Comparison of programmed intermittent bolus infusion and continuous infusion for postoperative patient-controlled analgesia with thoracic paravertebral block catheter: a randomized, double-blind, controlled trial

Local Anesthetic Systemic Toxicity in Cardiac Surgery Patient with Erector Spinae Plane Catheter: A Case Report

Regional anesthesia nerve blocks are increasingly used for patients undergoing cardiac surgery as part of multimodal pain management. Though rare, local anesthetic systemic toxicity (LAST) is a severe complication that requires vigilant monitoring. We present a case of a postcardiac surgery patient who developed LAST multiple days after surgery from lidocaine via an erector spinae plane catheter. This episode was determined to be a result of impaired lidocaine metabolism from liver shock caused by worsening pulmonary hypertension. Even under continuous monitoring, patients with cardiac or liver dysfunction are at increased risk of complications from local anesthetics.

Effect of Intermittent Thoracic Paravertebral Block on Postoperative Nausea and Vomiting Following Thoracoscopic Radical Resection of the Lung Cancer: A Prospective Randomized Trial

Purpose

To explore the benefits of ultrasound-guided intermittent thoracic paravertebral block (TPVB) combined with intravenous analgesia (PCIA) in alleviating postoperative nausea and vomiting (PONV) during video-assisted thoracic surgery (VATS).

Patients and Methods

120 patients with lung carcinoma undergoing VATS were included and divided into three groups: group S (single TPVB+PCIA), group I (intermittent TPVB+PCIA), and group P (PCIA). The patients' NRS scores, postoperative hydromorphone hydrochloride consumption, and intramuscular injection of bucinnazine hydrochloride were recorded. The incidence of PONV and complications were documented.

Results

Compared with the group P, both group I and group S had significantly lower static NRS scores from 1-48 hours after the operation (P <0.05), and the dynamic NRS score of group I at the 1-48 hours after the operation were significantly decreased (P <0.05). Compared with the group P, the proportion of patients with PONV in group I was significantly lower (P <0.05), while there was no significant difference in group S. Moreover, the hospitalization period of patients in group I was significantly reduced compared with the other two groups (P <0.01), and the patient satisfaction was significantly increased compared with the group P (P <0.05).

Conclusion

Intermittent TPVB combined with PCIA can reduce the postoperative pain and the occurrence of PONV.

Local anesthetic dosing and toxicity of adult truncal catheters: a narrative review of published practice

BACKGROUND/IMPORTANCE

Anesthesiologists frequently use truncal catheters for postoperative pain control but with limited characterization of dosing and toxicity.

OBJECTIVE

We reviewed the published literature to characterize local anesthetic dosing and toxicity of paravertebral and transversus abdominis plane catheters in adults.

EVIDENCE REVIEW

We searched the literature for bupivacaine or ropivacaine infusions in the paravertebral or transversus abdominis space in humans dosed for 24 hours. We evaluated bolus dosing, infusion dosing and cumulative 24-hour dosing in adults. We also identified cases of local anesthetic systemic toxicity and toxic blood levels.

FINDINGS

Following screening, we extracted data from 121 and 108 papers for ropivacaine and bupivacaine respectively with a total of 6802 patients. For ropivacaine and bupivacaine, respectively, bolus dose was 1.4 mg/kg (95% CI 0.4 to 3.0, n=2978) and 1.0 mg/kg (95% CI 0.18 to 2.1, n=2724); infusion dose was 0.26 mg/kg/hour (95% CI 0.06 to 0.63, n=3579) and 0.2 mg/kg/hour (95% CI 0.06 to 0.5, n=3199); 24-hour dose was 7.75 mg/kg (95% CI 2.1 to 15.7, n=3579) and 6.0 mg/kg (95% CI 2.1 to 13.6, n=3223). Twenty-four hour doses exceeded the package insert recommended upper limit in 28% (range: 17%-40% based on maximum and minimum patient weights) of ropivacaine infusions and 51% (range: 45%-71%) of bupivacaine infusions. Toxicity occurred in 30 patients and was associated with high 24-hour dose, bilateral catheters, cardiac surgery, cytochrome P-450 inhibitors and hypoalbuminemia.

CONCLUSION

Practitioners frequently administer ropivacaine and bupivacaine above the package insert limits, at doses associated with toxicity. Patient safety would benefit from more specific recommendations to limit excessive dose and risk of toxicity.

Comparing Continuous and Intermittent Infusion Effects on Serratus Anterior Plane Blocks in Video-Assisted Thoracoscopic Surgery: A Randomized Clinical Trial

Objective

The programmed intermittent bolus infusion (PIBI) of local anesthetic produces wider sensory blockade and better analgesia than continuous infusion (CI). We designed this trial to compare the effects of these two different infusion methods combined with Serratus Anterior Plane Blocks (cSAPBs) on postoperative pain relief in patients undergoing video-assisted thoracoscopic surgery.

Methods

We randomly allocated 66 patients under going elective video-assisted thoracoscopic unilateral lung resection surgery to two groups (PIBI group and CI group, n=33 per group). After the surgical operation, the patients received ultrasound-guided ipsilateral SAPB, we randomized them to receive either automated intermittent boluses or continuous infusion of 0.3% ropivacaine. Tramadol consumption during the 48 hours following surgery was the primary outcome. Secondary outcomes included cumulative tramadol consumption during the first 24-h and the second 24-h periods after surgery, pain scores, patient satisfaction, blocked dermatomes, and adverse events.

Results

During 48h, tramadol consumption in the PIBI group was significantly lower than in the CI group (190 mg [125, 305] vs 220 mg [170, 480], p= 0.034). As compared to the CI group, the PIBI group consumed less tramadol during the first 24 hours (145 mg [87.5, 210] vs 190 mg [140, 400], p=0.012). The dermatomes anesthetized to the pinprick and cold test were significantly more abundant in the PIBI group than in the CI group (3 [3,4] vs. 5 [4,5], p<0.001). Both groups had similar VAS scores at rest and when moving (p>0.05). Additionally, the PIBI group showed greater patient satisfaction. Both groups experienced similar adverse events (p>0.05).

Conclusion

Compared with CI, PIBI administration regimen (0.3% ropivacaine 5 mL/h) for cSAPBs resulted in lower tramadol consumption, superior analgesia during the initial 12 h after the operation, and higher patient satisfaction. PIBI combined with cSAPBs was a better choice for postoperative analgesia in patients undergoing video-assisted thoracoscopic surgery.

