some patients with OSA may have other co-morbid diseases including congestive heart failure or chronic renal failure, do these diseases with associated dyspnoea and difficulty in breathing frequent carousals and paroxysmal nocturnal dyspnoea (PND) alter the reading of the test, i.e. control of these conditions before PSG may give a different or better result
Yes! But in first line the causes of sleep apneas are in upper part of respiratory tractus! (Deviatio septi nasi, rhinitis, sinusitis, adenoids, ect.) Before registration of PSG and sleep apneas the the respiratory ductus must be free.
The conditions you have mentioned are influent in the result of PSG in two ways: Central apnea and variation of respiratory control ( see respiratory frive, loop gain ). The influence isn't about the difficult in breathing but in the control of ventilatory drive
PND can cause disturbed sleep & the patient may go to deeper sleep as long as otherwise. also it can cause more arousals in sleep. CHF can cause cheynes stokes respiration which is obvious in the PSG. CHF can exaggerate the hypoxia noted. However if the CHF cannot be controlled then we just go ahead & do the study. if it is an acute event of CHF then I would wait for stabilization. if it is chronic CHF, we can go ahead with the PSG. if they have sleep apnea & they have Cheynes stokes respiration, then we may have go specialized bipap machine called Auto SV or similar
Thank you all for the valuable answers. So I can recommend control of the comorbid conditions prior to PSG and CPAP titration or if can not be controlled then the optimum machine is Auto CPAP (Auto SV)
typically we recommend in lab titration study when there is CHF with OSA. during the titration initially we try on regular CPAP, if the technician notices cheynes stokes or notices significant central apnea, then we call is complex sleep apnea, then we change to Auto Servoventilation . this provides variable EPAP & Variable IPAP with a back up rate when needed. Auto Sv is a smart BIPAP machine.
Dear Dr Shabana;
We also try to control comorbidities such as CHF prior performing PSG which can interact with sleep disorder.
I recommend you to read review by White et al.
White LH, Bradley TD, Logan AG.Journal of Human Hypertension ,2014 |
Pathogenesis of obstructive sleep apnoea in hypertensive patients: role of fluid retention and nocturnal rostral fluid shift.
Best regards
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