Surgical Intelligence can Lead to Higher Adoption of Best Practices in Minimally Invasive Surgery.

OBJECTIVE: To examine the use of surgical intelligence for automatically monitoring critical view of safety (CVS) in laparoscopic cholecystectomy (LC) in a real-world quality initiative. BACKGROUND: Surgical intelligence encompasses routine, AI-based capture and analysis of surgical video, and connection of derived data with patient and outcomes data. These capabilities are applied to continuously assess and improve surgical quality and efficiency in real-world settings. METHODS: LCs conducted at two general surgery departments between December 2022 and August 2023 were routinely captured by a surgical intelligence platform, which identified and continuously presented CVS adoption, surgery duration, complexity, and negative events. In March 2023, the departments launched a quality initiative aiming for 75% CVS adoption. RESULTS: 279 procedures were performed during the study. Adoption increased from 39.2% in the 3 pre-intervention months to 69.2% in the final 3 months (P < .001). Monthly adoption rose from 33.3% to 75.7%. Visualization of the cystic duct and artery accounted for most of the improvement; the other two components had high adoption throughout. Procedures with full CVS were shorter (P = .007) and had fewer events (P = .011) than those without. OR time decreased following intervention (P = .033). CONCLUSION: Surgical intelligence facilitated a steady increase in CVS adoption, reaching the goal within 6 months. Low initial adoption stemmed from a single CVS component, and increased adoption was associated with improved OR efficiency. Real-world use of surgical intelligence can uncover new insights, modify surgeon behavior, and support best practices to improve surgical quality and efficiency.

Automated Identification of Key Steps in Robotic-Assisted Radical Prostatectomy Using Artificial Intelligence.

PURPOSE: The widespread use of minimally invasive surgery generates vast amounts of potentially useful data in the form of surgical video. However, raw video footage is often unstructured and unlabeled, thereby limiting its use. We developed a novel computer-vision algorithm for automated identification and labeling of surgical steps during robotic-assisted radical prostatectomy (RARP). MATERIALS AND METHODS: Surgical videos from RARP were manually annotated by a team of image annotators under the supervision of 2 urologic oncologists. Full-length surgical videos were labeled to identify all steps of surgery. These manually annotated videos were then utilized to train a computer vision algorithm to perform automated video annotation of RARP surgical video. Accuracy of automated video annotation was determined by comparing to manual human annotations as the reference standard. RESULTS: A total of 474 full-length RARP videos (median 149 minutes; IQR 81 minutes) were manually annotated with surgical steps. Of these, 292 cases served as a training dataset for algorithm development, 69 cases were used for internal validation, and 113 were used as a separate testing cohort for evaluating algorithm accuracy. Concordance between artificial intelligence‒enabled automated video analysis and manual human video annotation was 92.8%. Algorithm accuracy was highest for the vesicourethral anastomosis step (97.3%) and lowest for the final inspection and extraction step (76.8%). CONCLUSIONS: We developed a fully automated artificial intelligence tool for annotation of RARP surgical video. Automated surgical video analysis has immediate practical applications in surgeon video review, surgical training and education, quality and safety benchmarking, medical billing and documentation, and operating room logistics.

Routine Automated Assessment Using Surgical Intelligence Reveals Substantial Time Spent Outside the Patient's body in Minimally Invasive Gynecological Surgeries.

