John Stickley

Changes in the profile of paediatric intensive care associated with centralisation

Abstract.Objectives: To compare intensive care admissions from a defined population of children in 1991 and 1999, during a period of organisational change and centralisation of paediatric intensive care. Design: Two 12-month population-based audits were compared. Data were collected from hospitals in Birmingham and the surrounding districts. Denominator data were obtained from the Office for National Statistics. The place and rate of intensive care admission, the use of mechanical ventilation at admission, mortality and length of stay were compared. Setting: Hospitals in the West Midlands. Participants: All children (<15xa0yrs) living in Birmingham who received intensive care during the study periods. Measurements and results: The number of Birmingham resident children admitted for intensive care increased from 277 to 510 (p<0.0001) i.e. from 1.3 to 2.3 admissions per 1,000 children per year. The proportion of admissions to the principal paediatric intensive care unit increased from 60% to 90% (p<0.0001) in association with its expansion from 6 to 18 beds. Length of ICU stay decreased from 103 to 74xa0h (difference 29xa0h, 95%CI, 4.78–54.2xa0h, p=0.0117). Child mortality fell over this period by 34 deaths per 100,000 children (95%CI 16–51, p<0.0001). The proportion of children requiring mechanical ventilation at admission to intensive care was unchanged. Conclusions: Centralisation by expansion of the lead centre was associated with a large increase in the numbers of children receiving intensive care consistent with an unmet need for paediatric intensive care in 1991, which may still exist. Centralisation of paediatric intensive care may have contributed to the fall in child mortality over this time period.

Lack of agreement between arterial and central venous blood glucose measurement in critically ill children

Dear Sir, We were interested to read the article by Critchell et al. [1] highlighting concerns about the accuracy of bedside capillary blood glucose measurements in critically ill patients. We would agree that the importance of sampling site for blood glucose measurement has been under-emphasized in the published studies on hyperglycaemia and tight glycaemic control. The majority of studies linking hyperglycaemia with adverse clinical outcome have not provided data on the site of sampling. We would like to share preliminary data regarding the use of central venous blood sampling for glucose measurement in critically ill children. The objective of this preliminary study was to compare blood glucose concentrations in simultaneously drawn arterial and central venous blood glucose samples taken for clinical purposes. Paired arterial and central venous blood gas samples were taken to obtain information about oxygen extraction and the results were prospectively documented. Blood glucose was measured on a blood gas analyzer (Bayer Rapidlab; electrochemical biosensor), which is subject to strict quality control by the Clinical Chemistry department. No glucose containing solution was infused into either the arterial or the central venous sampling lines. A total of 245 paired arterial and central venous blood samples were obtained from 71 children, age range 5 days–14 years, between January and October 2006. The majority of cases were children post cardiac surgery, reflecting a group of patients in whom regular assessment of oxygen extraction is undertaken. The median number of samples per patient was 2 (range 1–22). The samples included a wide range of arterial blood glucose values, from 2.4 to 23 mmol/l. There was poor agreement between arterial and central venous blood glucose (Fig. 1). The central venous blood glucose was frequently higher than the arterial blood glucose (median 0.4 mmol/l, CI 0.3–0.5, P 0.001 Wilcoxon Signed Rank test). On occasions, the difference exceeded 5 mmol/l. The implications of these findings for titration of insulin therapy are obvious. Inappropriate adjustments to insulin therapy could be made and, importantly, hypoglycaemia could go undetected if central venous sampling is used to monitor blood glucose in this population of critically ill children. It is common for a child to be managed without an arterial line once their cardio-respiratory condition has stabilized, and for bloods to be taken through a central line, if present, to avoid the need for venepuncture. In contrast with our findings, a recent study by Evron et al. [2] found no difference between arterial and central venous blood glucose concentration in adult patients undergoing major orthopaedic or colon surgery though these patients were all studied in the context of general anaesthesia and surgery and were not critically ill. It is possible that glucose containing fluids infused into a vein peripheral to the central venous line or infused via one of the other central venous line lumens could have contaminated the central venous sample that was taken. As this was an opportunistic study performed under uncontrolled conditions information about glucose infusions was not collected, other than confirmation that no glucose containing fluid was infused into either the arterial or central venous sampling lines. However, alternative explanations are possible in that glucose may be generated in peripheral tissues, most notably in muscle, during critical illness and released into the venous system [3, 4]. 0 5 10 15 20 25

Rapid Ventricular Pacing for Catheter Interventions in Congenital Aortic Stenosis and Coarctation: Effectiveness, Safety, and Rate Titration for Optimal Results

