Lactate levels predict mortality and need for peritoneal dialysis in children undergoing congenital heart surgery.

BACKGROUND: The purpose of this study was to investigate whether an initial post-operative lactate level is a predictor of mortality, need for peritoneal dialysis (PD), duration of intubation or length of stay (LOS) in the intensive care unit (ICU) in children undergoing cardiac surgery. METHOD: A retrospective, observational follow-up study was conducted in 206 children undergoing cardiac surgery from 2006 to 2007. Multivariate logistics regression analyses were performed to determine whether the lactate level was an independent risk factor. The lactate concentration at arrival in the ICU, outcome and risk factors (patient demographics, surgical complexity, duration of cardiopulmonary bypass and inotropic score) were obtained from the electronic patient data management program and medical records. RESULT: The median (interquartile range) lactate level was 1.9 mmol/l (1.3-2.7) in children immediately after cardiac surgery and a mortality of 3.9%. Eight percent of the children had a lactate level higher than 4.5 mmol/l. An increased lactate level ≥4.5 mmol/l resulted in an odds ratio (95% confidence intervals) of 8.4 (1.5-46.1) for mortality and an odds ratio of 16.9 (2.7-106.8) for PD after adjusting for Risk Adjustment for Congenital Heart Surgery 1. Because of the low number of deaths, limited confounder analysis was performed. Duration of intubation and LOS in the ICU were not associated with the initial lactate level when adjusting for confounders. CONCLUSION: The initial post-operative lactate level was a predictor of mortality and need for PD in children undergoing surgery for congenital heart disease.

Clinical outcome in children with acute renal failure treated with peritoneal dialysis after surgery for congenital heart disease.

The present single-center cohort study was based on a clinical intensive care unit database containing data on 1128 consecutive children undergoing their first operation for congenital heart disease between 1993 and 2002 at Aarhus University Hospital, Skejby, Denmark. A total of 130 (11.5%) children developed postoperative acute renal failure (ARF) managed with peritoneal dialysis (PD). Logistic regression analysis was used to examine risk factors for complications related to PD and to compare mortality between ARF and non-ARF patients controlling for potential confounding factors. A total of 43 complications related to PD were registered in 27 (20.8%) patients. Major complications were seen in eight (6.2%) patients, and only two (1.5%) patients were switched to hemodialysis after peritonitis and hemicolectomy due to bowel perforation. The main risk factors for complications to PD were duration of PD, high RACHS-1 score (Risk Adjusted Classification for Congenital Heart Surgery), and hyperkalemia at initiation of PD. Overall, in-hospital mortality was 6.8% (76/1128). Mortality of ARF patients was 20.0% compared to 5.0% among non-ARF patients (adjusted odds ratio=1.91, 95% confidence interval=1.10-3.36). After stratification, ARF was strongly associated with increased mortality in the subgroups of patients with the lowest overall risk of dying (age> or =1 year, body weight> or =5 kg, RACHS-1 score <3, and no preoperative cyanosis). For patients at high risk of dying (age <1 year, body weight <5 kg, RACHS-1 score> or =3, cardiopulmonary bypass time> or =60 min, and preoperative cyanosis), the association between ARF and mortality was substantially weaker. In conclusion, postoperative ARF was associated with increased mortality in children operated for congenital heart disease. Major complications to PD were few, and our data strongly support that PD is a simple, safe, feasible, and robust dialysis modality for the management of ARF in children.

Risk factors for acute renal failure requiring dialysis after surgery for congenital heart disease in children.

