Wide-awake local anesthesia and no tourniquet (WALANT) in upper limb fractures.

Wide-awake local anesthesia and no tourniquet (WALANT), first used for hand surgery, has been sparingly described for use in fracture fixation of the upper limb. We present our experience using this technique. 26 patients with upper limb fractures (3 distal radius, 6 radial shaft, 11 ulnar shaft, and 6 olecranon fractures) were operated on using WALANT by three orthopedic surgeons. We used 35-40ml of 2% Lignocaine with 1:80000 Adrenaline(7mg/kg) diluted with normal saline. Numeric Pain Rating (NPR) scoring was done during injection and per-operatively, and the Likert scale was used for the surgeon's satisfaction. The average NPR score was reported as 0.65 (1-3) during injection and 0.15 (0-2) preoperatively. All three surgeons reported excellent satisfaction in all the cases operated on. No complication occurred due to anesthesia. WALANT is a much simpler option and can be safely used in place of general anesthesia or regional blocks for fixation of fractures of the upper limb, with added advantages of no need for a tourniquet and better intraoperative assessment of fracture fixation.

Comparison of the effectiveness of the WALANT method in soft tissue and bone tissue surgeries in lower extremities.

OBJECTIVES: This study aims to investigate the effectiveness of wide-awake local anesthesia with no tourniquet (WALANT) technique in both bony and soft tissue procedures in lower extremities. PATIENTS AND METHODS: Between January 2021 and December 2022, a total of 29 patients (20 males, 9 females; mean age: 34.6±20.2 years; range, 14 to 82 years) who were operated for lower extremity pathologies with the WALANT technique in our clinic were included. The patients were divided into two groups: lower extremity soft tissue surgeries in Group A (n=10) and bone tissue surgeries in Group B (n=19). Postoperative pain onset time, pain score, the amount of intraoperative bleeding, need for additional solution, use of cautery, and the amount of bleeding in the surgical field were compared within groups. The Visual Analog Scale (VAS) was used to evaluate pain. RESULTS: There was no significant difference between the two groups in terms of age (p=0.265), sex (p=0.107), and surgical side (p=0.700). There was no significant difference between the two groups in terms of intraoperative bleeding at the discretion of the surgeon (p=0.701). There was no significant difference in the use of additional solution (p=0.105), cautery usage (p=0.522), pain onset time (p=0.636), and VAS scores (p=0.735) between the two groups. CONCLUSION: Our study results suggest that the WALANT technique is an effective and safe method in selected lower extremity surgeries. It is of utmost importance to apply the technique correctly to prevent complications that may occur.

Guidelines for Wide-Awake Local Anesthesia Surgery with No Tourniquet in the Office Setting Using Field Preparation Sterility.

SUMMARY: Wide-awake local anesthesia surgery with no tourniquet, or WALANT, has become popular in surgery, especially among hand surgeons. With the increasing number of surgeons performing office-based procedures, this article provides guidelines that may be used in the office setting to help transition more traditional hospital operating room-based procedures to the office setting. This article outlines the benefits of performing office-based wide-awake local anesthesia surgery with no tourniquet and provides a step-by-step guide to performing procedures that can be easily incorporated into any hand surgeon's practice successfully and safely.

The impact of WALANT anesthesia and office-based settings on patient satisfaction after carpal tunnel release: A patient reported outcome study.

HYPOTHESIS: Wide awake local anesthesia with no tourniquet (WALANT) and office-based procedures are used in hand surgery. There are limited literature data on patient satisfaction when comparing methods of anesthesia and location of surgery. METHODS: We conducted a retrospective single-surgeon study with patient reported satisfaction in three groups. We compared patient impressions of anesthesia type; WALANT vs locoregional anesthesia plus sedation. We also compared satisfaction in three surgery settings; office surgery vs hospital ambulatory minor procedure room vs main operating room. Group 1 office surgery patients had ultrasound guided surgery with WALANT. Group 2 main operating room surgery patients also had ultrasound guided surgery with WALANT. Group 3 main operating room patients had endoscopic surgery with sedation and a tourniquet. Each group had 30 patients with a minimum follow up of 2 months. We measured overall satisfaction, satisfaction with the organization of care, satisfaction with the administration of anesthesia, and satisfaction with the quality of anesthesia. We also collected secondary data on the resolution of the neuropathic symptoms. RESULTS: Procedures performed in an office-based setting showed higher rates of patient satisfaction when compared to the ambulatory day surgery setting. WALANT anesthesia also showed significantly higher rates of patient satisfaction on a numerical analog scale when compared to sedation based on, irrespective of the surgical setting. All patients had resolution of their neuropathic symptoms regardless of the technique performed. CONCLUSION: We found that carpal tunnel releases performed in an office-based setting produces superior patient satisfaction. WALANT anesthesia also provides improved patient satisfaction when compared to sedation and monitoring techniques, irrespective of the surgical setting and location. Carpal tunnel release with WALANT in an office-based setting is better for patient comfort and satisfaction, with no evidence of lesser clinical outcomes at a short term follow-up. LEVEL OF EVIDENCE: III.

