Safety of hyperbaric oxygen therapy in patients with heart failure: A retrospective cohort study.

BACKGROUND: Hyperbaric oxygen therapy (HBOT) has several hemodynamic effects including increases in afterload (due to vasoconstriction) and decreases in cardiac output. This, along with rare reports of pulmonary edema during emergency treatment, has led providers to consider HBOT relatively contraindicated in patients with reduced left ventricular ejection fraction (LVEF). However, there is limited evidence regarding the safety of elective HBOT in patients with heart failure (HF), and no existing reports of complications among patients with HF and preserved LVEF. We aimed to retrospectively review patients with preexisting diagnoses of HF who underwent elective HBOT, to analyze HBOT-related acute HF complications. METHODS: Research Ethics Board approvals were received to retrospectively review patient charts. Patients with a history of HF with either preserved ejection fraction (HFpEF), mid-range ejection fraction (HFmEF), or reduced ejection fraction (HFrEF) who underwent elective HBOT at two Hyperbaric Centers (Toronto General Hospital, Rouge Valley Hyperbaric Medical Centre) between June 2018 and December 2020 were reviewed. RESULTS: Twenty-three patients with a history of HF underwent HBOT, completing an average of 39 (range 6-62) consecutive sessions at 2.0 atmospheres absolute (ATA) (n = 11) or at 2.4 ATA (n = 12); only two patients received fewer than 10 sessions. Thirteen patients had HFpEF (mean LVEF 55 ± 7%), and seven patients had HFrEF (mean LVEF 35 ± 8%) as well as concomitantly decreased right ventricle function (n = 5), moderate/severe tricuspid regurgitation (n = 3), or pulmonary hypertension (n = 5). The remaining three patients had HFmEF (mean LVEF 44 ± 4%). All but one patient was receiving fluid balance therapy either with loop diuretics or dialysis. Twenty-one patients completed HBOT without complications. We observed symptoms consistent with HBOT-related HF exacerbation in two patients. One patient with HFrEF (LVEF 24%) developed dyspnea attributed to pulmonary edema after the fourth treatment, and later admitted to voluntarily holding his diuretics before the session. He was managed with increased oral diuretics as an outpatient, and ultimately completed a course of 33 HBOT sessions uneventfully. Another patient with HFpEF (LVEF 64%) developed dyspnea and desaturation after six sessions, requiring hospital admission. Acute coronary ischemia and pulmonary embolism were ruled out, and an elevated BNP and normal LVEF on echocardiogram confirmed a diagnosis of pulmonary edema in the context of HFpEF. Symptoms subsided after diuretic treatment and the patient was discharged home in stable condition, but elected not to resume HBOT. CONCLUSIONS: Patients with HF, including HFpEF, may develop HF symptoms during HBOT and warrant ongoing surveillance. However, these patients can receive HBOT safely after optimization of HF therapy and fluid restriction.

Adjunctive hyperbaric oxygen therapy for spinal cord ischemia after complex aortic repair.