BACKGROUND: Limited data exist on the risk factors for acute renal failure (ARF) following cardiac surgery in children with congenital heart disease. This cohort study was conducted to examine this subject, as well as changes in the incidence of ARF from 1993 to 2002, the in-hospital mortality and the time spent in the intensive care unit (ICU). METHODS: One thousand, one hundred and twenty-eight children, operated on for congenital heart disease between 1993 and 2002, were identified from our prospectively collected ICU database to obtain data on potential risk factors. RESULTS: A total of 130 children (11.5%) developed ARF after surgery. A young age [> or =1.0 vs. <0.1 year; odds ratio (OR), 0.23; 95% confidence interval (CI), 0.12-0.46], high Risk Adjusted Classification of Congenital Heart Surgery (RACHS-1) score (OR, 2.72; 95% CI, 1.66-4.45) and cardiopulmonary bypass (CPB) (<90 min vs. none; OR, 2.68; 95% CI, 1.03-6.96; > or =90 min vs. none; OR, 12.94; 95% CI, 5.46-30.67) were independent risk factors for ARF. The risk of ARF decreased during the study period. Children with ARF spent a significantly longer time in the ICU (2-7 days vs. <2 days, P = 0.002; > or =7 days vs. <2 days, P < 0.001) compared with non-ARF patients, and showed increased in-hospital mortality (20% vs. 5%, P < 0.001). CONCLUSION: A young age, high RACHS-1 score and CPB were independent risk factors for ARF after surgical procedures for congenital heart disease in children. The risk of ARF decreased during the study period. Children with severe ARF spent a longer time in the ICU, and the mortality in ARF patients was higher than that in non-ARF patients.

Convective warming blankets improve peroperative heat preservation in congenital heart surgery.

Peroperative heat preservation, following hypothermic cardiopulmonary bypass (CPB) in children, has always been a challenge to the anaesthetist. We studied the efficiency of a convective heating system on peroperative heat preservation in 50 children undergoing congenital heart surgery. Twenty-five children, rewarmed by CPB and heating mattress, were randomly selected (Group 1). Another 25 children, rewarmed by CPB, heating mattress and convective warming blankets in addition (Group 2), were selected so the two groups were comparable regarding age, weight and anaesthetic management. The central and peripheral temperatures were measured during bypass, at the end of bypass and at the end of operation. A retrospective evaluation showed that during bypass the peripheral temperature was significantly lower in Group 2 than in Group 1, with no significant difference in central temperature. At the end of bypass there was no significant difference between the two groups. At the end of operation the central and peripheral temperatures were significantly higher in Group 2. In conclusion convective warming blankets are effective in keeping or even raising the temperature following congenital heart surgery.

Modified ultrafiltration in paediatric cardiac surgery.

The effect of modified ultrafiltration (MUF) after cardiopulmonary bypass for paediatric cardiac surgery was evaluated in 138 children with moderate to severe congenital heart disease. The median age was 0.4 years (0 days to 6.5 years), and the weight 5.3 kg (2.2-20 kg). The operation was discontinued in six cases, three because of technical problems and three because of unstable circulation. One-hundred-and-thirty-four patients were ultrafiltrated for a median of 12 min (2-27 min) with an ultrafiltrate of median 44 ml/kg (6-118 ml/kg). Haematocrit was significantly increased from 28% (20-39%) to 36% (26-51%) and systolic arterial pressure from 56 mmHg (30-85 mmHg) to 74.0 mmHg (32-118 mmHg). Furthermore arterial oxygenation was significantly increased from 30.8 kPa (4.8-70.4 kPa) to 34.1 kPa (4.9-80.6 kPa), and arterial carbon dioxide tension from 4.8 kPa (3.1-7.3 kPa) to 5.1 kPa (3.1-7.6 kPa). Heart rate was significantly reduced from 145 beats/min (92-201 beats/min) to 136 beats/min (88-200 beats/min). There were no significant differences in central venous pressure, left atrial pressure and base excess before and after MUF. MUF increases systolic blood pressure, haematocrit, arterial oxygen and carbon dioxide tension coming off bypass in paediatric cardiac surgery and reduces heart rate and postoperative fluid overload.

Perioperative metoprolol reduces the frequency of atrial fibrillation after thoracotomy for lung resection.

