A single center descriptive study of local anesthetic dose in knee arthroplasty: Was there evidence of local anesthetic systemic toxicity?

STUDY OBJECTIVE: Describe dosing of local anesthetic when both a periarticular injection (PAI) and peripheral nerve block (PNB) are utilized for knee arthroplasty analgesia, and compare the dosing of local to suggested maximum dosing, and look for evidence of local anesthetic systemic toxicity (LAST). DESIGN: A single center retrospective cohort study between May 2018 and November 2022. SETTING: A major academic hospital. PATIENTS: Patients who had both a PAI and PNB while undergoing primary, revision, total, partial, unilateral, or bilateral knee arthroplasty. INTERVENTIONS: None. MEASUREMENTS: Calculate the dose of local anesthetic given via PAI, PNB, and both routes combined as based on lean body weight and compare that to the suggested maximum dosing. Look for medications, clinical interventions, and critical event notes suggestive of a LAST event. MAIN RESULTS: There were 4527 knee arthroplasties where both a PAI and PNB were performed during the study period. When combining PAI and PNB doses, >75% of patients received more than the suggested maximum dose of 3 mg/kg lean body weight. The median local anesthetic dosing over the study period, 4.4 mg/kg (IQR 3.5,5.9), was 147% of the suggested maximum dose (IQR 117,197). There was no conclusive evidence of LAST among any of the patients in the study. CONCLUSIONS: Over the course of our study, we had 4527 knee arthroplasties with a median PAI and PNB local anesthetic dose that was 147% of the suggested maximum without any clear clinical evidence of a LAST event.

Re-evaluation of the methodology for estimating the US specialty physician workforce.

Increasing pursuit of subspecialized training has quietly revolutionized physician training, but the potential impact on physician workforce estimates has not previously been recognized. The Physicians Specialty Data Reports of the Association of American Medical Colleges, derived from specialty designations in the American Medical Association (AMA) Physician Professional Data (PPD), are the reference source for US physician workforce estimates; by 2020, the report for pathologists was an undercount of 39% when compared with the PPD. Most of the difference was due to the omission of pathology subspecialty designations. The rest resulted from reliance on only the first of the AMA PPD's 2 specialty data fields. Placement of specialty designation in these 2 fields is sensitive to sequence of training and is thus affected by multiple or intercalated (between years of residency training) fellowships. Both these phenomena have become progressively more common and are not unique to pathology. Our findings demonstrate the need to update definitions and methodology underlying estimates of the US physician workforce for pathology and suggest a like need in other specialties affected by similar trends.

Processing difficulty while reading words with neighbors is not due to increased foveal load: Evidence from eye movements.

Words with high orthographic relatedness are termed "word neighbors" (angle/angel; birch/birth). Activation-based models of word recognition assume that lateral inhibition occurs between words and their activated neighbors. However, studies of eye movements during reading have not found inhibitory effects in early measures assumed to reflect lexical access (e.g., gaze duration). Instead, inhibition in eye-movement studies has been found in later measures of processing (e.g., total time, regressions in). We conducted an eye-movement boundary change study (Rayner, Cognitive Psychology, 7(1), 65-81, 1975) that manipulated the parafoveal preview of the word following the neighbor word (word N+1). In this way, we explored whether the late inhibitory effects seen with transposed letter words and words with higher-frequency neighbors result from reduced parafoveal preview due to increased foveal load and/or interference during late stages of lexical processing (the L2 stage within the E-Z Reader framework). For word N+1, while there were clear preview effects, there was not an effect of the neighborhood status of word N, nor a significant interaction. This suggests that the late inhibitory effects of earlier eye-movement studies are driven by misidentification of neighbor words rather than being due to increased foveal load.