Abstract
Background:
Median sternotomy and chest tube sites drive pain following cardiac surgery. Prior research has demonstrated that pecto-intercostal fascial plane blocks (PIFB) reduce median sternotomy pain after cardiac surgery. Prior studies examining the addition of a rectus sheath block (RSB) to localize the insertion site of subxiphoid chest tubes have had mixed results.
Methods:
In this single-center, randomized, double-blind, placebo-controlled trial, 62 patients undergoing cardiac surgery with median sternotomy and subxiphoid chest tubes were randomized to receive PIFB and RSB with local anesthetic versus PIFB with local anesthetic and RSB with saline placebo. The primary outcome was pain at rest and with deep breathing in the first 24 hours after surgery. Secondary outcomes included total opioid consumption at 24 and 48 hours, performance on incentive spirometry in the first 24 hours, time to extubation, hospital and ICU length of stay, and Quality of Recovery-15 score.
Results:
There was no statistically significant difference between groups for the primary outcome, with mean area under the curve (AUC) for pain at rest in the first 24 hours 93.37 +/− 41.38 (sample mean +/− sample standard deviation) in the placebo group versus 86.11 +/− 42.78 in the bupivacaine group (p=0.51), and mean AUC for pain with deep breathing 135.55 +/− 43.74 in the placebo group versus 128.78 +/− 47.08 in the bupivacaine group (p=0.57). There were no differences in secondary outcomes between groups.
Conclusions:
Adding bilateral RSB to bilateral PIFB did not improve pain control or other outcomes for patients undergoing cardiac surgery.
Keywords: Regional anesthesia, fascial plane blocks, enhanced recovery after cardiac surgery
INTRODUCTION
Severe postoperative pain following cardiac surgery is associated with impaired pulmonary function, reduced ambulation, higher risk of thromboembolic events, and longer time to recovery.1–4 Recent guidelines have emphasized multimodal and opioid-sparing analgesia for cardiac surgery,5,6 including the use of fascial plane blocks (FPB). Meta-analysis of trials has demonstrated reduced pain in patients receiving FPB in cardiac surgery, but questions remain about which blocks are the most effective.7
Median sternotomy and mediastinal chest tubes are predominant drivers of pain following cardiac surgery.8–10 For median sternotomy pain, the pecto-intercostal fascial plane block (PIFB) targets anterior cutaneous branches of intercostal nerves that mediate sternotomy pain.11 A randomized controlled trial demonstrated that bilateral PIFBs after cardiac surgery resulted in lower postoperative pain in comparison to placebo.12 For the epigastrium, the point of entry for subxiphoid chest tubes, a rectus sheath block (RSB) will anesthetize the terminal branches of anterior cutaneous nerves that innervate the skin and muscle of the midline abdomen. In a case series of eight patients who received RSB following coronary artery bypass grafting (CABG), researchers reported low pain scores without opioids on postoperative day one.13
Few studies have examined combinations of PIFB with RSB in cardiac surgical patients. One single-blinded study compared PIFB with either RSB or surgeon infiltration and demonstrated lower postoperative pain scores, opioid utilization, and better respiratory performance in the RSB group, but with small effect size in most outcomes.14 In another study, 54 patients were randomized to PIFB with or without RSB, and the RSB group had lower opioid consumption for 48 hours without any difference in other outcomes.15
Given conflicting findings in prior studies, our aim is to more clearly determine whether combining bilateral RSB with PIFB provides clinically meaningful benefit beyond PIFB alone in patients undergoing cardiac surgery. We hypothesized that the addition of bilateral RSBs will provide improved analgesia at the subxiphoid chest tube insertion sites, leading to decreased pain scores and opioid requirements, with improved respiratory function and quality of recovery.
METHODS
Design and Patients
This single-center, prospective, randomized, placebo-controlled, double-blinded study was conducted at the Medical College of Wisconsin where it was approved by the Institutional Review Board (PRO00040365). It was registered May 24, 2021 with ClinicalTrials.gov, NCT04908449 [https://clinicaltrials.gov/study/NCT04908449].16
Enrollment occurred between June 19, 2023 and November 14, 2024. 18–85-year-old patients scheduled for CABG, single valve, or CABG + single valve procedures involving primary median sternotomy and subxiphoid chest tube placement with BMI 18–50 kg/m2 and weight > 60kg were invited to participate. Exclusion criteria included patient refusal; severe left ventricular dysfunction; preoperative or immediate postoperative need for advanced mechanical circulatory support; severe/uncontrolled pulmonary, hepatic, neurologic, or psychiatric disease; chronic opioid use; illicit drug use or alcohol use disorder within the past two years; amide local anesthetic allergy; local infection/wound at block site; and inability to communicate in English. All enrolled patients provided signed informed consent. Near the end of recruitment, an IRB amendment was approved to recruit two additional patients as two patients had been removed from the study, to reach our goal enrollment based on our power analysis.
Randomization and Blinding
Patients were randomized by our institutional Investigational Drug Services (IDS) using a computer-generated block randomization scheme to one of two groups: bilateral PIFB and RSB with local anesthetic (experimental group) or bilateral PIFB with local anesthetic and bilateral RSB with saline (placebo group). IDS prepared study drugs; clinical care teams, data collectors, and patients were blinded to group allocation.
