ATS GUIDELINES Bundle

Management Table 1. Recommendations Recommendations Explanations and other considerations 1A: For obese patients with sleep-disordered breathing with a high pre-test probability of having OHS, the ATS suggests measuring PaCO 2 rather than serum bicarbonate or SpO 2 to diagnose OHS. (Conditional recommendation, very low level of certainty in the evidence) Patients with a high pre-test probability of having OHS are usually severely obese with typical signs and symptoms of OHS and can be mildly hypoxemic during wake and/or significantly hypoxemic during sleep. is is a recommendation for screening for OHS in patients with sleep-disordered breathing, most typically obstructive sleep apnea (OSA). 1B: For patients with low to moderate probability of having OHS (<20%), the ATS suggests using serum bicarbonate levels to decide when to measure PaCO 2 : in patients with serum bicarbonate <27 mmol/l clinicians might forego measuring PaCO 2 , since the diagnosis of OHS in them is very unlikely. In patients with serum bicarbonate ≥27 mmol/l clinicians might need to measure PaCO 2 to confirm or rule out the diagnosis of OHS. (Conditional recommendation, very low level of certainty in the evidence) Using a 27 mmol/l threshold in serum bicarbonate in obese patients with OSA and low to moderate clinical suspicion of OHS (initial probability of OHS not more than 20%) would likely permit forgoing further testing such as arterial blood gases in those with bicarbonate level <27 mmol/l (64% to 74% of obese patients with OSA) and perform arterial blood gas analysis only in those with serum bicarbonate ≥27 mmol/l (26% to 36% of obese patients with OSA). e ATS found insufficient evidence for serum bicarbonate thresholds other than 27 mmol/l. 1C: e ATS suggests that clinicians avoid using oxygen saturation by pulse oximetry (SpO 2 ) during wakefulness to decide when to measure PaCO 2 in patients suspected of having OHS until more data about the usefulness of SpO 2 in this context become available. (Conditional recommendation, very low level of certainty in the evidence) e ATS found insufficient data to investigate the clinical usefulness of any threshold of wake SpO 2 for screening for OHS in obese patients with OSA. Guideline panel members thought that relevant studies have to be done before the clinical usefulness of wake SpO 2 in this context can be assessed. is is a temporary recommendation reflecting lack of evidence about a potentially useful intervention, rather than evidence that it is not useful. us, this recommendation should not be used as an argument against additional research and will likely change once additional data are available. 2: For stable ambulatory patients diagnosed with OHS, the ATS suggests treatment with PAP during sleep. (Conditional recommendation, very low level of certainty in the evidence) Note: Patients with symptomatic OHS who have significant comorbidities and those with chronic respiratory failure following an episode of acute-on-chronic hypercapnic respiratory failure may particularly benefit from using PAP.

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