ORIGINAL CONTRIBUTION cardiac arrest, resuscitation
The Role of Bicarbonate and Fluid Loading in Improving Resuscitation From Prolonged Cardiac Arrest With Rapid Manual Chest Compression CPR Rapid manual chest compression (120 compressions/rain) CPR has been shown to improve hemodynamics and survival when compared with standard CPR (60 compressions/rain) in a canine model of prolonged cardiac arrest. The study showing improved survival with rapid manual CPR empirically included treatment with bicarbonate and initial fluid loading. To determine the role of bicarbonate and fluid loading in the success of rapid manual chest compression CPR, 31 mongrel dogs were studied. After instrumentation with micromanometer-tipped catheters to measure aortic and right atrial pressures, the animals were assigned sequentially to three treatment groups. Group A underwent rapid manual chest compressions at 120 compressions/rain, bicarbonate treatment, and initial fluid loading. Group B underwent rapid manual compressions at 120 compressions/min without bicarbonate or fluid loading. Group C underwent standard CPR at 80 compressions/rain with bicarbonate and fluid loading. After 30 minutes of ventricular fibrillation, defibrillation was attempted. Seven of 1i dogs in group A survived 24 hours. None of the animals in group B resuscitated or survived. Three of the ten dogs in group C survived 24 hours. Survival with rapid manual CPR without bicarbonate and initial fluid loading was significantly less than when these interventions were used (P < .01). To examine the separate contribution of bicarbonate and fluid therapy, two additional groups of animals were studied. Fourteen animals (group D) received rapid manual CPR with bicarbonate therapy, and 12 (group E) received rapid manual CPR with fluid loading only. Three of 14 in group D and two of 12 in group E survived 24 hours. This study confirms the benefit of using rapid manual chest compression CPR compared >eqth standard CPR. However, use of Mcarbonate and fluid loading is necessary to achieve improved outcome with rapid manual chest compression CPR. /Sanders AB, Kern KB, Fonken S, Otto CW, Ewy GA: The role of bicarbonate and fluid loading in improving resuscitation from prolonged cardiac arrest with rapid manual chest compression CPR. Ann Emerg Med January 1990;19:1-7.]
Arthur B Sanders, MD, FACEP* Kad B Kern, MDt Steve Fonken, MDt Charles W Otto, MD¢ Gordon A Ewy, MD~ Tucson, Arizona From the Section of Emergency Medicine, Department of Surgery,* Section of Cardiology, Department of Internal Medicine,t and Department of Anesthesia and Internal Medicine,* University of Arizona College of Medicine, Arizona Health Sciences Center; and Tucson VA Medical Center, Tucson. Received for publication March 13, 1989. Revision received July 24, 1989. Accepted for publication August 31, 1989. Presented at the University Association for Emergency Medicine Annual Meeting in Cincinnati, May 1988. This study was supported by grants from the American Heart Association, Arizona Affiliate, and The Flinn Foundation, Phoenix, Arizona. Address for reprints: Arthur B Sanders, MD, PACER Section of Emergency Medicine, Arizona Health Sciences Center, 1501 North Campbell Avenue, Tucson, Arizona 85724.
INTRODUCTION The o p t i m a l rate of cardiac compression for the resuscitation of patients in cardiac arrest is u n k n o w n . Studies in canine models of prolonged cardiac a r r e s t d e m o n s t r a t e d i m p r o v e d h e m o d y n a m i c s w h e n c o m p r e s s i o n rates of 120 c o m p r e s s i o n s / m i n were c o m p a r e d w i t h 60 c o m p r e s s i o n s / min. 1-4 A recent o u t c o m e study d e m o n s t r a t e d improved survival at the faster compression rate. 4 T h e protocol for the study included t r e a t m e n t with s o d i u m bicarbonate and initial fluid loading w i t h saline to a m e a n right a t r i a l pressure of 6 to 8 m m Hg. Both c o n t r o l and e x p e r i m e n t a l groups received b i c a r b o n a t e and fluid loading, i m p l y i n g that the beneficial effect from rapid m a n u a l CPR was due to the increased rate. The effect of bicarbonate and fluid a d m i n i s t r a t i o n on the success of rapid m a n u a l CPR has n o t been explored. T h e purpose of our study was to d e t e r m i n e w h e t h e r bicarbonate and fluid loading are necessary to improve resuscitation and 24-hour survival using r a p i d m a n u a l chest compression CPR in a canine model of prolonged cardiac arrest.
