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Serum lidocaine levels during CPR in humans after endotracheal and intravenous administration
ABSTRACTS
tracheal tube or intravenously in doses sufficient to average 5 mcg/kg/min until they arrived in the emergency department. After arrival, epinephrine infusions were started to accomplish this same dose. Central arterial and central venous pressure catheters were placed through the femoral artery and femoral vein, respectively, and advanced into the chest. By use of high-compression force CPR and a modified Michigan Instruments Thumper@, which is computerized, CPR was performed in the following manner. There were five compression-relaxation cycles followed by a diastolic ventilation. The compression-relaxation relationship was equal, i.e. ~ each was 50% of the cycle. The rate of compression was 60 per minute. The ventilatory rate was 12 per minute. Compression force was high, averaging 120 pounds. Simultaneously recorded arterial and venous pressure curves were analyzed. Pressures reported were obtained from measurements of these curves. Digital readouts were not used. The DA-DCVP was derived by subtracting the mean of the diastolic central venous pressure from the mean of simultaneously recorded central diastolic arterial pressure. All victims were late in the resuscitative process, i.e., at least 30 minutes post cardiac arrest at the time’pressure recording was begun. In the three patients studied. none of whom survived, the DA-DCVP was less in each instance than 12 mm Hg. Studies have indicated that zero flow pressure in the nonfibrillating victim is 11-15 mm Hg. In the fibrillating victim it is probably higher. Thus, it appears that in those victims who were studied the heart was not being perfused even with the use of moderately high doses of epinephrine, and that during the resuscitative attempt myocardial necrosis was ongoing, precluding the possibility of heart resuscitation. It could be that if pressure measurements could have been started earlier in the resuscitative phase the DA-DCVP would have been greater. Serum Lidocaine Levels during CPR in Humans after Endotracheal and Intravenous Administration. John L. McDonald. Santa Rosa Memorial Hospital, Santa Rosa, CA 95402. Serum lidocaine levels during CPR in human beings was determined when the chemical was given only endotracheally, only intravenously, and by a combination of endotracheal and intravenous administration. Lidocaine administration was begun in the prehospital care phase of treatment. Blood from which to determine the lidocaine levels was drawn subsequent to arrival of the victim in the emergency department. The results from 18 cases indicate that it is possible to develop therapeutic levels of lidocaine by endotracheal administration alone, by a combination of endotracheal and intravenous administration, and, as expected, by intravenous administration alone during CPR. Tentative conclusions are that the time to obtain therapeutic levels of lidocaine is longer with endotracheal than with intravenous administration but that therapeutic levels, once reached, persist longer with endotracheal than with intravenous administration. The tentative recommendation for dosage when endotracheal administration alone is used is three mg/ kg. It has not been determined whether a higher initial dose would produce a therapeutic level more quickly, although it seems reasonable to assume it would. Endotracheal admin-
FROM PURDUE CONFERENCE
ON CPR
istration of lidocaine in the presence of aspiration andior pulmonary edema may be unreliable in producing the desired therapeutic effect. It is difficult to interpret these results, because the time at which the blood was drawn from the time of the administration of the individual dose, or combination of doses, varied considerably. As a consequence, a distribution curve is being developed for serium lidocaine levels in the cardiac arrest model by means of determinations in selected patients every 10 minutes during CPR. From this distribution curve it may be possible to determine what the levels of lidocaine were or predict what they will be when only one determination is made during the resuscitation process, and thus derive considerably more value from this study, which will be extended to 36 cases. Other factors being studied for their effect on ultimate endotracheal absorption of lidocaine are the method of installation of the chemical down the ET tube, the influence of concomitant endotracheal administration of epinephrine, and a history of chronic obstructive pulmonary disease. External Cardiac Pacing. Carin H. Olson. State University of New York Upstate Medical Center, Syracuse, NY 13210. Cardiac pacing has been used successfully in patients with asystole or bradycardia compromising hemodynamics, when it is applied soon after the onset of the event. Because of the technical ease, speed of application, and minimal risks, an external cardiac pacemaker was used as part of initial resuscitative efforts. The technique was applied to patients arriving in the emergency department with nontraumatic arrest, asystole, agonal rhythm, pulseless idioventricular rhythm, or bradycardia with hemodynamic compromise. A pulse was successfully generated in only one of 12 patients. That patient was in complete AV dissociation. Other patients had the pacemaker applied after cardiopulmonary arrest. The pacemaker was applied within l-13 minutes (mean. 7 minutes) of the patient’s arrival in the emergency department. However, because of the long time before arrival, the interval between arrest and application of the pacemaker was 27-90 minutes (mean, 59 minutes). The nonresponding patients were in asystole or pulseless idioventricular rhythm when the pacemaker was applied. It was concluded that external cardiac pacing is useful for treatment of bradyarrhythmias. It may also be useful in the first few minutes after development of asystole, pulseless idioventricular rhythm, or agonal rhythem, but it is of no benefit if applied long after the event. The Relationship of the Cardiac Ventricles of Infants and Children to the Sternum as It Relates to External Cardiac Massage. James P. Orlowski, Margaret G. Zelch. The Cleveland Clinic Foundation, Cleveland, OH 44106. The Standards for Cardiopulmonary Resuscitation of the American Heart Association (AHA) and the National Academy of Sciences state that the cardiac ventricles of infants and small children lie higher in the chest than do those of older children and adults. Those standards recommend that when external cardiac compression (ECC) is performed on infants or young children the external pressure should be 355
