Accelerated Idioventricular Rhythm Following Intraoral Local Anesthetic Injection During General Anesthesia

Some anesthetic agents or adjunct medications administered during general anesthesia can cause an accelerated idioventricular rhythm (AIVR), which is associated with higher vagal tone and lower sympathetic activity. We encountered AIVR induced by vagal response to injection-related pain following local anesthetic infiltration into the oral mucosa during general anesthesia. A 48-year-old woman underwent extraction of a residual tooth root from the left maxillary sinus under general anesthesia. Routine preoperative electrocardiogram (ECG) was otherwise normal. Eight milliliters of 1% lidocaine (80 mg) with 1:100,000 epinephrine (80 μg) was infiltrated around the left maxillary molars over 20 seconds using a 23-gauge needle and firm pressure. Widened QRS complexes consistent with AIVR were observed for ∼60 seconds, followed by an atrioventricular junctional rhythm and the return of normal sinus rhythm. A cardiology consultation and 12-lead ECG in the operating room produced no additional concerns, so the operation continued with no complications. AIVR was presumably caused by activation of the trigeminocardiac reflex triggered by intense pain following rapid local anesthetic infiltration with a large gauge needle and firm pressure. Administration of local anesthetic should be performed cautiously when using a large gauge needle and avoid excessive pressure.

Does the addition of iPACK to adductor canal block in the presence or absence of periarticular local anesthetic infiltration improve analgesic and functional outcomes following total knee arthroplasty? A systematic review and meta-analysis

BackgroundWhen combined with adductor canal block (ACB), local anesthetic infiltration between popliteal artery and capsule of knee (iPACK) is purported to improve pain following total knee arthroplasty (TKA). However, the analgesic benefits of adding iPACK to ACB in the setting of surgeon-administered periarticular local infiltration analgesia (LIA) are unclear.ObjectivesTo evaluate the analgesic benefits of adding iPACK to ACB, compared with ACB alone, in the setting of LIA following TKA.Evidence reviewWe conducted a meta-analysis of randomized trials comparing the effects of adding iPACK block to ACB versus ACB alone on pain severity at 6 hours postoperatively in adult patients undergoing TKA. We a priori planned to stratify analysis for use of LIA. Opioid consumption at 24 hours, functional recovery, and iPACK-related complications were secondary outcomes.FindingsFourteen trials (1044 patients) were analyzed. For the primary outcome comparison in the presence of LIA (four trials, 273 patients), adding iPACK to ACB did not improve postoperative pain at 6 hours. However, in the absence of LIA (eight trials, 631 patients), adding iPACK to ACB reduced pain by a weighted mean difference (WMD) (95% CI) of −1.33 cm (−1.57 to –1.09) (p<0.00001). For the secondary outcome comparisons in the presence of LIA, adding iPACK to ACB did not improve postoperative pain at all other time points, opioid consumption or functional recovery. In contrast, in the absence of LIA, adding iPACK to ACB reduced pain at 12 hours, and 24 hours by a WMD (95% CI) of −0.98 (−1.79 to –0.17) (p=0.02) and −0.69 (−1.18 to –0.20) (p=0.006), respectively, when compared with ACB alone, but did not reduce opioid consumption. Functional recovery was also improved by a log(odds ratio) (95% CI) of 1.28 (0.45 to 2.11) (p=0.003). No iPACK-related complications were reported.ConclusionAdding iPACK to ACB in the setting of periarticular LIA does not improve analgesic outcomes following TKA. In the absence of LIA, adding iPACK to ACB reduces pain up to 24 hours and enhances functional recovery. Our findings do not support the addition of iPACK to ACB when LIA is routinely administered.