OBJECTIVE: Spinal cord ischemia (SCI) with paraplegia or paraparesis is a devastating complication of complex aortic repair (CAR). Treatment includes cerebrospinal fluid drainage, maintenance of hemoglobin concentration (>10 g/L), and elevating mean arterial blood pressure. Animal and human case series have reported improvements in SCI outcomes with hyperbaric oxygen therapy (HBOT). We reviewed our center's experience with HBOT as a rescue treatment for spinal cord ischemia post-CAR in addition to standard treatment. METHODS: A retrospective review of the University Health Network's Hyperbaric Medicine Unit treatment database identified HBOT sessions for patients with SCI post-CAR between January 2013 and June 2021. Mean estimates of overall motor function scores were determined for postoperative, pre-HBOT, post-HBOT (within 4 hours of the final HBOT session), and at the final assessment (last available in-hospital evaluation) using a linear mixed model. A subgroup analysis compared the mean estimates of overall motor function scores between improvement and non-improvement groups at given timepoints. Improvement of motor function was defined as either a ≥2 point increase in overall muscle function score in patients with paraparesis or an upward change in motor deficit categorization (para/monoplegia, paraparesis, and no deficit). Subgroup analysis was performed by stratifying by improvement or non-improvement of motor function from pre-HBOT to final evaluation. RESULTS: Thirty patients were treated for SCI. Pre-HBOT, the motor deficit categorization was 10 paraplegia, three monoplegia, 16 paraparesis, and one unable to assess. At the final assessment, 14 patients demonstrated variable degrees of motor function improvement; eight patients demonstrated full motor function recovery. Seven of the 10 patients with paraplegia remained paraplegic despite HBOT. The estimated mean of overall muscle function score for pre-HBOT was 16.6 ± 2.9 (95% confidence interval [CI], 10.9-22.3) and for final assessment was 23.4 ± 2.9 (95% CI, 17.7-29.1). The estimated mean difference between pre-HBOT and final assessment overall muscle function score was 6.7 ± 3.1 (95% CI, 0.6-16.1). The estimated mean difference of the overall muscle function score between pre-HBOT and final assessment for the improved group was 16.6 ± 3.5 (95% CI, 7.5-25.7) vs -4.9 ± 4.2 (95% CI, -16.0 to 6.2) for the non-improved group. CONCLUSIONS: HBOT, in addition to standard treatment, may potentially improve recovery in spinal cord function following SCI post-CAR. However, the potential benefits of HBOT are not equally distributed among subgroups.

Hyperbaric oxygen therapy for treatment of COVID-19-related parosmia: a case report.

Parosmia is a qualitative olfactory dysfunction characterized by distortion of odor perception. Traditional treatments for parosmia include olfactory training and steroids. Some patients infected with COVID-19 have developed chronic parosmia as a result of their infection. Here, we present the case of a patient who developed parosmia after a COVID-19 infection that was not improved by traditional treatments but found significant improvement after hyperbaric oxygen therapy[A1].

Successful treatment of neurologic injury after complex spinal surgery with hyperbaric oxygen therapy: a case report.

Background: Neurologic injury is relatively common in the context of spinal surgery, and is often treated with physiotherapy, pharmacotherapy, or surgical intervention. Emerging evidence supports a possible role for hyperbaric oxygen therapy (HBOT) in the treatment of peripheral and spinal nerve injuries. We describe the successful use of HBOT in improving neurologic recovery after complex spine surgery with new-onset postoperative unilateral foot drop. Case Description: A 50-year-old woman was found to have new right-sided foot drop and L2-S1 motor deficits following complex thoracolumbar revision spinal surgery. She received standard conservative management for a provisional diagnosis of acute traumatic nerve ischemia, but demonstrated no neurologic improvement. On postoperative day four, after other avenues of treatment were exhausted, she was referred for HBOT. The patient received a total of twelve sessions of HBOT at 2.0 absolute atmospheres (ATA) of pressure, for 90 minutes (including two air breaks) per session, before transfer to a rehabilitation facility. Conclusions: The patient displayed marked neurologic improvement after the first hyperbaric session, and further recovery thereafter. She concluded therapy with a significantly improved range of motion and lower limb power, ability to ambulate, and pain control. HBOT was associated with a rapid, sustained improvement when applied in this case as a salvage therapy for persistent postoperative neurologic deficit. Mounting evidence supports the consideration of hyperbaric therapy as a standard adjunct treatment for traumatic neurologic injury.

Pulmonary function following hyperbaric oxygen therapy: A longitudinal observational study.

