Infections in the immunocompromised child.

Prevention and management of opportunistic infections in children is particularly relevant in an era demonstrating an increased prevalence of immunocompromising conditions. The presence of an unusual organism which results in serious infection in a child should therefore always raise the consideration of immune compromise. The more common opportunistic infections have become easier to recognize in recent times due to improved awareness and more refined diagnostic testing. Targeted treatment is usually followed by long-term prophylactic medication. The impact of these conditions on patient outcome is of clear significance and certainly warrants further discussion.

Targeted treatment in severe traumatic brain injury in the age of precision medicine.

In recent years, much progress has been made in our understanding of traumatic brain injury (TBI). Clinical outcomes have progressively improved, but evidence-based guidelines for how we manage patients remain surprisingly weak. The problem is that the many interventions and strategies that have been investigated in randomized controlled trials have all disappointed. These include many concepts that had become standard care in TBI. And that is just for adult TBI; in children, the situation is even worse. Not only is pediatric care more difficult than adult care because physiological norms change with age, but also there is less evidence for clinical practice. In this article, we discuss the heterogeneity inherent in TBI and why so many clinical trials have failed. We submit that a key goal for the future is to appreciate important clinical differences between patients in their pathophysiology and their responses to treatment. The challenge that faces us is how to rationally apply therapies based on the specific needs of an individual patient. In doing so, we may be able to apply the principles of precision medicine approaches to the patients we treat.

The effect of increased inspired fraction of oxygen on brain tissue oxygen tension in children with severe traumatic brain injury.

BACKGROUND: This study examines the effect of an increase in the inspired fraction of oxygen (FiO2) on brain tissue oxygen (PbO2) in children with severe traumatic brain injury (TBI). METHODS: A prospective observational study of patients who underwent PbO2 monitoring and an oxygen challenge test (temporary increase of FiO2 for 15 min) was undertaken. Pre- and post-test values for arterial partial pressure of oxygen (PaO2), PbO2, and arterial oxygen content (CaO2) were examined while controlling for any changes in arterial carbon dioxide tension and cerebral perfusion pressure during the test. Baseline transcranial Doppler studies were done. Outcome was assessed at 6 months. RESULTS: A total of 43 tests were performed in 28 patients. In 35 tests in 24 patients, the PbO2 monitor was in normal-appearing white matter and in eight tests in four patients, the monitor was in a pericontusional location. When catheters were pericontusional or in normal white matter the baseline PbO2/PaO2 ratio was similar. PaO2 (P < 0.0001) and PbO2 (P < 0.0001) significantly increased when FiO2 was increased. The magnitude of the PbO2 response (PbO2) was correlated with PaO2 (P < 0.0001, R(2) = 0.37) and CaO2 (P = 0.001, R(2) = 0.23). The PbO2/PaO2 ratio (oxygen reactivity) varied between patients, was related to the baseline PbO2 (P = 0.001, r = 0.54) and was inversely related to outcome (P = 0.02, confidence interval 0.03-0.78). CONCLUSION: Normobaric hyperoxia increases PbO2 in children with severe TBI, but the response is variable. The magnitude of this response is related to the change in PaO2 and the baseline PbO2. A greater response appears to be associated with worse outcome.