心跳停止之人的倖存機會，會隨著及早施行好品質的心肺復甦術(CPR)而增加。因此，心肺復甦術的操作品質與操作效能是一個重要的議題。胸外按壓是心肺復甦術中保持身體血液循環的一個主要的步驟。這是一個重複且費力的動作，容易使援救者產生疲勞和骨骼肌肉系統的傷害。正確的人體力學對胸腔按壓是必要的，它可以減少援救者產生疲勞，防止傷害援救者和被救者，並且保持心肺復甦術的效率。
生物力學的分析可以了解操作機轉與操作表現的相關性，並且提供改進的策略。但是至目前為止並沒有研究使用動作分析系統來量化及分析胸腔按壓的生物力學機轉。本研究的目的是︰1)使用動作分析方法建立一個分析專業救援者執行胸腔按壓的動作之運動的生物力學模式；2)評估不同的操作高度對胸腔按壓在運動學上的影響；3)評估不同的操作高度對胸腔按壓在腰椎負荷的影響；4)評估不同心肺復甦術之壓胸與通氣比率的對胸腔按壓生物力學與生理參數的影響。
針對不同操作高度下，運動學資料顯示在頭、肩、下部軀幹、髖與膝關節在三種不同的操作平面下關節角度有所不同，下壓的深度與頻率則沒有不同。動力學的資料顯示下壓的壓力亦沒有不同，平均與最大下背部力矩與脊椎壓迫力量在高位操作平面最小，因此建議高位操作平面較適合有下背痛或需要長時間操作的救護員。
透過不同按壓次數與吹氣比來看施救者疲累程度，發現在生理參數上5分鐘按壓前後收縮壓與心跳均呈現顯著的增加；自覺疲累指數呈現三組有顯著的不同；平均關節角度則無不同;按壓力量方面，按壓次數與吹氣比為50：5的會在按壓兩分鐘後出現按壓力量下降；而30：2與15：2按壓力量在2分鐘前並無不同，而30：2在第5分鐘時按壓力量則顯著小於15：2。
本研究透過動作分析的方法，建立評估心外按壓的生物力學模式。提供臨床執行心肺復甦術時，如何降低下背傷害與增加操作效率的指引，並建立基本胸外按壓的運動學與運動力學的資料。

The chances of a victim surviving from a cardiac arrest are greatly increased if good quality cardiopulmonary resuscitation (CPR) is provided in time. Therefore, quality and efficiency of CPR are important issues. External chest compression is a major step of CPR to maintain circulation. It is also a repetitive and strenuous movement which is prone to make rescuer fatigue and injury. Correct body mechanics is essential for external chest compression to decrease fatigue, prevent injuring both rescuer and victim, and maintain efficiency of CPR. Assessing the body mechanics may offer a way to produce effective performance and provide strategy to reduce injury. To author’s knowledge, no studies have ever applied motion analysis method to describe biomechanics of the chest compression. The purposes of this study were: 1) to establish a biomechanical model using motion analysis method to evaluate the movement of external chest compression in professional rescuer; 2) to examine the effects of the different rescuer’s posture on human body kinematics during performing the external chest compression; 3) to compare the back loading under three different rescuer’s positions; and 4) to examine the biomechanical and physiological effects of compression-to-ventilation ratio on external chest compression performance of rescuers.
Significant differences were observed in the head, shoulder, lower trunk, hip, and knee angles between the three different heights of the CPR surface. Compression depth, applied hand push force and compression frequency were not significantly different. The mean and maximal low back moment and compression force at high table were significantly smaller than those at low table and floor. Thus, high table positioning may decrease the chance of low back pain and is suggested to be used for CPR performed by inexperienced resuscitators, those with back injury, or those requiring a long operating duration.