OBJECTIVE: The association of atrial fibrillation with thoracic surgical procedures is well known, but nevertheless its cause is not well defined. Increased sympathetic activity may play a role in the development of atrial fibrillation, and reduced beta-receptor activity may be advantageous. The objective was to evaluate the effect of oral beta-blockade on the frequency of atrial fibrillation and to evaluate some possible causative factors. DESIGN AND SETTING: The study was prospective, randomized, and double-blind, and was conducted at Aarhus University Hospital. PARTICIPANTS: Thirty patients without previous or present cardiovascular history undergoing elective thoracotomy for lung resection. INTERVENTIONS: The patients received either 100 mg of metoprolol or placebo orally before surgery and once daily postoperatively. Anesthesia consisted of a thoracic epidural block combined with general intravenous anesthesia. Epidural morphine was continued postoperatively. MEASUREMENTS AND MAIN RESULTS: Patients were monitored with electrocardiograms (ECGs), capillary pulse oximetry, invasive hemodynamic monitoring, central venous oxygen saturation, arterial blood gases, serum electrolytes, and fluid balances. Atrial fibrillation developed in 23.3% of the patients, 6.7% after metoprolol compared with 40% in the placebo group. Atrial fibrillation developed a mean of 2.9 days postoperatively. The predominant hemodynamic findings were perioperative lower oxygen consumption and postoperative lower cardiac index after metoprolol. Patients developing atrial fibrillation had much higher oxygen consumption and postoperative cardiac index than other patients. CONCLUSION: Perioperative oral beta-blockade can reduce the frequency of atrial fibrillation without serious side effects. Increased sympathetic activity is one of the predominant factors in the cause of this complication.

Hemodynamic predictors of atrial fibrillation or flutter after coronary artery bypass grafting.

The cumulated incidence of atrial fibrillation or flutter after coronary artery bypass grafting is 30%. The causes of these arrhythmias have not yet been sufficiently identified. We therefore undertook the present study to analyze the possible association of hemodynamic function during the various phases of coronary artery bypass grafting and the later development of atrial fibrillation/flutter. Hemodynamic function was measured with a pulmonary artery catheter in 120 consecutive patients undergoing elective coronary artery bypass surgery. Thirty-five (29%) of the patients developed atrial fibrillation/flutter. Logistic regression analysis identified independent predictors of atrial fibrillation/flutter. After induction of general anesthesia, the relative risk (95% confidence interval) of older age was 1.09/year (1.03-1.16), and the reduction in relative risk by an increase in left ventricular stroke work was 0.96/gm (0.93-0.99). After weaning from the extracorporeal circulation the independent significant predictors were age, relative risk 1.07/year (1.01-1.13), and increased central venous pressure, relative risk 1.12/mm Hg (1.00-1.26). At the time of admission to the intensive care unit, the relative risk of age was 1.10/year (1.03-1.18), and the relative risk of an increased central venous pressure was 1.26/mm Hg (1.06-1.49). However, the best prediction model (prediction after induction of general anesthesia) only provided a median predicted probability of atrial fibrillation/flutter of 0.37 for the patients who had atrial fibrillation/flutter, and a median predicted probability of atrial fibrillation/flutter of 0.20 for the patients without these arrhythmias. We identified possible hemodynamic predictors of atrial fibrillation/flutter after coronary bypass surgery, but the use of a risk stratification for development of atrial fibrillation/flutter based on hemodynamic function cannot be recommended.

Atrial fibrillation and flutter after coronary artery bypass surgery: epidemiology, risk factors and preventive trials.

Atrial fibrillation and atrial flutter are common arrhythmias after coronary artery bypass grafting. Although the consequences of the arrhythmia are generally not life-threatening, it constitutes a major clinical problem often requiring conversion to sinus rhythm. Atrial fibrillation or flutter can result in hypotension, heart failure, pneumonia, and stroke. This article reviews the literature on epidemiology, electrophysiology, risk factors, and preventive trials. The major conclusions are: (1) In patients undergoing coronary artery bypass surgery, the incidence of postoperative atrial fibrillation or flutter is 20-30%, the peak incidence being on the second or third postoperative day. (2) The strongest independent preoperative predictor for atrial fibrillation or flutter is the patients' age. (3) Intra-atrial conduction delay recorded pre and peroperatively may predict development of atrial fibrillation. (4) Peroperative inducibility of atrial fibrillation by pacing the right atrium may identify patients at risk for postoperative atrial fibrillation. (5) Development of postoperative atrial fibrillation or flutter has not been associated with peroperative or postoperative events. (6) The specificity and sensitivity of age and other possible relevant factors for prediction of atrial fibrillation or flutter after coronary artery bypass grafting is low. (7) No effective prophylactic regimen has yet been established.