Late pharmacologic conditioning with volatile anesthetics after cardiac surgery.

INTRODUCTION: The aim of this randomized controlled trial was to investigate whether volatile anesthetics used for postoperative sedation have any beneficial effects on myocardial injury in cardiac surgery patients after on-pump valve replacement. METHODS: Anesthesia was performed with propofol. After arrival in the intensive care unit (ICU), 117 patients were randomized to be sedated for at least 4 hours with either propofol or sevoflurane. Sevoflurane was administered by using the anesthetic-conserving device. Troponin T, creatine kinase, creatine kinase from heart muscle tissue, myoglobin, and oxygenation index were determined on arrival at the ICU, 4 hours after sedation, and in the morning of the first postoperative day (POD1). Primary end points were cardiac injury markers on POD1. As secondary end points oxygenation, postoperative pulmonary complications, and ICU and hospital stay were documented. RESULTS: Fifty-six patients were analyzed in the propofol arm, and 46 patients in the sevoflurane arm. Treatment groups were comparable with regard to patient demographics and intraoperative characteristics. Concentration of troponin T as the most sensitive marker for myocardial injury at POD1 was significantly lower in the sevoflurane group compared with the propofol group (unadjusted difference, -0.4; 95% CI, -0.7 to -0.1; P < 0.01; adjusted difference, -0.2; 95% CI, -0.4 to -0.02; P = 0.03, respectively). CONCLUSIONS: The data presented in this investigation indicate that late postconditioning with the volatile anesthetic sevoflurane might mediate cardiac protection, even with a late, brief, and low-dose application. TRIAL REGISTRATION: ClinicalTrials.gov: NCT00924222.

The revised digital transcutaneous PCO2/SpO2 ear sensor is a reliable noninvasive monitoring tool in patients after cardiac surgery.

OBJECTIVE: The aim of this study was to validate the revised SenTec V-Sign 2 sensor (SenTec AG, Therwil, Switzerland) for combined noninvasive continuous assessment of pulse rate, pulse oximetry (SpO(2)), and transcutaneous carbon dioxide tension (PtcCO(2)) in adults after cardiac surgery. DESIGN: A prospective clinical study. SETTING: A single-center university hospital. PARTICIPANTS: Twenty adult patients aged 36 to 84 years after cardiac surgery. INTERVENTIONS: SpO(2) and PtcCO(2) values of three V-Sign 2 sensors (SenTec AG) attached at the earlobe, forehead, and cheek and SpO(2) values of the Nellcor Durasensor (Model DS-100A; Nellcor Puritan Bennett Inc, Pleasanton, CA) were compared with simultaneous measurements of blood gases and end-expiratory carbon dioxide. MEASUREMENTS AND MAIN RESULTS: Measurements were performed during periods of hyper-, normo-, and hypocapnia and then at 30-minute intervals up to 5 hours. Bland-Altman analysis and simple regression analysis were used. RESULTS: The detection failures for PtcCO(2) were 0.3% to 1.3%, for SpO(2) 10% to 25%, and for pulse rate 5% to 10%. The V-Sign 2 earlobe sensor provided the best results. The mean bias and limits of agreement for PtcCO(2ear) and PaCO(2) were 1.1 and -3.4/+5.5 mmHg. The drift of PtcCO(2) was negligible at all locations. The mean bias and limits of agreement of V-Sign SpO(2ear) and SaO(2), as well as V-Sign pulse rate and the electrocardiogram, were -1.7% and -6.8/+3.9% and 1.2 beats/min and -3.3/+5.8 beats/min. End-expiratory carbon dioxide showed a weak correlation with PaCO(2) (r(2) = 0.47). CONCLUSIONS: Transcutaneous capnometry using the revised V-Sign 2 sensor at the earlobe is a reliable monitoring tool during the recovery period of patients after cardiac surgery. This approach has the potential to reduce the number of arterial blood gas samples.

Clinical review: practical recommendations on the management of perioperative heart failure in cardiac surgery.

