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Volume shifts significantly impact chest compression generated blood flow
Poster Presentations / Resuscitation 83 (2012) e24–e123
AP081 The evaluation of physiological responses during the performance of external chest compressions in simulated hypo and microgravity Thais Russomano 1,2,3,∗ , Rafael Baptista 1,2,3 , Nicholas Corrêa 1,2,3 , Mariana Dias 1,2,3 1 Pontifícia Universidade Católica of Rio Grande do Sul, Porto Alegre, RS, Brazil 2 Microgravity Center, Porto Alegre, RS, Brazil 3 Physical Education and Sports Science Faculty, Porto Alegre, RS, Brazil
The aim of this study was to evaluate physiological responses during cardiopulmonary resuscitation (CPR) in hypogravity (hypoG) and microgravity (microG) simulations, and to compare these with 1G (Earth’s gravity). A CPR training manikin was used with an indicator for depth and frequency of compressions, along with surface electromyography (EMG), a mobile heart rate (HR) monitor and the Borg Scale. A body suspension device was used to reduce body weight during CPR in hypoG and microG simulations. Thirty male volunteers (21.97 ± 2.94 years) performed 3 sets of 30 chest compressions, with a 6-s interval between sets to allow for ventilation time, for each of the 3 different gravity scenarios. Everyone achieved a compression rate and depth within the expected values. The data for maximum HR, variation in HR and perceived exertion were higher for performances in microG (146.50 ± 26.56 bpm; 73.30 ± 24.53 bpm; 16.07 ± 2.29 points) and hypoG (109.40 ± 19.62 bpm; 36.20 ± 17.19 bpm; 11.60 ± 2.59 points) than observed at 1G (101.37 ± 20.47 bpm; 28.17 ± 15.36 bpm; 9.57 ± 2.19 points). The EMG showed greater activation of the rectus abdominis muscle (0.07 ± 0.18 uv) at 1G when compared to the pectoralis major (0.06 ± 0.04 uv) and triceps brachii (0.04 ± 0.03 uv) muscles. In hypoG, the activation of the pectoralis major muscle was greater (0.16 ± 0.40 uv) than that of the triceps brachii (0.11 ± 0.27 uv). No significant difference in EMG was seen between 1G and hypoG. A lower activity was observed for the triceps brachii (0.09 ± 0.07 uv) in microG in comparison to the pectoralis major (0.16 ± 0.11 uv) and rectus abdominis (0.35 ± 0.68 uv) muscles. However, all of the muscles being studied showed an increased activity during microG simulation. The results of this study suggest that the rescuer expends more effort and requires increased muscle recruitment to maintain an adequate performance of CPR in microG.
Further reading
e55
Introduction: The existence of a blood volume shift during resuscitation has been a hypothetical explanation of the observed reduction in chest compression (CC) efficacy as a function of time. However, central blood flows, and therefore volumes, have not been thoroughly investigated during prolonged CPR. Methods: CPR hemodynamics in nine domestic swine (∼30 kg) were studied using standard physiological monitoring. Flow and pressure sensors were placed on the abdominal aorta (AA) and the inferior vena cava (IVC) slightly inferior to the kidneys. Ventricular fibrillation (VF) was electrically induced. Mechanical CC were started after ten minutes of untreated VF and continued for 54 min. Results: Hemodynamic data indicate that study animals separated into two groups depending on the direction of the final net IVC flow. At the end of resuscitation, IVC and AA flows were significantly different between animals with net forward IVC flow (IVCpos) and net negative IVC flow (IVCneg). Surprisingly, IVCneg animals had higher forward AA flows. As a result, IVCneg animals were adding blood volume to the tissue below the flow probes whereas IVCpos animals were removing blood volume from the tissue below the flow probes at the end of resuscitation. Conclusions: Both the IVCneg and the IVCpos groups experienced significant volume shifts during the resuscitation. However, the volume shifts appear to be in opposite directions. The volume shifts between these reservoirs have a profound impact on the distribution of CC generated blood flow. These observations require further investigation into the hemodynamics of volume shifts during resuscitation. IVC flow [ml/min]
IVCneg (n = 4) IVCpos (n = 5) p-Value
Abdominal aorta flow [ml/min]
Initial
End
Initial
End
24 ± 33.4 67.8 ± 12.8 0.22
−51.14 ± 22.4 49.9 ± 13.9 0.005
68.1 ± 18.9 76 ± 88 0.87
8.0 ± 2.0 −2.1 ± 1.8 0.006
http://dx.doi.org/10.1016/j.resuscitation.2012.08.141
Defibrillation AP083 Caregiver safety in defibrillation: Where does the energy go? Ellen vd Loo 1,3,4,5 , Igor Paulussen 2,3,4,5 , Jelle Cloin 1,3,4,5 , Paul Aelen 2,3,4,5 , Paul van Berkom 1,3,4,5,∗ , Gerrit Jan 1,3,4,5 Noordergraaf 1
St. Elisabeth Hospital, Tilburg, The Netherlands Philips Research, Eindhoven, The Netherlands 3 Zoll, Elst, The Netherlands 4 Physio Control, Kerkrade, The Netherlands 5 Medtronics, Heerlen, The Netherlands 2
1. Kordi M, Cardoso RB, Russomano T. A preliminary comparison between methods of performing external chest compressions during microgravity simulation. Aviat Space Environ Med 2011;82:1161–3. 2. Rehnberg L, Russomano T, Falcao F, Campos F, Evetts SN. Evaluation of a novel basic life support method in simulated microgravity. Aviat Space Environ Med 2011;82:104–10. 3. Evetts SN, Evetts LM, Russomano T, Castro JC, Ernsting J. Basic life support in microgravity: evaluation of a novel method during parabolic flight. Aviat Space Environ Med 2005;76:506–10.
