Portable peak flow meters: physical characteristics, influence of temperature, altitude, and humidity.

摘要: Little is known about the linearity of portable peak flow meters, or physical gas factors affecting expiratory (PEF) readings. We therefore tested five meters three types in an altitude chamber (sea level to 5,500 m) and a climate at sea (7-37 degrees C) determine influence conditions on reading meters. The nonlinear response variable orifice was confirmed and, when this corrected for, readings these were found be significantly reduced by higher lower temperature. from turbine type meter not affected but low A mathematical model for could correct both their behaviour effect density (altitude, temperature humidity). showed that correction necessary differences between calibration taking measurements under normal laboratory conditions. All had impedances than recommended (0.05 kPa.l-1.s) may PEF high flows. mean uncorrected six healthy subjects measured with Mini Wright 3,000 m fell 5%, increased 12%. This increase 60% predicted fully density-dependent agreed findings other similar studies.(ABSTRACT TRUNCATED AT 250 WORDS)