Variability in outcome and resource use in intensive care units

Objective To examine variability in outcome and resource use between ICUs. Secondary aims: to assess whether outcome and resource use are related to ICU structure and process, to explore factors associated with efficient resource use. Design and setting Cohort study, based on the SAPS 3 database in 275 ICUs worldwide. Patients 16,560 adults. Measurements and results Outcome was defined by standardized mortality rate (SMR). Standardized resource use (SRU) was calculated based on length of stay in the ICU, adjusted for severity of acute illness. Each unit was assigned to one of four groups: “most efficient” (SMR and SRU < median); “least efficient” (SMR, SRU > median); “overachieving” (low SMR, high SRU), “underachieving” (high SMR, low SRU). Univariate analysis and stepwise logistic regression were used to test for factors separating “most” from “least efficient” units. Overall median SMR was 1.00 (IQR 0.77–1.28) and SRU 1.07 (0.76–1.58). There were 91 “most efficient”, 91 “least efficient”, 47 “overachieving”, and 46 “underachieving” ICUs. Number of physicians, of full-time specialists, and of nurses per bed, clinical rounds, availability of physicians, presence of emergency department, and geographical region were significant in univariate analysis. In multivariate analysis only interprofessional rounds, emergency department, and geographical region entered the model as significant. Conclusions Despite considerable variability in outcome and resource use only few factors of ICU structure and process were associated with efficient use of ICU. This suggests that other confounding factors play an important role. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. This research was supported financially by the European Society of Intensive Care Medicine (ESICM), Portuguese Society of Intensive Care (SPCI), Austrian Centre for Documentation and Quality Assurance in Intensive Care Medicine (ASDI), iMDsoft Corp., and Fund of the Austrian National Bank (project 10995 ONB). This article is discussed in the editorial available at: .     

Continuous measurement of cardiac output by the Fick principle: clinical validation in intensive care.

OBJECTIVE: To compare continuous measurement of cardiac output by the Fick principle with the thermodilution cardiac output technique in hemodynamically unstable patients. DESIGN: An open comparison of two methods. SETTING: Multidisciplinary ICU in a university hospital. PATIENTS: Eight patients after coronary bypass surgery and 13 patients with hyperdynamic septic shock. All patients were mechanically ventilated. MEASUREMENTS AND MAIN RESULTS: The continuous Fick cardiac output technique was compared with the thermodilution cardiac output using both warm and cold injection in the coronary artery bypass surgery patients and using warm injection only in the patients with hyperdynamic septic shock. The mean difference between the continuous cardiac output technique and all thermodilution measurements (n = 201) was 0.6 +/- 19%. There was a good correlation between the continuous cardiac output and the warm thermodilution technique (n = 125, r2 = .79; p less than .001). When consecutive measurements with warm and cold thermodilution were compared with the respective Fick-derived values (n = 76), the mean differences between the Fick-derived and the warm and cold thermodilution cardiac output values were 0.2 +/- 1.0 L/min and 0.3 +/- 1.0 L/min, respectively. The relationship between Fick-derived and both methods of thermodilution-derived cardiac output was relatively constant during different modes of ventilatory support. The correlation between the thermodilution measurements with cold and room temperature injectate was weak (r2 = .36; p less than .001), whereas a good correlation was observed between the respective Fick-derived values (r2 = .73; p less than .001). The mean difference between the warm and cold thermodilution cardiac output measurements was 0.1 +/- 1.1 L/min and between the corresponding Fick-derived measurements was 0.01 +/- 0.7 L/min. CONCLUSIONS: Continuous measurement of cardiac output by the Fick principle offers a convenient, reproducible method for hemodynamic monitoring of unstable patients. The variation between the two tested thermodilution techniques is likely to reflect relatively rapid dynamic variation of cardiac output, which is filtered in the 1-min average of cardiac output obtained by the continuous Fick technique.     

