Delayed recognition of Type II decompression sickness in a diver with chronic atrial fibrillation.

Introduction: This case report describes an initially overlooked Type II decompression sickness (DCS) occurrence that was confused with a cerebral vascular accident in a patient with chronic atrial fibrillation (AF). The purpose of this case report is to reinforce the maxim that DCS needs to be suspected anytime a scuba diver experiences signs or symptoms compatible with DCS after completing a scuba dive. Methods: A 71-year-old scuba diver with a history of AF and who was taking warfarin made four dives, all with maximum depths less than 60 fsw (20 msw) over a 10-hour interval. Shoulder pain developed before entering the water on the fourth dive and was worse after exiting from the fourth dive. Twenty minutes later the diver collapsed while standing and was unable to make a grip using his left hand. A literature review failed to locate any case reports of divers with AF presenting with strokelike symptoms only to find the cause was Type II DCS.. Findings: Initially the patient's findings were reviewed with a diving medicine team. The recommendation was for the patient to be managed for a stroke. The patient was transferred to a hospital for a computed tomography scan, but no recommendation was made for a hyperbaric oxygen recompression treatment. The scan showed no brain bleed or infarct. The attending neurologist (not diving medicine-trained) was concerned that the patient's findings were diving-related and arranged for transferring the patient to a hyperbaric medicine facility 25 hours later. With hyperbaric oxygen (HBO2) therapy the patient's symptoms remitted over several weeks. Conclusion: The presence of symptoms attributed to a stroke immediately after a scuba dive should not deter a trial of HBO2 therapy. The delay in starting HBO2 therapy is concerning and perhaps the reason recovery was delayed and the need for repetitive HBO2 therapies.

The role of hyperbaric oxygen for acute traumatic ischemias.

Acute traumatic ischemias are an array of disorders that range from crush injuries to compartment syndromes, from burns to frostbite and from threatened flaps to compromised reimplantations. Two unifying components common to these conditions are a history of trauma be it physical, thermal, or surgical coupled with ischemia to the traumatized tissues. Their pathophysiology resolves around the self-perpetuating cycle of edema and ischemia, and their severity represents a spectrum from mild, almost non-existent, to tissue death. Since ischemia is a fundamental component of the traumatic ischemias and hypoxia is a consequence of ischemia, hyperbaric oxygen is a logical intervention for those conditions where tissue survival, infection control and healing is at risk. Unfortunately, even with mechanisms of hyperbaric oxygen that strongly support its usefulness in traumatic ischemias coupled with supportive clinical data, clinicians are disinclined to utilize it for these conditions. This focuses on the orthopedic aspects of the traumatic ischemias, namely crush injury and compartment syndrome, and show how hyperbaric oxygen treatments can mitigate their severity.

The Gradient Perfusion Model Part 3: An extraordinary case of decompression sickness.

INTRODUCTION: Decompression sickness (DCS) has been associated with unusual circumstances such as breath-hold diving, shallow depths, and short bottom times. We report a case of DCS with an extraordinary cause and course. MATERIALS AND METHODS: A 72-year-old healthy Hispanic female was referred to our 24/7 Hyperbaric Medicine Unit for emergency hyperbaric oxygen recompression treatment (HBO2 RCT) after developing lower-extremity paralysis following a hyperbaric air exposure in a homemade hyperbaric chamber. RESULTS: After an uneventful exposure to hyperbaric air at a maximum 72-foot depth (3.2 ATA, 32.3 psig), the patient had the delayed onset of abdominal pain and paraplegia after eating a meal. After HBO2 RCT in accordance with our management algorithm, the patient had a full recovery. CONCLUSIONS: This patient's presentation and course corresponded to what we label as "disordered decompression" and conformed to our Gradient Perfusion Model. With a finite blood volume and the need to perfuse two "intermediate" tissues simultaneously, we postulate that a "steal" syndrome arose to cause the abdominal and paralysis symptoms.

The Incidence of Confounding Factors in Patients With Diabetes Mellitus Hospitalized for Diabetic Foot Ulcers.