Rhomboid intercostal block or thoracic paravertebral block for postoperative recovery quality after video-assisted thoracic surgery: A prospective, non-inferiority, randomised controlled trial

BACKGROUND

The analgesic characteristics of rhomboid intercostal block (RIB) remain unclear. Before it can be fully recommended, we compared the recovery quality and analgesic effects of RIB and thoracic paravertebral block (TPVB) for video-assisted thoracoscopic surgery (VATS).

OBJECTIVE

The current study aimed to investigate whether there is a difference in postoperative recovery quality between TPVB and RIB.

DESIGN

A prospective, non-inferiority, randomised controlled trial.

SETTING

Affiliated Hospital of Jiaxing University in China from March 2021 to August 2022.

PATIENTS

Eighty patients aged 18 to 80 years, with ASA physical status I to III, and scheduled for elective VATS were enrolled in the trial.

INTERVENTION

Ultrasound-guided TPVB or RIB was performed with 20 ml 0.375% ropivacaine.

MAIN OUTCOME MEASURES

The primary outcome of the study was the mean difference of quality of recovery-40 scores 24 h postoperatively. The non-inferiority margin was defined as 6.3. Numeric rating scores (NRS) for pain at 0.5, 1, 3, 6, 12, 24 and 48 h postoperatively in all patients were also recorded.

RESULTS

A total of 75 participants completed the study. The mean difference of quality of recovery-40 scores 24 h postoperatively was -1.6 (95% CI, -4.5 to 1.3), demonstrating the non-inferiority of RIB to TPVB. There was no significant difference between the two groups in the area under the curve for pain NRS over time, at rest and on movement, at 6, 12, 24 and 48 h postoperatively (all P  > 0.05), except for the area under the curve pain NRS over time on movement at 48 h postoperatively ( P  = 0.046). There were no statistical differences between the two groups in the postoperative sufentanil use at 0 to 24 h or 24 to 48 h (all P  > 0.05).

CONCLUSION

Our study suggests that RIB was non-inferior to TPVB for the quality of recovery, with almost the same postoperative analgesic effect as TPVB after VATS.

CLINICAL TRIAL REGISTRATION

chictr.org.cn: ChiCTR2100043841.

The effects of intermittent bolus paravertebral block on analgesia and recovery in open hepatectomy: a randomized, double-blinded, controlled study

BACKGROUND

We aimed to investigate the effects of intermittent bolus paravertebral block on analgesia and recovery in open hepatectomy.

METHODS

Eighty 18-70 years old, American Society of Anesthesiologists level I-III patients scheduled for hepatectomy with a J-shaped subcostal incision were enrolled and randomized to receive either intermittent bolus paravertebral ropivacaine (0.5% loading, 0.2% infusion) or 0.9% saline infusion at 1:1 ratio (25 ml loading before surgery, 0.125 ml/kg/h bolus for postoperative 48 h). The primary outcome was set as postoperative 48 h cumulative intravenous morphine consumption recorded by a patient-controlled analgesic pump.

RESULTS

Thirty-eight patients in each group completed the study. The cumulative morphine consumptions were lower in the paravertebral block than control group at postoperative 24 (difference -10.5 mg, 95%CI -16 mg to -6 mg, P < 0.001) and 48 (difference -12 mg, 95%CI -19.5 mg to -5 mg, P = 0.001) hours. The pain numerical rating scales at rest were lower in the paravertebral block than control group at postoperative 4 h (difference -2, 95%CI -3 to -1, P < 0.001). The active pain numerical rating scales were lower in the paravertebral block than control group at postoperative 12 h (difference -1, 95%CI -2 to 0, P = 0.005). Three months postoperatively, the paravertebral block group had lower rates of hypoesthesia (OR 0.28, 95%CI 0.11 to 0.75, P = 0.009) and numbness (OR 0.26, 95%CI 0.07 to 0.88, P = 0.024) than the control group.

CONCLUSIONS

Intermittent bolus paravertebral block provided an opioid-sparing effect and enhanced recovery both in hospital and after discharge in patients undergoing hepatectomy.

TRIAL REGISTRATION

clinicaltrials.gov (NCT04304274), date: 11/03/2020.

Erector spinae plane block for postoperative analgesia in robotically-assisted coronary artery bypass surgery: Results of a randomized placebo-controlled trial

STUDY OBJECTIVE

To investigate if an erector spinae plane (ESP) block decreases postoperative opioid consumption, pain and postoperative nausea and vomiting in patients undergoing robotically-assisted minimally invasive direct coronary artery bypass surgery (RAMIDCAB).

DESIGN

A single-center, double-blind, prospective, randomized, placebo-controlled trial.

SETTING

Postoperative period; operating room, post-anesthesia care unit (PACU) and hospital ward in a university hospital.

PATIENTS

Sixty-four patients undergoing RAMIDCAB surgery via left-sided mini-thoracotomy and enrolled in the institutional enhanced recovery after cardiac surgery program.

INTERVENTIONS

At the end of surgery, patients received an ESP catheter at vertebra T5 under ultrasound guidance and were randomized to the administration of either ropivacaine 0.5% (loading dose of 30 ml and three additional doses of 20 ml each, interspersed with a 6 h interval) or normal saline 0.9% (with an identical administration scheme). In addition, patients received multimodal analgesia including acetaminophen, dexamethasone and patient-controlled analgesia with morphine. Following the final ESP bolus and before catheter removal, the position of the catheter was re-evaluated by ultrasound. Patients, investigators and medical personnel were blinded for the group allocation during the entire trial.

MEASUREMENTS

Primary outcome was cumulative morphine consumption during the first 24 h after extubation. Secondary outcomes included location and severity of pain, presence/extent of sensory block, duration of postoperative ventilation and hospital length of stay. Safety outcomes comprised the incidence of adverse events.

MAIN RESULTS

Median (IQR) 24-h morphine consumption was not different between the intervention- and control-groups, 67 mg (35-84) versus 71 mg (52-90) (p = 0.25), respectively. Likewise, no differences were detected in secondary and safety endpoints.

CONCLUSIONS

Following RAMIDCAB surgery, adding an ESP block to a standard multimodal analgesia regimen did not reduce opioid consumption and pain scores.

Parasternal intercostal plane block catheters for cardiac surgery: a retrospective, propensity weighted, cohort study

Aim: Anesthesia for cardiac surgery has evolved toward fast-track recovery strategies incorporating non opioid analgesics and regional anesthesia. Materials & methods: This retrospective cohort study compared opioid consumption, pain scores and length of stay in patients who underwent cardiac surgery via median sternotomy and did or did not receive preoperative parasternal intercostal plane block catheters with postoperative ropivacaine infusions. Results: Postoperative opioid consumption and postoperative pain scores did not differ. Blocks were associated with decreased intraoperative opioids and reduced length of stay in the intensive care unit and hospital. Conclusion: Parasternal intercostal plane block catheters were not associated with decreased postoperative opioid consumption or pain scores, but were associated with reduced intraoperative opioids and length of stay.

