Mohamad Wehbe

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.

First robotic tracheal intubations in humans using the Kepler intubation system

BACKGROUND Intubation is one of the most important anaesthetic skills. We developed a robotic intubation system (Kepler intubation system, KIS) for oral tracheal intubation. METHODS In this pilot study, 12 patients were enrolled after approval of the local Ethics board and written informed consent. The KIS consists of four main components: a ThrustMaster T.Flight Hotas X joystick (Guillemot Inc., New York, NY, USA), a JACO robotic arm (Kinova Rehab, Montreal, QC, Canada), a Pentax AWS video laryngoscope (Ambu A/S, Ballerup, Denmark), and a software control system. The joystick allows simulation of the wrist or arm movements of a human operator. The success rate of intubation and intubation times were measured. RESULTS Eleven men and one woman aged 66 yr were included in this study. Intubation was successful in all but one patient using KIS at a total time of [median (inter-quartile range; range)] 93 (87, 109; 76, 153) s; in one patient, fogging of the video laryngoscope prevented intubation using KIS. CONCLUSIONS We present the first human testing of a robotic intubation system for oral tracheal intubation. The success rate was high at 91%. Future studies are needed to assess the performance and safety of such a system.

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.

A technical description of a novel pharmacological anesthesia robot.

To control the three components of general anesthesia (hypnosis, analgesia, and neuromuscular blockade), an automated closed-loop, anesthesia-drug delivery system (McSleepy) was developed. Bispectral index was used as the control variable for hypnosis, the analgoscore for analgesia, and phonomyography for neuromuscular blockade. McSleepy can be used to control the induction, maintenance and emergence from general anesthesia. To do so, a large touch screen is used to provide a user friendly interface, permitting bidirectional communication: the user giving information about the different stages of anesthesia, and the system prompting the anesthesiologist to perform certain actions such as mask ventilation, intubation or waking-up the patient using audio clips with voice commands. Several safety features were implemented to provide a secure and reliable anesthesia. Preliminary results of 15 patients are presented in this paper. Evaluation of McSleepy was done through an assessment of its clinical performance and using Varvel’s performance indices. The system was found to be clinically useful by providing good precision in drug administration and reliable results for the duration of a general anesthesia.

Robotics and regional anesthesia.

Purpose of review Robots in regional anesthesia are used as a tool to automate the performance of regional techniques reducing the anesthesiologists workload and improving patient care. The purpose of this review is to show the latest findings in robotic regional anesthesia. Recent findings The literature separates robots in anesthesia into two groups: pharmacological robots and manual robots. Pharmacological robots are mainly closed-loop systems that help in the titration of anesthetic drugs to patients undergoing surgery. Manual robots are mechanical robots that are used to support or replace the manual gestures performed by anesthesiologists. Although in the last decade researchers have focused on the development of decision support systems and closed-loop systems, more recent evidence supports the concept that robots can also be useful in performing regional anesthesia techniques. Summary Robots can improve the performance and safety in regional anesthesia. In this review, we present the developments made in robotic and automated regional anesthesia, and discuss the current state of research in this field.

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.

Magellan: Technical Description of a New System for Robot-Assisted Nerve Blocks

Nerve blocks are common procedures used to remove sensation from a specific region of the body via injection of local anesthetic. Ultrasound-guided nerve blocks are common-place in anesthesia, but require specialized training and advanced bi-manual dexterity. This paper describes a system designed to robotically assist in ultrasound-guided nerve blocks. Robot-assisted nerve blocks could allow for more precise needle placement, and therefore a higher efficacy of blocks. This system is the first step in developing a completely automated nerve block system, which would also require the incorporation of ultrasound image recognition of nerves and other physiological markers.

NerveGPS: A Novel Decision Support System for Ultrasound Nerve Block Guidance

Peripheral regional nerve blockade (nerve block) is used in anesthesia to administer anesthesia to certain regions of the body. During nerve block the anesthetic is injected directly into or around the area surrounding the nerve. One of the most critical components of ultrasound-guided nerve blocks is the detection of the nerve within the ultrasound image. This study presents a software-based solution for the detection of nerves within the ultrasound feed. The software that was developed used image processing tools to detect the location of the sciatic nerve at the popliteal fossa within an ultrasound feed. For the study, 100 images were obtained from authors. Then, 2 anesthesiologists with experience in ultrasound-guided nerve blocks were asked to identify the contour of the nerve in the obtained images. The study used two criteria for evaluating the software: 1) the location of the software determined nerve center fell within the manually defined contour and 2) the percentage of overlap between the software and manually detected areas. A test was successful if the percentage of overlap between automatic and manual detection was a minimum of 95% for a circle of 0.4cm diameter centered at the software detected nerve center. For the 100 image sample, the nerve was detected within the manually detected area in 99% of the cases, with an overlap of 98% for a 0.4cm diameter circle. Time to detect the nerve ranged from 0.95s to 1.6s. These preliminary results show that the nerve detection software provides a reliable target for needle insertion. Future work will extend the software to different nerves of interest.

Relaxofon: A neuromuscular blockade monitor for patients under general anesthesia

Anesthesia consists of three components: unconsciousness, analgesia and neuromuscular blockade (NMB). A specific drug is administered by the anesthesiologist to control these different components. In this paper we propose a new system for monitoring the neuromuscular blockade in anesthesized patients during surgery. Neuromuscular blockade drugs are used routinely by clinicians to induce muscle relaxation in patients. However, the use of these drugs has some risks, so an adequate monitoring of the effects of these drugs is essential. This paper describes the Relaxofon, a NMB monitoring device based on phonomyography. The Relaxofon is composed of a hardware subsystem that records muscle sounds using microphones and a special circuit to filter out the noise and amplify the signal, and a software subsystem that analyses the acquired signal. We tested the ability of the system to record phonomyographic signals from the adductor pollicis and the corrugator supercilii muscles. We then performed the Bland-Altman test to compare the manual Train-of-Four ratio (a measure of the depth of muscle relaxation) calculation against the one performed by the Relaxofon. Finally, we calculated the Pearson correlation coefficient to measure the linear dependence between the two methods. Automatic Train-of-Four ratio calculations using this system showed very good agreement with manual calculations. Results from this work may ultimately lead to integration of NMB monitoring to an automated closed-loop anesthesia system.