Acute cardiovascular dysfunction occurs perioperatively in more than 20% of cardiosurgical patients, yet current acute heart failure (HF) classification is not applicable to this period. Indicators of major perioperative risk include unstable coronary syndromes, decompensated HF, significant arrhythmias and valvular disease. Clinical risk factors include history of heart disease, compensated HF, cerebrovascular disease, presence of diabetes mellitus, renal insufficiency and high-risk surgery. EuroSCORE reliably predicts perioperative cardiovascular alteration in patients aged less than 80 years. Preoperative B-type natriuretic peptide level is an additional risk stratification factor. Aggressively preserving heart function during cardiosurgery is a major goal. Volatile anaesthetics and levosimendan seem to be promising cardioprotective agents, but large trials are still needed to assess the best cardioprotective agent(s) and optimal protocol(s). The aim of monitoring is early detection and assessment of mechanisms of perioperative cardiovascular dysfunction. Ideally, volume status should be assessed by 'dynamic' measurement of haemodynamic parameters. Assess heart function first by echocardiography, then using a pulmonary artery catheter (especially in right heart dysfunction). If volaemia and heart function are in the normal range, cardiovascular dysfunction is very likely related to vascular dysfunction. In treating myocardial dysfunction, consider the following options, either alone or in combination: low-to-moderate doses of dobutamine and epinephrine, milrinone or levosimendan. In vasoplegia-induced hypotension, use norepinephrine to maintain adequate perfusion pressure. Exclude hypovolaemia in patients under vasopressors, through repeated volume assessments. Optimal perioperative use of inotropes/vasopressors in cardiosurgery remains controversial, and further large multinational studies are needed. Cardiosurgical perioperative classification of cardiac impairment should be based on time of occurrence (precardiotomy, failure to wean, postcardiotomy) and haemodynamic severity of the patient's condition (crash and burn, deteriorating fast, stable but inotrope dependent). In heart dysfunction with suspected coronary hypoperfusion, an intra-aortic balloon pump is highly recommended. A ventricular assist device should be considered before end organ dysfunction becomes evident. Extra-corporeal membrane oxygenation is an elegant solution as a bridge to recovery and/or decision making. This paper offers practical recommendations for management of perioperative HF in cardiosurgery based on European experts' opinion. It also emphasizes the need for large surveys and studies to assess the optimal way to manage perioperative HF in cardiac surgery.

A novel operator-independent algorithm for cardiac output measurements based on three-dimensional transoesophageal colour Doppler echocardiography.

AIMS: Cardiac output (CO) measurements from three-dimensional (3D) trans-mitral Doppler echocardiography are prone to error as manual selection of the region of interest (i.e. the site of measurement) is required. We newly developed an automated, user-independent algorithm to select the site of colour Doppler CO measurement. We aimed to validate this new method by benchmarking it against thermodilution, the current gold standard for CO measurements. METHODS AND RESULTS: Transoesophageal colour 3D Doppler echocardiographic studies were obtained from 15 patients who also had received a pulmonary catheter for invasive CO measurements. Trans-mitral flow was determined using a novel operator-independent algorithm to automatically select the optimal site of measurement. The operator-independent CO measurements were referenced against thermodilution. A good correlation was found between operator-independent Doppler flow computations and thermodilution with a mean bias of 0.09 L/min, standard deviation of bias 1.3 L/min, and a 26% error (2 SD/mean CO). Mean CO was 4.94 L/min (range 3.10-7.10 L/min). CONCLUSION: Our findings demonstrate that CO computation from transoesophageal colour 3D Doppler echo can be automated concerning the site of velocity measurement. Our operator-independent algorithm provides an objective and reproducible alternative to thermodilution.

Comparison of spectral entropy and bispectral index electroencephalography in coronary artery bypass graft surgery.

