Accuracy of bedside bidimensional transcranial ultrasound versus tomodensitometric measurement of the third ventricle.

BACKGROUND AND PURPOSE: To evaluate the accuracy of transcranial duplex sonography (TCS) for measuring the diameter of the third ventricle (DTV) and the brain midline shift (MLS), as compared to cerebral CT. METHODS: Single-center retrospective study including 177 patients admitted to the neurological intensive care unit (NICU). We studied the correlation between TCS and CT measurements of DTV and MLS using a Bland-Altman analysis. The best threshold of DTV to diagnose acute hydrocephalus was evaluated with a receiver operating characteristic (ROC) analysis. RESULTS: We analyzed 177 pairs of CT-TCS measurements for DTV and 165 for MLS. The mean time interval between CT and TCS was 87 ± 73 minutes. Median DTV measurement on CT was 4 ± 3 mm, and 5 ± 3 mm by TCS. Median MLS on CT was 2 ± 3 mm, and 2 ± 4 mm by TCS. The Pearson correlation coefficient (r2 ) was .96 between TCS and CT measurements (p < .001). The Bland-Altman analysis found a proportional bias of 0.69 mm for the DTV with a limit of agreement ranging between -3.04 and 2.53 mm. For the MLS, the proportional bias was 0.23 mm with limits of agreements between -3.5 and 3.95. The area under the ROC curve was .97 for the detection of hydrocephalus by DTV on TCS, with a best threshold of 5.72 mm (Sensitivity [Se] = 92% Specificity [Sp] = 92.1%). CONCLUSIONS: TCS seems to be a reliable and accurate bedside technique for measuring both DTV and MLS, which might allow detection of acute hydrocephalus among NICU patients.

Significance and Diagnostic Accuracy of Early S100B Serum Concentration after Aneurysmal Subarachnoid Hemorrhage.

BACKGROUND: Early brain injuries (EBI) are one of the most important causes of morbidity and mortality after subarachnoid hemorrhage. At admission, a third of patients are unconscious (spontaneously or sedated) and EBI consequences are not evaluable. To date, it is unclear who will still be comatose (with severe EBI) and who will recover (with less severe EBI) once the aneurysm is treated and sedation withdrawn. The objective of the present study was to determine the diagnostic accuracy of S100B levels at hospital admission to identify patients with severe neurological consequences of EBI. METHODS: Patients were consecutively included in this prospective blinded observational study. A motor component of the Glasgow coma score under 6 on day 3 was used to define patients with severe neurological consequences of EBI. RESULTS: A total of 81 patients were included: 25 patients were unconscious at admission, 68 were treated by coiling. On day 3, 12 patients had severe consequences of EBI. A maximal S100B value between admission and day 1 had an area under the receiver operating characteristic curve (AUC) of 86.7% to predict severe EBI consequences. In patients with impaired consciousness at admission, the AUC was 88.2%. CONCLUSION: Early S100B seems to have a good diagnostic value to predict severe EBI. Before claiming the usefulness of S100B as a surrogate marker of EBI severity to start earlier multimodal monitoring, these results must be confirmed in an independent validation cohort.

Comparison of heart rate response to an epinephrine test dose and painful stimulus in children during sevoflurane anesthesia: heart rate variability and beat-to-beat analysis.

BACKGROUND AND OBJECTIVES: During regional anesthesia, various stimuli leading to an adrenergic response can occur. However, simulation of an epidural test dose by using intravenous administration of epinephrine (EPI) has always been compared with an intravenous saline infusion as the control. The aim of this study was to evaluate the possibility of distinguishing in children the effect on HR by an intravascular epinephrine infusion and a painful stimulus, using heart rate variability (HRV) and beat-to-beat analysis of HR. METHODS: Thirty American Society of Anesthesiologists physical status P I children who required elective surgery were studied. At 1 minimum alveolar concentration (MAC) of sevoflurane, electrocardiogram was recorded continuously. Systolic blood pressure (SBP) was measured every minute. Measurements were performed after an intravenous administration of 0.5 microg/kg of epinephrine and during a small skin surgical incision (SI). Time-varying auto-regressive modeling of the interpolated RR sequences was performed for estimating power spectrum (msec(2)). The HF bands were defined by (0.15-0.4 Hz). RESULTS: Median (range) age and weight of all children were 3.5 (1-10) years and 16 (9-30) kg. EPI produced a lower increase in HR than did SI. SBP increased significantly more than did after SI. T-wave amplitude increased significantly after EPI but not after SI. Sixty seconds after the first change in HR, a secondary decrease (in comparison to control value) can be detected with EPI in contrast to SI. HF spectral power increased significantly after EPI administration but decreased after SI. The sensitivity, specificity, and positive and negative predictive value were respectively for DeltaHR >10 beats per minuteof 56%, 26%, 43%, and 38%; for DeltaSBP >15 mm Hg of 60%, 86%, 81%, and 67%; and for DeltaT-wave amplitude >25% of 86%, 73%, 76%, and 84%. Using detection of the secondary decrease of HR, 60 seconds after the first change in HR, sensitivity, specificity, and positive and a negative predictive value were respectively 96%, 100%, 100%, and 96%. CONCLUSIONS: Detection of the secondary HR decrease, 60 seconds after the first change in HR, allows us to distinguish the effects of a painful stimulus from those related to the epinephrine test dose at 1 MAC of sevoflurane. This secondary HR decrease induced by epinephrine appears primarily because of a compensatory increase in parasympathetic tone.