Cytomegalovirus Serostatus as Predictor for Adverse Events After Cardiac Surgery: A Prospective Observational Study.

OBJECTIVE: To clarify whether reactivated cytomegalovirus (CMV) infections in critically ill patients lead to worse outcome or just identify more severely ill patients. If CMV has a pathogenic role, latently infected (CMV-seropositive) patients should have worse outcome than seronegative patients because only seropositive patients can experience a CMV reactivation. DESIGN: Post-hoc analysis of a prospective observational study. SETTING: Single university hospital. PARTICIPANTS: The study comprised 983 consecutive patients scheduled for on-pump surgery. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: CMV antibodies were analyzed in preoperative plasma samples. Postoperative adverse events (reintubation, low cardiac output or reinfarction, dialysis, stroke) and 30-day and 1-year mortality were evaluated prospectively. The plasma of reintubated patients and matched control patients was tested for CMV deoxyribonucleic acid, and 618 patients were found to be seropositive for CMV (63%). Among these, the risk for reintubation was increased (10% v 4%, p = 0.001). This increase remained significant after correction for confounding factors (odds ratio 2.70, p = 0.003) and was detectable from the third postoperative day throughout the whole postoperative period. Other outcome parameters were not different. Reintubated seropositive patients were more frequently CMV deoxyribonucleic acid-positive than were matched control patients (40% v 8%, p<0.001). CONCLUSIONS: CMV-seropositive patients had an increased risk of reintubation after cardiac surgery, which was associated with reactivations of their CMV infections. Additional studies should determine whether this complication may be prevented by monitoring of latently infected patients and administering antiviral treatment for reactivated CMV infections.

Influence of different electrode belt positions on electrical impedance tomography imaging of regional ventilation: a prospective observational study.

BACKGROUND: Electrical impedance tomography (EIT) is a non-invasive bedside tool which allows an individualized ventilator strategy by monitoring tidal ventilation and lung aeration. EIT can be performed at different cranio-caudal thoracic levels, but data are missing about the optimal belt position. The main goal of this prospective observational study was to evaluate the impact of different electrode layers on tidal impedance variation in relation to global volume changes in order to propose a proper belt position for EIT measurements. METHODS: EIT measurements were performed in 15 mechanically ventilated intensive care patients with the electrode belt at different thoracic layers (L1-L7). All respiratory and hemodynamic parameters were recorded. Blood gas analyses were obtained once at the beginning of EIT examination. Off-line tidal impedance variation/tidal volume (TV/VT) ratio was calculated, and specific patterns of impedance distribution due to automatic and user-defined adjustment of the colour scale for EIT images were identified. RESULTS: TV/VT ratio is the highest at L1. It decreases in caudal direction. At L5, the decrease of TV/VT ratio is significant. We could identify patterns of diaphragmatic interference with ventilation-related impedance changes, which owing to the automatically adjusted colour scales are not obvious in the regularly displayed EIT images. CONCLUSIONS: The clinical usability and plausibility of EIT measurements depend on proper belt position, proper impedance visualisation, correct analysis and data interpretation. When EIT is used to estimate global parameters like VT or changes in end-expiratory lung volume, the best electrode plane is between the 4th and 5th intercostal space. The specific colour coding occasionally suppresses user-relevant information, and manual rescaling of images is necessary to visualise this information.

Preoperative plasma growth-differentiation factor-15 for prediction of acute kidney injury in patients undergoing cardiac surgery.