OBJECTIVE: The study's aim was to compare response entropy (RE) and state entropy (SE) with bispectral index (BIS) electroencephalography (EEG) as an alternative cerebral monitoring tool in patients scheduled for coronary artery bypass graft surgery. DESIGN: Prospective, observational single-center study. SETTING: University hospital. PARTICIPANTS: Thirty patients undergoing coronary artery bypass graft surgery receiving remifentanil-propofol anesthesia. INTERVENTIONS: Surgery was performed with cardiopulmonary bypass (CPB) and cardiac arrest in 15 patients, with CPB without cardiac arrest in 9 patients and without CPB in 6 patients. MEASUREMENTS AND MAIN RESULTS: RE, SE, BIS, burst suppression ratio (BSR), and frontal electromyography (f-EMG) were detected simultaneously. RE and SE compared favorably with BIS and their correlations were strong (r(2) = 0.6, r(2) = 0.55, respectively). The mean bias of RE and BIS was -1.8, but limits of agreement were high (+20.5/-24.1). RE and SE tended to be lower than the BIS values in the CPB subgroups. The detection of BSR was similar with RE and SE and the BIS. A strong correlation existed between BIS and f-EMG (r(2) = 0.62) in contrast to RE (r(2) = 0.45) and SE (r(2) =0.39). BIS monitoring was significantly more disturbed than RE and SE with 9.1% +/-10.9% and 0.1% +/- 0.2% of the total anesthesia time, respectively. Neither implicit nor explicit memory was shown. CONCLUSION: RE and SE are comparable with the BIS but showed significantly less interference from f-EMG and superior resistance against artifacts. Thus, spectral entropy is more suitable than the BIS during propofol-remifentanil anesthesia in cardiac surgery patients.

Anesthetic-induced improvement of the inflammatory response to one-lung ventilation.

BACKGROUND: Although one-lung ventilation (OLV) has become an established procedure during thoracic surgery, sparse data exist about inflammatory alterations in the deflated, reventilated lung. The aim of this study was to prospectively investigate the effect of OLV on the pulmonary inflammatory response and to assess possible immunomodulatory effects of the anesthetics propofol and sevoflurane. METHODS: Fifty-four adults undergoing thoracic surgery with OLV were randomly assigned to receive either anesthesia with intravenously applied propofol or the volatile anesthetic sevoflurane. A bronchoalveolar lavage was performed before and after OLV on the lung side undergoing surgery. Inflammatory mediators (tumor necrosis factor alpha, interleukin 1beta, interleukin 6, interleukin 8, monocyte chemoattractant protein 1) and cells were analyzed in lavage fluid as the primary endpoint. The clinical outcome determined by postoperative adverse events was assessed as the secondary endpoint. RESULTS: The increase of inflammatory mediators on OLV was significantly less pronounced in the sevoflurane group. No difference in neutrophil recruitment was found between the groups. A positive correlation between neutrophils and mediators was demonstrated in the propofol group, whereas this correlation was missing in the sevoflurane group. The number of composite adverse events was significantly lower in the sevoflurane group. CONCLUSIONS: This prospective, randomized clinical study suggests an immunomodulatory role for the volatile anesthetic sevoflurane in patients undergoing OLV for thoracic surgery with significant reduction of inflammatory mediators and a significantly better clinical outcome (defined by postoperative adverse events) during sevoflurane anesthesia.

Presentation and outcome of critically ill medical and cardiac-surgery patients with acute heart failure.

BACKGROUND: The aim of the study was to investigate presentation and outcome of consecutive acute heart failure (AHF) patients admitted to the intensive care unit (ICU) including also patients undergoing cardiac surgery, thereby providing comparative information on all critically ill AHF subgroups. METHODS: The prospective observational study with 6-month follow up was performed in the cardio-thoracic and the medical ICU of a university hospital. AHF was defined according to the European Society of Cardiology guidelines. Univariate Cox regression was used to calculate hazard ratio (HR) and 95% confidence intervals (CI) for risk factors. RESULTS: A total of 192 patients fulfilled the AHF criteria, of whom 86 and 24 underwent elective and emergency cardiac surgery, respectively. The remaining 82 medical patients had no surgical interventions. Cardiogenic shock was diagnosed in 32% of all patients and was the most common AHF presentation. Medical, elective surgery and emergency surgery AHF patients had a mortality at 30 days of 31%, 4.7% and 22% (<0.05) and at 180 days of 42%, 6.1% and 23% (<0.05), respectively. While the presence of cardiogenic shock was associated with a poor outcome (HR 1.8, CI 1.0-3.0; p=0.04), post-operative cardiac stunning had a good prognosis (HR 0.06, CI 0.01-0.47; p<0.01). Mortality worsened when infections (HR 2.8, CI 1.5-5.7; p<0.01) or renal dysfunction (HR 4.4, CI 2.2-8.4, p<0.01) were present on ICU admission. CONCLUSIONS: Medical patients, patients undergoing elective cardiac surgery and patients requiring emergency cardiac surgery are three distinct AHF-subpopulations. Co-morbidities and surgical treatment options affect long-term outcome.

