Cardiac output monitoring with thermodilution pulse-contour analysis vs. non-invasive pulse-contour analysis.

Intravenous fluid boluses guided by changes in stroke volume improve some outcomes after major surgery, but invasive measurments may limit use. From October 2016 to May 2018, we compared the agreement and trending ability of a photoplethysmographic device (Clearsight) with a PiCCO, calibrated by thermodilution, for haemodynamic variables in 20 adults undergoing major elective surgery. We analysed 4519 measurement pairs, including before and after 68 boluses of 250 ml crystalloid. The bias and precision of stroke volume measurement by Clearsight were -0.89 ± 4.78 ml compared with the invasive pulse-contour cardiac output device. The coefficient of agreement for stroke volume variation after fluid boluses between the two devices was 0.79 ('strong'). Fluid boluses that increased stroke volume by ≥ 10% increased mean absolute volume (SD) and mean percentage (SD) stroke volume measurements similarly for the invasive pulse-contour cardiac output and Clearsight devices: 9 (4) ml vs. 8 (4) ml and 16% (8%) vs. 15% (10%), respectively, p > 0.05. The non-invasive Clearsight pulse-contour analysis was similar to an invasive pulse-contour device in measuring absolute and changing stroke volumes during major surgery.

Percutaneous microwave ablation of renal cancers under CT guidance: safety and efficacy with a 2-year follow-up.

AIM: To evaluate the safety and efficiency of percutaneous microwave ablation (MWA) of renal cell carcinomas (RCC) carried out under computed tomography (CT) guidance. MATERIALS AND METHODS: A retrospective study was performed on RCC that was either histologically proven or diagnosed at imaging (Bosniak IV cyst) and treated by MWA under general anaesthesia with CT guidance. Indications for percutaneous ablation were based on the American Urological Association recommendations. Twenty-four months post-procedure follow-up was performed. RESULTS: Sixty-two patients presenting one or more RCC (84 tumours ranging from 10-48 mm in diameter; mean diameter: 25.6 mm) were included. Technical success was achieved for 78 tumours (58 patients). For four patients, the treatment was stopped due to gas dissection failure. At 3 months, six residual tumours were observed (8%). At 6 months, two recurrences and one residual tumour (3.8%) were observed; all were retreated with complete success. At 12 months, local control of the disease was achieved in 94% of cases (100% in cases where treatment was performed). Two cases of distal metastasis were observed after 12 and 24 months. At 24 months, one patient presented with a contralateral tumour. The complication rate was 4.8% including one grade III complication and two grade II complications according to the Clavien-Dindo classification. At 2 years, the cumulative disease-free survival rate and overall survival were 95% and 97%, respectively. CONCLUSION: MWA ablation under CT guidance to treat RCC is safe and provides a high rate of effectiveness at 24 months.

Appropriate dosing of sugammadex to reverse deep rocuronium-induced neuromuscular blockade in morbidly obese patients.

In morbidly obese patients, the speed of reversal of neuromuscular blockade with sugammadex based on ideal body weight is still matter of debate. In this single-center, randomised, double-blinded study, neuromuscular blockade was monitored in 50 patients using acceleromyography at the adductor pollicis. At the end of surgery with deep rocuronium-induced neuromuscular blockade, patients randomly received sugammadex 4 mg.kg(-1) (high dose group), 2 mg.kg(-1) (middle dose group), or 1 mg.kg(-1) (low dose group) of ideal body weight. After administration of the first dose of sugammadex, the mean (SD) recovery time (censored at 600 s) from deep neuromuscular blockade was significantly shorter (p < 0.001) in the high-dose group (n = 14; 255 (63) s) vs the middle-dose group (n = 13; 429 (102) s), or low-dose group (n = 4; 581 (154) s). Success rate from neuromuscular blockade reversal defined by a train-of-four ≥ 0.9 within 10 min after sugammadex administration, were 93%, 77% and 22% for these high, middle and low-dose groups respectively (p < 0.05 vs low-dose group). In morbidly obese patients, 4 mg.kg(-1) of ideal body weight of sugammadex allows suitable reversal of deep rocuronium-induced neuromuscular blockade. Monitoring remains essential to detect residual curarisation or recurarisation.

Continuous monitoring of haemoglobin concentration after in-vivo adjustment in patients undergoing surgery with blood loss.

