Background. Dynamic arterial elastance (Ea dyn ), the relationship between pulse pressure variation (PPV) and stroke volume variation (SVV), has been suggested as a functional assessment of arterial load. The aim of this study was to evaluate the impact of arterial load changes during acute pharmacological changes, fluid administration, and haemorrhage on Ea dyn . Methods. Eighteen anaesthetized, mechanically ventilated New Zealand rabbits were studied. Arterial load changes were induced by phenylephrine ( n =9) or nitroprusside ( n =9). Thereafter, animals received a fluid bolus (10 ml kg -1 ), followed by stepwise bleeding (blood loss: 15 ml kg -1 ). The influence of arterial load and cardiac variables on PPV, SVV, and Ea dyn was analysed using a linear mixed-effects model analysis. Results. After phenylephrine infusion, mean ( sd ) Ea dyn decreased from 0.89 (0.14) to 0.49 (0.12), P <0.001; whereas after administration of nitroprusside, Ea dyn increased from 0.80 (0.23) to 1.28 (0.21), P <0.0001. Overall, the fluid bolus decreased Ea dyn [from 0.89 (0.44) to 0.73 (0.35); P <0.01], and haemorrhage increased it [from 0.78 (0.23) to 0.95 (0.26), P =0.03]. Both PPV and SVV were associated with similar arterial factors (effective arterial elastance, arterial compliance, and resistance) and heart rate. Furthermore, PPV was also related to the acceleration and peak velocity of aortic blood flow. Both arterial and cardiac factors contributed to the evolution of Ea dyn throughout the experiment. Conclusions. Acute modifications of arterial load induced significant changes on Ea dyn ; vasodilatation increased Ea dyn , whereas vasoconstriction decreased it. The Ea dyn was associated with both arterial load and cardiac factors, suggesting that Ea dyn should be more properly considered as a ventriculo-arterial coupling index.

P001 - Sepsis impairs the capillary response within hypoxic capillaries and decreases erythrocyte oxygen-dependent ATP efflux

An effective fluid challenge should increase the mean systemic filling pressure (Pmsf ) in order to increase the venous return. The objective of this study was to determine the minimum volume of intravenous fluid required to significantly increase the Pmsf.

Dynamic arterial elastance (Eadyn), the relationship between pulse pressure variation (PPV) and stroke volume variation (SVV), has been suggested as a functional assessment of arterial load for predicting the arterial pressure response after volume expansion (VE)1. Although changes in Eadyn have been related with variations in arterial load2, the effect of acute arterial tone changes on Eadyn and the impact on its performance for predicting the arterial pressure response after VE has not yet been determined.

Intensive Care Units (ICUs) can be immensely noisy places, where high noise levels may have deleterious effects on patients, visitors and staff alike. Many studies have identified sound levels exceeding World Health Organisation's recommendations, although very few measured for more than 24 h or concurrently in multiple locations, as normally done in outdoor studies. In order to assess the feasibility of installing a continuous monitoring system in the indoor environment of an 18 bedded general intensive care, a MEMS-based microphone was used to monitor the noise levels for 7 days. Results showed minimal variation between night and day, but changes in sound level could be correlated with regularly occurring activities. The impact of microphone-holding structure on the measurements and the possibility of inferring patient and visitor' exposure from a fixed measurement position are also discussed. Laboratory analysis, confirmed by in situ testing, identified ideal microphone positioning, and led to a correction of -1 dB for the sound pressure level measured at the microphone to obtain the level experienced by the patient. Crown Copyright (C) 2013 Published by Elsevier Ltd. All rights reserved.

