The purpose of this study is to determine whether baroreceptor sensitivity (the ability of your body to change your heart rate and/or blood pressure in response to a situation) has any effect on how likely you are to suffer certain events after heart or lung surgery. The postoperative events that the investigators will be studying are pain after surgery, atrial fibrillation (an irregular heart rhythm), and cognitive dysfunction (a decline in mental abilities).

The purpose of this study is to determine if preoperative baroreceptor sensitivity (BRS) correlates with major outcomes after cardiac and thoracic surgery, including acute and chronic pain, atrial arrhythmias, and cognitive function. To test this hypothesis, approximately 95 patients will be enrolled, and spontaneous baroreceptor sensitivity will be measured prior to surgery as well as immediately postoperatively. Outcomes will include acute pain using the numeric rating scale, Brief Pain Inventory, and Gracely Box Scale administered preoperatively, on postoperative days 1 and 2 and by phone at 6-weeks postoperatively. Chronic pain will be assessed at 6-month follow-up visit via hyperalgesia testing using Von Frey filaments. Postoperative atrial arrhythmias will be assessed by review of postoperative telemetry, the electronic medical record, and ECG performed prior to discharge. Finally, cognitive function will be assess via Mini-Mental State examination administered preoperative and at the 6-month follow-up visit. Association between BRS and the outcomes of interest will be tested with regression models adjusted for appropriate covariates. Significance threshold alpha will be adjusted for the number of statistical tests using the Bonferroni correction. Our hypothesis is that patients with impaired preoperative BRS will have an increased incidence of acute and chronic postoperative pain, atrial fibrillation, and cognitive decline after surgery.

Inclusion Criteria:

• >= 18 years of age
• Undergoing cardiac (coronary artery bypass grafting [CABG], CABG + valve, or valve only) or thoracic (video-assisted thoracoscopic [VATS] approach to lobectomy) surgery

Exclusion Criteria:

• Any preexisting pain condition (defined as pain of >=3 months duration prior to enrollment)
• Pain at the time of enrollment interview
• Need for preoperative analgesics
• Preexisting chronic or paroxysmal atrial fibrillation
• Preexisting atrial or ventricular arrhythmia
• Need for preoperative anti-arrhythmic medication
• History of symptomatic cerebrovascular disease (e.g., prior stroke) with residual deficits
• Alcoholism (>2 drinks/day)
• Psychiatric illness (any clinical diagnosis requiring therapy)
• Drug abuse (any illicit drug use in the preceding 3 months before surgery)
• Hepatic insufficiency (liver function tests > 1.5 times the upper limit of normal)
• Severe pulmonary insufficiency (home oxygen)
• Renal failure (serum creatinine >2.0 mg/dL)
• Non-English speaking
• Unable to read
• Participants who score <24 on baseline Mini Mental State examination

All patients presenting for cardiac and thoracic surgery at Duke University Hospital, a quaternary referral center