INTRODUCTION: Uncontrolled deformity, deep infection, and/or ischemia-hypoxia are highly associated with healing challenges of diabetic foot ulcers (DFUs). This paper reports the occurrences of these factors that the authors label the "Troublesome Triad" (TT) in a prospective series of 62 patients with diabetes mellitus (DM), who were hospitalized because of their DFUs. MATERIALS AND METHODS: With Institutional Review Board approval, the authors gathered data in a prospective series of patients hospitalized because of lower extremity wounds. From this data, they analyzed the DFU cohort for the incidence of each of the components of the TT. The severity of the wound was graded with the authors' 0 to 10 Wound Score in the patients who had components of the TT and compared with those who did not. RESULTS: One or more components of the TT were observed in 57 patients (91.9%). As the number of confounders increased, mean Wound Scores decreased from 5.2 for 1 confounder to 2.9 for 3 confounders (P = 0.003). Most patients had 1 or 2 confounders (38.7% and 45.2%, respectively), while only 5 (8.1%) patients had all 3 confounders. Unresolved infection was the major confounder in 38 (61.3%) patients, uncontrolled deformity in 31 (50.0%), and ischemia-hypoxia in 26 (41.9%). CONCLUSION: For those patients with DM who were hospitalized because of DFUs, confounders that require remedial interventions were present in more than 90% of patients. Recognition and management of the TT eliminates wasteful uses of resources in an attempt to heal lower extremity wounds in patients with DM where the confounders need to be addressed first.

The validity of transcutaneous oxygen measurements in predicting healing of diabetic foot ulcers.

INTRODUCTION: In 2002 Fife and Strauss (Fife, et al. Wound Rep Reg, 10:198-207; Strauss, et al. Foot Ankle Intl, 23:933-937) studied the predictability of transcutaneous oxygen measurements (TCOMs) for healing diabetic foot ulcers (DFUs). This paper analyzes the validity of the two studies and combines their information to predict which DFU will heal with adjunctive hyperbaric oxygen (HBO2) treatments. METHODS: A statistical review of the Fife and Strauss papers was performed. The numbers presented in the papers were subjected to analyses to compare like by like data as well as test for p-values and odds ratios for predicting healing of DFUs with HBO2. RESULTS: In the Strauss paper 143 subjects were studied in retrospective and prospective series. In those TCOMs which exceed 200 mmHg with HBO2 healing occurred in 87.5% even if the room air TCOM was ⟨ 30 mmHg (p ⟨ 0.001). The Fife paper studied retrospectively a subset of 221 patients who had TCOMs with HBO2. Failure rates for healing decreased progressively from 35.7% to 14.3%, with TCOMs grouped in 100-mmHg increments from 200 mmHg to 699 mmHg. This resulted in absence of statistical significance for any 100-mmHg range over 200 mmHg with HBO2 due to the small number of subjects for each 100-mmHg grouping. CONCLUSIONS: Although differences exist between the study designs, each complements the other. If TCOMs exceed 200 mmHg with HBO2, both authors observed that almost 90% of DFUs healed regardless of the room air readings when HBO2 was used as an adjunct to management.

A clinical practice guideline for the use of hyperbaric oxygen therapy in the treatment of diabetic foot ulcers.

BACKGROUND: The role of hyperbaric oxygen (HBO2) for the treatment of diabetic foot ulcers (DFUs) has been examined in the medical literature for decades. There are more systematic reviews of the HBO2/DFU literature than there have been randomized controlled trials (RCTs), but none of these reviews has resulted in a clinical practice guideline (CPG) that clinicians, patients and policy-makers can use to guide decision-making in everyday practice. METHODS: The Undersea and Hyperbaric Medical Society (UHMS), following the methodology of the Grading of Recommendations Assessment, Development and Evaluation (GRADE) Working Group, undertook this systematic review of the HBO2 literature in order to rate the quality of evidence and generate practice recommendations for the treatment of DFUs. We selected four clinical questions for review regarding the role of HBO2 in the treatment of DFUs and analyzed the literature using patient populations based on Wagner wound classification and age of the wound (i.e., acute post-operative wound vs. non-healing wound of 30 or more days). Major amputation and incomplete healing were selected as critical outcomes of interest. RESULTS: This analysis showed that HBO2 is beneficial in preventing amputation and promoting complete healing in patients with Wagner Grade 3 or greater DFUs who have just undergone surgical debridement of the foot as well as in patients with Wagner Grade 3 or greater DFUs that have shown no significant improvement after 30 or more days of treatment. In patients with Wagner Grade 2 or lower DFUs, there was inadequate evidence to justify the use of HBO2 as an adjunctive treatment. CONCLUSIONS: Clinicians, patients, and policy-makers should engage in shared decision-making and consider HBO2 as an adjunctive treatment of DFUs that fit the criteria outlined in this guideline. The current body of evidence provides a moderate level of evidence supporting the use of HBO2 for DFUs. Future research should be directed at improving methods for patient selection, testing various treatment protocols and improving our confidence in the existing estimates.

