There is disagreement regarding the benefits of goal-directed therapy in moderate-risk abdominal surgery. Therefore, we tested the hypothesis that the addition of non-invasive cardiac index and pulse pressure variation monitoring to mean arterial pressure-based goal-directed therapy would reduce the incidence of postoperative complications in patients having moderate-risk abdominal surgery. In this pragmatic multicentre randomised controlled trial, we randomly allocated 244 patients by envelope drawing in a 1:1 fashion, stratified per centre. All patients had mean arterial pressure, cardiac index and pulse pressure variation measured continuously. In one group, healthcare professionals were blinded to cardiac index and pulse pressure variation values and were asked to guide haemodynamic therapy only based on mean arterial pressure (control group). In the second group, cardiac index and pulse pressure variation values were displayed and kept within target ranges following a pre-defined algorithm (CI-PPV group). The primary endpoint was the incidence of postoperative complications within 30 days. One hundred and seventy-five patients were eligible for final analysis. Overall complication rates were similar (42/94 (44.7%) vs. 38/81 (46.9%) in the control and CI-PPV groups, respectively; p = 0.95). The CI-PPV group had lower mean (SD) pulse pressure variation values (9.5 (2.0)% vs. 11.9 (4.6)%; p = 0.003) and higher mean (SD) cardiac indices (2.76 (0.62) l min .m vs. 2.53 (0.66) l min .m ; p = 0.004) than the control group. In moderate-risk abdominal surgery, we observed no additional value of cardiac index and pulse pressure variation-guided haemodynamic therapy to mean arterial pressure-guided volume therapy with regard to postoperative complications.

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The clinical application of manometry of the lower esophageal sphincter (LES) remains controversial. This is because of the large variability in recorded lower esophageal sphincter pressure (LESP). In this paper a computerized method providing a three-dimensional image of the LES is described. In 12 healthy subjects end-expiratory rapid pull-through LESP recordings were performed for 1 h, using a perfused 8-channel probe. A cylindric model of the sphincter was calculated by means of a graphics program. The graphic representation of the LES demonstrated a circular pressure zone that was affected by the gastric migrating motility complex. This pressure zone was located proximal to a persistent indentation in the posterior and right posterolateral direction. Three-dimensional visualization of the LES provides additional information that cannot be obtained by the usually used techniques of analysis of sphincter manometry.

The lower oesophageal sphincter (LES) is the main barrier against gastro-oesophageal reflux. Various anaesthetic drugs have been reported to affect the LES pressure. In this study, the effects of cisapride, atropine, suxamethonium, vecuronium and pancuronium on the LES pressure of six mongrel dogs anaesthetized with propofol and nitrous oxide were investigated. By means of eight-channel pressure profilometry the LES pressure was measured in consecutive sessions before and after administration of each drug. Compared to basal values, atropine and suxamethonium significantly decreased LES pressure, pressure vector volume and sphincter length. Cisapride significantly increased all sphincter parameters, vecuronium significantly increased LES pressure and pressure vector volume while pancuronium had no significant effects. A significant decrease of the LES pressure and pressure vector volume was observed when nitrous oxide was omitted from the ventilation mixture. Three-dimensional imaging showed an asymmetric shape of the LES pressure which resulted from radial differences of the LES pressure. The results from this study show that both the anaesthetic animal model and the eight-channel pressure profilometry are useful procedures in studying the effects on sphincter function of different drugs during anaesthesia.

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