Mike South

Early markers of major adverse events in children after cardiac operations

OBJECTIVES The purpose of this study was to determine the physiologic variables that predict major adverse events in children in the intensive care unit after cardiac operations. METHODS A cohort observational study was conducted. At the time of admission to the intensive care unit and 4, 8, 12, and 24 hours later the following variables were recorded: mean arterial pressure, heart rate, cardiac index, oxygen delivery, mixed venous oxygen saturation, base deficit, blood lactate, gastric intramucosal pH, carbon dioxide difference (the difference between arterial carbon dioxide tension and gastric intraluminal carbon dioxide tension), and toe-core temperature gradient. Major adverse events were prospectively identified as cardiac arrest, need for emergency chest opening, development of multiple organ failure, and death. RESULTS Ninety children were included in the study; 12 had major adverse events and there were 4 deaths. Blood lactate level, mean arterial pressure, and duration of cardiopulmonary bypass were the only significant, independent predictors of major adverse events when measured at the time of admission to the intensive care unit. The odds ratio (95% confidence intervals) for major adverse events if a lactate level was greater than 4.5 mmol/L was 5.1 (1.2 to 21.1), for admission hypotension 2.3 (0.5 to 9.8), and for a cardiopulmonary bypass time greater than 150 minutes 13.7 (3.3 to 57.2). Four hours after admission lactate and carbon dioxide difference, and 8 hours after admission lactate and base deficit, were independently significant predictors. The odds ratios for major adverse events if the blood lactate level was greater than 4 mmol/L at 4 and 8 hours were 8.3 (1.8 to 38.4) and 9.3 (1.9 to 44.3), respectively. At no time in the first 24 hours were cardiac output, oxygen delivery, mixed venous oxygen saturation, toe-core temperature gradient, or heart rate significant predictors of major adverse events. CONCLUSIONS In the context of our current treatment strategies, the duration of cardiopulmonary bypass and blood lactate level, measured in the early postoperative period, were the best predictors of impending major adverse events.

Predictors of mortality and multiple organ failure in children with sepsis

Objectives: To assess the markers of perfusion which best discriminate survivors from non-survivors of childhood sepsis and to compare the information derived from gastric tonometry with conventionally measured haemodynamic and laboratory parameters. Design: Prospective clinical study of children with sepsis syndrome or septic shock. Setting: Paediatric intensive care unit in a tertiary referral centre. Patients: 31 children with sepsis syndrome or septic shock. Interventions: A tonometer was passed into the stomach via the orogastric route. Measurements and main results: The following data were recorded at admission, 12, 24 and 48 h: heart rate, mean arterial pressure, arterial pH, base deficit, arterial lactate, gastric intramucosal pH (pHi) and DCO2 (intramucosal carbon dioxide tension minus arterial partial pressure of carbon dioxide). The principal outcome measure was survival. The secondary outcome measure was the number of organ systems failing at 48 h after admission. There were 10 deaths and 21 survivors. No variable discriminated survival from death at presentation. Blood lactate level was the earliest discriminator of survival. Using univariate logistic regression, lactate discriminated survivors from those who died at 12 and 24 h after admission, but not at 48 h (p = 0.049, 0.044 and 0.062, respectively). The area under the receiver operating characteristic (ROC) curve for lactate was 0.81, 0.88 and 0.89 at 12, 24 and 48 h, respectively. At 12 h after admission, a blood lactate level > 3 mmol/l had a positive predictive value for death of 56 % and a lactate level of 3 mmol/l or less had a positive predictive value for survival of 84 %. At 24 h a lactate level > 3 mmol/l had a positive predictive value for death of 71 % and a level of 3 mmol/l or less had a positive predictive value for survival of 86 %. No other variable identified non-survivors from survivors at 12 h. Gastric tonometry could only be done on 19 of the 31 children, of whom 8 died and 11 survived. In these 19 children, DCO2 measured at 24 h, but not at 12 or 48 h, distinguished those who died from those who survived (p = 0.045 and p = 0.20, respectively). The area under the ROC curve for DCO2 measured at 24 h as a predictor of survival was 0.71. Neither the absolute value of pHi nor the trend of change in pHi at any time in the first 48 h identified survivors in this series. The mean arterial pressure distinguished survivors from non-survivors at 24 and 48 h (area under ROC curve = 0.80 and 0.78, respectively). The base deficit and heart rate did not identify non-survivors from survivors at any time in the first 48 h. Conclusions: Blood lactate level was the earliest predictor of outcome in children with sepsis. In this group of patients, gastric tonometry added little to the clinical information that could be derived more simply by other means.

