Reversal of neuromuscular blockade with sugammadex during continuous administration of anaesthetic agents: a double-blind randomised crossover study using the bispectral index.

Sugammadex, a specific reversal agent for steroidal neuromuscular blocking drugs, has on occasion been reported to be associated with clinical signs of awakening. We performed a study to systematically search for an increase in bispectral index values and signs of awakening in patients maintained under general anaesthesia following sugammadex administration. Patients, scheduled to receive general anaesthesia with neuromuscular blockade, were included in this double-blind randomised crossover study. After surgery was completed, and while the train-of-four ratio was zero, intravenous anaesthesia was continued with the aim of maintaining the bispectral index in the range of 40-60. Patients then received either sugammadex 4 mg.kg-1 or saline. In cases of incomplete reversal of neuromuscular blockade after 5 min, patients received the other drug. Bispectral index and train-of-four monitoring were recorded every minute and clinical signs of awakening noted. Fifty-one patients completed the study. Median (IQR [range]) bispectral index values increased after sugammadex administration from 49 (43-53 [38-64]) to 63 (53-80 [45-97]) (p < 0.01) with an increase of ≥ 20 in 22 patients; 14 (27%) patients had clinical signs of awakening. Saline had no effect on bispectral index values, clinical signs of awakening or degree of neuromuscular blockade. This study confirms that reversal of neuromuscular blockade with sugammadex may be associated with clinical signs of awakening despite maintenance of anaesthesia. Intravenous anaesthesia should be maintained until complete recovery of muscle function is achieved, especially when sugammadex is administered.

Presence of anesthesiologists and nurses in the operating room: Liability of surgeons and health care facilities.

The presence of an anesthesiologist and certified registered nurse anesthesiologist in the operating room remains a topic of discussion in many facilities. This article provides an overview on the legislation and recommendations on this topic and recounts some of the related jurisprudence. The opinions of various actors, surgeons, anesthesiologists, anesthesiology-intensive care physicians, certified registered nurse anesthesiologists, care-facility directors and insurance companies are included. Based on these elements, we attempt to answer the question of presence of competence in anesthesiology in the operating room.

Skin conductance as a pain assessment tool during chest tube removal: An observational study.

BACKGROUND: Skin conductance variability to assess pain has shown varying results. Skin conductance responses per second (SCR) during a standardized painful stimulus in awake adults may give further understanding of the method's validity. The purpose of this study was to validate the SCR with the visual analogue scale (VAS) for pain (P-VAS) and anxiety (A-VAS) during chest tube removal (CTR). METHODS: Ninety-five patients receiving epidural or non-epidural treatment, scheduled for CTR, were studied. Pain or anxiety was considered when VAS > 30 mm; the SCR cut-off value reflecting pain was ≥0.2 SCR. RESULTS: SCR values could not be recorded in eight cases before CTR, six cases during CTR and seven cases after CTR. CTR induced increases in SCR, P-VAS and A-VAS (p < 0.001). Seventy-seven percent of all pairs of P-VAS and SCR values were well-classified; P-VAS ≤ 30 mm and SCR < 0.2 or P-VAS > 30 mm and SCR ≥ 0.2. SCR obtained before CTR differentiates between patients with and without pain during CTR in all patients (p = 0.04) and in the subgroup of non-anxious patients (p = 0.02), but not in the subgroup of anxious patients. SCR obtained during CTR had similar values in patients with and without pain in all patients and in the subgroup of anxious patients, but in the subgroup of non-anxious patients SCR during CTR differentiates patients with and without pain (p = 0.009). CONCLUSIONS: SCR increases during painful procedures. Preprocedural SCR may help predict reported pain in patients exposed to painful procedures. SCR during CTR differentiates between patients with and without pain only in non-anxious patients. SIGNIFICANCE: Preprocedural SCR may help predict reported pain in patients exposed to painful procedures. Procedural SCR accuracy improves in a subgroup of non-anxious patients. P-VAS is influenced by anxiety different from SCR.

Immediate postoperative extubation in bilateral lung transplantation: predictive factors and outcomes.

