Jean Paul Viale

Effects of a continuous low-dose clonidine epidural regimen on pain, satisfaction and adverse events during labour: a randomized, double-blind, placebo-controlled trial.

Background and objective Epidural clonidine has been proposed as an adjunct for anaesthetic mixtures during labour. Administered as a bolus, clonidine may have side effects such as sedation and hypotension; its continuous infusion could be attractive in this respect. We, therefore, conducted a randomized, double-blind trial using patient-controlled epidural analgesia with a background infusion using a low dose of clonidine during labour. Methods A total of 128 healthy parturients in active labour received a patient-controlled epidural analgesia solution of 0.0625% levobupivacaine and sufentanil 0.25 μg ml−1 with or without clonidine 2 μg ml−1. Ninety-five parturients were analysed. The pain score over time was evaluated as well as drug volume utilization; supplementation bolus and side effects were recorded. The primary endpoint was maternal satisfaction [ClinicalTrials.gov Identifier (NCT00437996)]. Results Three patients in the control group failed to achieve satisfactory epidural analgesia owing to a technical issue. Although the primary endpoint was not statistically significant, analgesia was more pronounced and obtained earlier in the clonidine group. The area under the curve for the visual analogue pain score was significantly lower in the clonidine group. In this group, hourly doses of levobupivacaine and sufentanil were reduced (13.9 ± 4.3 vs. 16.3 ml ± 4.0; P = 0.005) as well as rescue supplementation and pruritus incidence (18 vs. 46%; P = 0.004). Maternal blood pressure was significantly lower, over time, in the clonidine group but remained within the normal range. Sedation was similar in both groups (4.3 vs. 2.0%; not significant). Conclusion The addition of clonidine to epidural levobupivacaine and sufentanil for patient-controlled epidural analgesia in labour improved analgesia, reduced the supplementation rate and reduced pruritus without improvement in maternal satisfaction. Blood pressure was significantly lower in the clonidine group over time but without clinical consequence.

Comparison between Respiratory Variations in Pulse Oximetry Plethysmographic Waveform Amplitude and Arterial Pulse Pressure during Major Abdominal Surgery

Background:To assess preload dependence, the variation of the plethysmographic waveform of pulse oximetry (&Dgr;POP) has been proposed as a surrogate of the pulse pressure variation (&Dgr;PP). The aim of the study was to assess the ability of the pulse oximeter–derived plethysmographic analysis to accurately trend &Dgr;PP in patients undergoing major abdominal surgery by using standard monitors. Methods:A continuous recording of arterial and plethysmographic waveform was performed in 43 patients undergoing abdominal surgery. &Dgr;PP and &Dgr;POP were calculated on validated respiratory cycles. Results:For analysis, 92,467 respiratory cycles were kept (73.5% of cycles recorded in 40 patients). The mean of intrapatient coefficients of correlation was low (r = 0.22). The Bland and Altman analysis showed a systematic bias of 5.21; the &Dgr;POP being greater than the &Dgr;PP, this bias increased with the mean value of the two indices and the limits of agreement were wide (upper 21.7% and lower −11.3%). Considering a &Dgr;PP threshold at 12% to classify respiratory cycles as responders and nonresponders, the corresponding best cutoff value of &Dgr;POP was 13.6 ± 4.3%. Using these threshold values, the observed classification agreement was moderate (&kgr; = 0.50 ± 0.09). Conclusions:The wide limits of agreement between &Dgr;PP and &Dgr;POP and the weak correlation between both values cast doubt regarding the ability of &Dgr;POP to substitute &Dgr;PP to follow trend in preload dependence and classify respiratory cycles as responders or nonresponders using standard monitor during anesthesia for major abdominal surgery.

Factors associated with noninvasive ventilation failure in postoperative acute respiratory insufficiency: an observational study.

Background and objective Few data are available on the efficacy of noninvasive ventilation (NIV) in postoperative patients with acute respiratory failure (ARF). Methods Seventy-two patients coming from the surgical wards with postoperative ARF were retrospectively evaluated. The major characteristics of patients who were intubated were compared with the characteristics of those who were not after a trial of NIV. Predictive factors for failure of NIV were analysed. Results Out of 72 patients with ARF after surgery who were treated with NIV, 42 avoided intubation (58%). On a univariate analysis, a decrease in the paO2/FiO2 ratio after 1 h of NIV (223 ± 84 to 160 ± 68 mmHg, P < 0.05) was associated with NIV failure and need for tracheal intubation because of nosocomial pneumonia and an increased simplified acute physiology score (SAPS) 2. In a multivariate analysis, nosocomial pneumonia [odds ratio (OR) 4.189; 95% confidence interval (CI) 1.383–12.687] and SAPS 2 higher than 35 (OR 4.969; 95% CI 1.627–15.172) were independent predictive factors of NIV failure. NIV success was associated with a reduced ICU stay (16.8 vs. 26.1 days, P < 0.001). Conclusion NIV could be considered in postoperative patients who presented with ARF. Nosocomial pneumonia is predictive of NIV failure.

Hepatic ischemia is associated with an increase in liver parenchyma nitric oxide that is in part enzyme-independent.