BACKGROUND: Growth-differentiation factor-15 (GDF-15) is an emerging humoral marker for risk stratification in cardiovascular disease. Cardiac-surgery-associated acute kidney injury (CSA-AKI), an important complication in patients undergoing cardiac surgery, is associated with poor prognosis. The present secondary analysis of an observational cohort study aimed to determine the role of GDF-15 in predicting CSA-AKI compared with the Cleveland-Clinic Acute Renal Failure (CC-ARF) score and a logistic regression model including variables associated with renal dysfunction. METHODS: Preoperative plasma GDF-15 was determined in 1176 consecutive patients undergoing elective cardiac surgery. Patients with chronic kidney disease stage 5 were excluded. AKI was defined according to Kidney-Disease-Improving-Global-Outcomes (KDIGO) - creatinine criteria. The following variables were screened for association with development of postoperative AKI: age, gender, additive Euroscore, serum creatinine, duration of cardiopulmonary bypass, duration of surgery, type of surgery, total circulatory arrest, preoperative hemoglobin, preoperative oxygen-supplemented cerebral oxygen saturation, diabetes mellitus, hemofiltration during ECC, plasma GDF-15, high sensitivity troponin T (hsTNT), and N-terminal prohormone of B-type natriuretic peptide (NTproBNP). RESULTS: There were 258 patients (21.9 %) with AKI (AKI stage 1 (AKI-1), n = 175 (14.9 %); AKI-2, n = 6 (0.5 %); AKI-3, n = 77 (6.5 %)). The incidence of AKI-1 and AKI-3 increased significantly from the lowest to the highest tertiles of GDF-15. In logistic regression, preoperative GDF-15, additive Euroscore, age, plasma creatinine, diabetes mellitus, and duration of cardiopulmonary bypass were independently associated with AKI. Inclusion of GDF-15 in a logistic regression model comprising these variables significantly increased the area under the curve (AUC 0.738 without and 0.750 with GDF-15 included) and the net reclassification ability to predict AKI. Comparably, in receiver operating characteristic analysis the predictive capacity of the CC-ARF score (AUC 0.628) was improved by adding GDF-15 (AUC 0.684) but this score also had lower predictability than the logistic regression model. In random forest analyses the predictive capacity of GDF-15 was especially pronounced in patients with normal plasma creatinine. CONCLUSION: This suggests that preoperative plasma GDF-15 independently predicts postoperative AKI in patients undergoing elective cardiac surgery and is particularly helpful for risk stratification in patients with normal creatinine. TRIAL REGISTRATION: NCT01166360 on July 20, 2010.

Bedside monitoring of ventilation distribution and alveolar inflammation in community-acquired pneumonia.

It is unclear whether bedside monitoring tools such as exhaled nitric oxide measurements (FENO) and electrical impedance tomography (EIT) could help guiding patient management in community-acquired pneumonia (CAP). We hypothesized that exhaled NO would be increased in CAP patients and could be used to assess resolution of inflammation in the course of CAP therapy. Feasibility of multiple-breath (mb) and single-breath (sb) approach has been investigated. EIT was compared with chest X-ray at admission and used to assess whether the inhomogeneous ventilation changes due to treatment. 24 CAP patients were enrolled. Measurements were accomplished at admission (T0: EIT + FENO), after 3 days (T1: FENO) and 5-6 days after admission (T2: EIT + FENO). We computed an EIT distribution index (DEIT), which reflects the uniformity of ventilation. FENO measurements showed a significant decrease in NO after the beginning of antibiotic therapy [p = 0.04 (sb); p = 0.003 (mb)]. Correlation between sb method and mb method was significant (p < 0.001, r = 0.70). EIT detects right-sided and left-sided ventilation disorders due to pneumonia in correspondence to chest X-ray (p < 0.01). EIT images at T2 showed a more homogeneous ventilation distribution in displayed EIT. FENO could be a prospective supplementary tool to describe local lung inflammation as individual trend parameter. EIT could be a suitable supplementary tool to monitor functional lung status in CAP.

A perioperative infusion of sodium bicarbonate does not improve renal function in cardiac surgery patients: a prospective observational cohort study.

INTRODUCTION: Cardiac-surgery-associated-acute-kidney-injury (CSA-AKI) is associated with increased morbidity and mortality. Recent data from patients undergoing on-pump coronary artery bypass grafting suggest that a perioperative infusion of sodium-bicarbonate may decrease the incidence of CSA-AKI. The present study aims to analyze the renoprotective effects of a 24h infusion of sodium-bicarbonate in a large, heterogeneous group of cardiac surgical patients METHODS: Starting in 4/2009, all patients undergoing cardiac surgery at our institution were enrolled in a prospective trial analyzing the relationship between preoperative cerebral oxygen saturation and postoperative organ dysfunction. We used this prospectively sampled data set to perform a cohort analysis of the renoprotective efficiency of a 24h continuous perioperative infusion of sodium-bicarbonate on the incidence of CSA-AKI that was routinely introduced in 7/2009. After exclusion of patients with endstage chronic kidney disease, off-pump procedures, and emergency cases, perioperative changes in renal function were assessed in 280 patients treated with a perioperative infusion of 4 mmol sodium-bicarbonate / kg body weight in comparison with a control cohort of 304 patients enrolled from April to June in this prospective cohort study. RESULTS: With the exception of a lower prevalence of a history of myocardial infarction and a lower preoperative use of intravenous heparin in the bicarbonate-group, no significant between group differences in patient demographics, surgical risk, type, and duration of surgery were observed. Patients in the bicarbonate group had a lower mean arterial blood pressure after induction of anesthesia, needed more fluids, more vasopressors, and a longer treatment time in the high dependency unit. Despite a higher postoperative diuresis, no differences in the incidence of AKI grade 1 to 3 and the need for renal replacement were observed. CONCLUSIONS: Routine perioperative administration of sodium bicarbonate failed to improve postoperative renal function in a large population of cardiac surgical patients.

