The effect of intravenous perfluorocarbon emulsions on whole-body oxygenation after severe decompression sickness.

Introduction: Decompression sickness (DCS) results from a decrease in ambient pressure leading to supersaturation of tissues with inert gas and bubble formation. Perfluorocarbons (PFCs) are able to dissolve vast amounts of non-polar gases. Intravenous (IV) PFC emulsions reduce both morbidity and mortality associated with DCS, but the mechanism of this protective effect has not yet been demonstrated.

Tissue oxygenation and microvascular hemodynamics in experimental arterial gas embolism.

Microvascular hemodynamic responses to arterial gas embolism (AGE) and local oxygen tensions (PO2) have never been evaluated in vivo using intravital microscopy. A system was implemented to study AGE in real time using brightfield and phosphorescence microscopy as well as laser-induced microvessel occlusion. Bubble dynamics, microhemodynamics and oxygenation were studied following AGE in 61 microvessels and 41 interstitial spaces from 19 anesthetized rats.

Modulation of traumatic brain injury using progesterone and the role of glial cells on its neuroprotective actions.

TBI is a complex disease process caused by a cascade of systemic events. Attention is now turning to drugs that act on multiple pathways to enhance survival and functional outcomes. Progesterone has been found to be beneficial in several animal species, different models of brain injury, and in two preliminary human clinical trials.

The two faces of Eve: gaseous anaesthesia and inert gas narcosis.

Gaseous anaesthesia has been a great boon for medicine. These drugs form a foundation from which modern surgery has sprung, yet their mechanism(s) of actions remains poorly understood. Inert gas narcosis is a limitation of deep sea diving, and its mechanisms also remain poorly understood.

Oxygen transport characterization of a human model of progressive hemorrhage.

Background: Hemorrhage continues to be a leading cause of death from trauma sustained both in combat and in the civilian setting. New models of hemorrhage may add value in both improving our understanding of the physiologic responses to severe bleeding and as platforms to develop and test new monitoring and therapeutic techniques. We examined changes in oxygen transport produced by central volume redistribution in humans using lower body negative pressure (LBNP) as a potential mimetic of hemorrhage.

Current practice, demographics, and trends of critical care trained emergency physicians in the United States.

Objectives: Critical care medicine (CCM) is of growing interest among emergency physicians (EPs), but the number of CCM-trained EPs and their postfellowship practice is unknown. This study's purpose was to conduct a descriptive census survey of EPs who have completed or are currently in a CCM fellowship.

Methods: The authors created a Web-based survey, and requests to participate were sent to EPs who have completed or are currently in a CCM fellowship.

Early physiologic responses to hemorrhagic hypotension.

The identification of early indicators of hemorrhagic hypotension (HH) severity may support early therapeutic approaches and bring insights into possible mechanistic implications. However, few systematic investigations of physiologic variables during early stages of hemorrhage are available. We hypothesized that, in certain subjects, early physiologic responses to blood loss are associated with the ability to survive hemorrhage levels that are lethal to subjects that do not present the same responses.

Severe hypocholesterolemia in surgical patients, sepsis, and critical illness.

After surgery, in sepsis and various critical illnesses, factors such as severity of the acute phase response, liver dysfunction, and hemodilution from blood loss have cumulative impacts in decreasing cholesterol; therefore, degree of hypocholesterolemia often reflects severity of illness. The direct correlation between cholesterol and several plasma proteins is mediated by the parallel impact of commonly shared determinants. Cholestasis is associated with a moderation of the degree of hypocholesterolemia.

Androstenediol reverses steroid-inhibited wound healing.

It is well recognized that stress of any nature will cause a delay in the wound healing response. This delayed healing response appears closely associated with immune regulators. In this study, CD-1 mice were injected with a long acting form of methyl prednisolone to cause a steroid-induced immune suppression.

Perfluorocarbon emulsions as a promising technology: a review of tissue and vascular gas dynamics.