The effects of different compression to ventilation ratio (C/V ratio) were assessed. The comparison of physiologic variables before and after external chest compression (ECC) indicates that heart rate and systolic blood pressure increased significantly during each period of ECC. The measurements of angles revealed no significant difference in all joints. The applied hand push force may decrease after 4 minutes of CPR at a c/v ratio of 30:2 and after 2 minutes of CPR at 50:5 ratio. The force delivered by 30:2 was similar to that delivered at 15:2 for 2 minutes; it was lower after 5 minutes of ECC.
This study developed a biomechanical model to analyze the characteristics of the external chest compression, to understand how to decrease the risk of low back loading, and to suggest an efficient compression to ventilation ratio.

1. Work practices guide for manual lifting. Cincinnati, Ohio: U.S. Dept. of Health and Human Services, National Institute for Occupational Safety and Health 1981.
2. Guidelines for cardiopulmonary resuscitation and emergency cardiac care. Emergency Cardiac Care Committee and Subcommittees, American Heart Association. Part II. Adult basic life support. Jama. Oct 28 1992;268(16):2184-2198.
3. 2005 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care. Circulation. Dec 13 2005;112(24 Suppl):IV1-203.
4. 2005 International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science with Treatment Recommendations. Part 2: Adult basic life support. Resuscitation. Nov-Dec 2005;67(2-3):187-201.
5. Cardiopulmonary resuscitation by bystanders with chest compression only (SOS-KANTO): an observational study. Lancet. Mar 17 2007;369(9565):920-926.
6. Abel R, Rupp R, Sutherland D. Quantifying the variability of a complex motor task specifically studying the gait of dyskinetic CP children. Gait Posture. Feb 2003;17(1):50-58.
7. Adams MA, Dolan P. Time-dependent changes in the lumbar spine's resistance to bending. Clin Biomech (Bristol, Avon). Jun 1996;11(4):194-200.
8. Ashton A, McCluskey A, Gwinnutt CL, Keenan AM. Effect of rescuer fatigue on performance of continuous external chest compressions over 3 min. Resuscitation. Nov 2002;55(2):151-155.
9. Association AH. 2002 Heart and Stroke Statistical Update: Dallas, TX: American Heart Association; 2002.
10. Babbs CF, Voorhees WD, Fitzgerald KR, Holmes HR, Geddes LA. Relationship of blood pressure and flow during CPR to chest compression amplitude: evidence for an effective compression threshold. Ann Emerg Med. Sep 1983;12(9):527-532.
11. Baubin M, Haid C, Hamm P, Gilly H. Measuring forces and frequency during active compression decompression cardiopulmonary resuscitation: a device for training, research and real CPR. Resuscitation. Dec 1999;43(1):17-24.
12. Baubin M, Kollmitzer J, Pomaroli A, et al. Force distribution across the heel of the hand during simulated manual chest compression. Resuscitation. Nov 1997;35(3):259-263.
13. Baubin M, Schirmer M, Nogler M, et al. Rescuer's work capacity and duration of cardiopulmonary resuscitation. Resuscitation. Dec 1996;33(2):135-139.
14. Baubin M, Schirmer M, Nogler M, et al. Active compression-decompression cardiopulmonary resuscitation in standing position over the patient: pros and cons of a new method. Resuscitation. Feb 1997;34(1):7-10.
15. Berg RA, Kern KB, Hilwig RW, Ewy GA. Assisted ventilation during 'bystander' CPR in a swine acute myocardial infarction model does not improve outcome. Circulation. Dec 16 1997;96(12):4364-4371.
16. Berquer R, Smith WD, Davis S. An ergonomic study of the optimum operating table height for laparoscopic surgery. Surg Endosc. Mar 2002;16(3):416-421.
17. Bjorshol CA, Soreide E, Torsteinbo TH, Lexow K, Nilsen OB, Sunde K. Quality of chest compressions during 10min of single-rescuer basic life support with different compression: ventilation ratios in a manikin model. Resuscitation. Apr 2008;77(1):95-100.
18. Black CJ, Busuttil A, Robertson C. Chest wall injuries following cardiopulmonary resuscitation. Resuscitation. Dec 2004;63(3):339-343.