Efficacy of erector spinae plane block for minimally invasive mitral valve surgery: Results of a double-blind, prospective randomized placebo-controlled trial

STUDY OBJECTIVE

To investigate if an erector spinae plane (ESP) block decreases postoperative opioid consumption, pain and postoperative nausea and vomiting in patients undergoing minimally invasive mitral valve surgery (MIMVS).

DESIGN

A single-center, double-blind, prospective, randomized, placebo-controlled trial.

SETTING

Postoperative period; operating room, post-anesthesia care unit (PACU) and hospital ward in a university hospital.

PATIENTS

Seventy-two patients undergoing video-assisted thoracoscopic MIMVS via right-sided mini-thoracotomy and enrolled in the institutional enhanced recovery after cardiac surgery program.

INTERVENTIONS

At the end of surgery, all patients received an ESP catheter at vertebra T5 under ultrasound guidance and were randomized to the administration of either ropivacaine 0.5% (loading of dose 30 ml and three additional doses of 20 ml with a 6 h interval) or normal saline 0.9% (with an identical administration scheme). In addition, patients received multimodal postoperative analgesia including dexamethasone, acetaminophen and patient-controlled intravenous analgesia with morphine. Following the final ESP bolus and before catheter removal, the position of the catheter was re-evaluated by ultrasound. Patients, investigators and medical personnel were blinded for the group allocation during the entire trial.

MEASUREMENTS

Primary outcome was cumulative morphine consumption during the first 24 h after extubation. Secondary outcomes included severity of pain, presence/extent of sensory block, duration of postoperative ventilation and hospital length of stay. Safety outcomes comprised the incidence of adverse events.

MAIN RESULTS

Median (IQR) 24-h morphine consumption was not different between the intervention- and control-group, 41 mg (30-55) versus 37 mg (29-50) (p = 0.70), respectively. Likewise, no differences were detected for secondary and safety endpoints.

CONCLUSIONS

Following MIMVS, adding an ESP block to a standard multimodal analgesia regimen did not reduce opioid consumption and pain scores.

High Dosage of Patient-Controlled Epidural Analgesia (PCEA) with Low Background Infusion during Labor: A Randomized Controlled Trial

BACKGROUND

Patient-controlled epidural analgesia (PCEA) is well documented; however, it is unclear whether a high dosage of PCEA with a low dosage of background infusion during labor can be a safe and effective application.

METHODS

Group LH was administered a continuous infusion (CI) of 0.084 mL/kg/h with PCEA of 5 mL every 40 min. Group HL was given a CI of 0.028 mL/kg/h and PCEA of 10 mL every 40 min; Group HH was given a CI of 0.084 mL/kg/h and PCEA of 10 mL every 40 min. The primary outcomes were VAS pain score, the number of supplemental boluses, incidence of pain outbreaks, drug dose for pain outbreaks, PCA times, effective PCA times, anesthetic consumption, duration of analgesia, duration of labor and delivery outcome. Secondary outcomes included adverse reactions such as itching, nausea and vomiting during analgesia and neonatal Apgar scores 1 min and 5 min after birth.

RESULTS

A total of 180 patients, 60 in each group were randomly assigned to one of three groups included group LH, group HL or group HH. The VAS scores were obviously decreased in HL group and HH group in comparison with LL group at 2 h after analgesia and the time point of full cervical dilation and delivery of baby. The time for third stage of labor in HH group was increased compared with LH group and HL group. Incidence of pain outbreaks in LH group was obviously increased compared with HL and HH group. The effective PCA times in HL group and HH group were remarkably reduced compared with those in LH group.

CONCLUSIONS

High dose of PCEA with a low background infusion can reduce effective PCA times, incidence of outbreak pain and the total amount of anesthetics without diminishing analgesia effects. However, high dose of PCEA with a high background infusion can enhance analgesia effect but increase the third stage of labor, instrumental delivery ratio and the total amount of anesthetics.

Postoperative Pain in Patients Undergoing Cancer Surgery and Intravenous Patient-Controlled Analgesia Use: The First and Second 24 h Experiences

INTRODUCTION

Postoperative cancer pain imposes severe physical and psychological problems. We aimed to investigate the pain experiences of patients with cancer after surgery, analyze the impact of infusion volume by patient-controlled analgesia (PCA), and explore the variations between day 1 and day 2.

METHODS

Data were retrospectively extracted from a large health data platform. Descriptive statistics were presented for the demographic and clinical profiles of patients. Multiple logistic regression analyses were performed to evaluate associations between intensity of pain and PCA use after adjustment for risk factors.

RESULTS

Among 11,383 patients with cancer, the incidence of pain (moderate to severe pain) was 93.3% (18.3%) at the first 24 h after operation, while the respect values decreased to 91.1% and 9.5% at the second 24 h. Further, female patients consistently experienced higher risk of pain over the whole 48 h postoperatively. Surgical sites were related to pain risk, with the highest risk among the respiratory system (OR 2.077, 95% CI 1.392-3.100). High doses of continuous volume (OR 2.453, 95% CI 1.742-3.456) and total volume (OR 2.830, 95% CI 2.037-3.934) of infusions were related to 1-3-fold elevated pain risk. Additionally, the observed associations were mostly repeated and could be up to over 10 times when pain was evaluated with number of PCA pump compressions instead of Numerical Rating Scale (NRS).

CONCLUSIONS

High risk of postoperative cancer pain, particularly among the high PCA dose group, could possibly indicate inadequate pain control, and presence of modifiable risk factors warrants more aggressive pain management strategies perioperatively.

Programmed intermittent bolus infusion vs. continuous infusion for erector spinae plane block in video-assisted thoracoscopic surgery: A double-blinded randomised controlled trial

BACKGROUND

The optimal form of administration for erector spinae plane block has not been established.

OBJECTIVE

To compare the efficacy of programmed intermittent bolus infusion (PIB) and continuous infusion for erector spinae plane block.

DESIGN

A prospective, randomised, double-blind study.

SETTING

A single centre between June 2019 and March 2020.

PATIENTS

Included patients had an American Society of Anesthesiologists physical status 1 to 3 and were scheduled for video-assisted thoracic surgery.

INTERVENTIONS

Patients were randomised to receive continuous infusion (0.2% ropivacaine 8 ml h-1; Group C) or PIB (0.2% ropivacaine 8 ml every 2 h; Group P).

MAIN OUTCOME MEASURES

The primary outcome was the number of desensitised dermatomes in the midclavicular line, measured 21 h after first bolus injection.

