title: Impaired exercise ventilatory mechanics with the self-contained breathing apparatus are improved with heliox.
abstract: The effect of the self-contained breathing apparatus (SCBA) with compressed air (BA-A) on ventilatory mechanics, work of breathing (WOB), pulmonary function, and respiratory muscle fatigue, was compared with that of a low resistance breathing valve (LRV). Further, the effect of unloading the respiratory muscles with heliox with the SCBA (BA-H) was compared with BA-A and LRV. Twelve men completed three randomized exercise trials on separate days, each consisting of three 10 min bouts of stepping exercise (Bouts 1, 2, and 3) separated by a 5 min recovery. Subjects wore firefighter protective equipment including the SCBA. At rest, FEV(1) and peak expiratory flow rates were lower with BA-A than with LRV, but were higher with BA-H than either with BA-A or LRV. After Bout 3, expiratory reserve volume, expiratory resistive WOB, and inspiratory elastic WOB were increased in BA-A compared to LRV but these were lower with BA-H compared to BA-A. After Bout 3, maximal inspiratory and expiratory pressures were reduced with BA-A, but not with LRV or BA-H. In summary, we found that the SCBA reduced resting pulmonary function, and increased expiratory reserve volume, work of breathing, and respiratory muscle fatigue during stepping exercise, and these changes can be reduced with the use of heliox.
authors: Department of Medicine, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada, T6G 2B7.
authors: Scott J
authors: SJ
authors: Butcher
authors: Richard L
authors: RL
authors: Jones
authors: Jonathan R
authors: JR
authors: Mayne
authors: Timothy C
authors: TC
authors: Hartley
authors: Stewart R
authors: SR
authors: Petersen
mesh_terms: D000328:Adult; D000399:Air Pressure; D001831:Body Temperature; D004947:Esophagus / Q000502:physiology; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test; D006339:Heart Rate / Q000502:physiology; D006371:Helium / Q000494:pharmacology*; D006801:Humans; D008170:Lung Compliance / Q000502:physiology; D008176:Lung Volume Measurements; D008297:Male; D008448:Maximal Expiratory Flow Rate / Q000502:physiology; D018763:Muscle Fatigue / Q000502:physiology; D053580:Muscle Strength / Q000502:physiology; D010100:Oxygen / Q000494:pharmacology*; D011482:Protective Devices; D012129:Respiratory Function Tests; D015656:Respiratory Mechanics / Q000187:drug effects* / Q000502:physiology*; D012132:Respiratory Muscles / Q000502:physiology; D013147:Spirometry; D035441:Thoracic Wall / Q000502:physiology; D012122:Ventilators, Mechanical; D014939:Work of Breathing / Q000502:physiology
chemical_list: D006371:Helium; C038949:heliox; D010100:Oxygen
references: J Appl Physiol (1985). 1986 Jul;61(1):138-49
references: 3733599
references: J Appl Physiol (1985). 1995 May;78(5):1710-9
references: 7649904
references: Can J Appl Physiol. 2003 Dec;28(6):910-26
references: 14992128
references: J Appl Physiol (1985). 1999 Apr;86(4):1357-66
references: 10194223
references: Eur Respir J. 1998 Jun;11(6):1369-75
references: 9657581
references: Respir Physiol Neurobiol. 2002 Oct 23;133(1-2):139-51
references: 12385739
references: Chest. 1999 Aug;116(2):488-503
references: 10453881
references: Am Rev Respir Dis. 1981 Jun;123(6):659-64
references: 7271065
references: J Appl Physiol Respir Environ Exerc Physiol. 1980 Sep;49(3):506-10
references: 7204174
references: Med Sci Sports Exerc. 1980;12(5):380-4
references: 7453518
references: Ergonomics. 2006 Aug 15;49(10):911-20
references: 16803723
references: Med Sci Sports Exerc. 1996 Sep;28(9):1129-37
references: 8883000
references: J Appl Physiol (1985). 1993 May;74(5):2552-8
references: 8335591
references: Aviat Space Environ Med. 2003 Oct;74(10):1040-7
references: 14556564
references: Med Sci Sports Exerc. 2004 May;36(5):780-6
references: 15126710
references: J Appl Physiol (1985). 2004 Nov;97(5):1637-42
references: 15234959
references: Am J Respir Crit Care Med. 2001 Sep 1;164(5):770-7
references: 11549531
references: Am J Respir Crit Care Med. 2006 Oct 1;174(7):763-71
references: 16840742
references: Am Rev Respir Dis. 1969 May;99(5):696-702
references: 5772056
references: Am J Respir Crit Care Med. 1996 Oct;154(4 Pt 1):938-44
references: 8887589
references: Chest. 1988 Nov;94(5):976-82
references: 3180901
references: Am J Respir Crit Care Med. 1995 Sep;152(3):1107-36
references: 7663792
references: Appl Physiol Nutr Metab. 2006 Dec;31(6):693-701
references: 17213883
references: Ergonomics. 2004 Feb 26;47(3):324-9
references: 14668166
references: Ergonomics. 2002 Oct 10;45(12):829-39
references: 12487685
references: Can J Appl Physiol. 2005 Oct;30(5):507-19
references: 16293900
references: J Appl Physiol. 1964 Mar;19:212-6
references: 14155284
references: J Clin Invest. 1963 Nov;42:1705-13
references: 14083161
references: J Appl Physiol (1985). 2006 Feb;100(2):414-20
references: 16239617
references: J Appl Physiol (1985). 1996 Apr;80(4):1270-8
references: 8926256
references: Am J Respir Crit Care Med. 2001 Apr;163(5):1128-34
references: 11316648
references: J Appl Physiol (1985). 2002 May;92(5):1953-63
references: 11960945