Comparison of the effects of axillary brachial plexus block, inhalation anesthesia, and total intravenous anesthesia on tourniquet-induced ischemia-reperfusion injury in upper extremity surgery.

BACKGROUND: Post-ischemia reperfusion can lead to oxidative stress and an increase in oxidative markers. Employing preventive strategies and antioxidant agents may help mitigate ischemia-reperfusion injury (IRI). The use of a tourniquet in extremity surgery has been associated with IRI. This study aims to investigate the impact of three different approaches- brachial plexus block, total intravenous anesthesia (TIVA), and inhalation anesthesia-on IRI during upper extremity surgery using a tourniquet. METHODS: Patients aged 18 to 45 with American Society of Anesthesiologists (ASA) I-II scores were randomly assigned to one of three groups: Group A received an axillary block with bupivacaine; Group I underwent inhalation anesthesia with sevoflurane; and Group T received TIVA with propofol and remifentanil infusion. Blood samples were collected to measure glucose, lactate, total anti-oxidant status (TAS), total oxidant status (TOS), and ischemia-modified albumin (IMA) levels at various time points: before anesthesia (t1), 1 minute before tourniquet release (t2), 20 minutes after tourniquet release (t3), and 4 hours after tourniquet release (t4). RESULTS: In Group I, lactate levels at t3, and glucose levels at t2 and t3, were higher compared to the other groups. Group A exhibited lower IMA levels at t2, t3, and t4 than the other groups. Additionally, Group I had lower IMA levels at t2, t3, and t4 compared to Group T. TAS levels were higher in Group I at t2, t3, and t4 compared to the other groups. TOS levels at t2 and t3 were lower in Group A than in Group I. CONCLUSION: Axillary anesthesia results in a sympathetic block, promoting better perfusion of the upper extremity. This study demonstrated lower levels of oxidative stress markers with axillary plexus block. Therefore, these results suggest that the axillary block has the potential to mitigate IRI.

Randomised controlled trial of tourniquet associated pain generated in lower limb after exsanguination by Esmarch bandage versus limb elevation.

BACKGROUND: Tourniquets are common adjuncts in the operating theatre but can be associated with post-operative pain. This study was designed to compare what effect pre-tourniquet Esmarch bandage exsanguination has on pain, compared to pre-tourniquet exsanguination by elevation alone. METHODS: 52 volunteers (104 lower limbs) were included in this study with each volunteer acting as their own matched control. The primary outcome was patient reported pain, measured in both legs simultaneously using area under curve. Secondary outcomes were pain score during inflation and deflation, cumulative pain score, duration of recovery and blood pressure during testing. RESULTS: Pain after Esmarch was superior to elevation as measured by area under pain curve (68.9 SD 26.1 vs 77.2 SD 27.3, p = 0.0010), independent of leg dominance. Cumulative pain scores demonstrated the same superiority after inflation (50.7 SD 17.1 vs 52.9 SD 17.0, p = 0.026) but not after deflation (p = 0.59). Blood pressure was not significantly different. Time to full recovery of the lower limb was the same for both groups-7.6 min (SD 2.1 min, p = 0.80). CONCLUSION: Previous studies describe a positive effect on pain when Esmarch bandage was used prior to tourniquet inflation for upper limb. Our findings suggest the same benefit from Esmarch when it was used on lower limbs-particularly during inflation of tourniquet. In addition to pain profiles, surgeon preference and patient factors need to be considered when deciding between elevation and Esmarch bandage.

New Frontiers in Wide-Awake Surgery.

LEARNING OBJECTIVES: After studying this article, the participant should be able to: 1. Explain the most important benefits of wide-awake surgery to patients. 2. Tumesce large parts of the body with minimal pain local anesthesia injection technique to eliminate the need for sedation for many operations. 3. Apply tourniquet-free surgery to upper and lower limb operations to avoid the sedation required to tolerate tourniquet pain. 4. Move many procedures out of the main operating room to minor procedure rooms with no increase in infection rates to decrease unnecessary cost and solid waste in surgery. SUMMARY: Three disruptive innovations are changing the landscape of surgery: (1) minimally painful injection of large-volume, low-concentration tumescent local anesthesia eliminates the need for sedation for many procedures over the entire body; (2) epinephrine vasoconstriction in tumescent local anesthesia is a good alternative to the tourniquet and proximal nerve blocks in extremity surgery (sedation for tourniquet pain is no longer required for many procedures); and (3) evidence-based sterility and the elimination of sedation enable many larger procedures to move out of the main operating room into minor procedure rooms with no increase in infection rates. This continuing medical education article explores some of the new frontiers in which these changes affect surgery all over the body.

