respectively, and a decrease in plasma slow half-life (t1/2) from 825 to 546 min and from 780 to 453 min, respectively. 4. NL-Nitro-L-arginine methylester was rapidly cleared from the plasma with a slow half-life of approximately 7.5 min and there was a simultaneous appearance of NOLA in the plasma. 5. These results support the view that nitric oxide has a significant role in regulating vascular tone in healthy and endotoxic sheep and indicate that the increases in Cl of NOLA with an increase in its dose and the presence of endotoxin will be important in influencing appropriate dosage regimens in clinical studies.

Animals↗
PubMed1997

Aerosol kinetics and bronchodilator efficacy during continuous positive airway pressure delivered by face mask.

BACKGROUND: Rates of fresh gas flow (FGF) commonly used when continuous positive airway pressure (CPAP) is delivered by face mask theoretically reduce the delivery and availability of therapeutic aerosols. As it may be hazardous for patients with acute respiratory failure to interrupt mask CPAP, the effects of CPAP on aerosol kinetics and bronchodilator efficacy were investigated. METHOD: The effect of CPAP at 10 cm H2O at a FGF rate of 50 l/min on the delivery of technetium labelled aerosol generated from a readily available jet nebuliser was measured using a bench model of spontaneous respiration. In a separate clinical study the bronchodilator responses to incremental doses of nebulised salbutamol were measured in nine stable asthmatic subjects in a random sequence of conventional nebulisation (control) or nebulisation whilst receiving CPAP via a tight fitting face mask. Each patient acted as his or her own control. RESULTS: CPAP significantly reduced total aerosol delivery to the face mask from 6.85 (1.52)% to 1.3 (0.37)% of the initial nebuliser charge. In the clinical study a significant bronchodilator response to nebulised salbutamol was seen during both conventional nebulisation and nebulisation whilst receiving CPAP by face mask. The shape of the dose-response curves and the magnitude of the total increase in the forced expiratory volume in one second (FEV1) was identical for CPAP and control conditions. CONCLUSIONS: Despite a reduction in aerosol presented to the proximal airway, the bronchodilator response to inhaled beta 2 agonists in stable asthmatic subjects was not affected when CPAP was delivered by face mask. Despite a high rate of FGF, nebulised beta 2 agonists are effective when administered in conjunction with CPAP delivered by face mask.

Adult↗
PubMed1997

Surfactant replacement therapy in ARDS: white knight or noise in the system?

Although one would predict that surfactant replacement therapy would be effective in acute respiratory distress syndrome (ARDS), a recent large trial proved unsuccessful, possibly reflecting the nature of the surfactant used. Given the importance of the unique proteins in the action of surfactant, these would seem vital components of any exogenous surfactant. The ability to identify patients at risk of ARDS and to characterise their surfactant might allow prophylactic treatment with a nebulised, complementary, tailor-made preparation of surfactant. Advanced cases might undergo bronchoscopic focal lavage to remove plasma proteins and inflammatory mediators prior to focal instillation of surfactant to areas of greatest need. Ventilation regimens might be adjusted both to minimise trauma and to conserve endogenous surfactant.

Adult↗
PubMed1997

Surfactant proteins-A and -B are elevated in plasma of patients with acute respiratory failure.

Surfactant protein-A (SP-A) leaks into the circulation of patients with acute respiratory distress syndrome (ARDS) or acute cardiogenic pulmonary edema (APE) in a manner inversely related to lung function. Since surfactant protein-B (SP-B) is synthesized as a precursor considerably smaller than alveolar SP-A, we investigated whether it enters the circulation more readily. Reactivities consistent with SP-B proprotein (approximately 42 to approximately 45 kD) and the approximately 25 kD processing intermediate were detected in plasma. Plasma immunoreactive SP-B levels were significantly higher in ARDS (8,007+/-1,654 ng/ml [mean+/-SEM], n = 22) and APE (3,646+/-635 ng/ml, n = 10) patients compared with normal subjects (1,685+/-58 ng/ml, n = 33) and ventilated patients with no cardiorespiratory disease (1,829+/-184 ng/ml, n = 7). All groups had plasma SP-B/SP-A ratios approximately 6- to approximately 8-fold higher than in normal lavage or ARDS tracheal aspirate fluid, consistent with protein sieving. During admission, both plasma SP-B and the SP-B/SP-A ratio were inversely related to blood oxygenation (PaO2/FIO2) (p < 0.0001 and p < 0.025, n = 260 from 39 patients; Spearman) and static respiratory system compliance (deltaV/deltaP) (p < 0.0001 and p < 0.01, n = 168 from 25 patients). We describe in detail three patients and conclude that immunoreactive SP-B enters more readily than SP-A, is cleared acutely, and provides a better indicator of lung trauma.

Acute Disease↗
PubMed1996

Continuous renal replacement therapy in critically ill patients: monitoring circuit function.

