Paul L. Claus

Fulminant Wilson's disease treated with postdilution hemofiltration and orthotopic liver transplantation

A 22-yr-old woman presented with fulminant Wilsons disease. The diagnosis was suspected clinically and was later confirmed with chemical and pathologic studies. She presented with acute hepatic failure, hemolysis, and acute anuric renal failure. Postdilution hemofiltration and continuous arteriovenous hemofiltration with oral D-penicillamine allowed removal of a total of 95,700 micrograms of copper; 78,665 micrograms of the total were removed via postdilution hemofiltration alone. On the 57th day, the patient received successful liver and renal transplants. We found that the determination of serum copper was instrumental in the diagnosis of fulminant Wilsons disease, that postdilution hemofiltration allowed a rapid removal of copper in the presence of renal failure, and that, finally, orthotopic liver transplantation should be performed early in the clinical course of these patients. This patient is the longest survivor of this serious condition.

Hyperbaric hyperoxia reduces exercising forearm blood flow in humans

Hypoxia during exercise augments blood flow in active muscles to maintain the delivery of O(2) at normoxic levels. However, the impact of hyperoxia on skeletal muscle blood flow during exercise is not completely understood. Therefore, we tested the hypothesis that the hyperemic response to forearm exercise during hyperbaric hyperoxia would be blunted compared with exercise during normoxia. Seven subjects (6 men/1 woman; 25 ± 1 yr) performed forearm exercise (20% of maximum) under normoxic and hyperoxic conditions. Forearm blood flow (FBF; in ml/min) was measured using Doppler ultrasound. Forearm vascular conductance (FVC; in ml·min(-1)·100 mmHg(-1)) was calculated from FBF and blood pressure (in mmHg; brachial arterial catheter). Studies were performed in a hyperbaric chamber with the subjects supine at 1 atmospheres absolute (ATA) (sea level) while breathing normoxic gas [21% O(2), 1 ATA; inspired Po(2) (Pi(O(2))) ≈ 150 mmHg] and at 2.82 ATA while breathing hyperbaric normoxic (7.4% O(2), 2.82 ATA, Pi(O(2)) ≈ 150 mmHg) and hyperoxic (100% O(2), 2.82 ATA, Pi(O(2)) ≈ 2,100 mmHg) gas. Resting FBF and FVC were less during hyperbaric hyperoxia compared with hyperbaric normoxia (P < 0.05). The change in FBF and FVC (Δ from rest) during exercise under normoxia (204 ± 29 ml/min and 229 ± 37 ml·min(-1)·100 mmHg(-1), respectively) and hyperbaric normoxia (203 ± 28 ml/min and 217 ± 35 ml·min(-1)·100 mmHg(-1), respectively) did not differ (P = 0.66-0.99). However, the ΔFBF (166 ± 21 ml/min) and ΔFVC (163 ± 23 ml·min(-1)·100 mmHg(-1)) during hyperbaric hyperoxia were substantially attenuated compared with other conditions (P < 0.01). Our data suggest that exercise hyperemia in skeletal muscle is highly dependent on oxygen availability during hyperoxia.

A systematic review and meta-analysis of adjunctive therapies in diabetic foot ulcers

BACKGROUND Multiple adjunctive therapies have been proposed to accelerate wound healing in patients with diabetes and foot ulcers. The aim of this systematic review is to summarize the best available evidence supporting the use of hyperbaric oxygen therapy (HBOT), arterial pump devices, and pharmacologic agents (pentoxifylline, cilostazol, and iloprost) in this setting. METHODS We searched MEDLINE, Embase, Cochrane Central Register of Controlled Trials, Web of Science, and Scopus through October 2011. Pairs of independent reviewers selected studies and extracted data. Predefined outcomes of interest were complete wound healing and amputation. RESULTS We identified 18 interventional studies; of which 9 were randomized, enrolling 1526 patients. The risk of bias in the included studies was moderate. In multiple randomized trials, the addition of HBOT to conventional therapy (wound care and offloading) was associated with increased healing rate (Peto odds ratio, 14.25; 95% confidence interval, 7.08-28.68) and reduced major amputation rate (odds ratio, 0.30; 95% confidence interval, 0.10-0.89), compared with conventional therapy alone. In one small trial, arterial pump devices had a favorable effect on complete healing compared with HBOT and in another small trial compared with placebo devices. Neither iloprost nor pentoxifylline had a significant effect on amputation rate compared with conventional therapy. No comparative studies were identified for cilostazol in diabetic foot ulcers. CONCLUSIONS There is low- to moderate-quality evidence supporting the use of HBOT as an adjunctive therapy to enhance diabetic foot ulcer healing and potentially prevent amputation. However, there are only sparse data regarding the efficacy of arterial pump devices and pharmacologic interventions.