BACKGROUND: Dynamic arterial elastance (Eadyn), defined as the pulse pressure variation (PPV) to stroke volume variation (SVV) ratio, has been suggested as a predictor of the arterial pressure response to fluid administration. In this study, we assessed the effectiveness of Eadyn to predict the arterial blood pressure response to a fluid challenge (FC) in preload-dependent, spontaneously breathing patients. METHODS: Patients admitted postoperatively and monitored with the Nexfin monitor (BMEYE, Amsterdam, The Netherlands) were enrolled in the study. Patients were included in the analysis if they were spontaneously breathing and had an increase in cardiac output ≥10% during an FC. Patients were classified according to the increase in mean arterial blood pressure (MAP) after FC into MAP-responders (MAP increase ≥10%) and MAP-nonresponders (MAP increase <10%). Eadyn was continuously calculated from the PPV and SVV values obtained from the monitor. RESULTS: Thirty-four FCs from 26 patients were studied. Seventeen FCs (50%) induced a positive MAP response. Preinfusion Eadyn was significantly higher in MAP-responders (1.39 ± 0.41 vs 0.85 ± 0.23; P = 0.0001). Preinfusion Eadyn predicted a positive MAP response to FC with an area under the receiver-operating characteristic curve of 0.92 ± 0.04 of standard error (95% confidence interval, 0.78-0.99; P < 0.0001). A preinfusion Eadyn value ≥1.06 (gray zone: 0.9-1.15) discriminated MAP-responders with a sensitivity and specificity of 88.2% (approximate 95% confidence interval, 64%-99%), respectively. CONCLUSIONS: Noninvasive Eadyn, defined as the PPV to SVV ratio, predicted the arterial blood pressure increase to fluid administration in spontaneously breathing, preload-dependent patients.

Patients with limited cardiopulmonary reserve are at risk of mortality and morbidity after major surgery. Augmentation of oxygen delivery index (DO2I) with i.v. fluids and inotropes (goal-directed therapy, GDT) has been shown to reduce postoperative mortality and morbidity in high-risk patients. Concerns regarding cardiac complications associated with fluid challenges and inotropes may prevent clinicians from performing GDT in patients who need it most. We hypothesized that GDT is not associated with an increased risk of cardiac complications in high-risk, non-cardiac surgical patients. We performed a systematic search of Medline, Embase, and CENTRAL databases for randomized controlled trials (RCTs) of GDT in high-risk surgical patients. Studies including cardiac surgery, trauma, and paediatric surgery were excluded. We reviewed the rates of all cardiac complications, arrhythmias, myocardial ischaemia, and acute pulmonary oedema. Meta-analyses were performed using RevMan software. Data are presented as odds ratios (ORs), [95% confidence intervals (CIs)], and P-values. Twenty-two RCTs including 2129 patients reported cardiac complications. GDT was associated with a reduction in total cardiovascular (CVS) complications [OR=0.54, (0.38-0.76), P=0.0005] and arrhythmias [OR=0.54, (0.35-0.85), P=0.007]. GDT was not associated with an increase in acute pulmonary oedema [OR=0.69, (0.43-1.10), P=0.12] or myocardial ischaemia [OR=0.70, (0.38-1.28), P=0.25]. Subgroup analysis revealed the benefit is most pronounced in patients receiving fluid and inotrope therapy to achieve a supranormal DO2I, with the use of minimally invasive cardiac output monitors. Treatment of high-risk surgical patients GDT is not associated with an increased risk of cardiac complications; GDT with fluids and inotropes to optimize DO2I during early GDT reduces postoperative CVS complications.

Al-Subaie, N.; Reynolds, T.; Myers, A.; Sunderland, R.; Rhodes, A.; Grounds, R.M.; Hall, G.M.Author Information