RESULTS

Fifty patients were randomly assigned to each group; finally, the data of 24 and 25 patients in Group C and P, respectively, were analysed. The mean difference in the number of desensitised dermatomes in the midclavicular line at 5 and 21 h after the initial bolus administration was 1.0 [95% confidence interval (CI) 0.5 to 1.5] and 1.6 (95% CI 1.1 to 2.0), respectively, which was significantly higher in Group P than in Group C (P < 0.001). The median difference in rescue morphine consumption in the early postoperative period (0 to 24 h) was 4 (95% CI 1 to 8) mg, which was significantly lower in Group P (P = 0.035). No significant difference in the postoperative numerical rating scale score was found between the groups.

CONCLUSIONS

PIB for erector spinae plane block in video-assisted thoracic surgery resulted in a larger anaesthetised area and required a lower anaesthetic dose to maintain the analgesic effect. Therefore, it is more suitable for erector spinae plane block than continuous infusion.

TRIAL REGISTRATION

UMIN Clinical Trials Registry (UMIN-CTR, ID: UMIN000036574, Principal investigator: Taro Fujitani, 04/22/2019, https://upload.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000041671).

A Comparative Study of Bilateral Erector Spinae Block Versus Intravenous Dexmedetomidine for Perioperative Pain Management in Patients Undergoing Off-Pump Coronary Artery Bypass Grafting - A Single-Blind Randomized Controlled Trial

OBJECTIVE

Regional analgesia, along with general anesthesia, reduce postoperative pain. In this study, the authors compared the erector spinae plane (ESP) block having dexmedetomidine as an adjuvant with conventional pain management along with intravenous dexmedetomidine.

DESIGN

Prospective randomized single-blinded trial.

SETTING

Tertiary care teaching hospital.

PARTICIPANTS

All of the patients scheduled for elective off-pump coronary artery bypass grafting with an ejection fraction of >45%.

INTERVENTIONS

After obtaining institutional ethical committee approval, 130 patients were randomized into Group E and Group D. Group E patients received ESP block bilaterally with 25 mL of bupivacaine plus 0.5 μg/kg of dexmedetomidine. The patients in Group D received conventional intravenous analgesia, as well as a 0.7 μg/kg of dexmedetomidine bolus, followed by a 0.3 μg/kg dexmedetomidine infusion during surgery and continued postoperatively for 24 hours. Group E patients received 8 mL/h of bupivacaine infusion bilaterally for 24 hours.

MEASUREMENTS

The primary outcome assessed was pain scores in the postoperative period. The secondary outcomes assessed were postoperative rescue analgesic consumption, time to first rescue analgesia, intraoperative fentanyl consumption, duration of mechanical ventilation, and duration of intensive care unit (ICU) stay.

RESULTS

Both groups were comparable in demographic characteristics. The postoperative pain scores from 4 hours to 12 hours were lower in Group E compared with Group D. The pain scores at 24 hours were not significantly different between groups. Postoperative fentanyl consumption in Group E (99.23 ± 50.19 μg) was significantly lower than in Group D (181.15 ± 82.92 μg), with a p value of 0.001. Time to first rescue analgesia was significantly longer in Group E, with a median score of 8 hours when compared with that of 4 hours in Group D, with a p value of 0.01. Intraoperative fentanyl consumption was significantly lower in Group E (392.15 ± 55.36 μg) compared with Group D (604.00 ± 131.87 μg; p = 0.001). There were no significant differences in the duration of mechanical ventilation in both groups. Duration of ICU stay was significantly lower in Group E (51.95 ± 8.54 hours) when compared with Group D (59.06 ± 8.68 hours) (p = 0.001).

CONCLUSIONS

Erector spinae fascial plane blocks appeared to reduce postoperative pain scores in off-pump coronary artery bypass graft patients. Furthermore, ESP block was beneficial in terms of less intraoperative and postoperative opioid consumption, longer time to first rescue analgesia, and shorter ICU stay.

Combined Programmed Intermittent Bolus Infusion With Continuous Infusion for the Thoracic Paravertebral Block in Patients Undergoing Thoracoscopic Surgery: A Prospective, Randomized, and Double-blinded Study

BACKGROUND

Continuous thoracic paravertebral block (TPVB) connected with patient-controlled analgesia (PCA) pump is an effective modality to reduce postoperative pain following thoracic surgery. For the PCA settings, the programmed intermittent bolus infusion (PIBI) and continuous infusion (CI) are commonly practiced. However, the comparative effectiveness between the 2 approaches has been inconsistent. Thus, the aim of this study was to explore the optimal PCA settings to treat postthoracotomy pain by combing PIBI and CI together.

METHODS

All enrolled patients undergoing thoracoscopic surgery accepted ultrasound-guided TPVB catheterization before the surgery and then were randomly allocated in to 3 groups depending on different settings of the PCA pump connecting to the TPVB catheter: the PIBI+CI, PIBI, and CI groups. Numerical Rating Scales were evaluated for each patient at T1 (1 h after extubation), T2 (12 h after the surgery), T3 (24 h after the surgery), T4 (36 h after the surgery), and T5 (48 h after the surgery). Besides, the consumptions of PCA ropivacaine, the number of blocked dermatomes at T3, and the requirement for extra dezocine for pain relief among the 3 groups were also compared.

RESULTS

First, the Numerical Rating Scale scores in the PIBI+CI group were lower than the CI group at T2 and T3 (P<0.05) when patients were at rest and were also lower than the CI group at T2, T3, and T4 (P<0.01) and the PIBI group at T3 when patients were coughing (P<0.01). Second, the 2-day cumulative dosage of PCA in the PIBI+CI group was lower than both the CI and PIBI groups (P<0.01). Third, the number of blocked dermatomes in the PIBI and PIBI+CI groups were comparable and were both wider than the CI group at T3 (P<0.01). Finally, a smaller proportion (not statistically significant) of patients in the PIBI+CI group (5.26%, 2/38) had required dezocine for pain relief when compared with the PIBI group (19.44%, 7/36) and the CI group (15.79%, 6/38).

CONCLUSIONS

The combination of PIBI and CI provides superior analgesic modality to either PIBI or CI alone in patients undergoing thoracoscopic surgery. Therefore, it should be advocated to improve the management of postoperative pain, clinical outcomes, and ultimately patient satisfaction.

Basal Infusion versus Automated Boluses and a Delayed Start Timer for "Continuous" Sciatic Nerve Blocks following Ambulatory Foot and Ankle Surgery A Randomized, Clinical Trial

BACKGROUND.