Randomised controlled trial of aminophylline for severe acute asthma

OBJECTIVES To determine whether children with severe acute asthma treated with large doses of inhaled salbutamol, inhaled ipratropium, and intravenous steroids are conferred any further benefits by the addition of aminophylline given intravenously. STUDY DESIGN Randomised, double blind, placebo controlled trial of 163 children admitted to hospital with asthma who were unresponsive to nebulised salbutamol. RESULTS The placebo and treatment groups of children were similar at baseline. The 48 children in the aminophylline group had a greater improvement in spirometry at six hours and a higher oxygen saturation in the first 30 hours. Five subjects in the placebo group were intubated and ventilated after enrolment compared with none in the aminophylline group. CONCLUSIONS Aminophylline continues to have a place in the management of severe acute asthma in children unresponsive to initial treatment.

Surfactant abnormalities in infants with severe viral bronchiolitis.

To determine whether abnormalities of pulmonary surfactant occur in infants with acute viral bronchiolitis, surfactant indices were measured in lung lavage fluid from 12 infants with severe bronchiolitis and eight infants without lung disease. Compared with controls, the bronchiolitis group showed deficiency of surfactant protein A (1.02 v 14.4 micrograms/ml) and disaturated phosphatidylcholine (35 v 1060 micrograms/ml) which resolved as the disease improved. Surfactant functional activity was also impaired (minimum surface tension 22 v 17 mN/m). These findings indicate that surfactant abnormalities occur in bronchiolitis, and may represent one of the pathophysiological mechanisms causing airway obstruction.

Cerebral blood flow velocity variability in infants receiving assisted ventilation.

Cerebral blood flow velocity was measured using Doppler ultrasonography in 20 babies who weighed less than 2500 g at birth and who were receiving assisted ventilation; their patterns of spontaneous respiration were recorded simultaneously. The babies were induced to breathe synchronously or asynchronously with the ventilator by manipulating the inspiratory and expiratory time settings. The variability of cerebral blood flow velocity (coefficient of variation) was calculated from the area of the maximum Doppler frequency shift envelope for 10 cardiac cycles from 211 recordings made on 42 occasions, and was greatest within 12 hours of birth after which it fell progressively over the next 48 hours. Variability of cerebral blood flow velocity was significantly greater when the infants were breathing out of synchrony with the ventilator (median 11%, interquartile range 8-14%) than when they were either apnoeic (median 5%, 3-7%), or breathing synchronously with the ventilator (median 5%, 3-6%).

Survey of complementary and alternative medicine use at a tertiary children's hospital

Objective: The use of complementary and alternative medicine (CAM) within the Australian community is common. The objective of this study was to determine the prevalence and pattern of CAM usage in children attending a tertiary childrens hospital.

Comparison of complementary and alternative medicine use: reasons and motivations between two tertiary children’s hospitals

Aims: To compare prevalence, reasons, motivations, initiation, perceived helpfulness, and communication of complementary and alternative medicine (CAM) use between two tertiary children’s hospitals. Methodology: A study, using a face-to-face questionnaire, of 500 children attending the University Hospital of Wales, Cardiff, UK was compared to an identical study of 503 children attending the Royal Children’s Hospital, Melbourne, Australia. Results: One year CAM use in Cardiff was lower than Melbourne (41% v 51%; OR = 0.67, 95% CI 0.52–0.85), reflected in non-medicinal use (OR = 0.41, 95% CI 0.29–0.58) and general paediatric outpatients (OR = 0.38, 95% CI 0.21–0.67). Compared to Melbourne, factors associated with lower CAM use in Cardiff included families born locally (father: OR = 0.58, 95% CI 0.44–0.77) or non-tertiary educated parents (mother: OR = 0.54, 95% CI 0.38–0.77). Cardiff participants used less vitamin C (OR = 0.31, 95% CI 0.18–0.51) and herbs (OR = 0.49, 95% CI 0.34–0.71), attended less chiropractors (OR = 0.25, 95% CI 0.06–0.37) and naturopaths (OR = 0.08, 95% CI 0.02–0.33), but saw more reflexologists (OR = 3.33, 95% CI 1.08–10.29). In Cardiff, CAM was more popular for relaxation (OR = 1.92, 95% CI 1.03–3.57) but less for colds/coughs (OR = 0.4, 95% CI 0.27–0.73). Most CAM was self-initiated (by parent) in Cardiff and Melbourne (74% v 70%), but Cardiff CAM users perceived it less helpful (OR = 0.46, 95% CI 0.31–0.68). Non-disclosure of CAM use was high in Cardiff and Melbourne (66% v 63%); likewise few doctors/nurses documented recent medicinal CAM use in inpatient notes (0/21 v 2/22). Conclusions: The differences in CAM use may reflect variation in sociocultural factors influencing reasons, motivations, attitudes, and availability. The regional variation in use and poor communication highlights the importance of local policy development.

