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Biomedical subjects

Robert C Tasker

Publications and source records attributed to Robert C Tasker.

14 recordsLinked to original sources
PubMed2006

Intracranial pressure complicating severe traumatic brain injury in children: monitoring and management.

OBJECTIVE: To identify factors associated with the use of intracranial pressure (ICP) monitoring and to establish which ICP-targetted therapies are being used in children with severe traumatic brain injury (TBI) in the United Kingdom. To evaluate current practice against recently published guidelines. DESIGN AND SETTING: Prospective data collection of clinical and demographic information from paediatric and adult intensive care units in the UK and Ireland admitting children (< 16 years) with TBI between February 2001 and August 2003. RESULTS: Detailed clinical information was obtained for 501 children, with information on the use of ICP monitoring available in 445. ICP monitoring was used in only 59% (75/127) of children presenting with an emergency room Glasgow Coma Scale of 8 or below. Large between centre variation was seen in the use of ICP monitoring, independent of severity of injury. There were 86 children who received ICP-targetted therapies without ICP monitoring. Wide between centre variation was found in the use of ICP-targetted therapies and in general aspects of management, such as fluid restriction, the use of muscle relaxants and prophylactic anticonvulsants. Intra-ventricular catheters are rarely placed (6% of cases); therefore cerebrospinal fluid drainage is seldom used as a first-line therapy for raised ICP. Jugular venous bulb oximetry (4%), brain microdialysis (< 1%) and brain tissue oxygen monitoring (< 1%) are rarely used in current practice. Contrary to published guidelines, moderate to severe hyperventilation is being used without monitoring for cerebral ischaemia. CONCLUSIONS: There is an urgent need for greater standardisation of practice across UK centres admitting children with severe TBI.

Adolescent↗
PubMed2005

Head circumference and brain and hippocampal volume after severe traumatic brain injury in childhood.

Vulnerability of the hippocampus to traumatic brain injury (TBI) in adults is related to severity of injury and white matter atrophy. The objectives of this study were to determine features of anthropometry and cerebral morphometry late after TBI in childhood and to assess whether hippocampal volume is related to severity of initial ictus and changes in white matter at follow-up. Thirty-three patients underwent magnetic resonance imaging 4.9 y after severe TBI that necessitated intensive care; 23 had mechanical ventilation and intracranial pressure monitoring longer than 3 d. Magnetic resonance imaging analyses included volume of brain, hemisphere, ventricles, and hippocampal and perihippocampal regions; spatial distribution of voxel-based morphometry differences in white matter; and eigenvalues of diffusion tensor imaging diffusivity. Patients with longer intensive care ictus had smaller-than-expected occipitofrontal head circumference. Eight of these, identified by voxel-based morphometry, had periventricular white matter loss and smaller-than-expected brain volume for OFC, suggesting "atrophy"; the remainder had expected volume for a smaller OFC, suggesting "growth disturbance." Ninety-three percent of the variation in right hippocampal volume was accounted for by factors related to severity of injury and white matter atrophy. It is concluded that anthropometry and cerebral morphometric measurements late after severe TBI in childhood provides useful outcome data and indicate that, despite adequate growth in stature, effects of TBI on brain growth and hippocampal volume may extend into adulthood.

Adolescent↗
PubMed2005

A critical appraisal of a systematic review: Sokol J, Jacob SE, Bohn D: Inhaled nitric oxide for acute hypoxemic respiratory failure in children and adults. Cochrane Database Syst Rev 2003 (1): CD002787.

OBJECTIVE: To review the findings and discuss the implications of the use of inhaled nitric oxide for acute hypoxemic respiratory failure in patients beyond the neonatal period. DESIGN: A critical appraisal of a systematic review. FINDINGS: The authors conducted a systematic review with meta-analysis to determine the effect of inhaled nitric oxide on clinical outcomes of patients with acute hypoxemic respiratory failure. The outcomes included mortality, changes in oxygenation, ventilator-free days, duration of intensive care and hospital stays, and adverse effects. It was a high-quality systematic review provided with strict entry criteria, an extensive literature search, and thorough critical appraisals. Only five trials (n = 623) met entry criteria. Inhaled nitric oxide had no effect on mortality in studies without crossover of treatment failures to open-label inhaled nitric oxide (relative risk, 0.98; 95% confidence interval, 0.66-1.44). A statistically significant improvement in oxygenation was observed in one study. The effect, however, was observed only in the first 4 days of treatment and was not clinically significant. The heterogeneity in study findings precluded meta-analyses of other clinical outcomes and adverse effects in the selected studies. CONCLUSIONS: There is insufficient evidence to determine whether inhaled nitric oxide is beneficial or harmful for acute hypoxemic respiratory failure in children and adults. While awaiting further studies to prove its benefit, inhaled nitric oxide should not either be recommended as a standard management or excluded for the treatment of acute hypoxemic respiratory failure.

Adult↗
PubMed2005

Hyperventilation in severe diabetic ketoacidosis.