BACKGROUND: We reviewed our experience with tracheal extubation in the operating room (E-OR) among cystic fibrosis patients requiring bilateral lung transplantation to evaluate safety and determine predictive factors of E-OR. METHODS: The charts of 89 recipients (from May 2007 to June 2013) were analysed. Patients were divided into E-OR and E-ICU (intensive care unit extubation) groups. Data are expressed as numbers (percentages) or medians [25th-75th percentiles]. RESULTS: There were 41 patients in the E-OR group (46%). Donor and recipient characteristics were similar between groups. Intraoperative complications occurred less frequently in the E-OR group, and fluid and transfusion requirements were lower. Postoperative courses were different in the E-OR group, including a lower rate of grade 3 primary graft dysfunction (0 compared with 19 patients, P<0.0001) and shorter ICU (5.0 [3.7-7.2] compared with 11.5 [7.0-15.5] days) and hospital stays (22.0 [18.0-25.5] compared with 33.0 [25.0-56.5] days, respectively; P<0.0001 for both). The 1 yr survival rates were similar: 95% in the E-OR group and 98% in the E-ICU group. A statistical model built on a development cohort of 60 randomly selected patients predicted 95% of E-OR instances in this cohort and 82% of E-OR instances in the validation cohort (28 patients). Predictive factors were complications during single-lung ventilation (second graft implantation), complications during bipulmonary ventilation (end of surgery), and the ratio of arterial partial pressure of oxygen to fractional inspired oxygen (end of surgery). CONCLUSIONS: Our protocol allowed for extubation of 46% of bilateral lung transplant patients without increased postoperative risks.

Feasibility of closed-loop co-administration of propofol and remifentanil guided by the bispectral index in obese patients: a prospective cohort comparison.

BACKGROUND: We used an automated bispectral index (BIS)-guided dual-loop controller to determine propofol and remifentanil requirements during general anaesthesia in obese and lean surgical patients. METHODS: Obese patients, BMI>35 kg m(-2), and lean patients (<25 kg m(-2)) having laparoscopic procedures were prospectively evaluated in this multicentre single-blind study. The automated controller targeted BIS between 40 and 60 by adjusting propofol and remifentanil administration. Propofol and remifentanil consumptions were calculated using both total body weight (TBW) and ideal body weight (IBW). Results are expressed as medians (inter-quartile range). RESULTS: Thirty obese [BMI=43 (40-49) kg m(-2)] and 29 lean [BMI=23 (21-25) kg m(-2)] patients completed the study. BIS was between 40 and 60 during 84 (69-91)% vs 85 (78-92)% of the anaesthetic time, P=0.46. The amount of propofol given during induction [1.2 (1.1-1.6) vs 1.3 (1.0-1.7) mg kg(-1), P=0.47] and maintenance [5.2 (4.1-6) vs 5.3 (4.7-6.4) mg kg(-1) h(-1), P=0.39] calculated using TBW was similar between the two groups. The dual-loop controller delivered half as much remifentanil to the obese patients during induction [1.0 (0.8-1.6) vs 2.2 (1.5-2.7) µg kg(-1), P<0.001] and maintenance [0.12 (0.07-0.16) vs 0.25 (0.17-0.29) µg kg(-1) min(-1), P<0.001] calculated using TBW. But when remifentanil consumption was calculated using IBW, the amounts were similar during induction at 2.2 (1.6-3.5) vs 2.0 (1.6-3.0) µg kg(-1) IBW, P=0.48, and during maintenance at 0.26 (0.16-0.34) vs 0.27 (0.18-0.33 ) µg kg(-1) min(-1), P=0.50. CONCLUSIONS: The amount of propofol-remifentanil administered by the controller is consistent with current knowledge, propofol is best dosed using TBW whereas remifentanil is best dosed using IBW. CLINICAL TRIAL REGISTRATION: NCT00779844.

6% Hydroxyethyl starch (130/0.4) vs Ringer's lactate preloading before spinal anaesthesia for Caesarean delivery: the randomized, double-blind, multicentre CAESAR trial.

BACKGROUND: Vasopressor administration is recommended to prevent hypotension during spinal anaesthesia (SA) for elective Caesarean delivery. We aimed to test the superior efficacy and ensure safety of a hydroxyethyl starch (HES) vs a Ringer's lactate (RL) preloading, when combined with a phenylephrine-based prophylaxis. METHODS: A total of 167 healthy parturients undergoing elective Caesarean delivery under SA were included in this multicentre, randomized, double-blind study. Patients received 500 ml of 6% HES (130/0.4)+500 ml of RL (HES group) or 1000 ml of RL (RL group) i.v. before SA. After SA, i.v. phenylephrine boluses were titrated when systolic arterial pressure (SAP) was below 95% of baseline. The primary outcome was the incidence of maternal hypotension (SAP <80% of baseline). RESULTS: The incidence of both hypotension and symptomatic hypotension (i.e. with dizziness, nausea/vomiting, or both) was significantly lower in the HES group vs the RL group: 36.6% vs 55.3% (one-sided P=0.025) and 3.7% vs 14.1%. There was no significant difference in total phenylephrine requirements [median (range): 350 (50-1800) vs 350 (50-1250) µg]. The decrease in maternal haemoglobin value the day after surgery was similar in the two groups [1.2 (1.0) vs 1.0 (0.9) g dl(-1)]. There was no detectable placental transfer of HES in six umbilical cord blood samples analysed in the HES group. Neonatal outcomes were comparable between the groups. CONCLUSIONS: Compared with a pure RL preloading, a mixed HES-RL preloading significantly improved prevention of both hypotension and symptomatic hypotension based on early phenylephrine bolus administration and did not induce adverse effects. CLINICAL TRIAL REGISTRATION: NCT00694343 (http://clinicaltrials.gov).

