A case of a critically injured diver with multiorgan failure and severe pulmonary overinflation syndrome in a resource-limited setting.

A diver practicing controlled emergency ascent training on the island of Guam suffered bilateral pneumothorax, pneumomediastinum, coronary arterial gas embolism, and developed multiple organ dysfunction syndrome. Due to limitations of available resources he was medically managed in the intensive care unit until he could be transferred to University of California San Diego for definitive management. We provide an account of our management of the patient, the pathophysiology of injury as well as a review of the safety of recreational diving skills training, current standards of practice and potential pitfalls when considering proper management of a critically injured diver.

Optimal treatment strategies for hepatic portal venous gas: A retrospective assessment.

BACKGROUND: Hepatic portal venous gas (HPVG) generally indicates poor prognoses in patients with serious intestinal damage. Although surgical removal of the damaged portion is effective, some patients can recover with conservative treatments. AIM: To establish an optimal treatment strategy for HPVG, we attempted to generate computed tomography (CT)-based criteria for determining surgical indication, and explored reliable prognostic factors in non-surgical cases. METHODS: Thirty-four cases of HPVG (patients aged 34-99 years) were included. Necessity for surgery had been determined mainly by CT findings (i.e. free-air, embolism, lack of contrast enhancement of the intestinal wall, and intestinal pneumatosis). The clinical data, including treatment outcomes, were analyzed separately for the surgical cases and non-surgical cases. RESULTS: Laparotomy was performed in eight cases (surgical cases). Seven patients (87.5%) survived but one (12.5%) died. In each case, severe intestinal damage was confirmed during surgery, and the necrotic portion, if present, was removed. Non-occlusive mesenteric ischemia was the most common cause (n = 4). Twenty-six cases were treated conservatively (non-surgical cases). Surgical treatments had been required for twelve but were abandoned because of the patients' poor general conditions. Surprisingly, however, three (25%) of the twelve inoperable patients survived. The remaining 14 of the 26 cases were diagnosed originally as being sufficiently cured by conservative treatments, and only one patient (7%) died. Comparative analyses of the fatal (n = 10) and recovery (n = 16) cases revealed that ascites, peritoneal irritation signs, and shock were significantly more frequent in the fatal cases. The mortality was 90% if two or all of these three clinical findings were detected. CONCLUSION: HPVG related to intestinal necrosis requires surgery, and our CT-based criteria are probably useful to determine the surgical indication. In non-surgical cases, ascites, peritoneal irritation signs and shock were closely associated with poor prognoses, and are applicable as predictors of patients' prognoses.

Exploring the use of single-port surgery in the conservative management of hepatic portal vein gas: A case report.

RATIONALE: Hepatic portal vein gas (HPVG) is known as a sign of a lethal condition resulting from bowel necrosis. Recently, the detection rate of non-life-threatening cases of HPVG has increased due to the technological development of imaging, i.e., computed tomography (CT). However, it is difficult to determine accurately whether surgical treatment is necessary because of its lethal potential. PATIENT CONCERNS: A 74-year-old woman suddenly complained about lower abdominal pain and vomiting after an operation for cervical spondylosis myelopathy. Her vital signs were slightly unstable and she was perspiring and exhibited pallor. Muscular defense was not clear, though her abdomen was tender and slightly distended. DIAGNOSIS: CT results showed massive HPVG. However, laboratory investigation did not clearly indicate bowel necrosis. Also, a contrast-CT scan was not performed due to her chronic renal dysfunction and asthma. INTERVENTION: Exploration was performed by single-port surgery (SPS) instead of exploratory laparotomy. OUTCOME: This approach showed no ischemic bowel and so conservative therapies were undertaken with confidence. The HPVG disappeared 2 days later, and she recover completely from the illness. LESSONS: HPVG requires immediate and reliable decision for management. However, unnecessary exploratory laparotomy should be avoided. Hence, a novel strategy should be considered in light of innovative surgical procedures. Our experience suggested that SPS was useful as an exploratory tool for the management of HPVG.

[Diving accidents]. / Tauchunfälle.