19. Bohm K, Rosenqvist M, Herlitz J, Hollenberg J, Svensson L. Survival is similar after standard treatment and chest compression only in out-of-hospital bystander cardiopulmonary resuscitation. Circulation. Dec 18 2007;116(25):2908-2912.
20. Borg G. Psychophysical scaling with applications in physical work and the perception of exertion. Scand J Work Environ Health. 1990;16 Suppl 1:55-58.
21. Buchanan JJ. Learning a single limb multijoint coordination pattern: the impact of a mechanical constraint on the coordination dynamics of learning and transfer. Exp Brain Res. May 2004;156(1):39-54.
22. Callaghan JP, Salewytsch AJ, Andrews DM. An evaluation of predictive methods for estimating cumulative spinal loading. Ergonomics. Jul 15 2001;44(9):825-837.
23. Cholewicki J, McGill SM. Mechanical stability of the in vivo lumbar spine: implications for injury and chronic low back pain. Clin Biomech (Bristol, Avon). Jan 1996;11(1):1-15.
24. Chou SW, Wong AM, Leong CP, Hong WS, Tang FT, Lin TH. Postural control during sit-to stand and gait in stroke patients. Am J Phys Med Rehabil. Jan 2003;82(1):42-47.
25. Christensen SF, Stadeager C, Siemkowicz E. Estimation of cerebral blood flow during cardiopulmonary resuscitation in humans. Resuscitation. Apr 1990;19(2):115-123.
26. Claude LN, Solomonow M, Zhou BH, Baratta RV, Zhu MP. Neuromuscular dysfunction elicited by cyclic lumbar flexion. Muscle Nerve. Mar 2003;27(3):348-358.
27. Claytor RP. Stress reactivity: hemodynamic adjustments in trained and untrained humans. Med Sci Sports Exerc. Jul 1991;23(7):873-881.
28. Claytor RP, Cox RH, Howley ET, Lawler KA, Lawler JE. Aerobic power and cardiovascular response to stress. J Appl Physiol. Sep 1988;65(3):1416-1423.
29. Cummins RO, Eisenberg MS, Hallstrom AP, Litwin PE. Survival of out-of-hospital cardiac arrest with early initiation of cardiopulmonary resuscitation. Am J Emerg Med. Mar 1985;3(2):114-119.
30. de Leva P. Adjustments to Zatsiorsky-Seluyanov's segment inertia parameters. J Biomech. Sep 1996;29(9):1223-1230.
31. de Looze MP, Toussaint HM, van Dieen JH, Kemper HC. Joint moments and muscle activity in the lower extremities and lower back in lifting and lowering tasks. J Biomech. Sep 1993;26(9):1067-1076.
32. de Looze MP, Zinzen E, Caboor D, et al. Effect of individually chosen bed-height adjustments on the low-back stress of nurses. Scand J Work Environ Health. Dec 1994;20(6):427-434.
33. Deschilder K, De Vos R, Stockman W. The effect on quality of chest compressions and exhaustion of a compression--ventilation ratio of 30:2 versus 15:2 during cardiopulmonary resuscitation--a randomised trial. Resuscitation. Jul 2007;74(1):113-118.
34. Dickey JP, McNorton S, Potvin JR. Repeated spinal flexion modulates the flexion-relaxation phenomenon. Clin Biomech (Bristol, Avon). Nov 2003;18(9):783-789.
35. Dolan P, Adams MA. Repetitive lifting tasks fatigue the back muscles and increase the bending moment acting on the lumbar spine. J Biomech. Aug 1998;31(8):713-721.
36. Dorph E, Wik L, Stromme TA, Eriksen M, Steen PA. Quality of CPR with three different ventilation:compression ratios. Resuscitation. Aug 2003;58(2):193-201.
37. Dorph E, Wik L, Stromme TA, Eriksen M, Steen PA. Oxygen delivery and return of spontaneous circulation with ventilation:compression ratio 2:30 versus chest compressions only CPR in pigs. Resuscitation. Mar 2004;60(3):309-318.
