Document resource
Introduction We explored the failure rate of WatchPAT home sleep studies which uses peripheral arterial tone (PAT). PAT contraindications include medications (alpha blockers, phosphodiesterase inhibitors and long-acting nitrates), and some medical conditions (peripheral neuropathy, vasculopathy, cardiac conditions and hypertension. However, there may be other reasons including short studies, data failures or other failures.Methods We reviewed 4287 consecutive WatchPAT (Itamar, Netherlands) studies and categorised them into (OK) no failures, (Partial) partial failures (where >1 channels failed for >1 hour but clinical outcome unaffected and (Fail) fully failed where was outcome affected. Subject characteristics were M: F = 71:68, Median age = 45.0 (17.3) years, Overweight (14.4%), Obese (72.6%).Results 297 (6.9%) had either partial (3.9%) or full (3.0%) failed studies. 59.4% of the failed studies required a repeat study (4.1% of studies). (3.2%) of the failed studies were caused by PAT signal failure with full failure (72.7%) or partial failure (27.3%). Relevant patient clinical details (age, BMI, BP and sex) with conditions or medications were taken from the electronic record to identify PAT contraindications.25% of full fails had total data failure too, and 17% were total fails and short studies. Study outcomes showed that most clinical outcomes were for moderate (6.8%) or severe (15/7%) OSA. The rate of patients with PAT contraindications (figure 1) shows that the main contraindications were hypertension (29.5%), Type 2 diabetes (22.3%) and cardiac conditions (17.3%). <5% contraindicated medications were taken by patients in failed studies.Abstract P72 Figure 1(A) WatchPAT fail rates by channel (n=293); (B) ContraindicationsConclusions Failed PAT studies account for only 6.9% of studies with PAT signal failure causing 3.2% of failures.Failed PAT studies resulted from short studies (43%), failed PAT signal (35%) or failed data collection, or several factors contributing.Usual contraindicated medications and clinical contraindications accounted for few failed studies.Most PAT study failures happened in patients with a history of hypertension, Type 2 diabetes or cardiac conditions.