Continuous positive airway pressure: mode of ventilation
Keywords:
Respiratory physiology, Continuous positive airway pressure, Respiratíon artificialAbstract
Objective
The objectíve of this study was to assess if continuous positive airway pressure promotes physiological changes in the respiratory variables that characterize it as a mode of ventilation and compare it with pressure support ventilation.
Methods
This is a prospective study with 39 adult, healthy volunteers done in a tertiary university hospital. All volunteers were monÊtored while breathing spontaneous ly with the monitor CO,SMO - Dixtal. Later, the pressure support mode was adjusted in 5cmH,O
above the positive end-expiratory pressure (of same value). After seven days, the individuaIs were submitted to the same procedures, however with application of a
continuous positive airway pressure of 7cmH,O, The ventilator brand was Dragér, model Savina®.
Results
The following respiratory variables increased: minute volume, alveolar minute volume, peak inspiratory and expiratory flows and saturation of peripheral oxygen. Tidal volume was similar in both modes but expired carbon dioxide was smaller during pressure support when compared with spontaneous breathing. This may be explained by the íncreased respiratory rate in this mode.
Conclusion
In healthy volunteers, continuous positive airway pressure induces similar physiological variations in respiratory parameters, such as pressure support when mean airway pressure corresponds. If the criterion considered for mode of ventilation is variation in
tidal volume and respiratory rate among other variables, one can conclude that continuous positive airway pressure is a type of mode of ventilation.
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References
Branson RD, Hurst JM, Dehaven CB. Mask CPAP: state of the art. Respir Care. 1985; 30(9):646-57.
Masip J, Roque M, Sánchez B, Fernéndez R, Subirana M. Expósito FA. Noninvasive ventilation in acute cardiogenic pufmonary edema. Systematic Review and Meta-analysis. JAMA. 2005; 294(24):3124-30.
Kosowsky JM, Storrow AB, Carleton SC. Continuous and bilevel positive airway pressure in the treatment of acute cardiogenic pulmonary edema. Am J Emerg Med. 2000; 18(1):91-5.
Kindgen-Mtlles D, Buhl R, Gabriel A, Bõhner H, Müller E. Nasal continuous positive airway pressure. A method to avoid endotracheal reintubation in postoperative high-risk patients with severe nonhypercapnic oxygenation failure. Chest. 2000; 117 (4): 1106-11.
Goldberg P, Reissmann H, Maltais F, Ranieri M. Gottfried SB. Efficacy of noninvasive c-PAP in COPD with acute respiratory failure. Eur Respir J. 1995; 8(11): 1894-900.
Meduri GU, Cook TR, Turner RE, Cohen M, Leeper KV. Nonlnvasive positive pressure ventilation in status asthmaticus. Chest. 1996; 110(3):767-74.
Delclaux C, Lher E, Alberti C, Mancebo J, Abroug F, Conti G, et al. Treatment of acute hypoxemic nonhypercapnic respiratory insufficiency with continuous positive airway pressure delivered by a face mask. A randomized controlled trial. JAMA. 2000: 284(18):2352-60.
National Association for Medical Direction of Respiratory Care. Clinical indications for noninvasive positive pressure ventilation in chronic respiratory failure due to restrictive lung disease, COPD, and nocturnal hypoventilation. A consensus conference report. Chest. 1999; 116(2):521-34.
Mehta S, Hill N. Noninvasive Ventilation. Am J Respir Crit Care Med. 2001 ; 163(2):540-77.
Gunduz M, Unlugenc H, Ozalevli M, Inanoglu K, Akman H. A comparative study of continuous positive airway pressure (CPAP) and Êntermittent positive pressure ventilation (IPPV} in patients with flaid chest Emerg Med J. 2005; 22(4):325-9.
III Consenso Brasileiro de Ventilação Mecânica. J Bras Pneumol. 2007; 33(Supl 2):S54-S70.
Azeredo CAC, Slutzky LC. Pressão positiva contínua nas vias aéreas (CPAP): um enfoque profilático. Rev Sulamericana Fisioter Resp. 1996; 0(0):7-15.
Bacon JP, Farney R, Jensen RJ, Walker JM, Cloward TV. Nasal continuous positive airway pressure devices do not maintain the set pressure dynamically when tested under simulated clinical conditions. Chest 2000; 118(5):1441-9.
Lindner KH, Lotz P, Ahnefeld FW, Continuous positive airway pressure effect on functional residual capacity, vital capacity and its subdivisions, Chest. 1987; 92(1):66-70.
Reissrnann HK, Ranieri VM, Goldberg E Gottfried SB Continuous positive airway pressure facilitates spontaneous breathing in weaning chronic obstructive pulmonary disease patients by improving breathing pattern and gas exchange. Int Care Med 2000; 26(12):1764-72.
Azeredo, L. Ventilação não invasiva. In: Azeredo, C.A.C- Técnicas para o desmame no ventilador mecânico. Rio de Janeiro: Manole; 2002. p.311-25.
Bishop B, Hirsch J, Thursby M. Volume, flow, and timing of each breath during positive-pressure breathing in man. J Appl Physiol. 1978; 45(4):495-501.
Leung P, Jubran A, Tobin MJ. Comparison of assisted ventilation mc,des on triggering, patient effort, and dyspnea. Am J Respir Crit Care Med. 1997; 155(6) 1940-8.
Laghi F, Karamchandani K, Tobin MJ. Influence of ventilator settings in determining respiratory frequency during mechanical ventilation. Am J Respir Crit Care Med. 1999; 160(5):1766-70.
Parthasarathy S, Jubran A, Tobin MJ. Assessment of neural inspiratory time in ventilator-supported patients. Am J Respir Crit Care Med. 2000; 162(2): 546-52.
Russell WC, Greer JR. The comfort of breathing: a study with volunteers assessing the influence of various modes of assisted ventilation, Crit Care Med 2000; 28(1 1):3645-8.
Laghi F. Segal J, Choe WK, Tobin MJ. Effect of imposed inflation time on respiratory frequency and hyperÉnflation in patients with chronic obstructive pulmonary disease. Am J RespirCrit Care Med, 2001; 163(6):1365-70.
Brirnacombe J, Keller C, Hôrmann C, Pressure-support ventilation versus continuous positive airway pressure with the laryngeaí mask airway. Anesthesiology. 2000; 92(6): 1621-3.
Gattinoni L, Vagginelli F, Chiumello D, Taccone P, Carlesso E. Physiologic rationale for ventilator setting in acute lung injury/acute respiratory distress syndrome patients. Crit Care Med. 2003; 31(Suppl 4):S300-S304.
KacMarek RM. Noninvasive positive-pressure ventilation: the little things do make the difference Respir Care. 2003; 48(10):919-21.
Maclntyre NR. Respiratory function during pressuresupport ventilation. Chest, 1986; 89 (5):677-83.
Vitacca M. Nava S. Confalonieri M. Biancho L. Porta R Clini E, et al. The appropriate setting of noninvasive pressure-support ventÊlation in stable COPD patients Chest. 2000; 118(5):1286-93.
Park M. Lorenzi Filho G, Feltrim Ml, Viecili PR, Sangean MC, Volpe M, et al, Oxygen therapy. continuous positive airway pressure, or noninvasive bilevel positive pressure ventilation in the treatment of acute cardiogenic pulmonary edema. Arq Bras Cardiol 2001; 76(4):221-5.
Urbscheit MA Bishop B, Bachofen H, Immediate effects of continuous positive pressure breathing on abdominal expiratory activity, minute ventilation, and end-tidal PCO, of conscious man. Phys Ther. 1973; 53(4):258-65.