19:1 January 1990
Annals of Emergency Medicine
1/21
BICARBONATE AND FLUID LOADING Sanders et al
FIGURE 1. Bar graph of the comparison of the 24-hour survival in group A (rapid manual chest compression CPR with bicarbonate and fluids), group B (rapid manual chest compression CPR without bicarbonate or fluids), and group C dogs (standard manual CPR with bicarbonate and fluids). A significant difference in survival is demonstrated by X2 analysis (P < .05).
12
7/11 0/10
3/10
Group A
Group B
Group C
Rapid Manual CPR
Rapid Manual CPR
Standard CPR
® Bicarbonate (9 Fluids
(9 Bicarbonate
(9 Bicarbonate
(9 Fluids
@ Fluids
10 8 6 o9
4
FIGURE 2. Plot of the comparison of the mean +_ SD aortic systolic pressures in group A (rapid manual chest compression CPR with bicarbonate and fluids), group B (rapid manual chest compression CPR without bicarbonate and fluids), and group C dogs (standard manual CPR with bicarbonate and fluids). No significant differences were demonstrated among the three groups.
2 0
METHODS Experimental Preparation The protocol was approved by the U n i v e r s i t y of Arizona College of Medicine L a b o r a t o r y A n i m a l Research Committee. Mongrel dogs (20 to 30 kg) demonstrated to be free of h e a r t w o r m s were pretreated with morphine sulfate (2 mg/kg) and anesthetized with halothane (0.5% to 1%) titrated using the animal's corneal reflex. The animals were endotracheally intubated and ventilated with a volume ventilator set at 15 mL/kg at a rate of 12. Vascular sheaths were placed in a femoral artery and both femoral veins. High-fidelity micromanometer-tipped catheters (Millar PC-500) were zeroed, calibrated at 37 C, and inserted through the femoral artery and a vein into the aorta and right atrium using pressure waveform guidance. Fluoroscopic confirmation was used when necessary. A 4F bipolar pacing catheter was placed through a femoral venous sheath into the right ventricle using ECG guidance. Lead II of the ECG and aortic and right atrial pressures were monitored continuously. Data were acquired at one-minute intervals o n . a Gould four-channel recorder during the experimental protocol.
Experimental Protocol Thirty-one animals were assigned to one of three treatment groups in a r o t a t i n g (not r a n d o m ) s e q u e n c e . 22/2
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Group A underwent rapid manual chest compressions at 120 compressions/min with initial fluid loading and bicarbonate treatment. Group B underwent rapid manual compressions at 120 eompressions/min without bicarbonate treatment or fluid loading. Group C underwent standard CPR at 80 compressions/rain with bicarbonate treatment and initial fluid loading identical to group A. In an effort to duplicate the protocol of the previous studyl 4 groups A and C received initial fluid loading and bicarbonate therapy before and during the resuscitation. The fluidAnnals of Emergency Medicine
loading regimen consisted of an infusion of normal saline to achieve a mean right atrial pressure of 6 to 8 m m Hg before induction of ventricular fibrillation. The bicarbonate regimen consisted of 25 mEq Na bicarbonate administered just before the induction of ventricular fibrillation. During cardiac arrest and CPR, 20 mEq bicarbonate was administered at five minutes of ventricular fibrillation, and i0 mEq was administered at ten, 15, 20, and 25 minutes of ventricular fibrillation. In addition, 50 mEq Na bicarbonate was administered after the first defibrillation at19:1 January 1990
FIGURE 3. Plot of the comparison of the m e a n ± SD aortic diastolic pressures in group A (rapid manual chest compression CPR w i t h bicarbonate and fluids), group B (rapid m a n u a l chest compression CPR w i t h o u t bicarbonate and fluids), and group C dogs (standard manual CPR with bicarbonate and fluids). ~Group A was significantly different from group B at 15 m i n u t e s of cardiac arrest (P < .05).
