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.

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.

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.

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.

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.

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.

Accuracy of respiratory rate monitoring by capnometry using the Capnomask(R) in extubated patients receiving supplemental oxygen after surgery.

BACKGROUND: Respiratory monitoring is standard after anaesthesia and surgery. Abnormal respiratory rate is a sensitive indicator of respiratory problems, even in patients receiving supplemental oxygen, but the best method for its continuous measurement in spontaneously breathing patients is unclear. This study compared respiratory rate assessment by capnometry using a new oxygen mask with a carbon dioxide sampling port (Capnomask(®)) and thoracic impedance pneumography with clinical measurement (used as a reference method) in extubated patients receiving supplemental oxygen. METHODS: Adult males admitted to the post-anaesthesia care unit after general anaesthesia were studied. Immediately after extubation, a Capnomask(®) connected to a capnometer was positioned appropriately. Respiratory rate was measured by visual inspection of chest movement for 1 min, by capnometry, and thoracic impedance pneumography. One set of measurements was obtained for every patient receiving supplemental oxygen at different flow rates. RESULTS: Twenty men, mean (inter-quartile range) age 54 (23-66) yr and BMI 25 (21-31) kg m(-2), were studied. Compared with visual inspection, the bias and limits of agreement were 0.0 (1.0 to -1.0) bpm for the Capnomask(®) and -2.2 (2.0 to -6.5) bpm for the impedance pneumography. The accuracy of respiratory rate assessment using Capnomask(®) was not influenced by the supplemental oxygen flow rate. CONCLUSIONS: In extubated patients, continuous assessment of respiratory rate with the Capnomask(®) is more accurate than by thoracic impedance pneumography even when supplemental oxygen is delivered at a high flow rate.

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.

Gabapentin premedication: assessment of preoperative anxiolysis and postoperative patient satisfaction.

BACKGROUND: Gabapentin reduces anxiety in psychiatric patients. In this prospective, randomized, double-blinded, placebo-controlled study, we investigated whether a single dose of gabapentin as a premedicant reduces preoperative anxiety, and improves patient satisfaction. MATERIALS AND METHODS: After Institutional Review Board approval and written consent, 210 patients were randomly allocated into 3 groups of oral premedication: placebo, hydroxyzine 75 mg, or gabapentin 1200 mg. Anxiety level was assessed 3 times, using a 100-mm visual analogue scale: before premedication, in the preoperative holding area, and just before induction of general anaesthesia. In the postoperative period, patients were asked about their satisfaction with their premedicant. Data were presented as mean +/- SD. VAS scores were analyzed by repeated-measures analysis of variance followed by a Bonferroni test as appropriate. The chi-square test was used to analyze categorical data. All p values less than 0.05 was considered statistically significant. RESULTS: Baseline anxiety was not statistically different among the 3 groups. Anxiety level in the gabapentin group was significantly lower in the holding area, and before induction of anaesthesia (20 mm +/- 21), than in the hydroxyzine group (33 mm +/- 26 ; p = 0.023) and in the placebo group (36 mm +/- 28; p = 0.004). Anxiety decreased significantly overtime only in the gabapentin group. The gabapentin and hydroxyzine groups had a higher proportion of "satisfied or extremely satisfied" patients (73% and 70% respectively) as compared to the placebo group (48%, p = 0.006). CONCLUSION: A single dose of gabapentin has proven to be an effective premedication to reduce preoperative anxiety.

Pharmacokinetics and pharmacodynamics of rocuronium at the vocal cords and the adductor pollicis in humans.

The pharmacokinetic-pharmacodynamic relationship of rocuronium at the laryngeal adductor muscles and the adductor pollicis was determined in eight patients during general anesthesia. Rocuronium was administered as an infusion at a rate of 100 micrograms.kg-1.min-1 over 5 minutes. The half-life of transport between plasma and biophase (effect compartment) was significantly shorter at the adductor laryngeal muscles (2.7 +/- 0.6 minutes, mean +/- SD) than at the adductor pollicis (4.4 +/- 1.5 minutes, p = 0.003). The concentration in the effect compartment producing 50% of the maximum effect was significantly greater at the adductor laryngeal muscles (1424 +/- 148 micrograms.L-1) than at the adductor pollicis (823 +/- 157 micrograms.L-1, p = 0.0001). The shorter onset of neuromuscular blockade at the laryngeal muscles than at the adductor pollicis may be explained by a faster transfer rate at the laryngeal adductor muscles neuromuscular junction than at the adductor pollicis neuromuscular junction.

Pharmacokinetics and pharmacodynamics of sequential intravenous and subcutaneous teicoplanin in critically ill patients without vasopressors.

