Cardiopulmonary resuscitation: when guidelines provide no answers.

Out of hospital cardiac arrest (OHCA) is encountered on a regular basis in prehospital care. Specific guidelines exist for cardiopulmonary resuscitation. Guidelines cover most related situations but cannot cover all of them.

Ischemia-reperfusion-induced unmeasured anion generation and glycocalyx shedding: sevoflurane versus propofol anesthesia.

Introduction: Vascular leakage after ischemia-reperfusion (IR) is largely attributed to the destruction of the endothelial barrier and its associated negatively charged glycocalyx. In vitro, sevoflurane attenuates these changes. Therefore, we compared sevoflurane with propofol with regard to the protection of the glycocalyx and the release of negatively charged substances in vivo.

Functional hemodynamic parameters do not reflect volume responsiveness in the immediate phase after acute myocardial ischemia and reperfusion.

Objective: Functional preload parameters such as stroke-volume variation (SVV) and pulse-pressure variation (PPV) are superior to filling pressures when assessing volume responsiveness in mechanically ventilated patients. This investigation studied their application in the setting of acute myocardial ischemia and reperfusion (I/R).

Design And Setting: Experimental animal study in a university laboratory.

Serum heparan sulfate levels are elevated in endotoxemia.

Background: Increased vascular permeability is a characteristic feature of sepsis which, in the past, has been ascribed exclusively to a malfunction of endothelial cells. However, recently it has become evident that the endothelial glycocalyx is of considerable importance concerning various aspects of vascular physiology, e.g.

Does the estimation of light attenuation in tissue increase the accuracy of reflectance pulse oximetry at low oxygen saturations in vivo?

A new technique was validated in vivo in reflectance pulse oximetry for measuring low oxygen saturations. Two pairs of light emitter/detector diodes allow for estimation of light attenuation (LA) in tissue, which is assumed to be responsible for the inaccuracy of pulse oximetry at less than 70 % arterial oxygen saturation. For validation, 17 newborn piglets were desaturated stepwise from 21 % to 1.

Effect of inhaled and intravenous lidocaine on inflammatory reaction in endotoxaemic rats.

Background And Objective: Systemically administered lidocaine has been shown to have anti-inflammatory properties. Inhalation is an attractive way of application because of high pulmonary compound concentrations and potentially fewer systemic side effects. The aim of this study was to clarify whether inhaled or, likewise, intravenous lidocaine can attenuate the inflammatory response in a model of experimental endotoxaemia in the rat.

The initial tangent of the aortic pressure increase is an estimate of left ventricular contractility in pigs.

The aim was, to identify an estimate of left ventricular contractility derived from the aortic pressure wave without load changing manoeuvres. For this purpose, left ventricular contractility was assessed with several aortic pressure wave form derived parameters and was compared to standard parameters of left ventricular contractility (conductance technique) in an experimental study. Measurements were taken during baseline, after beta-stimulation and after injection of a beta-antagonist.

Lung injury following thoracic aortic occlusion: comparison of sevoflurane and propofol anaesthesia.

Background: Halogenated anaesthetics have been shown to reduce ischaemia-reperfusion injuries in various organs due to pre- and post-conditioning mechanisms. We compared volatile and total intravenous anaesthesia with regard to their effect on remote pulmonary injury after thoracic aortic occlusion and reperfusion.

Methods: Eighteen pigs were randomized after sternotomy and laparotomy (fentanyl-midazolam anaesthesia) to receive either sevoflurane or propofol in an investigator-blinded fashion.

Causes of metabolic acidosis in canine hemorrhagic shock: role of unmeasured ions.

Introduction: Metabolic acidosis during hemorrhagic shock is common and conventionally considered to be due to hyperlactatemia. There is increasing awareness, however, that other nonlactate, unmeasured anions contribute to this type of acidosis.

Methods: Eleven anesthetized dogs were hemorrhaged to a mean arterial pressure of 45 mm Hg and were kept at this level until a metabolic oxygen debt of 120 mLO2/kg body weight had evolved.

Positive end-expiratory pressure does not compromise myocardial contractility in myocardial ischemia/reperfusion.

Therapy for severe myocardial ischemia/reperfusion sometimes necessitates intermittent positive pressure ventilation, which may impair left ventricular function by reduction of ventricular loading. It is unknown today whether positive airway pressure also affects contractile force after myocardial ischemia/reperfusion. The authors tested whether positive end-expiratory pressure (PEEP) impairs myocardial contractility in acute ischemic heart failure.

Validation of pulse contour derived stroke volume variation during modifications of cardiac afterload.

Background: Left ventricular stroke volume variation (SVV) or its surrogates are useful tools to assess fluid responsiveness in mechanically ventilated patients. So far it is unknown, how changes in cardiac afterload affect SVV. Therefore, this study compared left ventricular SVV derived by pulse contour analysis with SVV measured using an ultrasonic flow probe and investigated the influence of cardiac afterload on left ventricular SVV.

Effects of sevoflurane and propofol on ischaemia-reperfusion injury after thoracic-aortic occlusion in pigs.

Background: Thoraco-abdominal-aneurysm surgery predicts high mortality. Propofol and sevoflurane are commonly used anaesthetics for this procedure. Halogenated anaesthetics induce organ protection similar to ischaemic preconditioning.

The influence of PEEP and tidal volume on central blood volume.

Background And Objective: Measurement of central blood volumes (CBV), such as global end-diastolic volume (GEDV) and right ventricular end-diastolic volume (RVEDV) are considered appropriate estimates of intravascular volume status. However, to apply those parameters for preload assessment in mechanically ventilated patients, the influence of tidal volume (TV) and positive endexpiratory airway pressure (PEEP) on those parameters must be known.

