Method for manipulating peak flow measurements producing falsely raised readings

Methods by which patients can artificially produce raised peak flow measure ments have been described. We recently observed a patient manipulating the peak flow meter in a way that had not been described before. A study was th erefore undertaken to determine if this technique could repeatedly produce clinically significant changes in peak flow readings. Fifteen adults, using a mini-Wright peak flow meter, made five measurements using the correct te chnique followed by five manipulated measurements under observation. Signif icant increases in peak flow measurements were observed in 14 of the 15 sub jects. The mean increase in peak flow rate using the incorrect technique wa s 56% (range -4% to 86%). Clinicians should be aware that patients might em ploy this technique to manipulate measurements which could have consequence s for management.