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The Role of Bicarbonate and Fluid Loading in Improving Resuscitation From Prolonged Cardiac Arrest With Rapid Manual Chest Compression CPR Rapid manual chest compression (120 compressions/rain) CPR has been shown to improve hemodynamics and survival when compared with standard CPR (60 compressions/rain) in a canine model of prolonged cardiac arrest. The study showing improved survival with rapid manual CPR empirically included treatment with bicarbonate and initial fluid loading. To determine the role of bicarbonate and fluid loading in the success of rapid manual chest compression CPR, 31 mongrel dogs were studied. After instrumentation with micromanometer-tipped catheters to measure aortic and right atrial pressures, the animals were assigned sequentially to three treatment groups. Group A underwent rapid manual chest compressions at 120 compressions/rain, bicarbonate treatment, and initial fluid loading. Group B underwent rapid manual compressions at 120 compressions/min without bicarbonate or fluid loading. Group C underwent standard CPR at 80 compressions/rain with bicarbonate and fluid loading. After 30 minutes of ventricular fibrillation, defibrillation was attempted. Seven of 1i dogs in group A survived 24 hours. None of the animals in group B resuscitated or survived. Three of the ten dogs in group C survived 24 hours. Survival with rapid manual CPR without bicarbonate and initial fluid loading was significantly less than when these interventions were used (P < .01). To examine the separate contribution of bicarbonate and fluid therapy, two additional groups of animals were studied. Fourteen animals (group D) received rapid manual CPR with bicarbonate therapy, and 12 (group E) received rapid manual CPR with fluid loading only. Three of 14 in group D and two of 12 in group E survived 24 hours. This study confirms the benefit of using rapid manual chest compression CPR compared >eqth standard CPR. However, use of Mcarbonate and fluid loading is necessary to achieve improved outcome with rapid manual chest compression CPR. /Sanders AB, Kern KB, Fonken S, Otto CW, Ewy GA: The role of bicarbonate and fluid loading in improving resuscitation from prolonged cardiac arrest with rapid manual chest compression CPR. Ann Emerg Med January 1990;19:1-7.]
Arthur B Sanders, MD, FACEP* Kad B Kern, MDt Steve Fonken, MDt Charles W Otto, MD¢ Gordon A Ewy, MD~ Tucson, Arizona From the Section of Emergency Medicine, Department of Surgery,* Section of Cardiology, Department of Internal Medicine,t and Department of Anesthesia and Internal Medicine,* University of Arizona College of Medicine, Arizona Health Sciences Center; and Tucson VA Medical Center, Tucson. Received for publication March 13, 1989. Revision received July 24, 1989. Accepted for publication August 31, 1989. Presented at the University Association for Emergency Medicine Annual Meeting in Cincinnati, May 1988. This study was supported by grants from the American Heart Association, Arizona Affiliate, and The Flinn Foundation, Phoenix, Arizona. Address for reprints: Arthur B Sanders, MD, PACER Section of Emergency Medicine, Arizona Health Sciences Center, 1501 North Campbell Avenue, Tucson, Arizona 85724.
INTRODUCTION The o p t i m a l rate of cardiac compression for the resuscitation of patients in cardiac arrest is u n k n o w n . Studies in canine models of prolonged cardiac a r r e s t d e m o n s t r a t e d i m p r o v e d h e m o d y n a m i c s w h e n c o m p r e s s i o n rates of 120 c o m p r e s s i o n s / m i n were c o m p a r e d w i t h 60 c o m p r e s s i o n s / min. 1-4 A recent o u t c o m e study d e m o n s t r a t e d improved survival at the faster compression rate. 4 T h e protocol for the study included t r e a t m e n t with s o d i u m bicarbonate and initial fluid loading w i t h saline to a m e a n right a t r i a l pressure of 6 to 8 m m Hg. Both c o n t r o l and e x p e r i m e n t a l groups received b i c a r b o n a t e and fluid loading, i m p l y i n g that the beneficial effect from rapid m a n u a l CPR was due to the increased rate. The effect of bicarbonate and fluid a d m i n i s t r a t i o n on the success of rapid m a n u a l CPR has n o t been explored. T h e purpose of our study was to d e t e r m i n e w h e t h e r bicarbonate and fluid loading are necessary to improve resuscitation and 24-hour survival using r a p i d m a n u a l chest compression CPR in a canine model of prolonged cardiac arrest.