Impact of minimal increases in serum creatinine on outcome in patients after cardiothoracic surgery: do we have to revise current definitions of acute renal failure?

OBJECTIVE: Traditional cutoff values of serum creatinine considered to define postoperative acute renal failure have been challenged recently. In a previous investigation we demonstrated that minimal changes in serum creatinine concentration were associated with a substantial decrease in survival after cardiac surgery. In this investigation, we assessed the impact of minimal absolute increases in serum creatinine in a second institution, and we analyzed whether relative changes, as in the RIFLE classification and, partially, in Acute Kidney Injury Network (AKIN) classification, confer a different prognostic potential. DESIGN: Prospective analysis. SETTING: University hospital. PATIENTS: All consecutive patients undergoing cardiac surgery in the University Hospital of Zurich (Center USZ) over a 46-month period. INTERVENTIONS: Patients were prospectively documented. We analyzed maximal changes in serum creatinine in the first 48 hrs postoperatively (DeltaCrea) regarding death within 30 days. Results were compared with those of the University Hospital Vienna (Center AKH). Moreover, the prognostic potential of DeltaCrea within 48 hrs vs. serum creatinine elements according to RIFLE and AKIN classifications was assessed. MEASUREMENTS AND MAIN RESULTS: A total of 3,123 patients were evaluated from USZ. The majority of patients had decreased postoperative serum creatinine values (negative DeltaCrea) and the lowest mortality (1.8%). Minimal increases, [0, 0.5) mg x dL(-1), were associated with a more than doubled mortality in both centers (5%/6%). Mortality, according to RIFLE and AKIN classifications for both populations combined, was as follows: 7,023 (3.6%), 160 (29%), 43 (19%), and 15 (33%) for RIFLE Normal, Risk, Injury, and Failure; 6,644 (2.8), 463 (16.4), 3 (66.7), and 131 (1.8) for AKIN stage 0, 1, 2, and 3. CONCLUSIONS: Measuring repeat serum creatinine concentrations within 48 hrs and determining DeltaCrea were the most effective discrimination method to find patients at risk for adverse postoperative outcome after cardiac surgery, better than application of this sole criterion to the RIFLE (least discriminatory) or the AKIN classification.

Continuous extrapleural infusion of ropivacaine 0.2% after cardiovascular surgery via the lateral thoracotomy approach.

OBJECTIVE: The pharmacokinetics of ropivacaine 0.2% were evaluated during a 48-hour continuous extrapleural infusion with 2 different infusion rates in patients undergoing cardiovascular surgery. The hypotheses that no toxic plasma concentrations of ropivacaine would be reached and that proportionality exists among plasma concentrations and dosage used were tested. DESIGN: A prospective, randomized, nonblinded study. SETTING: The investigation was performed as a single-center study in the Division of Cardiovascular Anesthesia, University Hospital of Zurich, in Switzerland. PARTICIPANTS: Seventeen consenting adults scheduled for elective cardiovascular surgery, with or without extracorporeal bypass, via the lateral thoracotomy approach were enrolled. INTERVENTIONS: For postoperative pain relief, patients were randomly assigned to receive continuous extrapleural infusion of ropivacaine 0.2% at a rate of either 6 or 9 mL/h over 48 hours. MEASUREMENTS AND MAIN RESULTS: Plasma concentrations of ropivacaine reached toxic levels (>2.2 mg/L) in 25% of cases. No proportionality of plasma concentrations of ropivacaine existed when the 2 dosing regimens were compared. CONCLUSIONS: Plasma concentrations of ropivacaine, administered at the given dose and rates during continuous extrapleural infusion, are unpredictable and may reach toxic levels in patients undergoing major cardiothoracic surgery.

Accuracy of continuous central venous oxygen saturation monitoring in patients undergoing cardiac surgery.