[Fluid management - which fluid for what type of patients?]. / Perioperatives Flüssigkeitsmanagement - Welches Volumen für welchen Patienten?

There is a renewed discussion about the role of crystalloids and natural as well as synthetic colloids in fluid resuscitation. Based on the currently available evidence the choice of fluid replacement does not influence mortality. However, there is increasing evidence that due to unwarranted organ effects of the specific replacement fluids, individual subgroups of patients may be preferentially treated either with cristalloids or colloids.

Functional residual capacity-guided alveolar recruitment strategy after endotracheal suctioning in cardiac surgery patients.

OBJECTIVE: To determine whether the results of functional residual capacity measurements after endotracheal suctioning could guide the decision to perform an alveolar recruitment maneuver and thus improve lung function. DESIGN: Prospective, randomized, controlled interventional study. SETTING: Intensive care unit of a university hospital. PATIENTS: Fifty-nine mechanically ventilated patients within 2 hrs after elective cardiac surgery without preexisting lung diseases. INTERVENTIONS: Patients received a standard suctioning procedure with disconnection of the ventilator (20 secs, 14 F catheter, 200 cm H2O negative pressure). Prospectively, patients were stratified into two groups by the postsuctioning functional residual capacity value (group A: functional residual capacity >94% of baseline; group B: functional residual capacity <94% of baseline). Both groups were randomized into either a recruitment maneuver (RM) group (positive end-expiratory pressure 15 cm H2O, peak inspiratory pressure 35-40 cm H2O for 30 secs, group RM) or a non-RM group, in which ventilation was resumed without an RM (group NRM), resulting in four groups. MEASUREMENTS AND MAIN RESULTS: Functional residual capacity and arterial blood gases were recorded for up to 1 hr. In addition, distribution of ventilation was measured by means of electrical impedance tomography. The RM had an impact on distribution of ventilation, functional residual capacity, and oxygenation in patients with a decrease of functional residual capacity after suctioning. In contrast, the RM showed no impact on these parameters in patients with no decrease of functional residual capacity after suctioning. CONCLUSIONS: By measurements of functional residual capacity after endotracheal suctioning, patients profiting from a consecutive recruitment maneuver could be identified. Guiding the recruitment strategy on changes of functional residual capacity may improve patient care.

Preoperative cerebral oxygen saturation and clinical outcomes in cardiac surgery.

BACKGROUND: The current study was designed to determine the relation between preoperative cerebral oxygen saturation (Sco2), variables of cardiopulmonary function, mortality, and morbidity in a heterogeneous cohort of cardiac surgery patients. METHODS: In this study, 1,178 consecutive patients scheduled for on-pump surgery were prospectively studied. Preoperative Sco2, demographics, N-terminal pro-B-type natriuretic peptide, high-sensitive troponin T, clinical outcomes, and 30-day and 1-yr mortality were recorded. RESULTS: Median additive EuroSCORE was 5 (range: 0-19). Thirty-day and 1-yr mortality and major morbidity (at least two major complications and/or a high-dependency unit stay of at least 10 days) were 3.5%, 7.7%, and 13.3%, respectively. Median minimal preoperative oxygen supplemented Sco2 (Sco2min-ox) was 64% (range: 15-92%). Sco2min-ox was correlated (all: P value <0.0001) with N-terminal pro-B-type natriuretic peptide (ρ: -0.35), high-sensitive troponin T (ρ: -0.28), hematocrit (ρ: 0.34), glomerular filtration rate (ρ: 0.19), EuroSCORE (τ: 0.20), and left ventricular ejection fraction class (τ: 0.12). Thirty-day nonsurvivors had a lower Sco2min-ox than survivors (median 58% [95% CI, 50.7-62%] vs. 64% [95% CI, 64-65%]; P < 0.0001). Receiver-operating curve analysis of Sco2min-ox and 30-day mortality revealed an area-under-the-curve of 0.71 (95% CI, 0.68-0.73%; P < 0.0001) in the total cohort and an area-under-the-curve of 0.77 (95% CI, 0.69-0.86%; P < 0.0001) in patients with a EuroSCORE more than 10. Logistic regression based on different EuroSCORE categories (0-2; 3-5, 6-10, >10), Sco2min-ox, and duration of cardiopulmonary bypass showed that a Sco2min-ox equal or less than 50% is an independent risk factor for 30-day and 1-yr mortality. CONCLUSIONS: Preoperative Sco2 levels are reflective of the severity of cardiopulmonary dysfunction, associated with short- and long-term mortality and morbidity, and may add to preoperative risk stratification in patients undergoing cardiac surgery.