The common technique using a basal infusion for an ambulatory continuous peripheral nerve blocks frequently results in exhaustion of the local anesthetic reservoir prior to resolution of surgical pain. We sought to improve and prolong analgesia by delaying initiation using an integrated timer and delivering a lower hourly volume of local anesthetic as automated boluses. We hypothesized that, compared with a traditional continuous infusion, ropivacaine administered with automated boluses at a lower dose and 5-hour delay would (1) provide at least noninferior analgesia [difference in average pain no greater than 1.7 points] while both techniques were functioning [average pain score day after surgery]; and, (2) result in a longer duration [dual primary outcomes].

METHODS.

Participants (n = 70) undergoing foot or ankle surgery with a popliteal-sciatic catheter received an injection of ropivacaine 0.5% with epinephrine (20 mL) then were randomized to receive ropivacaine (0.2%) as either continuous infusion (6 mL/h) initiated prior to discharge, or automated boluses (8 mL every 2 h) initiated 5 hours following discharge using a timer. Both groups could self-deliver supplemental boluses (4 mL, lockout 30 min); participants and outcomes assessors were blinded to randomization. All randomized participants were included in data analysis.

RESULTS.

The day following surgery, participants with automated boluses had a median [IQR] pain score of 0.0 [0.0 to 3.0] vs. 3.0 [1.8 to 4.8] for the continuous infusion group: odds ratio 3.1 (95% CI 1.23 to 7.84, p=0.033) adjusting for BMI. Reservoir exhaustion in automated boluses group occurred after a median [IQR] of 119 h [109,125] vs. 74 h [57,80] for continuous infusion group: difference 47h (95% CI: 38 to 55), P<0.001 adjusting for BMI.

CONCLUSIONS

For popliteal-sciatic catheters, replacing a continuous infusion initiated before discharge with automated boluses and a start-delay timer resulted in better analgesia and longer infusion duration.

Programmed intermittent epidural bolus in parturients: A meta-analysis of randomized controlled trials

BACKGROUND

To evaluate the efficacy and safety of programmed intermittent epidural bolus (PIEB) in parturients.

METHODS

The PubMed, Embase, and the Cochrane Library (from inception to July 2021) were searched for identification of randomized placebo-controlled trials in which PIEB was applied in parturients. The outcomes were the effect of analgesia, satisfaction score, mode of delivery, duration of labor, neonatal condition, and adverse events. The pooled odds ratios (OR), weighted mean difference (WMD), and 95% confidence intervals (CIs) were calculated using random- and fixed-effects models.

RESULTS

PIEB was found to be associated with decreased total consumption of ropivacaine (WMD = -15.83, 95% CI: -19.06 to -12.60, P < .00001; I2 = 61%; P for heterogeneity = .04), total consumption of sufentanil (WMD = -4.93, 95% CI: -6.87 to 2.98, P < .00001; I2 = 68%; P for heterogeneity = .05), numbers of patients who require patient-controlled epidural analgesia bolus (OR = 0.27, 95% CI: 0.14-0.51, P < .0001; I2 = 65%; P for heterogeneity = .01), the number of attempts (WMD = -4.12, 95% CI: -7.21 to -1.04, P = .009; I2 = 100%; P for heterogeneity < .00001), rate of breakthrough pain (OR = 0.47, 95% CI: 0.28-0.80, P = .005; I2 = 47%; P for heterogeneity = .09). Eight studies focus on the duration of analgesia. After by meta-analysis, we found that the pain visual analogue scale (VAS) score at 30 minutes, 2 hours, 4 hours, and 5 hours in PIEB group was significantly lower when compared with control group, (WMD = -0.15, 95% CI: -0.26 to -0.04, P = .006; I2 = 0%; P for heterogeneity = .64), (WMD = -0.79, 95% CI: -1.32 to 0.25, P = .004; I2 = 97%; P for heterogeneity < .00001), (WMD = -1.00, 95% CI: -1.08 to -0.91, P < .00001; I2 = 0%; P for heterogeneity = .67), (WMD = -1.81, 95% CI: -3.23 to -0.39, P = .01; I2 = 98%; P for heterogeneity < .00001), respectively. Nineteen studies discussed the mode of delivery between 2 groups. The results suggest that the rate of normal delivery is significantly higher in PIEB group compared with control group (OR = 1.37, 95% CI: 1.08-1.75, P = .01). The time of first and second stage of labor are significantly shorter in PIEB group compared with control group, the result is (WMD = -10.52, 95% CI: -14.74 to 4.76, P < .00001; I2 = 0%; P for heterogeneity = .86), (WMD = -1.48, 95% CI: -2.26 to -0.69, P = .0002; I2 = 35%; P for heterogeneity = .10), respectively. Thirteen studies concerned the satisfaction score of patients. The satisfaction score of patients in the PIEB group was significantly higher when compared with control group (WMD = 0.91, 95% CI: 0.42-1.39, P = .0003; I2 = 98%; P for heterogeneity < .00001). The Apgar score at 1, 5 minutes in PIEB group are significantly higher (WMD = 0.07, 95% CI: 0.02-0.13 P = .007; I2 = 55%; P for heterogeneity = .04), (WMD = -0.08, 95% CI: -0.12 to -0.05, P < .00001; I2 = 21%; P for heterogeneity = .27), respectively.

CONCLUSIONS

PIEB is a good alternative for labor analgesia with better analgesic effect, maternal and infant outcome.

Regional Anesthesia Techniques for Pain Management for Laparoscopic Surgery: a Review of the Current Literature

Purpose of Review

The field of regional anesthesia has evolved tremendously in the last 15 years. New anesthesia protocols for ambulatory surgery and enhanced recovery after surgery have been developed as well. The focus of these techniques and protocols has centered on patient satisfaction and pain control while minimizing the use of opioids. The field of ambulatory surgery and anesthesia continues to evolve, and regional anesthesia and its plane techniques are at the center of these changes.

Recent Findings

Recent research has shown that regional techniques contribute to better pain control and patient experience and may decrease patient readmission rates. The safety of these techniques has been validated when performed by experienced practitioners. New techniques such as the erector spinae block (ESP) have been studied in the setting of laparoscopic surgery with promising results.

Summary

Regional anesthesia techniques for patients presenting for laparoscopic surgery are safe and seem to provide benefits. Those are related to patient experience, pain control, and readmission rates. Different techniques can be applied to a specific type of intervention. Application of these techniques depend on the clinical picture and patient. Future research may help us clarify how these techniques may improve patient satisfaction and operating room efficiency. New regional blocks may also develop based on what we know today.

