Jens Pedersen

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).

Tissue Injury and the Inflammatory Response to Pediatric Cardiac Surgery with Cardiopulmonary Bypass: A Descriptive Study

Background There are few detailed descriptions of the inflammatory response to cardiac surgery with cardiopulmonary bypass (CPB) in children beyond 24 h postoperatively. This is especially true for the antiinflammatory cytokines and the extent of tissue injury. The aim of the current study was to describe the inflammatory and injury responses in uncomplicated pediatric cardiac surgery with CPB, where methylprednisolone and modified ultrafiltration (MUF) were used. Methods Blood samples were collected up to 48 h postoperatively. Cytokines (tumor necrosis factor-&agr; and interleukin-6, -1&bgr;, -10, and -1ra), complement (C3d and C4d) and coagulation system (prothrombin activation fragments 1 and 2 and antithrombin III) activation, neutrophil elastase, and the resulting tissue injury (creatine kinase, lactate dehydrogenase, alanine transaminase, amylase, and &ggr;-glutamyl transferase) were measured. Results The proinflammatory cytokine release varied widely, in contrast to a clear-cut antiinflammatory response. Cytokine concentrations did not decrease immediately after MUF, and no rebound increases later in the postoperative period were observed. The coagulation system, but not complement, was activated. There was a late release of C-reactive protein. Tissue injury could be quantified biochemically without evidence of hepatic or pancreatic dysfunction. Conclusion In this group of uncomplicated subjects, the antiinflammatory cytokine and tissue injury responses were well defined, in contrast to a variable proinflammatory cytokine release. This was accompanied by activation of the coagulation system but not of complement. Concentrations of inflammatory mediators did not decrease immediately after MUF, and there was no evidence for rebound release later in the postoperative period.

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.

Effect of modified ultrafiltration on the inflammatory response in paediatric open-heart surgery: a prospective, randomized study

Modified ultrafiltration (MUF) is often used in conjunction with paediatric cardiac surgery with cardiopulmonary bypass (CPB) and is thought to improve clinical outcome. It is unclear whether these improvements (if any) are due to the removal of inflammatory mediators. In this prospective study, 18 children aged 12-24 months undergoing uncomplicated cardiac surgery with methylprednisolone added in the pump prime were randomized to receive CPB with ( n = 10) and without ( n = 8) MUF. Cytokines (TNFα, IL-6, IL- 1β, IL-10, IL-1ra), complement split products (C3d, C4d) and coagulation system activation (F1+ 2, ATIII) were measured pre-, peri- and up to 48 h postoperatively. For clinical outcome, the alveolar-arterial oxygen (A-a) gradient, transfusion requirement, drain loss, mean blood pressure and requirement for inotropic support were registered up to 24 h postoperatively. Our results show an improvement in postoperative oxygenation as well as a tendency towards decreased drain loss and improved haemodynamics in the MUF group. There were no intergroup differences detectable for TNFα, IL-1β, IL-1ra, complement and coagulation markers. We conclude that MUF in itself does not significantly influence TNFα, IL-1β, IL-1ra and the complement and coagulation profiles in children undergoing cardiac surgerywith CPB. Despite this, there was some evidence for improved clinical outcome. Our results do not support that MUF improves postoperative organ function by modulation of the measured markers of inflammation.

Pediatric multiplane transesophageal echocardiography in congenital heart disease: New possibilities with a miniaturized probe

In recent years, transducers for multiplane Doppler echocardiography have demonstrated their superior imaging performance in adult patients. To date, the size of these probes has limited their use in pediatric patients. In this article, we report our initial experience with a recently developed miniaturized transducer with all conventional imaging and Doppler modalities. The study focused primarily on imaging performance by comparing standard biplane images with those obtained in oblique planes. The investigations were carried out intraoperatively or during interventional catheterization in patients with congenital heart disease. We observed no complications in a study population of 15 children (weight range of 5 to 63 kg and an age range of 96 days to 11 years). The probe was easy to handle and provided excellent images. Additional information was obtained in several cases and documentation of clinical findings was easier because an optimal image plane almost always could be displayed. We concluded that pediatric multiplane Doppler echocardiography has considerably improved investigative performance compared with the conventional monoplane or biplane studies normally available for this age group. In neonates, however, investigation with the multiplane technique is limited by the size of the patient.

Transoesophageal echocardiographic monitoring during paediatric cardiac surgery: obtainable information and feasibility in 532 children

Background: We hypothesized that transoesophageal echocardiography (TOE) performed by the anaesthesiologists would be beneficial for monitoring purposes during paediatric cardiac surgery. We present the results for the first 5 years in 532 consecutive children.

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.

Survival and morbidity following congenital heart surgery in a population-based cohort of children--up to 12 years of follow-up.

OBJECTIVES The Risk Adjusted Classification for Congenital Heart Surgery can predict early mortality. However, the relation to long-term outcome in terms of mortality and morbidity is unknown. DESIGN We did a population-based follow-up study of 801 children undergoing congenital heart surgery between 1996 and 2002. All patients were followed from surgery until death or January 1, 2008. Operations were classified according to the Risk Adjusted Classification for Congenital Heart Surgery. Each patient was matched by age and sex with 10 population controls. Cox regression analysis, area under the receiver operator curve and competing risk analysis were used for the analyses. RESULTS Overall follow-up was 99.6%. The distribution of the Risk Adjusted Classification for Congenital Heart Surgery was: Category one 20%, category two 37%, category three 27%, category four 8%, category five 0% and category six 2%. Overall survival after a median follow-up of 8.2 years was 86% (95% confidence interval: 83-88%), with 54 early deaths occurring within 30 days after surgery and 57 late deaths. Long-term survival in those who were alive 30 days after surgery was 92% (90-94%); ranging from 98% (93-100%) in risk category one to 33% (5-68%) in category six. Survival overall and beyond 30 days was lower in each risk category than in controls (P < .001). During follow-up, 124 (15%) patients had new operations and 106 (13%) catheter-based interventions. These events were more frequent in category three, four, and six compared with category one, with no difference between category one and two. The area under the receiver operator curve for long-term mortality was 0.81 (95% confidence interval 0.75-0.87). CONCLUSIONS Children operated for congenital heart disease have impaired survival and often undergo new operations or catheter-based interventions. The risk of these events is related to the surgical complexity according to the Risk Adjusted Classification for Congenital Heart Surgery.

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.