WALANT Technique versus Sedation for Endoscopic Carpal Tunnel Release.

BACKGROUND: This study sought to investigate complication rates/perioperative metrics after endoscopic carpal tunnel release (eCTR) via wide-awake, local anesthesia, no tourniquet (WALANT) versus sedation or local anesthesia with a tourniquet. METHODS: Patients aged 18 years or older who underwent an eCTR between April 28, 2018, and December 31, 2019, by 1 of 2 fellowship-trained surgeons at our single institution were retrospectively reviewed. Patients were divided into 3 groups: monitored anesthesia care with tourniquet (MT), local anesthesia with tourniquet (LT), and WALANT. RESULTS: Inclusion criteria were met by 156 cases; 53 (34%) were performed under MT, 25 (16%) under LT, and 78 (50%) under WALANT. The MT group (46.1 ± 9.7) was statistically younger compared with LT (56.3 ± 14.1, P = .007) and WALANT groups (53.5 ± 15.8, P = .008), F(2, 153) = 6.465, P = .002. Wide-awake, local anesthesia, no tourniquet had decreased procedural times (10 minutes, SD: 2) compared with MT (11 minutes, SD: 2) and LT (11 minutes, SD: 2), F(2, 153) = 5.732, P = .004). Trends favored WALANT over MT and LT for average operating room time (20 minutes, SD: 3 vs 32 minutes, SD: 6 vs 23 minutes, SD: 3, respectively, F(2, 153) = 101.1, P < .001), postanesthesia care unit time (12 minutes, SD: 7 vs 1:12 minutes, SD: 26 vs 20 minutes, SD: 22, respectively, F(2, 153) =171.1, P < .001), and door-to-door time (1:37 minutes, SD: 21 vs 2:51 minutes, SD: 40 vs 1:46 minutes, SD: 33, respectively, F(2, 153) = 109.3, P < .001). There were no differences in complication rates. CONCLUSIONS: Our data suggest favorable trends for patients undergoing eCTR via WALANT versus MT versus LT.

Carpal tunnel release under wide awake local anesthesia with no tourniquet in hemodialysis patients with arteriovenous shunt.

INTRODUCTION: Long-term hemodialysis patients experience many hand diseases caused by dialysis-related amyloidosis (DRA), with carpal tunnel syndrome (CTS) being the most common. For the patients with arteriovenous (AV) shunt, surgical decompression remains challenging because of the contraindications of a tourniquet. A technique called wide-awake local anesthesia with no tourniquet (WALANT), in which epinephrine provides hemostasis instead of the tourniquet, can be a good option for hemodialysis patients. The purpose of this study was to assess the prevalence of CTS and related factors in hemodialysis patients, and to establish the efficacy and safety of WALANT on hemodialysis patients with AV shunt. MATERIALS AND METHODS: This prospective study included 275 hemodialysis patients between March 2013 and July 2019. 43 patients were diagnosed with CTS, involving surgical treatment on 70 wrists. We performed mini-open carpal tunnel release using WALANT on the AV shunt arm (defined as the WALANT group), while using lidocaine and a tourniquet on the arm without an AV shunt (defined as the tourniquet group). The operative time, surgical field bleeding (blood loss and hemostasis score), surgical pain (injection pain and tourniquet pain), outcomes, complications, and satisfaction were compared between the two groups. RESULTS: The incidence of CTS in hemodialysis patients was 15.6%. Longer dialysis durations were related to higher proportions of patients with CTS. There was no significant difference in blood loss (p=0.184) and hemostasis score (p=0.165) between the two groups. Clinical symptoms improved in all patients, and there were no severe complications. The WALANT group had a significantly longer preparation time of approximately 20minutes, but they had low injection pain and no tourniquet pain. There was also no significant difference in terms of satisfaction levels (p=0.212). DISCUSSION: CTS is a very common disease among hemodialysis patients. WALANT provided sufficient hemostasis without a tourniquet, despite the patients' high bleeding tendency. The technique also had the advantages of low injection pain, no tourniquet pain, and no major complications. In this respect, WALANT can be a good choice for hemodialysis patients with AV shunt. LEVEL OF EVIDENCE: II.