http://dx.doi.org/10.1016/j.resuscitation.2012.08.140 AP082 Volume shifts significantly impact chest compression generated blood flow Joshua Lampe 1,∗ , Josiah Garcia 1 , Tai Yin 1 , George Bratinov 1 , Christopher Kaufman 2 , Lance Becker 1 1 2
University of Pennsylvania, Philadelphia, PA, USA ZOLL Medical Corporation, Chelmsford, MA, USA
Purpose of the study: A major cardiopulmonary resuscitation (CPR) priority is limiting interruptions to chest compressions. Early defibrillator charging, quick EKG analysis, a shock, and immediate resumption of compressions has been advocated. Defibrillation pads are now standard practice. This combination may increase risks to caregivers, but data is limited.1–3 We developed a model to quantify electrical dispersion in humans, in combination with a pilot study of the potential energy flow to caregivers under standard clinical conditions to test the hypotheses that touching the patient during defibrillation is dangerous.1,3 Materials and methods: In the model a patient was simulated with defibrillator pads (apex – subclavicular/right sternal) and 20 measurement points (mid sternal, thoracic, shoulders, chin, mandible, arms, abdominal, upper legs) and mathematical descrip-
AP081 The evaluation of physiological responses during the performance of external chest compressions in simulated hypo and microgravity Thais Russomano 1,2,3,∗ , Rafael Baptista 1,2,3 , Nicholas Corrêa 1,2,3 , Mariana Dias 1,2,3 1 Pontifícia Universidade Católica of Rio Grande do Sul, Porto Alegre, RS, Brazil 2 Microgravity Center, Porto Alegre, RS, Brazil 3 Physical Education and Sports Science Faculty, Porto Alegre, RS, Brazil
The aim of this study was to evaluate physiological responses during cardiopulmonary resuscitation (CPR) in hypogravity (hypoG) and microgravity (microG) simulations, and to compare these with 1G (Earth’s gravity). A CPR training manikin was used with an indicator for depth and frequency of compressions, along with surface electromyography (EMG), a mobile heart rate (HR) monitor and the Borg Scale. A body suspension device was used to reduce body weight during CPR in hypoG and microG simulations. Thirty male volunteers (21.97 ± 2.94 years) performed 3 sets of 30 chest compressions, with a 6-s interval between sets to allow for ventilation time, for each of the 3 different gravity scenarios. Everyone achieved a compression rate and depth within the expected values. The data for maximum HR, variation in HR and perceived exertion were higher for performances in microG (146.50 ± 26.56 bpm; 73.30 ± 24.53 bpm; 16.07 ± 2.29 points) and hypoG (109.40 ± 19.62 bpm; 36.20 ± 17.19 bpm; 11.60 ± 2.59 points) than observed at 1G (101.37 ± 20.47 bpm; 28.17 ± 15.36 bpm; 9.57 ± 2.19 points). The EMG showed greater activation of the rectus abdominis muscle (0.07 ± 0.18 uv) at 1G when compared to the pectoralis major (0.06 ± 0.04 uv) and triceps brachii (0.04 ± 0.03 uv) muscles. In hypoG, the activation of the pectoralis major muscle was greater (0.16 ± 0.40 uv) than that of the triceps brachii (0.11 ± 0.27 uv). No significant difference in EMG was seen between 1G and hypoG. A lower activity was observed for the triceps brachii (0.09 ± 0.07 uv) in microG in comparison to the pectoralis major (0.16 ± 0.11 uv) and rectus abdominis (0.35 ± 0.68 uv) muscles. However, all of the muscles being studied showed an increased activity during microG simulation. The results of this study suggest that the rescuer expends more effort and requires increased muscle recruitment to maintain an adequate performance of CPR in microG.