Relationship between functional residual capacity, respiratory compliance, and oxygenation in patients ventilated after cardiac surgery.

BACKGROUND: Measurement of functional residual capacity (FRC) is now possible at bedside, during mechanical ventilation. OBJECTIVES: To determine the relationship of measured absolute and relative predicted FRC values to oxygenation and respiratory-system compliance, and to identify variables that influence FRC in ventilated patients after cardiac surgery. METHODS: We retrospectively analyzed data from 99 patients ventilated after cardiac surgery. Each patient underwent an alveolar recruitment maneuver and was then ventilated with a positive end-expiratory pressure of 10 cm H2O and a tidal volume of 6-8 mL/kg predicted body weight. We measured quasi-static 2-point compliance of the respiratory system, FRC (with the oxygen-wash-out method), PaO2, and fraction of inspired oxygen (F(I)O2). We indexed the FRC values to predicted FRC reference values from sitting and supine healthy volunteers. RESULTS: Correlation analyses revealed no meaningful association between FRC and PaO2/F(I)O2 (r2 0.20, P < .001). There was a moderate association between absolute FRC and respiratory-system compliance (r2 0.50, P < .001). Indexing the absolute measured FRC values to the predicted FRC values did not improve the correlation. We conducted multiple linear regression analyses of height, weight, age, sex, presence of mild chronic obstructive pulmonary disease, minute volume, and peak inspiratory pressure during ventilation, and revealed weight, minute volume, and peak inspiratory pressure (r2 = 0.65) as independent covariates of FRC. CONCLUSIONS: Indexing the measured FRC values to the predicted supine and sitting FRC values does not improve the association between PaO2/F(I)O2 and respiratory-system compliance. In mechanically ventilated patients after cardiac surgery, FRC is influenced more by the ventilator settings than by physiologic variables (as in spontaneously breathing persons).

Variations in arterial blood pressure are associated with parallel changes in FlowTrac/Vigileo-derived cardiac output measurements: a prospective comparison study.

INTRODUCTION: The reliability of autocalibrated pressure waveform analysis by the FloTrac-Vigileo(R) (FTV) system for the determination of cardiac output in comparison with intermittent pulmonary arterial thermodilution (IPATD) is controversial. The present prospective comparison study was designed to determine the effects of variations in arterial blood pressure on the reliability of the FTV system in patients undergoing coronary artery bypass grafting (CABG). METHODS: Comparative measurements of cardiac output by FTV (derived from a femoral arterial line; software version 1.14) and IPATD were performed in 16 patients undergoing elective CABG in the period before institution of cardiopulmonary bypass. Measurements were performed after induction of anesthesia, after sternotomy, and during five time points during graft preparation. During graft preparation, arterial blood pressure was increased stepwise in intervals of 10 to 15 minutes by infusion of noradrenaline and lowered thereafter to baseline levels. RESULTS: Mean arterial blood pressure was varied between 85 mmHg and 115 mmHg. IPATD cardiac output did not show significant changes during periods with increased arterial pressure either during sternotomy or after pharmacological manipulation. In contrast, FTV cardiac output paralleled changes in arterial blood pressure; i.e. increased significantly if blood pressure was raised and decreased upon return to baseline levels. Mean arterial blood pressure (MAP) and FTV cardiac output were closely correlated (r = 0.63 (95% confidence interval [CI]: 0.49 - 0.74), P < 0.0001) while no correlation between MAP and IPATD cardiac output was observed. Bland-Altman analyses for FTV versus IPATD cardiac output measurements revealed a bias of 0.4 l/min (8.5%) and limits of agreement from 2.1 to -1.3 l/min (42.2 to -25.3%). CONCLUSIONS: Acute variations in arterial blood pressure alter the reliability of the FlowTrac/Vigileo device with the second-generation software. This finding may help to explain the variable results of studies comparing the FTV system with other cardiac output monitoring techniques, questions the usefulness of this device for hemodynamic monitoring of patients undergoing rapid changes in arterial blood pressure, and should be kept in mind when using vasopressors during FTV-guided hemodynamic optimization.