COMBAT-C: COntrol of Major Bleeding by Application of Tourniquets over Clothing.

INTRODUCTION: External bleeding is the leading cause of preventable trauma-related death. In certain circumstances, tourniquet application over clothing may be necessary. Therefore, the aim of this study was to assess the effectiveness of tourniquets over different clothing setups. METHODS: Three windlass tourniquets (CAT, SAMXT, SOFTT-W) were applied over nine different clothing setups and without clothing on the Hapmed™ Tourniquet Trainer. We compared each tourniquet in each clothing setup to the tourniquet trainer that was not dressed, and we compared the three tourniquets within each clothing setup concerning blood loss, applied pressure and application time. Regression analysis of the effect of thickness, mean weight, mean deformation, application time, and applied pressure on blood loss was performed. RESULTS: Although blood loss was significantly greater in the CAT and SAMXT tourniquets when they were applied over leather motorcycle trousers, the overall findings showed that the clothing setups significantly reduced or did not affect blood loss. The mean blood loss was the lowest with CAT and the highest with SOFTT-W. The measured mean pressures were lower than 180 mmHg in four out of nine clothing setups with SOFTT-W, but CAT and SAMXT always exceeded this threshold. CAT had the fastest application time. Blood loss was significantly influenced by applied pressure and application time but was influenced to a far lesser degree by clothing parameters. CONCLUSION: The effects of the clothing setups were of little clinical relevance, except for leather motorcycle trousers. The effects of rugged protective equipment, e.g., hazard suits, are conceivable and need to be tested for specific garments with the tourniquet intended for use. No clothing parameter for predicting tourniquet effectiveness could be identified.

SAFE USE OF INTRA-OPERATIVE TOURNIQUETS IN A DISTRICT HOSPITAL IN THE UK-AN AUDIT STUDY IN ORTHOPAEDIC THEATRES AND REVIEW OF CURRENT LITERATURE.

The use of tourniquet is common in orthopaedic surgeries as it reduces blood loss, enhances visualization of the operating field, and leads to quicker procedures. However, the use of tourniquet has certain risks which can be avoided by following guidelines like British Orthopaedic Association Standards for Trauma (BOAST) guidelines for safe use of tourniquet. This audit study was done in a District general hospital to check the compliance of two trauma theatres with BOAST guidelines. The audit found that there was poor documentation of tourniquet details in the operation notes (10%). Regarding tourniquet time and pressure, the compliance in the two theatres was 95 % & 97.5 %. The recommendations of this audit were to use a template to improve documentation of tourniquet details in the operation notes and training of theatre staff on BOAST guidelines for safe use of tourniquet.

Tranexamic Acid and Tourniquet: Which Combination Reduces Blood Loss Most Effectively?

BACKGROUND: Blood loss during and after total knee arthroplasty (TKA) can lead to substantial morbidity and the need for blood transfusions. There are several methods to minimize blood loss and decrease transfusion rates in patients undergoing TKA. Tranexamic acid, an antifibrinolytic agent with known efficacy for achieving these goals, is combined with tourniquets to reduce bleeding in arthroplasty surgeries. Our study investigated the effects of various combinations of tranexamic acid and tourniquet use on bleeding in knee arthroplasty in 558 patients. AIM: We aimed to determine the method that would provide the least blood loss and transfusion need in knee arthroplasty surgery. METHODS: Between January 2018 and December 2022, 558 patients aged between 55 and 85 years underwent TKA surgery for grade 4 gonarthrosis in our clinic, and their decrease in hemoglobin value and whether they were transfused or not were analyzed. The patients were divided into four groups based on use of tranexamic acid and tourniquet. Demographic variables and patient data (body mass index, INR values, and preoperative hemoglobin values) were recorded. RESULTS: There were 558 patients with a mean age of 68.19 (67 ± 6.949) years. In group 1, tranexamic acid was not used in 128 patients and tourniquet was used only during cementation; in group 2, in 132 patients, tranexamic acid was not used and tourniquet was used throughout the surgery; in group 3, in 158 patients, tranexamic acid was used and tourniquet was used throughout the surgery; in group 4, in 140 patients, tranexamic acid was used and tourniquet was used only during cementation. The decrease in hemoglobin value and transfusion rate was lowest in group 3 and highest in group 1. Besides, there was a greater decrease in hemoglobin value in group 2 than in group 4 and the transfusion rate was similar. CONCLUSIONS: This clinical study showed that using tranexamic acid and a tourniquet throughout surgery significantly reduced the decrease in hemoglobin value and the need for transfusion.