Procedures
Following the informed consent process on the day of surgery, a member of the study team instructed each enrolled patient on how to use a 4,000mL volumetric incentive spirometer (Airlife,™ Vyaire Medical, Mettawa, IL). The team member recorded each patient’s best three inspiratory volumes (mL) to identify their average preoperative baseline inspiratory capacity.
Intraoperative care was at discretion of the cardiac anesthesia team with the following exceptions: fentanyl and sufentanil were the only opioids used, with fentanyl administration limited to bolus dosing, rather than infusions. Sufentanil infusions were limited to 0.2–0.5 mcg/kg/hr and were stopped prior to or upon arrival in the intensive care unit (ICU). Anesthesia teams were asked to ensure neuromuscular blockade reversal.
Nerve blocks were performed by an experienced regional anesthesiologist or an anesthesia trainee supervised by a regional anesthesiologist and occurred at the end of surgery following surgical skin closure, with the patient under general anesthesia with all standard ASA monitors in place.
Following nerve blocks, all patients were transferred to the ICU. The timing of extubation was at the discretion of the cardiac anesthesia and/or ICU team.
Postoperative care was at the discretion of the ICU team. Multimodal analgesia was administered per institutional standard of care, which includes scheduled acetaminophen, scheduled ketorolac and/or ibuprofen if no contraindications, methocarbamol as needed, and dexmedetomidine if needed for sedation prior to extubation. Multimodal administration in the first 48 hours after anesthesia stop was examined as a potential confounding variable. Opioids were administered via provider orders, typically “as needed” based on patient-reported pain.
Safety Monitoring
Patients were evaluated on postoperative day one by the regional anesthesia service for potential block-related adverse events (AE) (hematoma, infection, local anesthetic toxicity, or damage to nearby structures), and the study team monitored patient charts to assess for other AEs later during hospitalization. Potential AEs were reviewed by the clinical care team and the study’s independent monitor and reported to the IRB as required. An emergency unblinding provision was included in the study protocol.
Single Injection Bilateral PIFB
The ultrasound-guided PIFBs (see Figure 1a) were performed as described by Khera at al13: a linear high frequency ultrasound probe was placed in a parasagittal orientation between the third and fourth ribs, lateral to the sternal border, and relevant structures were identified. An 8 cm 22 gauge insulated block needle (Sonoplex, Pajunk Medical Systems, Norcross, GA) was inserted in-plane between the internal intercostal and pectoralis major muscles. Once satisfactory needle tip position was confirmed, 15 mL of 0.25% bupivacaine with epinephrine 5 mcg/ml was injected with intermittent aspiration. This procedure was repeated on the contralateral side.
Figure 1.
Ultrasound image of pectointercostal fascial plane block and rectus sheath blocks
Single Injection Bilateral High RSB
The ultrasound-guided RSBs (see Figure 1b) were performed as described by Grant and Auyong.17 A linear high frequency ultrasound probe was placed in a transverse position in the midline, just inferior to the sternum. The probe was moved laterally to visualize the rectus abdominis muscle. After identification of pertinent structures, an 8 cm 22 gauge insulated block needle (Sonoplex, Pajunk Medical Systems, Norcross, GA) was inserted in-plane deep to the rectus abdominis and superficial to the posterior fascia. After negative aspiration, 10 mL of study drug was injected into the plane. Study drug was either 0.9% normal saline (placebo) or 0.25% bupivacaine with epinephrine 5mcg/mL (experimental). This procedure was repeated on the contralateral side.
Outcomes:
The primary outcome was area under the curve (AUC) for pain at rest and with deep breathing within the first 24 hours post-extubation. ICU nurses recorded pain scores from 0–10 on a numeric rating scale (NRS) at 1, 3, 6, 12, 18, and 24 hours post-extubation, and AUC was derived from these values using a simple trapezoidal rule. AUC was on a scale of 0–240, with higher representing more pain.
Secondary outcomes included total opioid consumption at 24 and 48 hours postoperatively, change from baseline on incentive spirometry (IS) at 1, 3, 12, and 24 hours post-extubation, time from ICU arrival to extubation, ICU and hospital length of stay, and Quality of Recovery-15 score (QoR-15)18 24 hours after extubation. QOR-15 scores range from 0–150, with higher scores correlating to a more favorable recovery experience.
To assess for confounding variables, data was also collected on intraoperative oral morphine equivalents (OMEs), non-opioid analgesics administered within the first 48 hours after anesthesia stop, surgical factors, and major patient comorbidities.
Data Analysis
Since we had no pilot data on area under the curve (AUC) pain outcomes, for our power analysis we considered a conservative scenario in which the two outcomes were uncorrelated and described detectible differences between study outcomes in terms of standard deviations (SDs). To evaluate power properties of the Hotelling T2 at ALPHA = 5% test, we considered statistical power of two two-sample t-tests at ALPHA = 2.5%. At 29 patients per group, the detectible difference at 80% power difference between group means = 0.8 SDs (ALPHA = 2.5%); and Mann-Whitney nonparametric alternative will have the same power properties at 30 patients per group. Therefore, we aimed to recruit 60 patients, with 30 in each group.