Changes in functional residual capacity during weaning from mechanical ventilation: a pilot study.

BACKGROUND: Reduction of high positive end-expiratory pressure levels and pressure support ventilation (PSV) are frequently used before tracheal extubation in critically ill patients, but the impact of PSV on functional residual capacity (FRC) is unknown. In this study, we sought to detect the changes of FRC and pulmonary function during a weaning protocol in patients ventilated after cardiac surgery. METHODS: The LUFU system (Dräger Medical, Lübeck, Germany) estimates FRC by oxygen washout, a variant of multiple breath nitrogen washout, using a sidestream O(2) analyzer. Postoperative cardiac surgery patients were initially ventilated using biphasic positive airway pressure ventilation (BiPAP) with a positive end-expiratory pressure of 10 mbar. The upper pressure limit was adjusted to deliver a tidal volume of 6-8 mL/kg (BIPAP 10). After 30 min, the upper and lower pressure limits were both reduced by 3 mbar (BIPAP 7). When spontaneous breathing efforts were detected, ventilation mode was switched to continuous positive airway pressure (CPAP) with PSV using the former lower pressure limit as the CPAP level and the corresponding pressure support of the former BIPAP adjustment (CPAP 7_1). Measurements were repeated after 30 min (CPAP 7_2). RESULTS: Ten patients were studied. FRC decreased (BIPAP 10: 3.6 [1.0] L; BIPAP 7: 3.1 [0.9] L; CPAP 7_1: 2.9 [0.9] L; CPAP 7_2: 2.7 [0.6] L [Mean (SD)]; MANOVA: P = 0.017), as did PF ratio (BIPAP 10: 420 [114] mm Hg; BIPAP 7: 405 [110] mm Hg; CPAP 7_1: 353 [70] mm Hg; CPAP 7_2: 340 [70] mm Hg [Mean (SD)]; MANOVA: P = 0.045). PaCO(2) did not change significantly over time (P = 0.221). CONCLUSION: Decreasing FRC during the weaning process after cardiac surgery may, at least in part, be explained by alveolar derecruitment. Whether this variable could help guide a weaning protocol has to be studied further.

Functional residual capacity changes after different endotracheal suctioning methods.

BACKGROUND: Our primary objective was to investigate the effects of three different endotracheal suctioning procedures on functional residual capacity (FRC). METHODS: Using a crossover design, postoperative cardiac surgery patients (n = 20) received three different suctioning methods in randomized order: closed suctioning during pressure-controlled ventilation, closed suctioning during volume-controlled ventilation, and open suctioning. FRC was measured before and 20 min after the intervention. RESULTS AND CONCLUSIONS: FRC is reduced in postcardiac surgery patients after suctioning, regardless of which method is used. Certain patients may have very pronounced changes of FRC. Routine FRC measurements could complement respiratory monitoring to optimize respiratory therapy.

The impact of different step changes of inspiratory fraction of oxygen on functional residual capacity measurements using the oxygen washout technique in ventilated patients.

