Anette C. Krismer

Vasopressin During Cardiopulmonary Resuscitation and Different Shock States

Vasopressin administration may be a promising therapy in the management of various shock states. In laboratory models of cardiac arrest, vasopressin improved vital organ blood flow, cerebral oxygen delivery, the rate of return of spontaneous circulation, and neurological recovery compared with epinephrine (adrenaline). In a study of 1219 adult patients with cardiac arrest, the effects of vasopressin were similar to those of epinephrine in the management of ventricular fibrillation and pulseless electrical activity; however, vasopressin was superior to epinephrine in patients with asystole. Furthermore, vasopressin followed by epinephrine resulted in significantly higher rates of survival to hospital admission and hospital discharge. The current cardiopulmonary resuscitation guidelines recommend intravenous vasopressin 40IU or epinephrine 1mg in adult patients refractory to electrical countershock. Several investigations have demonstrated that vasopressin can successfully stabilize hemodynamic variables in advanced vasodilatory shock. Use of vasopressin in vasodilatory shock should be guided by strict hemodynamic indications, such as hypotension despite norepinephrine (noradrenaline) dosages >0.5βlg/kg/min. Vasopressin must never be used as the sole vasopressor agent. In our institutional routine, a fixed vasopressin dosage of 0.067 IU/min (i.e. 100 IU/50mL at 2 mL/h) is administered and mean arterial pressure is regulated by adjusting norepinephrine infusion. When norepinephrine dosages decrease to 0.2βg/kg/min, vasopressin is withdrawn in small steps according to the response in mean arterial pressure. Vasopressin also improved short-and long-term survival in various porcine models of uncontrolled hemorrhagic shock. In the clinical setting, we observed positive effects of vasopressin in some patients with life-threatening hemorrhagic shock, which had no longer responded to adrenergic catecholamines and fluid resuscitation. Clinical employment of vasopressin during hemorrhagic shock is experimental at this point in time.

Vasopressin improves survival in a porcine model of abdominal vascular injury

IntroductionWe sought to determine and compare the effects of vasopressin, fluid resuscitation and saline placebo on haemodynamic variables and short-term survival in an abdominal vascular injury model with uncontrolled haemorrhagic shock in pigs.MethodsDuring general anaesthesia, a midline laparotomy was performed on 19 domestic pigs, followed by an incision (width about 5 cm and depth 0.5 cm) across the mesenterial shaft. When mean arterial blood pressure was below 20 mmHg, and heart rate had declined progressively, experimental therapy was initiated. At that point, animals were randomly assigned to receive vasopressin (0.4 U/kg; n = 7), fluid resuscitation (25 ml/kg lactated Ringers and 25 ml/kg 3% gelatine solution; n = 7), or a single injection of saline placebo (n = 5). Vasopressin-treated animals were then given a continuous infusion of 0.08 U/kg per min vasopressin, whereas the remaining two groups received saline placebo at an equal rate of infusion. After 30 min of experimental therapy bleeding was controlled by surgical intervention, and further fluid resuscitation was performed. Thereafter, the animals were observed for an additional hour.ResultsAfter 68 ± 19 min (mean ± standard deviation) of uncontrolled bleeding, experimental therapy was initiated; at that time total blood loss and mean arterial blood pressure were similar between groups (not significant). Mean arterial blood pressure increased in both vasopressin-treated and fluid-resuscitated animals from about 15 mmHg to about 55 mmHg within 5 min, but afterward it decreased more rapidly in the fluid resuscitation group; mean arterial blood pressure in the placebo group never increased. Seven out of seven vasopressin-treated animals survived, whereas six out of seven fluid-resuscitated and five out of five placebo pigs died before surgical intervention was initiated (P < 0.0001).ConclusionVasopressin, but not fluid resuscitation or saline placebo, ensured short-term survival in this vascular injury model with uncontrolled haemorrhagic shock in sedated pigs.