Descriptive statistics were used to present baseline characteristics of the patients in each group. The Shapiro-Wilk test was used to assess the normality of continuous primary outcome variables. Given the normality of the primary outcome data, pre-planned Hotelling T-tests was used to compare AUC measures between groups. For all secondary outcomes, either Mann-Whitney or Wilcoxon Rank-Sum tests were used. Statistical significance was defined as p< 0.05.
Statistical analysis was performed using R version 4.4.2 (R Core Team).19
Data Management
Study data were collected and managed using REDCap (Research Electronic Data Capture) electronic data capture tools hosted at the Medical College of Wisconsin.20,21
RESULTS
Patient Characteristics
One hundred and sixty-seven patients undergoing cardiac surgery were screened, and 62 patients were enrolled in the study, as seen in Figure 2. Twelve patients were screened via medical record review but were unable to be contacted via phone; 21 patients declined; 79 met exclusion criteria; and one patient met inclusion criteria but was unable to be fully enrolled and randomized due to an isolated systems issue preventing IDS from preparing the study drug. Patient characteristics are shown in Table 1. There were no differences between the experimental and placebo groups with respect to age, BMI, gender, major comorbidities, or surgical characteristics between groups. Additionally, as seen in Table 2, there was no difference in intraoperative OMEs or administration of multimodal agents between groups.
Figure 2. CONSORT 2025 Flow Diagram.
** Systems issue prevented investigational drug services from preparation of study drug
*** Two patients were removed from the study post-block due to post-operative complications (acute right heart failure requiring RVAD, major surgical bleeding) unrelated to nerve blocks which prevented subsequent data collection.
Table 1.
Patient and Surgical Characteristics
| Overall N=60 | Placebo (PIFB + Saline RSB) | Intervention (PIFB + Bupivacaine RSB) | P value a | |
|---|---|---|---|---|
| Demographics | ||||
| Sex, n (%) | 0.8 | |||
| Male | 43 (72) | 21 (70) | 22 (73) | |
| Female | 17 (28) | 9 (30) | 8 (27) | |
| Age, mean (SD) | 67.42 (9.08) | 67.3 (8.79) | 67.5 (9.51) | 0.9 |
| BMI, kg/m2 (SD) | 29.82 (5.36) | 30.8 (6.17) | 28.9 (4.31) | 0.3 |
| Comorbidities | ||||
| Hypertension, n (%) | 41 (68.3) | 21 (72.4) | 20 (71.4) | 0.8 |
| Diabetes, n (%) | 15 (25) | 7 (24.1) | 8 (28.6) | 0.8 |
| CAD, n (%) | 48 (80) | 25 (86.2) | 23 (82.1) | 0.5 |
| PVD, n (%) | 6 (10) | 3 (10.3) | 3 (10.7) | >0.9 |
| Neuropathy, n (%) | 6 (10) | 4 (13.8) | 2 (7.1) | 0.7 |
| Anxiety, n (%) | 7 (11.7) | 5 (17.2) | 2 (7.1) | 0.4 |
| Depression, n (%) | 9 (15) | 5 (17.2) | 4 (14.3) | >0.9 |
| CVA, n (%) | 4 (8.3) | 1 (3.4) | 3 (10) | 0.6 |
| CKD/ESRD, n (%) | 9 (16.7) | 4 (13.8) | 5 (21.5) | >0.9 |
| COPD, n (%) | 1 (1.7) | 1 (3.4) | 0 (0) | >0.9 |
| Surgical Procedure | 0.8 | |||
| CABG, n (%) | 38 (63) | 20 (67) | 18 (60) | |
| Number of grafts: | ||||
| One, n (%) | 1 (1.2) | 1 (5) | 0 (0) | |
| Two, n (%) | 8 (13.3) | 6 (30) | 2 (11) | |
| Three, n (%) | 20 (33.3) | 9 (45) | 11 (61) | |
| Four, n (%) | 9 (15) | 4 (20) | 5 (28) | |
| CABG + single valve, n (%) | 6 (10) | 3 (10) | 3 (10) | |
| Single valve (n (%) | 16 (26.7) | 7 (23) | 9 (30) | |
| Average Aortic crossclamp time (hours) mean (SD) | 1.38 (0.57) | 1.32 (0.59) | 1.47 (0.53) | 0.2 |
| Average Cardiopulmonary bypass time (hours) mean (SD) | 1.78 (0.68) | 1.78 (0.73) | 1.85 (0.62) | 0.5 |
| Average Total surgical time (hours) mean (SD) | 4.73 (1.21) | 4.6 (1.3) | 4.88 (1.15) | 0.4 |
Wilcoxon rank sum test; Pearson’s Chi-squared test; Wilcoxon rank sum exact test
Table 2.
