title: Paradoxical reaction of blood pressure on sleep apnoea patients treated with Positive Airway Pressure.
abstract: BACKGROUND
  Obstructive Sleep Apnoea Syndrome (OSAS) patients may develop hypertension and Positive Airway Pressure (PAP) is an effective treatment in blood pressure (BP) control.
  
  
  OBJECTIVE
  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, defined 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 coefficient.
  
  
  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 significant 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 specific characteristics were identified 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 β1-adrenoreceptors with different BP responses to ventilatory support. More studies are needed to clarify the cause of this paradoxical response.
authors.affiliation: Pneumology Department, Hospitais da Universidade de Coimbra, Coimbra, Portugal. cl_loureiro@hotmail.com
authors.forename: C
authors.initials: C
authors.lastname: Chaves Loureiro
authors.forename: M
authors.initials: M
authors.lastname: Drummond
authors.forename: J C
authors.initials: JC
authors.lastname: Winck
authors.forename: J
authors.initials: J
authors.lastname: Almeida
mesh_terms: D001794:Blood Pressure; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011175:Positive-Pressure Respiration; D012189:Retrospective Studies; D012891:Sleep Apnea Syndromes / Q000503:physiopathology* / Q000628:therapy*