Non-invasive monitoring of haemoglobin concentration provides real-time measurement of haemoglobin concentration (SpHb) using multi-wavelength pulse co-oximetry. We hypothesised that in-vivo adjustment using the mean of three haemoglobinometer (HemoCue®) measurements from an arterial blood sample at the first SpHb measurement (HCueART) would increase the accuracy of the monitor. The study included 41 adults for a total of 173 measurements of haemoglobin concentration. In-vivo adjusted SpHb was automatically calculated by the following formula: in-vivo adjusted SpHb = unadjusted SpHb - (SpHb - HCueART). The accuracy of in-vivo adjusted SpHb was compared with SpHb retrospectively adjusted using the same formula, except for haemoglobin level which was assessed at the central laboratory and then compared with all other available invasive methods of haemoglobin measurement (co-oximetry, HbSAT; arterial HemoCue, HCueART; capillary HemoCue, HCueCAP). Compared with laboratory measurement of haemoglobin concentration, bias (precision) for unadjusted SpHb, in-vivo adjusted SpHb, retrospectively adjusted SpHb, HbSAT, HCueART and HCueCAP were -0.4 (1.4), -0.3 (1.1), -0.3 (1.1), -0.6 (0.7), 0.0 (0.4) and -0.5 (1.2) g.dl(-1) , respectively. In-vivo adjustment of SpHb values using the mean of three arterial HemoCue measurements improved the accuracy of the device similar to those observed after a retrospective adjustment using central laboratory haemoglobin level.

An in vitro evaluation of infusion methods using a syringe pump to improve noradrenaline administration.

BACKGROUND: International guidelines recommend noradrenaline (NA) as the vasopressor of choice to treat septic shock. The aim of this study was to determine the best way to infuse patients with NA. METHODS: The in vitro study was designed to measure NA concentration at the end of each studied assembly line. Three infusion systems used the double pump method and three single pumps, which differed as regards NA concentrations (0,2 - 0,5 - 1 mg/h), dead space volume of the devices and the use of saline. Infusion systems were compared according to the time necessary to reach an NA mass flow rate steady-state plateau after the onset of infusion or after a flow change. RESULTS: Times were significantly different between the six methods for infusing NA. The system using the double syringe method with a standard extension set was the longest to reach the steady state after the onset of infusion [40.00 min (19.57 - 49.22)]. The steady-state plateau was obtained most rapidly with the double-syringe pump systems using very low dead-space volume extension sets and single-syringe pump systems containing diluted noradrenaline at the beginning of NA infusion. CONCLUSION: A combination of a low dead-space volume extension set and a double pump method with a constant saline flow rate at 5 ml/h might be the solution to provide the most reliable NA infusion delivery.

Comparison of acoustic and impedance methods with mask capnometry to assess respiration rate in obese patients recovering from general anaesthesia.

Respiratory depression, a potentially serious complication after general anaesthesia, can be detected promptly by close monitoring of both oxygen saturation and respiratory rate. Obese patients have morphological changes that may impair the reliability of monitoring devices. In this study, respiration rate was simultaneously recorded every second for up to 60 min using a computer in 30 adult obese patients (body mass index ≥ 35 kg.m(-2)), by three methods: acoustic; thoracic impedance; and capnometry via a facemask (Capnomask, reference method). Of the 99,771 data triplets collected, only 85,520 (86%) were included; 12,021 (84%) were not studied due to failure of capnometry and 2240 (16%) due to failure of the acoustic method. Compared with capnometry, bias was similar using both the acoustic method and impedance (-0.3 bpm vs. -0.6 bpm, respectively, p = 0.09), but limits of agreement were narrower for the acoustic method (±3.5 bpm vs. ±5.3 bpm, respectively, p = 0.0008). The proportion of respiration rate values obtained with the acoustic method and impedance that differed by at least 10% or 20% for more than 15 s were 11% vs. 23% and 2% vs. 6%, respectively (p = 0.0009 for both comparisons). The acoustic sensor was well tolerated, while the facemask was pulled off on several occasions by four (13%) agitated patients. In obese patients requiring close monitoring of respiration rate, the acoustic method may be more precise than thoracic impedance and better tolerated than capnometry with a facemask.

[Process, procedure and requested conditions for academic appointment in anesthesia and intensive care]. / Processus, procédures et critères d'évaluation conduisant à la mise sur la liste d'aptitude aux fonctions de Maître de conférences des universités--praticien hospitalier (MCU-PH) et de professeur des universités--praticien hospitalier (PU-PH) en anesthésie-réanimation.

