Cedrick Zaouter

Reduced cerebral oxygen saturation during thoracic surgery predicts early postoperative cognitive dysfunction.

BACKGROUND The objective of this prospective study is to determine cognitive dysfunction after thoracic surgery. METHODS Seventy-six patients undergoing thoracic surgery with single-lung ventilation (SLV) of an expected duration of >45 min were enrolled. Monitoring consisted of standard clinical parameters and absolute oximetry (S(ct)O(2)). The Mini-Mental State Exam (MMSE) test was used to assess cognitive function before operation and at 3 and 24 h after operation. Data were analysed using Spearman correlation test; risks for cognitive dysfunction were expressed as odds ratios. P<0.05 and data are presented as median (interquartile range). RESULTS One patient was excluded from the study. S(ct)O(2) during SLV decreased to critical values of <65%, 60%, and 55% in 40 (53%), 15 (20%), and 5 patients (7%), respectively. Twenty-two patients (29%) had a decrease of MMSE>2 points 3 h after surgery, eight patients (10%) had a decrease of MMSE>2 points 24 h after surgery. Postoperative cognitive dysfunction correlated at r(2)=0.272, 0.285, 0.297 with patient exposure times to S(ct)O(2)<65% (P=0.018), <60% (P=0.013), <55% (P=0.010), respectively. The odds ratios of developing early cognitive dysfunction ranged from 2.03 (95% CI: 0.74-5.59) for a short (<5 min) exposure to S(ct)O(2)<65% to a maximum of 9.56 (95% CI: 1.75-52.13) when S(ct)O(2) was <60% for more than 30 min. CONCLUSIONS Early cognitive dysfunction after thoracic surgery with SLV is positively related to intraoperative decline of S(ct)O(2).

Comparison of success rates, learning curves, and inter-subject performance variability of robot-assisted and manual ultrasound-guided nerve block needle guidance in simulation

BACKGROUND This study focuses on a recently developed robotic nerve block system and its impact on learning regional anaesthesia skills. We compared success rates, learning curves, performance times, and inter-subject performance variability of robot-assisted vs manual ultrasound (US)-guided nerve block needle guidance. The hypothesis of this study is that robot assistance will result in faster skill acquisition than manual needle guidance. METHODS Five co-authors with different experience with nerve blocks and the robotic system performed both manual and robot-assisted, US-guided nerve blocks on two different nerves of a nerve phantom. Ten trials were performed for each of the four procedures. Time taken to move from a shared starting position till the needle was inserted into the target nerve was defined as the performance time. A successful block was defined as the insertion of the needle into the target nerve. Average performance times were compared using analysis of variance. P<0.05 was considered significant. Data presented as mean (standard deviation). RESULTS All blocks were successful. There were significant differences in performance times between co-authors to perform the manual blocks, either superficial (P=0.001) or profound (P=0.0001); no statistical difference between co-authors was noted for the robot-assisted blocks. Linear regression indicated that the average decrease in time between consecutive trials for robot-assisted blocks of 1.8 (1.6) s was significantly (P=0.007) greater than the decrease for manual blocks of 0.3 (0.3) s. CONCLUSIONS Robot assistance of nerve blocks allows for faster learning of needle guidance over manual positioning and reduces inter-subject performance variability.

Technical communication: First robotic ultrasound-guided nerve blocks in humans using the Magellan system.

BACKGROUND:Ultrasound-guided nerve blocks are becoming a standard of modern anesthesia. We developed a robotic system, Magellan, to perform nerve blocks using a remote control center. METHODS:Thirteen patients were enrolled in this pilot study. The Magellan system consists of 3 main components: a joystick, a robotic arm, and a software control system. The joystick allows simulation of wrist or arm movements of the proceduralist. After localization of the sciatic nerve, 35 mL of bupivacaine 0.25% was injected. The success rate of sciatic nerve blocks and block performance times (performance time = interval of time from the start of the ultrasound search for the nerve to the end of the injection of the drug; robotic time = interval of time from the identification of the nerve to the end of the injection of the drug) were determined. Data are presented as median (25th, 75th; minimal, maximal) and categorical data. RESULTS:Eight men and 5 women aged 34 years were included in this study. Nerve blocks were successful in all patients. A successful attempt was defined as the introduction of the needle into the nerve sheath; motor or sensory block was not used to determine the success rate. The nerve performance time was 189 seconds (150, 233; 90, 305), whereas the robotic time was 164 seconds (121, 210; 73, 271). CONCLUSIONS:We present the first human testing of a robotic ultrasound-guided nerve block system. The success rate was 100%. The total performance time was approximately 3 minutes to 4 minutes.