There is currently no universally accepted method to monitor circuit function or guidelines for circuit replacement during continuous renal replacement therapies (CRRT). The objectives of this study were to diagnose the causes of circuit failure, identify factors responsible for circuit clotting and determine a predictive monitor of circuit function. The CRRT technique used in this study was continuous venovenous haemodialysis (CVVHD). Continuous monitoring of circuit pressures (pre- and post-haemofilter and their difference: the transfilter pressure gradient) was used to diagnose the causes of circuit failure. In circuits ceasing due to clotting, the factors thought to contribute, anticoagulation, haematocrit and platelet count, were measured at the commencement of CVVHD and every eight hours thereafter until circuit failure. Monitors of circuit function, creatinine clearance and plasma to diafiltrate urea ratio were measured every eight hours and compared to the transfilter pressure gradient. During a three-month period data was collected on five consecutive patients (41 consecutive haemofilters). Clotting of the haemofilter (63%) and air detection chamber (7.5%) were the most common identifiable causes of circuit failure. The duration of their circuit life was described using multiple regression analysis, i.e. hours of filter life = -82.8 + (delta platelet count x 0.25) + (delta haematocrit x 3.6) + (circuit flow [ml/min] x 4) R2 = 0.77. A rise in transfilter pressure gradient and a fall in haemofilter function discriminated clotted filters with falling function (decrease in creatinine clearance and urea ratio) from unclotted filters. In any circuit an increase of 26 mmHg or more in the transfilter pressure gradient accurately predicted circuit failure due to clotting and imminent cessation of function. Increases in platelet count, haematocrit, and low circuit flows are important determinants of haemofilter life. The measurement of transfilter pressure gradient across the haemofilter is an accurate bedside monitor of circuit function.

Acute Kidney Injury↗
PubMed1995

Renovascular interaction of epinephrine, dopamine, and intraperitoneal sepsis.

OBJECTIVE: To determine the effect of intraperitoneal sepsis on the systemic and renal actions of the continous infusion of epinephrine or dopamine, and during the concurrent administration of both drugs. DESIGN: Prospective, randomized study. SETTING: Laboratory at a university hospital. SUBJECTS: Seven conscious, chronically catheterized, adult merino sheep. INTERVENTIONS: Epinephrine at 40 micrograms/min or dopamine at 2 micrograms/kg/min, or both drugs concurrently were infused for 4 hrs on separate study days in healthy sheep. This protocol was then repeated following the induction of sepsis after the intraperitoneal injection of 10(11) Escherichia coli, 10(12) Bacteroides fragilis, and bran. MEASUREMENTS AND MAIN RESULTS: Systemic oxygen delivery (DO2) and consumption were measured using thermodilution cardiac output and measured oxygen content. Renal blood flow was measured using an electromagnetic flow transducer, and creatinine clearance was calculated as the quotient of renal blood flow and the renal extraction ratio of creatinine. Infusion of epinephrine augmented systemic DO2 and mean arterial pressure (MAP) during both healthy and septic studies. Systemic oxygen consumption was only increased during epinephrine infusion in the septic study. During the healthy animal study, renal blood flow was initially decreased during epinephrine infusion, but increased to 36% above baseline (p = .003). However, creatinine clearance remained unchanged. During the experimental sepsis study, the infusion of epinephrine had less marked effects on renal blood flow (unchanged from baseline), while an initial reduction (15 mins) in creatinine clearance (p = .04) was not sustained and had returned to baseline by 3 hrs. Dopamine alone produced no change in systemic oxygen variables or MAP during the studies on healthy or septic animals. Although dopamine produced renal vasodilation and an increase in renal blood flow in the healthy state, these results were not found during the septic state. In addition, concurrent infusion of dopamine with epinephrine did not alter the systemic or renal effects of epinephrine during the healthy or septic states. CONCLUSIONS: These results do not support the routine use of low-dose dopamine, and demonstrate a change in renovascular responses to catecholamines during intraperitoneal sepsis. The infusion of epinephrine at 40 micrograms/min had few deleterious effects on the kidney, and augmented both MAP and systemic DO2. Its role as a catecholamine in the management of sepsis may need to be reconsidered.

Animals↗
PubMed1995

Serum surfactant protein-A levels in patients with acute cardiogenic pulmonary edema and adult respiratory distress syndrome.