Since several decades, anesthesia care and intensive care, as well, are engaged in the way of excellence in clinical care and research. This requirement is also applied for the selection of professor and academic workers. The goals of this article are twice: first to diffuse this knowledge at the medical community and second to describe in details the long process leading to the final appointment.

Impact of infusion set characteristics on the accuracy of patient-controlled morphine administration: a controlled in-vitro study.

The aim of our in-vitro study was to assess the impact of infusion set characteristics on the accuracy of morphine doses in patient-controlled analgesia. Two infusion sets differing in conception and dead-space volume were assessed: a standard set and a low dead-space volume Y-set. The patient-controlled analgesia programme parameters were as follows: bolus equal to 1 ml at 100 ml.h(-1) ; lockout intervals equal to 5 and 10 min; and carrier fluid flow rate equal to 10 and 50 ml.h(-1) . Morphine concentration was determined by an ultraviolet spectrophotometric method. The morphine doses were significantly different from one set to the other during bolus and lockout intervals, whatever the patient-controlled analgesia programme. The average doses were approximately 1.3-6.0 times higher with the low dead-space volume Y-set during bolus. Our study underlines the impact of infusion set characteristics on the accuracy of morphine patient-controlled analgesia doses.

[Regional survey of peripheral nerve block practice by French residents]. / Pratique de l'anesthésie locorégionale périphérique par les internes en anesthésie-réanimation en région Poitou-Charentes.

OBJECTIVES: There are limited data on peripheral nerve block (PNB) practices by residents in France, especially with after introduction of ultrasound. A survey was conducted on PNB practices by French residents. STUDY DESIGN: Multicenter prospective descriptive study. PATIENTS AND METHODS: All residents completed a survey form after each PNB procedure. RESULTS: A total of 394 procedures performed by 21 residents in 4 hospitals were collected. The number of procedures and average volume of local anesthetics by type of block are: axillary block 245-25mL (62%), interscalene 29-21mL (7%), supraclavicular 1-25mL (0.3%), 2-25mL infraclavicular (0.5%), femoral 65-18mL (16.5%), sciatic 52-22mL (13%). Detection was done by ultrasound only for 365 (92.6%) procedures, and neurostimulation only for 23 (5.8%) procedures. The duration of procedure was less than 5min for 200 (50.7%) procedures and more than 15min for 16 (4%) procedures. A single puncture was required for 307 (78%) procedures. The initial block success was obtained in 369 (93%) procedures. High training level residents required less time (P<0.0001), less puncture (P<0.046) and less neurostimulation use (P<0.0001) than novices, without difference in success rate and the volume of local anesthetic required. CONCLUSIONS: The majority of procedures performed by the residents are using ultrasound. The procedure is usually fast, requiring mainly a single puncture and has a high rate of success.

Prevention of drug delivery disturbances during continuous intravenous infusion: an in vitro study on a new multi-lumen infusion access device.

OBJECTIVE: Stopping and restarting carrier fluid flow and performing simultaneous drug infusions can lead to hazardous disturbances in drug delivery. The present study was designed to assess in vitro whether using a multi-lumen infusion access device could prevent noradrenaline disturbances. STUDY DESIGN: In vitro laboratory work. METHODS: Two infusion devices were studied: a standard device with a four-port manifold and a 150cm extension line and a nine-lumen infusion device (Edelvaiss-Multiline(®)) with eight accesses connected to nine separate lumens in a single tube of 150cm: seven accesses connected to seven peripheral lumens and one for the carrier fluid access connected to two lumens. Two experimental protocols of noradrenaline infusion were made: (a) drug flow rate change and (b) stop-and-go carrier fluid flows. Two parameters were studied: drug mass flow rate and flow change efficiency (FCE) calculated from the ratio of the area under the experimental mass flow rate curve to the area under the theoretical instantaneous mass flow rate curve. RESULTS: Variations in noradrenaline mass flow rate were more rapid with the Edelvaiss-Multiline(®) when the noradrenaline infusion rate was increased or decreased. FCE was significantly different from one infusion device to the other during both noradrenaline flow rate increase (standard vs. nine-lumen: 58% vs. 84%; P=0.008) and decrease (175% vs. 108%; P=0.008). Decreased drug delivery after stopping carrier fluid flow (standard vs. nine-lumen: 21% vs. 98%; P=0.008) and sudden temporary increases on resumption (253% vs. 103%; P=0.008) were reduced in magnitude and duration when using the Edelvaiss-Multiline(®) with a significant difference in FCE between the two infusion devices. CONCLUSIONS: Using the nine-lumen infusion device reduces drug delivery disturbances during continuous intravenous infusion.