Hyperbaric oxygen therapy (HBOT) is known to be associated with pulmonary oxygen toxicity. However, the effect of modern HBOT protocols on pulmonary function is not completely understood. The present study evaluates pulmonary function test changes in patients undergoing serial HBOT. We prospectively collected data on patients undergoing HBOT from 2016-2021 at a tertiary referral center (protocol registration NCT05088772). Patients underwent pulmonary function testing with a bedside spirometer/pneumotachometer prior to HBOT and after every 20 treatments. HBOT was performed using 100% oxygen at a pressure of 2.0-2.4 atmospheres absolute (203-243 kPa) for 90 minutes, five times per week. Patients' charts were retrospectively reviewed for demographics, comorbidities, medications, HBOT specifications, treatment complications, and spirometry performance. Primary outcomes were defined as change in percent predicted forced expiratory volume in one second (FEV1), forced vital capacity (FVC), and forced mid-expiratory flow (FEF25-75), after 20, 40, and 60 HBOT sessions. Data was analyzed with descriptive statistics and mixed-model linear regression. A total of 86 patients were enrolled with baseline testing, and the analysis included data for 81 patients after 20 treatments, 52 after 40 treatments, and 12 after 60 treatments. There were no significant differences in pulmonary function tests after 20, 40, or 60 HBOT sessions. Similarly, a subgroup analysis stratifying the cohort based on pre-existing respiratory disease, smoking history, and the applied treatment pressure did not identify any significant changes in pulmonary function tests during HBOT. There were no significant longitudinal changes in FEV1, FVC, or FEF25-75 after serial HBOT sessions in patients regardless of pre-existing respiratory disease. Our results suggest that the theoretical risk of pulmonary oxygen toxicity following HBOT is unsubstantiated with modern treatment protocols, and that pulmonary function is preserved even in patients with pre-existing asthma, chronic obstructive lung disease, and interstitial lung disease.

Clinical Considerations for Implanted Neurological Devices in Patients Undergoing Hyperbaric Oxygen Therapy: A Case Report and Review of Manufacturer Guidelines.

Patients with implanted medical devices are increasingly referred for hyperbaric oxygen therapy (HBOT), and the safety of exposing some of these devices to hyperbaric environments has not previously been explored. There is a paucity of evidence surrounding the management of implanted neurological devices such as neurostimulators and intrathecal drug delivery (IDD) pumps in the context of HBOT. However, these devices can be expected to harbor unique risks; for example, vacant space in the reservoir of an implanted IDD pump may change in pressure and volume during the compression and decompression phases of HBOT, resulting in a damaged or dysfunctional device. We present the case of a 27-year-old woman with cerebral palsy referred for HBOT to manage a necrotizing soft tissue infection cultured from a dehiscent abdominal wound at the previous implantation site of an intrathecal baclofen pump. An HBOT protocol was ultimately chosen in partnership with the patient and her family, but treatment was not performed due to a paucity of evidence that the implanted IDD pump could safely withstand hyperbaric exposure. In this review, we have synthesized manufacturer recommendations regarding the management of implanted neurological devices before, during, and after HBOT to inform future decision-making in this setting. Among these recommendations, we highlight that neurostimulators should be switched off for the duration of HBOT and implanted pumps should be refilled prior to each treatment session to minimize empty reservoir space.

The role of hyperbaric oxygen therapy in the management of perioperative peripheral nerve injury: a scoping review of the literature.

BACKGROUND/IMPORTANCE: Peripheral nerve injury is an uncommon but potentially catastrophic complication of anesthesia and surgery, for which there are limited effective treatment options. Hyperbaric oxygen therapy is a unique medical intervention which improves tissue oxygen delivery and reduces ischemia via exposure to oxygen at supra-atmospheric partial pressures. While the application of hyperbaric oxygen therapy has been evidenced for other medical conditions involving relative tissue ischemia, its role in the management of peripheral nerve injury remains unclear. OBJECTIVE: This scoping review seeks to characterize rehabilitative outcomes when hyperbaric oxygen therapy is applied as an adjunct therapy in the treatment of perioperative peripheral nerve injury. EVIDENCE REVIEW: The review was conducted according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines for scoping reviews, using a systematic screening and extraction process. The search included articles published from database inception until June 11, 2022, which reported clinical outcomes (in both human and non-human models) of peripheral nerve injury treated with hyperbaric oxygen therapy. FINDINGS: A total of 51 studies were included in the narrative synthesis. These consisted of animal (40) and human studies (11) treating peripheral nerve injury due to various physiological insults. Hyperbaric oxygen therapy protocols were highly heterogenous and applied at both early and late intervals relative to the time of peripheral nerve injury. Overall, hyperbaric oxygen therapy was reported as beneficial in 88% (45/51) of included studies (82% of human studies and 90% of animal studies), improving nerve regeneration and/or time to recovery with no reported major adverse events. CONCLUSIONS: Existing data suggest that hyperbaric oxygen therapy is a promising intervention in the management of perioperative peripheral nerve injury, in which tissue ischemia is the most common underlying mechanism of injury, neurological deficits are severe, and treatment options are sparse. This positive signal should be further investigated in prospective randomized clinical trials.