OBJECTIVE: Continuous assessment of central venous oxygen saturation (S(cevox)O(2)) with the CeVOX device (Pulsion Medical Systems, Munich, Germany) was evaluated against central venous oxygen saturation (S(cv)O(2)) determined by co-oximetry. METHODS: In 20 cardiac surgical patients, a CeVOX fiberoptic probe was introduced into a standard central venous catheter placed in the right internal jugular vein and advanced 2-3 cm beyond the catheter tip. After in vivo calibration of the probe, S(cevox)O(2), S(cv)O(2), mixed venous oxygen saturation (S(mv)O(2)) haemoglobin (Hb), body temperature, heart rate, central venous and mean arterial pressure, and cardiac index were assessed simultaneously at 30 min intervals during surgery and at 60 min intervals during recovery in the intensive care unit. Agreement between S(cevox)O(2), and S(cv)O(2) was determined by Bland-Altman analysis. Simple regression analysis was used to assess the correlation of S(cevox)O(2), and S(cv)O(2) to Hb, body temperature and haemodynamic parameters. RESULTS: Values of S(cevox)O(2) and S(cv)O(2) (84 data pairs during surgery and 106 in the intensive care unit) ranged between 45-89% and 43-90%, respectively. Mean bias and limits of agreement of S(cevox)O(2) and S(cv)O(2) were -0.9 (-7.9/+6.1)% during surgery and -1.2 (-10.5/+8.1)% in the intensive care unit. In 37.9% of all measured data pairs, the difference between S(cevox)O(2) and S(cv)O(2) was beyond clinically acceptable limits (> or =1 s.d.). Mean bias was significantly influenced by cardiac index. Sensitivity and specificity of S(cevox)O(2) to detect substantial (> or =1 s.d.) changes in S(cv)O(2) were 89 and 82%, respectively. CONCLUSIONS: In adult patients during and after cardiac surgery, the current version of the CeVOX device might not be the tool to replace S(cv)O(2) determined by co-oxymetry, although sensitivity and specificity of S(cevox)O(2 )to predict substantial changes in S(cv)O(2) were acceptable.

Oxidative stress precedes peak systemic inflammatory response in pediatric patients undergoing cardiopulmonary bypass operation.

Oxidative stress seems to contribute to cardiopulmonary bypass (CPB)-related postoperative complications. Pediatric patients are particularly prone to these complications. With this in mind, we measured oxidative stress markers in blood plasma of 20 children undergoing elective heart surgery before, during, and up to 48 h after cessation of CPB, along with inflammatory parameters and full analysis of iron status. Ascorbate levels were decreased by approximately 50% (P < 0.001) at the time of aorta cross-clamp removal (or pump switch-off in 4 patients with partial CPB), and associated with corresponding increases in dehydroascorbate (P < 0.001, r = -0.80) and malondialdehyde (P < 0.01, r = -0.59). In contrast to the immediate oxidative response, peak levels of IL-6 and IL-8 were not observed until 3-12 h after CPB cessation. The early loss of ascorbate correlated with duration of CPB (P < 0.002, r = 0.72), plasma hemoglobin after cross-clamp removal (P < 0.001, r = 0.70), and IL-6 and IL-8 levels at 24 and 48 h after CPB (P < 0.01), but not with postoperative lactate levels, strongly suggesting that hemolysis, and not inflammation or ischemia, was the main cause of early oxidative stress. The correlation of ventilation time with early changes in ascorbate (P < 0.02, r = 0.55), plasma hemoglobin (P < 0.01, r = 0.60), and malondialdehyde (P < 0.02, r = 0.54) suggests that hemolysis-induced oxidative stress may be an underlying cause of CPB-associated pulmonary dysfunction. Optimization of surgical procedures or therapeutic intervention that minimize hemolysis (e.g., off-pump surgery) or the resultant oxidative stress (e.g., antioxidant treatment) should be considered as possible strategies to lower the rate of postoperative complications in pediatric CPB.

Early postoperative arrhythmias after cardiac operation in children.

