After a femoral incision, a polyethylene catheter was
introduced into the right femoral artery and advanced to the
right ascending aorta for pressure recordings and arterial
blood sampling. A Swan-Ganz catheter (Baxter Healthcare)
was inserted in the right femoral vein, and the tip was advanced
to the pulmonary artery for wedge pressure recordings
and mixed venous blood sampling. ECG electrodes
were placed to allow recording of lead II. After a 20-minute
stabilization period, the right external jugular vein was isolated
and a pacing wire was advanced into the heart; an
alternating current was applied for 3 to 5 seconds to induce
fibrillation. Fibrillation was indicated by the absence of
pulse and an abrupt fall in arterial pressure and confirmed
by the ECG tracing. Chest compression was begun 30 seconds
after the beginning of fibrillation, using the Thumper
to ensure reproducibility. After 20 minutes, defibrillationwas attempted by administration of 120 and 300 J (three
times each) from the 43130A Defibrillator (Hewlett-Packard).
If defibrillation was successful (return of spontaneous circulation),
the pigs were monitored for an additional 20 minutes
for recurrent arrhythmias. Blood samples were taken
at 15-minute intervals during the control period; at 1, 3, 5,
and 20 minutes of resuscitation; and 20 minutes after successful
defibrillation. The pigs were killed by an overdose
of pentobarbital sodium and potassium chloride (Somlethol)
(1 mL/10 lb body weight) and discontinuation of CPR at
the end of the experiment.
After a femoral incision, a polyethylene catheter wasintroduced into the right femoral artery and advanced to theright ascending aorta for pressure recordings and arterialblood sampling. A Swan-Ganz catheter (Baxter Healthcare)was inserted in the right femoral vein, and the tip was advancedto the pulmonary artery for wedge pressure recordingsand mixed venous blood sampling. ECG electrodeswere placed to allow recording of lead II. After a 20-minutestabilization period, the right external jugular vein was isolatedand a pacing wire was advanced into the heart; analternating current was applied for 3 to 5 seconds to inducefibrillation. Fibrillation was indicated by the absence ofpulse and an abrupt fall in arterial pressure and confirmedby the ECG tracing. Chest compression was begun 30 secondsafter the beginning of fibrillation, using the Thumperto ensure reproducibility. After 20 minutes, defibrillationwas attempted by administration of 120 and 300 J (threetimes each) from the 43130A Defibrillator (Hewlett-Packard).If defibrillation was successful (return of spontaneous circulation),the pigs were monitored for an additional 20 minutesfor recurrent arrhythmias. Blood samples were takenat 15-minute intervals during the control period; at 1, 3, 5,and 20 minutes of resuscitation; and 20 minutes after successfuldefibrillation. The pigs were killed by an overdoseof pentobarbital sodium and potassium chloride (Somlethol)(1 mL/10 lb body weight) and discontinuation of CPR atthe end of the experiment.
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