Opportunity for a Community Health Fair Model of Bleeding Control Training.

BACKGROUND: Traumatic hemorrhage is a prevalent cause of death nationally, with >50% of civilian deaths estimated to be preventable with more timely intervention. This study investigated the efficacy of training large and diverse audiences in bleeding control methods including tourniquets in community health fair settings. METHODS: A booth was utilized for bleeding control training at community health fairs via direct demonstrations of pressure, wound packing, and commercial and improvised tourniquet application followed by hands-on practice. Participants self-rated their perceived abilities while instructors rated the participant competency. RESULTS: 117 community members participated during two fairs, though not every person completed every portion of the training. Average age was 33 (range 6-82) and the majority were female (65.0%). There was no difference in self-perceived skill compared to trainer grading of participant's ability to identify life-threatening bleeding (112 (97.4%) vs 106 (97.2%); P = 1), apply pressure (113 (98.3%) vs 106 (97.2%); P = .68), and pack a wound (102 (88.7%) vs 92 (84.4%); P = .43). No difference in difficulty was noted in placing commercial vs improvised tourniquets (16 (43%) vs 14 (45%); P = .87). However, participants were overconfident in their ability to place tourniquets compared to trainer grading, respectively (112 (98.2%) vs 100 (91.7%; P = .03)). DISCUSSION: Community fair classes provide opportunities to train large and diverse audiences in bleeding control techniques. However, participants overestimated their ability to appropriately apply tourniquets. Further investigation is needed into best educational approaches to optimize the impact of bleeding control kits that have been distributed in multiple states.

Is Tourniquet Pain the Result of Increased Compartment Pressure in the Forearm?

ABSTRACT: The pneumatic tourniquet has been a mainstay in upper extremity surgery by allowing the surgeon to operate in a blood-free field. Many upper extremity surgical procedures are done under local anesthesia or minimal sedation, and the problem of tourniquet pain is a vexing one. The question is posed: Is tourniquet pain the result of increased compartment pressure in the forearm? This study measured compartment pressures of the volar forearm in 10 healthy normotensive volunteers before inflation of a pneumatic tourniquet and compared it with pressure measurements taken while the tourniquet was still inflated after 15 minutes. Compartment pressures were measured using a Stryker needle manometer; all measurements were taken in the volar forearm by the senior author (C.H.M.). There was no increase in the volar/flexor compartment pressure of the forearm after 15 minutes of tourniquet inflation. All subjects complained of pain of the forearm, characteristically what is commonly called "tourniquet pain." We therefore conclude that in the upper extremity, at least for relatively short operating times, appropriate inflation of a tourniquet does not induce the early onset of increased compartment pressure in the forearm.

Cubital tunnel release with Wide Awake Local Anaesthesia No Tourniquet (WALANT) technique in an outpatient setting is safe and effective.

Ulnar nerve release is often performed under general anaesthesia. Wide Awake Local Anaesthesia No Tourniquet (WALANT) is a new anaesthetic method increasingly used by hand surgeons in an outpatient setting. It has advantages such as the possibility to shift surgical interventions out of the regular surgical theatre settings into an outpatient clinical setting, no risk of complications or side effects resulting from regional and general anesthesia and decreased costs. The use of WALANT has not been investigated extensively in elbow surgery. This study aims to evaluate clinical outcomes after ulnar nerve release under WALANT 27 patients with ulnar nerve release for cubital tunnel syndrome were included. The primary outcome was the presence of (remaining) symptoms after ulnar nerve release. Data was extracted from medical records. 13 out of 27 patients had (mild) remaining symptoms after ulnar nerve release, and 1 complication (superficial wound infection) was seen. Ulnar nerve release under WALANT is safe and effective in patients with primary ulnar nerve entrapment that have failed conservative therapy.

A low-cost, DIY tourniquet simulator with built-in self-assessment for prehospital providers in Guatemala city.