The role of routine pulmonary imaging before hyperbaric oxygen treatment.

Respiratory injury during or following hyperbaric oxygen treatment (HBOT) is rare, but associated pressure changes can cause iatrogenic pulmonary barotrauma with potentially severe sequelae such as pneumothoraces. Pulmonary blebs, bullae, and other emphysematous airspace abnormalities increase the risk of respiratory complications and are prevalent in otherwise healthy adults. HBOT providers may elect to use chest X-ray routinely as a pre-treatment screening tool to identify these anomalies, particularly if a history of preceding pulmonary disease is identified, but this approach has a low sensitivity and frequently provides false negative results. Computed tomography scans offer greater sensitivity for airspace lesions, but given the high prevalence of incidental and insignificant pulmonary findings among healthy individuals, would lead to a high false positive rate because most lesions are unlikely to pose a hazard during HBOT. Post-mortem and imaging studies of airspace lesion prevalence show that a significant proportion of patients who undergo HBOT likely have pulmonary abnormalities such as blebs and bullae. Nevertheless, pulmonary barotrauma is rare, and occurs mainly in those with known underlying lung pathology. Consequently, routinely using chest X-ray or computed tomography scans as screening tools prior to HBOT for low-risk patients without a pertinent medical history or lack of clinical symptoms of cardiorespiratory disease is of low value. This review outlines published cases of patients experiencing pulmonary barotrauma while undergoing pressurised treatment/testing in a hyperbaric chamber and analyses the relationship between barotrauma and pulmonary findings on imaging prior to or following exposure. A checklist and clinical decision-making tool based on suggested low-risk and high-risk features are offered to guide the use of targeted baseline thoracic imaging prior to HBOT.

Efficacy and safety of hyperbaric oxygen treatment to treat COVID-19 pneumonia: a living systematic review update.

INTRODUCTION: As the COVID-19 pandemic evolves, new effective treatment options are essential for reducing morbidity and mortality as well as the strain placed on the healthcare system. Since publication of our initial review on hyperbaric oxygen treatment (HBOT) for hypoxaemic COVID-19 patients, interest in HBOT for COVID-19 has grown and additional studies have been published. METHODS: For this living systematic review update the previously published search strategy (excluding Google Scholar) was adopted with an extension from 01 February 2021 to 01 April 2022. Study inclusion criteria, data extraction, risk of bias estimation and dispute resolution methods were repeated. RESULTS: Two new studies enrolling 127 patients were included in this update, taking the total to eight studies with 224 patients. Both new studies were randomised controlled trials, one at moderate and one at high risk of bias. Across these eight studies, 114 patients were treated with HBOT. All reported improved clinical outcomes without observation of any serious adverse events. Meta-analysis remained unjustified given the high heterogeneity between studies and incomplete reporting. CONCLUSIONS: This updated living systematic review provides further evidence on the safety and effectiveness of HBOT to treat acute hypoxaemic COVID-19 patients.

Efficacy and safety of hyperbaric oxygen treatment in SARS-COV-2 (COVID-19) pneumonia: a systematic review.