Comparison of the WALANT and the PFNB techniques in the surgical treatment of unimalleolar fractures: a prospective study.

The popliteal fossa nerve block (PFNB) technique is one of the most popular anesthesia method in the foot and ankle surgery. The wide awake local anesthesia no tourniquet (WALANT) technique is an local anesthetic method and it has been gaining popularity in orthopedic surgery in recent years. Our aim is to compare the efficacy of the WALANT and the PFNB techniques in pain management. This prospective study included 40 patients with lateral malleolar and medial malleolar fractures. The first group was anesthetized using the WALANT technique; in the second group, PFNB was performed. All patients were evaluated for intrasurgical bleeding amounts, mean arterial pressure, surgery time and VAS scores for presurgical pain, pain during the local anesthetic injection sequence, mean intrasurgical pain, mean postsurgical pain. A total of 40 patients in both groups were successfully operated on with the WALANT and the PFNB techniques. When the two groups were compared, statistically significant differences were observed for mean intrasurgical VAS (p = 0.033), mean postsurgical VAS (p = 0.038) and intrasurgical bleeding (p = 0.006). No significant difference was found in pain scores during anesthetic injection (p = 0.529), mean arterial pressure (p = 0.583) and surgery time (p = 0.277). The PFNB technique is more successful in pain management in the treatment of the unimalleolar fractures. Intrasurgical bleeding amounts were less detected in the WALANT tech- nique. The both techniques are a reliable and suitable anesthetic method in the surgical treatment of uni- malleolar fractures.

Is there a need for postoperative monitoring after open carpal tunnel release under WALANT?

Open carpal tunnel release (OCTR) under wide-awake local anesthesia with no tourniquet (WALANT) is a common outpatient procedure in hand surgery worldwide. In our clinic, WALANT has replaced intravenous regional anesthesia with a tourniquet (IVRA, or 'Bier block') as standard practice in OCTR. We therefore wondered what the optimal postoperative setting after OCTR under WALANT is. In this study, we compared patient satisfaction in two postoperative settings: immediate discharge (ID) after the operation, or short postoperative monitoring (PM) period in the outpatient clinic. Our hypothesis was that older patients would prefer a brief postoperative surveillance. We retrospectively analyzed patient satisfaction with the two settings using an adjusted questionnaire based on the standard Swiss grading system. We also assessed postoperative pain, satisfaction with the perioperative preparations and the reasons for unscheduled postoperative consultations, as secondary outcomes. One hundred and nine patients (ID, n = 63; PM, n = 46) were included in this single-center retrospective observational study. Patients were highly satisfied with both postoperative settings (Mean: ID 5.1/6; PM 5.5/6; p = 0.07). Even patients aged ≥80 years reported extremely high satisfaction with both settings (ID 5.6/6; PM 6.0/6; p = 0.08). Fifteen patients (ID, n = 11 [17.5%]; PM, n = 4 [8.7%], p = 0.72) unexpectedly consulted a doctor after surgery. OCTR under WALANT as an outpatient procedure with immediate discharge was associated with high patient satisfaction. However, detailed postoperative monitoring could contribute to the patient's well-being and education on how to cope with the postoperative course, and help with any questions.

Comparison of infraclavicular brachial plexus block versus wide-awake local anesthesia no-tourniquet technique in the management of radial shortening osteotomy.

OBJECTIVES: The aim of this study was to evaluate the feasibility of the wide-awake local anesthesia no-tourniquet (WALANT) technique in radial shortening osteotomy and to compare it with the infraclavicular brachial plexus block (IBPB). PATIENTS AND METHODS: Between January 2020 and January 2021, a total of 26 patients (16 males, 10 females, mean age: 40±4.9 years; range, 29 to 45 years) with Kienbock's disease who underwent radial shortening osteotomy were retrospectively analyzed. The patients were divided into two groups according to the type of anesthesia as WALANT (Group 1, n=11) and IBPB (Group 2, n=15) anesthesia. Visual Analog Scale (VAS) during surgery, time from anesthesia to surgical incision, surgical time, overall patient satisfaction regarding the anesthesia was assessed. The Quick Disabilities of the Arm, Shoulder and Hand (Q-DASH) and handgrip strengths were compared at the final follow-up and short-term outcomes were analyzed. RESULTS: Age (p=0.896), sex (p=1.000), and dominant side involvement (p=1.000) were similar between the groups. Waiting time to start surgery in both groups was similar (27 vs. 25 min; p=0.053). Intraoperative VAS-pain scores and the satisfaction from the anesthesia type of both groups were also similar (p=0.546 and p=0.500). CONCLUSION: The WALANT may be another anesthesia technique for radial shortening osteotomy with favorable outcomes. This technique adequately allows the surgeon to perform osteotomy and obtain a stable reduction without undue risk of tourniquet pain and palsy.