Decompression injuries occur on account of the special hyperbaric effects during the emerge phase and require superior therapeutic knowledge. Vitally important is emergency treatment with high concentrated oxygen at an early stage. Sever decompression injuries require oxygenation in a hyperbaric treatment chamber.

Hyperbaric programs in the United States: Locations and capabilities of treating decompression sickness, arterial gas embolisms, and acute carbon monoxide poisoning: survey results.

Hyperbaric oxygen therapy is the primary treatment for arterial gas embolism, decompression sickness and acute carbon monoxide poisoning. Though there has been a proliferation of hyperbaric centers throughout the United States, a scarcity of centers equipped to treat emergency indications makes transport of patients necessary. To locate and characterize hyperbaric chambers capable of treating emergency cases, a survey of centers throughout the entire United States was conducted. Using Google, Yahoo, HyperbaricLink and the UHMS directory, a database for United States chambers was created. Four researchers called clinicians from the database to administer the survey. All centers were contacted for response until four calls went unreturned or a center declined to be included. The survey assessed chamber readiness to respond to high-acuity patients, including staff availability, use of medical equipment such as ventilators and intravenous infusion devices, and responding yes to treating hyperbaric emergencies within a 12-month period. Only 43 (11.9%, N = 361) centers had equipment, intravenous infusion pumps and ventilators, and staff necessary to treat high-acuity patients. Considering that a primary purpose of hyperbaric oxygen therapy is the treatment of arterial gas embolism and decompression sickness, more hyperbaric centers nationwide should be able to accommodate these emergency cases quickly and safely.

Preventing central line air embolism.

The Pennsylvania Patient Safety Reporting System is a confidential, statewide Internet reporting system to which all Pennsylvania hospitals, outpatient-surgery facilities, birthing centers, and abortion facilities must file information on incidents and serious events.Safety Monitor is a column from Pennsylvania's Patient Safety Authority, the authority that informs nurses on issues that can affect patient safety and presents strategies they can easily integrate into practice. For more information on the authority, visit www.patientsafetyauthority.org. For the original article discussed in this column or for other articles on patient safety, click on "Patient Safety Advisories" and then "Advisory Library" in the left-hand navigation menu.

Intraoperative cardiac assessment with transesophageal echocardiography for decision-making in cardiac anesthesia.

Transesophageal echocardiography is an invaluable hemodynamic monitoring modality. Extended and anatomically based evaluation of cardiac function with transesophageal echocardiography is essential to prompt and accurate decision-making in anesthetic management during cardiac surgery. Fractional shortening and fractional area changes are indices widely used to assess the global systolic performance of the left ventricle. Monitoring regional function using semi-quantitative scoring has been demonstrated to be a more sensitive indicator of myocardial ischemia. Assessment of left ventricular diastolic function should be performed in a systematic way, measuring transmitral flow, pulmonary venous flow, transmitral color M-mode flow propagation velocity, and mitral annulus tissue Doppler imaging. The unique anatomical features of the right ventricle make echocardiographic evaluation complicated and therefore less frequently employed. Right ventricular fractional area change, tricuspid annular plane systolic excursion, maximal systolic tricuspid annular velocity with tissue Doppler imaging, and myocardial performance index are indices successfully incorporated into intraoperative right ventricular assessment. Left ventricular outflow tract obstruction with systolic anterior motion of the mitral valve may develop after cardiac procedures. Transesophageal echocardiography plays a central role in prevention as well as diagnosis of systolic anterior motion. Transesophageal echocardiography is extremely useful not only for detecting and locating intracardiac air, but also for guiding and evaluating the procedures to remove air. Air is likely to persist in the right and left superior pulmonary vein, left ventricular apex, left atrium, right coronary sinus of Valsalva, and ascending aorta. Accurate evaluation of cardiac function depends on performing TEE examination properly and obtaining optimal images.