The effect of hyperbaric oxygen in crush injuries and skeletal muscle-compartment syndromes.

Crush injuries represent a spectrum of injury to body parts as result of trauma. Presentations vary from minor contusions to limb-threatening damage. Typically, the injury involves multiple tissues, from skin and subcutaneous, to muscle and tendons, to bone and joints. In their most severe presentations, predictable complications--including osteomyelitis, non-union of fractures, amputations and failed flaps--occur in approximately 50 percent of the cases with standard of practice surgical and medical interventions. Skeletal muscle-compartment syndrome (SMCS) is another consequence of trauma, but in this situation the target tissues are muscles and nerve. Edema and/or bleeding within the confines of the fascial envelope can increase the pressure within the skeletal muscle-compartment. When the tissue fluid pressure within the compartment exceeds the capillary perfusion pressure to the muscles and nerves in the compartment, these tissues are rendered ischemic and manifest the signs and symptoms of SMCS. The SMCS, especially in its incipient stages before a fasciotomy is required, is a therapeutic challenge since no means to arrest its progression exist other than hyperbaric oxygen (HBO2). Unfortunately, HBO2 is woefully neglected as an adjunct for managing crush injury and SMCS. Strong arguments exist for its use based on evidenced-based information and how HBO2 mitigates the pathology of these conditions.

Effects of cigarette smoking on tissue gas exchange during hyperbaric exposures.

OBJECTIVES: In this study we investigate whether differences exist in human skeletal muscle (MM) and subcutaneous (SC) tissue gas tensions between chronic cigarette smokers and non-smokers measured under room air and hyperbaric conditions. METHODS: Gas tensions in resting MM and SC tissues were recorded using a mass spectrometer at four-minute intervals during two and one-half to three-hour period in smokers and non-smokers during normobaric, normoxic (room air) and hyperbaric conditions. Two hyperbaric oxygen (HBO2) protocols were utilized: Protocol A employed the continuous breathing of oxygen (O2) at 2 ATA, a typical monoplace hyperbaric chamber treatment, while Protocol B utilized intermittent air breaks between O2 breathing periods at 2 ATA representative of a multiplace hyperbaric chamber treatment. RESULTS: All tissue gas tensions changed significantly (repeated measures of variance, p=0.00001) with time as pressures and gas mixtures breathed were altered. Significant Individual Step Analysis (ISA) differences occurred with unloading of nitrogen (N2) from the muscle compartment in both protocols (T-test and Wilcoxon Rank Sum). The interaction of grouping variable and time revealed significant differences between smokers and non-smokers in unloading MM N2 in both protocols: Protocol A (p=0.02) and in Protocol B (p=0.022). Carbon dioxide (CO2) levels in both protocols decreased significantly with time when exposed to HBO2 while increasing when breathing air at 2 ATA. CONCLUSIONS: This study demonstrates: 1) Smokers release MM N2 more slowly than nonsmokers during hyperbaric oxygen exposures regardless of the treatment protocol used; 2) There were no significant differences in O2 loading of MM and SC tissues during HBO2 exposures between smokers and nonsmokers; 3) The CO2 levels in both protocols decrease with time when exposed to HBO2 while increasing with breathing air at 2 ATA; 4) The known vasoconstriction effect in subcutaneous tissue from nicotine lasts less than one hour with the topical adiabatic heating increasing the O2 loading specifically in the SC tissues of smokers; 5) Wounds heal more slowly due to the chronically injured endothelium from carbon monoxide, hydrogen cyanide, and other toxic products in smoke rather than from the transient elevations of nicotine.

