Fascial plane blocks in regional anaesthesia: how problematic is simplification?

Serratus anterior and pectoralis plane blocks for robotically assisted mitral valve repair: a randomised clinical trial

BACKGROUND

Minimally invasive cardiac surgery provokes substantial pain and therefore analgesic consumption. The effect of fascial plane blocks on analgesic efficacy and overall patient satisfaction remains unclear. We therefore tested the primary hypothesis that fascial plane blocks improve overall benefit analgesia score (OBAS) during the initial 3 days after robotically assisted mitral valve repair. Secondarily, we tested the hypotheses that blocks reduce opioid consumption and improve respiratory mechanics.

METHODS

Adults scheduled for robotically assisted mitral valve repairs were randomised to combined pectoralis II and serratus anterior plane blocks or to routine analgesia. The blocks were ultrasound-guided and used a mixture of plain and liposomal bupivacaine. OBAS was measured daily on postoperative Days 1-3 and were analysed with linear mixed effects modelling. Opioid consumption was assessed with a simple linear regression model and respiratory mechanics with a linear mixed model.

RESULTS

As planned, we enrolled 194 patients, with 98 assigned to blocks and 96 to routine analgesic management. There was neither time-by-treatment interaction (P=0.67) nor treatment effect on total OBAS over postoperative Days 1-3 with a median difference of 0.08 (95% confidence interval [CI]: -0.50 to 0.67; P=0.69) and an estimated ratio of geometric means of 0.98 (95% CI: 0.85-1.13; P=0.75). There was no evidence of a treatment effect on cumulative opioid consumption or respiratory mechanics. Average pain scores on each postoperative day were similarly low in both groups.

CONCLUSIONS

Serratus anterior and pectoralis plane blocks did not improve postoperative analgesia, cumulative opioid consumption, or respiratory mechanics during the initial 3 days after robotically assisted mitral valve repair.

CLINICAL TRIAL REGISTRATION

NCT03743194.

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).

Postoperative recovery with continuous erector spinae plane block or video-assisted paravertebral block after minimally invasive thoracic surgery: a prospective, randomised controlled trial

BACKGROUND

PROcedure SPECific Postoperative Pain ManagemenT (PROSPECT) guidelines recommend erector spinae plane (ESP) block or paravertebral block (PVB) for postoperative analgesia after video-assisted thoracoscopic surgery (VATS). However, there are few trials comparing the effectiveness of these techniques on patient-centric outcomes, and none evaluating chronic postsurgical pain (CPSP). Furthermore, there are no available trials comparing ultrasound-guided ESP with surgically placed PVB in this patient cohort.

METHODS

We conducted a two-centre, prospective, randomised, double-blind, controlled trial, comparing anaesthesiologist-administered, ultrasound-guided ESP catheter with surgeon-administered, video-assisted PVB catheter analgesia among 80 adult patients undergoing VATS. Participants received a 20 ml bolus of levobupivacaine 0.375% followed by infusion of levobupivacaine 0.15% (10-15 ml h^-1) for 48 h. Primary outcome was Quality of Recovery-15 score (QoR-15) at 24 h. Secondary outcomes included QoR-15 at 48 h, peak inspiratory flow (ml s^-1) at 24 h and 48 h, area under the pain verbal response score vs time curve (AUC), opioid consumption, Comprehensive Complication Index, length of stay, and CPSP at 3 months after surgery.

RESULTS

Median (25-75%) QoR-15 at 24 h was higher in ESP (n=37) compared with PVB (n=37): 118 (106-134) vs 110 (89-121) (P=0.03) and at 48 h: 131 (121-139) vs 120 (111-133) (P=0.03). There were no differences in peak inspiratory flow, AUC, Comprehensive Complication Index, length of hospital stay, and opioid consumption. Incidence of CPSP at 3 months was 12 (34%) for ESP and 11 (31%) for PVB (P=0.7).

CONCLUSIONS

Compared with video-assisted, surgeon-placed paravertebral catheter, erector spinae catheter improved overall QoR-15 scores at 24 h and 48 h but without differences in pain or opioid consumption after minimally invasive thoracic surgery.

CLINICAL TRIAL REGISTRATION

NCT04729712.

Peak plasma concentration of total and free bupivacaine after erector spinae plane and pectointercostal fascial plane blocks

PURPOSE

Erector spinae plane blocks (ESPB) and pectointercostal fascial (PIFB) plane blocks are novel interfascial blocks for which local anesthetic (LA) doses and concentrations necessary to achieve safe and effective analgesia are unknown. The goal of this prospective observational study was to provide the timing (Tmax) and concentration (Cmax) of maximum total and free plasma bupivacaine after ESPB in breast surgery and after PIFB in cardiac surgery patients.