INTRODUCTION: The need for intubation and mechanical ventilation among COVID-19 patients is associated with high mortality rates and places a substantial burden on the healthcare system. There is a strong pathophysiological rationale suggesting that hyperbaric oxygen treatment (HBOT), a low-risk and non-invasive treatment, may be beneficial for COVID-19 patients. This systematic review aimed to explore the potential effectiveness and safety of HBOT for treating patients with COVID-19. METHODS: Medline, Embase, Scopus, and Google Scholar were searched from December 2019 to February 2021, without language restrictions. The grey literature was searched via an internet search engine and targeted website and database searches. Reference lists of included studies were searched. Independent reviewers assessed studies for eligibility and extracted data, with disagreements resolved by consensus or a third reviewer. Risk of bias was assessed using the Newcastle Ottawa Scale. Data were summarised descriptively. RESULTS: Six publications (one cohort study, five case reports/series) met the inclusion criteria with a total of 37 hypoxaemic COVID-19 patients treated with HBOT. Of these 37 patients, the need for intubation and mechanical ventilation and in-hospital survival were assessed for 26 patients across three studies. Of these 26 patients, intubation and mechanical ventilation were not required for 24, and 23 patients survived. No serious adverse events of HBOT in COVID-19 patients were reported. No randomised trials have been published. CONCLUSIONS: Limited and weak evidence from non-randomised studies including one propensity-matched cohort study suggests HBOT is safe and may be a promising intervention to optimise treatment and outcomes in hypoxaemic COVID-19 patients. Randomised controlled studies are urgently needed.

Mechanistic Rationale and Clinical Efficacy of Hyperbaric Oxygen Therapy in Chronic Neuropathic Pain: An Evidence-Based Narrative Review.

Background: Chronic neuropathic pain is a condition affecting an increasing proportion of the general population and its management requires a comprehensive, multidisciplinary program. A growing body of evidence supports the use of hyperbaric oxygen therapy (HBOT) in several chronic neuropathic pain conditions; however, its role and efficacy remain unclear. Purpose: To summarize current evidence for the mechanistic rationale of HBOT in chronic neuropathic pain conditions and to evaluate its clinical efficacy. Methods: This narrative review was conducted after searching the following databases (Medline, Embase, Cochrane, PsycINFO, the Web of Science, Scopus, ClinicalTrials. gov, WHO ICTRP, and ProQuest Digital Dissertation) from January 1946 to March 2020. Articles published in English that involved either animal or human studies with acute or chronic neuropathic pain evaluating any HBOT-related intervention were included. Results: A total of 2971 citations were identified. A total of 29 studies were included in this review. The mechanisms of action for HBOT use in neuropathic conditions included the primary effects of hyperoxia and edema resolution, as well as the secondary effects pertinent to the production of oxygen and nitrogen reactive species (serving as pain signaling molecules), nitric oxide-dependent release of opioid peptides, and reduction of inflammatory mediators. A robust evidence for HBOT use in the clinical setting was associated with chronic regional pain syndrome and chronic primary bladder pain syndrome. Some evidence supported its use for chronic secondary (peripheral) neuropathic pain including radiation-induced plexus neuropathies, postherpetic neuralgia, and trigeminal neuralgia. Conclusions: HBOT has been shown to have antinociceptive and analgesic effects in animal models of inflammatory, neuropathic, and chronic pain. Human studies demonstrated beneficial effects of HBOT in improving clinical outcomes such as pain scores, pain-related symptoms, and quality of life. A systematic methodology of HBOT application is necessary to confirm its safety and efficacy.

Magnitude and Clinical Predictors of Blood Pressure Changes in Patients Undergoing Hyperbaric Oxygen Therapy: A Retrospective Study.

Hyperbaric oxygen therapy (HBOT) is widely used to treat several pathologies. The hemodynamic changes during HBOT, particularly the magnitude of arterial blood pressure (ABP) increase, are not completely understood. No clinical predictors for HBOT-induced ABP increase have been described. The purpose of this study was to quantify ABP changes in patients undergoing HBOT and to examine their predictors. This retrospective longitudinal cohort study examined 3291 elective HBOT sessions. Non-invasive ABP was recorded before and after each session. The primary outcome was to quantify the HBOT-induced ABP rise. The secondary outcome was to determine the ABP-rise predictors among demographic and clinical variables. Overall, ABP increased significantly after HBOT; this finding was more evident in the hypertensive subgroup compared to the normotensive one (+6 vs. +16.2 mmHg). Clinical predictors of significant post-HBOT ABP change were history of hypertension and pre-session baseline ABP classification. This study demonstrates an absolute HBOT-induced ABP rise. This change is clinically relevant in patients with history of hypertension. A higher baseline ABP seems a risk factor for clinically relevant ABP change. Pre-session ABP should be used clinically as an indicator for strict ABP monitoring during HBOT; future studies are recommended to explore the ABP optimization before starting an HBO treatment.

