Resuscitation
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Comparative Study
Seven years' experience with early defibrillation by police and paramedics in an emergency medical services system.
To assess the outcome of patients with out-of-hospital cardiac arrest with ventricular fibrillation as the presenting rhythm in an emergency medical services system utilizing a combined police/paramedic response to provide early defibrillation. ⋯ Both restoration of a functional circulation, without need for advanced life support interventions, and discharge survival without neurologic disability are very dependent upon the rapidity with which defibrillation is accomplished, regardless of who delivers the shocks. In addition, a smaller but significant number of patients who require ALS interventions, including epinephrine, for restoration of a spontaneous circulation survive to discharge. Short time differences, on the order of 1 min, are significant determinants of both immediate response to shocks and discharge survival.
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Reluctance of the lay public to perform bystander CPR is becoming an increasingly worrisome problem in the USA. Most bystanders who admit such reluctance concede that fear of contagious disease from mouth-to-mouth contact is what keeps them from performing basic life support. Animal models of prehospital cardiac arrest indicates that 24-h survival is essentially as good with chest compression-only CPR as with chest compressions and assisted ventilation. ⋯ As anticipated arterial blood gases were not as good, but hemodynamics produced were better with chest compression-only CPR (P < 0.05). Chest compression-only CPR, even with a totally occluded airway, is as good as standard CPR for successful outcome following 6.5 min of cardiac arrest. Such a strategy for the first minutes of cardiac arrest, particularly before professional help arrives, has several advantages including increased acceptability to the lay public.
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Comparative Study
Jaw lift--a simple and effective method to open the airway in children.
Assessment of breathing during resuscitation of children is important. Misjudgement due to failure to open the airway may lead to mouth-to-mouth ventilation in unconscious children who have retained spontaneous breathing efforts, and might lead to completely ineffective ventilation with gastric distension. The efficiency of the standard head tilt-chin lift manoeuvre (HT-CL) and the jaw lift manoeuvre (JL) for opening of the airway in children was investigated. ⋯ The standard HT-CL manoeuvre was insufficient in 12% of the children. JL was more effective than HT-CL in opening the airway in unconscious children who had retained attempts at spontaneous breathing. The JL manoeuvre may, therefore, be recommended in situations when the HT-CL manoeuvre is insufficient.
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Our purpose was to determine if core hypothermia influences physiological responses to norepinephrine (NE); and if rewarming reverses these effects. Animals were instrumented to measure mean arterial pressure (MAP) and cardiac output (CO). Core temperature was manipulated from 37.5 degrees C (normothermia), to 30 degrees C (hypothermia) and the back to 37.5 degrees C (rewarming) using an external arterial-venous femoral shunt. ⋯ The response to NE during hypothermia was a significant increase in MAP only at doses of 1 microg kg(-1) per min (P = 0.03) and 5 microg kg(-1) per min (P = 0.01). The response to NE after rewarming was a significant increase in MAP only at a dose of 5 microg kg(-1) per min (P = 0.03). This study shows that core hypothermia causes a change in physiological response to NE that rewarming does not reverse.
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Comparative Study
Improved haemodynamics with increased compression-decompression rates during ACD-CPR in pigs.
The haemodynamic effects of variations in the compression-decompression frequency, 60, 90 and 120 min(-1) during ACD-CPR, were tested in a randomized cross-over design during ventricular fibrillation (VF) in 12 anaesthetized pigs (17-22 kg) using an automatic hydraulic chest compression-decompression device. There were significant increases with increasing frequency for mean (+/- S. D.) carotid blood flow (17 +/- 5, 25 +/- 9 and 36 +/- 12 ml min(-1), transit time flow probe), cerebral blood flow (17 +/- 7, 30 +/- 17 and 40 +/- 13 ml min(-1) 100 g(-1), radionuclide microspheres) and mean aortic pressure (34 +/- 8, 37 +/- 10 and 43 +/- 7 mmHg), respectively. ⋯ Renal and hepatic blood flow also increased with increasing rate. No significant differences in the expired CO2 levels were observed. In conclusion increasing the compression-decompression frequency from 60 to 90 and 120 min(-1) improved the haemodynamics during ACD-CPR in a pig model with VF.