Vancomycin-resistant enterococcus outbreak in a pediatric intensive care unit: report of successful interventions for control and prevention

The objective of this study is to retrospectively report the results of interventions for controlling a vancomycin-resistant enterococcus (VRE) outbreak in a tertiary-care pediatric intensive care unit (PICU) of a University Hospital. After identification of the outbreak, interventions were made at the following levels: patient care, microbiological surveillance, and medical and nursing staff training. Data were collected from computer-based databases and from the electronic prescription system. Vancomycin use progressively increased after March 2008, peaking in August 2009. Five cases of VRE infection were identified, with 3 deaths. After the interventions, we noted a significant reduction in vancomycin prescription and use (75% reduction), and the last case of VRE infection was identified 4 months later. The survivors remained colonized until hospital discharge. After interventions there was a transient increase in PICU length-of-stay and mortality. Since then, the use of vancomycin has remained relatively constant and strict, no other cases of VRE infection or colonization have been identified and length-of-stay and mortality returned to baseline. In conclusion, we showed that a bundle intervention aiming at a strict control of vancomycin use and full compliance with the Hospital Infection Control Practices Advisory Committee guidelines, along with contact precautions and hand-hygiene promotion, can be effective in reducing vancomycin use and the emergence and spread of vancomycin-resistant bacteria in a tertiary-care PICU.

Growth after ventricular septal defect repair: does defect size matter? A 10-year experience

AIM

To evaluate whether the ventricular septal defect (VSD) size, along with the degree of preoperative growth impairment and age at repair, may influence postoperative growth, and if VSD size can be useful to identify children at risk for preoperative failure to thrive.

METHODS

Sixty-eight children submitted to VSD repair in a Brazilian tertiary-care institution were evaluated. Weight and height measurements were converted to Z-scores. Ventricular septal defect size was normalized by dividing it by the aortic root diameter (VSD/Ao ratio).

RESULTS

Twenty-six patients (38%) had significantly low weight-for-height, 10 patients (15%) had significantly low height-for-age and 13 patients (19%) had both conditions at repair. Catch-up growth occurred in 82% of patients for weight-for-age, in 75% of patients for height-for-age and in 89% of patients for weight-for-height. Weight-for-height Z-scores at surgery were significantly lower in patients who underwent repair before 9 months of age. The VSD/Ao ratio did not associate with any other data. On multivariate analysis, weight-for-age Z-scores and age at surgery were independent predictors of long-term weight and height respectively.

CONCLUSION

The VSD/Ao ratio was not a good predictor of preoperative failure to thrive. Most patients had preoperative growth impairment and presented catch-up growth after repair. Preoperative growth status and age at surgery influenced long-term growth.

Indicators of lean body mass catabolism: emphasis on the creatinine excretion rate

BACKGROUND

The major stress response to critical illness leads to a catabolic state and loss of lean body mass.

AIMS

To test whether an increased rate of creatinine excretion might provide unique and timely information to monitor cell catabolism; to relate this information to balances of cell constituents (nitrogen, potassium, phosphate and magnesium); to evaluate the effectiveness of nutritional therapy to reverse this catabolic process.

DESIGN

Prospective observational study.

METHODS

Children with severe traumatic brain injury admitted to the paediatric critical care units of The Hospital for Sick Children, Toronto, Canada and Hospital das Clínicas, Faculty of Medicine of Ribeirão Preto, University of São Paulo, Brazil were studied. Complete 24 h urine collections were obtained for measurement of creatinine excretion rate and daily balances of nitrogen, potassium, phosphate and magnesium.

RESULTS

Seventeen patients were studied for 3-10 days. On Day 1, all had negative balances for protein and phosphate. Balances for these intracellular constituents became positive when protein intake was >/=1 g/kg/day and energy intake was >/=50% of estimated energy expenditure (P < 0.0001). Creatinine excretion rate was positively correlated with the urea appearance rate (r = 0.60; P < 0.0001), and negatively with protein balance (r = -0.45; P < 0.0001). Sepsis developed in four patients; before its clinical detection, there were negative balances for all intracellular markers and an abrupt rise in the excretion of creatinine.

CONCLUSION

Negative balances of intracellular components and an increase in rate of creatinine excretion heralded the onset of catabolism.

Uncovering the basis of a severe degree of acidemia in a patient with diabetic ketoacidosis

In this teaching exercise, the goal is to demonstrate how an application of principles of physiology can reveal the basis for a severe degree of acidaemia (pH 6.81, bicarbonate <3 mmol/l (P(HCO(3))), PCO(2) 8 mmHg), why it was tolerated for a long period of time, and the issues for its therapy in an 8-year-old female with diabetic ketoacidosis. The relatively low value for the anion gap in plasma (19 mEq/l) suggested that its cause was both a direct and an indirect loss of NaHCO(3). Professor McCance suggested that ileus due to hypokalaemia might cause this direct loss of NaHCO(3), and that an excessive excretion of ketoacid anions without NH(4)(+) in the urine accounted for the indirect loss of NaHCO(3). In addition, he suspected that another factor also contributing to the severity of the acidaemia was a low input of alkali. He was also able to explain why there was a 16-h delay before there was a rise in the P(HCO(3)) once therapy began. The missing links in this interesting story, including a possible basis for the hypokalaemia, emerge during the discussion between the medical team and Professor McCance.

A hyperglycaemic hyperosmolar state in a young child: diagnostic insights from a quantitative analysis

This teaching exercise demonstrates how the application of principles of physiology can identify the cause of a severe degree of hyperglycaemia (plasma glucose concentration 80 mmol/l) in a very young patient with newly diagnosed diabetes mellitus, determine whether the patient has diabetic ketoacidosis, and highlight the potential risks for this patient on admission and during initial therapy. A consultation with Professor McCance was sought to determine whether this patient had an unusual degree of 'insulin resistance'. There were also uncertainties regarding the acid-base diagnosis. The patient did not appear to have an important degree of metabolic acidosis as judged from his pH of 7.39 and plasma bicarbonate concentration of 20 mmol/l in arterial blood; hence the diagnostic impression was that he had a hyperglycaemic hyperosmolar state. However, his plasma anion gap was significantly elevated, and remained so for 60 h, despite the administration of insulin. Issues in management concerning the basis for this severe degree of hyperglycaemia and how to minimize the risk of developing cerebral oedema are addressed. The missing links in this interesting story emerge during a discussion between the medical team and their mentor, Professor McCance.

Importance of timing of risk factors for cerebral oedema during therapy for diabetic ketoacidosis

Cerebral oedema is the most common cause of mortality and morbidity during the first day of conventional treatment for diabetic ketoacidosis in paediatric patients. It is possible that therapy contributes to its development. Risk factors that predispose to cerebral oedema should lead to an expansion of the intracellular and/or the extracellular fluid compartment(s) of the brain because water normally accounts for close to 80% of brain weight. With respect to the intracellular fluid compartment, the driving force to cause cell swelling is a gain of effective osmoles in brain cells and/or a significant decline in the effective osmolality of the extracellular fluid compartment. Factors leading to an expansion of the intracerebral extracellular fluid volume can be predicted from Starling forces acting at the blood-brain barrier. Some of these risk factors have an early impact, while others have their major effects later during therapy for diabetic ketoacidosis. Based on a theoretical analysis, suggestions to modify current therapy for diabetic ketoacidosis in children are provided.