OBJECTIVE: To demonstrate the use of surgical intelligence to routinely and automatically assess the proportion of time spent outside of the patient's body (out-of-body-OOB) in laparoscopic gynecological procedures, as a potential basis for clinical and efficiency-related insights. DESIGN: A retrospective analysis of videos of laparoscopic gynecological procedures. SETTING: Two operating rooms at the Gynecology Department of a tertiary medical center. PARTICIPANTS: All patients who underwent laparoscopic gynecological procedures between January 1, 2021 and December 31, 2022 in those two rooms. INTERVENTIONS: A surgical intelligence platform installed in the two rooms routinely captured and analyzed surgical video, using AI to identify and document procedure duration and the amount and percentage of time that the laparoscope was withdrawn from the patient's body per procedure. RESULTS: A total of 634 surgical videos were included in the final dataset. The cumulative time for all procedures was 639 hours, of which 48 hours (7.5%) were OOB segments. Average OOB percentage was 8.7% (SD = 8.7%) for all the procedures and differed significantly between procedure types (p < .001), with unilateral and bilateral salpingo-oophorectomies showing the highest percentages at 15.6% (SD = 13.3%) and 13.3% (SD = 11.3%), respectively. Hysterectomy and myomectomy, which do not require the endoscope to be removed for specimen extraction, showed a lower percentage (mean = 4.2%, SD = 5.2%) than the other procedures (mean = 11.1%, SD = 9.3%; p < .001). Percentages were lower when the operating team included a senior surgeon (mean = 8.4%, standard deviation = 9.2%) than when it did not (mean = 10.1%, standard deviation = 6.9%; p < .001). CONCLUSION: Surgical intelligence revealed a substantial percentage of OOB segments in laparoscopic gynecological procedures, alongside associations with surgeon seniority and procedure type. Further research is needed to evaluate how laparoscope removal affects postoperative outcomes and operational efficiency in surgery.

A novel high accuracy model for automatic surgical workflow recognition using artificial intelligence in laparoscopic totally extraperitoneal inguinal hernia repair (TEP).

INTRODUCTION: Artificial intelligence and computer vision are revolutionizing the way we perceive video analysis in minimally invasive surgery. This emerging technology has increasingly been leveraged successfully for video segmentation, documentation, education, and formative assessment. New, sophisticated platforms allow pre-determined segments chosen by surgeons to be automatically presented without the need to review entire videos. This study aimed to validate and demonstrate the accuracy of the first reported AI-based computer vision algorithm that automatically recognizes surgical steps in videos of totally extraperitoneal (TEP) inguinal hernia repair. METHODS: Videos of TEP procedures were manually labeled by a team of annotators trained to identify and label surgical workflow according to six major steps. For bilateral hernias, an additional change of focus step was also included. The videos were then used to train a computer vision AI algorithm. Performance accuracy was assessed in comparison to the manual annotations. RESULTS: A total of 619 full-length TEP videos were analyzed: 371 were used to train the model, 93 for internal validation, and the remaining 155 as a test set to evaluate algorithm accuracy. The overall accuracy for the complete procedure was 88.8%. Per-step accuracy reached the highest value for the hernia sac reduction step (94.3%) and the lowest for the preperitoneal dissection step (72.2%). CONCLUSIONS: These results indicate that the novel AI model was able to provide fully automated video analysis with a high accuracy level. High-accuracy models leveraging AI to enable automation of surgical video analysis allow us to identify and monitor surgical performance, providing mathematical metrics that can be stored, evaluated, and compared. As such, the proposed model is capable of enabling data-driven insights to improve surgical quality and demonstrate best practices in TEP procedures.

Introducing surgical intelligence in gynecology: Automated identification of key steps in hysterectomy.

OBJECTIVE: The analysis of surgical videos using artificial intelligence holds great promise for the future of surgery by facilitating the development of surgical best practices, identifying key pitfalls, enhancing situational awareness, and disseminating that information via real-time, intraoperative decision-making. The objective of the present study was to examine the feasibility and accuracy of a novel computer vision algorithm for hysterectomy surgical step identification. METHODS: This was a retrospective study conducted on surgical videos of laparoscopic hysterectomies performed in 277 patients in five medical centers. We used a surgical intelligence platform (Theator Inc.) that employs advanced computer vision and AI technology to automatically capture video data during surgery, deidentify, and upload procedures to a secure cloud infrastructure. Videos were manually annotated with sequential steps of surgery by a team of annotation specialists. Subsequently, a computer vision system was trained to perform automated step detection in hysterectomy. Analyzing automated video annotations in comparison to manual human annotations was used to determine accuracy. RESULTS: The mean duration of the videos was 103 ± 43 min. Accuracy between AI-based predictions and manual human annotations was 93.1% on average. Accuracy was highest for the dissection and mobilization step (96.9%) and lowest for the adhesiolysis step (70.3%). CONCLUSION: The results of the present study demonstrate that a novel AI-based model achieves high accuracy for automated steps identification in hysterectomy. This lays the foundations for the next phase of AI, focused on real-time clinical decision support and prediction of outcome measures, to optimize surgeon workflow and elevate patient care.