38. Gallagher S, Marras WS, Litsky AS, Burr D. Torso flexion loads and the fatigue failure of human lumbosacral motion segments. Spine. Oct 15 2005;30(20):2265-2273.
39. Galli M, Crivellini M, Santambrogio GC, Fazzi E, Motta F. Short-term effects of "botulinum toxin a" as treatment for children with cerebral palsy: kinematic and kinetic aspects at the ankle joint. Funct Neurol. Oct-Dec 2001;16(4):317-323.
40. Granata KP, Marras WS. Relation between spinal load factors and the high-risk probability of occupational low-back disorder. Ergonomics. Sep 1999;42(9):1187-1199.
41. Granata KP, Wilson SE. Trunk posture and spinal stability. Clin Biomech (Bristol, Avon). Oct 2001;16(8):650-659.
42. Granata KR, Bennett BC. Low-back biomechanics and static stability during isometric pushing. Hum Factors. Fall 2005;47(3):536-549.
43. Grant S, Aitchison T, Henderson E, et al. A comparison of the reproducibility and the sensitivity to change of visual analogue scales, Borg scales, and Likert scales in normal subjects during submaximal exercise. Chest. Nov 1999;116(5):1208-1217.
44. Greingor JL. Quality of cardiac massage with ratio compression-ventilation 5/1 and 15/2. Resuscitation. Dec 2002;55(3):263-267.
45. Gruben KG, Guerci AD, Halperin HR, Popel AS, Tsitlik JE. Sternal force-displacement relationship during cardiopulmonary resuscitation. J Biomech Eng. May 1993;115(2):195-201.
46. Hagen KB, Harms-Ringdahl K. Ratings of perceived thigh and back exertion in forest workers during repetitive lifting using squat and stoop techniques. Spine. Nov 15 1994;19(22):2511-2517.
47. Hagen KB, Harms-Ringdahl K. Ratings of perceived thigh and back exertion in forest workers during repetitive lifting using squat and stoop techniques. Spine (Phila Pa 1976). Nov 15 1994;19(22):2511-2517.
48. Hallstrom A, Cobb L, Johnson E, Copass M. Cardiopulmonary resuscitation by chest compression alone or with mouth-to-mouth ventilation. N Engl J Med. May 25 2000;342(21):1546-1553.
49. Handley AJ, Handley SA. Improving CPR performance using an audible feedback system suitable for incorporation into an automated external defibrillator. Resuscitation. Apr 2003;57(1):57-62.
50. Handley AJ, Monsieurs KG, Bossaert LL. European Resuscitation Council Guidelines 2000 for Adult Basic Life Support. A statement from the Basic Life Support and Automated External Defibrillation Working Group(1) and approved by the Executive Committee of the European Resuscitation Council. Resuscitation. Mar 2001;48(3):199-205.
51. Hazinski MF, Nadkarni VM, Hickey RW, O'Connor R, Becker LB, Zaritsky A. Major changes in the 2005 AHA Guidelines for CPR and ECC: reaching the tipping point for change. Circulation. Dec 13 2005;112(24 Suppl):IV206-211.
52. Heidenreich JW, Berg RA, Higdon TA, Ewy GA, Kern KB, Sanders AB. Rescuer fatigue: standard versus continuous chest-compression cardiopulmonary resuscitation. Acad Emerg Med. Oct 2006;13(10):1020-1026.
53. Hightower D, Thomas SH, Stone CK, Dunn K, March JA. Decay in quality of closed-chest compressions over time. Ann Emerg Med. Sep 1995;26(3):300-303.
54. Ho WH, Lee CC, Shiang TY. The study of segment of human body of Taiwanese young people from MRI. Journal of Medical and Biological Engineering. 2003;24:s1-s6.
55. Jones AY. Can cardiopulmonary resuscitation injure the back? Resuscitation. Apr 2004;61(1):63-67.
56. Jones AY, Lee RY. Cardiopulmonary resuscitation and back injury in ambulance officers. Int Arch Occup Environ Health. Apr 13 2005.
