Chloroprocaine Provides Safe, Effective, Short-Acting Spinal Anesthesia Ideal for Ambulatory Surgeries: A Retrospective Review.

BACKGROUND: The ideal local anesthetic for use in ambulatory spinal anesthesia is safe, with minimal adverse effects, and of a duration that does not impede post-anesthesia care unit (PACU) discharge. Since its approval for use in spinal anesthesia in Europe in 2012, chloroprocaine has seen a resurgence. Recent studies have investigated the safety and efficacy of preservative-free chloroprocaine for use in spinal anesthesia, but few provide the incidence of adverse events such as urinary retention and transient neurologic symptoms. QUESTIONS/PURPOSES: We sought to assess the safety of chloroprocaine for spinal anesthesia, including the incidence of adverse events and the duration and quality of its use, in the initial 6 months of its use at our institution. We hypothesized that chloroprocaine would provide effective spinal anesthesia for orthopedic cases of short duration, with a low rate of complications. METHODS: We conducted a retrospective chart review of all patients from June to December 2016 at our institution who had ambulatory knee arthroscopy or foot procedures in which chloroprocaine spinal anesthesia was used. For all 445 charts analyzed, data were collected on anesthesia characteristics, office visits, nursing PACU assessment, and nursing post-operative day 1 follow-up phone calls. RESULTS: The median chloroprocaine dosage was 44 mg (interquartile range [IQR], 40 to 50). The median duration of sensory block was 156 min (IQR, 128 to 189) and of motor block was 148 min (IQR, 123 to 181). Time to ambulation was 186 min (IQR, 158 to 218) and time to meeting of discharge criteria was 218 min (IQR, 189 to 250). The most common adverse events in the PACU were bradycardia and hypotension. No patients had urinary retention or transient neurologic symptoms. CONCLUSIONS: In 6 months of use at our institution, chloroprocaine provided safe and effective spinal anesthesia for short orthopedic procedures, with no incidence of transient neurologic symptoms, neuropraxia, or urinary retention.

Addition of Adductor Canal Block to Periarticular Injection for Total Knee Replacement: A Randomized Trial.

BACKGROUND: Periarticular injection is a popular method to control postoperative pain after total knee replacement. An adductor canal block is a sensory block that can also help to alleviate pain after total knee replacement. We hypothesized that the combination of adductor canal block and periarticular injection would allow patients to reach discharge criteria 0.5 day faster than with periarticular injection alone. METHODS: This prospective trial enrolled 56 patients to receive a periarticular injection and 55 patients to receive an adductor canal block and periarticular injection. Both groups received intraoperative neuraxial anesthesia and multiple different types of pharmaceutical analgesics. The primary outcome was time to reach discharge criteria. Secondary outcomes, collected on postoperative days 1 and 2, included numeric rating scale pain scores, the PAIN OUT questionnaire, opioid consumption, and opioid-related side effects. RESULTS: There was no difference in time to reach discharge criteria between the groups with and without an adductor canal block. The Wilcoxon-Mann-Whitney odds ratio was 0.87 (95% confidence interval [CI], 0.55 to 1.33; p = 0.518). The median time to achieve discharge criteria (and interquartile range) was 25.8 hours (23.4 hours, 44.3 hours) in the adductor canal block and periarticular injection group compared with 26.4 hours (22.9 hours, 46.2 hours) in the periarticular injection group. Patients who received an adductor canal block and periarticular injection reported lower worst pain (difference in means, -1.4 [99% CI, -2.7 to 0]; adjusted p = 0.041) and more pain relief (difference in means, 12% [99% CI, 0% to 24%]; adjusted p = 0.048) at 24 hours after anesthesia. There was no difference in any other secondary outcome measure (e.g., opioid consumption, opioid-related side effects, numeric rating scale pain scores). CONCLUSIONS: The time to meet the discharge criteria was not significantly different between the groups. In the adductor canal block and periarticular injection group, the patients had lower worst pain and greater pain relief at 24 hours after anesthesia. No difference was noted in any other secondary outcome measure (e.g., opioid consumption, opioid-related side effects, numeric rating scale pain scores). LEVEL OF EVIDENCE: Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

Imagined Examples of Painful Experiences Provided by Chronic Low Back Pain Patients and Attributed a Pain Numerical Rating Score.

OBJECTIVE: The pain numerical rating scale (NRS) is widely used in pain research and clinical settings to represent pain intensity. For an individual with chronic pain, NRS reporting requires representation of a complex subjective state as a numeral. To evaluate the process of NRS reporting, this study examined the relationship between reported pain NRS levels and imagined painful events reported by study subjects. DESIGN: A total of 149 subjects with chronic low back pain characterized by the NIH Research Task Force Recommended Minimal Dataset reported current pain NRS and provided imagined examples of painful experiences also attributing to these an NRS. We present a quantitative and qualitative analysis of the 797 pain examples provided by the study subjects. RESULTS: Study subjects tended to be able to imagine both highly painful 10/10 events and non-painful events with relative agreement across subjects. While NRS for the pain examples tended to increase with example severity, for many types of examples there was wide dispersion around the mean pain level. Examination of pain examples indicated unexpected relationships between current pain and the intensity and nature of the imagined painful events. CONCLUSIONS: Our results indicate that the pain NRS does not provide a reliably interpretable assessment of current physical pain intensity for an individual with chronic pain at a specific moment.