Paradoxical reaction of blood pressure on sleep apnoea patients treated with Positive Airway Pressure [Reacção paradoxal da pressão arterial ao tratamento com pressão positiva na via aérea em doentes com apneia do sono]

Introduction: obstructive sleep apnoea syndrome (osas) patients may develop hypertension and positive airway pressure (pap) is an effective treatment in blood pressure (bp) control. objectives: analyse a hypertensive osas population with unexpected bp rise after pap usage and verify correlations between bp rise,either with osas severity index or nocturnal ventilatory support compliance. methods: descriptive,retrospective analysis of 30 patients with pap treated osa,for one year,on average,and with previous controlled hypertension,who developed a rise in bp,defi ned as augmentation of > 5 mmhg in systolic (sbp) and/or diastolic bp (dbp),after pap usage. co-relational analysis of bp increase,with osas severity indexes and therapy compliance,using pearson coeffi cient. results: of 508 consecutive patients followed in our department,treated with nocturnal ventilatory support,30 evolved with bp rise after initiating treatment (age 58 ± 10.8 years; apnoea-hypopnoea index [ahi],46.1 ± 18.68). after pap usage,mean blood pressure (mbp),systolic bp (sbp) and diastolic bp (dbp) variation was 16 ± 15 mmhg,20 ± 25 mmhg and 6 ± 19.4 mmhg,respectively. no patient showed signifi cant bmi increase. epworth sleepiness scale (ess) value decreased 8.9 ± 5.48 points. mbp,sbp and dbp variations were not correlated with p90/p95,residual ahi,leaks or pap compliance. conclusions: no specifi c characteristics were identifi ed in the group who developed a rise in bp with pap usage. no correlations were found between rises in bp and osas severity indexes or pap compliance. neither bmi nor variation in wakefulness status explained the rise in bp. studies relate polymorphisms of b1-adrenoreceptors with different bp responses to ventilatory support. more studies are needed to clarify the cause of this paradoxical response. © 2010 published by elsevier españa,s.l. on behalf of sociedade portuguesa de pneumologia.