Agreement of aspiration tests using barium videofluoroscopy, salivagram, and milk scan in children with cerebral palsy

To study the agreement between three tests for aspiration, barium videofluoroscopy, salivagram, and milk scan we studied 63 children with severe non-ambulant spastic quadriplegic cerebral palsy (CP) aged 14 months to 16 years (32 males, 31 females). The salivagram was most frequently positive (56%, 95% confidence interval 43 to 68%); the next most frequently positive was barium videofluoroscopy when aspiration was defined as the presence of either laryngeal penetration of material or frank aspiration (39%, 95% confidence interval 26 to 53%). The milk scan was rarely positive (6%, 95% confidence interval 2 to 16%). Agreement between the tests of aspiration was poor. The maximum agreement (kappa=0.20) was between aspiration as diagnosed with the salivagram and by barium videofluoroscopy. Positive tests for aspiration are frequent in children with severe CP. Frequency varies widely depending on the investigation used. There is poor agreement between tests used for the diagnosis of aspiration. This information is of importance in assessing the significance of test results.

Successful implementation of spacer treatment guideline for acute asthma

AIMS To develop and implement an evidence based guideline for the treatment of acute asthma using a metered dose inhaler and spacer combination. METHODS Defined strategies were used for the development and implementation of a guideline, assessed by a prospective, descriptive, study using notes review, and patient, nursing, and medical staff telephone contact. The setting was a tertiary referral hospital in Victoria, Australia with 25 000 yearly admissions, and asthma accounting for about 7% of total. The first 200 children and families to use the guideline after its introduction were evaluated. RESULTS A total of 191 (95.5%) children were treated according to the guideline. Six (3.0%) children were given nebulisers appropriately based on severity; five (2.5%) were given nebulisers at parental or child choice; and four (2.0 %) who did not have severe asthma, received nebulised treatment inappropriately. CONCLUSIONS Successful implementation of a new evidence based guideline can be achieved using specific strategies for promoting the application of research findings in the clinical arena.

140 mmol/L of sodium versus 77 mmol/L of sodium in maintenance intravenous fluid therapy for children in hospital (PIMS): a randomised controlled double-blind trial

BACKGROUND Use of hypotonic intravenous fluid to maintain hydration in children in hospital has been associated with hyponatraemia, leading to neurological morbidity and mortality. We aimed to assess whether use of fluid solutions with a higher sodium concentration reduced the risk of hyponatraemia compared with use of hypotonic solutions. METHODS We did a randomised controlled double-blind trial of children admitted to The Royal Childrens Hospital (Melbourne, VIC, Australia) who needed intravenous maintenance hydration for 6 h or longer. With an online randomisation system that used unequal block sizes, we randomly assigned patients (1:1) to receive either isotonic intravenous fluid containing 140 mmol/L of sodium (Na140) or hypotonic fluid containing 77 mmol/L of sodium (Na77) for 72 h or until their intravenous fluid rate decreased to lower than 50% of the standard maintenance rate. We stratified assignment by baseline sodium concentrations. Study investigators, treating clinicians, nurses, and patients were masked to treatment assignment. The primary outcome was occurrence of hyponatraemia (serum sodium concentration <135 mmol/L with a decrease of at least 3 mmol/L from baseline) during the treatment period, analysed by intention to treat. The trial was registered with the Australian New Zealand Clinical Trials Registry, number ACTRN1260900924257. FINDINGS Between Feb 2, 2010, and Jan 29, 2013, we randomly assigned 690 patients. Of these patients, primary outcome data were available for 319 who received Na140 and 322 who received Na77. Fewer patients given Na140 than those given Na77 developed hyponatraemia (12 patients [4%] vs 35 [11%]; odds ratio [OR] 0·31, 95% CI 0·16-0·61; p=0·001). No clinically apparent cerebral oedema occurred in either group. Eight patients in the Na140 group (two potentially related to intravenous fluid) and four in the Na77 group (none related to intravenous fluid) developed serious adverse events during the treatment period. One patient in the Na140 had seizures during the treatment period compared with seven who received Na77. INTERPRETATION Use of isotonic intravenous fluid with a sodium concentration of 140 mmol/L had a lower risk of hyponatraemia without an increase in adverse effects than did fluid containing 77 mmol/L of sodium. An isotonic fluid should be used as intravenous fluid for maintenance hydration in children. FUNDING National Health and Medical Research Council, Murdoch Childrens Research Institute, The Royal Childrens Hospital, and the Australian and New Zealand College of Anaesthetists.