Cerebral Hemodynamics and Levosimendan Use in Patients with Cerebral Vasospasm and Subarachnoid Hemorrhage: An Observational Perfusion CT-Based Imaging Study.

BACKGROUND: Delayed cerebral ischemia associated with cerebral vasospasm (CVS) in aneurysmal subarachnoid hemorrhage significantly affects patient prognosis. Levosimendan has emerged as a potential treatment, but clinical data are lacking. The aim of this study is to decipher levosimendan's effect on cerebral hemodynamics by automated quantitative measurements of brain computed tomography perfusion (CTP). METHODS: We conducted a retrospective analysis of a database of a neurosurgical intensive care unit. All patients admitted from January 2018 to July 2022 for aneurysmal subarachnoid hemorrhage and treated with levosimendan for CVS who did not respond to other therapies were included. Quantitative measurements of time to maximum (Tmax), relative cerebral blood volume (rCBV), and relative cerebral blood flow (rCBF) were automatically compared with coregistered CTP before and after levosimendan administration in oligemic regions. RESULTS: Of 21 patients included, CTP analysis could be performed in 16. Levosimendan improved Tmax from 14.4 s (interquartile range [IQR] 9.1-21) before treatment to 7.1 s (IQR 5.5-8.1) after treatment (p < 0.001). rCBV (94% [IQR 79-103] before treatment and 89% [IQR 72-103] after treatment, p = 0.63) and rCBF (85% [IQR 77-90] before treatment and 87% [IQR 73-98] after treatment, p = 0.98) remained stable. The subgroup of six patients who did not develop cerebral infarction attributed to delayed cerebral ischemia showed an approximately 10% increase (rCBV 85% [IQR 79-99] before treatment vs. 95% [IQR 88-112] after treatment, p = 0.21; rCBF 81% [IQR 76-87] before treatment vs. 89% [IQR 84-99] after treatment, p = 0.4). CONCLUSIONS: In refractory CVS, levosimendan use was associated with a significant reduction in Tmax in oligemic regions. However, this value remained at an abnormal level, indicating the presence of a persistent CVS. Further analysis raised the hypothesis that levosimendan causes cerebral vasodilation, but other studies are needed because our design does not allow us to quantify the effect of levosimendan from that of the natural evolution of CVS.

Use of Extracorporeal Membrane Oxygenation in Pneumocystis Pneumonia of an Infant with AIDS.

Pneumocystis pneumonia is a common complication of cellular immunosuppression and may trigger severe pulmonary complications. Rapid onset of acquired immunodeficiency syndrome is possible in infants infected with human immunodeficiency virus (HIV). We report here the case of a 13-week-old girl who was previously healthy presenting with altered immunity and refractory acute respiratory distress syndrome (ARDS) initially attributed to bacterial pneumonia. Venovenous extracorporeal membrane oxygenation (VV-ECMO) was initiated because her condition was poor. An HIV infection was later fortuitously diagnosed after accidental exposure of a nurse to the child's urine. The mother had congenitally transmitted HIV to the child after late (undetected) infection during pregnancy. The lung lesions were finally attributed to Pneumocystis pneumonia. We prescribed combined antiretroviral, antibiotic, and steroid therapy aimed at preventing immune reconstitution inflammatory syndrome. VV-ECMO weaning progressed over 30 days to the time of decannulation, rapidly followed by extubation and hospital discharge. The case highlights the fact that rare curable causes of refractory pediatric ARDS should always be investigated early. VV-ECMO should not be excluded as an ARDS treatment for immunocompromised children.

Salt wasting syndrome in brain trauma patients: a pathophysiologic approach using sodium balance and urinary biochemical analysis.

BACKGROUND: To explore the underlying mechanisms leading to the occurrence of hyponatremia and enhanced urinary sodium excretion in brain trauma patients using sodium balance and urinary biochemical analysis. METHODS: We conducted a retrospective analysis of a local database prospectively collected in 60 brain trauma patients without chronic renal dysfunction. Metabolic and hemodynamic parameters were averaged over three consecutive periods over the first seven days after admission. The main outcome investigated in this study was the occurrence of at least one episode of hyponatremia. RESULTS: Over the study period, there was a prompt decrease in sodium balance (163 ± 193 vs. -12 ± 154 mmol/day, p < 0.0001) and free water clearance (- 0.7 ± 0.7 vs. -1.8 ± 2.3 ml/min, p < 0.0001). The area under the ROC curves for sodium balance in predicting the occurrence of hyponatremia during the next period was 0.81 [95% CI: 0.64-0.97]. Variables associated with averaged urinary sodium excretion were sodium intake (R2 = 0.26, p < 0.0001) and fractional excretion of urate (R2 = 0.15, p = 0.009). Urinary sodium excretion was also higher in patients with sustained augmented renal clearance over the study period (318 ± 106 vs. 255 ± 135 mmol/day, p = 0.034). CONCLUSION: The decreased vascular volume resulting from a negative sodium balance is a major precipitating factor of hyponatremia in brain trauma patients. Predisposing factors for enhanced urinary sodium excretion were high sodium intake, high fractional excretion of urate and augmented renal clearance over the first seven days after ICU admission.

Evaluation of least significant changes of pulse contour analysis-derived parameters.

BACKGROUND: Many maneuvers assessing fluid responsiveness (minifluid challenge, lung recruitment maneuver, end-expiratory occlusion test, passive leg raising) are considered as positive when small variations in cardiac index, stroke volume index, stroke volume variation or pulse pressure variation occur. Pulse contour analysis allows continuous and real-time cardiac index, stroke volume, stroke volume variation and pulse pressure variation estimations. To use these maneuvers with pulse contour analysis, the knowledge of the minimal change that needs to be measured by a device to recognize a real change (least significant change) has to be studied. The aim of this study was to evaluate the least significant change of cardiac index, stroke volume index, stroke volume variation and pulse pressure variation obtained using pulse contour analysis (ProAQT®, Pulsion Medical System, Germany). METHODS: In this observational study, we included 50 mechanically ventilated patients undergoing neurosurgery in the operating room. Cardiac index, stroke volume index, pulse pressure variation and stroke volume variation obtained using ProAQT® (Pulsion Medical System, Germany) were recorded every 12 s during 15-min steady-state periods. Least significant changes were calculated every minute. RESULTS: Least significant changes statistically differed over time for cardiac index, stroke volume index, pulse pressure variation and stroke volume variation (p < 0.001). Least significant changes ranged from 1.3 to 0.7% for cardiac index, from 1.3 to 0.8% for stroke volume index, from 10 to 4.9% for pulse pressure variation and from 10.8 to 4.3% for stroke volume variation. CONCLUSION: To conclude, the present study suggests that pulse contour analysis is able to detect rapid and small changes in cardiac index and stroke volume index, but the interpretation of rapid and small changes of pulse pressure variation and stroke volume variation must be done with caution.