[One-lung ventilation in a patient with a tracheal bronchus]. / Ventilation unipulmonaire chez une patiente présentant une trifurcation bronchique.

We report a patient in whom a tracheal bronchus was discovered intraoperatively during an endoscopy control. This observation led us to a focus on what to do in such cases.

Use of the Nexfin™ device to detect acute arterial pressure variations during anaesthesia induction.

BACKGROUND: Standard non-invasive arterial pressure (AP) measurements are discontinuous. By providing non-invasive beat-to-beat AP measurements, Nexfin™ might limit duration of intraoperative hypotension and hypertension. We assessed the ability of Nexfin™ to detect AP variations by comparing its trending ability with invasive AP monitoring. METHODS: Thirty-one subjects undergoing elective surgery under general anaesthesia were included. During induction, simultaneous pairs of AP measurements were collected every 5 s from the Nexfin™ finger sensor and a homolateral radial artery catheter. Magnitude and time lags of AP variations from baseline to nadir and peak were calculated for both methods. Concordance analysis was performed by the Bland-Altman method (for comparison of repeated measures when appropriate). RESULTS: Nexfin™ detected 100% of AP changes with the median delays of 0 s (-13 to 7) and 0 s (-5 to 12) for nadir and peak, respectively. Bias [limits of agreement (LOA)] of systolic AP (SAP) variations was -0.5 mm Hg (-31.2 to 30.2) and -9.4 mm Hg (-31.3 to 12.6) from baseline to nadir and from baseline to peak, respectively. For 3479 analysed paired measurements, bias was -3.8 and -8.8 mm Hg for SAP and diastolic AP, with LOA of (-36.0 to 28.5) and (-29.8 to 12.3), respectively. CONCLUSIONS: Nexfin™ detects AP variations accurately and can be a useful warning device during anaesthesia. However, it is not interchangeable with invasive monitoring, given the large LOA between the two measurements. CLINICAL TRIAL REGISTRATION: NCT01658631.

Nitrous oxide does not produce a clinically important sparing effect during closed-loop delivered propofol-remifentanil anaesthesia guided by the bispectral index: a randomized multicentre study.

BACKGROUND: Nitrous oxide (N2O) offers both hypnotic and analgesic characteristics. We therefore tested the hypothesis that N2O administration decreases the amount of propofol and remifentanil given by a closed-loop automated controller to maintain a similar bispectral index (BIS). METHODS: In a randomized multicentre double-blind study, patients undergoing elective surgery were randomly assigned to breathe 60% inspired N2O (N2O group) or 40% oxygen (AIR group). Anaesthesia depth was evaluated by the proportion of time where BIS was within the range of 40-60 (BIS40-60). The primary outcomes were propofol and remifentanil consumption, with reductions of 20% in either being considered clinically important. RESULTS: A total of 302 patients were randomized to the N2O group and 299 to the AIR group. At similar BIS40-60 [79 (67-86)% vs 76 (65-85)%], N2O slightly decreased propofol consumption [4.5 (3.7-5.5) vs 4.8 (4.0-5.9) mg kg(-1) h(-1), P=0.032], but not remifentanil consumption [0.17 (0.12-0.23) vs 0.18 (0.14-0.24) µg kg(-1) min(-1)]. For the subgroups of men, at similar BIS40-60 [80 (72-88)% vs 80 (70-87)%], propofol [4.2 (3.4-5.3) vs 4.4 (3.6-5.4) mg kg(-1) h(-1)] and remifentanil [0.19 (0.13-0.25) vs 0.18 (0.15-0.23) µg kg(-1) min(-1)] consumptions were similar in the N2O vs AIR group, respectively. For the subgroups of women, at similar BIS40-60 [76 (64-84)% vs 72 (62-82)%], propofol [4.7 (4.0-5.8) vs 5.3 (4.5-6.6) mg kg(-1) h(-1), P=0.004] and remifentanil [0.18 (0.13-0.25) vs 0.20 (0.15-0.27) µg kg(-1) min(-1), P=0.029] consumptions decreased with the co-administration of N2O. CONCLUSIONS: With automated drug administration titrated to comparable BIS, N2O only slightly reduced propofol consumption and did not reduce remifentanil consumption. There was a minor gender dependence, but not by a clinically important amount. Clinical trial registration This study was registered at ClinicalTrials.gov, number NCT00547209.