Does hyperbaric oxygen exposure affect high-intensity, short-duration exercise performance?

Hyperbaric oxygen (HBO) exposure involves the breathing of 100% oxygen under conditions of elevated atmospheric pressure and is used to increase the oxygen content of the plasma fraction of arterial blood. The purpose of this study was to determine the effects of acute HBO exposure on selected physiological responses and performance in response to maximal lower extremity or upper extremity short-term, high-intensity exercise. The study was performed with 2 separate experiments incorporating double-blinded and randomized protocols. In experiment 1, 9 subjects ran on a treadmill at a speed of 268 m x min(-1) with a predetermined grade. In experiment 2, 9 different subjects performed a repetitive bench press exercise. Both exercise protocols were designed to induce fatigue within 1-2 minutes. Within each experiment, subjects received either a 1-hour HBO exposure inspiring 100% O2 at 202.6 kPa (2.0 atmospheres absolute pressure [ATA]) or a 1-hour sham exposure inspiring ambient air at 121.5 kPa (1.2 ATA) before exercise. No significant differences (p > or = 0.05) were observed in postexercise blood lactate concentrations, peak heart rate, ratings of perceived exertion, or performance as determined by treadmill running time or number of completed lifts. Unlike other methods that elevate oxygen content of the blood, acute HBO exposure appears to have no significant effect on subsequent high-intensity running or lifting performance.

Hyperbaric oxygen as an intervention for managing wound hypoxia: its role and usefulness in diabetic foot wounds.

Few topics in diabetic wound management generate as much "heated" discussion as hyperbaric oxygen (HBO). Hyperbaric oxygen is an intermittent inhalation therapy in which the patient breathes oxygen at greater than 1 atm of pressure. This requires placement of the patient into a sealed vessel (chamber) which is capable of withstanding pressurization. This article discusses the role of HBO as an adjunct to the management of diabetic problem foot wounds from evidenced-based, approved (by Medicare) indications and cost-effectiveness perspectives.

Transcutaneous oxygen measurements under hyperbaric oxygen conditions as a predictor for healing of problem wounds.

Controversy exists as to what transcutaneous oxygen (P(tc)O2) levels are required for wound healing and what role hyperbaric oxygen has for this. Current information suggests that 30 to 40 mmHg juxta-wound oxygen tensions in room air are required. We recorded P(tc)O2 measurements in room air and with hyperbaric oxygen in 190 patients with foot wounds; then looked retrospectively and prospectively whether there was any effect on healing. Transcutaneous oxygen measurements under hyperbaric oxygen conditions defined a responder group (P(tc)O2 > 200 mmHg) with a sensitivity of 0.80 and a positive predictive value of 0.88 for healing, regardless of room air measurements when hyperbaric oxygen was used as an adjunct to wound management. This information helps to objectify the indications for hyperbaric oxygen and predict healing especially in those patients with problem wounds of the foot and ankle.

Forefoot narrowing with external fixation for problem cleft wounds.

Healing of forefoot cleft wounds can be a difficult management problem in patients with peripheral vascular disease, diabetes or both. This is a prospective review of 15 patients with these conditions with nonhealing middle-ray cleft wounds managed with a temporary mini-external fixator to close the cleft wound. Fourteen (93%) of the 15 patients had a successful obliteration of the cleft and skin coverage. Twelve (80%) of 15 were able to resume their previous level of activity with the reconstructed, mechanically sound forefoot. Fourteen (93%) of the 15 patients received hyperbaric oxygen treatments as an adjunct to wound healing. All patients avoided a transmetatarsal or higher amputation.

Hyperbaric oxygen.

This cutting edge article discusses the most frequent uses of hyperbaric oxygen for the orthopedic surgeon. Hyperbaric oxygen therapy is an adjunct to orthopedic interventions when healing problems are anticipated due to wound hypoxia or uncontrolled infection.