INTRODUCTIONnInfants and children with congenital aortic stenosis and coarctation of the aorta can be treated by catheter intervention. There are several pharmacological and mechanical techniques described to overcome the balloon movement; none, however, have proved entirely satisfactory. An alternative method to achieve balloon stability is the use of rapid ventricular pacing. We describe our experience with titrating the pacing rate and the use of this technique.nnnMETHODSnA retrospective review of database was performed, to identify patients who underwent transcatheter intervention with rapid ventricular pacing. Invasive systemic pressures were documented with a catheter in the aorta. Rapid ventricular pacing was initiated at the rate of 180 per minute and increased by increments of 20 per minute to a rate required to achieve a drop in systemic pressure by 50% and a drop in pulse pressure by 25%. The balloon was inflated only after the desired pacing rate was reached. Pacing was continued until the balloon was completely deflated.nnnRESULTSnThirty patients were identified, 29 of whom had interventions with rapid ventricular pacing. Balloon valvuloplasty of aortic valve was performed on 25 patients while 4 patients had stenting for coarctation by this technique. The rate of ventricular pacing required ranged from 200 to 260 per minute with a median rate of 240. Balloon stability at the time of intervention was achieved in 27 patients.nnnCONCLUSIONnRapid ventricular pacing is a safe and effective method to provide transient decrease in cardiac output at the time of transcatheter interventions to achieve balloon stability.

The relationship between blood lactate concentration, the Paediatric Index of Mortality 2 (PIM2) and mortality in paediatric intensive care.

IntroductionBlood lactate concentration predicts mortality in neonates, infants, children and adults, with evidence that it has better predictive power than other markers of acid–base status such as absolute base excess or pH.ObjectiveTo investigate whether blood lactate concentration on admission predicts mortality in paediatric intensive care and if its addition can improve the performance of the Paediatric Index of Mortalityxa02 (PIM2) mortality prediction score.Design and settingRetrospective cohort study in one 20-bed UK paediatric intensive care unit (PICU) using data from the PICU clinical and blood gas analyser databases between 2006 and 2010. Only cases with a blood lactate concentration measured at the same time as the PIM2 variables were included. Logistic regression was used to assess if blood lactate concentration predicted mortality independently of PIM2, adjusting for potential confounders, and if it could replace absolute base excess in the PIM2 model.ResultsThere were 155 deaths amongst 2,380 admissions (6.5xa0%). Admission lactate in non-survivors was higher than in survivors (mean [standard deviation, SD]) 6.6 [5.6] versus 3.0 [2.5]xa0mmol/l, had a positive association with mortality [adjusted odds ratio (OR) for death per unit (mmol/l)] increase 1.11 [95xa0% confidence interval (CI) 1.06–1.16; pxa0<xa00.001] and significantly improved the model fit of PIM2 when it replaced absolute base excess (pxa0<xa00.001).ConclusionsPICU admission blood lactate concentration predicts mortality independently of PIM2. Given the limitations of this study, a prospective multi-centre evaluation is required to establish whether it should be added to the PIM2 model with or without replacement of base excess.

Catheter interventions in the staged management of hypoplastic left heart syndrome

AIMnTo analyse the current practice and contribution of catheter interventions in the staged management of patients with hypoplastic left heart syndrome.nnnMETHODSnThis study is a retrospective case note review of 527 patients undergoing staged Norwood/Fontan palliation at a single centre between 1993 and 2010. Indications and type of catheter interventions were reviewed over a median follow-up period of 7.5 years.nnnRESULTSnA staged Norwood/Fontan palliation for hypoplastic left heart syndrome was performed in 527 patients. The 30-day survival rate after individual stages was 76.5% at Stage I, 96.3% at Stage II, and 99.4% at Stage III. A total of 348 interventions were performed in 189 out of 527 patients. Freedom from catheter intervention in survivors was 58.2% before Stage II and 46.7% before Stage III. Kaplan-Meier freedom from intervention post Fontan completion was 55% at 10.8 years of follow-up. Post-stage I interventions were mostly directed to relieve aortic arch obstruction--84 balloon angioplasties--and augment pulmonary blood flow--15 right ventricle-to-pulmonary conduit interventions; post-Stage II interventions centred on augmenting size of the left pulmonary artery--73 procedures and abolishing systemic venous collaterals--32 procedures. After Stage III, the focus was on manipulating the size of the fenestration--42 interventions--and the left pulmonary artery -31 procedures.nnnCONCLUSIONnInterventional cardiac catheterisation constitutes an integral part in the staged palliative management of patients with hypoplastic left heart syndrome. Over one-third (37%) of patients undergoing staged palliation required catheter intervention over the follow-up period.