Automated surgical step recognition in transurethral bladder tumor resection using artificial intelligence: transfer learning across surgical modalities.

Objective: Automated surgical step recognition (SSR) using AI has been a catalyst in the "digitization" of surgery. However, progress has been limited to laparoscopy, with relatively few SSR tools in endoscopic surgery. This study aimed to create a SSR model for transurethral resection of bladder tumors (TURBT), leveraging a novel application of transfer learning to reduce video dataset requirements. Materials and methods: Retrospective surgical videos of TURBT were manually annotated with the following steps of surgery: primary endoscopic evaluation, resection of bladder tumor, and surface coagulation. Manually annotated videos were then utilized to train a novel AI computer vision algorithm to perform automated video annotation of TURBT surgical video, utilizing a transfer-learning technique to pre-train on laparoscopic procedures. Accuracy of AI SSR was determined by comparison to human annotations as the reference standard. Results: A total of 300 full-length TURBT videos (median 23.96 min; IQR 14.13-41.31 min) were manually annotated with sequential steps of surgery. One hundred and seventy-nine videos served as a training dataset for algorithm development, 44 for internal validation, and 77 as a separate test cohort for evaluating algorithm accuracy. Overall accuracy of AI video analysis was 89.6%. Model accuracy was highest for the primary endoscopic evaluation step (98.2%) and lowest for the surface coagulation step (82.7%). Conclusion: We developed a fully automated computer vision algorithm for high-accuracy annotation of TURBT surgical videos. This represents the first application of transfer-learning from laparoscopy-based computer vision models into surgical endoscopy, demonstrating the promise of this approach in adapting to new procedure types.

Harmonic scalpel versus flexible CO2 laser for tongue resection: a histopathological analysis of thermal damage in human cadavers.

BACKGROUND: Monopolar cautery is the most commonly used surgical cutting and hemostatic tool for head and neck surgery. There are newer technologies that are being utilized with the goal of precise cutting, decreasing blood loss, reducing thermal damage, and allowing faster wound healing. Our study compares thermal damage caused by Harmonic scalpel and CO2 laser to cadaveric tongue. METHODS: Two fresh human cadaver heads were enrolled for the study. Oral tongue was exposed and incisions were made in the tongue akin to a tongue tumor resection using the harmonic scalpel and flexible C02 laser fiber at various settings recommended for surgery. The margins of resection were sampled, labeled, and sent for pathological analysis to assess depth of thermal damage calculated in millimeters. The pathologist was blinded to the surgical tool used. Control tongue tissue was also sent for comparison as a baseline for comparison. RESULTS: Three tongue samples were studied to assess depth of thermal damage by harmonic scalpel. The mean depth of thermal damage was 0.69 (range, 0.51 - 0.82). Five tongue samples were studied to assess depth of thermal damage by CO2 laser. The mean depth of thermal damage was 0.3 (range, 0.22 to 0.43). As expected, control samples showed 0 mm of thermal damage. There was a statistically significant difference between the depth of thermal injury to tongue resection margins by harmonic scalpel as compared to CO2 laser, (p = 0.003). CONCLUSION: In a cadaveric model, flexible CO2 laser fiber causes less depth of thermal damage when compared with harmonic scalpel at settings utilized in our study. However, the relevance of this information in terms of wound healing, hemostasis, safety, cost-effectiveness, and surgical outcomes needs to be further studied in clinical settings.

Impact of data on generalization of AI for surgical intelligence applications.