Vasoconstrictor responsiveness during hyperbaric hyperoxia in contracting human muscle

Large increases in systemic oxygen content cause substantial reductions in exercising forearm blood flow (FBF) due to increased vascular resistance. We hypothesized that 1) functional sympatholysis (blunting of sympathetic α-adrenergic vasoconstriction) would be attenuated during hyperoxic exercise and 2) α-adrenergic blockade would limit vasoconstriction during hyperoxia and increase FBF to levels observed under normoxic conditions. Nine male subjects (age 28 ± 1 yr) performed forearm exercise (20% of maximum) under normoxic and hyperoxic conditions. Studies were performed in a hyperbaric chamber at 1 atmosphere absolute (ATA; sea level) while breathing 21% O(2) and at 2.82 ATA while breathing 100% O(2) (estimated change in arterial O(2) content ∼6 ml O(2)/100 ml). FBF (ml/min) was measured using Doppler ultrasound. Forearm vascular conductance (FVC) was calculated from FBF and blood pressure (arterial catheter). Vasoconstrictor responsiveness was determined using intra-arterial tyramine. FBF and FVC were substantially lower during hyperoxic exercise than normoxic exercise (∼20-25%; P < 0.01). At rest, vasoconstriction to tyramine (% decrease from pretyramine values) did not differ between normoxia and hyperoxia (P > 0.05). During exercise, vasoconstrictor responsiveness was slightly greater during hyperoxia than normoxia (-22 ± 3 vs. -17 ± 2%; P < 0.05). However, during α-adrenergic blockade, hyperoxic exercise FBF and FVC remained lower than during normoxia (P < 0.01). Therefore, our data suggest that although the vasoconstrictor responsiveness during hyperoxic exercise was slightly greater, it likely does not explain the majority of the large reductions in FBF and FVC (∼20-25%) during hyperbaric hyperoxic exercise.

Calciphylaxis: A Disease of Pannicular Thrombosis

OBJECTIVE To identify coagulation risk factors in patients with calciphylaxis and the relationship between anticoagulation use and overall survival. PATIENTS AND METHODS Study subjects were 101 patients with calciphylaxis seen at Mayo Clinic from 1999 to September 2014. Data including thrombophilia profiles were extracted from the medical records of each patient. Survival status was determined using patient registration data and the Social Security Death Index. Survival was estimated using the Kaplan-Meier method, and associations were evaluated using Cox proportional hazards models. RESULTS Sixty-four of the 101 patients underwent thrombophilia testing. Of these, a complete test panel was performed in 55 and a partial panel in 9. Severe thrombophilias observed in 60% (33 of 55) of the patients included antiphospholipid antibody syndrome protein C, protein S, or antithrombin deficiencies or combined thrombophilias. Of the 55 patients, severe thrombophilia (85%, 23 of 27) was noted in patients who were not on warfarin at the time of testing (27). Nonsevere thrombophilias included heterozygous factor V Leiden (n=2) and plasminogen deficiency (n=1). For the comparison of survival, patients were divided into 3 treatment categories: Warfarin (n=63), other anticoagulants (n=20), and no anticoagulants (n=18). There was no statistically significant survival difference between treatment groups. CONCLUSION Laboratory testing reveals a strikingly high prevalence of severe thrombophilias in patients with calciphylaxis, underscoring the importance of congenital and acquired thrombotic propensity potentially contributing to the pathogenesis of this disease. These findings may have therapeutic implications; however, to date, survival differences did not vary by therapeutic choice.

Hyperbaric Oxygen Therapy for Chronic Refractory Osteomyelitis of the Sternum

This report describes a 32-year-old woman with chronic refractory osteomyelitis of the sternum after multiple surgical procedures including a sternotomy with underlying colonic interposition that was successfully managed with hyperbaric oxygen therapy. The clinical course is reviewed, and the complexities of this diagnosis are then discussed, including a brief review of the mechanisms of management with hyperbaric oxygen therapy.

