ATS Pulmonary Function Laboratory Manual

ATS Pulmonary Function Laboratory Management & Procedure Manual | 3rd Edition

8. If the patient cannot maintain a tight lip seal, another person can use their fingers to secure the patient’s lips. Facial muscle weakness, which is often associated with generalized neuromuscular disease, can cause problems in this test. Technician-aided lip compression has been reported to produce higher Pemax than lip compression done by the patient (12). 9. Patients may obtain higher values when incorrect procedures are performed. “Cheating” can occur on Pimax when a patient “sucks in” forcefully with a closed glottis. The pressure is generated by the oral/fa- cial muscles and can be higher than pressures generated by respiratory muscles. Conversely, in the Pemax maneuver, pumping the cheeks against a closed glottis may produce higher pressures inappropriately. Clear instructions with proper demonstration by the technician help to standardize the technique and obtain accurate results (12). 10. Several studies have reported maximum static airway pressures in healthy adults and adolescents (3, 7, 8, 14–18). The range in reported healthy values is broad, likely due to population and methodology differ- ences, and the coefficient of variation when performing this test in healthy patients is approximately 10%. Appendix 11.1 lists some values reported in healthy individuals. 11. Respiratory muscle force may also be assessed by measuring changes in pleural pressure with an esopha- geal catheter. 12. Assessment of diaphragm strength can be made by measuring abdominal and esophageal pressures via balloon-tipped catheters placed in the stomach and esophagus, and then calculating transdiaphragmatic pressure (Pdi). 13. Different mouthpiece interfaces do not result in significant differences in Pimax and Pemax (19). References 1. Barnes TA. Respiratory care practice. St. Louis: Year Book Medical Publishers; 1988. pp. 68–71. 2. Wilson AF, editor. Pulmonary function testing: indications and interpretations. Orlando: Grune & Stratton; 1985. pp. 125–136. 3. Black LF, Hyatt RE. Maximal respiratory pressures: normal values and relationship to age and sex. Am Rev Respir Dis 1969;99:696–702. 4. Clausen JL, editor. Pulmonary function testing; guidelines and controversies. New York: Academic Press; 1982. pp. 187–191. 5. American Thoracic Society/European Respiratory Society. ATS/ERS statement on respiratory muscle testing. Am J Respir Crit Care Med 2002;166:518–624. 6. Nava S, Ambrosino N, Crotti P, Fracchia C, Rampulla C. Recruitment of some respiratory muscles during three maximal inspiratory manoeuveres. Thorax 1993;48:702–707. 7. Vincken W, Ghezzo H, Cosio MG. Maximal static respiratory pressures in adults: normal values and their relationship to determinants of respiratory function. Bull Eur Physiopathol Respir 1987;23:435– 439. 8. Enright PL, Kronmal RA, Manolino TA, et al . Respiratory muscle strength in the elderly: correlates and reference values. Am J Respir Crit Care Med 1994;149:430–438. 9. Polkey MI, Green M, Moxham J. Measurement of respiratory muscle strength. Thorax 1995;50:1131– 1135. 10. Celli BR. Clinical and physiologic evaluation of respiratory muscle function. Clin Chest Med 1989;10:199–214.

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