The Treatment of Perioperative Spinal Cord Injury With Hyperbaric Oxygen Therapy: A Case Report.

STUDY DESIGN: Case report (level IV evidence). OBJECTIVE: To describe a potential novel application of hyperbaric oxygen therapy (HBOT) in the successful treatment of a postoperative spinal cord injury. SUMMARY OF BACKGROUND DATA: A 68-year-old man presented with an acute spinal cord injury (ASIA impairment scale D), on the background of degenerative lower thoracic and lumbar canal stenosis. He underwent emergent decompression and instrumented fusion (T9-L5), with an uncomplicated intraoperative course and no electrophysiological changes. Immediate postoperative assessment demonstrated profound bilateral limb weakness (1/5 on the Medical Research Council [MRC] grading scale, ASIA impairment scale B), without radiological abnormality. METHODS: Conventional medical management (hypertension, level 2 care) was instigated with the addition of Riluzole, with no effect after 30 hours. At 36 hours 100% oxygen at 2.8 atmospheres was applied for 90 minutes, and repeated after 8 hours, with a further three treatments over 48 hours. RESULTS: The patient demonstrated near-immediate improvement in lower limb function to anti-gravity (MRC grading 3/5) after one treatment. Motor improvement continued over the following treatments, and after 2 weeks the patient was ambulatory. At 4 months, the patient demonstrated normal motor function with no sphincteric disturbance. CONCLUSION: The application of HBOT contributed to the immediate and sustained improvement (ASIA B to ASIA E) in motor recovery after postoperative spinal cord injury. HBOT may represent a new avenue of therapy for spinal cord injury, and requires further prospective investigation. LEVEL OF EVIDENCE: 4.

Successful Treatment of Long Standing Complex Regional Pain Syndrome with Hyperbaric Oxygen Therapy.

Complex regional pain syndrome (CRPS) is a devastating posttraumatic neuroinflammatory condition with both autoinflammatory and autoimmune features, characterized by unrelenting severe pain and disability, with the majority of affected patients being unable to function socially or vocationally. Remission is more likely in children than adults, and if treatment is started early. Once established, there are no universally effective treatments, and these are desperately needed. A single limb is often involved, but there can be multi-limb spread, and systemic autonomic manifestations. We describe a case of long-standing CRPS with multi-limb spread and systemic autonomic features, controlled only with very high dose oral corticosteroids, which led to several complications. Multiple other treatment modalities failed or were insufficient to control the CRPS and allow tapering of the corticosteroids, but the patient had a dramatic response to hyperbaric oxygen therapy (HBOT), allowing a reduction in prednisone dose to just over the physiologic range. When symptoms started to increase several months later, a second course of HBOT treatments allowed reduction in prednisone dose into the physiologic range while still controlling CRPS symptoms. This case is unique in that it shows that HBOT can be effective in long-standing CRPS, both initially, and for subsequent flares, and adds to the evidence supporting HBOT as a potential treatment for this condition. Graphical Abstract HBOT effect on prednisone dose for symptom control.

Hyperbaric oxygen therapy for spinal cord ischaemia after complex aortic repair - a retrospective review.

