A pilot study of preoperative heart rate variability predicting pain during local anesthetic varicose vein surgery.

OBJECTIVE: Local anesthetic endovenous procedures were shown to reduce recovery time, to decrease postoperative pain, and to more quickly return the patient to baseline activities. However, a substantial number of patients experience pain during these procedures. The autonomic nervous system modulates pain perception, and its influence on stress response can be noninvasively quantified using heart rate variability (HRV) indices. The aim of our study was to evaluate whether preoperative baseline HRV can predict intraoperative pain during local anesthetic varicose vein surgery. METHODS: Patients scheduled for radiofrequency ablation were included in the study. They had their electrocardiograms recorded from a single channel of a custom-made amplifier. Each patient preoperatively filled in forms Y-1 and Y-2 of Spielberger's State and Trait Anxiety Inventory, completed the Aberdeen Varicose Vein Questionnaire, and rated anxiety level on a numeric scale. Postoperatively, patients filled in the pain they felt during the procedure on the numeric pain intensity scale. MATLAB software (MathWorks, Natick, Mass) was used to extract R waves and to generate HRV signals, and a mathematical model was created to predict the pain score for each patient. RESULTS: In multivariable analysis, we looked into correlation between reported patient's pain score (rPPS) and Aberdeen Varicose Vein Questionnaire score, preoperative forms Y-1 and Y-2, preoperative anxiety level, and predicted patient's pain (pPPS) score. Multivariable analysis found association only between rPPS and pPPS. The pPPS was significantly correlated with rPPS (R = 0.807; P < .001) with accuracy of prediction of 65.2%, which was calculated from R2 on a linear regression model. CONCLUSIONS: This preliminary study shows that preoperative HRV can accurately predict patients' pain, allowing patients with higher predicted score to have the procedure under general anesthesia.

Sources of Delay in the Acute Limb Ischemia Patient Pathway.

BACKGROUND: Acute limb ischemia (ALI) continues to pose a significant challenge to clinicians and is associated with an unacceptably high rate of morbidity and mortality. Despite its time critical nature, little is known regarding the delays encountered during the patient pathway. The aim of this study was to identify sources of delay in the patient pathway at our institution. METHODS: Sixty-seven cases of ALI of the lower extremities from 66 patients, who had presented to our center between May 2003 and April 2014, were identified for retrospective analysis. Data were retrieved from the patient records, discharge summaries and hospital laboratory, emergency department and radiology databases. RESULTS: Median time from onset of symptom to arrival at our institution was 11.35 hr (interquartile range [IQR] 6.27-72). Median cumulative time taken from arrival to vascular team review was 40 min (22.5-120), to imaging being performed was 4.75 hr (2.42-17.25), and to intervention being performed was 10.2 hr (4-31). There were significantly longer delays to presentation in those transferred from inpatient beds as compared with those transferred from the emergency department of other hospitals (66 hr [10.3-98] vs. 8 hr [5.6-14.9], P = 0.007). In total, 84.6% of patients underwent preoperative arterial imaging. Time taken from arrival to diagnostic arterial imaging was significantly longer in patients presenting out-of-ours (15 hr [6.5-20.75]) as compared with patients presenting in-hours (3.5 hr [2-6.5], P = 0.014) or during the weekend (2 hr [2-3], P = 0.022). Time from presentation to intervention was significantly shorter in patients presenting over the weekend (3.9 hr [2.6-5.1]) as compared with those presenting in-hours (14.2 hr [6.2-29], P = 0.006) and out-of-hours (16 hr [10-33], P = 0.021). Out-of-hours, a significant portion of the delay, was attributable to imaging (median time to imaging 15 hr). CONCLUSIONS: This study demonstrates the systematic nature of delays in the patient pathway from onset of symptoms to treatment. Several factors including time to patient presentation and time to imaging and delays in timely transfer to an appropriate facility contribute to this. Strategies need to be deployed to reduce time to revascularization.