AI is becoming ubiquitous, revolutionizing many aspects of our lives. In surgery, it is still a promise. AI has the potential to improve surgeon performance and impact patient care, from post-operative debrief to real-time decision support. But, how much data is needed by an AI-based system to learn surgical context with high fidelity? To answer this question, we leveraged a large-scale, diverse, cholecystectomy video dataset. We assessed surgical workflow recognition and report a deep learning system, that not only detects surgical phases, but does so with high accuracy and is able to generalize to new settings and unseen medical centers. Our findings provide a solid foundation for translating AI applications from research to practice, ushering in a new era of surgical intelligence.

Magnetic resonance imaging showed no signs of overuse or permanent injury to the lumbar sacral spine during a Special Forces training course.

BACKGROUND CONTEXT: Special Forces training is even more demanding than that of elite athletes. The training includes grueling physical activity and periods of sleep deprivation. The soldiers routinely carry heavy loads up to 40% of their body weight on their backs while running and marching for distances up to 90 km. PURPOSE: Our purpose was to find out if Special Forces recruits are able to complete the preparatory Navy Seals training program without sustaining magnetic resonance imaging (MRI) signs of overuse or irreversible injury to their backs. STUDY DESIGN/SETTING: Prospective cohort study. We performed MRI scans before and after 14 weeks of Navy Seals preparatory training course. PATIENT SAMPLE: Ten soldiers underwent MRI of their lumbar sacral spines and right knees before and after the completion of Navy Seals preparatory training. OUTCOME MEASURES: Physiologic measures. Lumbar sacral spine and knee MRI tests were performed before and after the training to identify changes in the spinal discs, facet joints, pars interarticularis, vertebral bodies, knee articular cartilage, ligaments, knee menisci, and the presence or absence of soft tissue and/or bone edema. METHODS: We investigated the difference in spine and knee pathology before and after a 14-week Navy Seals preparatory training course by using MRI criteria. The recruits participating in the study were monitored for acute and overuse injuries every 3 to 4 weeks. RESULTS: Before the training, seven out of ten spine MRI scans were normal. Two showed small L5-S1 disc bulges, one of them with concomitant Scheuermann's disease. Another soldier's MRI showed L1-L4 mild Scheuermann's disease. Follow-up MRI showed no spinal changes. Before the training, one knee had a small lateral femoral condyle cartilage lesion. Nine of ten knees had prepatellar swelling, five had increased joint fluid, and two bone edema. Follow-up magnetic resonance imaging showed improvement in the prepatellar swelling in eight soldiers, no change in one soldier, and increased knee effusion and a new medial femoral condyle bone edema in another. The lateral femoral condyle lesion remained unchanged. CONCLUSIONS: According to MRI criteria, the soldiers in this study completed the 14-week training, which involved loading of their spines far beyond the levels recommended by the US National Institute for Occupational Safety and Health without sustaining irreversible damage to their spines or knees. Although the subjects' knees showed signs of overuse injury, their backs did not.

Evaluating new types of tourniquets by the Israeli Naval special warfare unit.

BACKGROUND: Extremity injuries, which accounts for 20% of all battlefield injuries, result in 7-9% of deaths during military activity. Silicone tourniquets were used, by the Israeli Defense Force (IDF) soldiers, for upper extremity and calf injuries, while thigh injuries were treated by an improvised "Russian" tourniquet (IRT). This is the first study, performed in the IDF, comparing the IRT with Combat Application Tourniquets (CAT) and Special Operations Force Tactical Tourniquets (SOFTT). 23 operators from the Israeli Naval Unit (Shayetet 13) were divided into two groups according to their medical training (11 operators trained as first-responders; 12 operators as medics). Repetitive applications of the three tourniquets over the thigh and upper arm, and self-application of the CAT and SOFTT over the dominant extremity were performed using dry and wet tourniquets (828 individual placements) with efficacy recorded. Cessation of distal arterial flow (palpation; Doppler ultrasound) confirmed success, while failure was considered in the advent of arterial flow or tourniquet instability. Satisfaction questionnaires were filled by the operators. RESULTS: CAT and SOFTT were found to be superior to the IRT, in occluding arterial blood flow to the extremities (22%, 23% and 38%, respectively, failure rate). The application was quicker for the CAT and SOFTT as compared to the IRT (18, 26, 52 seconds, respectively). Wet tourniquets neither prolonged application nor did they increase failure rates. Similarly, medics didn't have any advantage over non-medic operators. No findings indicated superiority of CAT and SOFTT over one another, despite operators' preference of CAT. CONCLUSIONS: CAT and SOFTT offer an effective alternative to the IRT in stopping blood flow to extremities. No difference was observed between medics and non-medic operators. Thus, the CAT was elected as the preferred tourniquet by our unit and it is being used by all the operators.