OBJECTIVE: To explore whether the carbon dioxide-bicarbonate (P(CO(2))-HCO(3)) buffering system in blood and cerebrospinal fluid (CSF) in diabetic ketoacidosis should influence the approach to ventilation in patients at risk of cerebral edema. DATA SOURCE: Medline search, manual search of references in articles found in Medline search, and use of historical literature from 1933 to 1967. DESIGN: A clinical vignette is used--a child with severe diabetic ketoacidosis who presented with profound hypocapnia and then deteriorated--as a basis for discussion of integrative metabolic and vascular physiology. STUDY SELECTION: Studies included reports in diabetic ketoacidosis where arterial and CSF acid-base data have been presented. Studies where simultaneous acid-base, ventilation, respiratory quotient, and cerebral blood flow data are available. DATA EXTRACTION AND SYNTHESIS: We revisit a hypothesis and, by reassessing data, put forward an argument based on the significance of low [HCO(3)](CSF) and rising Pa(CO(2))- hyperventilation in diabetic ketoacidosis and the limit in biology of survival; repair of severe diabetic ketoacidosis and Pa(CO(2))-and mechanical ventilation. CONCLUSION: The review highlights a potential problem with mechanical ventilation in severe diabetic ketoacidosis and suggests that the P(CO(2))--HCO(3) hypothesis is consistent with data on cerebral edema in diabetic ketoacidosis. It also indicates that the recommendation to avoid induced hyperventilation early in the course of intensive care may be counter to the logic of adaptive physiology.

Acid-Base Equilibrium↗
PubMed2004

The neuroendocrine stress response and severity of acute respiratory syncytial virus bronchiolitis in infancy.

OBJECTIVE: Neuroendocrine hormones have profound effects on the immune system. The immune response is a major factor in the pathogenesis of acute respiratory syncytial virus (RSV) infection. We hypothesised that there is a relationship between the neuroendocrine response in acute RSV infection, the severity of illness, and the degree of lymphopenia. DESIGN: Prospective, non-randomised cohort study of infants hospitalised for RSV infection requiring mechanical ventilation or managed conservatively. The study assessed the effect of age, gender, birth gestation, and severity of illness on stress hormone profile and its relationship to lymphocyte count. SETTING: Regional Paediatric Intensive Care Unit (PICU) and children's wards. PATIENTS: Thirty-two consecutive infants with RSV infection were enrolled, of which thirteen were mechanically ventilated on PICU (study subjects) and nineteen treated on the ward (comparison group). Twenty-three children (72%) returned for follow-up. MEASUREMENTS AND MAIN RESULTS: A specific neuroendocrine profile was found in PICU patients compared to ward patients (Wilks Lambda = 0.36, F = 9.05, P =.03). PICU patients had significantly higher prolactin and growth hormone, and significantly lower leptin and IGF-1. Cortisol levels were the same. PICU patients were more lymphopenic compared to ward patients (P =.0001). On multiple regression analysis, prolactin and leptin levels accounted for 57% of the variation in lymphocyte count. CONCLUSIONS: Whereas the effect of intensive care (mechanical ventilation and medication) could not be controlled for, our results suggest that there is an association between the neuroendocrine hormone response, severity of illness and degree of lymphopenia.

Acute Disease↗
PubMed2003

Respiratory viruses in the intensive care unit.

Respiratory viruses cause a number of clinical 'syndromes' in the intensive care unit with different viruses being able to produce similar clinical pictures. Our main presenting problems are upper airway (e.g. croup and tracheitis), lower airway with intrapulmonary shunt (e.g. bronchitis and pneumonia), lower airway with dynamic hyperinflation (e.g. bronchiolitis and wheeze) and control of breathing (e.g. apnoea). This pragmatic classification is used because it enables focus on the physiological abnormality needing treatment, and how best to deliver appropriate and adequate ventilator support. This review provides an overview of these syndromes and a more detailed account of respiratory syncytial virus, our most commonly diagnosed winter illness.

Child, Preschool↗
PubMed2002

Interactive effects of high-frequency oscillatory ventilation and inhaled nitric oxide in acute hypoxemic respiratory failure in pediatrics.

OBJECTIVE: High-frequency oscillatory ventilation (HFOV) and inhaled nitric oxide (iNO) have been reported to improve oxygenation in children with acute hypoxemic respiratory failure (AHRF), but their roles in the treatment of AHRF remains unknown. The use of HFOV improves oxygenation by increasing lung recruitment. iNO can improve oxygenation in AHRF, but it may have limited efficacy in patients with poor lung inflation. Based on these findings, we hypothesized that the combined treatment of HFOV and inhalation of low-dose NO would improve oxygenation and survival in children with severe AHRF compared with children treated with conventional mechanical ventilation (CMV) or either treatment alone. SETTING: Tertiary pediatric intensive care units at seven academic centers. DESIGN: Post hoc analysis of data from children enrolled in a multicenter, randomized, masked study of the use of iNO in the treatment of AHRF. PATIENTS: A total of 108 pediatric patients with AHRF defined as an oxygenation index of >15 twice within 6 hrs. Mode of ventilation (HFOV or CMV) was determined by the patient's physician based on guidelines to maximize oxygenation. The patient was then randomized to treatment with or without iNO. Comparisons were made between patients who were treated with HFOV plus iNO (n = 14), HFOV alone (n = 12), CMV plus iNO (n = 35), and CMV alone (n = 38). INTERVENTIONS: Ventilation with CMV or HFOV with or without iNO. MEASUREMENTS AND MAIN RESULTS: We found that the change in Pao /Fio ratio was greatest in the HFOV plus iNO group compared with the other treatment groups at 4 hrs (p =.02) and 12 hrs (p =.01). After 24 hrs of treatment, both HFOV plus iNO and HFOV alone resulted in greater improvement in Pao2/Fio2 ratio than either CMV alone or CMV plus iNO (p =.005). After 72 hrs, treatment with HFOV alone resulted in a greater improvement in Pao2/Fio2 ratio than either CMV alone or CMV plus iNO (p =.03). There was no difference in predefined treatment failures between treatment groups. CONCLUSIONS: We conclude that the combination of HFOV with iNO causes a greater improvement in oxygenation than either treatment strategy alone in children with severe AHRF. We speculate that the enhanced lung recruitment by HFOV enhances the effects of low dose iNO on gas exchange.

Administration, Inhalation↗