The Kepler intubation system.

Our goal in this study was to develop a robotic intubation system and to conduct a feasibility pilot study on the use of a robotic intubation system for endotracheal intubations. The Kepler Intubation System was developed, consisting of a remote control center (joystick and intubation cockpit) linked to a standard videolaryngoscope via a robotic arm. Ninety intubations were performed by the Kepler Intubation System on an airway trainer mannequin by a single operator. The first group of 30 intubations was performed with the operator in direct view of the mannequin (direct view group). The second group of 30 intubations was performed with the operator unable to see the mannequin (indirect view group). Thirty semiautomated intubations were also performed during which the robotic system replayed a trace of a previously recorded intubation maneuver (semiautomated group). First-attempt success rates and intubation times for each trial were recorded. Trends were analyzed using linear regression. Data are presented as mean (SD). All intubations were successful at first attempt. The mean intubation times were 46 (18) seconds, 51 (19) seconds, and 41 (1) seconds for the direct view, indirect view, and semiautomated group, respectively. Both the direct and indirect view groups had a negative slope, denoting that each successive trial required less time. The semiautomated group had a slope of 0 and a low SD of 1 second, illustrating the high reproducibility of automated intubations. We concluded that a robotic intubation system has been developed that can allow remote intubations within 40 to 60 seconds.

Sevoflurane causes less arrhythmias than desflurane after off-pump coronary artery bypass grafting: a pilot study.

BACKGROUND Volatile anesthetics provide myocardial protection during cardiac surgery. Sevoflurane and desflurane are both efficient agents that allow immediate extubation after off-pump coronary artery bypass grafting (OPCABG). This study compared the incidence of arrhythmias after OPCABG with the two agents. MATERIALS AND METHODS Forty patients undergoing OPCABG with immediate extubation and perioperative high thoracic analgesia were included in this controlled, double-blind study; anesthesia was either provided using 1 MAC of sevoflurane (SEVO-group) or desflurane (DES-group). Monitoring of perioperative arrhythmias was provided by continuous monitoring of the EKG up to 72 hours after surgery, and routine EKG monitoring once every day, until time of discharge. Patient data, perioperative arrhythmias, and myocardial protection (troponin I, CK, CK-MB-ratio, and transesophageal echocardiography examinations) were compared using t-test, Fishers exact test or two-way analysis of variance for repeated measurements; P < 0.05. RESULTS Patient data and surgery-related data were similar between the two groups; all the patients were successfully extubated immediately after surgery, with similar emergence times. Supraventricular tachycardia occurred only in the DES-group (5 of 20 patients), atrial fibrillation was significantly more frequent in the DES group versus SEVO-group, at five out of 20 versus one out of 20 patients, respectively. Myocardial protection was equally achieved in both groups. DISCUSSION Ultra-fast track anesthesia using sevoflurane seems more advantageous than desflurane for anesthesia, for OPCABG, as it is associated with significantly less atrial fibrillation or supraventricular arrhythmias after surgery.

Feasibility of Automated Propofol Sedation for Transcatheter Aortic Valve Implantation: A Pilot Study.

BACKGROUND: Recently, several trials have shown that closed-loop sedation is feasible. No study has used automated sedation in extremely frail patients, such as those scheduled for transcatheter aortic valve implantation (TAVI). We developed and tested a novel automated sedation system for this kind of population and surgery. The system integrates a decision support system that detects respiratory and hemodynamic events via smart alarms, which provide pertinent/related clinical suggestions and treatment options. The main objective was the feasibility of closed-loop sedation, defined as successful automated sedation without manual override. Secondary qualitative observations were clinical and controller performance. METHODS: Twenty patients scheduled for elective TAVI were enrolled. Sedation was administered via a closed-loop delivery system designed for propofol. The clinical performance of sedation was the efficacy to maintain a bispectral index (BIS) of 65. To evaluate the sedation performance, BIS values were stratified into 4 categories: excellent, very good, good, and inadequate sedation control, defined as BIS values within 10%, ranging from 11% to 20%, ranging from 21% to 30%, or >30% from the target value, respectively. The controller performance was calculated using Varvel parameters. Critical respiratory and hemodynamic events were documented. The former was defined as peripheral oxygen saturation <92% and/or respiratory rate <8/min, whereas the latter was considered a mean arterial pressure <60 mm Hg and/or heart rate <40 bpm. RESULTS: Automated sedation was successful in 19 patients undergoing TAVI. One patient was excluded from the final analysis because of conversion to general anesthesia. The secondary observations revealed that the clinical performance allowed an excellent to good control during 69% (99% confidence interval, 53%–77%; interquartile range, 59%–79%) of the sedation time. Fifteen patients presented critical respiratory episodes, with a median of 3 events per hour of sedation. Six patients presented critical hemodynamic episodes, with a median of 2 events per hour of procedure. CONCLUSIONS: The automated closed-loop sedation system tested could be used successfully for patients scheduled for a TAVI procedure. The results showed a satisfactory clinical performance of sedation control.

