Pulmonary capillary pressures during the acute respiratory distress syndrome

Objectives: (1)To describe the evolution of pulmonary capillary pressure (Pcap) and of the pressure drop across the pulmonary venous bed from early to established acute respiratory distress syndrome (ARDS), (2) to assess Pcap under different levels of positive end-expiratory pressure (PEEP) and (3) to compare the visual method and a mathematical model to determine Pcap. Design: Prospective, intervention study. Setting: Intensive care unit in a teaching institution. Patients: Nine ARDS patients, according to the ARDS Consensus Conference criteria. Interventions: Pulmonary arterial pressures were measured during routine respiratory mechanics measurements throughout ARDS. Four PEEP levels (6, 9, 12 and 15cmH2O) were studied. Measurements and results: Pulmonary artery occlusions were made in triplicate at each PEEP level. Pcap was determined for every occlusion trace by three observers (visual method) and a mathematical model. Diastolic pulmonary artery pressure (PAPd) and pulmonary artery occlusion pressure (PAOP) were measured. The visually determined Pcap showed a bias of 2.5±2.1mmHg as compared to the mathematical estimation. PAPd, Pcap and PAOP tended to decrease from early to late ARDS (p=0.128, 0.265, 0.121). Pcap−PAOP (6.3±2.7mmHg) did not change throughout ARDS. Higher PEEP levels were associated with increased PAPd, Pcap and PAOP, as well as with larger Pcap−PAOP throughout ARDS. Conclusions: Pulmonary capillary pressure cannot be predicted from PAOP during early and established ARDS. The high variability in Pcap−PAOP increases the risk for underestimation of filtration pressures and consequently the risk for lung edema. Pcap can be estimated at the bedside by either the visual or mathematical method

Need for critical care in gynaecology: a population-based analysis

INTRODUCTION: The purpose of this study was to note potential gynaecological risk factors leading to intensive care and to estimate the frequency, costs and outcome of management. MATERIALS AND METHODS: In a cross-sectional study of intensive care admissions in Kuopio from March 1993 to December 2000, 23 consecutive gynaecological patients admitted to a mixed medical-surgical intensive care unit (ICU) were followed. We recorded demographics, admitting diagnoses, scores on the Acute Physiological and Chronic Health Evaluation (APACHE) II, clinical outcome and treatment costs. RESULTS: The overall need for intensive care was 2.3 per 1000 women undergoing major surgery during the study period. Patients were 55.4 ± 16.9 (mean ± SD) years old, with a mean APACHE II score of 14.07 (± 5.57). The most common diagnoses at admission were postoperative haemorrhage (43%), infection (39%) and cardiovascular disease (30%). The duration of stay in the ICU was 4.97 (± 9.28) (range 1–42) days and the mortality within 6 months was 26%, although the mortality in the ICU was 0%. The total cost of intensive care was approximately US$7044 per patient. CONCLUSIONS: Very few gynaecological patients develop complications requiring intensive care. The presence of gynaecological malignancy and pre-existing medical disorders are clinically useful predictors of eventual outcome, but many cases occur in women with a low risk and this implies that the risk is relevant to all procedures. Further research is needed to determine effective preventive approaches

The effect of interruption to propofol sedation on auditory event-related potentials and electroencephalogram in intensive care patients