19:1 January 1990
Annals of Emergency Medicine
1/21
BICARBONATE AND FLUID LOADING Sanders et al
FIGURE 1. Bar graph of the comparison of the 24-hour survival in group A (rapid manual chest compression CPR with bicarbonate and fluids), group B (rapid manual chest compression CPR without bicarbonate or fluids), and group C dogs (standard manual CPR with bicarbonate and fluids). A significant difference in survival is demonstrated by X2 analysis (P < .05).
12
7/11 0/10
3/10
Group A
Group B
Group C
Rapid Manual CPR
Rapid Manual CPR
Standard CPR
® Bicarbonate (9 Fluids
(9 Bicarbonate
(9 Bicarbonate
(9 Fluids
@ Fluids
10 8 6 o9
4
FIGURE 2. Plot of the comparison of the mean +_ SD aortic systolic pressures in group A (rapid manual chest compression CPR with bicarbonate and fluids), group B (rapid manual chest compression CPR without bicarbonate and fluids), and group C dogs (standard manual CPR with bicarbonate and fluids). No significant differences were demonstrated among the three groups.
2 0
METHODS Experimental Preparation The protocol was approved by the U n i v e r s i t y of Arizona College of Medicine L a b o r a t o r y A n i m a l Research Committee. Mongrel dogs (20 to 30 kg) demonstrated to be free of h e a r t w o r m s were pretreated with morphine sulfate (2 mg/kg) and anesthetized with halothane (0.5% to 1%) titrated using the animal's corneal reflex. The animals were endotracheally intubated and ventilated with a volume ventilator set at 15 mL/kg at a rate of 12. Vascular sheaths were placed in a femoral artery and both femoral veins. High-fidelity micromanometer-tipped catheters (Millar PC-500) were zeroed, calibrated at 37 C, and inserted through the femoral artery and a vein into the aorta and right atrium using pressure waveform guidance. Fluoroscopic confirmation was used when necessary. A 4F bipolar pacing catheter was placed through a femoral venous sheath into the right ventricle using ECG guidance. Lead II of the ECG and aortic and right atrial pressures were monitored continuously. Data were acquired at one-minute intervals o n . a Gould four-channel recorder during the experimental protocol.
Experimental Protocol Thirty-one animals were assigned to one of three treatment groups in a r o t a t i n g (not r a n d o m ) s e q u e n c e . 22/2
80 70 E
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20
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1
5
10
15
20
25
29
Time (min)
Group A underwent rapid manual chest compressions at 120 compressions/min with initial fluid loading and bicarbonate treatment. Group B underwent rapid manual compressions at 120 eompressions/min without bicarbonate treatment or fluid loading. Group C underwent standard CPR at 80 compressions/rain with bicarbonate treatment and initial fluid loading identical to group A. In an effort to duplicate the protocol of the previous studyl 4 groups A and C received initial fluid loading and bicarbonate therapy before and during the resuscitation. The fluidAnnals of Emergency Medicine
loading regimen consisted of an infusion of normal saline to achieve a mean right atrial pressure of 6 to 8 m m Hg before induction of ventricular fibrillation. The bicarbonate regimen consisted of 25 mEq Na bicarbonate administered just before the induction of ventricular fibrillation. During cardiac arrest and CPR, 20 mEq bicarbonate was administered at five minutes of ventricular fibrillation, and i0 mEq was administered at ten, 15, 20, and 25 minutes of ventricular fibrillation. In addition, 50 mEq Na bicarbonate was administered after the first defibrillation at19:1 January 1990
FIGURE 3. Plot of the comparison of the m e a n ± SD aortic diastolic pressures in group A (rapid manual chest compression CPR w i t h bicarbonate and fluids), group B (rapid m a n u a l chest compression CPR w i t h o u t bicarbonate and fluids), and group C dogs (standard manual CPR with bicarbonate and fluids). ~Group A was significantly different from group B at 15 m i n u t e s of cardiac arrest (P < .05).
40 E Q) 03 03
30
0... .o 20 .9_,o 03
¢3 0
10
= •
. . . .
• ........
