Diagnosis of postoperative arrhythmias following paediatric cardiac surgery.

Arrhythmias are commonly encountered in the paediatric intensive care unit setting, most frequently in the setting of postoperative congenital heart disease. Postoperative arrhythmias are an important cause of morbidity in children in the postoperative period following cardiac surgery for congenital cardiac lesions. It is important for all paediatric critical care physicians involved in the care of these children to understand the potential mechanisms involved and how to make an accurate diagnosis. The existing literature has focused on small groups and specific arrhythmias. There is a paucity of literature to guide the clinician in approaching arrhythmias in the paediatric intensive care unit setting. Our objective was to review the recognition and diagnosis of paediatric arrhythmias in the postoperative period following congenital cardiac surgery. Timely and accurate identification of the rhythm disturbance is mandatory and allows for the institution of effective, rhythm specific management strategies.

Abdominal compartment syndrome complicating paediatric extracorporeal life support: diagnostic and therapeutic challenges.

We report three paediatric cases, and summarise the reported experience in two others, with cardiorespiratory failure requiring extracorporeal life support for which supportive pump flows could not be maintained due to abdominal compartment syndrome. In two of our patients, the mechanism of abdominal compartment syndrome was massive intra-abdominal fluid extravasation secondary to sepsis, while in the third, the mechanism was post-traumatic intra-abdominal haemorrhage. Although all three children eventually died, decompressive laparotomy and arrest of haemorrhage in the trauma patient restored venous return and enabled technically adequate extracorporeal life support. In two previously reported cases of sepsis with massive fluid resuscitation resulting in abdominal compartment syndrome, one patient died without attempted decompression, while the other patient survived after peritoneal catheter placement restored venous return. Once correctable causes of inadequate venous cannula drainage have been excluded, abdominal compartment syndrome should be considered in any patient on extracorporeal life support with a taut abdomen and reduced venous return. If abdominal compartment syndrome can be proven or is strongly suspected, there may be a role for selective decompressive laparotomy.

Correlation of transcutaneous hepatic near-infrared spectroscopy readings with liver surface readings and perfusion parameters in a piglet endotoxemic shock model.

PURPOSE: To determine whether transcutaneous liver near-infrared spectrophotometry (NIRS) measurements correlate with NIRS measurements taken directly from the liver surface, and invasive blood flow measurements. PROCEDURE: Laparotomy was performed in 12 Yorkshire piglets, and ultrasound blood flow probes were placed on the hepatic artery and portal vein. Intravascular catheters were inserted into the hepatic and portal veins for intermittent blood sampling, and a pulmonary artery catheter was inserted via the jugular vein for cardiac output measurements. NIRS optodes were placed on skin overlying the liver and directly across the right hepatic lobe. Endotoxemic shock was induced by continuous infusion of Escherichia coli lipopolysaccharide O55:B5. Pearson's correlations were calculated between the NIRS readings and the perfusion parameters. FINDINGS: After endotoxemic shock induction, liver blood flow, and oxygen delivery decreased significantly. There were statistically significant correlations between the transcutaneous and liver-surface NIRS readings for oxyhemoglobin, deoxyhemoglobin, and cytochrome c oxidase concentrations. There were similar significant correlations of the transcutaneous oxyhemoglobin with both the mixed venous and hepatic vein saturation, and mixed venous and hepatic vein lactate. CONCLUSIONS: Transcutaneous NIRS readings of the liver, in an endotoxemic shock model, correlate with NIRS readings taking directly from the liver surface, as well as with global and specific organ-perfusion parameters.

Acute renal failure in children undergoing cardiopulmonary bypass.

OBJECTIVE: To investigate the incidence, implicating factors and outcome of acute renal failure after cardiopulmonary bypass in patients admitted to a paediatric intensive care unit. DESIGN: Prospective observational pilot study. SETTING: A 14 bed paediatric intensive care unit in a university affiliated, tertiary care referral children's hospital. PATIENTS: One hundred and one children (less than sixteen years of age) admitted to the Pediatric Intensive Care Unit following cardiopulmonary bypass between June 2003 and May 2004. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: PRISM-III score was calculated on admission. Baseline admission urea (mmol/L) and creatinine (micromol/L) serum levels and highest urea and creatinine levels were measured. Urine output (mL/kg/hour) and frusemide dose (mg/kg/day) were also noted. A baseline inotrope score was calculated on admission and the highest inotrope score was noted based on maximum infused doses of inotrope in the first 36 hours. The surgical procedure was used to determine a Jenkins score. Eleven (11%) children developed acute renal injury (doubling of creatinine), one child (1%) developed acute renal failure (tripling of creatinine) and one child died (1%). No child required dialysis for acute renal failure and none developed chronic renal impairment. Low cardiac output was the only significant risk factor identified for developing acute renal injury or failure. CONCLUSIONS: Acute renal injury is common and occurred in 11% of our children following congenital cardiac surgery, but acute renal failure requiring dialysis is uncommon.