BACKGROUND: Complex aortic repair (CAR) carries high rates of debilitating postoperative complications, including spinal cord injury. The rate of spinal cord deficits post-CAR is approximately 10%, with permanent paraplegia in 2.9% and paraparesis in 2.4% of patients. Treatment options are limited. Rescue therapies include optimization of spinal cord perfusion and oxygen delivery by mean arterial pressure augmentation (> 90 mm Hg), cerebrospinal fluid drainage, and preservation of adequate haemoglobin concentration (> 100 g L⁻¹). Hyperbaric oxygen therapy (HBOT) has been described in several case reports as part of the multimodal treatment for spinal cord ischemia. HBOT has been used in our centre as adjunct rescue treatment for patients with spinal cord injury post-CAR that were refractory to traditional medical management, and we aimed to retrospectively review these cases. METHODS: After Research Ethics Board approval, we performed a retrospective review of all post-CAR patients who developed spinal cord injury with severe motor deficit and were treated with HBOT at our institution since 2013. RESULTS: Seven patients with spinal cord injury after CAR were treated with HBOT in addition to traditional rescue therapies. Five patients showed varying degrees of recovery, with two displaying full recovery. One developed oxygen-induced seizure, medically treated. No other HBOT-related complications were noted. CONCLUSIONS: Our retrospective study shows a potential benefit of hyperbaric oxygen therapy on neurological outcome in patients who developed spinal cord injury after CAR. Prospective research is needed to understand the role, efficacy, benefits and risks of HBOT in this setting.

Successful Treatment of Lower Limb Complex Regional Pain Syndrome following Three Weeks of Hyperbaric Oxygen Therapy.

Hyperbaric oxygen therapy (HBOT) is a treatment that delivers 100% oxygen at increased atmospheric pressures. The efficacy of HBOT for treating pain has been described in various animal pain models and may have clinical efficacy in the treatment of human chronic pain syndromes. We present our experience with posttraumatic Complex Regional Pain Syndrome (CRPS) type 2 in a patient who underwent 15 sessions of HBOT. A 41-year-old male with one-year history of CRPS of left foot followed by left ankle fracture demonstrated less pain, decreased swelling, less allodynia, and improvement in skin color and range of motion of the lower limb after 3 weeks of HBOT. Patient was back to work for the first time in over a year. HBOT may be considered as a valuable therapeutic tool in the treatment of long-standing CRPS.

Hyperbaric Oxygen Therapy: A New Treatment for Chronic Pain?

BACKGROUND AND OBJECTIVE: Hyperbaric oxygen therapy (HBOT) is a treatment providing 100% oxygen at a pressure greater than that at sea level. HBOT is becoming increasingly recognized as a potential treatment modality for a broad range of ailments, including chronic pain. In this narrative review, we discuss the current understanding of pathophysiology of nociceptive, inflammatory and neuropathic pain, and the body of animal studies addressing mechanisms by which HBOT may ameliorate these different types of pain. Finally, we review clinical studies suggesting that HBOT may be useful in treating chronic pain syndromes, including chronic headache, fibromyalgia, complex regional pain syndrome, and trigeminal neuralgia. DATABASE AND DATA TREATMENT: A comprehensive search through MEDLINE, EMBASE, Scopus, and Web of Science for studies relating to HBOT and pain was performed using the following keywords: hyperbaric oxygen therapy or hyperbaric oxygen treatment (HBOT), nociceptive pain, inflammatory pain, neuropathic pain, HBOT AND pain, HBOT AND headache, HBOT AND fibromyalgia, HBOT AND complex regional pain syndrome, and HBOT AND trigeminal neuralgia. RESULTS: Twenty-five studies examining the role of HBOT in animal models of pain and human clinical trials were found and reviewed for this narrative review. CONCLUSIONS: HBOT has been shown to reduce pain using animal models. Early clinical research indicates HBOT may also be useful in modulating human pain; however, further studies are required to determine whether HBOT is a safe and efficacious treatment modality for chronic pain conditions.

The prescription of medical cannabis by a transitional pain service to wean a patient with complex pain from opioid use following liver transplantation: a case report.

PURPOSE: The purpose of this case report is to describe a patient with a preoperative complex pain syndrome who underwent liver transplantation and was able to reduce his opioid consumption significantly following the initiation of treatment with medical cannabis. CLINICAL FEATURES: A 57-yr-old male with a history of hepatitis C cirrhosis underwent liver transplantation. Preoperatively, he was taking hydromorphone 2-8 mg⋅day(-1) for chronic abdominal pain. Postoperatively, he was given intravenous patient-controlled analgesia through which he received hydromorphone 30 mg⋅day(-1). Our multidisciplinary Transitional Pain Service was involved with managing his moderate to severe acute postsurgical pain in hospital and continued with weaning him from opioid medications after discharge. It was difficult to wean the patient from opioids, and he was subsequently given medical cannabis at six weeks postoperatively with remarkable effect. By the fifth postoperative month, his use of opioids had tapered to 6 mg⋅day(-1) of hydromorphone, and his functional status was excellent on this regimen. CONCLUSION: Reductions in opioid consumption were achieved with the administration of medical cannabis in a patient with acute postoperative pain superimposed on a chronic pain syndrome and receiving high doses of opioids. Concurrent benefits of initiating medical cannabis may include improvements in pain profile and functional status along with reductions in opioid-related side effects. This highlights the potential for medical cannabis as an adjunct medication for weaning patients from opioid use.