Background Nitric oxide (NO) might be involved in liver response to local ischemia–reperfusion injury. Methods A specific NO-sensitive electrode was inserted into liver parenchyma of anesthetized rabbits. After a 45-min period of stable NO signal, the vascular pedicle of the caudal lobe of the liver was clamped for 45 min, then the clamp was removed. Perfusion of the right upper lobe was left unchanged. The same procedure was applied in other animals after administration of a long-acting nonspecific NO synthase inhibitor NAPNA. Results Occlusion of the caudal pedicle was associated with a mean threefold increase in NO signal measured in the caudal lobe. After unclamping, this signal returned within 8 min to baseline value and remained stable for the next 6 h. In the right upper lobe, NO signal was unaffected by caudal lobe ischemia. By the end of the 6-h reperfusion period, administration of the NO inhibitor l-NAME led to a suppression of the NO signal, thus demonstrating the specificity of the measurement. Plasma nitrate and nitrite concentrations remained almost unchanged during the study period in all groups. In animals whose NO synthases had been previously inhibited by NAPNA, clamping the caudal pedicle for 45 min was still associated with a significant increase in caudal lobe NO signal. Conclusion Nitric oxide is present in liver parenchyma, and its generation is dramatically affected by an ischemia injury. The increased NO generation during local ischemia is, at least in part, independent of NO synthases.

Amounts of Bile Acids and Bilirubin Removed During Single‐Pass Albumin Dialysis in Patients With Liver Failure

To the Editor, In severe liver failure the accumulation of several toxins including bilirubin and bile acids has been blamed to account for distant organ dysfunctions (1) and of further liver impairment (2). Accordingly, extracorporeal dialysis has long been proposed in liver failure, as a symptomatic treatment to remove toxins from the patient. The purpose is to provide a bridge, either to liver transplantation, or hepatic regeneration. As the toxins accumulated in liver failure are mainly bound to albumin, adding albumin in the dialysate has been shown to enhance the clearance rate of those toxins. To date, two albumin dialysis systems have been developed, using a dialysate in a closed circuit which regenerates the albumin (3). They require special training and expertise and a specific circuit involving sorbent columns. Effective albumin dialysis can be performed by using a conventional continuous venovenous hemodialyzer, but with a dialysate being enriched with albumin. This system, called single pass albumin dialysis (SPAD), has been initially described in clinical use by Seige et al. in 1999 and also uses the bound-solute dialysis principle but in a more simple and less expansive design (4). It can be performed on any standard hemodialyzer with a high-flux dialyzing polysulfone membrane and a standard dialyzing solution enriched with human albumin. Although in vitro studies confirmed the feasibility of such albumin dialysis (5) clinical studies report case reports (6) or more recently short cohorts of patients (7–9). In this study, our purpose was to measure the plasmatic decrease in total bilirubin and bile acids induced by SPAD session in 14 patients and to evaluate its correlation with the actual extracted amount. We performed a retrospective analysis of 14 consecutive patients treated with SPAD for acute liver failure (ALF-n = 2) or acute on chronic liver failure (AoCLF-n = 12). All patients were informed of the procedure, and as a retrospective observational study any Institutional Review Board approval was not searched for. The first three sessions were analyzed when carried out (n = 37). Beside the albumin dialysis, all patients received standard medical therapy for liver failure, including, when necessary, N-acetyl cysteine, anti-oxidant vitamins, terlipressin or norepinephrine in case of hepatorenal syndrome, 40 mg per day of solumedrol in case of proved alcoholic hepatitis, and systemic antibiotics in case of sepsis. Indications for SPAD were stage II or more hepatic encephalopathy and/or a total blood bilirubin level of at least 300 mmol/L. SPAD was conducted with a conventional venovenous hemodialyzer without ultrafiltration (HOSPAL Gambro, Lund, Sweden). The blood flow and dialysate rates were 150 mL/min and 1000 mL/h, respectively. Dialysate solutions were prepared to obtain a final concentration of 3.2% albumin. Each treatment lasted 10 h corresponding to 10 L of albumin dialysis. Measurement of toxins in the serum and in the effluent dialysate allowed us to calculate clearances rates and extracted amounts. Six patients were listed for liver transplantation, and were eventually transplanted after 3, 4, 5, 21, 22, and 45 days of treatment.A transplanted patient died 34 days after transplantation from Escherichia coli septicemia. Only two patients, suffering from acute alcoholic hepatitis and toxic hepatitis, survived without transplantation. They were discharged from the intensive care unit (ICU) at 16 and 63 days, after six and one SPAD sessions, respectively. Ammonia levels were not modified by the SPAD sessions, whereas changes in urea and creatinine plasmatic levels, although significant were tenuous (Table 1). The prothrombin ratio, factor V and fibrinogen levels were not modified by SPAD sessions. Conversely, platelet levels decreased slightly but significantly from 64 (34–118) g/L before SPAD to 58 (32–104) g/L after SPAD (median [1–3 quartile]). Total serum bilirubin and bile acids levels decreased significantly after each SPAD session of 19 (11–24) % and 33 (24–45) % from the initial values, respectively. The plasma clearance rates were 4.0 (2.0–5.0) mL/min and 14.2 (9.4–18.5) mL/min for the total bilirubin and bile acids, respectively. The total extracted amounts Therapeutic Apheresis and Dialysis 15(5):504–510 doi: 10.1111/j.1744-9987.2011.00980,00977,00978,00975.x