Ibuprofen in Experimental Vascular Surgery

Animal studies have been conducted to determine the effectiveness of ibuprofen in reducing early platelet deposition on small diameter (4 mm) Gore-Tex (polytetrafluoroethylene) arterial grafts and larger (10 mm) Gore-Tex grafts placed in the inferior vena cava. These studies demonstrated a significant reduction in platelet deposition at one and three hours. Additional studies of animals undergoing treatment with ibuprofen and subjected to arterial replacement with 1 or 4 mm Gore-Tex grafts demonstrated enhanced patency at 30 days. Cautious evaluation of ibuprofen as an adjunct in vascular surgery appears warranted.

Hyperbaric oxygen therapy is well tolerated and effective for ulcerative colitis patients hospitalized for moderate–severe flares: a phase 2A pilot multi-center, randomized, double-blind, sham-controlled trial

BACKGROUND: Hyperbaric oxygen therapy (HBOT) markedly increases tissue oxygen delivery. Case series suggest it may have a potential therapeutic benefit in ulcerative colitis (UC). We investigated the therapeutic potential of HBOT as an adjunct to steroids for UC flares requiring hospitalization. METHODS: The study was terminated early due to poor recruitment with 18 of the planned 70 patients enrolled. UC patients hospitalized for moderate‐severe flares (Mayo score ≥6, endoscopic sub‐score ≥2) were block randomized to steroids + daily HBOT (n = 10) or steroids + daily sham hyperbaric air (n = 8). Patients were blinded to study assignment, and assessments were performed by a blinded gastroenterologist. Primary outcome was the clinical remission rate at study day 5 (partial Mayo score ≤2 with no sub‐score >1). Key secondary outcomes were: clinical response (reduction in partial Mayo score ≥2, rectal bleeding sub‐score of 0‐1) and progression to second‐line therapy (colectomy or biologic therapy) during the hospitalization. RESULTS: A significantly higher proportion of HBOT‐treated patients achieved clinical remission at study day 5 and 10 (50 vs. 0%, p = 0.04). HBOT‐treated patients less often required progression to second‐line therapy during the hospitalization (10 vs. 63%, p = 0.04). The proportion requiring in‐hospital colectomy specifically as second‐line therapy for medically refractory UC was lower in the HBOT group compared to sham (0 vs. 38%, p = 0.07). There were no serious adverse events. CONCLUSION: In this small, proof‐of‐concept, phase 2A trial, the use of HBOT as an adjunctive therapy to steroids for UC patients hospitalized for moderate‐severe flares resulted in higher rates of clinical remission, and a reduction in rates of progression to second‐line therapy during the hospitalization. Larger well‐powered trials are needed, however, to provided definitive evidence of therapeutic benefit.

Air embolism: diagnosis and management

Air embolism is an uncommon, but potentially life-threatening event for which prompt diagnosis and management can result in significantly improved patient outcomes. Most air emboli are iatrogenic. Arterial air emboli may occur as a complication from lung biopsy, arterial catheterization or cardiopulmonary bypass. Immediate management includes placing the patient on high-flow oxygen and in the right lateral decubitus position. Venous air emboli may occur during pressurized venous infusions, or catheter manipulation. Immediate management includes placement of the patient on high-flow oxygen and in the left lateral decubitus and/or Trendelenburg position. Hyperbaric oxygen therapy is the definitive treatment which may decrease the size of air emboli by facilitating gas reabsorption, while also improving tissue oxygenation and reducing ischemic reperfusion injury.

Hyperbaric oxygen as a treatment modality in cyclophosphamide-induced hemorrhagic cystitis

Late‐onset HC is a well‐recognized complication associated with cyclophosphamide/acrolein‐induced toxicity. It poses a management challenge when hyperhydration and bladder irrigation do not result in clinical improvement as desired. The data regarding use of hyperbaric oxygen therapy (HBO2) as an early treatment modality in this clinical setting are limited. We present 2 cases, that were refractory to hyperhydration and bladder irrigation but responded to HBO2. They were treated with 20‐30 daily sessions over weekdays with 100% oxygen for 90 minutes at 2 atmospheric pressure units (2 atm). Both patients reported improved symptoms within the first 15 sessions, and hematuria diminished by 20 sessions. Hyperbaric oxygen is a less invasive, outpatient therapy that is effective for treatment of HC and is tolerated well by young patients.