Informe de evaluación rápida de tecnología sobre seguridad y efectividad de la oxigenoterapia hiperbárica / Rapid evaluation report of technology on safety and effectiveness of hyperbaric oxygen therapy

La oxigenación hiperbárica es una modalidad terapéutica no invasiva en la cual el pacientes respira oxígeno puro en el interior de una cámara de acero herméticamente cerrada, a presión atmosférica mayor a la ambiental (cámara hiperbárica). Existen solo dos efectos básicos que describen el mecanismo de acción de la OHB en el cuerpo humano, los cuales son: a. El efecto volumétrico, producido por la presión aumentada a la cual se somete el organismo. Dicho efecto es de fundamental importancia en la reducción del tamaño de las burbujas de gas que pueden contener los tejidos corporales como consecuencia de un accidente de buceo o iatrogenia médica (embolismo gaseoso en las intervenciones quirúrgicas u otros procedimientos terapéuticos invasivos), o el producido por bacterias anaerobias. b. El segundo efecto es solumétrico, debido al incremento de la presión parcial de oxígeno en los tejidos, siendo este multifacético, ya que a las presiones atmosféricas manejadas en este tratamiento el oxígeno se comporta como un fármaco con indicaciones específicas y posibles efectos adversos. Se recomienda cubrir en las siguientes condiciones: enfermedad por descompresión, embolia gaseosa, gangrena gaseosa, intoxicación por monóxido de carbono, fasceitis necrotizante, gangrena de Fournier, lesiones de pie diabético grado IV de Wagner, lesiones de bóveda craneal, parrilla costal, esternón, mandíbula, proctitis y enteritis.(AU)

Incidence and management of venous air embolisms during awake deep brain stimulation surgery in a large clinical series.

BACKGROUND/AIMS: Venous air embolism (VAE) is a potential complication during neurosurgical procedures, particularly in the sitting position. The diagnosis and management of VAE in patients undergoing awake deep brain stimulation (DBS) lead implantation in the sitting position are underreported. METHODS: We performed a retrospective chart review of 467 consecutive DBS surgeries at the University of California, San Francisco. Data was collected for patient demographics, diagnosis, intraoperative events, and postoperative course. RESULTS: Six cases of clinically diagnosed VAE were found, amounting to a total incidence of 1.3% per procedure. We did not observe a statistical association with patient age, diagnosis, or DBS target. The most common symptoms of intraoperative VAE were coughing, oxygen desaturation, and hypotension. In all cases, VAE was treated by copious irrigation of the surgical field and lowering the patient's head. In 4 cases, DBS implantation was abandoned because of ongoing symptoms of VAE. The respiratory outcome in all patients was good after several days of close observation. CONCLUSION: The incidence of VAE during DBS procedures is small, but prompt recognition and management of VAE are critical to avoid further associated complications.

Indications de l'oxygénothérapie hyperbare: mise à jour / Indications for hyperbaric oxygen therapy: update

