Acute effects of intracranial hypertension and ARDS on pulmonary and neuronal damage: a randomized experimental study in pigs

Abstract PURPOSE: To determine reciprocal and synergistic effects of acute intracranial hypertension and ARDS on neuronal and pulmonary damage and to define possible mechanisms. METHODS: Twenty-eight mechanically ventilated pigs were randomized to four groups of seven each: control; acute intracranial hypertension (AICH); acute respiratory distress syndrome (ARDS); acute respiratory distress syndrome in combination with acute intracranial hypertension (ARDS + AICH). AICH was induced with an intracranial balloon catheter and the inflation volume was adjusted to keep intracranial pressure (ICP) at 30-40 cmH2O. ARDS was induced by oleic acid infusion. Respiratory function, hemodynamics, extravascular lung water index (ELWI), lung and brain computed tomography (CT) scans, as well as inflammatory mediators, S100B, and neuronal serum enolase (NSE) were measured over a 4-h period. Lung and brain tissue were collected and examined at the end of the experiment. RESULTS: In both healthy and injured lungs, AICH caused increases in NSE and TNF-alpha plasma concentrations, extravascular lung water, and lung density in CT, the extent of poorly aerated (dystelectatic) and atelectatic lung regions, and an increase in the brain tissue water content. ARDS and AICH in combination induced damage in the hippocampus and decreased density in brain CT. CONCLUSIONS: AICH induces lung injury and also exacerbates pre-existing damage. Increased extravascular lung water is an early marker. ARDS has a detrimental effect on the brain and acts synergistically with intracranial hypertension to cause histological hippocampal damage

Potential Differences in Kidney Allograft Outcomes Between Ethnicities When Converting to Sirolimus Base Immunosuppression

OBJECTIVE: The aim of this study was to determine whether ethnicity impacts graft outcomes in kidney transplant patients converted to sirolimus (SRL) and maintained on either calcineurin inhibitors (CI) or mycophenolate mofetil (MMF) with steroids. METHODS: This study analyzed kidney transplants converted to SRL and transplanted between July 1991 and April 2007. Patients were divided into 4 groups: group 1: African-Americans converted to SRL + CI; group 2: non-African-Americans converted to SRL + CI; group 3: African-Americans converted to SRL + MMF; group 4: non-African-Americans converted to SRL + MMF. RESULTS: A total of 242 patients was included. Demographics, baseline immunosuppression, and reason for SRL conversion were similar among groups. Patients converted to SRL + CI regimens had significantly higher rates of acute rejection before SRL conversion, but equal rates after conversion. Development of proteinuria was similar across groups. African-American patients converted to SRL + MMF tended to have poorer outcomes compared with African-American patients converted to SRL + CI. Non-African-American patients converted to SRL + MMF tended to have better graft outcomes compared with non-African-American patients converted to SRL + CI. CONCLUSIONS: African-Americans converted to SRL may benefit from continued CI, whereas non-African-Americans converted to SRL seem to have better outcomes with MMF. Further prospective studies are warranted to confirm these findings