Detection of alveolo-capillary damage has important implications for treatment modalities in ventilated patients. Although surfactant protein-A (SP-A) is normally only found in appreciable amounts in the lung, we describe significantly elevated concentrations in the sera of patients with acute cardiogenic pulmonary edema (median, 250 ng/ml; range, 180 to 364; n = 10) and in those with the adult respiratory distress syndrome (ARDS) (median, 378 ng/ml; range, 215 to 1,378; n = 15) relative to healthy control subjects (median, 175 ng/ml; range, 123 to 248; n = 15) and ventilated patients with no cardiorespiratory disease (median, 169 ng/ml; range, 126 to 253; n = 6) (p < 0.01, in all cases). Serum SP-A was inversely related to blood oxygenation and to static respiratory system compliance both at the time of the patient's entry into the study (p < 0.005, rs = -0.51, n = 31; p < 0.001, rs = 0.82, n = 17; respectively) and during the course of admission (p < 0.001, rs = -0.34, n = 168; p < 0.001, rs = -0.50, n = 111; respectively). In addition, we describe in detail three cases of ARDS where lung function either improved, remained static, or deteriorated. We conclude that serum SP-A is an acute indicator of lung function and alveolo-capillary membrane injury.

Adult↗
PubMed1995

Vasoactive drugs and the importance of renal perfusion pressure.

Despite the often multifactorial nature of renal insults in critically ill patients, inadequate renal blood flow (RBF) is common and frequently causes a reduction in the glomerular filtration rate (GFR). Renal autoregulation acts to maintain both the RBF and GFR constant across a broad range of renal perfusion pressure (RPP) levels; however, the lower limit of this range (approximately 80 mm Hg for RBF, and 10-15 mm Hg higher for GFR) is often above the RPP achieved in critically ill patients. Furthermore, renal autoregulation is often lost, resulting in a linear pressure-flow relationship in the "at-risk" kidney. Consequently, maintenance of an adequate RPP level is needed to optimize RBF. While this may require the use of vasopressor catecholamines with their attendant risk of renal vasoconstriction and a reduction in RBF, both laboratory studies and clinical data suggest that such reactions rarely occur with intravenous infusions of these drugs, and that RBF and renal function usually improve when RPP is augmented during shock. Preliminary data, using nitric oxide (NO.) synthase inhibitors to augment blood pressure, showed a detrimental effect on renal perfusion, perhaps due to the central role of NO. in the normal vasoregulation of the kidney. Dopaminergic agonists have been commonly used as renal vasodilators; however, their actions are complex and include a proximal tubular diuretic effect, renal vasodilation, and systemic hemodynamic effects. Their specific action to increase RBF and GFR has not been demonstrated in clinically relevant studies and no prospective randomized study has shown a reduction in the incidence of renal impairment or acute renal failure.

Acute Kidney Injury↗
PubMed1994

Determination of NG-nitro-L-arginine and NG-nitro-L-arginine methyl ester in plasma by high-performance liquid chromatography.

An HPLC method has been developed for the measurement of the nitric oxide synthase inhibitors, NG-nitro-L-arginine (L-NOLA) and NG-nitro-L-arginine methyl ester (L-NAME), in sheep plasma. Using an ion-exchange HPLC column (JWAS 150, 100 x 3.9 mm I.D., Millipore-Waters, Australia) and post-column ninhydrin detection, L-NOLA was separated from valine and other plasma amino acids. When added to sheep plasma, good recovery (mean 102%) and precision (mean coefficient of variation 2.7%) in the measurement of L-NOLA was obtained over the range 2-50 mg/l. L-NAME was unstable in sheep plasma at 37 degrees C, and was converted to L-NOLA with a half-life of 250 min. This method will permit pharmacokinetic parameters to be determined for these potential drugs, and will allow plasma drug concentrations to be correlated with the pharmacodynamic effects of these compounds.

Amino Acids↗
PubMed1994

Epinephrine infusion in sheep: systemic and renal hemodynamic effects.

OBJECTIVE: To evaluate the dose-response effects of graded epinephrine infusions on systemic and renal hemodynamics. DESIGN: Prospective, dose-response study. SETTING: Laboratory at a university hospital. SUBJECTS: Thirteen conscious, chronically catheterized, adult merino sheep. INTERVENTIONS: Ten sheep received five infusions of epinephrine (5, 10, 20, and 40 micrograms/min; the 40-micrograms/min dose was repeated) and a placebo (saline) on separate days (at least 1 day apart). Each drug infusion was administered for 4 hrs on separate days after a 90-min baseline was established. Plasma catecholamine values and renin activity were measured in an additional three sheep infused with 40 micrograms/min epinephrine. MEASUREMENTS AND MAIN RESULTS: Renal blood flow was measured, using an electromagnetic flow transducer; these data, along with aortic and pulmonary arterial pressure, were continuously recorded after analog-to-digital conversion. Cardiac output was intermittently measured by thermodilution. Epinephrine resulted in a dose-dependent increase in mean arterial pressure (p < .001), and in cardiac output at 30, 60, and 120 mins after the start of the infusion. Concurrently, systemic vascular resistance was initially depressed below baseline, but then gradually increased during the 4-hr infusion period. Although a dose-dependent increase in renal vascular resistance was found, 5- and 10-micrograms/min of epinephrine failed to alter renal vascular resistance. However, 20- and 40-micrograms/min of epinephrine increased renal vascular resistance by 77% and 94% respectively, at 10 mins, but these values decreased to 17% and 16% of baseline by 120 mins. Consequently, an early dose-dependent decrease in renal blood flow was also time dependent, with renal blood flow increasing back to or above baseline at all studied infusion rates of epinephrine. CONCLUSIONS: Using a clinically relevant dose regimen, epinephrine increased mean arterial pressure and cardiac output. Renal blood flow decreased transiently, but returned to baseline within 30 to 60 mins.

