Resuscitation
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Comparative Study
Defibrillation threshold and cardiac responses using an external biphasic defibrillator with pediatric and adult adhesive patches in pediatric-sized piglets.
Before recommendations for using an automatic external defibrillator on pediatric patients can be made, a protocol for the energy of a biphasic waveform energy dosing needs to be determined that will allow ventricular defibrillation of 8 year olds while causing only a minimal amount of cardiac damage to infants. Pediatric- and adult-sized electrode patches were alternately applied to 10 isoflurane-anesthetized piglets weighing 3.8-20.1 kg to approximate the body weights of newborns to children < 8 years old. The defibrillation threshold (DFT) was determined for biphasic truncated exponential waveform shocks. ⋯ The same amount of energy delivered with a biphasic external defibrillator successfully defibrillated VF whether adult or pediatric patches were used. Cardiac rhythm and hemodynamic variables were unaltered at 60 s after shocks delivered at energies of up to 360 J. These data suggest that there is a substantial safety margin above a DFT strength shock for this biphasic waveform in piglets.
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Case Reports
Transient Brugada-type electrocardiographic abnormalities in renal failure reversed by dialysis.
The Brugada syndrome (BRS) is a hereditary cardiac condition (characteristically with a gene mutation affecting sodium channel function) identified by an elevated terminal portion of the QRS complex (prominent J wave) followed by a descending ST-segment elevation ending in a negative T wave in the right precordial leads, and malignant tachyarrhythmias in patients without demonstrable structural heart disease. We report a patient with a previous history of epilepsy treated with psychotropic drugs (with a sodium channel blocking effect) and chronic renal failure on haemodialysis who developed hyperkalaemia (6.6 mmol/l) and ECG findings resembling BRS. ⋯ Subsequently, a flecainide test did not reproduce ST-segment elevation. We conclude that hyperkalaemia associated with cardiac membrane active drugs may cause ECG changes mimicking the Brugada syndrome.
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Comparative Study
Resuscitation of hemorrhagic shock attenuates intrapulmonary nitric oxide formation.
Hemorrhagic shock has been shown to upregulate intrapulmonary inducible nitric oxide (NO) synthase (iNOS) expression. Increased intrapulmonary iNOS expression is reflected by increases in concentrations of NO in the airways. The purpose of this study was to examine the effects of resuscitation on this induction of intrapulmonary NO formation caused by hemorrhage. ⋯ Resuscitation attenuated the hemorrhage-induced upregulation of exhaled NO, iNOS protein and iNOS mRNA. This data suggests that resuscitation attenuates the hemorrhagic shock-induced formation of intrapulmonary NO by downregulating iNOS transcription. We believe that exhaled NO concentrations provide a useful, non-invasive method of monitoring the intrapulmonary inflammatory sequelae of hemorrhagic shock.
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The treatment of massive pulmonary embolus remains controversial. We describe the first report of the successful use of the thrombolytic agent, tenecteplase, in treating a hypotensive elderly patient with a saddle embolus. A brief review of the current literature concerning thrombolysis for massive pulmonary embolus is given.
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Comparative Study
Effect of rescuer fatigue on performance of continuous external chest compressions over 3 min.
Guidelines for the performance of cardiopulmonary resuscitation (CPR) have been revised recently and now advocate that chest compressions are performed without interruption for 3 min in patients during asystole and pulseless electrical activity. The aim of the present study was to determine if rescuer fatigue occurs during 3 min of chest compressions and if so, the effects on the rate and quality of compressions. Forty subjects competent in basic life support (BLS) were studied. ⋯ Seven subjects (five female, two male) were unable to complete the second 3-min period because of exhaustion. We conclude that rescuer fatigue adversely affects the quality of chest compressions when performed without interruption over a 3-min period and that this effect may be greater in females due to their smaller stature. Consideration should be given to rotating the rescuer performing chest compressions after 1 min intervals.