Perfluorocarbon (PFC) emulsions are halogen-substituted carbon nonpolar oils with resultant enhanced dissolved respiratory gas (O(2), N(2), CO(2), nitric oxide) capabilities. In the first demonstration of enhanced O(2) solubility, inhaled PFC could sustain rat metabolism. Intravenous emulsions were then trialed as "blood substitutes.

Plasma bilirubin correlations in non-obstructive cholestasis after partial hepatectomy.

Background: The aim of this study was to provide an improved outline of the patterns and correlates of changes in plasma bilirubin after partial hepatectomy.

Methods: A large series of blood measurements and complementary variables were prospectively collected from 85 patients undergoing liver resection, and bilirubin correlations were assessed by regression analysis.

Results: Early postoperatively, the best simultaneous correlates of increasing bilirubin were the preoperative value, the duration of surgery, and the number of blood transfusions (r2 = 0.

Comparisons of high versus low emergency department utilizers in sickle cell disease.

Study Objective: Patients with sickle cell disease often receive a substantial amount of their health care in the emergency department (ED) and some come to the ED frequently, seeking treatment for pain. As a result, patients with sickle cell disease are often stigmatized as opioid-seeking ED overutilizers. We describe the proportion of sickle cell disease patients who are high utilizers of the ED and compare them with other sickle cell disease patients on demographics, pain characteristics, health data, psychosocial characteristics, and quality of life.

Effects of perfluorocarbon infusion in an anesthetized swine decompression model.

Introduction: Decompression illness (DCI) results from sudden changes in ambient pressure leading to super-saturation and bubble formation in tissues and the blood stream. Perfluorocarbon emulsions (PFC) increase both oxygen and nitrogen solubility when infused into the blood stream. This study hypothesized that PFC would increase N(2) removal as well as O(2) delivery to tissues.

Treating heparin resistance with antithrombin or fresh frozen plasma.

Heparin resistance occurs in up to 22% of patients undergoing cardiac surgery requiring cardiopulmonary bypass and it is associated with decreased levels of antithrombin. Treatment options for heparin resistance include administration of antithrombin or fresh frozen plasma. A systematic review revealed no clinical trials directly comparing antithrombin with fresh frozen plasma as heparin resistance treatment during cardiopulmonary bypass.

Dyslipidemia can reduce the immunosuppressive effects of cyclosporine.

Aims: Dyslipidemia is a significant risk factor for the development of atherosclerotic disease and of chronic allograft rejection. Few data are available on the effects of dyslipidemia on the immunosuppressive action of immunosuppressive agents. We investigate the in vitro effects of lipids solution on the immunosuppressive action of cyclosporine (CsA).

Androstenetriol immunomodulation improves survival in a severe trauma hemorrhage shock model.

Background: Traumatic shock activates the hypothalamic-pituitary-adrenal axis (HPA) to mediate a cascade of defensive mechanisms that often include overwhelming inflammatory response and immunosuppression, which may lead to multiple organ failure. Androstenetriol (5 androstene, 3beta, 7beta, 17beta triol-AET) is a metabolite of dehydroepiandrosterone that markedly up regulates host immune response, prevents immune suppression, modulates inflammation and improves survival after lethal infections by pathogens and lethal radiation.

Hypothesis: AET-induced immune modulation will improve survival in a conscious rodent model of traumatic shock.

Comparison of a new hemostatic agent to current combat hemostatic agents in a Swine model of lethal extremity arterial hemorrhage.

Background: Gaining hemostatic control of lethal vascular injuries sustained in combat using topical agents remains a challenge. Recent animal testing using a lethal arterial injury model has demonstrated that QuikClot zeolite granules (QCG) and the HemCon chitosan bandage (HC) are not capable of providing hemostasis and improving survival over the Army gauze field bandage (AFB). We have developed a new hemostatic agent consisting of a granular combination of a smectite mineral and a polymer (WoundStat) capable of producing hemostasis in the face of high-pressure arterial bleeding.