Comparison of haemoglobin measurement methods in the operating theatre.

BACKGROUND: Various methods of haemoglobin (Hb) measurement are available to guide transfusion including several methods that allow for measurement at the bedside. This study directly compared their absolute and trend accuracy compared with values from the central lab (reference method). METHODS: Adult patients undergoing surgery with expected blood loss wore a rainbow ReSposable sensor connected to a Radical-7 Pulse CO-Oximeter (SpHb). Arterial samples were analysed with a haematology analyser (HbLab), a satellite CO-Oximeter (HbSat), and a point-of-care haemoglobinometer (HemoCue; HcueArt). Concomitantly, ear capillary blood was tested using the same haemoglobinometer (HcueCap). Absolute accuracy and the clinical significance of error were assessed with Bland-Altman plots and three-zone error grids. Trend analysis was performed using a modified polar plot, testing both directionality and magnitude of Hb changes compared with the reference. RESULTS: Two hundred and nineteen measurements from 53 patients with HbLab ranging between 6.8 and 16.3 g dl(-1) (4.2 and 10.1 mmol litre(-1)) were recorded. Compared with the reference method, bias (precision) was 0.2 (0.2) g dl(-1) [0.1 (0.1) mmol litre(-1)] for HcueArt, 0.8 (0.3) g dl(-1) [0.5 (0.2) mmol litre(-1)] for HbSat, 0.5 (0.5) g dl(-1) [0.3 (0.3) mmol litre(-1)] for HcueCap and 1.0 (1.2) g dl(-1) [0.6 (0.7) mmol litre(-1)] for SpHb. None of the devices tested would have led to unnecessary or delayed transfusion according to 2006 ASA transfusion criteria. Trend accuracy was better for HcueArt and HbSat than for HcueCap and SpHb. CONCLUSION: Bedside Hb measurement methods differ in their agreement to a laboratory haematology analyser but none would have led to transfusion errors. Trial Registry Number RCB 2009-AO1144-53.

[Management of infection risk in asplenic patients]. / Gestion du risque infectieux chez le splénectomisé

Each year in France 6000 to 9000 patients are splenectomised or spleen embolized. As spleen has immunological functions, it contributes to protect against infections. Thus, hypo or asplenia increase the risk of infection, especially the risk of Overwhelming Post-Splenectomy Infection (OPSI). OPSI is a medical emergency, characterized by aspecific symptoms, which may rapidly progress to fulminant infection and death in 50% of cases within 48 h. Encapsulated bacteria as Streptococcus pneumoniae, Haemophilus influenzae and Neisseria meningitidis are most of the time responsible of these infections in asplenic patients. To prevent OPSI, several measures are essential and must begin before a scheduled surgery or just after an urgent splenectomy. Patients must carry a card. The first proposed prevention measure is to enhance partial surgery when it's possible. Then, the two other measures, antibiotic prophylaxis and vaccination, shall be implemented whatever is the indication of surgery. Postoperative antibiotic prophylaxis by phenoxymethyl-penicillin is prescribed for two years minimum and lifelong prophylaxis should be offered to high risk of pneumococcal infection patients. Pneumococcal, H. influenzae type b and meningococcal vaccination should be administered 2 to 6 weeks before scheduled splenectomy and 2 weeks after urgent surgery. Yearly, patients must receive Influenza vaccination. As an interindividual variation exists in vaccinal response, measurement of serotype-specific antibodies can be used, if available, to individualized risk patients and to organize revaccination. Finally, to prevent OPSI, patient and next-of-kin must be educated about prevention measures and infectious risk to optimize patient's compliance.

[Simplified anesthesia protocol for cataract surgery under topical anesthesia: one year retrospective study]. / Protocole simplifié de prise en charge anesthésique chez les patients opérés de cataracte sous topique : étude rétrospective sur un an.