OBJECTIVE: To compare the pharmacokinetic parameters of sequential intravenous and subcutaneous teicoplanin in the plasma of surgical intensive care unit patients. DESIGN AND SETTING: Prospective, randomized, crossover study in the surgical ICU of a university hospital. PATIENTS: Twelve patients with a suspected nosocomial infection, a serum albumin level higher than 10 g/l, body mass index less than 28 kg/m(2), and estimated creatinine clearance higher than 70 ml/min. INTERVENTIONS: Teicoplanin was first administered intravenously as a loading dose of 6 mg/kg per 12 h for 48 h and then continued at a daily dose of 6 mg/kg. On the fourth day patients were randomized in two groups according to the order of the pharmacokinetic studies. MEASUREMENTS AND RESULTS: Serial plasma samples were obtained to measure teicoplanin levels. Compared with a 30-min intravenous infusion the peak concentration of teicoplanin after a 30-min subcutaneous administration occurred later (median 7 h, range 5-18) and was lower (16 micro g/ml, 9-31; vs. 73, 53-106). Despite large and unpredictable interindividual differences no significant differences between subcutaneous and intravenous administration were observed in: trough antibiotic concentrations (10 micro g/ml, 6-24; vs. 9, 5-30), the area under the teicoplanin plasma concentration vs. time curves from 0 to 24 h (AUC(0-24h); 309 micro g/ml per minute, 180-640; vs. 369, 171-955), the proportion of the dosing interval during which the plasma teicoplanin concentration exceeded 10 micro g/ml (96%, 0-100%; vs. 79%, 13-100%), and the ratio of AUC(0-24h) to 10 (77, 45-160; vs. 92, 43-239). CONCLUSIONS: In critically ill patients without vasopressors a switch to the subcutaneous teicoplanin after an initial intravenous therapy seems to give comparable pharmacodynamic indexes of therapeutic success.

Treatment of peritoneal carcinomatosis by intraperitoneal chemo-hyperthermia: reliable and unreliable concepts.

Intraoperative peritoneal chemo-hyperthermia (IPCH) is a promising treatment of peritoneal carcinomatosis arising from digestive tumors. After presenting the rationale for the use of IPCH, this review reports the results published to date by different groups. Unfortunately, data with respect to technical aspects, indications and results are unclear, inhomogeneous and questionable. The discussion presents reliable and unreliable points, mainly concerning the technical aspects of IPCH: what is the maximal desirable tumor thickness before initiating treatment? What is the ideal temperature? Is central hyperthermia beneficial? What is the ideal duration? What is the most effective antimitotic drug? A new classification of peritoneal seeding before cytoreductive surgery and before the initiation of IPCH, is proposed, and a suggestion concerning the reporting of drug concentrations made. Numerous prospective studies need to be conducted to test different technical modalities and to evaluate the results of IPCH.

[Intraperitoneal hyperthermic chemotherapy (IPHC), a promising treatment of peritoneal carcinomatosis]. / La chimio-hyperthermie intrapéritonéale (CHIP), un traitement prometteur mais encore mal connu de la carcinose péritonéale.

Intraperitoneal hyperthermic chemotherapy (IPHC) appears to be a promising treatment of peritoneal carcinomatosis. This paper reports the physio-pathological background of IPHC and the various studies which have been published in the literature. It points out the heterogeneity of these series and discuss the most critical points as surgical indications, choice of the antineoplastic drugs, their doses, temperatures of the IPHC, extend of the cytoreductive surgery, morbidity and mortality. Finally, several options are proposed for those points which are not yet standardized.

Intranasal midazolam in piglets: pharmacodynamics (0.2 vs 0.4 mg/kg) and pharmacokinetics (0.4 mg/kg) with bioavailability determination.

Intranasal midazolam was studied in two series of piglets: series 1, n = 20 (18 +/- 3 kg), a randomized double blind pharmacodynamic study to compare doses of 0.2 mg/kg and 0.4 mg/kg; series 2, n = 9 (42 +/- 8 kg), a pharmacokinetic study with a 0.4 mg/kg dose administered either intravenously (i.v.) or intranasally (i.n.) in a cross-over protocol with a one-week wash-out period between each. In series 1, midazolam caused significant anxiolysis and sedation within 3 to 4 min, without a significant difference between 0.2 and 0.4 mg/kg doses for any of the studied parameters. In series 2, after intranasal midazolam administration of 0.4 mg/kg, plasma concentrations attained a maximum (Cmax) of 0.13 +/- 0.04 mg/l at 5 min (median Tmax) and remained higher than 0.04 mg/l until 60 min. The bioavailability factor (F) in this study was F = 0.64 +/- 0.17 by the intranasal route. The terminal half-life (T1/2 lambda z) = 145 +/- 138 min was comparable with the i.v. administration half-life (158 +/- 127 min). In conclusion, optimal intranasal midazolam dose in piglets was 0.2 mg/kg, which procures rapid and reliable sedation, adapted to laboratory piglets.