METHODS

Erector spinae plane blocks or PIFBs (18 patients per block; total, 36 patients) were performed with 2 mg⋅kg-1 of bupivacaine with epinephrine 5 μg⋅mL-1. Our principal outcomes were the mean or median Cmax of total and free plasma bupivacaine measured 10, 20, 30, 45, 60, 90, 180, and 240 min after LA injection using liquid chromatography with tandem mass spectrometry.

RESULTS

For ESPB, the mean (standard deviation [SD]) total bupivacaine Cmax was 0.37 (0.12) μg⋅mL-1 (range, 0.19 to 0.64), and the median [interquartile range (IQR)] Tmax was 30 [50] min (range, 10-180). For ESPB, the mean (SD) free bupivacaine Cmax was 0.015 (0.017) μg⋅mL-1 (range, 0.003-0.067), and the median [IQR] Tmax was 30 [20] min (range, 10-120). After PIFB, mean plasma concentrations plateaued at 60-240 min. For PIFB, the mean (SD) total bupivacaine Cmax was 0.32 (0.21) μg⋅mL-1 (range, 0.14-0.95), with a median [IQR] Tmax of 120 [150] min (range, 30-240). For PIFB, the mean (SD) free bupivacaine Cmax was 0.019 (0.010) μg⋅mL-1 (range, 0.005-0.048), and the median [IQR] Tmax was 180 [120] min (range, 30-240). For both ESPB and PIFB, we observed no correlations between pharmacokinetic and demographic parameters.

CONCLUSION

Total and free bupivacaine Cmax observed after ESPB and PIFB with 2 mg⋅kg-1 of bupivacaine with epinephrine 5 μg⋅mL-1 were five to twenty times lower than levels considered toxic in the literature.

Regional and neuraxial anaesthesia techniques for spinal surgery: a scoping review

BACKGROUND

Whilst general anaesthesia is commonly used to undertake spine surgery, the use of neuraxial and peripheral regional anaesthesia techniques for intraoperative and postoperative analgesia is an evolving practice. Variations in practice have meant that it is difficult to know which modalities achieve optimal outcomes for patients undergoing spinal surgery. Our objective was to identify available evidence on the use of regional and neuraxial anaesthesia techniques for adult patients undergoing spinal surgery.

METHODS

This study was conducted using a framework for scoping reviews. This included a search of six databases searching for articles published since January 1980. We included studies that involved adult patients undergoing spinal surgery with regional or neuraxial techniques used as the primary anaesthesia method or as part of an analgesic strategy.

RESULTS

Seventy-eight articles were selected for final review. All original papers were included, including case reports, case series, clinical trials, or conference publications. We found that general anaesthesia remains the most common anaesthesia technique for this patient cohort. However, regional anaesthesia, especially non-neuraxial techniques such as fascial plane blocks, is an emerging practice and may have a role in terms of improving postoperative pain relief, quality of recovery, and patient satisfaction. In comparison with neuraxial techniques, the popularity of fascial plane blocks for spinal surgery has significantly increased since 2017.

CONCLUSIONS

Regional and neuraxial anaesthesia techniques have been used both to provide analgesia and anaesthesia for patients undergoing spinal surgery. Outcome metrics for the success of these techniques vary widely and more frequently use physiological outcome metrics more than patient-centred ones.

Ultrasound-guided erector spinae plane catheter versus video-assisted paravertebral catheter placement in minimally invasive thoracic surgery: comparing continuous infusion analgesic techniques on early quality of recovery, respiratory function and chronic persistent surgical pain: study protocol for a double-blinded randomised controlled trial

Background

Compared to conventional thoracotomy, minimally invasive thoracic surgery (MITS) can reduce postoperative pain, reduce tissue trauma and contribute to better recovery. However, it still causes significant acute postoperative pain. Truncal regional anaesthesia techniques such as paravertebral and erector spinae blocks have shown to contribute to postoperative analgesia after MITS. Satisfactory placement of an ultrasound-guided thoracic paravertebral catheter can be technically challenging compared to an ultrasound-guided erector spinae catheter. However, in MITS, an opportunity arises for directly visualised placement of a paravertebral catheter by the surgeon under thoracoscopic guidance. Alongside with thoracic epidural, a paravertebral block is considered the “gold standard” of thoracic regional analgesic techniques. To the best of our knowledge, there are no randomised controlled trials comparing surgeon-administered paravertebral catheter and anaesthesiologist-assisted erector spinae catheter for MITS in terms of patient-centred outcomes such as quality of recovery.