Analgesic administration between groups
| Placebo (PIFB + Saline RSB) a | Intervention (PIFB + Bupivacaine RSB)a | P value b | |
|---|---|---|---|
| Total intraoperative OME (mg) | 276.64 (102.9) | 297.44 (65.13) | 0.8 |
| Average doses of postoperative medications given in first 48 hours from anesthesia stop: | |||
| Ibuprofen (mg) | 400 (0/800) | 0 (0/800) | 0.83 |
| Ketorolac (mg) | 22.5 (0/60) | 30 (0/60) | 0.99 |
| APAP (mg) | 5550 (4975/66588) | 5550 (4975/6200) | 0.56 |
| Methocarbamol (mg) | 1000 (750/1438) | 1000 (500/1750) | 0.88 |
| Dexmedetomidine (mcg) | 0 (0/13.96) | 0 (0/0) | 0.44 |
Mean (SD) or Median (1st/3rd quartiles) unless otherwise noted
Wilcoxon rank sum test; Pearson’s Chi-squared test; Wilcoxon rank sum exact test
Primary Outcome
Mean AUC for pain at rest in the first 24 hours postoperatively for patients in the placebo group was 93.37 +/− 41.38 versus 86.11 +/− 42.78 in the bupivacaine group (p=0.51). Mean AUC for pain with deep breathing in the first 24 hours postoperatively for patients in the placebo group was 135.55 +/− 43.74 versus 128.78 +/− 47.08 in the bupivacaine group (p=0.57). Hotelling T2 test comparing the pain at rest and pain with deep breathing between the placebo and intervention groups showed no statistically significant difference (p=0.8). As there was no difference in AUC, an exploratory analysis was performed to examine pain at one hour post-extubation between groups, a time when the blocks would likely be expected to be in effect, and there was no statistical difference between mean pain on a NRS in the placebo and bupivacaine groups either at rest or with deep breathing, as seen in Table 3.
Table 3.
Primary and Secondary Outcomes
| Overall N=60a | Placebo (PIFB + Saline RSB) | PIFB + Bupivacaine RSB | P valueb | |
|---|---|---|---|---|
| Outcomes | ||||
| Pain at rest in the first 24h (AUC) | 89.25 (60.90,117.75) | 102.00 (65.00,120.00) | 79.25 (60.00,117.00) | 0.4 |
| Pain with deep breathing in the first 24h (AUC) | 142.25 (94.50,159.75) | 144.00 (90.00,160.00) | 141.50 (97.00,159.50) | 0.8 |
| Average pain scores at rest at one hour (0–10) | 4.33 (2.74) | 4.63 (2.91) | 4.03 (2.58) | 0.6 |
| Average pain scores with deep breathing at one hour (0–10) | 5.72 (2.85) | 6.15 (2.68) | 5.28 (2.99) | 0.3 |
| Cumulative Opioid Consumption at 24 Hours postop (OME) | 58.75 (42.50,95.00) | 58.75 (42.50,91.50) | 55.25 (42.50,97.50) | >0.9 |
| Cumulative Opioid Consumption at 48 Hours postop (OME) | 95.00 (56.25,137.63) | 95.00 (55.00,130.25) | 96.75 (57.50,145.00) | 0.8 |
| Duration of Intubation (hours) | 3.87 (2.31,4.81) | 3.87 (2.63,4.80) | 3.87 (2.08,4.82) | >0.9 |
| Time to ICU Discharge (hours) | 23.56 (18.03,44.89) | 25.77 (22.28,45.22) | 20.69 (17.63,37.23) | 0.11 |
| Time to Hospital discharge (hours) | 97.21 (91.53,121.94) | 97.31 (93.71, 120.78) | 97.21 (89.16, 135.89) | >0.9 |
| Quality of Recovery (QoR-15) Score | 83.00 (67.00,101.00) | 79.50 (63.00,94.00) | 83.00 (70.00,106.00) | 0.5 |
| Preoperative IS (mL) | 2911.11 (870.38) | 2943.89 (905.5) | 2878.33 (847.99) | 0.7 |
| Percent change from baseline on IS at 1 hour | 0.24 (0.18,0.34) | 0.24 (0.18,0.46) | 0.25 (0.17,0.29) | 0.4 |
| (Missing) | 7 | 3 | 4 | |
| Percent change from baseline on IS at 3 hours | 0.27 (0.22,0.38) | 0.29 (0.22,0.41) | 0.26 (0.22,0.36) | 0.4 |
| Percent change from baseline on IS at 12 hours | 0.32 (0.24,0.43) | 0.33 (0.28,0.48) | 0.28 (0.21,0.37) | 0.045 |
| (Missing) | 3 | 1 | 2 | |
| Percent change from baseline on IS at 24 hours | 0.32 (0.26,0.45) | 0.30 (0.26,0.45) | 0.32 (0.26,0.45) | 0.9 |
| (Missing) | 7 | 3 | 4 |
Mean (Standard Deviation), Median (Q1, Q3) or Frequency (%)
Wilcoxon rank sum test; Fisher’s exact test
Unless otherwise noted, all times measured from anesthesia stop.
Of note, 3/840 possible pain scores were not gathered, and linear interpolation was used to estimate and include these values in the analysis.
Secondary Outcomes
Total opioid consumption (OME(IQR)) at 24 hours postoperatively was 58.75 (43.1, 90.6) in the placebo group and 55.25 (42.5, 96.9) in the bupivacaine group (p=0.98), visible in Table 3. Total opioid consumption (OME(IQR)) at 48 hours postoperatively was 95 (56.2, 130.2) in the placebo group versus 96.75 (58.12, 141.25) in the bupivacaine group (p=0.84).