Low-volume resuscitation cocktail extends survival after severe hemorrhagic shock.

After severe hemorrhage, low-volume resuscitation with hypertonic fluids is increasingly preferred to more aggressive resuscitation strategies. Oxygen delivery to the tissues may be improved by augmentation with hemoglobin [Hb]-based oxygen-carrying compounds (HBOCs); however, previous studies have reported negative outcomes presumably related to extravasation of tetrameric Hb. The purpose of this study was to evaluate a novel large molecular weight polymer of cross-linked bovine Hb (OxyVita; OXYVITA Inc, New Windsor, NY) in a cocktail of hypertonic saline and Hextend (HX; HBOC-C) as an alternative to standard small-volume resuscitation using Hextend (HX) only.

Intravenous perfluorocarbon emulsion increases nitrogen washout after venous gas emboli in rabbits.

Intravenous perfluorocarbon emulsion (IV-PFC) has been shown to provide hemodynamic protection from gas embolism (Venous-VGE or arterial-AGE). The objective of this study was to investigate the mechanism of PFC protection from controlled VGE by quantifying the effects of IV-PFC emulsion on pulmonary elimination of nitrogen (N2). All rabbits received an intravenous pretreatment of PFC emulsion (Oxygent, 2.

Impaired wound healing.

Nonhealing wounds represent a significant cause of morbidity and mortality for a large portion of the population. One of the underlying mechanisms responsible for the failure of chronic wounds to heal is an out-of-control inflammatory response that is self-sustaining. Underappreciation of the inherent complexity of the healing wound has led to the failure of monotherapies, with no significant reduction in wound healing times.

Androstenetriol improves survival in a rodent model of traumatic shock.

Unlabelled: Trauma results in activation of the hypothalamic-pituitary-adrenal axis to mediate a cascade of neurohormonal changes as a defensive mechanism. Its prolongation, however, leads to a hypermetabolic, hypoperfused, and immunosuppressed state, setting the stage for subsequent sepsis and organ failure. Androstenetriol (5-androstene-3beta, 7beta, 17betatriol - AET), a metabolite of dehydroepiandrosterone, up-regulates the host immune response markedly, prevents immune suppression and controls inflammation, leading to improved survival after lethal infections by several diverse pathogens and lethal radiation.

A new noninvasive method to determine central venous pressure.

Unlabelled: Knowledge of central venous pressure (CVP) is considered valuable in the assessment and treatment of various states of critical illness and injury.

Objectives: We tested a noninvasive means of determining CVP (NICVP), by monitoring forearm volume changes in response to externally applied circumferential pressure to the upper arm veins.

Methods: Sixteen patients who were undergoing CVP monitoring as a part of their care had NICVP determined and compared with CVP.

Decreased supply-dependent oxygen consumption in the skeletal muscle of the spontaneously hypertensive rat during acute hypoxia.

The purpose of this study was to correlate microvascular oxygen delivery (DO2) and consumption (VO2) in the skeletal muscle of spontaneously hypertensive rats (SHRs) and Wistar Kyoto rats (WKY) with hemodynamics during acute hypoxia. We expected greater abnormalities in central and microvascular hemodynamics during hypoxic induced shock in the SHR compared with the WKY due to microvascular rarefaction. The inspired oxygen fraction (FiO2) was lowered from 0.

Resonance Raman spectroscopy: a new technology for tissue oxygenation monitoring.

Objective: To evaluate resonance Raman spectroscopy for the detection of changes in sublingual mucosal hemoglobin oxygen saturation (Smo2) in response to hemorrhage and resuscitation, and to compare Smo2 with other indicators of tissue oxygenation including central venous oxygen saturation (Scvo2), lactate, base excess, and shed blood volume.

Design: Prospective single group pilot study.

Setting: University laboratory.