Breath tests using (13)C-labelled substrates require the measurement of (13)CO(2)/(12)CO(2) ratio in breath gas samples. Next to isotope ratio mass spectrometry (IRMS), which is very sensitive but also complex and expensive, alternatively isotope selective nondispersive infrared spectrometry (NDIRS) can be used to determine the (13)CO(2)/(12)CO(2) ratio in expired breath. In this study we compared NDIRS- with IRMS-results to investigate whether the less expensive and very simply to operate NDIRS works as reliable as IRMS. For this purpose we applicated 1-(13)C-Phenylalanine to patients with advanced liver cirrhosis and healthy volunteers and took duplicated breath samples for IRMS and NDIRS at selected time points. Our data show a good correlation between these two methods for a small number of samples as required for simple breath tests. Longer series, where repeated measurements are required on the NDIRS instrument lead to a decreasing correlation. This indicates the superiority of IRMS concerning (13)CO(2)-kinetics over longer time periods.

We conclude that an increased ileal-mucosal-arterial delta PCO2 during porcine endotoxemia is related to impaired villus microcirculation. A putative contribution of disturbed cellular oxygen utilization resulting from "cytopathic hypoxia" may also assume importance.

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SummaryThe use of periclavicular brachial plexus block as regional anaesthesia for surgical procedures on the upper extremity is common. However, the proximity of the pleura results in a risk of pneumothorax. Without ultrasound monitoring, the pneumothorax risk has been reported to be as high as 6.1%. We conducted a prospective, observational study to examine the risk of pneumothorax in 6366 ultrasound-guided periclavicular plexus blocks. All patients with a clinically manifest and radiologically confirmed pneumothorax were analysed. Clinically symptomatic pneumothorax occurred in four patients (0.06%; 95% CI 0.001-0.124), in three of them after a two-day latency period. Ultrasound guidance does therefore appear to reduce the risk of pneumothorax. Although all of the anaesthesiologists involved in the complications had previously performed fewer than 20 blocks, we are not able to confirm that a block experience ≤ 20 is a significant risk factor. Faulty image-setting, inability to obtain a view of the needle tip and inadequate supervision are likely to be important risk factors.

In patients with septic shock an iloprost-induced increase in cardiac index increased splanchnic blood flow and shifted oxygen utilization from the energy requiring de novo glucose production rate to other oxygen-demanding metabolic pathways.