BACKGROUND: Arrhythmias are a recognized complication of cardiac operations. However, little is known about the incidence, treatment, and risk factors for early postoperative arrhythmias in children after cardiac operations. METHODS: Diagnosis and treatment of early postoperative arrhythmias were prospectively analyzed in an intensive care unit in 100 consecutive children with a median age of 17 months (range, 1 day to 191 months) who had undergone cardiac operation. Patients were grouped in three different categories of surgical complexity. RESULTS: During a median postoperative time of 1 day (range, 0 to 15 days), 64 critical arrhythmias occurred in 48 patients. Arrhythmias consisted of sinus bradycardia in 30, atrioventricular block II to III in 7, supraventricular tachyarrhythmias in 14, and premature complexes in 13 instances. Treatment of 52 arrhythmias was successful and included pacing in 41, intravenous amiodarone in 8, body cooling in 5, overdrive pacing in 3, and electrolyte correction in 2 cases, with more than one treatment modality in 8 cases. Risk factors for arrhythmias were lower body weight (p < 0.05), longer cardiopulmonary bypass duration (p < 0.05), and a category of higher surgical complexity (p < 0.001). CONCLUSIONS: Early postoperative arrhythmias occur frequently after cardiac operations in children. Sinus bradycardia, atrioventricular block II to III, and supraventricular tachyarrhythmias are the most frequent arrhythmias, which, however, can be treated effectively by means of temporary pacing, cooling, and antiarrhythmic drug therapy. Lower body weight, longer cardiopulmonary bypass duration, and a higher surgical complexity are risk factors for early postoperative arrhythmias.

Spindle activity in children during cardiac surgery and hypothermic cardiopulmonary bypass.

Hypothermia has marked effects on the electrical activity of the brain, which has been shown in animals as well as in humans. The aim of this study was to investigate EEG spindle activity in children during cardiac surgery and hypothermic cardiopulmonary bypass. The authors obtained intraoperative 21-channel EEG recordings in 36 children (mean age, 22 months; range, 6 days to 69 months) with congenital heart disease. Bipolar EEG derivations were analyzed visually for rhythmic spindle activity based on morphology, frequency, duration, and amplitude. Linear regression analysis for duration, frequency, and amplitude versus rectal temperature was performed in each individual. Spindle activity was observed in 17 children (16 children < 12 months of age). Progressive slowing of spindle frequency with decreasing rectal temperature was found (mean decrease, 0.54 +/- 0.31 Hz/ degrees C). Spindle duration increased on average by 0.69 +/- 0.39 second/ degrees C during cooling procedures. Spindle amplitude did not show any correlation to changes in rectal temperature. The current study demonstrates spindle activity during hypothermic cardiopulmonary bypass with temperature-dependent spindle modifications of frequency and duration. Although the temperature-dependent changes in this study confirm temperature coefficients of other EEG studies, the reasons for the clear age relationship and the "nature" of these spindles remain unknown.

Regional citrate anticoagulation using a citrate-based substitution solution for continuous venovenous hemofiltration in cardiac surgery patients.

OBJECTIVE: To evaluate the feasibility, efficacy, safety and side effects of routinely performed continuous venovenous hemofiltration (CVVH) with regional citrate anticoagulation using a citrate-containing substitution solution as compared with conventional systemic low-dose unfractionated heparin-anticoagulation in postoperative cardiac surgery patients. DESIGN/SETTING: Database review of all patients on CVVH during a three-year period at a cardiovascular intensive care unit of a tertiary referring university hospital. PATIENTS: Patients who had undergone cardiac surgery with acute or chronic renal failure were studied. Thirty-seven citrate CVVH courses in 31 patients (January to November 2000) and 59 heparin CVVH courses in 50 patients (1998 and 1999) had been undertaken postoperatively. Indications for hemofiltration were acute renal failure in 24 and chronic renal failure in 7 of the citrate patients, and acute renal failure in 44 and chronic renal failure in 6 of the heparin patients. INTERVENTIONS: CVVH with either regional citrate anticoagulation using a custom-made citrate-based substitution solution or unfractionated heparin anticoagulation. MEASUREMENTS: The following parameters were measured: median filtration time, hemofilters used per day, differences in creatinine and blood urea levels as opposed to baseline, blood loss within the first 24 h of hemofiltration, incidence of bleeding-related resternotomies, acidosis, and alkalosis. RESULTS: No significant differences in any of the measured parameters were registered. No serious electrolyte imbalance was observed in either group. Furthermore, the two groups did not differ in terms of mortality, duration of stay in the intensive care unit or in hospital, and restoration rate of normal renal function. CONCLUSIONS: We conclude that citrate-based regional anticoagulation is effective, safe and easy to use in CVVH following cardiac surgery and might become the first choice for anticoagulation in patients in whom the application of systemic heparin is contraindicated.