BACKGROUND: Functional residual capacity (FRC) measurements may help to guide respiratory therapy. Using the oxygen washout technique, FRC can be assessed at bedside during spontaneous breathing. High repeatability, crucial for monitoring, has not been shown in ventilated patients. A large step change of inspiratory fraction of oxygen (FiO(2)) (DeltaFiO(2)) may impede the clinical use in patients ventilated with high FiO(2). We investigated the repeatability of FRC measurements and the impact of different DeltaFiO(2) on this repeatability. METHODS: The LUFU system (Draeger Medical, Luebeck, Germany) estimates FRC by oxygen washout, a variant of multiple-breath-nitrogen-washout during a fast DeltaFiO(2). In 20 postoperative cardiac surgery patients, FRC was measured in duplicate using DeltaFiO(2) of 0.1, 0.2, and 0.6. RESULTS: There were no differences between repeated measurements of FRC, neither using a DeltaFiO(2) of 0.1, 0.2 nor 0.6(Delta0.1: 2.62 L +/- 0.58, 2.62 L +/- 0.59, P = 0.995; Delta0.2: 2.70 L +/- 0.59, 2.66 L +/- 0.56, P = 0.258; Delta0.6: 2.61 L +/- 0.58, 2.59 L +/- 0.58, P = 0,639). Coefficients of variation were 6.6%, 5.6%, and 6.6%, respectively. CONCLUSIONS: FRC can be measured in ventilated patients using the oxygen washout technique with a clinically acceptable repeatability. Repeatability is not significantly influenced whether using a DeltaFiO(2) of 0.1, 0.2, or 0.6.

Lack of agreement between thermodilution and electrical velocimetry cardiac output measurements.

OBJECTIVE: The modified algorithm for the non-invasive determination of cardiac output (CO) by electrical bioimpedance-electrical velocimetry (EV)-has been reported to give reliable results in comparison with echocardiography and pulmonary arterial thermodilution (PA-TD) in patients either before or after cardiac surgery. The present study was designed to determine whether EV-CO measurements reflect intraindividual changes in CO during cardiac surgery. DESIGN: Prospective, observational study. SETTING: Operating room (OR) and intensive care unit (ICU) of a university hospital. PATIENTS: Twenty-nine patients undergoing elective cardiac surgery. INTERVENTIONS: None. MEASUREMENTS: CO was determined simultaneously by PA-TD and EV after induction of anesthesia (t1) and 4.9+/-3.5 h after ICU admission (t2). RESULTS: TD-CO was 3.9+/-1.4 and 5.4+/-1.1 l/min at t1 and t2 (p < 0.0001). EV-CO was 4.3+/-1.1 and 4.9+/-1.5 l/min at t1 and t2 (p = 0.013). Bland-Altman analysis showed a bias of -0.4 l/min and 0.4 l/min and a precision of 3.2 and 3.6 l/min (34.3% and 67.4%) at t1 and t2, respectively. Analysis of the individual pre- to postoperative changes in CO with both methods revealed bidirectional changes in n = 12 patients and unidirectional changes with a difference greater than 50% and less than 50% in n = 9 and n = 8 patients, respectively. CONCLUSIONS: The disagreement between PA-TD and EV-CO measurements after anesthesia induction and after ICU admission, as well as the fact that thoracic bioimpedance did not adequately reflect pre- to postoperative changes in CO, questions the reliability of EV-CO measurements in cardiac surgery patients and contrasts sharply with previous studies.

The metabolic and renal effects of adrenaline and milrinone in patients with myocardial dysfunction after coronary artery bypass grafting.

INTRODUCTION: Myocardial dysfunction necessitating inotropic support is a typical complication after on-pump cardiac surgery. This prospective, randomized pilot study analyzes the metabolic and renal effects of the inotropes adrenaline and milrinone in patients needing inotropic support after coronary artery bypass grafting (CABG). METHODS: During an 18-month period, 251 patients were screened for low cardiac output upon intensive care unit (ICU) admission after elective, isolated CABG surgery. Patients presenting with a cardiac index (CI) of less than 2.2 liters/minute per square meter upon ICU admission - despite adequate mean arterial (titrated with noradrenaline or sodium nitroprusside) and filling pressures - were randomly assigned to 14-hour treatment with adrenaline (n = 7) or milrinone (n = 11) to achieve a CI of greater than 3.0 liters/minute per square meter. Twenty patients not needing inotropes served as controls. Hemodynamics, plasma lactate, pyruvate, glucose, acid-base status, insulin requirements, the urinary excretion of alpha-1-microglobuline, and creatinine clearance were determined during the treatment period, and cystatin-C levels were determined up to 48 hours after surgery (follow-up period). RESULTS: After two to four hours after ICU admission, the target CI was achieved in both intervention groups and maintained during the observation period. Plasma lactate, pyruvate, the lactate/pyruvate ratio, plasma glucose, and insulin doses were higher (p < 0.05) in the adrenaline-treated patients than during milrinone or control conditions. The urinary excretion of alpha-1-microglobuline was higher in the adrenaline than in the control group 6 to 14 hours after admission (p < 0.05). No between-group differences were observed in creatinine clearance, whereas plasma cystatin-C levels were significantly higher in the adrenaline than in the milrinone or the control group after 48 hours (p < 0.05). CONCLUSION: This suggests that the use of adrenaline for the treatment of postoperative myocardial dysfunction - in contrast to treatment with the PDE-III inhibitor milrinone - is associated with unwarranted metabolic and renal effects.