There was no difference in change from baseline in IS between groups in time intervals following extubation. At one hour, median IS performance was 24 (18, 46) percent of baseline in the placebo versus 25 (17, 29) percent of baseline in the bupivacaine group (p=0.4); at three hours performance was 29 (22, 41) percent of baseline in the placebo versus 26 (22, 36) percent of baseline in the bupivacaine group (p=0.4); at 12 hours, performance was 33 (28, 48) percent of baseline in the placebo versus 28 (21, 37) percent of baseline in the bupivacaine group (p=0.05); and at 24 hours, performance was 30 (26, 45) percent of baseline in the placebo versus 32 (26, 45) percent of baseline in the bupivacaine group (p=0.9). Of note, there were 17 missing IS scores out of 300 total possible scores. Two of these were for patients in the placebo group who required bilevel positive airway pressure support post-extubation. These and other missing IS scores (for unknown reasons) were left out of analysis, and the number of missing variables is noted in Table 3.
Median time (hours (IQR)) from ICU arrival to extubation was 3.87 (2.683, 4.787) in the placebo group and 3.87 (2.13, 4.76) in the bupivacaine group (p=0.98). Median ICU length of stay (hours (IQR) was 25.77 (22.4, 45.05) in the placebo group versus 20.69 (17.64, 36.79) in the bupivacaine group (p=0.11). Median hospital length of stay (hours, IQR) was 97.31 (93.71, 120.78) in the placebo group versus 97.21 (89.16, 135.89) in the bupivacaine group (p=0.94).
The total median score on the QoR-1523 24 hours after extubation was 79.5 (64, 93.75) in the placebo group versus 83 (70, 106) in the bupivacaine group (p=0.51).
No patients experienced study-related adverse events.
DISCUSSION
In this single-center, prospective, double-blinded, placebo-controlled study, performing RSB with PIFB did not confer additional benefit beyond PIFB alone in cardiac surgery involving primary median sternotomy. There was no statistical difference in pain scores at rest or with deep breathing in the first 24 hours between groups, no significant difference in pain between groups at one hour after extubation, and importantly, there was also no difference in relevant clinical outcomes, such as opioid usage, time to extubation, or patient-reported quality of recovery.
The epigastric chest tube insertion site has been identified as a significant pain source for cardiac surgery patients; in one study of 160 patients who underwent cardiac surgery with median sternotomy and subxiphoid drain placement, the epigastric area was the second most painful area through POD 3, superseded only by the central chest.10 Pain at this site would likely be somatic, caused by friction against skin and muscle, which should be covered by a RSB.22 The lack of efficacy of RSB in this study could potentially be explained by characteristics of the block itself, other elements of the analgesic regimen, or perhaps by variations of pain experience in different populations.
For example, our block characteristics varied slightly from those chosen by the two prior RCTs on this topic. In the study by Wang et al,16 54 patients undergoing cardiac surgery were randomized to receive bilateral pre-surgical incision PIFB along with either placebo (saline) or RSB with 15mL on each side of 0.3% ropivacaine with 2.5mg dexamethasone. This study was double-blinded, with a standardized postoperative multimodal regimen with hydromorphone via patient-controlled intravenous analgesia (PCA). The PIFB+RSB group had lower IV hydromorphone consumption than the PIFB + placebo group at 24 (2.33 versus 3.81mg, p=0.01) and 48 hours (4.71 versus 7.25mg, p=0.01).
In a second study led by Strumia et al,15 58 cardiac surgery patients were randomized to pre-incision bilateral PIFB with 20mL of 0.5% ropivacaine with 1mg dexamethasone on each side, along with either preoperative bilateral RSB or end-of-case surgeon infiltration of the chest tube site using a total of 20mL of 0.25% ropivacaine. The group found a difference in their primary outcome, pain at rest at extubation, with pain 4/10 in the RSB group versus 5/10 in the infiltration group (p=0.03).
Compared to our study, both Wang and Strumia’s groups used higher volumes of more concentrated local anesthetic, which may explain the more effective opioid reduction. Our group was conservative with local anesthetic dosing given the risk of arrhythmias and hemodynamic instability in cardiac surgical patients. However, perhaps a higher volume of more concentrated anesthetic would have contributed to a more effective block. Additionally, the adjuvant dexamethasone may explain effects such as Wang’s opioid reduction up to 48 hours, which is longer than anticipated with ropivacaine and important, as a separate study tracking pain in cardiac surgery patients demonstrated that the epigastric site pain did not peak until POD 2.23 This raises the question of whether catheters would have more efficacy than single-shot blocks – although in this study (as in others), the median sternotomy site was the primary driver of pain, and arguably a more worthy target of catheters than the epigastric site.
Additionally, as both Strumia and Wang utilized preoperative blocks, the question arises of whether the timing of RSB affects outcomes. Although our group chose a postoperative block time to optimize duration, a tactic that has proven beneficial in some abdominal fascial plane block studies, 24 we question whether the preoperative block timing created more effective local spread prior to disruption of tissue planes or perhaps through mechanisms suggested by proponents of preemptive analgesia, in which analgesia provided before a painful stimulus is thought to minimize pain signaling, decreasing peripheral and central sensitization.25 Some studies have shown benefit of preemptive analgesia in the form of epidurals for thoracic surgery26 or brachial plexus blocks before orthopedic procedures,27 but data from timing of abdominal fascial plane blocks has not shown similar benefit to date.24,28–29 Future research is needed to more clearly examine optimal block timing.