Die Behandlung des hämorrhagischen Schocks

ZusammenfassungDer hämorrhagische Schock wird mit Gegenregulationsmechanismen des Organismus beantwortet, die zumindest ein temporäres Überleben ermöglichen. Hier können neue Therapiestrategien ansetzen. Die Zukunft der Schockbehandlung wird vom wissenschaftlichen Erkenntnisgewinn und der Bereitschaft der Ärzte abhängen, etablierte Therapiekonzepte zu aktualisieren. Die vierxa0Hauptzielgrößen der zukünftigen Schockbehandlung sind: Blutungskontrolle durch lokale blutstillende Maßnahmen und eine Optimierung des Gerinnungssystems; Erhöhung des intravaskulären Volumens durch Ausschöpfung venöser Blutreserven (Vermeidung von Fehlern bei der kontrollierten Beatmung, Einsatz alternativer Spontan- bzw. Beatmungskonzepte, Infusion von künstlichen Sauerstoffträgern); pharmakologische Interaktion mit endogenen Kompensations- und Dekompensationsmechanismen (Gabe von Arginin-Vasopressin und ATP-sensitiven Kalium-Kanal-Blockern); Anwendung protektiver Maßnahmen (Induktion einer moderaten Hypothermie). Ultimative Zukunftsvision in der Behandlung des vital bedrohlichen hämorrhagischen Schocks ist die „suspended animation“ im Sinne einer postponierten Wiederbelebung nach Protektion vitaler Organsysteme.AbstractThe future of shock treatment depends on the importance of scientific results, and the willingness of physicians to optimize, and to reconsider established treatment protocols. There are four major potentially promising approaches to advanced trauma life support. First, control of hemorrhage by administration of local hemostatic agents, and a better, target-controlled management of the coagulation system. Second, improving intravascular volume by recruiting blood from the venous vasculature by preventing mistakes during mechanical ventilation, and by employing alternative spontaneous (i.e. use of the inspiratory threshold valve) or artificial ventilation strategies. In addition, artificial oxygen carriers may improve intravascular volume and oxygen delivery. Third, pharmacologic support of physiologic, endogenous mechanisms involved in the compensation phase of shock, and blockade of pathomechanisms that are known to cause irreversible vasoplegia (arginine vasopressin and KATP channel blockers for hemodynamic stabilization). Fourth, employing potentially protective strategies such as mild or moderate hypothermia. Finally, the ultimate vision of trauma resuscitation is the concept of “suspended animation” as a form of delayed resuscitation after protection of vital organ systems.

Extended hepatic resection and portosystemic shunt in pigs: a model for experimental liver regeneration

ZusammenfassungGRUNDLAGEN: Die Leberresektion ist eine chirurgisch herausfordernde, aber sicherlich die beste Methode für das Studium der Leberregeneration. Nachdem die Schweineleber eine der humanen Leber vergleichbare Größe, Form und Segmentanatomie hat, wurde eine Technik mit erweiterter Leberresektion und Anlage eines portosystemischen Shunts für das Studium einer Reihe resektionsbedingter Probleme, allen voran der portalen Hyperperfusion, entwickelt. METHODIK: Bei 16 Schweinen wurde eine erweiterte Hemihepatektomie links (etwa 75 % des Lebervolumens) durchgeführt, wobei bei 8 Tieren die Resektion nach Anlage eines portosystemischen H-Shunts zwischen Pfortader und Vena cava erfolgte. Laborproben, Leberbiopsien und Duplexsonografien der Lebergefäße wurden regelmäßig bis zum 8. postoperativen Tag durchgeführt, und die Tiere bis zu ihrem Ableben beobachtet. ERGEBNISSE: Keines der Tiere ist an einer chirurgischen Komplikation verstorben. Obwohl in der Shuntgruppe der Pfortaderfluss reduziert und die arterielle Durchblutung gesteigert war, war die Regeneration der Leber (Restlebervolumen zum Zeitpunkt der Kontrolle / Restlebervolumen nach Resektion) in beiden Gruppen hoch. Nach initialen Leberzellnekrosen zeigten die Biopsien histologisch am Ende der Beobachtungsphase normales Lebergewebe, unabhängig von der Anlage eines Shunts. SCHLUSSFOLGERUNGEN: Diese Technik der erweiterten Leberresektion mit und ohne Anlage eines portosystemischen Shunts ist hilfreich für die Untersuchung der Hämodynamik und der Leberregeneration, insbesondere im Lanzeitverlauf.SummaryBACKGROUND: Liver resection is an extremely demanding procedure, but is considered the best model for studying liver regeneration. Since the porcine liver has a comparable size, external morphology and segmental anatomy to the human liver, we designed a surgical technique for extended hepatectomy and portosystemic shunt in pigs as a model for the study of various resection-related problems, in particular portal hyperperfusion. METHODS: A seventy-five percent hepatectomy was performed on sixteen pigs, as well as on eight pigs after construction of a side-to-side portocaval H-shunt. Blood samples, liver biopsies and hemodynamic ultrasound examinations were monitored regularly up to day 8 after resection and the animals observed until their death or sacrifice on day 19. RESULTS: None of the pigs died as a result of surgical complications. Although portal blood flow was decreased and arterial flow increased in the pigs with shunt, regeneration rate (remnant liver volume at follow-up/remnant liver volume after surgery) was high in both groups. After initial liver necrosis, survivors showed histologically normal liver tissue around day 19 irrespective of portocaval shunt. CONCLUSIONS: This technique of extended liver resection in the porcine model, with or without portosystemic shunt, may be useful for hemodynamic and liver regeneration studies, in particular for long-term results.

