This study confirmed the acute vasoconstrictive and positive inotropic effects of methylene blue during septic shock. These effects were not associated with changes in blood volume, myocardial diastolic function, or pulmonary vascular permeability assessed by extravascular lung water.
BackgroundIn vascular surgery with aortic cross-clamping, ischemia/reperfusion injury induces systemic haemodynamic and microcirculatory disturbances. Different anaesthetic regimens may have a varying impact on tissue perfusion. The aim of this study was to explore changes in microvascular perfusion in patients undergoing elective open abdominal aortic aneurysm repair under balanced or total intravenous anaesthesia.MethodsProspective observational study. Patients undergoing elective open infrarenal abdominal aortic aneurysm repair received balanced (desflurane + remifentanil, n = 20) or total intravenous anaesthesia (TIVA, propofol + remifentanil using target-controlled infusion, n = 20) according to the clinician’s decision. A goal-directed haemodynamic management was applied in all patients. Measurements were obtained before anaesthesia induction (baseline) and at end-surgery and included haemodynamics, arterial/venous blood gases, sublingual microvascular flow and density (incident dark field illumination imaging), peripheral muscle tissue oxygenation and microcirculatory reactivity (thenar near infrared spectroscopy with a vascular occlusion test).ResultsThe two groups did not differ for baseline characteristics, mean aortic-clamping time and requirement of vasoactive agents during surgery. Changes in mean arterial pressure, systemic vascular resistance index, haemoglobin and blood lactate levels were similar between the two groups, while the cardiac index increased at end-surgery in patients undergoing balanced anaesthesia. The sublingual microcirculation was globally unaltered in the TIVA group at end-surgery, while patients undergoing balanced anaesthesia showed an increase in the total and perfused small vessel densities (from 16.6 ± 4.2 to 19.1 ± 5.4 mm/mm2, p < 0.05). Changes in microvascular density were negatively correlated with changes in the systemic vascular resistance index. The area of reactive hyperaemia during the VOT increased in the balanced anaesthesia group (from 14.8 ± 8.1 to 25.6 ± 14.8%*min, p < 0.05). At end-surgery, the tissue haemoglobin index in the TIVA group was lower than that in the balanced anaesthesia group.ConclusionsIn patients undergoing elective open abdominal aortic aneurysm repair with a goal-directed hemodynamic management, indices of sublingual or peripheral microvascular perfusion/oxygenation were globally preserved with both balanced anaesthesia and TIVA. Patients undergoing balanced anaesthesia showed microvascular recruitment at end-surgery.Trial registrationNCT03510793, https://www.clinicaltrials.gov, date of registration April 27th 2018, retrospectively registered.
Our aim in this observational, prospective, noncontrolled study was to detect, in 29 patients who underwent abdominal aortic aneurysm (AAA) surgery, correlations between the incidence of postoperative organ failure and intraoperative changes in arterial and portal blood lactate; changes in intramucosal sigmoid pH (pHi); differences between sigmoid Pco(2) and arterial Pco(2) (DeltaCO(2)); and hemoglobin (Hb). Hb, arterial blood lactate concentrations, pHi, and DeltaCO(2) (air tonometry) were recorded at the start of anesthesia (T0), before aorta clamping (T1), 30 minutes after clamping (T2), and at the end of surgery (T3). Portal venous lactate concentrations were recorded at T1 and T2. Patients were stratified into two groups: group A patients had no postoperative organ failure, and group B patients had one or more organ failures. As compared with group A (n = 16), group B patients (n = 13) had a lower pHi value at T2 and T3 and a higher DeltaCO(2) at T3. A pHi value of <7.15 was a predictor of organ failure, with a sensitivity of 92.3%, a specificity of 68.8%, and positive and negative predictive values of 70.6% and 91.7%, respectively, whereas a DeltaCO(2) value of >28 mm Hg predicted later organ failure with a sensitivity of 92.3%, a specificity of 62.5%, and positive and negative predictive values of 66.6% and 90.9%, respectively. Portal venous lactate concentrations were larger in group B at T2 (P < 0.001), and an increase >or=5 g/dL predicted later postoperative organ failure with a sensitivity of 92.3%, a specificity of 100%, and positive and negative predictive values of 100% and 94.1%, respectively. The comparison of the receiving operator characteristic curves to test the discrimination of each variable and the logistic regression analysis revealed that the increase in portal lactate was the best predictor for the development of postoperative organ failure. Hb concentration was significantly smaller in group B at T0 (13.8 +/- 1.0 g/dL versus 12.2 +/- 2.2 g/dL) and T2 (10.9 +/- 1.2 g/dL versus 9.1 +/- 1.9 g/dL). In conclusion, both pHi and DeltaCO(2) are reasonably sensitive prognostic indices of organ failures after AAA surgery, but they are less specific and accurate than portal venous lactate.
Serum cortisol level and depth of propofol-induced sedationSir, Recently, it was demonstrated that preoperative anxiety modified the amount of propofol required for induction and maintenance of anesthesia (1). Another study similarly suggested that increased anxiety before surgery was associated with increased intraoperative anesthetic requirements (2). Anxiety is known to elicit physiological stress responses, including an elevation of the serum cortisol level. Cortisol has been found to modulate the central nerve system (3), and an increase in neuronal activity by the iontophoretic application of cortisol was demonstrated in rat brain (4). It can be hypothesized that cortisol response modulates an anesthetic effect and depth of sedation with intravenous anesthetic. Thus, we investigated the relationship between the serum cortisol level and the depth of propofolinduced sedation.After local Ethics Committee approval, we studied 11 healthy male volunteers aged 26-39 years taking no chronic medications, for whom written informed consent was obtained. To avoid possible diurnal variations in the serum cortisol level, all studies started at 09.30 hours. Following a rest of 20 min, propofol was administered at a rate of 6 mg.kg À1 .h À1 for the initial 5 min, then maintained at a rate of 3 mg.kg À1 .h À1 . Venous blood samples for the measurement of serum cortisol and propofol were obtained before propofol infusion (baseline) and at 30, 60, and 90 min after the start of infusion. Depth of sedation was assessed using the Ramsay scale and the bispectral index (BIS) value obtained with a BIS monitor (model A-1050, Aspect Medical Systems, Inc., Newton, MA) immediately before blood collection. Serum cortisol and propofol were measured using an enzyme-linked immunosorbent assay and high-performance liquid chromatography, respectively. Statistical analyses of changes in each variable over time were performed by repeated-measures ANOVA, followed by the Bonferroni t-test, and the relationship between the variables by analysis of linear regression or Kendall's rank correlation coefficients. Significant difference was defined as P < 0.05.Bispectral index values and serum cortisol levels significantly decreased at 30, 60, and 90 min after the start of propofol infusion in a similar pattern. Ramsay scales during sedation varied among the subjects and ranged between 2 and 5, increasing significantly after the propofol administration. The depth of sedation indicated by the Ramsay scale and the BIS value was significantly related to the serum cortisol level and blood propofol concentration. However, there was no relationship between the serum cortisol level and the blood propofol concentration. Furthermore, the serum cortisol level at baseline was significantly related to the Ramsay scales and the BIS values at 30 and 60 min after the start of propofol infusion. A subject with a low baseline serum cortisol level had a tendency to experience deeper sedation than a subject with a higher level. In particular, a strong relationship betwee...
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P14 Facial continuous positive airway pressure therapy for cardiogenic pulmonary oedema: a study of its efficacy in an emergency department setting within the UK
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