Near-Infrared Spectroscopy-Derived Dynamic Cerebral Autoregulation in Experimental Human Endotoxemia-An Exploratory Study.

Cerebral perfusion may be altered in sepsis patients. However, there are conflicting findings on cerebral autoregulation (CA) in healthy participants undergoing the experimental endotoxemia protocol, a proxy for systemic inflammation in sepsis. In the current study, a newly developed near-infrared spectroscopy (NIRS)-based CA index is investigated in an endotoxemia study population, together with an index of focal cerebral oxygenation. Methods: Continuous-wave NIRS data were obtained from 11 healthy participants receiving a continuous infusion of bacterial endotoxin for 3 h (ClinicalTrials.gov NCT02922673) under extensive physiological monitoring. Oxygenated-deoxygenated hemoglobin phase differences in the (very)low frequency (VLF/LF) bands and the Tissue Saturation Index (TSI) were calculated at baseline, during systemic inflammation, and at the end of the experiment 7 h after the initiation of endotoxin administration. Results: The median (inter-quartile range) LF phase difference was 16.2° (3.0-52.6°) at baseline and decreased to 3.9° (2.0-8.8°) at systemic inflammation (p = 0.03). The LF phase difference increased from systemic inflammation to 27.6° (12.7-67.5°) at the end of the experiment (p = 0.005). No significant changes in VLF phase difference were observed. The TSI (mean ± SD) increased from 63.7 ± 3.4% at baseline to 66.5 ± 2.8% during systemic inflammation (p = 0.03) and remained higher at the end of the experiment (67.1 ± 4.2%, p = 0.04). Further analysis did not reveal a major influence of changes in several covariates such as blood pressure, heart rate, PaCO2, and temperature, although some degree of interaction could not be excluded. Discussion: A reversible decrease in NIRS-derived cerebral autoregulation phase difference was seen after endotoxin infusion, with a small, sustained increase in TSI. These findings suggest that endotoxin administration in healthy participants reversibly impairs CA, accompanied by sustained microvascular vasodilation.

Middle cerebral artery flow, the critical closing pressure, and the optimal mean arterial pressure in comatose cardiac arrest survivors-An observational study.

AIM: This study estimated the critical closing pressure (CrCP) of the cerebrovascular circulation during the post-cardiac arrest syndrome and determined if CrCP differs between survivors and non-survivors. We also compared patients after cardiac arrest to normal controls. METHODS: A prospective observational study was performed at the ICU of a tertiary university hospital in Nijmegen, the Netherlands. We studied 11 comatose patients successfully resuscitated from a cardiac arrest and treated with mild therapeutic hypothermia and 10 normal control subjects. Mean flow velocity (MFV) in the middle cerebral artery was measured by transcranial Doppler at several time points after admission to the ICU. CrCP was determined by a cerebrovascular impedance model. RESULTS: MFV was similar in survivors and non-survivors upon admission to the ICU, but increased stronger in non-survivors compared to survivors throughout the observation period (P<0.001). MFV was significantly lower in survivors immediately after cardiac arrest compared to normal controls (P<0.001), with a gradual restoration toward normal values. CrCP decreased significantly from 61.4[51.0-77.1]mmHg to 41.7[39.9-51.0]mmHg in the first 48h, after which it remained stable (P<0.001). CrCP was significantly higher in survivors compared to non-survivors (P=0.002). CrCP immediately after cardiac arrest was significantly higher compared to the control group (P=0.02). CONCLUSIONS: CrCP is high after cardiac arrest with high cerebrovascular resistance and low MFV. This suggests that cerebral perfusion pressure should be maintained at a sufficient high level to avoid secondary brain injury. Failure to normalize the cerebrovascular profile may be a parameter of poor outcome.

An error in the CoaguChek S device results in prosthetic heart valve thrombosis.

The CoaguChek S device offers patients on oral anticoagulant treatment, a simple and fast method of direct monitoring of their international normalized ratio (INR). It is comparable with the glucose monitoring system, a fingerprick for a drop of capillary blood and some minutes to get the INR result for further anticoagulation monitoring. We present a case of tricuspid prosthetic valve thrombosis due to inadequate anticoagulation because of an error in the point-of-care device.

Risk of coronary surgery for hospital and early morbidity and mortality after initially successful percutaneous intervention.

This study examines the influence of a successful PCI upon preoperative patient profile, peroperative management and postoperative, including one-year follow-up, results. From January 1999 through December 2001, 1141 patients (91%) underwent coronary artery bypass grafting (CABG) as the primary intervention for myocardial revascularization (group A) and 113 patients (9%) underwent primary CABG after an initially successful PCI (group B). Patients undergoing CABG after a failed PCI were not included. Patients in group B were statistically significant younger (P=0.010), with more peripheral arterial vascular (P=0.015) and renal disease (P=0.036). Left main coronary artery stenosis was significantly lower in group B (P=0.004). The number of diseased vessels did not differ between the two groups. However, less distal anastomoses were performed in group B (P=0.001). Postoperatively there was no statistically significant differences, in the percentages of myocardial infarction, arrhythmias, reinterventions, neurological, renal and pulmonary complications, and hospital mortality. One-year follow-up did not show any statistically significant differences in cardiac related mortality (P=0.25) or recurrent ischemic events (P=0.27). Multivariate analysis did not identify a successful PCI as a risk factor for early and late adverse outcomes. Previous PCI does not seem to result in a higher postoperative mortality or morbidity after CABG.