The safety of moderate hypothermic lower body circulatory arrest with selective cerebral perfusion: A propensity score analysis

ObjectiveThere is no common guideline on what temperature should be achieved at the lower body circulatory arrest followed by the initiation of selective cerebral perfusion.MethodsBetween October 1999 and August 2005, a total of 377 patients underwent repair of the aortic arch with selective cerebral perfusion and hypothermic circulatory arrest at 20°C to 28°C and were divided into two groups: (1) 125 patients with deep lower body circulatory arrest at 20°C to 24.9°C (deep lower body circulatory arrest group) and (2) 252 patients with moderate lower body circulatory arrest at 25°C to 28°C (moderate lower body circulatory arrest group). To compensate for the differences in patient characteristics, we used a propensity score matching analysis, and comparable patients, 92 patients from each group, were identified for final analysis.ResultsThere were no significant differences in mortality or morbidity between deep and moderate lower body circulatory arrest, in either the entire study cohort or the propensity-matched cohort. C-reactive protein level 1 day after the operation approached but fell short of significance (108.4 ± 47.7 mg/L in deep lower body circulatory arrest group and 95.8 ± 44.2 mg/L in moderate lower body circulatory arrest group, P = .07). The mean temperatures at the initiation of lower body circulatory arrest were 24.1°C ± 2.2°C in patients who underwent reexploration for bleeding and 24.9°C ± 1.8°C in patients who did not (P = .025); the difference also reached statistical significance in multivariate analysis (P = .046, odds ratio 0.796).ConclusionsOur results suggest that moderate lower body circulatory arrest can be safely performed for aortic arch repair. In fact, postoperative inflammatory response tended to be lower in patients with moderate lower body circulatory arrest than those with deep lower body circulatory arrest, and deep lower body circulatory arrest was a strong risk factor for reexploration for bleeding

Correlation of exhaled propofol with Narcotrend index and calculated propofol plasma levels in children undergoing surgery under total intravenous anesthesia - an observational study

Background!#!Exhaled propofol concentrations correlate with propofol concentrations in adult human blood and the brain tissue of rats, as well as with electroencephalography (EEG) based indices of anesthetic depth. The pharmacokinetics of propofol are however different in children compared to adults. The value of exhaled propofol measurements in pediatric anesthesia has not yet been investigated. Breathing system filters and breathing circuits can also interfere with the measurements. In this study, we investigated correlations between exhaled propofol (exP) concentrations and the Narkotrend Index (NI) as well as calculated propofol plasma concentrations.!##!Methods!#!A multi-capillary-column (MCC) combined with ion mobility spectrometry (IMS) was used to determine exP. Optimal positioning of breathing system filters (near-patient or patient-distant) and sample line (proximal or distal to filter) were investigated. Measurements were taken during induction (I), maintenance (M) and emergence (E) of children under total intravenous anesthesia (TIVA). Correlations between ExP concentrations and NI and predicted plasma propofol concentrations (using pediatric pharmacokinetic models Kataria and Paedfusor) were assessed using Pearson correlation and regression analysis.!##!Results!#!Near-patient positioning of breathing system filters led to continuously rising exP values when exP was measured proximal to the filters, and lower concentrations when exP was measured distal to the filters. The breathing system filters were therefore subsequently attached between the breathing system tubes and the inspiratory and expiratory limbs of the anesthetic machine. ExP concentrations significantly correlated with NI and propofol concentrations predicted by pharmacokinetic models during induction and maintenance of anesthesia. During emergence, exP significantly correlated with predicted propofol concentrations, but not with NI.!##!Conclusion!#!In this study, we demonstrated that exP correlates with calculated propofol concentrations and NI during induction and maintenance in pediatric patients. However, the correlations are highly variable and there are substantial obstacles: Without patient proximal placement of filters, the breathing circuit tubing must be changed after each patient, and furthermore, during ventilation, a considerable additional loss of heat and moisture can occur. Adhesion of propofol to plastic parts (endotracheal tube, breathing circle) may especially be problematic during emergence.!##!Trial registration!#!The study was registered in the German registry of clinical studies (DRKS-ID:  DRKS00015795 )

Intra-Abdominal Hypertension and Compartment Syndrome after Pediatric Liver Transplantation: Incidence, Risk Factors and Outcome

In pediatric liver transplantation (pLT), the risk for the manifestation and relevance of intra-abdominal hypertension (IAH) and abdominal compartment syndrome (ACS) is high. This observational study aimed to evaluate the incidence, relevance and risk factors for IAH and ACS by monitoring the intra-abdominal pressure (IAP), macro- and microcirculation (near-infrared spectroscopy (NIRS)), clinical and laboratory status and outcomes of 27 patients (16 female) after pLT (median age at pLT 35 months). Of the patients, 85% developed an elevated IAP, most of them mild. However, 17% achieved IAH° 3, 13% achieved IAH° 4 and 63% developed ACS. A multiple linear regression analysis identified aortal hepatic artery anastomosis and cold ischemia time (CIT) as risk factors for increased IAP and longer CIT and staged abdominal wall closure for ACS. ACS patients had significantly longer mechanical ventilation (p = 0.004) and LOS-PICU (p = 0.003). No significant correlation between NIRS or biliary complications and IAH or ACS could be shown. IAH and ACS after pLT were frequent. NIRS or grade of IAH alone should not be used for monitoring. A longer CIT is an important risk factor for higher IAP and ACS. Therefore, approaches such as the ex vivo machine perfusion of donor organs, reducing CIT effects on them, have great potential. Our study provides important basics for studying such approaches