BACKGROUND:In this study we quantify the ability of dynamic cardiovascular parameters measured by the PulseCO™ algorithm of the LiDCO™plus monitor to predict the response to a fluid challenge in post-operative patients. METHODS:Surgical patients, admitted to the Intensive Care Unit from the operating theatre were monitored with the LiDCO™plus system. A number of static and dynamic cardiovascular measurements were recorded before and after a fluid challenge. Receiver Operator Characteristic (ROC) curve analysis was used to identify the baseline values, with optimum sensitivity and specificity, to predict responsiveness to a fluid challenge. RESULTS:Thirty-one patients were enrolled, and received protocol-based fluid challenges. Twelve (38%) responded by demonstrating an increase in stroke volume of >15%. Heart rate (HR) and central venous pressure (CVP) were not statistically different between responders and non-responders. Mean arterial pressure (mAP), systolic pressure variation (SPV), pulse pressure variation (PPV) and stroke volume variation (SVV) were statistically different between responders and non-responders. Parameters with a ROC area under the curve (AUC) significantly >0.5 included SPV 0.70 (0.52-0.88) P=0.046, PPV 0.87 (0.76-0.99) P<0.0002 and SVV 0.84 (0.71-0.96) P=0.0005. The best cut-off values (sensitivity and specificity) to predict fluid were SPV >9 mmHg (73%, 76%), PPV >13% (83%, 74%) and SVV >12.5% (75%, 83%). ROC analysis did not show the AUC to be significantly >0.5 for HR, mAP and CVP CONCLUSION: Dynamic indices measured by PulseCO™ (LiDCO) have a high sensitivity and specificity in predicting fluid responsiveness in sedated and mechanically ventilated patients. A cut-off value for PPV of 13% is the most sensitive and specific indicator of fluid responsiveness.

BACKGROUND Recent work suggests that increased plasma concentrations of cardiac troponin I (cTnI) are common in critically ill patients and are associated with poor outcome. We measured the frequency of increased plasma cTnI concentrations during patients' stay in a mixed medical/surgical intensive care unit (ICU) and compared our findings with hospital mortality. METHODS Basic details, organ support, and hospital mortality were recorded for all patients treated in ICU during a 6 month period. cTnI concentrations were sampled daily for all patients, using 0.04 µg litre(-1) as the upper limit of normal, and 0.12 µg litre(-1) as an additional stratification point. RESULTS Of 663 patients, 54% were male, with a mean (sd) age of 60 (18) yr, 65% were surgical patients, and the median Acute Physiology and Chronic Ill Health II (APACHE II) score was 15 (inter-quartile range 12-20). Increased cTnI concentrations were found in 345 patients (52%) while in ICU. One hundred and twenty patients (18%) died in hospital. cTnI concentration >0.04 µg litre(-1) was associated with reduced odds of hospital survival, independent of age, medical admission, unplanned admission, APACHE II score, mechanical ventilation, and haemofiltration (adjusted odds ratio 0.25, 95% confidence interval 0.08-0.75, P=0.014). Stratification by the degree of cTnI increase revealed an incremental trend towards a lower odds of hospital survival, including for patients with 'minor' elevations of cTnI (0.05-0.12 µg litre(-1)). CONCLUSIONS Increased serum cTnI concentrations during ICU stay independently predicts hospital mortality, even when the threshold is low. We found a trend towards an association between 'minor' elevations in cTnI and higher in-hospital mortality.

BACKGROUND Pulse pressure (PP) analysis from a radial arterial line is available with the LiDCO plus monitor (LiDCO, Cambridge, UK) and FloTrac/Vigileo (Edwards Lifesciences, Irvine, CA, USA). The aim of this study was to investigate the agreement of continuous PP analysis against intermittent thermodilution (ITD) using the pulmonary artery catheter (PAC). METHODS This was a six-hour study in 29 patients monitored with a PAC. All measurements were referenced against CO measured from the average of four ITD curves from the PAC. The LiDCO plus was calibrated with a lithium dilution (PulseCOLi) and with ITD (PulseCOITD) at baseline. Measurements from Vigileo software 1.03 (APCO), LiDCO plus (PulseCOLi and PulseCOITD), CCO and ITD were taken every hour for the next six hours. The bias and precision between the two devices were calculated as well as the percentage error (PE) of agreement between the tested device and the reference. The coefficient of variation (CV) of the tested device was then derived. RESULTS The average bias, PE and coefficient of variation for CCO vs. ITD of the tested device were 0.3 L/min, 28% and 13%, respectively; for APCO vs. ITD the calculations were -1.1 L/min, 55% and 27%; for PulseCOLi Cardiac output Blood pressure Thermodilution. ITD they were 0.5 L/min, 40% and 19%; and for PulseCOITD vs. ITD they were 0.2 L/min, -31% and 15%. CONCLUSION APCO (Vigileo software 1.03) and PulseCOLi showed a moderate agreement with the PAC. When PulseCO was calibrated with ITD (PulseCOITD) it showed excellent agreement, demonstrating that PulseCO performs well against ITD when the calibration process is optimally performed.