Methods

This trial will be a prospective, double-blinded randomised controlled trial. A total of 80 eligible patients will be randomly assigned to receive either an anaesthesiologist-assisted ultrasound-guided erector spinae catheter or a surgeon-assisted video-assisted paravertebral catheter, in a 1:1 ratio following induction of general anaesthesia for minimally assisted thoracic surgery. Both groups will receive the same standardised analgesia protocol for both intra- and postoperative periods. The primary outcome is defined as Quality of Recovery (QoR-15) score between the two groups at 24 h postoperative. Secondary outcomes include assessment of chronic persistent surgical pain (CPSP) at 3 months postoperative using the Brief Pain Inventory (BPI) Short Form and Short Form McGill (SF-15) questionnaires, assessment of postoperative pulmonary function, area under the curve for Verbal Rating Score for pain at rest and on deep inspiration versus time over 48 h, total opioid consumption over 48 h, QoR-15 at 48 h, and postoperative complications and morbidity as measured by the Comprehensive Complication Index.

Discussion

Despite surgical advancements in thoracic surgery, severe acute postoperative pain following MITS is still prevailing. This study will provide recommendations about the efficacy of an anaesthesia-administered ultrasound-guided erector spinae catheter or surgeon-administered, video-assisted paravertebral catheter techniques for early quality of recovery following MITS.

Trial registration

ClinicalTrials.govNCT04729712. Registered on 28 January 2021. All items from the World Health Organization Trial Registration Data Set have been included.

Mechanisms of action of fascial plane blocks: a narrative review

BACKGROUND

Fascial plane blocks (FPBs) target the space between two fasciae, rather than discrete peripheral nerves. Despite their popularity, their mechanisms of action remain controversial, particularly for erector spinae plane and quadratus lumborum blocks.

OBJECTIVES

This narrative review describes the scientific evidence underpinning proposed mechanisms of action, highlights existing knowledge gaps, and discusses implications for clinical practice and research.

FINDINGS

There are currently two plausible mechanisms of analgesia. The first is a local effect on nociceptors and neurons within the plane itself or within adjacent muscle and tissue compartments. Dispersion of local anesthetic occurs through bulk flow and diffusion, and the resulting conduction block is dictated by the mass of local anesthetic reaching these targets. The extent of spread, analgesia, and cutaneous sensory loss is variable and imperfectly correlated. Explanations include anatomical variation, factors governing fluid dispersion, and local anesthetic pharmacodynamics. The second is vascular absorption of local anesthetic and a systemic analgesic effect at distant sites. Direct evidence is presently lacking but preliminary data indicate that FPBs can produce transient elevations in plasma concentrations similar to intravenous lidocaine infusion. The relative contributions of these local and systemic effects remain uncertain.

CONCLUSION

Our current understanding of FPB mechanisms supports their demonstrated analgesic efficacy, but also highlights the unpredictability and variability that result from myriad factors at play. Potential strategies to improve efficacy include accurate deposition close to targets of interest, injections of sufficient volume to encourage physical spread by bulk flow, and manipulation of concentration to promote diffusion.

Visceral versus somatic pain: an educational review of anatomy and clinical implications

Somatic and visceral nociceptive signals travel via different pathways to reach the spinal cord. Additionally, signals regulating visceral blood flow and gastrointestinal tract (GIT) motility travel via efferent sympathetic nerves. To offer optimal pain relief and increase GIT motility and blood flow, we should interfere with all these pathways. These include the afferent nerves that travel with the sympathetic trunks, the somatic fibers that innervate the abdominal wall and part of the parietal peritoneum, and the sympathetic efferent fibers. All somatic and visceral afferent neural and sympathetic efferent pathways are effectively blocked by appropriately placed segmental thoracic epidural blocks (TEBs), whereas well-placed truncal fascial plane blocks evidently do not consistently block the afferent visceral neural pathways nor the sympathetic efferent nerves. It is generally accepted that it would be beneficial to counter the effects of the stress response on the GIT, therefore most enhanced recovery after surgery protocols involve TEB. The TEB failure rate, however, can be high, enticing practitioners to resort to truncal fascial plane blocks. In this educational article, we discuss the differences between visceral and somatic pain, their management and the clinical implications of these differences.