BACKGROUND: Hemorrhage is the leading cause of preventable death after trauma. In high-income countries first responders are trained in hemorrhage control techniques but this is not the case for developing countries like Guatemala. We present a low-cost training model for tourniquet application using a combination of virtual and physical components. METHODS: The training program includes a mobile application with didactic materials, videos and a gamified virtual reality environment for learning. Additionally, a physical training model of a bleeding lower extremity is developed allowing learners to practice tourniquet application using inexpensive and accessible materials. Validation of the simulator occurred through content and construct validation. Content validation involved subjective assessments by novices and experts, construct validation compared pre-training novices with experts. Training validation compared pre and post training novices for improvement. RESULTS: Our findings indicate that users found the simulator useful, realistic, and satisfactory. We found significant differences in tourniquet application skills between pre-training novices and experts. When comparing pre- and post-training novices, we found a significantly lower bleeding control time between the groups. CONCLUSION: This study suggests that this training approach can enhance access to life-saving skills for prehospital personnel. The inclusion of self-assessment components enables self-regulated learning and reduces the need for continuous instructor presence. Future improvements involve refining the tourniquet model, validating it with first-responder end users, and expanding the training program to include other skills.

It's time to regulate - The importance of accurate surgical-grade tourniquet autoregulation in blood flow restriction exercise applications.

OBJECTIVE: Evaluate the efficacy of five common blood flow restriction (BFR) systems to accurately maintain and autoregulate BFR pressure in the tourniquet cuff near target pressure throughout exercise. DESIGN: Randomised crossover design. SETTING: Laboratory. PARTICIPANTS: 15 healthy individuals. OUTCOME MEASURES: 1) Percentage of total BFR time that surgical-grade tourniquet autoregulation, defined as automatic and rapid self-regulation of cuff pressure to within ±15 mmHg of initial target pressure within 1 s in the presence of transient pressure changes associated with exercise, was provided; 2) pressure change in the BFR cuff throughout exercise, by comparing the initial target pressure to the measured pressure at completion of BFR exercise. RESULTS: One BFR system could provide surgical-grade tourniquet autoregulation for the whole duration (100 ± 0%) of the BFR exercise in all subjects. In two of the five BFR systems evaluated, measured cuff pressure at the end of exercise was not different (p < 0.05) to the initial target pressure. CONCLUSIONS: Surgical-grade tourniquet autoregulation is important to consistently and reliably apply a targeted BFR pressure stimulus. This may allow BFR methodology and protocols to be accurately implemented and controlled so that the results can be more meaningfully compared, leading to the potential optimization of applications.

Effectiveness and safety of tourniquet utilization for civilian vascular extremity trauma in the pre-hospital settings: a systematic review and meta-analysis.

BACKGROUND: Tourniquets (TQ) have been increasingly adopted in pre-hospital settings recently. This study examined the effectiveness and safety of applying TQ in the pre-hospital settings for civilian patients with traumatic vascular injuries to the extremities. MATERIALS AND METHODS: We systematically searched the Ovid Embase, PubMed, and Cochrane Central Register of Controlled Trials databases from their inception to June 2023. We compared pre-hospital TQ (PH-TQ) use to no PH-TQ, defined as a TQ applied after hospital arrival or no TQ use at all, for civilian vascular extremity trauma patients. The primary outcome was overall mortality rate, and the secondary outcomes were blood product use and hospital stay. We analyzed TQ-related complications as safety outcomes. We tried to include randomized controlled trials (RCTs) and non-randomized studies (including non-RCTs, interrupted time series, controlled before-and-after studies, cohort studies, and case-control studies), if available. Pooled odds ratios (ORs) were calculated and the certainty of evidence was assessed using Grading of Recommendations Assessment, Development, and Evaluation (GRADE) methodology. RESULTS: Seven studies involving 4,095 patients were included. In the primary outcome, pre-hospital TQ (PH-TQ) use significantly decrease mortality rate in patients with extremity trauma (odds ratio [OR], 0.48, 95% confidence interval [CI] 0.27-0.86, I2 = 47%). Moreover, the use of PH-TQ showed the decreasing trend of utilization of blood products, such as packed red blood cells (mean difference [MD]: -2.1 [unit], 95% CI: -5.0 to 0.8, I2 = 99%) or fresh frozen plasma (MD: -1.0 [unit], 95% CI: -4.0 to 2.0, I2 = 98%); however, both are not statistically significant. No significant differences were observed in the lengths of hospital and intensive care unit stays. For the safety outcomes, PH-TQ use did not significantly increase risk of amputation (OR: 0.85, 95% CI: 0.43 to 1.68, I2 = 60%) or compartment syndrome (OR: 0.94, 95% CI: 0.37 to 2.35, I2 = 0%). The certainty of the evidence was very low across all outcomes. CONCLUSION: The current data suggest that, in the pre-hospital settings, PH-TQ use for civilian patients with vascular traumatic injury of the extremities decreased mortality and tended to decrease blood transfusions. This did not increase the risk of amputation or compartment syndrome significantly.