INTRODUCTION: In this observational pilot study we evaluated the electroencephalogram (EEG) and auditory event-related potentials (ERPs) before and after discontinuation of propofol sedation in neurologically intact intensive care patients. METHODS: Nineteen intensive care unit patients received a propofol infusion in accordance with a sedation protocol. The EEG signal and the ERPs were measured at the frontal region (Fz) and central region (Cz), both during propofol sedation and after cessation of infusion when the sedative effects had subsided. The EEG signal was subjected to power spectral estimation, and the total root mean squared power and spectral edge frequency 95% were computed. For ERPs, we used an oddball paradigm to obtain the N100 and the mismatch negativity components. RESULTS: Despite considerable individual variability, the root mean squared power at Cz and Fz (P = 0.004 and P = 0.005, respectively) and the amplitude of the N100 component in response to the standard stimulus at Fz (P = 0.022) increased significantly after interruption to sedation. The amplitude of the N100 component (at Cz and Fz) was the only parameter that differed between sedation levels during propofol sedation (deep versus moderate versus light sedation: P = 0.016 and P = 0.008 for Cz and Fz, respectively). None of the computed parameters correlated with duration of propofol infusion. CONCLUSION: Our findings suggest that use of ERPs, especially the N100 potential, may help to differentiate between levels of sedation. Thus, they may represent a useful complement to clinical sedation scales in the monitoring of sedation status over time in a heterogeneous group of neurologically intact intensive care patients

Early non-invasive cardiac output monitoring in hemodynamically unstable intensive care patients: A multi-center randomized controlled trial

Introduction Acute hemodynamic instability increases morbidity and mortality. We investigated whether early non-invasive cardiac output monitoring enhances hemodynamic stabilization and improves outcome. Methods A multicenter, randomized controlled trial was conducted in three European university hospital intensive care units in 2006 and 2007. A total of 388 hemodynamically unstable patients identified during their first six hours in the intensive care unit (ICU) were randomized to receive either non-invasive cardiac output monitoring for 24 hrs (minimally invasive cardiac output/MICO group; n = 201) or usual care (control group; n = 187). The main outcome measure was the proportion of patients achieving hemodynamic stability within six hours of starting the study. Results The number of hemodynamic instability criteria at baseline (MICO group mean 2.0 (SD 1.0), control group 1.8 (1.0); P = .06) and severity of illness (SAPS II score; MICO group 48 (18), control group 48 (15); P = .86)) were similar. At 6 hrs, 45 patients (22%) in the MICO group and 52 patients (28%) in the control group were hemodynamically stable (mean difference 5%; 95% confidence interval of the difference -3 to 14%; P = .24). Hemodynamic support with fluids and vasoactive drugs, and pulmonary artery catheter use (MICO group: 19%, control group: 26%; P = .11) were similar in the two groups. The median length of ICU stay was 2.0 (interquartile range 1.2 to 4.6) days in the MICO group and 2.5 (1.1 to 5.0) days in the control group (P = .38). The hospital mortality was 26% in the MICO group and 21% in the control group (P = .34). Conclusions Minimally-invasive cardiac output monitoring added to usual care does not facilitate early hemodynamic stabilization in the ICU, nor does it alter the hemodynamic support or outcome. Our results emphasize the need to evaluate technologies used to measure stroke volume and cardiac output--especially their impact on the process of care--before any large-scale outcome studies are attempted

Effect of levosimendan in experimental verapamil- induced myocardial depression

Background: Calcium antagonist overdose can cause severe deterioration of hemodynamics unresponsible to treatment with beta adrenergic inotropes. The aim of the study was to evaluate in an experimental model the effects of levosimendan during severe calcium antagonist intoxication. Methods: Twelve landrace-pigs were intoxicated with intravenous verapamil at escalating infusion rates. The infusion containing 2.5 mg/ml verapamil was used aiming to a reduction of cardiac output by 40 % from the baseline value. Intoxicated pigs were randomized into two groups: control (saline) and levosimendan (intravenous bolus). Inotropic effect was measured as a change in a maximum of the positive slope of the left ventricular pressure (LV dP/dt). The survival and hemodynamics of the animals were followed for 120 min after the targeted reduction of cardiac output. Results: In the control group, five out of six pigs died during the experiment. In the levosimendan group, one pig died before completion of the experiment (p = 0.04). In the levosimendan group a change in LV dP/dt was positive in four out of six pigs compared to one out of six pigs in the control group (p = ns). Conclusions: In this experimental model, the use of levosimendan was associated with improved survival. Background In the year 2004 more than 10000 toxic exposures to calciu