Population pharmacokinetics of tranexamic acid in adults undergoing cardiac surgery with cardiopulmonary bypass.

BACKGROUND: Interest in antifibrinolytic tranexamic acid (TA) has grown since the widespread removal of aprotinin, but its dosing during cardiac surgery is still debated. The objectives of this study were to investigate the population pharmacokinetics (PK) of TA given with either low- or high-dose continuous infusion schemes in adult cardiac surgery patients during cardiopulmonary bypass (CPB). METHODS: Patients were randomized to receive either low-dose (10 mg kg(-1) followed by an infusion of 1 mg kg(-1) h(-1) throughout the operation, and 1 mg kg(-1) into the CPB) or high-dose (30 mg kg(-1), then 16 mg kg(-1) h(-1), and 2 mg kg(-1) into the CPB) TA. Serum TA concentrations were measured in 61 patients and the data were modelled using Monolix. RESULTS: TA concentrations were 28-55 µg ml(-1) in the low-dose group and 114-209 µg ml(-1) in the high-dose group throughout surgery. TA PK was best described by a two-compartment open model. The main covariate effect was bodyweight, whereas the CPB did not influence the PK. Assuming a bodyweight of 70 kg, the population estimates were 4.8 litre h(-1) for clearance, 6.6 litre for the volume of the central compartment, 32.2 litre h(-1) for the diffusional clearance, and the peripheral volume of distribution was 10.8 litre. CONCLUSIONS: The PK of TA was satisfactorily described by an open two-compartmental model, which was used to propose a dosing scheme suitable for obtaining and maintaining the desired plasma concentration in a stable and narrow range in cardiac surgery patients.

CNAP(®) does not reliably detect minimal or maximal arterial blood pressures during induction of anaesthesia and tracheal intubation.

BACKGROUND: CNAP(®) provides continuous non-invasive arterial pressure (AP) monitoring. We assessed its ability to detect minimal and maximal APs during induction of general anaesthesia and tracheal intubation. METHODS: Fifty-two patients undergoing surgery under general anaesthesia were enrolled. Invasive pressure monitoring was established at the radial artery, and CNAP monitoring using a finger sensor recording was begun before induction. Statistical analysis was conducted with the Bland-Altman method for comparison of repeated measures and intraclass correlation coefficient (ICC). RESULTS: Patients' median age was 67 years [interquartile range (59-76)], median American Society of Anesthesiologists score was 3 [interquartile range (2-3)]. Bias was 5 and -7 mmHg for peak and nadir systolic AP (SAP), with upper and lower limits of agreement of (42:-32) and (27;-42), respectively. The corresponding ICC values were 0.74 [95% confidence interval (CI) = 0.57-0.84] and 0.60 (95% CI = 0.44-0.73). Time lags to reach these values were 7.5 s (95% CI = -10.0 to 60.0) for the highest SAP and 10 s (95% CI = -12.5 to 72.5) for the lowest SAP. Bias, lower and upper limits of agreement for diastolic, and mean AP were -14 (-36 to 9) and -12 (-37 to 13) for the nadir value and -7 (-29 to 15) and -2 (-28 to 25) for the peak value. CONCLUSIONS: The CNAP monitor could detect acute change in AP within a reasonable time lag. Precision of its measurements is not satisfactory, and therefore, it could only serve as a clue to the occurrence of changes in AP.

The Analgesia Nociception Index: a pilot study to evaluation of a new pain parameter during labor.