Screening, treatment and adherence to treatment for hypertension

The population aged 40 to 64 years of the municipality of K?yli?, situated in southwestern Finland, was screened for hypertension in 1973-74; a total of 1018 persons (92%) participated in the program. On the basis of two separate blood pressure measurements a total of 147 hypertensive individuals who were not under treatment were identified. These individuals were divided into two groups by randomization of matched pairs. One group (the control group) was merely advised by letter to see a physician for raised blood pressure, while the other group (the experimental group), in addition to being so notified, received written information explaining the nature of hypertension and the importance of its treatment. After two years, the individuals in both groups were invited for a follow-up blood-pressure measurement, with the object of investigating the number of individuals who had sought treatment and who had continued it, and the differences between the groups in treatment seeking and adherence. A total of 79% of those who were notified to seek medical care had done so. Antihypertensive drug therapy had been begun for 85% of these. After two years, 56% of those who had been found initially to be hypertensive and who were seen in the follow-up were still under treatment. In 43% of these the blood pressure was at the target level. No statistically significant differences in treatment seeking and adherence to it were found between the experimental and control groups, nor were differences found in the decline in the blood pressure or its target levels. Comparing with other studies shows, that results can be better if the health care system that carries out the screening procedure for hypertension also take active steps to bring the patient under treatment and keep him on the regimen.     

Gastric-arterial PCO2 gradient does not reflect systemic and splanchnic hemodynamics or oxygen transport after cardiac surgery

Gastric mucosal-arterial PCO2 gradient (P(g-a)CO2) is used to assess splanchnic perfusion and oxygenation. We evaluated whether P(g-a)CO2 reflects whole body (Q) and splanchnic (Qsp) blood flow, oxygen delivery (DO2) and consumption (VO2) after coronary artery by pass graft (CABG) operation. Thirty patients received dobutamine or dopexamine to increase cardiac index, 15 patients enalapril or sodium nitroprusside to lower blood pressure, and 30 patients were controls. We measured Q, Qsp (hepatic vein catheter and indocyanine green), and gastric mucosal PCO2 (nasogastric tonometer) before and after interventions. Multiple linear regression model showed that none of the changes in Q, Qsp, and splanchnic or systemic DO2 and VO2 significantly explained changes in P(g-a)CO2 (deltaP(g-a)CO2). All independent variables together explained only 7% of deltaP(g-a)CO2. Increased splanchnic blood flow (0.65 +/- .19 vs. 0.94 +/- .31 L/min/m2, P < 0.001) and increased splanchnic DO2 (101 +/- 28 vs. 143 +/- 42 mL/min/m2, P < 0.001) during catecholamine infusions were associated with increased P(g-a)CO2 (8 +/- 8 vs. 11 +/- 7 mmHg, P = 0.003). P(g-a)CO2 does not reflect whole body or splanchnic blood flow, DO2 or VO2 after CABG operations. The physiology of P(g-a)CO2 is complex and therefore it is difficult for clinicians to interpret changes in gastric mucosal-arterial PCO2 gradient in individual patients after cardiac surgery.     

Peripheral and liver tissue oxygen tensions in hemorrhagic shock.

BACKGROUND AND METHODS: Hepatic dysfunction after severe hemorrhagic shock is common and may be a consequence of visceral tissue hypoxia. Peripheral tissue PO2 has been suggested to correlate with the development of visceral hypoxia. To test the hypothesis that changes in peripheral tissue PO2 reflect changes in hepatic PO2, we measured subcutaneous PO2, transcutaneous PO2, transconjunctival PO2, and liver tissue PO2, and their relationship with changes in mean arterial blood pressure (MAP) and systemic oxygen transport (DO2), during progressive bleeding in pigs (n = 23). In addition to the tissue PO2, portal vein PO2 and circulating lactate concentrations were also measured in six of the animals. The animals were anesthetized and bled to an MAP of 50 mm Hg within 1 hr. RESULTS: After an induced 10% reduction of MAP, only the DO2 decreased significantly (p less than .05). After a 20% reduction of MAP, the DO2 decreased further and was associated with a significant (p less than .05) reduction of all peripheral tissue PO2 values. A significant (p less than .05) reduction of liver tissue PO2 was observed later during bleeding, after induction of a 30% reduction in MAP. In the subgroup with portal venous PO2 and lactate measurements, reductions of all peripheral tissue PO2 and portal venous PO2 values occurred after a 20% reduction (p less than .05) of MAP. An increase (p less than .05) in the portal venous lactate concentration was observed after a 50% reduction of MAP, and a decrease (p less than .05) in liver tissue PO2 was noted after a 60% reduction of MAP. CONCLUSIONS: Reductions of both peripheral and portal venous PO2 values occur early during hemorrhage. The liver tissue PO2, though initially low, appears to be better defended, suggesting either redistribution of splanchnic blood flow or adaptation in hepatic oxygen demand.     