Last, our institutional multimodal regimen frequently included a muscle relaxant, methocarbamol, which was not used by the Strumia or Wang groups. We question whether the addition of a muscle relaxant helped explain our study’s lack of significant differences between groups, as RSB can itself cause muscle relaxation.30
One caveat of the comparison of our study to prior studies is that while both Wang and Strumia had statistically significant differences in groups, the clinical efficacy of the blocks was still questionable. Wang’s group found no difference in any other outcome, including pain scores, time to extubation, ICU or hospital length of stay, incidence of chronic pain, serum inflammatory markers, or opioid-related adverse outcomes. Strumia’s reduction in pain scores from 5 to 4/10 is arguably not very clinically significant, and many of their other effect sizes were small, such as a reduction in median morphine consumption in the first 24 hours (0 versus 2mg, p<0.01). It may be that the epigastric chest tube site is not as significant a driver of pain in all populations as it was in Mueller’s study. In the Totonchi study, the epigastric site was just one of multiple less painful sites than the medial and left chest,23 so for some populations, perhaps even an ideal RSB will not make a large difference in overall pain control and outcomes.
This study had limitations. While our patient number was comparable to similar studies, we may have been underpowered to detect a difference given the small effect sizes seen. However, the fact that the effect sizes were small is itself important information. The testing the null hypothesis continues to be valid: we still control type 1 error at 5% for the primary hypothesis. Next, there was a small number of missing data points due to competing clinical demands in the ICU or patients who declined to perform IS, and it is possible that the absent data could have altered outcomes. Also, our study did not standardize intraoperative anesthetic management, so while intraoperative opioids were controlled, there may have been other sedating agents administered that affected outcomes. However, we feel that we tested our intervention in the setting of typical, real-world anesthesia practice and did not find significant benefits, which is valuable information. Similarly, we allowed our ICU to treat patients’ pain per their standard of care without any additional education for nurses or patients on opioid administration. This introduces a theoretical risk that opioid administration was influenced by practice habits, so perhaps a PCA with patient education could have provided a more sensitive indicator of patient opioid requirement. Finally, our patient sample was racially homogeneous and therefore our results may not be generalizable to all populations.
Conclusions:
In this single-center, randomized, placebo-controlled trial, RSB did not improve postoperative pain or outcomes in addition to PIFB for patients undergoing cardiac surgery involving median sternotomy and mediastinal chest tubes. Future research could focus on optimal block dosing and timing; however, taken with the small clinical effect sizes in prior studies, RSB for subxiphoid chest tube sites may not be a high-yield component of post-cardiac surgical analgesia.
Supplementary Material
Key messages.
What is already known on this topic:
Bilateral pecto-intercostal fascial plane blocks improve pain following cardiac surgery with median sternotomy, but data has been mixed on whether the addition of a rectus sheath block for pain at the subxiphoid chest tube insertion sites provides clinically meaningful improvement in pain or other outcomes.
What this study adds.
In this study, the addition of bilateral rectus sheath block did not improve postoperative pain or outcomes in addition to pecto-intercostal block for patients undergoing cardiac surgery involving primary median sternotomy with mediastinal chest tubes.
How this study might affect research, practice, or policy.
Given the lack of significant effect in this study and small clinical effect sizes in prior studies, rectus sheath block for subxiphoid chest tube sites may not be a high-yield addition to pain control after cardiac surgery in the setting of a robust multimodal analgesic plan.
ACKNOWLEDGEMENTS:
We would like to thank the Froedtert Cardiothoracic Surgery, Cardiac Anesthesia, and Regional Anesthesia Divisions for their collaboration in this study; the Cardiovascular Intensive Care Unit and Cardiac Stepdown unit nursing leadership and teams for all their contributions to data collection; and our independent monitor, Dr. Craig Cummings.
Funding:
This publication was supported by the National Center for Advancing Translational Sciences, National Institutions of Health, through Grant Number UL1 TR001436. Its contents are solely the responsibility of the authors and do not necessarily represent the official views of the NIH.
Abbreviations:
- PIFB
Pecto-intercostal Fascial Plane Block
- RSB
Rectus Sheath Block
- FPB
Fascial plane blocks
- OME
Oral morphine equivalents
- AUC
Area Under the Curve
- FPB
Fascial Plane Block
- CABG
Coronary Artery Bypass Grafting
- IDS
Investigational Drug Services
- ICU
Intensive Care Unit
- REDCap
Research Electronic Data Capture
- AE
Adverse Events
Footnotes
Conflicts of Interest:
The authors declare no conflicts of interest.
