A comparison of three methods that assess tracheal tube leakage: leak conductance, fractional volume loss, and audible assessment.

BACKGROUND: When intubating a child's trachea with an uncuffed tracheal tube (TT), it is current practice in anesthesia and intensive care to use the leak test to assess TT fit. The aim of this study is to compare three measures of assessing leak around uncuffed tracheal tubes in the PICU. METHODS: We obtained institutional ethical permission and written informed consent, prior to any clinical investigation, from the parents of 135 children who had surgery for cardiac defects. On admission to the PICU, we measured leak by audible assessment, fractional volume loss, and leak conductance for each patient. Measurements of fractional volume loss and leak conductance were repeated every 4 h thereafter until extubation. RESULTS: On admission to the PICU, calculated values of leak conductance were significantly different between each grade of audible leak (P < 0.001). Values of fractional volume loss were not significantly different between 'no leak' and 'small leak' grades of leak. Throughout the PICU stay, a significant correlation between mean leak conductance and mean fractional volume loss was found (0.86, 95% CI, 0.81-0.90). Significant agreement within time series of leak conductance and fractional volume recorded for each patient occurred in 47/128 cases (37%). CONCLUSIONS: On admission to the PICU, values of leak conductance are more strongly associated with audible assessment than with fractional volume loss. Throughout PICU stay, leak conductance is associated with fractional volume loss. This study demonstrates that leak conductance, calculated from routinely available pressure and flow signals, has the potential to represent the characteristics of the leak interface between a TT and the trachea.

Mortality in infants with cardiovascular malformations.

UNLABELLED: Cardiovascular malformations are an important cause of infant death and the major cause of death due to malformation. Our aims were to analyse and categorise all deaths in infants with cardiovascular malformations, and to analyse trends in mortality over time and influences on mortality. We obtained details of infant deaths and cardiovascular malformations from the population of one health region for 1987-2006. We categorised deaths by cause and by presence of additional chromosomal or genetic abnormalities or non-cardiac malformations. In 676,927 live births the total infant mortality was 4,402 (6.5 per 1,000). A total of 4,437 infants had cardiovascular malformations (6.6 per 1000) of whom 458 (10.3%) died before 1 year of age. Of this number, 151 (33%) deaths had non-cardiac causes, 128 (28%) were cardiac without surgery and 179 (39%) occurred from cardiac causes after surgery. Death was unrelated to the cardiovascular malformation in 57% of infants with an additional chromosomal or genetic abnormality, in 76% of infants with a major non-cardiac malformation and in 16% of infants with an isolated cardiovascular malformation. Terminations of pregnancies affected by cardiovascular malformations increased from 20 per 100,000 registered births in the first 5 years to 78 per 100,000 in the last 5 years. A total of 2,067 infants (47%) underwent surgery and of these 216 (10%) died before 1 year of age. CONCLUSIONS: A total of 10.4% of infants who died had a cardiovascular malformation and two-thirds of deaths were due to the malformation or its treatment. Mortality declined due to increasing termination of pregnancy and improved survival after operation.

General anesthesia for children with severe heart failure.

Severe heart failure in children is uncommon. The anesthetic management of children with this condition is challenging. The authors aimed to identify the frequency with which anesthesia for short noncardiac surgical procedures or investigations was complicated by life-threatening hemodynamic instability and to describe the anesthetic techniques used. This study retrospectively reviewed the anesthetic charts and notes of children admitted acutely with a diagnosis of severe heart failure (fractional shortening of 15% or less) who received general anesthesia for noncardiac surgical or diagnostic interventions during the 3-year period from September 2005 to September 2008. In this study, 21 children received a total of 28 general anesthetics. Two patients (10%) experienced a cardiac arrest, and both required unplanned admission to the authors' pediatric intensive care unit (PICU) postoperatively. A variety of anesthetic techniques was used. In 27 (96%) of the 28 cases, perioperative inotropic support was required. General anesthesia for children with severe heart failure is associated with a significant complication rate and should be administered by anesthetists familiar with managing all aspects of circulatory support for children in an appropriate setting.

Mechanical versus medical bridge to transplantation in children. What is the best timing for mechanical bridge?

OBJECTIVE: Precise timing of mechanical circulatory support as a bridge to transplantation is crucial for successful outcome. In our practice, increasing metabolic injury resulting from third organ (renal/gut) dysfunction is an indication for mechanical circulatory support. It is not known how metabolic injury would influence the outcomes in these patients. In this study we compared biochemical and clinical parameters between children who received mechanical circulatory support and those who were treated with medical management alone as a bridge to transplantation. METHODS: Data from 24 patients were retrospectively analysed from their records. There were 11 patients in the mechanical group. In this group, five patients received biventricular assist device, five received veno arterial extra corporeal membrane oxygenation and one received left ventricular assist device. In the medical group, there were 13 patients who received various levels of inotropic support before transplantation. Five clinical and three biochemical parameters were identified and compared between the mechanical and medical groups. Mortality prior to transplantation was also compared between the two groups. Transplantation was the end point of the study. RESULTS: Serum creatinine and serum lactate levels were significantly higher in the mechanical group (P=0.006 and 0.001, respectively), reflecting advanced metabolic injury in these patients. Mean fractional shortening in the mechanical group was 8.4%, compared to 14.5% in the medical group which was statistically significant (P=0.02). All of the 11 patients in the mechanical group were ventilated compared to 7 of the 13 (53.8%) in the medical group. Need for renal support was higher in the mechanical group (83.3%) in comparison to none in the medical group (P=0.023). Mortality in both groups was comparable with two patients in each group. 11 patients in the medical group (84.6%) and 9 in the mechanical group (81.8%) reached transplantation. CONCLUSION: This study confirmed that patients in the mechanical group were considerably worse in metabolic terms when compared to the medical group. Final outcome of bridging them to transplantation was comparable. This study seem to support the justification of reserving the mechanical circulatory support to those who are metabolically more injured without adversely affecting their outcomes.

Long-term outcome following extracorporeal membrane oxygenation for congenital diaphragmatic hernia: the UK experience.

OBJECTIVE: We evaluated the long-term outcome of neonates receiving extracorporeal membrane oxygenation (ECMO) for congenital diaphragmatic hernia (CDH). Study design A retrospective review of all 73 neonates with CDH supported with ECMO in the United Kingdom between 1991 and 2000, with follow-up to January 2003. Information was from hospital charts and from communication with family doctors and pediatricians. Median follow-up period for survivors was 67 months. RESULTS: 46 infants (63%) were weaned from ECMO, 42 (58%) survived to hospital discharge, and 27 (37%) survived to age 1 year or more. A higher birth weight, higher 5-minute Apgar score, and postnatal diagnosis were "pre-ECMO" predictors of long-term survival. Comorbidity was common in long-term survivors: 13 (48%) had respiratory symptoms, 16(59%) had gastrointestinal problems, and 6 (19%) had severe neurodevelopmental problems. Only 7 children were free of significant neurodevelopmental deficit and required no further medical or surgical intervention. CONCLUSION: Using the current referral criteria, ECMO can be used to support the sickest neonates with CDH. However, there is significant mortality in the first year of life, and long-term physical and neurodevelopmental morbidity remains in the majority of survivors.