A single prophylactic dose of pentoxifylline reduces high dependency unit time in cardiac surgery - a prospective randomized and controlled study.

BACKGROUND: The pathogenesis of the post cardiopulmonary bypass (CPB) organ dysfunction syndrome is complex, with inflammation being an important component. The purpose of this prospective, randomized and controlled study was to evaluate the effect of a single dose of pentoxifylline (PTX) prior to CPB on high dependency unit time. MATERIALS AND METHODS: We studied 39 patients undergoing aorto-coronary bypass surgery with CPB. Patients received either 5 mg kg(-1) PTX after induction of anaesthesia or saline as placebo. Haemodynamics, parameters of pulmonary function and plasma levels of tumour necrosis factor alpha (TNFalpha) and C-reactive protein (CRP) were measured after the induction of anaesthesia (pre-CPB) and after weaning from CPB (post-CPB), 1 h after the admission to the intensive care unit (ICU) and on the morning of the first postoperative day (1 POD), respectively. In addition, ventilation time and the high dependency unit time, i.e. the time till transferral to a peripheral ward, were documented. RESULTS: Patients in the PTX group had lower TNFalpha values (6.3 ng ml(-1) (4/8.2) vs 9.1 ng ml(-1) (6.5/13.7)) (median (25%/75%), p=0.021), lower systolic (28+/-7 mm Hg vs 35 +/- 9 mm Hg, mean+/-SD, p=0.011) and mean pulmonary artery pressures (21+/-5 vs 26+/-6 mm Hg, p=0.017) after admission to the ICU than control patients. Haemodynamics and pulmonary function parameters did not differ. There was a trend towards earlier weaning from the respirator in the PTX group (10.0+/-3.5 h) (min/max: 4/16; confidence interval (ConF): 1.8 h) than the control group (12.3+/-4.2 h) (min/max: 5-24; ConI: 2.4 h) (p=0.077). Patients treated with PTX could be transferred to a peripheral ward about 24 h earlier than control patients (95+/-35 h, min/max: 32/190 h; ConI: 17 h; 119+/-29 h, min/max: 66/165 h; ConI: 16 h) respectively; p=0.037). CONCLUSION(S): A single dose of PTX prior to CPB was able to reduce plasma levels of TNFalpha. In this descriptive study, there was a trend towards reduced duration of ventilation and the high dependency unit time, i.e. the time till transferral to a peripheral ward was shortened.

The accuracy of the oxygen washout technique for functional residual capacity assessment during spontaneous breathing.

BACKGROUND: Measurement of functional residual capacity (FRC) is of considerable interest for monitoring patients with lung injury. The lack of instruments has impeded routine bedside FRC measurement. Recently, a simple automated method for FRC assessment by O2 washout has been introduced. We designed this study to evaluate the accuracy of FRC measurement using the O2 washout technique. METHODS: The LUFU system (Draeger, Luebeck, Germany) estimates FRC by O2 washout, a variant of multiple breath nitrogen washout. This technique uses a sidestream O2-analyzer to calculate FRC from end-inspired and end-expired O2 concentrations during fast changes of Fio2. We measured FRC in 23 healthy, spontaneously breathing volunteers in the sitting position using three techniques: 1) helium dilution (FRC-He), 2) body plethysmography (FRC-bp), 3) oxygen washout (FRC-O2). RESULTS: FRC-O2 (mean 4.1 +/- 1.1 L, range 2.4-6.9 L) corresponds with FRC-He (mean 4.0 +/- 1.0 L, range 2.4-6.2 L; bias of FRC-O2: -0.2 +/- 0.4 L) and FRC-bp (mean 4.2 +/- 1.0 L, range 2.8-6.1 L; bias of FRC-O2: 0.1 +/- 0.6 L). CONCLUSIONS: The bias and precision of the O2 washout technique using the LUFU system were clinically acceptable when compared with FRC-He and FRC-bp for FRC assessment in spontaneously breathing volunteers.