INTRODUCTION: The reduced supply of anesthesiologists in the hospital setting calls for a reconsideration of anesthesia management for ophthalmology patients. Therefore, a simplified management protocol has been designed through close collaboration between the involved specialists for cataract surgery under topical anesthesia (anesthetic eye drops or sub-Tenon's injection). MATERIALS AND METHODS: At the conclusion of the visit confirming the need for surgery, the surgeon completes a questionnaire designed to elicit a history of the presence of diabetes mellitus (type I or II), prior organ transplantation, chronic renal insufficiency requiring dialysis, communication difficulties, psychiatric disorders, allergy and/or a complex cataract. If one of the items is positive, the patient is scheduled for a preoperative anesthesia consult. If all the items are negative, this anesthesia evaluation is waived. The surgeon explains the fasting requirement and how to take the patient's usual medications on the morning of surgery. The patient continues his/her medications. No lab tests or chest X-ray are performed. If necessary, the surgeon prescribes preoperative antibiotic prophylaxis and any other preparation. During the surgery, the patient receives IV fluids and is monitored via EKG, non-invasive blood pressure and pulse oxymetry by a certified nurse anesthetist. The anesthesiologist on duty (one per every four rooms) is immediately available for the slightest problem. The surgeon signs the postoperative anesthesia note and discharge order. RESULTS: This procedure was assessed by one surgeon over a one year period, including 145 patients (60% of the patients recruited for this surgery), primarily outpatient (77%) under topical anesthesia (Oxybuprocaine(®)+Visthesia(®), Zeiss) or under sub-Tenon's injection (Xylocaïne(®)). No major complications were observed. Seven cases of arterial hypertension, treated with calcium channel blockers (nicardipine), and three episodes of brief anxiety were observed. CONCLUSION: This simplified anesthesia protocol appears to be safe and effective but requires more demanding involvement of the surgeon, whose scope of competence and responsibility must naturally increase. This is the only way by which cataract surgery can remain competitive.

[Inhaled agents in neuroanaesthesia for intracranial surgery: pro or con]. / Pour ou contre les halogénés en neuroanesthésie pour chirurgie intracrânienne.

Isoflurane, desflurane and sevoflurane all preserve cerebrovascular carbone dioxide (CO(2)) reactivity. They are all concentration-dependant cerebral vasodilatators and decrease cerebral metabolism. Sevoflurane induces the smallest cerebral vasodilatation and preserve cerebral autoregulation up to 1.5CAM, compared to isoflurane and desflurane which impair it upon 1CAM. Propofol has been compared to inhaled agents. Propofol preserve cerebrovascular CO(2) reactivity, blood flow-metabolism coupling, cerebral autoregulation and has no vasodilatation effect. None of the three inhaled agents induce any clinical relevant increase of intracranial pressure (ICP), but studies were conducted in patients without any intracranial hypertension (ICHT). However, compared to propofol, ICP and brain swelling were higher with inhaled agents, more with isoflurane compared to sevoflurane. Finally, neuroprotective properties have been described in experimental model for all the inhaled agents but clinical proofs are still lacking. In conclusion, for intracranial surgery without any ICHT inhaled agents can be used as a maintenance anesthetic with a preference for sevoflurane. In case of ICHT or a risk of ICHT during the surgery, propofol is preferred for it slightest effect on ICP and cerebral hemodynamic.

Accuracy of respiratory rate monitoring using a non-invasive acoustic method after general anaesthesia.

BACKGROUND: Respiratory rate should be monitored continuously in the post-anaesthesia care unit (PACU) to avoid any delay in the detection of respiratory depression. Capnometry is the standard of care but in extubated patients requires a nasal cannula or a face mask that may be poorly tolerated or can be dislodged, leading to errors in data acquisition and false alarms. The value of a new non-invasive acoustic monitor in this setting has not been fully investigated. METHODS: Adult patients admitted to the PACU after general anaesthesia were included. After tracheal extubation, an adhesive sensor with an integrated acoustic transducer (RRa™) was placed on the patient's throat and connected to its monitor while the patient breathed through a face mask with a carbon dioxide sampling port (Capnomask™) connected to a capnometer. Both the acoustic monitor and the capnometer were connected to a computer to record one pair of data per second for up to 60 min. RESULTS: Fifty-two patients, mean (range) age 54 (22-84) yr and BMI 26 (19-39) kg m(-2), were studied. Compared with capnometry, the bias and limits of agreement of the acoustic method were 0 (-1.4-1.4) bpm. The acoustic sensor was well tolerated while the face mask was removed by eight patients, leading to study discontinuation in two patients. CONCLUSIONS: In extubated patients, continuous assessment of respiration rate with an acoustic monitor correlated well with capnometry.