Use of novel nonfluoroscopic three-dimensional electroanatomic mapping system to monitor and analyze heart surgery in animal models.

BACKGROUND: The new method of three-dimensional (3D) electroanatomic mapping was presented as an important tool for cardiac imaging and intervention. We present herein the first use of this technology for the monitoring, analysis, and development of cardiac surgery at the preclinical stage. METHODS: The method is based on utilizing a locatable catheter connected to an endocardial mapping and navigating system, to accurately establish the location and orientation of the tip of the mapping catheter and simultaneously record its local electrogram. The 3D geometry of the beating cardiac chamber is reconstructed in real time. The system was tested on six goats that underwent dynamic cardiomyoplasty. Two maps of each animal were performed: preoperative and postoperative during the stimulation protocol of the skeletal muscle. RESULTS: The electroanatomic mapping system provided detailed maps of the left ventricle during the stimulation protocol, which demonstrated a striking geometric difference between the assisted and the unassisted beats. These geometric changes are best described by referring to left ventricular long-axis movements (22.3 +/- 3.8 degrees vs 3.4 +/- 1.6 degrees, p < 0.001), center-of-mass movements (10.4 +/- 3.0 mm vs 3.9 +/- 1.6 mm, p < 0.005), and the changes in upward movement viewed along the base (7.9 +/- 1.9 mm vs 3.6 +/- 1.7 mm, p < 0.01), middle (13.8 +/- 4.0 mm vs 7.3 +/- 1.8 mm, p < 0.005), and the apex of the heart (28.1 +/- 4.5 vs 5.3 +/- 2.3 mm, p < 0.001) [mean +/- SD]. CONCLUSIONS: The 3D electroanatomic mapping system allows detailed reconstruction of the left ventricular geometry and a clear view of the difference between the assisted and the unassisted beats. This novel monitoring system may serve as an important tool for the analysis and development of new techniques in cardiac surgery.

Hemodynamic analysis of descending versus ascending aortomyoplasty, and comparison with intra-aortic balloon pump.

OBJECTIVE: Descending and ascending aortomyoplasty are two surgical procedures intended to induce hemodynamic benefits similar to those of the intra-aortic-balloon-pump (IABP). To date, there have been no studies comparing the two surgical techniques. The objective of this study was to compare coronary blood flow augmentation and afterload reduction as produced by descending and ascending aortomyoplasty counterpulsation METHODS: Twenty-two mongrel dogs (18-35 kg) underwent IABP application (n=7), descending (n=8), or ascending (n=7) aortomyoplasty. Left anterior descending (LAD) coronary artery blood flow was measured using a Transonic Doppler flow probe. Left ventricular pressure as well as aortic pressures proximal and distal to either the aortomyoplasty site or the IABP position were monitored continuously. RESULTS: Descending aortomyoplasty induced higher elevation in the LAD blood flow during assisted beats (27% from 10.8+/-4 to 13.8+/-6 ml/min, P<0.001) than that induced by either ascending aortomyoplasty (19% from 11.7+/-5 to 14+/-5 ml/min, P<0.001) or IABP counterpulsation (18% from 8.6+/-3 to 10.2+/-4 ml/min, P<0.001). Conversely, while ascending aortomyoplasty reduced the left ventricular end-diastolic pressure by 16% (from 60+/-18 to 50+/-22 mmHg, P<0.001), similar to the 16% after load reduction achieved by the IABP counterpulsation, descending aortomyoplasty failed to induce afterload reduction. CONCLUSIONS: Descending aortomyoplasty produces higher coronary blood flow augmentation than either ascending aortomyoplasty or IABP. However, afterload reduction comparable to that achieved by IABP was observed only with ascending aortomyoplasty and not with descending aortomyoplasty.