Implementing Tourniquet Conversion Guidelines for Civilian EMS and Prehospital Organizations : A Case Report and Review.

Since the first documented use of a tourniquet in 1674, the popularity of tourniquets has waxed and waned. During recent wars and more recently in Emergency Medical Services systems, the tourniquet has been proven to be a valuable tool in the treatment of life-threatening hemorrhage. However, tourniquet use is not without risk, and several studies have demonstrated adverse events and morbidity associated with tourniquet use in the prehospital setting, particularly when left in place for more than 2 h. Consequently, the US military's Committee on Tactical Combat Casualty Care has recommended guidelines for prehospital tourniquet conversion to reduce the risk of adverse events associated with tourniquets once the initial hemorrhage has been controlled. Emergency Medical Services systems that operate in rural, frontier, and austere environments, especially those with transport times to definitive care that routinely exceed 2 h, may consider implementing similar tourniquet conversion guidelines.

Prospective Analysis of Simulated Pneumatic Tourniquet Use and Oedema Following Axillary Lymph Node Dissection.

Background: Tourniquet use during upper extremity surgery in patients with a history of axillary lymph node dissection (ALND) remains controversial due to the perceived but unproven risk of lymphoedema. We prospectively evaluated upper extremity swelling in patients with a history of unilateral ALND using a standardised tourniquet model. Methods: A tourniquet was applied to the upper arm bilaterally, with the unaffected side serving as an internal control. Each arm was subsequently held in an elevated position to reduce swelling. Hand volume was measured using an aqueous volumeter. Results: The patients' ALND arms experienced slightly greater increases in volume following tourniquet application compared to their healthy control arms. However, this amount of oedema was temporary and reversible, as both arms experienced spontaneous resolution of swelling with no significant difference in residual hand volume at the conclusion of the study. Conclusions: Tourniquet use may be safe in patients with a history of ALND. Further investigation is needed to verify this in a surgical setting. Level of Evidence: Level II (Therapeutic).

Lower limb blood flow occlusion increases systemic pressor response without increasing brachial arterial blood flow redistribution in women.

This study was conducted to investigate the systemic hemodynamic and vascular changes in women during and after two commonly used clinical blood flow restriction (BFR) pressures at rest. There are minimal data regarding the independent effects of BFR on hemodynamic and systemic vascular changes due to pressor response, particularly among women. Therefore, this study investigated BFR-induced alterations in pressor response and systemic flow redistribution at rest during two commonly used pressures (50% and 80% limb occlusion pressure [LOP]). Fifteen women (22.1 ± 4.2 years) completed two randomised sessions involving 8-min of bilateral, lower limb restriction at 50% or 80% LOP followed by 8-min of recovery post-deflation. Changes in vascular (arterial diameter [DIA], time-averaged mean velocity [TAMV], volume flow [VF], and area) and hemodynamic (heart rate [HR] and blood pressure) measures over time (pre-, during, post-occlusion) and by session (50% vs. 80% LOP) were tested using repeated measures analysis of variance. Repeated measures correlations (rrm) quantified common intraindividual associations between BFR-induced hemodynamic and vascular responses. HR increased from baseline during 50% LOP and remained elevated during recovery (p < 0.05). HR increased from baseline during 80% LOP, while tibial VF and TAMV decreased (p < 0.03 for all). HR and TAMV values returned to baseline during recovery, while brachial artery VF decreased (p < 0.05). Changes in HR, brachial VF, and brachial TAMV were similar between 50% and 80% LOP (rrm = 0.32-0.70, p < 0.05 for all). At 80% LOP, changes in HR were positively correlated with brachial VF (rrm = 0.38) and TAMV (rrm = 0.43) and negatively correlated with tibial VF (rrm = -0.36) and TAMV (rrm = -0.30) (p < 0.05 for all). Results suggest that BFR at 80% LOP elicits an acute systemic pressor reflex without concomitant increases in brachial arterial flow, while 50% LOP elicits a subdued response.