INTRODUCTION: Dans la première moitié du XXe siècle, l'oxygénothérapie hyperbare (OHB) fut utilisée pour le traitement des accidents de décompression. D'autres indications se sont ajoutées au fil des ans, de sorte que l'OHB est aujourd'hui recommandée par l'Hyperbaric Oxygen Therapy Committee de l'Undersea and Hyperbaric Medical Society (UHMS) pour prévenir ou traiter les 13 affections suivantes: 1) les accidents de décompression; 2) l'embolie gazeuse; 3) l'intoxication au monoxyde de carbone; 4) les radionécroses; 5) les plaies réfractaires; 6) les brûlures thermiques; 7) les problèmes de greffes de peau et de tissus; 8) la gangrène gazeuse; 9) les infections nécrosantes des tissus mous; 10) l'ostéomyélite réfractaire; 11) l'abcès intracrânien; 12) les lésions par écrasement, les syndromes compartimentaux et les traumatismes ischémiques aigus; et 13) les anémies particulières. Toutefois, à l'exception des situations d'urgence comme les accidents de décompression et les embolies gazeuses, les applications de l'OHB demeurent controversées dans la littérature scientifique. Dans ce contexte, le ministre de la Santé et des Services sociaux a demandé à l'Agence d'évaluation des technologies et des modes d'intervention en santé (AETMIS) de revoir l'état actuel des connaissances sur l'utilisation de l'OHB pour la prévention et le traitement de ces 13 affections. Plus précisément, il désire savoir si depuis la publication du rapport du Conseil d'évaluation des technologies de la santé (CETS, le prédécesseur de l'AETMIS) en 2000, de nouvelles recherches ont donné des résultats probants quant à l'efficacité de cette technologie et si d'autres indications peuvent s'ajouter aux 13 premières. Rappelons que l'AETMIS a produit récemment deux rapports sur la place de l'OHB dans la prise en charge de la paralysie cérébrale et de l'autisme, deux indications non reconnues par les sociétés savantes. RÉSULTATS: Les études quantitatives et qualitatives publiées depuis 2000 sur les 13 indications et quelques autres affections traitées avec l'OHB ont été analysées. En ce qui concerne le traitement de la surdité cochléaire soudaine idiopathique, les connaissances actuelles indiquent que l'OHB réduirait significativement la perte d'audition dans les premières semaines suivant son apparition. Cependant, l'importance clinique de ce gain reste incertaine et ne peut donc justifier, pour le moment, le recours systématique à l'OHB sans l'appui de nouvelles études. Par contre, les experts de l'ECHM maintiennent la recommandation de 1994, qui préconise l'OHB pour le traitement de cette affection, jusqu'à ce qu'une étude européenne en cours sur le sujet soit terminée. Enfin, la place de l'OHB dans la prise en charge de la paralysie cérébrale et de l'autisme a été examinée de façon exhaustive dans deux rapports récents (2007) de l'AETMIS : selon l'état actuel des connaissances, ces applications restent expérimentales et la démonstration de leur efficacité nécessite des essais cliniques comparatifs rigoureux. CONCLUSION: L'objectif principal de ce rapport était de mettre à jour le précédent rapport du CETS publié en 2000 sur les indications reconnues de l'oxygénothérapie hyperbare (OHB). Étant donné la rareté de nouvelles études et la faible qualité de plusieurs d'entre elles, l'AETMIS a appuyé en grande partie son évaluation sur des consensus d'experts, dont les deux principaux sont issus de l'Hyperbaric Oxygen Therapy Committee de l'Undersea and Hyperbaric Medical Society (UHMS) et de l'European Committee for Hyperbaric Medicine (ECHM). Au terme de son évaluation, l'AETMIS conclut que les indications recommandées de l'oxygénothérapie hyperbare demeurent semblables, dans leur ensemble, bien que des précisions se