Peak expiratory flow in bed? A comparison of 3 positions

BACKGROUND: Current guidelines for the correct peak expiratory flow (PEF) maneuver include standing. In the hospital setting, PEF values are often ordered to assess response to asthma therapy for exacerbations. We have observed that the PEF is sometimes performed with the patient in bed. METHODS: Healthy adults performed the PEF maneuver in random order, standing, lying back at an 45° angle on pillows, and sitting, slumped forward 10° with legs extended. PEF was recorded for 3 attempts in each of the 3 positions. RESULTS: We enrolled 94 subjects (39 male, 55 female, mean age 24 y) in 2011. Mean PEF in the standing position (669 42 L/min) was significantly higher than in the lying back (621 42 L/min) (P < .001) and sitting (615 42 L/min) positions in males (P < .001), and, similarly, in females, standing produced a significantly higher mean PEF (462 42 L/min) than the lying back (422 42 L/min) (P < .001) and sitting (447 42 L/ min) positions (P < .05). CONCLUSIONS: Clinicians should ensure that PEF is obtained with patients out of bed and in the standing position. Key words: peak expiratory flow; asthma; correct maneuver. [Respir Care 2013;58(3):494–497. © 2013 Daedalus Enterprises]