The axillocoronary bypass – an exotic but useful conduit in coronary surgery

ZusammenfassungGRUNDLAGEN: Der axillokoronare Bypass ist eine extraanatomische Bypassgraft-Variante, welche dann indiziert ist, wenn eine Resternotomie oder ein Bypass-Anschluss an die Aorta ascendens vermieden werden sollen. METHODIK: Üblicherweise wird ein Vena saphena magna graft verwendet, die Arteria radialis stellt aber auch eine mögliche Option dar. Speziell sollte auf einen spannungsfreien Verlauf in der Regio infraclavicularis, auf eine weite Öffnung des interkostalen Durchtritts sowie auf eine Platzierung in der Pleurahöhle, welche eine Einklemmung oder Kompression durch die Lunge verhindert, geachtet werden. ERGEBNISSE: Bypass flows und Flow Profile scheinen adäquat zu sein. Ebenso sind die in der Literatur berichtete perioperative Letalität und frühe Bypass-Offenheitsrate zufriedenstellend. Einzelfälle von durchgängigen axillokoronaren Bypassgrafts nach 5 bis 8 Jahren sind bekannt. SCHLUSSFOLGERUNGEN: Mehr Information über die Bypassdurchgängikeit muss angesammelt werden um die Langzeit-haltbarkeit zu beurteilen.SummaryBACKGROUND: The axillocoronary bypass graft is an extraanatomical coronary bypass graft variation that is indicated when sternal reentry or proximal graft connection to the ascending aorta need to be avoided. METHODS: Usually a saphenous vein graft is taken but for the axillary artery to left anterior descending artery position the radial artery is also an option. Special attention should be paid to a tension free course in the infraclavicular region, a wide opening of the intercostal transition, and placement of the graft in the pleural space that avoids entrapment or compression by the lung. RESULTS: Graft flows and profiles seem to be adequate and hospital mortality as well as early graft patency in the literature are acceptable. Single cases with promising graft patency in the 5–8 year range are currently available. CONCLUSIONS: More information on longterm patency needs to be accumulated in order to assess the durability of the axillocoronary bypass graft.

Die Behandlung des hämorrhagischen Schocks@@@Treatment of hemorrhagic shock: Neue Therapieoptionen@@@New therapy options

ZusammenfassungDer hämorrhagische Schock wird mit Gegenregulationsmechanismen des Organismus beantwortet, die zumindest ein temporäres Überleben ermöglichen. Hier können neue Therapiestrategien ansetzen. Die Zukunft der Schockbehandlung wird vom wissenschaftlichen Erkenntnisgewinn und der Bereitschaft der Ärzte abhängen, etablierte Therapiekonzepte zu aktualisieren. Die vierxa0Hauptzielgrößen der zukünftigen Schockbehandlung sind: Blutungskontrolle durch lokale blutstillende Maßnahmen und eine Optimierung des Gerinnungssystems; Erhöhung des intravaskulären Volumens durch Ausschöpfung venöser Blutreserven (Vermeidung von Fehlern bei der kontrollierten Beatmung, Einsatz alternativer Spontan- bzw. Beatmungskonzepte, Infusion von künstlichen Sauerstoffträgern); pharmakologische Interaktion mit endogenen Kompensations- und Dekompensationsmechanismen (Gabe von Arginin-Vasopressin und ATP-sensitiven Kalium-Kanal-Blockern); Anwendung protektiver Maßnahmen (Induktion einer moderaten Hypothermie). Ultimative Zukunftsvision in der Behandlung des vital bedrohlichen hämorrhagischen Schocks ist die „suspended animation“ im Sinne einer postponierten Wiederbelebung nach Protektion vitaler Organsysteme.AbstractThe future of shock treatment depends on the importance of scientific results, and the willingness of physicians to optimize, and to reconsider established treatment protocols. There are four major potentially promising approaches to advanced trauma life support. First, control of hemorrhage by administration of local hemostatic agents, and a better, target-controlled management of the coagulation system. Second, improving intravascular volume by recruiting blood from the venous vasculature by preventing mistakes during mechanical ventilation, and by employing alternative spontaneous (i.e. use of the inspiratory threshold valve) or artificial ventilation strategies. In addition, artificial oxygen carriers may improve intravascular volume and oxygen delivery. Third, pharmacologic support of physiologic, endogenous mechanisms involved in the compensation phase of shock, and blockade of pathomechanisms that are known to cause irreversible vasoplegia (arginine vasopressin and KATP channel blockers for hemodynamic stabilization). Fourth, employing potentially protective strategies such as mild or moderate hypothermia. Finally, the ultimate vision of trauma resuscitation is the concept of “suspended animation” as a form of delayed resuscitation after protection of vital organ systems.