soient ajoutées. Selon les données probantes (regroupées selon trois niveaux de preuve : A - élevé, B - moyen et C - faible), la liste des indications se présente maintenant comme suit: I. Indication recommandée en prévention: Ostéoradionécrose après une extraction dentaire en zone irradiée (niveau de preuve B; aucune nouvelle donnée). II. Indications recommandées en 1re intention de traitement: Accidents de décompression (niveau de preuve C) Embolie gazeuse artérielle ou veineuse compliquée (niveau de preuve C; aucune nouvelle donnée). III. Indications recommandées en 2e ou en 3e intention de traitement: Intoxication au monoxyde de carbone (niveau de preuve B) Gangrène gazeuse (niveau de preuve C; aucune nouvelle donnée). Nécroses infectieuses autres que la gangrène gazeuse (niveau de preuve C; aucune nouvelle donnée) Ostéoradionécrose mandibulaire, radionécrose des tissus mous et des greffes musculocutanées après une chirurgie majeure en zone irradiée, rectite hémorragique postradique (niveau de preuve B) et cystite hémorragique postradique (niveau de preuve C; aucune nouvelle donnée) Plaies réfractaires (lésions diabétiques, ulcères veineux de jambes) (niveau de preuve B) Greffes cutanées et musculocutanées en zone ischémique (niveau de preuve B; aucune nouvelle donnée) Ostéomyélite réfractaire (niveau de preuve C) Abcès intracrânien (niveau de preuve C) Lésions ischémiques et traumatiques : lésions par écrasement, syndrome compartimental et autres traumatismes ischémiques aigus (niveau de preuve B; aucune nouvelle donnée). IV. Indications recommandées en traitement optionnel: Brûlures thermiques (niveau de preuve C; aucune nouvelle donnée) Anémies particulières (niveau de preuve C; aucune nouvelle donnée). Pour la plupart de ces indications, les paramètres d'administration de l'OHB (durée d'exposition optimale, pression, fréquence des séances) restent à confirmer. Enfin, selon l'ECHM, l'OHB peut être un traitement optionnel de la surdité cochléaire soudaine idiopathique dans les premières semaines suivant son apparition (niveau de preuve B). Toutefois, selon la présente évaluation, de nouvelles études sont nécessaires pour justifier le recours systématique à l'OHB pour cette surdité particulière, puisque l'importance clinique des bénéfices obtenus reste incertaine. Pour d'autres affections, les données disponibles ne permettent pas de confirmer l'efficacité de l'OHB : il s'agit des affections malignes, des blessures sportives, du syndrome coronarien aigu, de la chirurgie cardiopulmonaire, des migraines et des céphalées, de la paralysie de Bell, des accidents vasculaires cérébraux et des traumatismes crâniens, et de la sclérose en plaques. Toutefois, le consensus d'experts de l'ECHM précise que l'OHB peut être un traitement optionnel du neuroblastome de stade IV, de la pneumatose kystique de l'intestin et de l'affection ophtalmique ischémique aiguë. Enfin, dans deux rapports récents (2007), l'AETMIS a déjà conclu que l'OHB constitue un traitement expérimental de la paralysie cérébrale et de l'autisme, deux indications aussi non reconnues par les sociétés savantes. Force est de constater que peu d'indications de l'oxygénothérapie hyperbare ont fait l'objet de recherches rigoureuses et que les données probantes sont rares. Il est clair que certaines affections ne se prêtent pas facilement à des recherches pour des raisons éthiques. Les consensus d'experts, bien que non complètement concordants, constituent donc l'assise principale qui appuie et justifie le recours à l'OHB pour une majorité d'indications cliniques. Ces consensus d'experts ouvrent également des avenues intéressantes à de nouvelles recherches de meilleure qualité méthodologique et à des expériences cliniques futures.

