Jakub Radlinski

Nocturnal pulse wave attenuation is associated with office blood pressure in a population based cohort

OBJECTIVE AND BACKGROUNDnPulse wave amplitude (PWA) derived from the digital vascular bed has been used in sleep studies. The nocturnal attenuation of PWA has been shown to reflect sympathetic activation during sleep. We assessed the relationship between nocturnal PWA attenuation and office blood pressure (BP).nnnMETHODSnEighty-one subjects (46 men; age 60+/-7 years; body mass index [BMI] 28.2+/-4.3 kg/m(2); apnea hypopnea index [AHI], 25.4+/-22.6 events/h; systolic BP 137+/-15 mm Hg; diastolic BP 79+/-7 mm Hg) recruited from a population based cohort underwent simultaneous ambulatory polysomnography (PSG) and peripheral arterial tonometry (PAT) recording. Episodic attenuations of PWA derived from the pulse waveform of the PAT signal were identified and characterized. Generalized least squares regression models were used to identify the associations between median PWA attenuation (PWA.att), office BP and sleep-related disordered breathing.nnnRESULTSnWe found that the association between PWA.att and office BP was independent of gender, age, BMI, antihypertensive medication, number of attenuation episodes, AHI, oxygen desaturation 4% index (ODI4) and arousal index. Each 10% increase in PWA.att was associated with increases of 5.0 mm Hg systolic BP (P=0.02) and 3.0 mm Hg diastolic BP (P=0.005). We also found independent relationships between systolic/diastolic BP and BMI (P=0.0006/0.001), AHI (P=0.03/0.1) and ODI4 (P=0.03/0.03).nnnCONCLUSIONSnThe degree of PWA attenuation during the night is associated with office BP independent of sleep-disordered breathing. Continuous assessment of PWA during sleep may provide novel insights into cardiovascular physiology and morbidity.

A double-blind, crossover study of Doxazosin and Enalapril on peripheral vascular tone and nocturnal blood pressure in sleep apnea patients

OBJECTIVEnPulse wave attenuation, which occurs in association with obstructive sleep apnea (OSA), is sympathetically mediated. We compared the effect of Doxazosin (DO, a peripheral alpha-receptor inhibitor) and Enalapril (EN, an ACE inhibitor) on digital vasoconstriction and nocturnal blood pressure (BP) in hypertensive OSA patients.nnnMETHODSnA double-blind, crossover study comparing equipotent dosages of DO (4 mg/day for 2 weeks with 8 mg/day for an additional 2 weeks) and EN (10mg/day and 20mg/day, respectively) was undertaken in 16 male OSA patients (age 55+/-7 years, body mass index 30.1+/-3.8 kg/m(2)) with hypertension. Assessments including ambulatory 24-h BP, full-night polysomnography with simultaneous peripheral arterial tone (PAT) and beat-to-beat finger BP monitoring (Finapres) were made at the end of each treatment period. Nighttime BP and digital vasoconstrictions associated with apneic events (measured as the ratio of PAT amplitudes during and after apneas) were analyzed.nnnRESULTSnThere were no differences between the two treatments in the 24-h BP profile and OSA severity. But the nighttime average beat-to-beat finger BP was significantly higher under DO treatment (systolic BP 129+/-13 vs. 119+/-23 mm Hg, P=0.02; diastolic BP 81+/-12 vs. 74+/-14 mm Hg, P=0.04, DO and EN respectively). In a linear mixed effects regression model, the PAT ratio during apnea increased 5.3% under DO compared with EN (P<0.0001). Each percentage decrease of apneic related oxygen desaturation was associated with 0.9% decrease in the PAT ratio (P<0.0001). REM sleep was associated with 2.2% decrease of PAT ratio compared to NREM sleep (P=0.002).nnnCONCLUSIONnDigital vasoconstrictions associated with apneic events are alpha-receptor mediated. DO compared to EN has a proportionally poor effect on nocturnal BP control in OSA patients, which may be due to the enhanced sympathetic nervous system activity characteristic of this condition.

Application of impulse oscillometry in respiratory system evaluation in elderly patients.

INTRODUCTIONnSpirometry, which is a basic diagnostic tool of the respiratory system, may cause problems to patients of advanced age because of required cooperation and specific respiratory manoeuvres. Impulse oscillometry (IOS) may be an interesting alternative for spirometry as the examination is made during quiet breathing and gives information about resistive properties of the respiratory system.nnnMATERIAL AND METHODSnThis work presents the results of oscillometric measurements made in 277 patients aged 65-96 years, in whom spirometry was also performed.nnnRESULTSnResistances measured with IOS (R5, R5-R20) and the resonant frequency Fn correlated significantly with FEV1 (r = -0.503; -0.570 and -0.673, respectively). A comparison of the results from patients with airway obstruction confirmed in spirometry with those of the non-obstructed group showed highly significant differences in mean values of oscillometric parameters (p < 0.001).nnnCONCLUSIONSnAs R5-R20 is regarded as a measure of peripheral airways resistance, IOS may serve as an interesting complementary or alternative method for spirometry in elderly subjects for evaluation of the state of respiratory system.

Reference values for IOS derived R5-R20 and AX assessed from healthy polish children

There is an increasing interest in using small airways indices derived from impulse oscillometry (IOS) measurements: peripheral airways resistance defined as the difference between R5 and R20 (R5 - total respiratory system resistance, measured at 5 Hz and central resistance- R20 measured at 20 Hz) as well as area under reactance curve AX (the so called Goldman triangle). Using the data gathered for evaluating IOS normative reference equations (B. Nowowiejska, W. Tomalak, J. Radlinski et al. Transient reference values for impulse oscillometry for children aged 3-18 years. Pediatric Pulmonology 43:1193-1107, 2008) we have analysed them in order to obtain equations for R5-R20 and AX in healthy children aged 3-18 years. There were 278 boys and 348 girls. These data were analysed with four models: linear, exponential, logarithmic and multiplicative. Best fit was obtained with exponential model y=EXP(a*H + b) with height (H measured in cm) as independent variable. The correlation coefficients varied from 0.658 to 0.813. The table presents coefficients of equations for R5-R20 and AX for boys, girls and both sexes together with RSD values. We conclude that presented equations will be helpful in analyses concerning small airways properties assessed with IOS in children.