Resuscitation
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The effects of Dextran 70 with NaCl as against Ringer's acetate on hemodynamics, gas exchange, oxygen transport and survival were evaluated in a porcine model of pulmonary and circulatory insufficiency induced by a continuous i.v. endotoxin infusion over 6 h. Dextran and Ringer's acetate were infused continuously to maintain baseline mean left atrial pressure (MLAP) throughout the endotoxin period. Twelve pigs receiving endotoxin + Ringer's acetate displayed a progressive 45% decline in cardiac output (Qt) and a two peaked increase in pulmonary vascular resistance (PVR) with a late increase of 250%. ⋯ PMNs were significantly increased compared with the Ringer's group. The amount of Ringer's acetate necessary to maintain a stable MLAP averaged 4.6 times the Dextran volume. The superiority of Dextran as compared with Ringer's acetate in this endotoxemic shock model seems to be consequent to better rheological effects combined with pharmacological interactions with granulocytes.
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Eight sheep, weighing 29-71 kg, were used to evaluate the cardiopulmonary response to Hespan infusion following shock. Before shock was induced, mean arterial pressure (MAP), pulmonary capillary wedge pressure (PCWP), pulmonary artery pressure (PAP), cardiac output (CO), extravascular lung water (EVLW), colloid oncotic pressure (COP), and hemoglobin were measured and shunt, arteriovenous oxygen content difference (C[a - v]O2) and COP-PCWP gradient were calculated. The animals were bled to a MAP of 50 mmHg and that level was maintained for 30 min. ⋯ C(a - v)O2 returned to baseline with resuscitation. Volume of hetastarch infused was 29.1 +/- 10 cm3/kg. We conclude that hetastarch is an effective resuscitation solution in a model of hemorrhagic shock and appears to have no adverse cardiopulmonary effects.
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Two cases are presented of pulmonary barotrauma developing during cardiopulmonary resuscitation. This was attributed to high airway pressures developed during ventilation. One patient was ventilated with a self-inflating bag and the second with the Robertshaw demand valve. ⋯ Three other cases of pulmonary barotrauma during resuscitation have been recorded with the use of the latter device during CPR by ambulance personnel in Israel. The Robertshaw demand valve may generate excessively high airway pressures during normal use or when malfunctioning. For these reasons, the use of the Robertshaw demand valve has been discontinued in the Israeli Emergency Medical Services ambulances.
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Reported here is the case of a patient suffering from hemodynamically significant bradycardia in which the use of transcutaneous cardiac pacing resulted in successful resuscitation, obviating the need for invasive pacing. During pacing, intra-arterial recordings of blood pressure demonstrated higher pulse pressures for paced beats than for the patient's own escape beats. Recent data regarding the use of non-invasive transcutaneous cardiac pacing is also reviewed.
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Recent studies have shown the potential adverse effects of venous volume loading on blood flow during closed chest cardiopulmonary resuscitation (CPR). To examine the effect of arterial and venous infusions, we employed a published computer simulation of the circulation during CPR. This model uses computer simulated electrical networks to model the heart and great vessels. ⋯ Rise and fall times for initiation and cessation of flow augmentations were equal to four compression cycles. We conclude that these findings demonstrate the theoretical benefits of rapid arterial infusions during CPR with increases in myocardial and cranial blood flow. This method may provide an early temporary adjunct to myocardial perfusion during CPR.