INTRODUCTION: During the first half of the 20th century, hyperbaric oxygen (HBO) therapy was used to treat decompression sickness. Other indications have been added over the years, with the result that the Hyperbaric Oxygen Therapy Committee of the Undersea and Hyperbaric Medical Society (UHMS) now recommends HBO therapy for the prevention or treatment of the following 13 conditions: 1) decompression sickness; 2) gas embolism; 3) carbon monoxide poisoning; 4) radionecrosis; 5) problem wounds; 6) thermal burns; 7) skin and tissue graft problems; 8) gas gangrene; 9) necrotizing soft-tissue infections; 10) refractory osteomyelitis; 11) intracranial abscess; 12) crush injuries, compartment syndromes and acute traumatic ischemia; and 13); exceptional blood loss anemias. However, with the exception of emergency situations such as decompression sickness and gas embolism, the applications of HBO therapy are still debated in the scientific literature. In this context, the Minister of Health and Social Services asked the Agence d'évaluation des technologies et des modes d'intervention en santé (AETMIS) to review the current state of knowledge concerning the use of HBO therapy to prevent and treat these 13 conditions. More specifically, it would like to know if, since the publication of the report by the Conseil d'évaluation des technologies de la santé (CETS, AETMIS's predecessor) in 2000, new research has yielded any evidence regarding the efficacy of this technology and if other indications could be added to these 13. It will be noted that AETMIS recently produced two reports on the role of HBO therapy in managing cerebral palsy and autism, two indications that are not recognized by the learned societies. RESULTS: The quantitative and qualitative studies published since 2000 on the 13 indications and a few other conditions treated with HBO therapy were analyzed. With regard to the treatment of idiopathic sudden sensorineural hearing loss, the current knowledge indicates that HBO therapy would significantly reduce hearing loss during the first few weeks following its occurrence. However, the clinical importance of this gain is uncertain and cannot, therefore, justify, at this time, the systematic use of HBO therapy without the support of new studies. However, the ECHM's experts maintain the 1994 recommendation, which advises the use of HBO therapy to treat this condition, until an ongoing European study on this matter is completed. Lastly, the role of HBO therapy in managing cerebral palsy and autism is exhaustively examined in two recent AETMIS reports (2007). Based on the current state of knowledge, these applications are still experimental, and rigorous controlled clinical trials are needed to demonstrate their efficacy. CONCLUSION: The main objective of this report was to update the previous report (published by CETS in 2000) on the recognized indications for hyperbaric oxygen (HBO) therapy. Given the paucity of new studies and the fact that a number of them are of poor quality, AETMIS has, to a large extent, based its assessment on expert consensus, the two main ones being from the Hyperbaric Oxygen Therapy Committee of the Undersea and Hyperbaric Medical Society (UHMS) and the European Committee for Hyperbaric Medicine (ECHM). At the end of its assessment, AETMIS concludes that, on the whole, the recommended indications for hyperbaric oxygen therapy remain the same, although there is now additional information. Based on the evidence (classified into three levels: A - high; B - medium; C - low), the list of indications is now as follows: I. Recommended indication for prevention: Osteoradionecrosis after tooth extraction in an irradiated area (level of evidence: B; no new data). II. Recommended indications as first-line therapy: Decompression sickness (level of evidence: C). Complicated venous or arterial gas embolism (level of evidence: C; no new data). III. Recommended indications as second- or third-line therapy: Carbon monoxide poisoning (level of evidence: B). Gas gangrene (level of evidence: C; no new data). Infectious necroses other than gas gangrene (level of evidence: C; no new data). Mandibular osteoradionecrosis, radionecrosis of soft tissues and musculocutaneous grafts after major surgery in an irradiated area, hemorrhagic radiation rectitis (level of evidence: B) and hemorrhagic radiation cystitis (level of evidence: C; no new data). Problem wounds (diabetic lesions, venous leg ulcers) (level of evidence: B). Skin and musculocutaneous grafts in ischemic areas (level of evidence: B; no new data). Refractory osteomyelitis (level of evidence: C). Intracranial abscess (level of evidence: C). Ischemic and traumatic lesions: crush injuries, compartment syndromes and other acute traumatic ischemia (level of evidence: B; no new data). IV. Recommended indications as optional therapy: Thermal burns (level of evidence: C; no new data). Specific anemias (level of evidence: C; no new data). For most of these indications, the parameters for administering HBO therapy (optimum duration of exposure, pressure, frequency of sessions) have yet to be determined. Lastly, according to the ECHM, HBO therapy can be an optional treatment modality for idiopathic sudden sensorineural hearing loss during the first few weeks following its occurrence (level of evidence: B). However, according to this assessment report, new studies are required in order to justify the systematic use of HBO therapy for this particular type of hearing loss, since the clinical importance of the benefits that it confers is uncertain. For other conditions, it cannot be established from the available evidence that HBO therapy is effective. They are malignant conditions, sports injuries, acute coronary syndrome, cardiopulmonary surgery, migraine, Bell's palsy, head injury, stroke and multiple sclerosis. However, the ECHM expert consensus states that HBO therapy may be an optional treatment for stage IV neuroblastoma, pneumatosis cystoides intestinalis, and acute ischemic ophthalmological disorders. Lastly, in two recent reports (2007), AETMIS concludes that HBO therapy is an experimental treatment for cerebral palsy and autism, two indications that are also not recognized by the learned societies. It should be noted that few indications for hyperbaric oxygen therapy have been rigorously studied and that the evidence is scarce. Obviously, for ethical reasons, certain conditions are not easily amenable to scientific research. Although they are not entirely concordant, the expert consensus are thus the main foundation for supporting and justifying the use of HBO therapy for most of the clinical indications. These expert consensuses are also opening up interesting avenues for new studies of better methodological quality and future clinical experiments.