Further reading
e55
Introduction: The existence of a blood volume shift during resuscitation has been a hypothetical explanation of the observed reduction in chest compression (CC) efficacy as a function of time. However, central blood flows, and therefore volumes, have not been thoroughly investigated during prolonged CPR. Methods: CPR hemodynamics in nine domestic swine (∼30 kg) were studied using standard physiological monitoring. Flow and pressure sensors were placed on the abdominal aorta (AA) and the inferior vena cava (IVC) slightly inferior to the kidneys. Ventricular fibrillation (VF) was electrically induced. Mechanical CC were started after ten minutes of untreated VF and continued for 54 min. Results: Hemodynamic data indicate that study animals separated into two groups depending on the direction of the final net IVC flow. At the end of resuscitation, IVC and AA flows were significantly different between animals with net forward IVC flow (IVCpos) and net negative IVC flow (IVCneg). Surprisingly, IVCneg animals had higher forward AA flows. As a result, IVCneg animals were adding blood volume to the tissue below the flow probes whereas IVCpos animals were removing blood volume from the tissue below the flow probes at the end of resuscitation. Conclusions: Both the IVCneg and the IVCpos groups experienced significant volume shifts during the resuscitation. However, the volume shifts appear to be in opposite directions. The volume shifts between these reservoirs have a profound impact on the distribution of CC generated blood flow. These observations require further investigation into the hemodynamics of volume shifts during resuscitation. IVC flow [ml/min]
IVCneg (n = 4) IVCpos (n = 5) p-Value
Abdominal aorta flow [ml/min]
Initial
End
Initial
End
24 ± 33.4 67.8 ± 12.8 0.22
−51.14 ± 22.4 49.9 ± 13.9 0.005
68.1 ± 18.9 76 ± 88 0.87
8.0 ± 2.0 −2.1 ± 1.8 0.006
http://dx.doi.org/10.1016/j.resuscitation.2012.08.141
Defibrillation AP083 Caregiver safety in defibrillation: Where does the energy go? Ellen vd Loo 1,3,4,5 , Igor Paulussen 2,3,4,5 , Jelle Cloin 1,3,4,5 , Paul Aelen 2,3,4,5 , Paul van Berkom 1,3,4,5,∗ , Gerrit Jan 1,3,4,5 Noordergraaf 1
St. Elisabeth Hospital, Tilburg, The Netherlands Philips Research, Eindhoven, The Netherlands 3 Zoll, Elst, The Netherlands 4 Physio Control, Kerkrade, The Netherlands 5 Medtronics, Heerlen, The Netherlands 2
1. Kordi M, Cardoso RB, Russomano T. A preliminary comparison between methods of performing external chest compressions during microgravity simulation. Aviat Space Environ Med 2011;82:1161–3. 2. Rehnberg L, Russomano T, Falcao F, Campos F, Evetts SN. Evaluation of a novel basic life support method in simulated microgravity. Aviat Space Environ Med 2011;82:104–10. 3. Evetts SN, Evetts LM, Russomano T, Castro JC, Ernsting J. Basic life support in microgravity: evaluation of a novel method during parabolic flight. Aviat Space Environ Med 2005;76:506–10.
http://dx.doi.org/10.1016/j.resuscitation.2012.08.140 AP082 Volume shifts significantly impact chest compression generated blood flow Joshua Lampe 1,∗ , Josiah Garcia 1 , Tai Yin 1 , George Bratinov 1 , Christopher Kaufman 2 , Lance Becker 1 1 2
University of Pennsylvania, Philadelphia, PA, USA ZOLL Medical Corporation, Chelmsford, MA, USA
Purpose of the study: A major cardiopulmonary resuscitation (CPR) priority is limiting interruptions to chest compressions. Early defibrillator charging, quick EKG analysis, a shock, and immediate resumption of compressions has been advocated. Defibrillation pads are now standard practice. This combination may increase risks to caregivers, but data is limited.1–3 We developed a model to quantify electrical dispersion in humans, in combination with a pilot study of the potential energy flow to caregivers under standard clinical conditions to test the hypotheses that touching the patient during defibrillation is dangerous.1,3 Materials and methods: In the model a patient was simulated with defibrillator pads (apex – subclavicular/right sternal) and 20 measurement points (mid sternal, thoracic, shoulders, chin, mandible, arms, abdominal, upper legs) and mathematical descrip-