Ten Questions About Wide Awake Local Anaesthesia No Tourniquet (WALANT) Surgery.

The aim of this review article is to provide many important tips and tricks for surgeons to start Wide Awake Local Anaesthesia No Tourniquet (WALANT) hand surgery in their practice. The massive cost reduction of this disruptive new approach will enable them to increase access to hand surgery for their patients who cannot afford unnecessary sedation or unnecessary sterility of the expensive main operating room environment. Evidence-based sterility will permit surgeons to move a lot of their surgery out of the main operating room to minor procedure rooms without a significant increase in infection rates. Important pointers on how to inject minimally painful local anaesthesia will have patients thinking the surgeon injector is a bit of a magician. WALANT enables surgeons to improve the outcomes of many hand surgery procedures. Level of Evidence: Level V (Therapeutic).

[Application of wide-awake local anesthesia no tourniquet technique in the treatment of acute Achilles tendon rupture].

Objective: To explore the value of wide-awake local anesthesia no tourniquet (WALANT) technique in the treatment of acute Achilles tendon rupture. Methods: In a prospective randomized controlled trial, 48 patients with acute Achilles tendon rupture who met the criteria between March 2020 and October 2020 were randomly divided into two groups according to 1∶1 distribution, with 24 cases in each group. The study group used WALANT technique and the control group used epidural anesthesia with tourniquet for channel-assisted minimally invasive repair (CAMIR). There was no significant difference between the two groups in gender, age, injured side, cause of injury, distance from broken end of Achilles tendon to calcaneal tubercle, and time from injury to hospitalization ( P>0.05). The operating room use time (from patients entering the operating room to leaving the operating room), intraoperative blood loss, hospital stay, and the highest pain score [using Numerical Rating Scale (NRS)] during operation and at 1 day after operation were recorded and compared between the two groups. The tourniquet adverse reactions in the control group were recorded. The functional recovery was evaluated by the scoring method of American Orthopedic Foot and Ankle Society (AOFAS) at 12 months after operation. Results: The operation was successfully completed in both groups. The operating room use time and hospital stay in the study group were significantly less than those in the control group ( P<0.05), but the difference in the intraoperative blood loss between the two groups was not significant ( t=0.429, P=0.670). There was no significant difference in the highest NRS score during operation between the two groups ( t=1.671, P=0.101); the highest NRS score in the study group at 1 day after operation was significantly lower than that in the control group ( t=-6.384, P<0.001). In the control group, 13 patients had different degrees of tourniquet adverse reactions, including tourniquet regional pain, local swelling, blisters, thigh numbness, and discomfort. The patients in both groups were followed up 12-18 months, with an average of 13.9 months. The motor function of all patients returned to normal at 12 months after operation. The difference in AOFAS scores between the two groups was not significant ( t=0.345, P=0.731). There was no complication such as sural nerve injury, local infection, and secondary rupture in both groups. Conclusion: The application of WALANT combined with CAMIR technique in the treatment of acute Achilles tendon rupture has good anesthetic and effectiveness, avoids the adverse reactions of tourniquet, and reasonably saves social medical resources.

Wide-awake local anaesthesia no tourniquet (WALANT) procedures during COVID: a single centre experience.

Background and aim WALANT procedures are becoming more popular, and are particularly useful in the COVID-19 pandemic. Procedures can be performed without needing access to general theatres and anaesthetic support, minimising the number of patient-healthcare interactions and avoiding aerosolisation. Our unit has taken this approach and aim to present a case series that demonstrates the efficacy and safety of WALANT. Methods A prospective analysis of WALANT cases in a single plastic surgery centre during March-August 2020 was performed. All procedures using a WALANT approach were included, that would have otherwise required general anaesthetic or regional block. Data was collected on a number of variables, including patient satisfaction.  Results: 37 procedures were included in analysis. The majority of the injuries consisted of hand trauma. There were no cases of post-operative complications, although one required completion in main theatres due to technicality. No patients required additional anaesthetic during the procedure and all reported pain score as 0/10. Overall patient satisfaction was 10/10 for 26 patients, 9/10 for 10 patients and 7/10 for one patient. Conclusions Results show the use of WALANT can facilitate an effective plastic surgery trauma service during COVID-19. Most of the procedures were performed in the outpatient department setting, without the need for main operating theatres or anaesthetic support. All procedures were performed within 24 hours of initial presentation and were able to be discharged on the same day.  In addition, patient satisfaction remained high and post-operative complications were minimal. We propose that the use of WALANT should continue and increase beyond the current pandemic.