REFERENCES:
- 1.Lahtinen P, Kokki H & Hynynen M Pain after cardiac surgery: a prospective cohort study of 1-year incidence and intensity. Anesthesiology. 2006; 105:794–800. doi: 10.1097/00000542-200610000-00026. [DOI] [PubMed] [Google Scholar]
- 2.Craig D Postoperative Recovery of Pulmonary Function. Anesthesia and Analgesia. 1981;60(1): 46–52. [PubMed] [Google Scholar]
- 3.Janssen-Sanders Ll GL, Bruins P, Driessen A, Morshuis W, Knibbe C, Dongen EV. Pain in intensive care after sternotomy is predictive for chronic thoracic pain. Critical Care. 2008(12):1510. doi: 10.1186/cc6731. [DOI] [Google Scholar]
- 4.Costa MA, Trentini CA, Schafranski MD, Pipino O, Gomes RZ, Reis ES. Factors Associated with the Development of Chronic Post-Sternotomy Pain: a Case-Control Study. Braz J Cardiovasc Surg. 2015;30(5):552–6. doi: 10.5935/1678-9741.20150059. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 5.Engelman D BAW, Williams J, Perrault L, Reddy V, Arora R, Roselli E, Khoynezhad A, Gerdisch M, Levy J, Lobdell K, Fletcher N, Kirsch M, Nelson G, Engelman R, Gregory A, Boyle E. Guidelines for Perioperative Care in Cardiac Surgery Enhanced Recovery After Surgery Society Recommendations. JAMA Surgery. 2019;15: 755–766. doi: 10.1001/jamasurg.2019.1153. [DOI] [PubMed] [Google Scholar]
- 6.Grant MC, Crisafi C, Alvarez A, Arora RC, Brindle ME, Chatterjee S, Ender J, Fletcher N, Gregory AJ, Gunaydin S, Jahangiri M, Ljungqvist O, Lobdell KW, Morton V, Reddy VS, Salenger R, Sander M, Zarbock A, Engelman DT. Perioperative Care in Cardiac Surgery: A Joint Consensus Statement by the Enhanced Recovery After Surgery (ERAS) Cardiac Society, ERAS International Society, and The Society of Thoracic Surgeons (STS). Ann Thorac Surg. 2024. Apr;117(4):669–689. doi: 10.1016/j.athoracsur.2023.12.006. [DOI] [PubMed] [Google Scholar]
- 7.Schmedt J, Oostvogels L, Meyer-Frießem CH, Weibel S, Schnabel A. Peripheral Regional Anesthetic Techniques in Cardiac Surgery: A Systematic Review and Meta-Analysis. J Cardiothorac Vasc Anesth. 2024. Feb;38(2):403–416. doi: 10.1053/j.jvca.2023.09.043. [DOI] [PubMed] [Google Scholar]
- 8.McDonald S JE, Kopacz D, Desphande S, Helman J, Salinas, Hall R. Parasternal Block and Local Anesthetic Infiltration with Levobupivacaine After Cardiac Surgery with Desflurane: The Effect on Postoperative Pain, Pulmonary Function, and Tracheal Extubation Times. Anesthesia and Analgesia. 2005;100:25–32. doi: 10.1213/01.ANE.0000139652.84897.BD. [DOI] [PubMed] [Google Scholar]
- 9.Fujii S, Roche M, Jones PM, Vissa D, Bainbridge D, Zhou JR. Transversus thoracis muscle plane block in cardiac surgery: a pilot feasibility study. Reg Anesth Pain Med. 2019;44(5):556–560. doi: 10.1136/rapm-2018-100178. [DOI] [PubMed] [Google Scholar]
- 10.Mueller XM, Tinguely F, Tevaearai HT, Ravussin P, Stumpe F, von Segesser LK. Impact of duration of chest tube drainage on pain after cardiac surgery. Eur J Cardiothorac Surg. 2000. Nov;18(5):570–4. doi: 10.1016/s1010-7940(00)00515-7. [DOI] [PubMed] [Google Scholar]
- 11.de la Torre PA, García PD, Alvarez SL, Miguel FJ, Pérez MF. A novel ultrasound-guided block: a promising alternative for breast analgesia. Aesthet Surg J. 2014;34(1):198–200. doi: 10.1177/1090820X13515902. [DOI] [PubMed] [Google Scholar]
- 12.Khera T, Murugappan K, Leibowitz A, Bareli N, Shankar P, Gilleland A, Wilson K, Oren-Grinberg A, Novack V, Venkatachalam S, Rangasamy V, Subramaniam B. Ultrasound-Guided Pecto-Intercostal Fascial Block for Postoperative Pain Management in Cardiac Surgery: A Prospective, Randomized, Placebo-Controlled Trial. J Cardiothorac Vasc Anesth. 2021;35(3):896–903. [DOI] [PubMed] [Google Scholar]
- 13.Sepolvere G, Tedesco M, Fusco P, Scimia P, Donatiello V, Cristiano L. Subxiphoid cardiac drainage pain management: could ultrasound rectus sheath block be the answer? Minerva Anestesiol. 2020;86(9):994–996. doi: 10.23736/S0375-9393.20.14576-0. [DOI] [PubMed] [Google Scholar]
- 14.Strumia A, Pascarella G, Sarubbi D, Di Pumpo A, Costa F, Conti MC, Rizzo S, Stifano M, Mortini L, Cassibba A, Schiavoni L, Mattei A, Ruggiero A, Agrò FE, Carassiti M, Cataldo R. Rectus sheath block added to parasternal block may improve postoperative pain control and respiratory performance after cardiac surgery: a superiority single-blinded randomized controlled clinical trial. Reg Anesth Pain Med. 2024. Jun 14:rapm-2024–105430. doi: 10.1136/rapm-2024-105430. [DOI] [PubMed] [Google Scholar]