A combined approach for the early recognition of acute kidney injury after adult cardiac surgery

BACKGROUND Cardiac surgery-associated acute kidney injury (CSA-AKI) is a frequent complication. The current criteria to detect CSA-AKI rise only when organic dysfunction has occurred. The Doppler Renal Resistive Index (RRI) and the urinary G1 cell cycle arrest proteins (TIMP-2 and IGFBP7) have been advocated to predict CSA-AKI at an early stage after cardiac surgery. The primary objective was to determine the predictive value of these new markers to detect CSA-AKI after elective heart surgery in patients at risk to develop AKI. METHODS In a prospective observational trial, we studied 50 patients scheduled for elective on-pump heart surgery at high risk for CSA-AKI. The primary outcome was the incidence of AKI according to the KDIGO criteria recording the urine output every hour until ICU discharge and measuring the serum creatinine levels on each postoperative day until the post-procedure peak values were reached or until the 7th postoperative day. The RRI and the urinary proteins [TIMP-2]*[IGFBP7] were measured concomitantly: before surgery, 1hour (H1), 4-hour (H4), 12-hour (H12), and 24-hour (H24) after surgery. RESULTS Thirty-seven patients (74%) developed CSA-AKI. Urinary [TIMP-2]*[IGFBP7] at H12 were significantly higher in patients that developed AKI (0.62, [interquartile] [0.20-1.18] vs. 0.30 [0.07-0.47] P=0.044) with an area under the receiver-operating characteristic curve of 0.69 [0.53-0.84]. The best sensitivity (65%) and specificity (62%) was achieved for a cutoff value of 0.3 (ng.mL-1)2.1000-1. The H12 time-point was the only in which the RRI values measured showed a trend toward statistical significance in patients that developed AKI (0.72 (Standard deviation)±(0.06) vs. 0.68±(0.07) P=0.065). The combination of the two markers ([TIMP-2]*[IGFBP7]+RRI) at H12 showed an increased performance of the accuracy with an area under the receiver-operating characteristic curve of 0.78 [0.62-0.93]. CONCLUSIONS In a population at risk of developing CSA-AKI, neither the RRI nor urinary [TIMP-2]*[IGFBP7] detect CSA-AKI occurring in the first post-operative week within the first 24 postoperative hours.

A Short Update on Sugammadex with a Special Focus on Economic Assessmentof its Use in North America

Sugammadex offers significant advantages over the current anticholinesterase reversal drugs. Sugammadex used has been approved for the United Stated and for Canada since December 2015 and February 2016, respectively. The present article aims to provide a straightforward and concise review of the most recent literature describing its clinical advantages in routine use. A thorough and cost-effective evaluation has been conducted specifically for North America to determine if its price justifies its inclusion into regular patients’ care. The search examined the relevant literature from January 2013 to October 2016. The present narrative review describes how sugammadex could play a crucial role in the modern conduct of anesthesia. The particular emphasis on sugammadex cost-effective analysis performed in this article suggests that this new reversal agent should be considered for a wider use in North America.

Impact of age on anaesthesiologists’ competence: A narrative review

The international anaesthesia community is getting older, in line with trends worldwide, and as men and women age there is the risk that psychophysiological decline could have an impact on clinical practice. Impairment of technical and nontechnical skills could have a negative impact on patients’ safety and outcomes. The ageing process may not necessarily go hand-in-hand with a predictable pattern of decreased competence as not all aspects of functional decline are affected at the same rate and to the same extent. The development of simulation has provided a means of detecting and perhaps reversing the decline in ability associated with age. The introduction of recertification based on an assessment of competence at simulation sessions could play a crucial role in maintaining a high standard of patient care and an appropriate level of patient safety.