The effect of dobutamine infusion on splanchnic blood flow and oxygen transport in patients with acute pancreatitis

Objectives: To measure the blood flow distribution and oxygen transport in pancreatitis and to evaluate the regional effects of increased systemic blood flow. Design: Nonrandomized controlled trial. Setting: A general intensive care unit in a tertiary care center. Patients: 10 patients with pancreatitis requiring mechanical ventilation were studied after fluid resuscitation, and for the response to dobutamine, the patients served as their own controls. For the baseline, 11 patients scheduled for elective abdominal surgery served as a control group. Interventions: Systemic and regional hemodynamics were measured after fluid resuscitation to predefined hemodynamic endpoints. In patients with pancreatitis, the measurement was repeated after cardiac output had been increased by at least 25 % by dobutamine. Measurements and results: Hepatosplanchnic blood flow was estimated using regional catheterization and the dye dilution method. In patients with pancreatitis, the cardiac index did not differ from that of the control group (3.9 ± 0.8 vs 4.1 ± 0.7 l · min^–1· m^–2;NS). Accordingly, there was no difference in the splanchnic blood flow (1.1 ± 0.4 vs 1.2 ± 0.5 l · min^–1· m^–2;NS). Systemic and splanchnic oxygen consumption was increased in patients with pancreatitis (179 ± 25 vs 147 ± 27 ml · min^–1· m^–2, p < 0.05 and 68 ± 15 vs 49 ± 19 ml · min^–1· m^–2, p < 0.05), and systemic and splanchnic oxygen extraction was higher (0.34 ± 0.08 vs23 ± 0.05, p < 0.01 and 0.46 ± 0.18 vs 0.28 ± 0.08, p < 0.05, respectively). Dobutamine had inconsistent effects on splanchnic blood flow: in individual patients, splanchnic blood flow even decreased substantially. Conclusions: In severe pancreatitis, oxygen consumption is increased in the splanchnic region; increased splanchnic oxygen demand is not always met by adequately increased blood flow. Increasing the systemic blood flow with dobutamine does not improve perfusion in the splanchnic bed. Received: 24 September 1996 Accepted: 5 May 1997     

Ultrasound transmission measurements for tensile strength evaluation of tablets

Ultrasound transmission measurements were performed to evaluate the tensile strength of tablets. Tablets consisting of one ingredient were compressed from dibasic calcium phosphate dehydrate, two grades of microcrystalline cellulose and two grades of lactose monohydrate powders. From each powder, tablets with five different tensile strengths were directly compressed. Ultrasound transmission measurements were conducted on every tablet at frequencies of 2.25 MHz, 5 MHz and 10 MHz and the speed of sound was calculated from the acquired waveforms. The tensile strength of the tablets was determined using a diametrical mechanical testing machine and compared to the calculated speed of sound values. It was found that the speed of sound increased with the tensile strength for the tested excipients. There was a good correlation between the speed of sound and tensile strength. Moreover, based on the statistical tests, the groups with different tensile strengths can be differentiated from each other by measuring the speed of sound. Thus, the ultrasound transmission measurement technique is a potentially useful method for non-destructive and fast evaluation of the tensile strength of tablets.