Type of anesthesia and postoperative delirium after vascular surgery.

OBJECTIVE: The purpose of this study was to investigate the association between general (GA), regional (RA), and local (LA) anesthetic techniques with respect to the development of delirium after vascular surgery. The authors hypothesized that patients undergoing GA for vascular surgery would have a higher incidence of postoperative delirium. The role of LA with respect to postoperative delirium in vascular surgery patients previously has not been reported. DESIGN: Retrospective review. SETTING: Tertiary referral center, university hospital. PARTICIPANTS: 500 patients undergoing vascular surgical procedures. INTERVENTIONS: Based on the chosen anesthetic technique, all patients were divided into GA, RA, and LA groups, respectively. Exclusion criteria were patients with preoperative dementia or abnormal level of consciousness, patients undergoing open abdominal aneurysm repair surgery, and patients undergoing carotid endarterectomy. All anesthetic techniques were conducted according to routine institutional practices. Patients in both the RA and LA groups received intravenous sedation. MEASUREMENTS AND MAIN RESULTS: Three hundred ninety-six (79%) patients received GA, 73 (15%) RA, and 31 (6%) LA. The overall incidence of delirium was 19.4% and rates were similar among the 3 groups, with 73 (18.4%) patients in the GA group, 17 (23.2%) in the RA group, and 7 (22.5%) in the LA group (p = 0.56). Patients in the LA group were more likely to have emergency surgery and also had a higher incidence of previous cerebrovascular accidents or transient ischemic attacks. There was no significant difference with respect to either onset or duration of delirium among the 3 groups. Median length of hospital stay and in-hospital mortality were similar among the 3 groups. CONCLUSIONS: Delirium rates after vascular surgery were similar with local, regional, or general anesthesia techniques. The presence of risk factors for the development of postoperative delirium should not influence the type of anesthesia provided.

Early benefit of preserved cognitive function is not sustained at one-year after cardiac surgery: a longitudinal follow-up of the randomized controlled trial.

PURPOSE: Recently, we showed that processing of shed blood with a continuous-flow cell saver during cardiopulmonary bypass resulted in a clinically significant reduction in postoperative cognitive decline (POCD) six weeks after coronary artery bypass graft (CABG) surgery. The current study examined if the early benefit of reduced POCD was sustained in the same patient population at one-year follow-up. METHODS: One hundred seventy patients (cell saver group, n = 84; controls, n = 86) underwent neuropsychological testing at baseline and one year after surgery. The raw scores for each test were converted to Z-scores, and a combined Z-score of ten main variables was then calculated for each study group. RESULTS: Postoperative cognitive decline was present in 16 of 84 (19%) patients in the cell saver group (95% confidence interval [CI], 10.8 to 27.2) vs 15 of 86 (17.4%) patients in the control group (95% CI, 9.6 to 25.2) (P = 0.786). Six of the 15 patients in the control group with POCD at six weeks had the impairment at one year and five did not; four were lost to follow-up. Three of the six cell saver patients with POCD at six weeks still had impairment at one year, two did not, and one was not tested. Thirteen (15.4%) and nine (10.5%) patients in the cell saver and control groups, respectively, developed new POCD which was not evident at the six-week follow-up. CONCLUSIONS: The short-term preservation of cognitive function in elderly patients using the cell saver management strategy did not translate into a long-term benefit one year after CABG surgery. The presence of progressing cerebrovascular disease may be responsible for the long-term cognitive decline.