RESUMEN
Background: Obstructive Sleep Apnea (OSA) is associated with an increased risk of cardiovascular events, including Acute Coronary Syndrome (ACS). There is conflicting evidence that suggests OSA has a cardioprotective effect (i.e., lower troponin), via ischemic pre-conditioning, in patients with ACS. Purpose: This study had two aims: (1) compare peak troponin between non-ST elevation (NSTE) ACS patients with and without moderate OSA identified using a Holter derived respiratory disturbance index (HDRDI); and (2) determine the frequency of transient myocardial ischemia (TMI) between NSTE-ACS patients with and without moderate HDRDI. Method: This was a secondary analysis. OSA events were identified from 12-lead ECG Holter recordings using QRSs, R-R intervals, and the myogram. Moderate OSA was defined as an HDRDI ≥15 events per/hour. TMI was defined as ≥1 millimeter of ST-segment ↑ or ↓, in ≥ 1 ECG lead, ≥ 1 minute. Results: In 110 NSTE-ACS patients, 39% (n=43) had moderate HDRDI. Peak troponin was higher in patients with moderate HDRDI (6.8 ng/ml yes vs. 10.2 ng/ml no; p=0.037). There was a trend for fewer TMI events, but there were no differences (16% yes vs. 30% no; p=0.081). Conclusions: NSTE-ACS patients with moderate HDRDI have less cardiac injury than those without moderate HDRDI measured using a novel ECG derived method. These findings corroborate prior studies suggesting a possible cardioprotective effect of OSA in ACS patients via ischemic pre-condition. There was a trend for fewer TMI events in moderate HDRDI patients, but there was no statistical difference. Future research should explore the underlying physiologic mechanisms of this finding.
RESUMEN
INTRODUCTION: The prevalence of OSA is substantial in North America. Post-operative patients with OSA are at risk for respiratory complications, but about 60% of surgical patients with this condition go undiagnosed. If the presence of sleep apnea is known, non-invasive capnography monitoring can be applied post-operatively to help detect early respiratory compromise during the recovery phase. The STOP-Bang Questionnaire, a validated screening tool to evaluate the risk of OSA, can efficiently be used as part of the pre-surgical evaluation. OBJECTIVES: The aim of this project was to improve safety by averting post-operative respiratory events in patients with obstructive sleep apnea (OSA) through early detection of compromise during recovery from anesthesia. Specific objectives focused on implementing nurse-initiated capnography monitoring of patients with OSA in two post-anesthesia care units and, when indicated, expediently communicating abnormal end-tidal carbon dioxide excursions. METHODS: Strategies and audit data were organized and evaluated using the Joanna Briggs Institute's Getting Research into Practice (GRiP) and Practical Application of Clinical Evidence Systems (PACES) tools. Medical record review was used for the baseline audit and three follow-up compliance audits of evidence-based practice. Multiple teaching methodologies were employed to reach and engage post-anesthesia care unit nurses. Equipment was maintained at the point of care. Nurses' participation in the project was voluntary. RESULTS: There was nearly full compliance with the new practice of initiating capnography, when indicated. Compliance with escalating abnormal capnography results with associated concerning assessment findings was 100%, but the escalation sample size was only two patients. CONCLUSIONS: Patients with known OSA benefited from non-invasive capnography monitoring during recovery from anesthesia because post-anesthesia care unit nurses were empowered to initiate evidence-based technology. Expedient adoption of the new practice was due to comprehensive nurse education, familiarity with a similar capnography monitoring process and the value nurses placed on capnography as another assessment tool to safeguard patients. A larger sample of patients is needed to evaluate compliance with escalating concerning findings to providers. Sustainability will be impacted if the post-anesthesia care unit's standards of care include capnography for patients with OSA.