57. Kotajarvi BR, Sabick MB, An KN, Zhao KD, Kaufman KR, Basford JR. The effect of seat position on wheelchair propulsion biomechanics. J Rehabil Res Dev. May 2004;41(3B):403-414.
58. Kumar S. Cumulative load as a risk factor for back pain. Spine. Dec 1990;15(12):1311-1316.
59. Larsen PD, Perrin K, Galletly DC. Patterns of external chest compression. Resuscitation. Jun 2002;53(3):281-287.
60. Lederer W, Mair D, Rabl W, Baubin M. Frequency of rib and sternum fractures associated with out-of-hospital cardiopulmonary resuscitation is underestimated by conventional chest X-ray. Resuscitation. Feb 2004;60(2):157-162.
61. Lin MR, Tsauo JY, Wang JD. Determinants of Economic Cost Related to Low Back Pain among Nurses at a University Hospital. Int J Occup Environ Health. Oct 1996;2(4):257-263.
62. Lorme KJ, Naqvi SA. Comparative analysis of low-back loading on chiropractors using various workstation table heights and performing various tasks. J Manipulative Physiol Ther. Jan 2003;26(1):25-33.
63. Lurie KG, Coffeen P, Shultz J, McKnite S, Detloff B, Mulligan K. Improving active compression-decompression cardiopulmonary resuscitation with an inspiratory impedance valve. Circulation. Mar 15 1995;91(6):1629-1632.
64. Lurie KG, Mulligan KA, McKnite S, Detloff B, Lindstrom P, Lindner KH. Optimizing standard cardiopulmonary resuscitation with an inspiratory impedance threshold valve. Chest. Apr 1998;113(4):1084-1090.
65. Magnusson M, Granqvist M, Jonson R, et al. The loads on the lumbar spine during work at an assembly line. The risks for fatigue injuries of vertebral bodies. Spine. Aug 1990;15(8):774-779.
66. Marras WS, Parakkat J, Chany AM, Yang G, Burr D, Lavender SA. Spine loading as a function of lift frequency, exposure duration, and work experience. Clin Biomech (Bristol, Avon). May 2006;21(4):345-352.
67. McCarthy P. Take the pain out of CPR training. Rn. Jun 1995;58(6):17-20.
68. McConvill JT, Churchill TD, eds. Anthropometric relationships of body and body segment moments of inertia: Air force aerospace medical reseach laboratory; 1980. Kaleps I, Clauser EC, eds.
69. McGill SM, Norman RW, Cholewicki J. A simple polynomial that predicts low-back compression during complex 3-D tasks. Ergonomics. Sep 1996;39(9):1107-1118.
70. McQuade KJ, Hwa Wei S, Smidt GL. Effects of local muscle fatigue on three-dimensional scapulohumeral rhythm. Clin Biomech (Bristol, Avon). Apr 1995;10(3):144-148.
71. Natarajan RN, Williams JR, Andersson GB. Recent advances in analytical modeling of lumbar disc degeneration. Spine. Dec 1 2004;29(23):2733-2741.
72. Norman R, Wells R, Neumann P, Frank J, Shannon H, Kerr M. A comparison of peak vs cumulative physical work exposure risk factors for the reporting of low back pain in the automotive industry. Clin Biomech (Bristol, Avon). Dec 1998;13(8):561-573.
73. Ochoa FJ, Ramalle-Gomara E, Lisa V, Saralegui I. The effect of rescuer fatigue on the quality of chest compressions. Resuscitation. Jun 1998;37(3):149-152.
74. Odegaard S, Saether E, Steen PA, Wik L. Quality of lay person CPR performance with compression: ventilation ratios 15:2, 30:2 or continuous chest compressions without ventilations on manikins. Resuscitation. Dec 2006;71(3):335-340.
75. Paul JA, Frings-Dresen MH, Salle HJ, Rozendal RH. Pregnant women and working surface height and working surface areas for standing manual work. Appl Ergon. Apr 1995;26(2):129-133.