The impact of infections on critically ill acute heart failure patients: an observational study.

BACKGROUND: Hospitalised patients with acute heart failure (AHF) suffer from a high morbidity and mortality, which might, at least partly, be influenced by concomitant infections. The aim of this observational study was to investigate the impact of infections on the clinical course of critically ill patients with AHF, both present on intensive care unit (ICU) admission and acquired during the ICU stay. METHODS: From 178 consecutive AHF patients, 76 were treated medically and 21 required emergency cardiac surgery. The remaining 81 patients, who underwent elective cardiac surgery, were excluded from the assessment of infections on ICU admission, but were included in the analysis of nosocomial infections during the ICU stay. RESULTS: A total of 16% of patients (16/97) had infections on ICU admission. These patients had longer ICU (6 vs. 3 days, p = 0.04) and hospital (19 vs. 11 days, p = 0.04) stays than patients without infections. Although not statistically significant, there was a trend for increased mortality at 30 days (44% vs. 24%, p = 0.13) and 6 months (57% vs. 31%, p = 0.13) in AHF patients with infections on ICU admission. Infection complications during the ICU stay occurred in 17% (30/178) of AHF patients and significantly increased their mortality at 30 days (33% vs. 14%, p = 0.02) and 6 months (41% vs. 18%, p = 0.02). CONCLUSIONS: In this observational study, infections present on ICU admission or occurring during the ICU stay had a negative impact on the morbidity and mortality of critically ill patients with AHF. Future studies are needed to gain a better understanding of the interactions between heart failure and infections, as a better knowledge of this field may have an important therapeutic potential.

Accuracy of a novel approach to measuring arterial thermodilution cardiac output during intra-aortic counterpulsation.

OBJECTIVE: To assess the agreement between a novel approach of arterial and the pulmonary artery bolus thermodilution for measuring cardiac output in critically ill patients during aortic counterpulsation. METHODS: Eighteen male patients aged 37-80 years, undergoing preoperative insertion of an intra-aortic balloon pump (IABP) and elective coronary artery bypass grafting. A thin 1.3FG thermistor was introduced through the pressure lumen to the tip of an 8FG IABP catheter, and the pump rate was set at 1:1. After arrival in the intensive care unit cardiac output (CO) was measured under haemodynamic steady-state conditions hourly for 8-11 h, and arterial bolus thermodilution (BCO(iabp)) and pulmonary artery bolus thermodilution (BCO(pulm)) were determined after the patients' admission to the intensive care unit. RESULTS: A total of 198 data pairs were obtained: 177 with aortic counterpulsation and 21 without. During aortic counterpulsation, median CO was 6.8 l/min for BCO(iabp) and 6.1 l/min for BCO(pulm), without aortic counterpulsation; corresponding values were 7.1 l/min for BCO(iabp) and 6.5 l/min for BCO(pulm) with aortic counterpulsation. Mean bias was +0.77 l/min, limits of agreement ( +/- 2 SD) were -1.27/+2.81 l/min, and mean error (2 SD/[(BCO(iabp )+ BCO(pulm))/2] was 31.4%. Without aortic counterpulsation, corresponding values were +0.43 l/min, -1.03/+1.87 l/min, and 22.4%. CONCLUSIONS: Agreement between BCO(iabp) and BCO(pulm) was satisfactory for CO values between 2.0 and 10 l/min only without aortic counterpulsation. BCO(iabp) CO measurements during aortic counterpulsation after coronary artery bypass grafting cannot be recommended at the present time.

Cerebral near-infrared spectroscopy in adult patients after cardiac surgery is not useful for monitoring absolute values but may reflect trends in venous oxygenation under clinical conditions.

