Capnography screening for sleep apnea in patients with acute stroke

Abstract

Sleep apnea syndrome (SAS) is a prominent clinical feature in acute stroke patients. Diagnosis is usually established by polysomnography or cardio-respiratory polygraphy (CRP). Both diagnostic procedures produce high costs, are dependent on the access to a specialized sleep laboratory, and are poorly tolerated by patients with acute stroke. In this study we therefore investigated whether capnography may work as a simple screening tool in this context. In addition to conventional CRP, 27 patients with acute stroke were studied with capnography provided by our standard monitoring system. The trend graphs of the end-tidal CO(2) values (EtCO(2)) were used to determine the capnography-based estimate of the apnea-hypopnea index (AHI(CO2)). Index events were scored when the EtCO(2) value dropped for > 50% of the previous baseline value. We found that the AHI(CO2) correlated significantly with the apnea-hypopnea index measured with conventional CRP (AHI(CRP)) (r = 0.94; p < 0.001). An AHI(CO2) > 5 turned out to be highly predictive of an AHI(CRP) > 10. According to our findings, routinely acquired capnography may provide a reliable estimate of the AHI(CRP). The equipment needed for this screening procedure is provided by the monitoring systems of most intensive care units and stroke units where stroke patients are regularly treated during the first days of their illness. Therefore, early diagnosis of SAS in these patients is made substantially easier.

C-Reactive Protein and Fibrinogen in Acute Stroke Patients with and without Sleep Apnea

“…Sleep apnea (SA) is a predominant feature of acute stroke being present in up to 90% of patients [1,2,3,4,5,6,7,8,9,10,11,12] as compared to 4% in the general middle-aged adult population [13]. In a large prospective observational study, SA increased the risk of stroke or death independent of other known risk factors [14].…”

Pre‐screening of sleep‐disordered breathing after stroke: A systematic review

“…The studies were conducted in the following countries: Brazil, Egypt, Austria, India, USA, the Netherlands, Taiwan, Canada, Germany, the United States of America and Australia (Aaronson et al., ; Bassetti et al., ; Boulos et al., ; Broadley et al., ; Camilo et al., ; Chen et al., ; Dziewas et al., ; Elkholy et al., ; Katzan et al., ; Kotzian et al., ; Srijithesh et al., ). The majority of the studies were conducted in hospital settings: six in neurology units (Boulos et al., ; Broadley et al., ; Dziewas et al., ; Elkholy et al., ; Kotzian et al., ), one in an emergency unit (Camilo et al., ), two in rehabilitation units (Aaronson et al., ; Chen et al., ), one in a care referral teaching unit (Srijithesh et al., ), and one in a sleep clinic (Katzan et al., ). Apnea and hypopneas were frequent in the studied patients as the reported prevalence ranged from 46% to 77%.…”

Day–night Differences in Oxygen Saturation and the Frequency of Desaturations in the First 24 Hours in Patients With Acute Stroke

“…The median (range) respiratory rate was 20 (14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30) breaths/min during the day and 18 breaths/min at night (P Ͻ .01, Wilcoxon test). There was a strong positive correlation between daytime and nighttime respiratory rates (Spearman's r ϭ 0.78, P Ͻ .001).…”

“…Four of the patients (10%) in the study were taking sedatives, and none of the patients were taking hypnotics. The median (range) GCS score was 15 (10)(11)(12)(13)(14)(15) and the median (range) SSS score was 31 (4-56) at recruitment. There were 11 patients (28%) with total anterior circulation syndrome, 12 (30%) with partial anterior circulation syndrome, and 17 (42%) with lacunar syndrome.…”

“…6,7 Guidelines for stroke management recommend monitoring of oxygen saturation as part of routine poststroke care. 8,9 Much of the recent research relating to poststroke breathing disorders has concentrated on sleep apnea [10][11][12][13][14][15] and was based on clinical studies using nocturnal polysomnography. Because the presumption is that sleep apnea is a problem that occurs at night when the patient sleeps, and because polysomnography involves multichannel monitoring, which would interfere with daytime activities and rehabilitation, data are only collected at night.…”