Medical mistakes have been identified as resulting from a breakdown in one or more of five major areas: equipment performance, communication, staffing levels, complex environments and workloads. Because many of these areas relate directly to the practice of anesthesiology, they can contribute significantly to the safety and quality of the use of anesthesia. The specialty of anesthesia has embraced a culture of safety, resulting in many beneficial improvements for patients. The avoidance of error has led to improved outcomes, with a decrease in directly attributable rates of morbidity and mortality. Despite these improved rates, there are still areas that can be improved. This paper describes the background of these issues, discusses areas where performance has improved and identifies the areas in which there is room for further improvement.

BACKGROUND Recent studies have found plasma C-reactive protein (CRP) to be a predictor of outcome after discharge from the intensive care unit (ICU). To assess the generalizability of this finding, we assessed the value of CRP on the day of ICU discharge as a predictor of unplanned ICU readmission and unexpected death within 2 weeks. Plasma albumin and white cell count at discharge were also considered as markers associated with ongoing inflammation. METHODS This was a single-centre observational study involving a medical-surgical ICU in a university teaching hospital. Data were prospectively collected from 1487 admissions involving 1401 patients over a 12 month period. Patients' admission details and APACHE II score were collected in addition to plasma CRP, white cell count, and albumin values from the day of discharge from ICU. We assessed the difference in these variables between patients who were readmitted, who died unexpectedly, and those who did not. RESULTS We found that 9.9% of patients discharged were either readmitted (7.0%) or died unexpectedly (2.9%). Patients who were readmitted had a lower plasma albumin concentration [20 (16, 24) vs 22 (19, 27), P<0.001] and a higher admission APACHE II score [median (inter-quartile range, IQR) 16.5 (13, 21) vs 15 (12, 18), P=0.02]. Patients who died unexpectedly on the ward were older [mean (sd): 76 (12) vs 59 (19), P<0.001] and had a higher APACHE II score [21 (17.25, 26) vs 15 (12, 18), P<0.001]. There was not a statistically significant difference in CRP concentration between patients who either required ICU readmissions or died unexpectedly on the ward and those who did not. CONCLUSIONS In a mixed medical-surgical intensive care, plasma CRP measured at the day of discharge from intensive care is not a predictor of readmissions or deaths.

BACKGROUND:Hospital admissions for cirrhosis have been increasing in the United Kingdom, leading to increased pressure on intensive care (ICU) services. Outcome data for patients admitted to ICU are currently limited to transplant centre reports, with mortality rates exceeding 70%. These tertiary reports could fuel a negative bias when patients with cirrhosis are reviewed for ICU admission in secondary care.AIMS:To determine whether disease severity and mortality rates in non-transplant general ICU are less severe than those reported by tertiary datasets.METHODS:A prospective dual-centre non-transplant ICU study. Admissions were screened for cirrhosis and physiological and biochemical data were collected. Disease-specific and critical illness scoring systems were evaluated.RESULTS:Cirrhosis was present in 137/4198 (3.3%) of ICU admissions. ICU and hospital mortality were 38% and 47%, respectively; median age 50 [43-59] years, 68% men, 72% alcoholic cirrhosis, median Child Pugh Score (CPS) 10 [8-11], Model for End-Stage Liver Disease (MELD) 18 [12-24], Acute Physiology and Chronic Health Evaluation II score (APACHE II) 16 [13-22].CONCLUSIONS:Mortality rates and disease staging were notably lower than in the published literature, suggesting that patients have a more favourable outlook than previously considered. Transplant centre data should therefore be interpreted with caution when evaluating the merits of intensive care admission for patients in general secondary care ICUs.