The what, why and when of wide awake local anaesthesia no tourniquet surgery.

Wide awake local anaesthesia no tourniquet, also known as WALANT, is the practice of performing surgery under local anaesthetic in the absence of a tourniquet. This technique uses the vasoconstrictive effects of adrenaline and the local anaesthetic effects of lignocaine to establish a Bier block with haemostatic control. Permitting active patient participation intraoperatively, wide awake local anaesthesia no tourniquet surgery improves patient compliance with rehabilitation and yields higher patient satisfaction. With reduced cost and equipment requirements, this method improves accessibility for patients and productivity for healthcare institutions. This is of particular benefit within the current COVID-19 climate, as wide awake local anaesthesia no tourniquet technique provides a means of overcoming restrictions to theatre access and anaesthetic support. This review delves into the current uses of wide awake local anaesthesia no tourniquet surgery, outlining the initial conception of the practice by Canadian surgeons. The advantages and disadvantages are considered, and potential future applications of this technique are discussed.

[WALANT - Wide Awake Local Anaesthesia No Tourniquet: Complications in elective and acute traumatological Hand Surgery Procedures]. / WALANT ­ Wide Awake Local Anaesthesia No Tourniquet: Komplikationen bei elektiven und akut-traumatologischen handchirurgischen Eingriffen.

INTRODUCTION: The WALANT (Wide Awake Local Anaesthesia No Tourniquet) technique has rapidly gained popularity. The advantages are often described, whereas information about complications is rare. Therefore, we followed up on our own patients regarding complications.Patients and Method Between January 2013 und June 2017, the complications experienced by one single surgeon were evaluated. The study included all elective (n = 195) and acute (n = 90) surgical procedures performed in WALANT. Minimum age of the patients was 18 years. All patients received Articaine 1 % and Suprarenine (1:200.000). Different volumes were injected with a minimum delay to surgery of 30 minutes. Complications were identified retrospectively by evaluation of patient files and a survey via telephone using a standardised questionnaire. Mean follow-up was 73 weeks. RESULTS: In 285 patients, there were 13 (4.6 %) complications. After injection of 16 ml of Articaine/Suprarenine, one patient had coronary symptoms, which ceased when two puffs of nitroglycerin spray were given. In one patient with a neurovascular injury in the palm, a bloodless field could not be obtained. A short tourniquet time was necessary for exploration. In one patient undergoing flexor tendon tenolysis, there was a need to convert to general anaesthesia with tourniquet because there was insufficient vasoconstriction due to marked scar tissue. One patient had an erythema around the injection site for a prolonged time, two had extensive erythema on the dorsum of the hand and seven patients reported swelling of the hand that lasted more than one week. SUMMARY: The WALANT method is safe. Perioperative complications are rare. Nevertheless, there are some disadvantages that should be considered.Vascular injuries, especially in fingers, are to be monitored closely regarding perfusion, and the off-label use should be remembered. Also, caution should be exercised in patients with cardiac disease. Larger injuries may need a short tourniquet time. Tissue that was operated on before does not always seem to be suitable for the technique as diffusion may be compromised. In rare cases, patients may suffer from prolonged erythema or swelling. Generally, patients should be evaluated for suitability to an operation in local anaesthesia.

Benefits of WALANT in palliative upper limb surgery after nerve injury.

Wide-Awake Local Anesthesia No Tourniquet (WALANT) may be a satisfactory anesthesia alternative for the management of upper limb peripheral nerve palsy sequelae. The main advantages are the possibility of active patient cooperation through intraoperative active mobilization, comfort and cost reduction. The legislation about WALANT in France remains unclear; the modalities of lidocaine epinephrine injection should be redefined. For palliative upper limb surgery, WALANT allows the surgeon to adjust the tension on the tendon transfer intraoperatively. Level 1 studies are needed to evaluate the effectiveness of WALANT relative to standard anesthesia techniques (regional/general anesthesia).