Programmed, intermittent boluses versus continuous infusion to the sciatic nerve - a non-inferiority randomized, controlled trial

BACKGROUND

Trials comparing programmed, intermittent boluses (PIB) and continuous infusion in catheter-based nerve blocks found no analgesic differences. However, as these trials used equal doses of local anesthetic (LA), the time of action of each bolus was not accounted for. Therefore, the dose-sparing benefits of PIB may have been overlooked. We compared the analgesic effect of boluses administered in intervals resembling the time of action of each bolus with continuous infusion. We hypothesized that PIB provided non-inferior analgesia despite consuming less LA.

METHODS

Eighty-one patients undergoing fore- and midfoot surgery receiving a catheter-based sciatic nerve block were randomized to ropivacaine 0.2% as PIB of 10 ml every 8th hour or as continuous infusion, 6 ml h^-1 . All participants could also receive boluses of 10 ml every 4th hour as needed. A non-inferiority randomized controlled design was used. Primary outcome was pain (VAS, 0-100 mm) for 72 h using area under curve (AUC) calculation. We assumed a linear relationship between mean VAS and AUC-VAS and used a non-inferiority margin of VAS = 20 mm, corresponding to AUC-VAS = 1440 mm h.

RESULTS

Mean difference in AUC-VAS was -416 mm h (95% CI -1076 to 244; p = .217) between continuous infusion (mean AUC-VAS 1206 mm h) and PIB (mean AUC-VAS 1621 mm h), establishing non-inferiority. Mean total LA consumption was significantly larger for continuous infusion compared to PIB ((468 ml (95% CI 458 to 478) vs. 136 ml (95% CI 123 to 148); p < 0.0001)).

CONCLUSIONS

PIB provided non-inferior analgesia compared to continuous infusion for 72 postoperative hours despite using significantly less LA.

PROSPECT guidelines for video-assisted thoracoscopic surgery: a systematic review and procedure-specific postoperative pain management recommendations

Video‐assisted thoracoscopic surgery has become increasingly popular due to faster recovery times and reduced postoperative pain compared with thoracotomy. However, analgesic regimens for video‐assisted thoracoscopic surgery vary significantly. The goal of this systematic review was to evaluate the available literature and develop recommendations for optimal pain management after video‐assisted thoracoscopic surgery. A systematic review was undertaken using procedure‐specific postoperative pain management (PROSPECT) methodology. Randomised controlled trials published in the English language, between January 2010 and January 2021 assessing the effect of analgesic, anaesthetic or surgical interventions were identified. We retrieved 1070 studies of which 69 randomised controlled trials and two reviews met inclusion criteria. We recommend the administration of basic analgesia including paracetamol and non‐steroidal anti‐inflammatory drugs or cyclo‐oxygenase‐2‐specific inhibitors pre‐operatively or intra‐operatively and continued postoperatively. Intra‐operative intravenous dexmedetomidine infusion may be used, specifically when basic analgesia and regional analgesic techniques could not be given. In addition, a paravertebral block or erector spinae plane block is recommended as a first‐choice option. A serratus anterior plane block could also be administered as a second‐choice option. Opioids should be reserved as rescue analgesics in the postoperative period.

Benefits and risks of intermittent bolus erector spinae plane block through a catheter for patients after cardiac surgery through a lateral mini-thoracotomy: A propensity score matched retrospective cohort study

STUDY OBJECTIVE

A lateral mini-thoracotomy approach to cardiac surgery causes severe and complicated postoperative pain compared to the sternotomy approach. In this study we assessed the benefits and risks of intermittent bolus erector spinae plane block (ESPB) via a catheter for patients who underwent cardiac surgery through a lateral mini-thoracotomy.

DESIGN

A propensity score-matched retrospective cohort study.

SETTING

University hospital.

PATIENTS

452 consecutive patients that underwent cardiac surgery through a lateral mini-thoracotomy from 2018 to 2020.

INTERVENTIONS

Patients who received intermittent bolus ESPB through a catheter for 3 days (ESPB group, n = 93) were compared with patients who did not receive any regional anesthesia (Control group, n = 174) after propensity score matching.

MEASUREMENTS

The primary endpoint was postoperative in-hospital cumulative opioid consumption (calculated as oral morphine milligram equivalents, MME). The secondary outcomes were intraoperative sufentanil doses, therapeutic use of antiemetic, pulmonary infection (assessed using a modified clinical pulmonary infection score, CPIS), durations of ICU and hospital stays, and ESPB related/unrelated complications.

MAIN RESULTS

There is a lower oral MME in the ESPB group, 266 ± 126 mg in the ESPB group vs. 346 ± 105 mg in the control group (95% CI -113 to -46; P < 0.01). Fewer patients received therapeutic antiemetic agents in the ESPB group (30% vs. 42%, odds ratio 0.58; 95% CI 0.34 to 0.99; P = 0.04). The modified CPIS in the ESPB group is lower: 1.4 ± 0.9 vs. 2.0 ± 1.0 (95% CI -0.9 to -0.3; P < 0.01) on postoperative day 1; 1.6 ± 0.9 vs. 2.0 ± 0.9 (95% CI -0.7 to -0.2; P < 0.01) on postoperative day 2. The observed complications associated with ESPB include pneumothorax (1%), staxis around stomas (5%), hypotension (1%), catheter displacement (3%), and catheter obstruction (2%). None of the patients had any adverse outcomes.

CONCLUSION

Intermittent bolus ESPB is relatively safe and correlated with a reduction in the use of opioids and antiemetics for cardiac surgery through a lateral mini-thoracotomy.

Impact of paravertebral blocks on analgesic and non-analgesic outcomes after video-assisted thoracoscopic surgery: A propensity matched cohort study

BACKGROUND

Regional analgesic techniques such as paravertebral blocks (PVBs) have been popularized for analgesia following video-assisted thoracoscopic surgery (VATS). In this single center retrospective propensity matched cohort of subjects, we investigate the impact of paravertebral blocks on the analgesic and non-analgesic outcomes.

METHODS

Institutional database was queried to identify all patients undergoing VATS between January 2013 and July 2019 and these patients were divided into those who received paravertebral blocks in combination with general anesthesia (GA) [PVB group] and those who received GA without paravertebral blocks [GA group]. Propensity score matching based on common patient confounders were used to identify patients in each group. Primary outcomes of the study were average pain scores and opioid consumption in the first 24 hours. Secondary analgesic outcomes included pain scores and opioid requirements at other timepoints over the first 48 hours. Non analgesic outcomes were obtained from STS General Thoracic Surgery Database and included length of hospital stay, need for ICU admission, composite outcome of any complication during the hospital course and 30-day mortality. Exploratory analyses were conducted to investigate the impact of PVB on analgesia following different types of surgery and as to whether any other covariates had a greater influence on the included patient centered outcomes.