- 15.Wang L, Jiang L, Jiang B, Xin L, He M, Yang W, Zhao Z, Feng Y. Effects of pecto-intercostal fascial block combined with rectus sheath block for postoperative pain management after cardiac surgery: a randomized controlled trial. BMC Anesthesiol. 2023;23(1):90. doi: 10.1186/s12871-023-02044-w. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 16.ClinicalTrials.gov [Internet]. Bethesda (MD): National Library of Medicine (US). NCT04908449, Pectointercostal Fascial Plane Block (PIFB) Alone Versus PIFB With Rectus Sheath Block (RSB) in Cardiac Surgery; 2021. May 24 [cited 2025 Aug 26]. Available from: https://clinicaltrials.gov/study/NCT04908449. [Google Scholar]
- 17.Grant S AD Ultrasound Guided Regional Anesthesia. Second Ed. Oxford University Press: 2017. [Google Scholar]
- 18.Kleif J, Waage J, Christensen KB, Gögenur I. Systematic review of the QoR-15 score, a patient-reported outcome measure measuring quality of recovery after surgery and anaesthesia. Br J Anaesth. 2018;120(1):28–36. doi: 10.1016/j.bja.2017.11.013. [DOI] [PubMed] [Google Scholar]
- 19.R Core Team (2024). _R: A Language and Environment for Statistical Computing_. R Foundation for Statistical Computing, Vienna, Austria. https://www.R-project.org/. [Google Scholar]
- 20.Harris PA, Taylor R, Thielke R, Payne J, Gonzalez N, Conde JG, Research electronic data capture (REDCap) – A metadata-driven methodology and workflow process for providing translational research informatics support, J Biomed Inform. 2009;42(2):377–81. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 21.Harris PA, Taylor R, Minor BL, Elliott V, Fernandez M, O’Neal L, McLeod L, Delacqua G, Delacqua F, Kirby J, Duda SN, REDCap Consortium, The REDCap consortium: Building an international community of software partners, J Biomed Inform. 2019. May 9. [doi: 10.1016/j.jbi.2019.103208] [DOI] [PMC free article] [PubMed] [Google Scholar]
- 22.Chin KJ, McDonnell JG, Carvalho B, Sharkey A, Pawa A, Gadsden J. Essentials of Our Current Understanding: Abdominal Wall Blocks. Reg Anesth Pain Med. 2017;42(2):133–183. doi: 10.1097/AAP.0000000000000545. [DOI] [PubMed] [Google Scholar]
- 23.Totonchi Z, Seifi S, Chitsazan M, Alizadeh Ghavidel A, Baazm F, Faritus SZ. Pain location and intensity during the first week following coronary artery bypass graft surgery. Anesth Pain Med. 20134(1):e10386. doi: 10.5812/aapm.10386. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 24.Rahimzadeh P, Faiz SHR, Latifi-Naibin K, Alimian M. A Comparison of effect of preemptive versus postoperative use of ultrasound-guided bilateral transversus abdominus plane (TAP) block on pain relief after laparoscopic cholecystectomy. Sci Rep. 2022;2:12(1):623. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 25.Kamel MK. Commentary: Role of pre-emptive analgesia in reversing the opioid epidemic. J Thorac Cardiovasc Surg. 2020;159(2):745–746. doi: 10.1016/j.jtcvs.2019.10.181. [DOI] [PubMed] [Google Scholar]
- 26.Park SK, Yoon S, Kim BR, Choe SH, Bahk JH, Seo JH. Pre-emptive epidural analgesia for acute and chronic post-thoracotomy pain in adults: a systematic review and meta-analysis. Reg Anesth Pain Med. 2020;45(12):1006–1016. doi: 10.1136/rapm-2020-101708. [DOI] [PubMed] [Google Scholar]
- 27.Holmberg A, Sauter AR, Klaastad Ø, Draegni T, Raeder JC. Pre-operative brachial plexus block compared with an identical block performed at the end of surgery: a prospective, double-blind, randomised clinical trial. Anaesthesia. 2017;72(8):967–977. doi: 10.1111/anae.13939. [DOI] [PubMed] [Google Scholar]
- 28.Xia J, Paul Olson TJ, Tritt S, Liu Y, Rosen SA. Comparison of preoperative versus postoperative transversus abdominis plane and rectus sheath block in patients undergoing minimally invasive colorectal surgery. Colorectal Dis. 2020;22(5):569–580. doi: 10.1111/codi.14910. [DOI] [PubMed] [Google Scholar]
- 29.Chang-Patel EJ, Wong JMK, Gould CH, Demirel S. The Effect of Transversus Abdominis Plane Block Timing on Milliequivalents of Opioid Use and Immediate Postoperative Pain Scores in Patients Undergoing Minimally Invasive Hysterectomy: A Retrospective Cohort Study. J Minim Invasive Gynecol. 2024;31(3):237–242. doi: 10.1016/j.jmig.2023.12.013. [DOI] [PubMed] [Google Scholar]
- 30.May PL, Wojcikiewicz T. Regional anaesthesia and fascial plane blocks for abdominal surgery: a narrative review. Dig Med Res. 2022;5:2617–1627. [Google Scholar]
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