[Difficulties in diagnosis and localization of recurrent medullary thyroid carcinoma].

Recurrent and residual medullary thyroid carcinoma (MTC) are common in patients following primary surgical resection. Difficulty arises in performing precise localization of the tumor because of anatomical distortion of the neck structures following surgery. To date, no modality has been shown superior to others in the diagnosis of recurrent or residual MTC, and the issue is currently under debate in the literature. We report a case in which secondary recurrence of MTC was detected and localized using a novel combination of preoperative and intraoperative radionuclide imaging, and a method of preventing intraoperative damage to the recurrent laryngeal nerve in the anatomically disrupted neck. To our knowledge, this is the first report of a combination of these three modalities in detection and localization of recurrent MTC, while minimizing the possibility for nerve injury during the operative procedure. Such a therapeutic strategy may prove useful in the management of patients who have previously undergone neck surgery and suffer from anatomical distortion of normal neck structures.

Application of a flexible CO(2) laser fiber for neurosurgery: laser-tissue interactions.

OBJECT: The CO(2) laser has an excellent profile for use in neurosurgery. Its high absorption in water results in low thermal spread, sparing adjacent tissue. Use of this laser has been limited to line-of-sight applications because no solid fiber optic cables could transmit its wavelength. Flexible photonic bandgap fiber technology enables delivery of CO(2) laser energy through a flexible fiber easily manipulated in a handheld device. The authors examined and compared the first use of this CO(2) laser fiber to conventional methods for incising neural tissue. METHODS: Carbon dioxide laser energy was delivered in pulsed or continuous wave settings for different power settings, exposure times, and distances to cortical tissue of 6 anesthetized swine. Effects of CO(2) energy on the tissue were compared with bipolar cautery using a standard pial incision technique, and with scalpel incisions without cautery. Tissue was processed for histological analysis (using H & E, silver staining, and glial fibrillary acidic protein immunohistochemistry) and scanning electron microscopy, and lesion measurements were made. RESULTS: Light microscopy and scanning electron microscopy revealed laser incisions of consistent shape, with central craters surrounded by limited zones of desiccated and edematous tissue. Increased laser power resulted in deeper but not significantly wider incisions. Bipolar cautery lesions showed desiccated and edematous zones but did not incise the pia, and width increased more than depth with higher power. Incisions made without using cautery produced hemorrhage but minimal adjacent tissue damage. CONCLUSIONS: The photonic bandgap fiber CO(2) laser produced reliable cortical incisions, adjustable over a range of settings, with minimal adjacent thermal tissue damage. Ease of application under the microscope suggests this laser system has reached true practicality for neurosurgery.

Temporal changes in the endocardial ST segment during the evolution of myocardial infarction in dogs.

Acute coronary occlusion causes ST-segment elevation on the body surface ECG and on the epicardial electrogram in the territory supplied by that artery. The occurrence and significance of endocardial ST changes have not been studied. The NOGA electromechanical mapping was performed on eight anesthetized dogs at baseline, immediately after occlusion of the LAD, and again at 5 hours to assess regional changes in the ST segment. At 3 days and 4 weeks the ventricles were remapped for comparison. Regional unipolar ST-segment elevation was measured for each zone from NOGA maps at 0, 80, and 120 ms after the J point. ST segments rose immediately in the infarct zones, as demarcated by echocardiography, compared to remote zones, but by 3 days had dropped below, and at 4 weeks returned to baseline values. Immediately postocclusion, ST elevation at 120 ms best differentiated between normal versus abnormal echo scores (concordance = 0.80), probably by correcting for pressure induced ST elevation. In conclusion, acute endocardial ST-segment changes occur in the infarct zone in the dog, showing a distinctive temporal evolution.