Aquatic Feasibility of Limbs Application of Tourniquets (AFLAT) during a Lifeguard Water Rescue: A Simulation Pilot Study.

INTRODUCTION: Control of massive hemorrhage (MH) is a life-saving intervention. The use of tourniquets has been studied in prehospital and battlefield settings but not in aquatic environments. OBJECTIVE: The aim of this research is to assess the control of MH in an aquatic environment by analyzing the usability of two tourniquet models with different adjustment mechanisms: windlass rod versus ratchet. METHODOLOGY: A pilot simulation study was conducted using a randomized crossover design to assess the control of MH resulting from an upper extremity arterial perforation in an aquatic setting. A sample of 24 trained lifeguards performed two randomized tests: one using a windlass-based Combat Application Tourniquet 7 Gen (T-CAT) and the other using a ratchet-based OMNA Marine Tourniquet (T-OMNA) specifically designed for aquatic use on a training arm for hemorrhage control. The tests were conducted after swimming an approximate distance of 100 meters and the tourniquets were applied while in the water. The following parameters were recorded: time of rescue (rescue phases and tourniquet application), perceived fatigue, and technical actions related to tourniquet skills. RESULTS: With the T-OMNA, 46% of the lifeguards successfully stopped the MH compared to 21% with the T-CAT (P = .015). The approach swim time was 135 seconds with the T-OMNA and 131 seconds with the T-CAT (P = .42). The total time (swim time plus tourniquet placement) was 174 seconds with the T-OMNA and 177 seconds with the T-CAT (P = .55). The adjustment time (from securing the Velcro to completing the manipulation of the windlass or ratchet) for the T-OMNA was faster than with the T-CAT (six seconds versus 19 seconds; P < .001; effect size [ES] = 0.83). The perceived fatigue was high, with a score of seven out of ten in both tests (P = .46). CONCLUSIONS: Lifeguards in this study demonstrated the ability to use both tourniquets during aquatic rescues under conditions of fatigue. The tourniquet with the ratcheting-fixation system controlled hemorrhage in less time than the windlass rod-based tourniquet, although achieving complete bleeding control had a low success rate.

Evaluating time until ligation in a novel tourniquet - A crossover randomized-controlled trial.

INTRODUCTION AND AIM: Severe external hemorrhage is a significant reason for morbidity and mortality in adults; thus, the swift and correct application of a tourniquet by laypersons can be lifesaving. We conducted this randomized-controlled cross-over study to investigate the use of a novel tourniquet. METHODS: Participants were recruited at the Heidelberg University Hospital. Eligible participants were ≥ 18 years old with a medical background but without prior experience in applying a tourniquet. Participants were 1:1 randomized to the intervention group (PAX tourniquet) or the control group (SAM or CAT tourniquet). In the control group, participants underwent another randomization to either the SAM or CAT tourniquet without a predefined allocation ratio. Hyperspectral measurements were undertaken (i) before ligation, (ii) 30 s after ligation, and (iii) 30 s after the reopening of the tourniquet. The primary outcome was time until ligation before crossover between the respective groups. The analysis of secondary endpoints included all attempts to assess a possible learning effect, intraoperator variability, and hyperspectral measurements. Participants were crossed to the other study group after a brief wash-out phase. RESULTS: In total, 50 participants were recruited, resulting in 100 attempts. A success rate of 98% was observed across the study population. Time until ligation was 49 s and 56 s (p = 0.572) in the intervention and control group, respectively. However, there was a significant difference between the PAX and SAM (54 vs 75 s; p = 0.037) and the SAM and CAT tourniquet (75 vs. 47 s; p = 0.015). Further, we observed a significant learning effect in participants allocated to the control group first, with a median reduction of 9 s in the time until ligation. Hyperspectral measurements showed a significant decrease in perfusion and tissue oxygenation after ligation. Further, a significant increase in perfusion and tissue oxygenation was found after reopening the tourniquet compared to the baseline measurement. CONCLUSION: The novel PAX tourniquet can be applied quickly and effectively by medical personnel without prior experience in applying a tourniquet.