76. Perkins GD, Benny R, Giles S, Gao F, Tweed MJ. Do different mattresses affect the quality of cardiopulmonary resuscitation? Intensive Care Med. Dec 2003;29(12):2330-2335.
77. Riera SQ, Gonzalez BS, Alvarez JT, Fernandez Mdel M, Saura JM. The physiological effect on rescuers of doing 2min of uninterrupted chest compressions. Resuscitation. Jul 2007;74(1):108-112.
78. Rudy TE, Boston JR, Lieber SJ, Kubinski JA, Stacey BR. Body motion during repetitive isodynamic lifting: a comparative study of normal subjects and low-back pain patients. Pain. Sep 2003;105(1-2):319-326.
79. Sanders AB, Kern KB, Berg RA, Hilwig RW, Heidenrich J, Ewy GA. Survival and neurologic outcome after cardiopulmonary resuscitation with four different chest compression-ventilation ratios. Ann Emerg Med. Dec 2002;40(6):553-562.
80. Sbriccoli P, Yousuf K, Kupershtein I, et al. Static load repetition is a risk factor in the development of lumbar cumulative musculoskeletal disorder. Spine. Dec 1 2004;29(23):2643-2653.
81. Shultz JJ, Mianulli MJ, Gisch TM, Coffeen PR, Haidet GC, Lurie KG. Comparison of exertion required to perform standard and active compression-decompression cardiopulmonary resuscitation. Resuscitation. Feb 1995;29(1):23-31.
82. Skotte JH. Estimation of low back loading on nurses during patient handling tasks: the importance of bedside reaction force measurement. J Biomech. 2001;34(2):273-276.
83. Slawinski JS, Billat VL. Difference in mechanical and energy cost between highly, well, and nontrained runners. Med Sci Sports Exerc. Aug 2004;36(8):1440-1446.
84. Taimela S, Kankaanpaa M, Luoto S. The effect of lumbar fatigue on the ability to sense a change in lumbar position. A controlled study. Spine. Jul 1 1999;24(13):1322-1327.
85. Thompson RG, Hallstrom AP, Cobb LA. Bystander-initiated cardiopulmonary resuscitation in the management of ventricular fibrillation. Ann Intern Med. May 1979;90(5):737-740.
86. Turner I, Turner S, Armstrong V. Does the compression to ventilation ratio affect the quality of CPR: a simulation study. Resuscitation. Jan 2002;52(1):55-62.
87. Unnithan VB, Dowling JJ, Frost G, Bar-Or O. Role of mechanical power estimates in the O2 cost of walking in children with cerebral palsy. Med Sci Sports Exerc. Dec 1999;31(12):1703-1708.
88. van der Linden ML, Hazlewood ME, Aitchison AM, Hillman SJ, Robb JE. Electrical stimulation of gluteus maximus in children with cerebral palsy: effects on gait characteristics and muscle strength. Dev Med Child Neurol. Jun 2003;45(6):385-390.
89. Voorhees WD, Babbs CF, Tacker WA, Jr. Regional blood flow during cardiopulmonary resuscitation in dogs. Crit Care Med. Mar 1980;8(3):134-136.
90. Wik L, Thowsen J, Steen PA. An automated voice advisory manikin system for training in basic life support without an instructor. A novel approach to CPR training. Resuscitation. Aug 2001;50(2):167-172.
91. Wright FV, Sheil EM, Drake JM, Wedge JH, Naumann S. Evaluation of selective dorsal rhizotomy for the reduction of spasticity in cerebral palsy: a randomized controlled tria. Dev Med Child Neurol. Apr 1998;40(4):239-247.
92. Yannopoulos D, Aufderheide TP, Gabrielli A, et al. Clinical and hemodynamic comparison of 15:2 and 30:2 compression-to-ventilation ratios for cardiopulmonary resuscitation. Crit Care Med. May 2006;34(5):1444-1449.