Virtual reality may reduce anxiety and enhance surgical experience during wide-awake local anaesthesia no tourniquet surgery: A report of two cases.

Virtual reality is an immersive experience that has been gaining acceptance in the field of medicine as a tool for reducing patient anxiety. We recently observed the effectiveness of this technology in wide-awake local anaesthesia no tourniquet (WALANT) surgeries. Here we report two cases of patients who used a virtual reality device during hand surgery using the WALANT technique. Both patients reported that the use of VR technology reduced their anxiety and improved their overall experience during surgery. This case report highlights the novel use of virtual reality during hand surgeries where the patients were awake. Based on these two cases, virtual reality may have the potential to reduce anxiety during the perioperative period and enhance a patient's overall experience in WALANT surgeries.

Patient Concerns About Wide-Awake Local Anesthesia No Tourniquet (WALANT) Hand Surgery.

PURPOSE: Wide-Awake Local Anesthetic No Tourniquet (WALANT) hand surgery avoids many medical risks associated with traditional anesthesia options. However, patients may be hesitant to choose the WALANT approach because of concerns about being awake during surgery. The purpose of this study was to characterize patients' thoughts and concerns about being awake during hand surgery and determine factors that may affect their decision about anesthesia options. METHODS: Qualitative interviews were conducted with 15 patients with a diagnosis of carpal tunnel syndrome, trigger finger, or De Quervain's tenosynovitis who were receiving nonoperative care. Interviews were conducted using a semi-structured interview guide. Inductive thematic analysis was used to identify themes, concerns, and potential intervention targets. RESULTS: Eight participants reported that patients have a general bias against being "knocked out," 7 of whom described concerns of uncertainty about emerging from anesthesia. All participants would consider WALANT, with some reservations. Recurrent themes included ensuring they would not feel, see, or hear the surgery and a preference toward distractions, such as music or engaging conversation. Of 15 participants, 13 would not want to see the surgery. For patients who found WALANT appealing, they valued the decreased time investment compared to sedation and the avoidance of side effects or exacerbation of comorbidities. A recurring theme of trust between surgeon and patient arose when deciding about anesthesia type. CONCLUSIONS: Most patients are open to WALANT, but have concerns of hearing the surgery or feeling pain. Potential interventions to address these concerns, beyond establishing a trusting physician-patient relationship, include music or video with headphones and confirming skin numbness prior to surgery. CLINICAL RELEVANCE: This study provides insights into patients' thought processes regarding WALANT hand surgery and give the surgeon talking points when counseling patients on their anesthesia type for hand surgery.

Hyperbaric oxygen therapy does not alleviate tourniquet-induced acute ischemia-reperfusion injury in mouse skeletal muscles.

During tourniquet application, blood flow is restricted to a limb to stop excessive limb hemorrhage in a trauma setting and to create a bloodless operating field in the surgical setting. During tourniquet-related ischemia, aerobic respiration stops, and ATP is depleted, and during subsequent reperfusion, there is an increase in reactive oxygen species (ROS) production and other endogenous substances, which leads to acute ischemia-reperfusion (IR) injuries, including tissue necrosis and skeletal muscle contractile dysfunction. Hyperbaric oxygen (HBO) therapy can increase the arterial oxygen tension in the tissues of patients with general hypoxia/anoxia, including carbon monoxide poisoning, circulatory arrest, and cerebral and myocardial ischemia. Here, we studied the protective effects of HBO pretreatment with 100% oxygen at 2.5 ATA against tourniquet/IR injury in mice. After one hour of HBO therapy with 100% oxygen at 2.5 ATA was administered to C57/BL6 mice, a rubber band was placed at the hip joint of the unilateral hindlimb to induce 3 h of ischemia and then released for 48 h of reperfusion. We analyzed gastrocnemius muscle morphology and contractile function and measured the levels of ATP and ROS accumulation in the muscles. HBO pretreatment did not improve tourniquet/IR-injured gastrocnemius muscle morphology and muscle contraction. Tourniquet/IR mice with HBO pretreatment showed no increase in ATP levels in IR tissues, but they did have a decreased amount of ROS accumulation in the muscles, compared to IR mice with no HBO pretreatment. These data suggest that one hour of HBO pretreatment with 100% oxygen at 2.5 ATA increases the antioxidant response to lower ROS accumulation but does not increase ATP levels in IR muscles and improve tourniquet/IR-injured muscle morphology and contractile function.