Early change in blood glucose concentration is an indicator of mortality in critically ill children

ObjectiveHyperglycaemia is associated with increased mortality in critically ill patients. A number of studies have highlighted an association between increased variability of blood glucose (BG) concentration and mortality, supporting a survival disadvantage if BG homeostasis is lost. By exploring the longitudinal BG profile of individual children over time, this study investigates the importance of intact homeostasis early after admission to the paediatric intensive care unit (PICU).Design, setting, and patientsRetrospective single-centre observational study in a large multi-specialty PICU in the UK. Children admitted between August 2003 and February 2006 were included unless they met exclusion criteria. Data were merged from the PICU clinical database and blood gas analyser database by means of a unique PICU identifier. BG was measured frequently on a blood gas analyser (Bayer Rapidlink). Primary outcome was 100-day mortality. BG parameters were investigated for possible associations with mortality.Measurements and main resultsA total of 1,763 patients were included (median age 1.1xa0years; IQR 0.1–5.8). Although admission BG was not associated with mortality, a survival advantage was found in children who showed a reduction in BG on day 1 relative to the admission BG value (pxa0<xa00.001). This remained statistically significant (pxa0=xa00.007) after adjusting for severity of illness.ConclusionsThis study supports an association between early BG profile and mortality in children admitted to PICU, with increased survival in those who demonstrate a fall in BG on day 1 relative to PICU admission. These findings are consistent with a survival advantage of intact BG homeostasis.

Right ventricular outflow tract stent versus BT shunt palliation in Tetralogy of Fallot

Objective This study sets out to compare morbidity, mortality and reintervention rates after stenting of the right ventricular outflow tract (RVOT) versus modified Blalock-Taussig shunt (mBTS) for palliation in patients with tetralogy of Fallot (ToF)-type lesions. Methods Retrospective case review study evaluating 101 patients (64 males) with ToF lesions who underwent palliation with either mBTS (n=41) or RVOT stent (n=60) to augment pulmonary blood flow over a 10-year period. Procedure-related morbidity, mortality and reintervention rates were assessed and compared. Results Admission rate to paediatric intensive care unit (PICU) was lower in the RVOT stent group (22% vs 100%; p<0.001). Thirty-day mortality in the RVOT stent group was (1/60 (1.7%)) compared with (2/41 (4.9%)) in the mBTS group (p=0.565). Mortality until surgical repair was comparable in both groups (5/60, 8.4%, including three non-cardiac death in the RVOT stent group vs 2/41, 4.9% (p=0.698)). Total hospital length of stay was shorter for the RVOT stent group (median 7 days vs 14 days; p<0.003). Time to surgical repair was shorter in the RVOT stent group (median 232 days, IQR 113–360) compared with the mBTS group (median 428 days, IQR 370–529; p<0.001) due to improved pulmonary arterial growth. Conclusion RVOT stenting in Fallot-type lesions can be accomplished safely, with lower PICU admission rate, a shorter hospital length of stay and shorter duration of palliation until complete repair compared with mBTS palliation.

Mentoring new surgeons: can we avoid the learning curve?

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Transcatheter Retrieval of Cardiovascular Foreign Bodies in Children: A 15-Year Single Centre Experience

There has been a rapid increase in the practice of interventional catheter treatment of congenital heart disease. Catheter retrieval of embolized cardiac devices and other foreign bodies is essential, yet no large studies have been reported in the paediatric population. Retrospective 15-year review of all children who underwent transcatheter foreign body retrieval in a tertiary cardiac centre from January 1997 to September 2012. Transcatheter retrieval of foreign bodies from the cardiovascular system was attempted in 78 patients [median age 4 (0.02–16) years and median weight 15 (1.7–74) kg] including 46 embolized devices. Transcatheter retrieval was successful in 70/78 (90%), surgical retrieval was required in 6. In two patients, small embolized coils were left in situ. Gooseneck snare was the most commonly used retrieval device. Median procedure and screening times were 90 (15–316) and 31 (2–161) min, respectively. There were no procedural deaths. Transient loss of foot pulses occurred in 5 and 2 patients required blood transfusion. Transcatheter retrieval of cardiovascular foreign bodies can be performed safely in the majority of children thus obviating the need for surgery. It is essential to have a comprehensive inventory of retrieval equipment and interventional staff conversant with its use.

Surgical management of hypoplastic left heart syndrome at the Birmingham Children's Hospital

Currently, a three-stage surgical palliation remains the treatment of choice at Birmingham Childrens Hospital. After initial introduction of the classical Norwood with pulmonary blood flow provided by a modified Blalock-Taussig shunt, a right ventricular to right pulmonary artery conduit at stage 1 Norwood palliation is now used in most cases, a bi-directional Glenn shunt at second stage and an extra-cardiac Fontan completion at third stage. Mortality and morbidity has improved after modification of the technique. Thirty-day mortality was 32.4% (79/244) for the classical Norwood procedure, 25.0% (7/28) for the left-sided RV-PA conduit and 12.7% (22/173) for the right-sided RV-PA conduit. Interstage mortality was 8.6% (21/244) for the classical Norwood procedure, 14.3% (4/28) for the left and 10.1% (15/148) for right-sided RV-PA conduit. After stage II, 30-day mortality was 3.0% (10/335) for all groups. Stage III 30-day mortality was 0.9% (1/115) for all groups.