MAIN RESULTS

After propensity score matching, a total of 520 patients (260 per group) were selected for the study out of 1095 patients. The opioid consumption in terms of oral morphine milligram equivalent (MME) [Median (IQR)] for the first 24 hours was significantly lower with the use of PVB [PVB group- 78.5 (96.75); GA group-127.0 (111.5); p<0.001] while the average pain scores in the first 24 hours did not differ significantly [PVB group-4.71 (2.28); GA group-4.85 (2.30); p = 0.70]. The length of hospital stay, opioid requirements at other timepoints, need for ICU admission in the immediate post-operative period and the composite outcome-'any complication' (35% vs 48%) were significantly lower with the use of PVB. Subgroup analysis showed a longer duration of benefit following major lung surgeries compared to others.

CONCLUSION

Paravertebral blocks reduced the length of stay and opioid consumption up to 48 hours after VATS without significantly impacting pain scores.

Single and Repeated Intrapleural Ropivacaine Administration: A Plasma Concentration and Pharmacodynamics Study

Background

Intrapleural analgesia has been increasingly recommended for postoperative analgesia after thoracic surgery. However, the analgesic effect provided by a single intrapleural administration is time limited. This study reports the efficacy and safety of repeated intrapleural 0.75% ropivacaine administration after thoracoscopic surgery.

Methods

Twenty patients were randomly divided into two groups: a single administration group receiving a single intrapleural injection of 0.75% ropivacaine 15 mL (single administration group, SA group), and a repeated administration group with an intrapleural injection of 0.75% ropivacaine 15 mL every 4h for 4 doses (repeated administration group, RA group). The primary outcomes of this study were the peak plasma concentration of ropivacaine and 24h morphine consumption. The secondary outcomes were pain score, patient satisfaction, extubation time, hospital length of stay, and adverse reactions.

Results

In SA group, the highest plasma concentration after intrapleural administration of 0.75% ropivacaine 15 mL was 1345±364 μg/L. The highest plasma concentration in RA group after the fourth administration was 1864±492 μg/L. The 24h morphine consumption in RA group was significantly less than that in SA group (9.0±5.66 vs 15.9±3.48 mg, P=0.004). The NRS scores at rest and while coughing of patients in RA group were significantly lower than those in SA group at 5, 9, 13, 17 and 24h after operation. The patients in RA group had higher satisfaction than those in SA group. There was no significant difference in postoperative adverse events, drainage tube placement days and hospital length of stay between the two groups.

Conclusion

Repeated intrapleural administration with 0.75% ropivacaine, 15 mL every 4h for 4 doses after video-assisted thoracoscopic lobectomies, can provide a more durable and more effective analgesic effect than single intrapleural administration. Repeated intrapleural administration of ropivacaine is an effective postoperative method of analgesia resulting in higher patient satisfaction. Moreover, it was also able to keep the plasma concentration of ropivacaine within a possible safe range.

Clinical Trial Registration Number

ChiCTR-IOR-17010560.

Erector Spinae Regional Anesthesia for Robotic Coronary Artery Bypass Surgery Is Not Associated With Reduced Postoperative Opioid Use: A Retrospective Observational Study

OBJECTIVE

Regional anesthesia techniques are gaining traction in cardiac surgery. The aim of this study was to compare the analgesic efficacy of erector spinae plane block catheters (ESPBC), serratus anterior plane block catheters (SAPBC), and paravertebral single-shot block (PVB) versus no block after robotic minimally invasive direct coronary artery bypass (MIDCAB).

DESIGN

This was a retrospective observational study of routinely recorded data.

SETTING

The study was performed at a single healthcare system.

PARTICIPANTS

All patients underwent robotic MIDCAB.

INTERVENTION

Data were analyzed from 346 patients during a 53-month period. The clinical data warehouse was queried for all robotic MIDCAB surgeries. Variables abstracted included type of nerve block, age, sex, use of adjuncts, Society of Thoracic Surgeons predicted short length of stay (PSLOS), total opioid consumption during the 72 hours after surgery, and postoperative hospital length of stay (LOS). The primary outcome was total oral morphine milligram equivalents (MME) consumed during the first 72 hours after surgery. The secondary outcome was hospital LOS.

MEASUREMENTS AND MAIN RESULTS

In a model adjusting for PSLOS, the authors did not observe an association between ESPBC and the reduction of total administered oral MME within 72 hours after surgery. There was no significant difference in MME when comparing patients who received PVB to patients with ESPBC. Older age and female sex were associated with significantly lower MME. Patients who received ESPBC had a significantly shorter hospital LOS than patients with SAPBC.

CONCLUSIONS

These findings suggested that postoperative pain after MIDCAB surgery might not be completely covered by ESPBC. Prospective studies are needed to further elucidate the value of this technique for robotic MIDCAB.

Distribution of injectate administered through a catheter inserted by three different approaches to ultrasound-guided thoracic paravertebral block: a prospective observational study

Background

Despite the popularity of continuous thoracic paravertebral block (TPVB), there is a paucity of information on catheter tip position and distribution of injectate through the catheter. We observed, in real time, the spread of dye, the catheter tip position and sensory block levels produced with three different (intercostal (IC), transverse process sagittal (TS) and paralaminar (PL)) approaches to ultrasound-guided TPVB in patients undergoing video-assisted thoracoscopic surgery.

Methods

After the induction of general anesthesia, ultrasound-guided TPVB was conducted with a patient in the lateral decubitus position. During surgery, 10 mL of dye was injected through a catheter to observe the catheter tip and the dye distribution under thoracoscopy. Dermatomal sensory block levels were measured postoperatively.

Results

Ten patients for each of three different approaches completed the study. There were a variety of dye spreading patterns. The median (range) number of segmental levels stained with dye was 1.5 (1–4), 3 (1–4) and 3 (1–5) with the IC, TS and PL approaches, respectively. We observed that a catheter tip was present at the same segmental paravertebral space as intended in 50%–90% of patients using these approaches. The median (range) number of dermatomes with sensory blockade at 6 hours after block was 2.5 (1–4), 3 (2–8) and 3 (1–8) with the IC, TS and PL approaches, respectively.

Conclusions

Although a bolus injection through a catheter for ultrasound-guided TPVB produced multiple levels of spread and sensory blockade in more than half the patients, considerable differences existed in the spread regardless of approach.