tracheal tube or intravenously in doses sufficient to average 5 mcg/kg/min until they arrived in the emergency department. After arrival, epinephrine infusions were started to accomplish this same dose. Central arterial and central venous pressure catheters were placed through the femoral artery and femoral vein, respectively, and advanced into the chest. By use of high-compression force CPR and a modified Michigan Instruments Thumper@, which is computerized, CPR was performed in the following manner. There were five compression-relaxation cycles followed by a diastolic ventilation. The compression-relaxation relationship was equal, i.e. ~ each was 50% of the cycle. The rate of compression was 60 per minute. The ventilatory rate was 12 per minute. Compression force was high, averaging 120 pounds. Simultaneously recorded arterial and venous pressure curves were analyzed. Pressures reported were obtained from measurements of these curves. Digital readouts were not used. The DA-DCVP was derived by subtracting the mean of the diastolic central venous pressure from the mean of simultaneously recorded central diastolic arterial pressure. All victims were late in the resuscitative process, i.e., at least 30 minutes post cardiac arrest at the time’pressure recording was begun. In the three patients studied. none of whom survived, the DA-DCVP was less in each instance than 12 mm Hg. Studies have indicated that zero flow pressure in the nonfibrillating victim is 11-15 mm Hg. In the fibrillating victim it is probably higher. Thus, it appears that in those victims who were studied the heart was not being perfused even with the use of moderately high doses of epinephrine, and that during the resuscitative attempt myocardial necrosis was ongoing, precluding the possibility of heart resuscitation. It could be that if pressure measurements could have been started earlier in the resuscitative phase the DA-DCVP would have been greater. Serum Lidocaine Levels during CPR in Humans after Endotracheal and Intravenous Administration. John L. McDonald. Santa Rosa Memorial Hospital, Santa Rosa, CA 95402. Serum lidocaine levels during CPR in human beings was determined when the chemical was given only endotracheally, only intravenously, and by a combination of endotracheal and intravenous administration. Lidocaine administration was begun in the prehospital care phase of treatment. Blood from which to determine the lidocaine levels was drawn subsequent to arrival of the victim in the emergency department. The results from 18 cases indicate that it is possible to develop therapeutic levels of lidocaine by endotracheal administration alone, by a combination of endotracheal and intravenous administration, and, as expected, by intravenous administration alone during CPR. Tentative conclusions are that the time to obtain therapeutic levels of lidocaine is longer with endotracheal than with intravenous administration but that therapeutic levels, once reached, persist longer with endotracheal than with intravenous administration. The tentative recommendation for dosage when endotracheal administration alone is used is three mg/ kg. It has not been determined whether a higher initial dose would produce a therapeutic level more quickly, although it seems reasonable to assume it would. Endotracheal admin-
FROM PURDUE CONFERENCE
ON CPR
istration of lidocaine in the presence of aspiration andior pulmonary edema may be unreliable in producing the desired therapeutic effect. It is difficult to interpret these results, because the time at which the blood was drawn from the time of the administration of the individual dose, or combination of doses, varied considerably. As a consequence, a distribution curve is being developed for serium lidocaine levels in the cardiac arrest model by means of determinations in selected patients every 10 minutes during CPR. From this distribution curve it may be possible to determine what the levels of lidocaine were or predict what they will be when only one determination is made during the resuscitation process, and thus derive considerably more value from this study, which will be extended to 36 cases. Other factors being studied for their effect on ultimate endotracheal absorption of lidocaine are the method of installation of the chemical down the ET tube, the influence of concomitant endotracheal administration of epinephrine, and a history of chronic obstructive pulmonary disease. External Cardiac Pacing. Carin H. Olson. State University of New York Upstate Medical Center, Syracuse, NY 13210. Cardiac pacing has been used successfully in patients with asystole or bradycardia compromising hemodynamics, when it is applied soon after the onset of the event. Because of the technical ease, speed of application, and minimal risks, an external cardiac pacemaker was used as part of initial resuscitative efforts. The technique was applied to patients arriving in the emergency department with nontraumatic arrest, asystole, agonal rhythm, pulseless idioventricular rhythm, or bradycardia with hemodynamic compromise. A pulse was successfully generated in only one of 12 patients. That patient was in complete AV dissociation. Other patients had the pacemaker applied after cardiopulmonary arrest. The pacemaker was applied within l-13 minutes (mean. 7 minutes) of the patient’s arrival in the emergency department. However, because of the long time before arrival, the interval between arrest and application of the pacemaker was 27-90 minutes (mean, 59 minutes). The nonresponding patients were in asystole or pulseless idioventricular rhythm when the pacemaker was applied. It was concluded that external cardiac pacing is useful for treatment of bradyarrhythmias. It may also be useful in the first few minutes after development of asystole, pulseless idioventricular rhythm, or agonal rhythem, but it is of no benefit if applied long after the event. The Relationship of the Cardiac Ventricles of Infants and Children to the Sternum as It Relates to External Cardiac Massage. James P. Orlowski, Margaret G. Zelch. The Cleveland Clinic Foundation, Cleveland, OH 44106. The Standards for Cardiopulmonary Resuscitation of the American Heart Association (AHA) and the National Academy of Sciences state that the cardiac ventricles of infants and small children lie higher in the chest than do those of older children and adults. Those standards recommend that when external cardiac compression (ECC) is performed on infants or young children the external pressure should be 355