The suitability of EIT to estimate EELV in a clinical trial compared to oxygen wash-in/wash-out technique.

INTRODUCTION: Open endotracheal suctioning procedure (OSP) and recruitment manoeuvre (RM) are known to induce severe alterations of end-expiratory lung volume (EELV). We hypothesised that EIT lung volumes lack clinical validity. We studied the suitability of EIT to estimate EELV compared to oxygen wash-in/wash-out technique. METHODS: Fifty-four postoperative cardiac surgery patients were enrolled and received standardized ventilation and OSP. Patients were randomized into two groups receiving either RM after suctioning (group RM) or no RM (group NRM). Measurements were conducted at the following time points: Baseline (T1), after suctioning (T2), after RM or NRM (T3), and 15 and 30 min after T3 (T4 and T5). We measured EELV using the oxygen wash-in/wash-out technique (EELVO2) and computed EELV from EIT (EELVEIT) by the following formula: EELVEITTx,y…=EELVO2+ΔEELI×VT/ΔZ. EELVEIT values were compared with EELVO2 using Bland-Altman analysis and Pearson correlation. RESULTS: Limits of agreement ranged from -0.83 to 1.31 l. Pearson correlation revealed significant results. There was no significant impact of RM or NRM on EELVO2-EELVEIT relationship (p=0.21; p=0.23). DISCUSSION: During typical routine respiratory manoeuvres like endotracheal suctioning or alveolar recruitment, EELV cannot be estimated by EIT with reasonable accuracy.

Non-invasive cerebral oxygenation reflects mixed venous oxygen saturation during the varying haemodynamic conditions in patients undergoing transapical transcatheter aortic valve implantation.

Transapical transcatheter aortic valve implantation (TA-TAVI) is increasingly used to treat aortic valve stenosis in high-risk patients. Mixed venous oxygen saturation (SvO(2)) is still the 'gold standard' for the determination of the systemic oxygen delivery to consumption ratio in cardiac surgery patients. Recent data suggest that regional cerebral oxygen saturation (rScO(2)) determined by near-infrared spectroscopy is closely related to SvO(2). The present study compares rScO(2) and SvO(2) in patients undergoing TA-TAVI. n = 20 cardiac surgery patients scheduled for TA-TAVI were enrolled in this prospective observational study. SvO(2) and rScO(2) were determined at predefined time points during the procedure. Correlation and Bland-Altman analysis of the complete data set showed a correlation coefficient of r(2 )= 0.7 between rScO(2) and SvO(2) (P < 0.0001), a mean difference (bias) of 5.8 with limits of agreement (1.96 SD) of -6.8 to 18.3% and a percentage error of 17.5%. At all predefined time points correlation was moderate (r(2 )= 0.50) to close (r = 0.84), and the percentage error was <24%. RScO(2) determined by near-infrared spectroscopy is correlated to SvO(2) during varying haemodynamic conditions in patients undergoing TA-TAVI. This suggests that rScO(2) is reflective not only of the cerebral, but also of the systemic oxygen balance.

Low preoperative cerebral oxygen saturation is associated with longer time to extubation during fast-track cardiac anaesthesia.

OBJECTIVES: Fast-track cardiac anaesthesia programs aiming at early tracheal extubation have not only been linked to a decrease in intensive care unit and hospital length of stay but also to a decrease in morbidity and mortality as well as a containment of rising medical costs. General recommendations for the inclusion criteria concerning fast-track programs are not available. METHODS: The present study determined the factors influencing the time to extubation in patients undergoing a newly implemented fast-track protocol. Seventy-nine patients were retrospectively studied. Successful fast track was defined as time to extubation within 75 min after admission to ICU. RESULTS: Sixty patients fulfilled the successful fast-track criteria with a mean time to extubation of 43.9 min (range 15-75 min). Nineteen patients needed more than 75 min to be weaned from the respirator with a mean time to extubation of 135 min (range 90-320 min). Analysis of pre- and intraoperative factors revealed that these groups differed only with respect to preoperative cerebral oxygen saturation levels: 67.7 ± 5.2 versus 60.8 ± 7.4%. CONCLUSIONS: Cerebral oxygen saturation assessment prior to cardiac surgery is significantly related to time to extubation and may thus be used to stratify candidates in fast-track programs.