Methods: In 13 mechanically ventilated piglets, the effect of low (10 mL kg(-1)) and high (20 mL kg(-1)) TVs on CBV was investigated in absence and presence of PEEP (0 and 15 cm H(2)O).

The influence of positive end-expiratory pressure on stroke volume variation and central blood volume during open and closed chest conditions.

Objective: Intermittent positive pressure ventilation and positive end-expiratory pressure (PEEP) affect cardiac preload. Their effect is dependent on chest wall compliance. This study compares the effects of intermittent positive pressure ventilation and PEEP on stroke volume variation and central blood volume during open and closed chest conditions.

Hyperoxic ventilation enables hemodilution beyond the critical myocardial hemoglobin concentration.

Background: When initiated in anemic hypoxia, hyperoxic ventilation (ventilation with pure O2, FiO2 1.0, HV) reverses hypoxia-induced ECG-changes and enables survival for several hours. The quantification of the HV-induced gain in anemia tolerance and particularly the Hb-equivalent of HV in this situation are unknown.

The influence of cardiac preload and positive end-expiratory pressure on the pre-ejection period.

The pre-ejection period (PEP) has recently been described as a potential parameter for monitoring cardiac preload. This study further investigated the influence of changes in intravascular volume status and the application of positive end-expiratory pressure (PEEP) on the pre-ejection period. In ten pigs, ECG, arterial pressure and stroke volume derived from an aortic flowprobe were registered.

Oxygent as a top load to colloid and hyperoxia is more effective in resuscitation from hemorrhagic shock than colloid and hyperoxia alone.

Perfluorocarbon (PFC) emulsions are intravascular oxygen therapeutics that temporarily enhance tissue oxygenation in dilutional anemia. However, PFC emulsions are not resuscitation fluids because PFCs only work optimally in the presence of high O2 partial pressure (hyperoxia); moreover, because they have no oncotic potential, dosing limitations prevent their use to permanently replace large hemorrhage volumes. Our objective was to clarify whether in the presence of hyperoxia a conventional colloid therapy supplemented by PFC is more efficacious than colloid alone.

Effects of perfluorohexan vapor on gas exchange, respiratory mechanics, and lung histology in pigs with lung injury after endotoxin infusion.

Background: Inhaled perfluorohexan vapor has been shown to improve gas exchange and pulmonary mechanics in oleic acid- and ventilator-induced lung injury. However, in the clinical setting, lung injury frequently occurs in the context of systemic inflammation and consecutive lung injury, which may be induced experimentally by intravenous administration of endotoxin. The authors studied whether vaporized perfluorohexan is efficacious during endotoxin-induced lung injury in domestic pigs.

Effect of prostaglandin I2 analogues on left ventricular diastolic function in vivo.

The prostaglandin I2 analogues epoprostenol and iloprost increase left ventricular contractility. Therefore, we hypothesize that the prostaglandin I2 analogues epoprostenol and iloprost improve also left ventricular diastolic function. To test this hypothesis, the effects of epoprostenol and iloprost on left ventricular diastolic function were assessed in vivo and compared to two vasodilators sodium nitroprusside and adenosine, not formerly associated with changes of left ventricular contractility.

Regional blood flow during hyperoxic haemodilution.

Background: Ventilation with pure oxygen (hyperoxic ventilation, HV) increases arterial oxygen content (CaO(2)). However HV induces arteriolar constriction and thus potentially affects O(2) supply. We therefore investigated the effects of HV on regional blood flow (RBF) and O(2) supply of different vital organs during moderate normovolaemic anaemia.

Improved ventricular function during inhalation of PGI(2) aerosol partly relies on enhanced myocardial contractility.

Inhaled prostacyclin (PGI(2)) aerosol induces selective pulmonary vasodilation. Further, it improves right ventricular (RV) function, which may largely rely on pulmonary vasodilation, but also on enhanced myocardial contractility. We investigated the effects of the inhaled PGI(2) analogs epoprostenol (EPO) and iloprost (ILO) on RV function and myocardial contractility in 9 anesthetized pigs receiving aerosolized EPO (25 and 50 ng.

Fluid resuscitation from severe hemorrhagic shock using diaspirin cross-linked hemoglobin fails to improve pancreatic and renal perfusion.

Background: Fluid resuscitation from hemorrhagic shock is intended to abolish microcirculatory disorders and to restore adequate tissue oxygenation. Diaspirin cross-linked hemoglobin (DCLHb) is a hemoglobin-based oxygen carrier (HBOC) with vasoconstrictive properties. Therefore, fluid resuscitation from severe hemorrhagic shock using DCLHb was expected to improve perfusion pressure and tissue perfusion of kidneys and pancreas.

Aerosol delivery during mechanical ventilation to the rat.

The authors have adjusted a jet nebulizer to a mechanical ventilator (Servo Ventilator, Siemens) to deliver an aerosol to rats. They aimed to clarify whether a modified jet nebulizer generating particles with a mass median aerodynamic diameter of 2 microm would be effective and safe in intubated ventilated rats. Fluorescent microspheres (diameter: 1.

Mycoplasma haemocanis infection--a kennel disease?

Mycoplasma haemocanis (formerly Haemobartonella canis) is a red blood cell parasite that causes disease mainly in immunosuppressed and splenectomized dogs. Clinical outbreak of the disease resulted in failure of a large experimental project. We aimed to identify whether M.