BACKGROUND: Objective pain assessment that is not subject to influences from either cultural or comprehension issues is desirable. Analysis of heart rate variability has been proposed as a potential method. This pilot study aimed to assess the performance of the PhysioDoloris™ analgesia monitor which calculates an Analgesia Nociception Index derived from heart rate variability. It was compared with visual analogical pain scores. METHODS: Forty-five parturients who requested epidural analgesia were recruited. Simultaneous couplets of pain scores and Analgesia Nociception Index values were recorded every 5 min regardless of the presence or absence of uterine contractions. The relationship between indices was characterized, and a cut-off value of Analgesia Nociception Index corresponding to a visual analogical score >30 (range 0-100) was used to determine the positive and negative predictive value of the Analgesia Nociception Index. RESULTS: There was a negative linear relationship between visual analogical pain scores and Analgesia Nociception Index values regardless of the presence of uterine contractions (regression coefficient ± SEM=-0.18 ± 0.032 for entire dataset). Uterine contraction significantly reduced the Analgesia Nociception Index (P<0.0001). Using a visual analogical pain score >30 to define a painful sensation, the lower 95% confidence limit for the Analgesia Nociception Index score was 49. CONCLUSION: The Analgesia Nociception Index has an inverse linear relationship with visual analogical pain scores. Further studies are necessary to confirm the results of this pilot study and to look at the influence of epidural analgesia on the Analgesia Nociception Index.

Effect of age on the comparability of bispectral and state entropy indices during the maintenance of propofol-sufentanil anaesthesia.

BACKGROUND: Manufacturers recommend maintaining anaesthesia at a bispectral index (BIS) or state entropy (SE) index value between 40 and 60. METHODS: We prospectively studied 102 patients receiving propofol-sufentanil anaesthesia administered by anaesthetists blinded to these indices. The main endpoint was crude agreement (P(0)), defined as the proportion of agreement between BIS and SE index among three categories: <40, between 40 and 60, and >60. Discrepancies in recommendation (DR) were also considered. A DR is type 1 if BIS or SE is <40, while the other is simultaneously >60. A DR is type 2 when BIS and SE index values are on different sides of a threshold (40 or 60) with three subtypes according to the magnitude of their difference. A linear multiple regression was performed to identify covariates that are independently associated with P(0). RESULTS: In total, 12 147 pairs of values were studied. P(0) was 59.9 (24.5%) [mean (sd)]. Thirty-three patients presented more than 50% discordant pairs and only seven patients presented more than 95% concordant pairs. Type 1 DR occurred in only 1.1% of all the pairs. The median (inter-quartile range) number of type 2 DR varied from 5 (3-8) to 2 (1-3) according to the degree of difference. Multivariate analysis showed that age (P=0.0004) and electrode position (P=0.0084) were independently associated with P(0). An increase in the age of 10 yr decreases P(0) by 5%. CONCLUSIONS: The agreement between BIS and SE indices is moderate and deteriorates as patients' age increases. This study cannot determine which index is best adapted for elderly patients. Additional work comparing both indices with raw EEG traces is warranted.

Preferential adhesion of silver nanoparticles onto crystal faces of alpha-cyclodextrin/carboxylic acids inclusion compounds.

Alpha-Cyclodextrin (alpha-CD) inclusion compounds containing the carboxylic acids (octanoic, decanoic, lauric or dodecanoic, myristic or tetradecanoic, palmitic or hexadecanoic and stearic or octadecanoic) as guests were synthesized and applied for preferential adhesion of silver nanoparticles (AgNPs). The binding affinity depends of the chain length of the respective guest and is most efficient for octanoic and decanoic acids. The immobilization of nanoparticles is caused by the spatial replacing of the stabilized shell of the nanoparticles by COOH groups of the guests molecules, located at the entrance of cavity of alpha-CD, corresponding to the {001} crystal plane. Crystalline coating with nanoparticles provides a means of storing of AgNPs on solids state without aggregation. The stabilization of the particles on the surface is valid for a given length and ordering of the guest in the cavities of the alpha-CD being the octanoic and decanoic acid the most appropriated.

[Emergency interventional bronchoscopies]. / Bronchoscopies interventionnelles en urgence.

An emergency interventional endoscopic procedure is often the only way to overcome an asphyxic or pre-asphyxic situation. From November 1978 to June 2010 we performed 9950 interventional endoscopies among which 20% were performed in an emergency context. To obtain a homogeneous study group, we reviewed the last four years. 344 interventional emergency endoscopies were done for the following indications: cancers (n=240, 70%), iatrogenic stenosis (n=63, 18%), foreign bodies (n=29, 8.5%), hemoptysis (12, 3.5%). The same technique was used in all cases: operating room, general anesthesia, rigid bronchoscope, laser, cryotherapy. Outcome was favorable in 85% of cancers and 100% in all other indications. Apart from clear-cut cases, it remains difficult to define the true emergency. Whatever the definition retained, a well-trained anesthetic and endoscopic team is crucial for proper intervention in these potentially life-threatening situations.