Analysis of Variance↗
PubMed1994

Intensive care costing methodology: cost benefit analysis of mask continuous positive airway pressure for severe cardiogenic pulmonary oedema.

Costing data for intensive care admissions is important, not only for unit funding, but also for cost outcome analysis of new therapies. This paper presents an intensive care episode costing methodology using the example of a cost-benefit analysis of mask CPAP for severe cardiogenic pulmonary oedema (CPO). This analysis examines the intervention of admitting all patients with severe CPO to the intensive care unit for mask CPAP, compared with the previous practice of admitting only patients failing conventional non-CPAP treatment and requiring mechanical ventilation. The episode costs were determined from a prospective study which showed mask CPAP reduced the need for mechanical ventilation from 35% to 0%. The mean cost of a mask CPAP episode was $1,156, with a mean stay of 1.2 days, compared with ventilated patients, $5,055 and 4.2 days. The major contributors to cost in both groups were nursing and medical salaries, and hospital overheads. The cost of previous estimated yearly caseload of 35 ventilated patients ($176,925) was greater than the cost associated with an increased caseload of 100 mask CPAP patients ($115,600). We conclude that, despite an increase in admissions, mask CPAP for severe CPO is cost-effective.

Cost-Benefit Analysis↗
PubMed1993

Efficacy of pressure support in compensating for apparatus work.

Breathing through an endotracheal tube, connector, and ventilator demand valve imposes an added load on the respiratory muscles. As respiratory muscle fatigue is thought to be a frequent cause of ventilator dependence, we sought to examine the efficacy of five different ventilators in reducing this imposed work through the application of pressure support ventilation. Using a model of spontaneous breathing, we examined the apparatus work imposed by the Servo 900-C, Puritan Bennett 7200a, Engstrom Erica, Drager EV-A or Hamilton Veolar ventilators, a size 7.0 and 8.0 mm endotracheal tube, and inspiratory flow rates of 40 and 60 l/min. Pressure support of 0, 5, 10, 15, 20 and 30 cm H2O was tested at each experimental condition. Apparatus work was greater with increased inspiratory flow rate and decreased endotracheal tube size, and was lowest for the Servo 900-C and Puritan Bennett 7200a ventilators. Apparatus work fell in a curvilinear fashion when pressure support was applied, with no major difference noted between the five ventilators tested. At an inspiratory flow rate of 40 l/min, a pressure support of 5 and 8 cm H2O compensated for apparatus work through size 8.0 and 7.0 endotracheal tubes and the Servo 900-C and Puritan Bennett 7200a ventilators. However, the maximum negative pressure was greater for the Servo 900-C. The added work of breathing through endotracheal tubes and ventilator demand valves may be compensated for by the application of pressure support. The level of pressure support required depends on inspiratory flow rate, endotracheal tube size, and type of ventilator.

Equipment Design↗
PubMed1992

Prospective evaluation of residents and nurses as severity score data collectors.

OBJECTIVES: To determine the interobserver reliability of residents and nurses collecting Acute Physiology and Chronic Health Evaluation (APACHE II) data and the subsequent effect of these data collections on individual patient mortality prediction. DESIGN: In a prospective study, residents and nurses independently collected data to derive APACHE II scores. When their scores differed, a standard score was determined by one of the investigators. SETTING: A general medical and surgical ICU. PATIENTS: A total of 120 consecutive patients were included; of these patients, 79 had standard scores determined because resident and nurse scores differed. MAIN RESULTS: There was overall agreement between the residents and nurses with no significant difference between mean APACHE II scores or mean predicted mortality rates. Intraclass correlation coefficients confirmed good overall agreement between observer groups for predicted mortality rate: resident vs. nurse r2 = .94, resident vs. standard r2 = .94, and nurse vs. standard r2 = .90. However, clinically significant lack of agreement was demonstrated in 5% of the patients by the 95% confidence limits of agreement: resident vs. nurse -14 to +14%, resident vs. standard -10 to +14%, and nurse vs. standard -14 to +20%. CONCLUSIONS: While interobserver variability between resident and nurse data collection has minimal effect on derived predicted mortality rate with large patient groups, significant variability may occur in individual patients. Residents were more accurate data collectors than nurses.

Data Collection↗