[A critical assessment of Trendelenburg's position in the acute phase after a diving accident]. / Kritische Beurteilung der Trendelenburg-Lagerung in der akuten Phase nach dem Tauchunfall.

For several years now, a controversy has developed on how to position a patient after a decompression accident with acute gas embolism. The usefulness of the so-called Trendelenburg position, based on experimental evidence gathered on dogs, has recently been challenged. The basis assumption was that cerebral embolism may be reduced by the hydrostatic effect of putting the head below the body's center of gravity. This position however required much technical resourcefulness and often delayed the first therapeutic intervention. Newer experimental research shows that, contrary to the old theory, positioning the head below feet level increases the intra-cranial pressure, injuring the blood-brain barrier, even when done under hyperbaric oxygen therapy. A wide consensus has now emerged, which should be communicated to first-aid personnel, so that no more time is being lost in trying to position the accidented diver by unduly complicated means. The current recommendations asks for laying the injured diver horizontally on its back, or sideways, if he is unconscious. It is by far more important to control its vital functions, give first-aid, administer oxygen in closed circuit, and shorten as much as possible transport time to the next center for hyperbaric therapy.

Uses of hyperbaric oxygen therapy in the 1990s.

Hyperbaric oxygen can produce a variety of effects in addition to reducing air and gas embolism. It increases the killing ability of leukocytes and is lethal to certain anaerobic bacteria. It inhibits toxin formation by certain anaerobes, increases the flexibility of red cells, reduces tissue edema, preserves intracellular adenosine triphosphate, maintains tissue oxygenation in the absence of hemoglobin. In addition, it stimulates fibroblast growth, increases collagen formation, promotes more rapid growth of capillaries, and terminates lipid peroxidation. These actions of hyperbaric oxygen are useful in treating anaerobic infections that result in gas gangrene, as well as severe aerobic infections such as necrotizing fasciitis, malignant external otitis, and chronic refractory osteomyelitis. Hyperbaric oxygen can help preserve ischemic tissues and facilitates the rapid spread and arborization of new capillaries. It promotes healing in certain problem wounds. Adjunctive hyperbaric oxygen treatment is a new approach to the management of radionecrosis. Hyperbaric oxygen treatment reduces morbidity and mortality resulting from carbon monoxide poisoning. Protocols for hyperbaric oxygen therapy are at present mostly empirical; much additional research is needed to better define therapeutic indications.

Hyperbaric oxygen use. Update 1984.

The fact that as many as 60 new hyperbaric oxygen chambers are being established each year in the United States indicates the extent of interest in this relatively new therapy. In 1983 the Hyperbaric Medicine Committee of the Undersea Medical Society revised its classification of conditions being treated by hyperbaric oxygen (HBO), dividing them into two categories: category 1, conditions for which HBO treatment is known to be effective and is third-party reimbursable, and category 2, conditions for which such treatment is unproved experimentally or clinically and is not reimbursable. In the future many of the conditions in category 2 may be reclassified as category 1, which would allow HBO treatment to be third-party reimbursable.

Experimental coronary air embolism. Assessment of time course of myocardial ischemia and the protective effect of cardiopulmonary bypass.

In 74 mongrel dogs 0.02 ml air/kg of body weight was injected into the left anterior descending coronary artery (LAD). Forty-three dogs were studied without (group I) and 31 with (group II) extracorporeal circulation (ECC). Time course and extent of myocardial ischemia were assessed by continous thermographic measurements as well as by fluorescence techniques. Coronary air embolism resulted in an immediate decrease of myocardial temperature associated with transmural ischemia. In 31 surviving dogs (72%) of group I this phenomenon was fully reversible within 8.7 minutes as compared with 5.4 minutes in 100% of the surviving dogs from group II. No postembolic death occurred in the group II animals. In group II the postembolic temperature decrease was significantly less than that in group I, and, in addition, the myocardial area involved was significantly smaller. The results indicate that the extent of myocardial ischemia following coronary air embolism and its time course can be well-documented by means of thermocardiography; using extracorporeal circulation survival can be improved and myocardial damage minimized.