Optimum interval time of programmed intermittent epidural bolus of ropivacaine 0.08% with sufentanyl 0.3 μg/mL for labor analgesia: a biased-coin up-and-down sequential allocation trial

BACKGROUND

The programmed intermittent epidural bolus (PIEB) technique is widely used in labor analgesia, but the parameter settings of PIEB have not yet been standardized. We designed a study to identify the optimal interval duration for PIEB using 10 mL of ropivacaine 0.08% and sufentanyl 0.3 μg/mL, a regimen commonly used to control labor pain in China, to provide effective analgesia in 90% of women during the first stage of labor without breakthrough pain.

METHODS

We conducted a double-blind sequential allocation trial to obtain the effective interval 90% (EI90%) during the first stage of labor between April 2019 and May 2019. This study included the American Society of Anesthesiologists physical status II-III nulliparous parturients at term, who requested epidural analgesia. The bolus volume was fixed at 10 mL of ropivacaine 0.08% with sufentanyl 0.3 μg/mL. Participants were divided into four groups (groups 60, 50, 40, and 30) according to the PIEB intervals (60, 50, 40, and 30 min, respectively). The interval duration of the first parturient was set at 60 min and that of subsequent parturients varied according to a biased-coin design. The truncated Dixon and Mood method and the isotonic regression analysis method were used to estimate the EI90% and its 95% confidence intervals (CIs).

RESULTS

Forty-four women were enrolled in this study. The estimated optimal interval was 44.1 min (95% CI 41.7-46.5 min) and 39.5 min (95% CI 32.5-50.0 min), using the truncated Dixon and Mood method and isotonic regression analysis, respectively. The maximum sensory block level above T6 was in nearly 20% of parturients in group 30; however, 5.3%, 0%, and 0% of the parturients presented with sensory block level above T6 in groups 40, 50, and 60, respectively. There were no cases of hypotension and only one parturient complained of motor block.

CONCLUSION

With a fixed 10 mL dose of ropivacaine 0.08% with sufentanyl 0.3 μg/mL, the optimal PIEB interval is about 42 min. Further studies are warranted to define the efficacy of this regimen throughout all stages of labor.

TRIAL REGISTRATION

Chinese Clinical Trial Registry, ChiCTR1900022199; http://www.chictr.org.cn/com/25/historyversionpuben.aspx?regno=ChiCTR1900022199.

Robotic Thoracic Surgery

Minimally invasive surgery for diseases of the chest offsets the morbidity of painful thoracic incisions while allowing for meticulous dissection of major anatomic structures. This benefit translates to improved outcomes and recovery following the surgical management of benign and malignant esophageal pathologic condition, mediastinal tumors, and lung resections. This anatomic region is particularly amenable to a robotic approach given the fixed space and need for complex intracorporeal dissection. As robotic platforms continue to evolve, more complex thoracic surgical interventions will be facilitated, translating to improved outcomes for our patients.

Thoracic-paravertebral blocks: comparative anatomical study with different injection techniques and volumes

Background and objectives

We hypothesized that different injection techniques and volumes in thoracic-paravertebral blocks (TPVB) lead to different patterns of dye spread. In particular, we investigated whether an alternating injection technique leads to complete staining of all adjacent intercostal nerves.

Methods

This comparative anatomical investigation was performed using 10 or 20 mL of dye (Alcian Blue) in 10 unfixed donor cadavers (54 injections) that were designated for education or research purposes.

Results

In landmark-guided TPVB, the thoracic-paravertebral space (TPVS) was either not stained at all (spread of dye in the paraspinal muscles, n=3) or the dye was predominantly found in the epidural space (n=3). In ultrasound-guided TPVB, the TPVS was correctly identified in all cases (n=48). The sympathetic trunk was stained in 84.6% of injections (multi-injection technique: 100%), independent of injection technique and volume. The epidural space was stained more frequently (p≤0.001) if both the puncture site (sagittal transducer position) and guidance of the needle were more medial (77.8%). Finally, a higher injection volume (20 vs 10 mL) resulted in a higher number of stained intercostal nerves (p=0.04).

Conclusion

For ultrasound-guided techniques, a higher injection volume resulted in a larger number of stained intercostal nerves. Staining of the sympathetic trunk was independent of the injection technique. Epidural spread was observed significantly less frequently if the injection was lateral (transducer transversal) or with a strictly cranial injection direction (transducer sagittal). Landmark-guided injections reliably achieved the TPVS (and the epidural space) only after a needle advance of 2.5 cm after initial contact with the transverse process.

Local anaesthetic delivery regimens for peripheral nerve catheters: a systematic review and network meta-analysis

There are numerous possible techniques for delivering local anaesthetic through peripheral nerve catheters. These include continuous infusions, patient-controlled boluses and programmed intermittent boluses. The optimal delivery regimen of local anaesthetic is yet to be conclusively established. In this review, we identified prospective trials of delivery regimens through peripheral nerve catheters. Our primary outcome was visual analogue scale scores for pain at 48 h. Secondary outcomes were: visual analogue scores at 24 h; patient satisfaction scores; rescue opioid use; local anaesthetic consumption; and nausea and vomiting. Network meta-analysis was used to compare these outcomes. Predefined sub-group analyses were performed. Thirty-three studies enrolling 1934 participants were included. In comparison with continuous infusion, programmed intermittent boluses improved visual analogue pain scores at both 48 and 24 h, the weighted mean difference (95%CI) being -0.63 (-1.12 to -0.14), p = 0.012 and -0.48 (-0.92 to -0.03), p = 0.034, respectively. Programmed intermittent boluses also improved satisfaction scores, the weighted mean difference (95%CI) being 0.70 (0.10-1.31), p = 0.023, and reduced rescue opioid use, the weighted mean difference (95%CI) in oral morphine equivalent at 24 h being -23.84 mg (-43.90 mg to -3.77 mg), p = 0.020. Sub-group analysis revealed that these findings were mostly confined to lower limb and truncal catheter studies; there were few studies of programmed intermittent boluses for upper limb catheters. Programmed intermittent boluses may provide optimal delivery of a local anaesthetic through peripheral nerve catheters. Further research is warranted, particularly to delineate the differences between upper and lower limb catheter locations, which will help clarify the clinical relevance of these findings.

A Comparative Study of Automated Pulsed Bolus Versus Continuous Basal Infusion on Distribution of Dye in the Paravertebral Space in a Cadaver

Adequate pain control following thoracic surgery is important to enhance post-operative recovery. Paravertebral catheters have been reported to have a variety of clinical applications, including the blunting of surgical pain, lessening the need for opioids, and improvement in post-operative ventilation. The spread of local anesthesia to multiple paravertebral spaces is needed to establish an effective block. We have determined that the spread of contrast dye by a catheter in the thoracic paravertebral space is greater in a programmed intermittent bolus than in a continuous basal infusion.