OBJECTIVE: Cerebral near-infrared spectroscopy (NIRS) was evaluated for use in monitoring global oxygenation in adult patients after cardiac surgery. DESIGN: Prospective, randomized clinical monitoring study. SETTING: Intensive care unit for cardiac surgery; university hospital. PARTICIPANTS: The study included 35 patients scheduled for cardiac surgery with insertion of a pulmonary artery catheter; patients with known cerebral-vascular perfusion disturbances were excluded. INTERVENTIONS: Noninvasive cerebral NIRS oxygen saturation (rSO(2)) and conventional intensive care monitoring parameters were assessed. MEASUREMENTS AND MAIN RESULTS: Simple regression analysis was used to assess the correlation of rSO(2) to hemodynamic parameters. There was fair-to-moderate intersubject correlation to hemoglobin concentration (r = 0.45, p < 0.0001) and mixed venous oxygen saturation (SmvO(2)) (r = 0.33, p < 0.0001). Sensitivity and specificity of rSO(2) to detect substantial (>or=1 standard deviation) changes in mixed venous oxygen saturation were 94% and 81%, respectively. CONCLUSIONS: Cerebral NIRS in adult patients might not be the tool to replace mixed venous oxygen monitoring. Further work has to be done to assess its potential to reflect intraindividual trends.

Clinical validation of a digital transcutaneous PCO2/SpO2 ear sensor in adult patients after cardiac surgery.

OBJECTIVE: The aim of this study was to validate the V-Sign digital sensor (SenTec AG, Therweil, Switzerland) for combined noninvasive assessment of pulse oxymetric oxygen saturation (SpO(2)) and transcutaneous carbon dioxide tension (PtcCO(2)) in adults after cardiac surgery. METHODS: In twenty one patients, aged 51-86 years, simultaneous measurements of blood gases with the V-Sign Sensor and with two Nellcor Durasensors (model DS-100A), one at the opposite earlobe and one with a finger clip, were compared first during hyper-, normo- and hypocapnia and at different pulse rates using a pacemaker, and then at 2-h intervals up to 8 h. Agreement was assessed by Bland-Altman analysis. RESULTS: PtcCO(2) data of three patients were excluded because of calibration failure of the device. Median (range) PtcCO(2) for the remaining patients was 5.49 (3.3-7.6) kPa and arterial carbon dioxide tension (PaCO(2)) was 5.43 (3.61-7.41) kPa. Corresponding mean bias was +0.05 kPa and limits of agreement (LOA) were -1.2/+1.3 kPa. During normo- and hypoventilation, mean bias was good at +0.02 and +0.04 kPa respectively, but limits of agreement were poor at -0.67/+0.69 and -0.81/+0.88 kPa. In 10 patients, an initial overshoot of PtcCO(2 )was observed. Mean bias of SpO(2) and pulse rate was close to zero (-1.5% and +0.001 bpm respectively), but limits of agreement were unacceptably high (-21.4/+18.4% and -22.3/+22.3 bpm). CONCLUSIONS: In the present state of development the SenTeC Digital monitor V-Sign device has serious limitations. Additional efforts are necessary to eliminate calibration failures and the initial overshoot of PtcCO(2) as well as to improve detection of SpO(2) and pulse rate.

Cost-effectiveness of routine intraoperative transesophageal echocardiography in pediatric cardiac surgery: a 10-year experience.

The beneficial effect of transesophageal echocardiography (TEE) on medical and surgical treatment of children with congenital heart disease has been established. Its cost-effectiveness, however, has not been extensively studied. We analyzed reports of 580 routine TEE examinations performed in our institution between January 1994 and December 2003 in patients younger than 17 yr who required congenital cardiac surgery. After excluding patients who died immediately postoperatively, we identified 33 patients (5.7%) who required a second bypass run on clear-cut indication, i.e., surgical reoperation, and who clearly benefited from TEE findings. An estimate of both fixed and variable costs revealed a savings of 850 to 2655 Swiss francs (CHF) ($690 to $2130 US) per child. This figure undoubtedly underestimates the true cost-effectiveness of routine intraoperative TEE in this setting because we used mostly conservative estimates of the benefits and liberal estimates of the costs. The potential benefits of TEE in hemodynamic monitoring and medical management, in reduction of postoperative morbidity, and in improvement in the quality of life are intangible and were not considered. Although benefits and costs vary according to market conditions, patient populations, surgical practice, and technical expertise with TEE, our analysis demonstrates substantial cost-effectiveness in the use of routine TEE during pediatric cardiac surgery.