Technical delivery of myogenic cells through an endocardial injection catheter for myocardial cell implantation.

BACKGROUND: The next clinical frontier in the therapeutics of ischemic heart disease may involve the development and delivery of specific molecules and cells into the myocardium. The aim of the present study was to evaluate the efficiency and safety of the MyoStar injection catheter (Biosense-Webster Inc.) that has recently been developed to deliver molecules and cells to the myocardium. The 8 Fr (110 cm length) catheter comprises a navigation sensor with a 27 gauge needle at the distal tip. METHODS: Mouse myogenic cells (C2) were delivered to a tissue culture dish through different modalities: a standard laboratory pipette, a syringe needle (27 gauge) and the injection catheter. The cells were counted and monitored for growth and differentiation in the tissue culture immediately after delivery and two, three and six days later. Cells that were injected through a regular syringe needle or through the injection catheter demonstrated the same capacity to proliferate in tissue culture up to six days. RESULTS: The behavior of the cells in culture (fusion) was identical for the cells delivered to the tissue culture by a pipette or by the injection catheter. CONCLUSION: The results of the present study indicate that delivery of cells through the MyoStar injection catheter is a method with no significant loss or adverse effects to the cells along the path of the catheter. The catheter, which possesses both injection and navigation capabilities, can be used to deliver cell therapy to patients with ischemic heart disease.

Strict thermoregulation attenuates myocardial injury during coronary artery bypass graft surgery as reflected by reduced levels of cardiac-specific troponin I.

We assessed the cardioprotective effects of perioperative maintenance of normothermia by determining the perioperative profile of troponin I, a highly cardiac-specific protein important in risk stratification of patients with acute ischemic events. Candidates for their primary coronary artery bypass grafting (CABG) were randomized into a new thermoregulation system group, Allon( thermoregulation (AT; n = 30), and a routine thermal care (RTC; n = 30) group. Anesthetic and operative techniques were similar in both groups. Intraoperative warming was applied before and after cardiopulmonary bypass (CPB) and up to 4 h after surgery. Perioperative temperature and hemodynamic data were recorded. Blood samples for creatine kinase (CK) and its isoform, MB (CK-MB), and for cardiac-specific troponin I (cTnI) were obtained at predetermined intervals throughout the entire operation. Core and skin temperatures were higher in the AT group at all time points. The systemic vascular resistance was lower and the cardiac index higher in the AT group at all intra- and postoperative time points. Increases in CK, CK-MB, and cTnI levels indicated intraoperative ischemic insult in all patients. The respective CK levels for the AT and RTC groups were 53.3 +/- 22.7 IU/L and 47.9 +/- 17.86 IU/L at the time of anesthesia and 64.7 +/- 45.6 IU/L and 47.8 +/- 19.4 IU/L 30 min after the onset of surgery, demonstrating thereafter a steep increase before the discontinuation of CPB. CK-MB mass concentrations in both groups behaved almost identically. Pre-CPB cTnI levels at anesthesia induction were 0.3 +/- 0 ng/mL in both groups, followed by a distinctive profile observed after separation from CPB: 28.1 +/- 11.4 ng/mL, 26.05 +/- 9.20 ng/mL, and 22.3 +/- 8.9 ng/mL at discontinuation from CPB, chest closure, and 2 h after surgery, respectively, in the RTC group, versus 0.6 +/- 4.6 ng/mL, 6.6 +/- 5.5 ng/mL, and 7.9 +/- 4.76 ng/mL at these three time points, respectively, in the AT group (P < 0.01 between groups at the specified time points). Contrary to conventional thinking about the benefits of hypothermia, maintenance of normothermia throughout the non-CPB phases during CABG was demonstrated to be important in attenuating myocardial ischemic injury. Insofar as troponin I was more sensitive than other tested markers, it may provide important data on possible protection from myocardial insult and on other cardioprotective measures.