How long to wait after local infiltration anaesthesia: systematic review.

BACKGROUND: Conflicting evidence exists regarding the optimal waiting time for stable analgesic and vasoconstrictive effects after local infiltration of lidocaine with epinephrine. An objective review is needed to dispel surgical dogma. METHODS: This systematic review (PROSPERO ID: CRD42022362414) included RCTs and prospective cohort studies. Primary outcomes were (1) onset of analgesia and (2) onset of stable hypoperfusion, assessed directly, or measured indirectly using perfusion imaging. Other data extracted include waiting strategies, means of outcome assessment, anaesthetic concentrations, volume/endpoint of infiltration, and injection sites. Methodological quality was evaluated using the Cochrane risk-of-bias tool for randomized trials. Articles describing waiting strategies were critically appraised by the Joanna Briggs Institute tools. RESULTS: Twenty-four articles were analysed, comprising 1013 participants. Ten investigated analgesia onset. Their pooled mean was 2.1 min (range 0.4-9.0 min). This varied with anatomic site and targeted nerve diameter. Fourteen articles investigated onset of stable hypoperfusion. Four observed bleeding intraoperatively, finding the minimum time to hypoperfusion at 7.0 min in the eyelid skin and 25.0 min in the upper limb. The ten remaining studies used perfusion imaging, reporting a wide range of results (0.0-30.0 min) due to differences in anatomic sites and depth, resolution and artefacts. Studies using near-infrared reflectance spectroscopy and hyperspectral imaging correlated with clinical observations. Thirteen articles discussed waiting strategies, seven relating to large-volume tumescent local infiltration anaesthesia. Different waiting strategies exist for emergency, arthroscopic and cosmetic surgeries, according to the degree of hypoperfusion required. In tumescent liposuction, waiting 10.0-60.0 min is the norm. CONCLUSION: Current literature suggests that around 2 min are required for most patients to achieve complete analgesia in all sites and with all anaesthesia concentrations. Waiting around 7 min in eyelids and at least 25 min in other regions results in optimal hypoperfusion. The strategies discussed inform decisions of when and how long to wait.

Pain Relief Durations of Different Concentrations of Lidocaine in Wide Awake Hand Surgery: A Prospective Randomised Clinical Trial.

OBJECTIVE: This study aims to determine the minimal concentration of lidocaine to provide adequate analgesia in wide awake local anaesthesia no tourniquet (WALANT) hand surgeries comparing 3 dilutions of tumescent lidocaine with epinephrine solution. STUDY DESIGN: A randomised control trial. Place and Duration of the Study: The study was held at the Plastic Surgery Department of Mayo Hospital, Lahore, from September 2020 to March 2021. METHODOLOGY: Inclusion criteria were post-traumatic hand contractures and tendon and nerve injuries. The patients were randomised to 3 groups of 30 each: Group A (0.1% lidocaine), Group B (0.2% lidocaine), and Group C (0.3% lidocaine). The dilution of adrenaline also remained constant at 1:200,000. Pain was measured using the Visual Analogue Scale. The three groups were compared for demographics and the total duration of analgesia in minutes. RESULTS: All groups showed adequate pain relief during surgery with no cases requiring conversion to general anaesthesia. The highest total duration of analgesia was seen in the 0.3% group (805.3±195.2 minutes), followed by the 0.2% group (500.4±87.2 minutes) and 0.1% group (381.3±31.6 minutes) (p<0.05). No patient developed any signs of lidocaine toxicity. A low Lidocaine concentration of 0.1% was effective in providing analgesia during surgery though increasing the lidocaine concentration to 0.3% would result in greater post-operative analgesic time without increasing toxicity. CONCLUSION: Adequate analgesia was recorded with all 3 lidocaine concentrations. The greatest pain-free duration was however observed in the  0.3% lidocaine group. KEY WORDS: Wide awake local anaesthesia no tourniquet (WALANT), Lidocaine concentrations, Hand surgery, Analgesia, Adverse effects.

Effect of Time Interval Between Tumescent Local Anesthesia Infiltration and Start of Surgery on Operative Field Visibility in Hand Surgery Without Tourniquet.

PURPOSE: To determine the optimal time interval between tumescent local anesthesia infiltration and the start of hand surgery without a tourniquet for improved operative field visibility. METHODS: Patients aged 16 to 60 years who needed contracture release and tendon repair in the hand were enrolled from the outpatient clinic. Patients were randomized to 10-, 15-, or 25-minute intervals between tumescent anesthetic solution infiltration (0.18% lidocaine and 1:221,000 epinephrine) and the start of surgery. The end point of tumescence anesthetic infiltration was pale and firm skin. The surgical team was blinded to the time of anesthetic infiltration. At the completion of the procedure, the surgeon and the first assistant rated the operative field visibility as excellent, fair, or poor. We used logistic regression models without and with adjustment for confounding variables. RESULTS: Of the 75 patients enrolled in the study, 59 (79%) were males, 7 were randomized to 10-minute time intervals (further randomization was stopped after interim analysis found consistently poor operative field visibility), and 34 were randomized to the each of the 15- and 25-minute groups. Patients who were randomized to the 25-minute delay group had 29 times higher odds of having an excellent operative visual field than those randomized to the 15-minute delay group. After adjusting for age, sex, amount of tumescent solution infiltration, and duration of operation, the odds ratio remained highly significant. CONCLUSIONS: We found that an interval of 25 minutes provides vastly superior operative field visibility; 10-minute delay had the poorest results. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic I.

Comparison of postoperative pain relief by intercostal block between pre-rib harvest and post-rib harvest groups.

OBJECTIVE: To compare intercostal nerve block before and after rib harvest in terms of mean postoperative pain score and mean postoperative tramadol usage. STUDY DESIGN: Randomized controlled trial. PLACE AND DURATION OF STUDY: Department of Plastic Surgery, Mayo Hospital, KEMU, Lahore, from January 2011 to July 2012. METHODOLOGY: Patients (n = 120) of either gender with ASA class-I and II requiring autogenous costal cartilage graft were inducted. Patients having history of local anaesthetic hypersensitivity and age < 15 years or > 60 years were excluded. Subjects were randomly assigned to pre-rib harvest (group-1) and post-rib harvest (group-2). Local anaesthetic mixture was prepared by adding 10 milliliters 2% lidocaine to 10 milliliters 0.5% bupivacaine to obtain a total 20 ml solution. Group-1 received local anaesthetic infiltration along the proposed incision lines and intercostals block before the rib harvest. Group-2 received the infiltration and block after rib harvest. Postoperative consumption of tramadol and pain scores were measured at 6 and 12 hours postoperatively using VAS. RESULTS: Mean age was 31.43 ± 10.78 years. The mean pain scores at 6 hours postoperatively were 1.033 ± 0.609 and 2.4667 ± 0.812 in pre-rib harvest and post-rib harvest groups respectively (p < 0.0001). The mean pain scores at 12 hours postoperatively were 1.45 ± 0.565 and 3.65 ± 0.633 in pre-rib harvest and post-rib harvest groups respectively (p < 0.0001). The mean tramadol used postoperatively in first 24 hours was 169 ± 29.24 mg and 255 ± 17.70 mg in prerib harvest and post-rib harvest groups respectively (p < 0.0001). CONCLUSION: Intercostal block administered before rib harvest as preemptive strategy result in decreased postoperative pain scores and narcotic use.