Programmed Intermittent Bolus versus Continuous Infusion for Catheter-Based Erector Spinae Plane Block on Quality of Recovery in Thoracoscopic Surgery: A Single-Centre Randomised Controlled Trial

Anesthesiology Medicine
erector spinae plane block thoracoscopic surgery programmed intermittent bolus continuous infusion postoperative recovery regional anaesthesia randomised controlled trial

Background

In recent years, Video-Assisted Thoracoscopic Surgery (VATS) has gained increasing popularity as a minimally invasive technique in thoracic surgery. Compared to traditional thoracotomy, VATS offers advantages such as reduced postoperative pain, shorter recovery times, decreased hospital stays, and better preservation of pulmonary function. However, despite the minimally invasive nature of VATS, acute postoperative pain and recovery issues remain prevalent, particularly within the first 24 hours post-surgery. To alleviate postoperative pain, regional anesthesia techniques, such as the Erector Spinae Plane Block (ESP Block), have emerged as important tools for postoperative analgesia in VATS.

The ESP block works by injecting local anesthetics into the fascial plane of the erector spinae muscle, thereby blocking pain signal transmission and reducing postoperative pain. However, the duration of analgesia from a single-shot ESP block is limited. As a result, continuous catheter infusion of local anesthetics has become a common method for postoperative pain management. In recent years, Programmed Intermittent Bolus (PIB) has been proposed as a novel delivery method, potentially enhancing the spread of local anesthetics within the fascial plane through intermittent bolus injections, thereby improving analgesic efficacy. However, there is limited data comparing the effectiveness of PIB versus Continuous Infusion (CI) in ESP blocks, particularly studies focusing on patient-centered recovery quality as the primary endpoint.

Therefore, this study aimed to compare the effects of PIB and CI in ESP block analgesia following VATS, with a particular focus on the quality of recovery at 24 hours post-surgery, through a single-center, randomized, double-blind controlled trial.

Source of the Paper

This paper was co-authored by Aisling Ni Eochagain, Aneurin Moorthy, John Shaker, and others, affiliated with Mater Misericordiae University Hospital in Dublin, Ireland; the Europeriscope group of the European Society of Anaesthesiology and Intensive Care (ESAIC); the School of Medicine at University College Dublin; and the Outcomes Research Department at the Cleveland Clinic in the USA. The paper was published on July 29, 2024, in the British Journal of Anaesthesia, with the DOI: 10.1016/j.bja.2024.05.041.

Study Design

1. Study Design and Inclusion Criteria

This was a single-center, randomized, double-blind controlled trial designed to compare the effects of PIB and CI in ESP block analgesia following VATS. A total of 60 patients undergoing VATS were enrolled. All patients received ultrasound-guided ESP catheter placement after induction of general anesthesia. Patients were randomly assigned to either the PIB or CI group, receiving different local anesthetic infusion regimens.

Inclusion Criteria:

  • Age ≥18 years, weight ≥55 kg;
  • Ability to provide written informed consent;
  • American Society of Anesthesiologists (ASA) physical status of 1, 2, or 3;
  • Scheduled for VATS.

Exclusion Criteria:

  • Infection at the block site;
  • Severe coagulopathy;
  • Allergy to local anesthetics;
  • History of opioid abuse;
  • Chronic pain or dementia;
  • Postoperative ICU admission for mechanical ventilation;
  • Body Mass Index (BMI) >40 kg/m²;
  • Intraoperative conversion from VATS to open thoracotomy.

2. Study Intervention

All patients received a bolus of 20 mL of 0.25% levobupivacaine for ESP block before surgery. Postoperatively, patients were randomized to either the PIB or CI group, receiving the following local anesthetic infusion regimens:

  • PIB Group: 20 mL of 0.125% levobupivacaine every 2 hours, totaling 300 mg over 24 hours;
  • CI Group: Continuous infusion of 0.125% levobupivacaine at 10 mL/hour, totaling 300 mg over 24 hours.

3. Primary and Secondary Outcomes

Primary Outcome:

  • Quality of Recovery-15 (QoR-15) score at 24 hours post-surgery. The QoR-15 is a validated 15-item questionnaire assessing five domains of postoperative recovery: comfort, independence, pain, psychological state, and emotional state. Scores range from 0 to 150, with higher scores indicating better recovery.

Secondary Outcomes:

  • Respiratory function recovery at 24 hours (maximum inspiratory volume and percentage recovery compared to preoperative baseline);
  • Postoperative pain scores (at rest and during deep inspiration);
  • Postoperative opioid consumption;
  • Use of rescue antiemetics within 24 hours;
  • Time to first mobilization;
  • Length of hospital stay;
  • Regional anesthesia-related complications (e.g., sensory block extent, catheter dislodgement).

4. Data Analysis

Data normality was assessed using the Shapiro-Wilk and Kolmogorov-Smirnov tests. Non-normally distributed data were compared using the Mann-Whitney U test, while normally distributed data were compared using independent t-tests. Categorical data were analyzed using Fisher’s exact test. Data were presented as mean (standard deviation), median (interquartile range), or percentages, with a significance level set at p<0.05.

Results

1. Primary Outcome

There was no significant difference in QoR-15 scores at 24 hours post-surgery between the PIB and CI groups (PIB: 115.5 [107-125] vs. CI: 110 [93-128]; difference , p=0.29). The only QoR-15 parameter showing a significant difference was nausea and vomiting, with the PIB group performing better (PIB: 10 [10-10] vs. CI: 10 [7-10]; p=0.03). Additionally, the PIB group required fewer rescue antiemetics within 24 hours compared to the CI group (PIB: 4 [14%] vs. CI: 11 [41%]; p=0.04).

2. Secondary Outcomes

There were no significant differences between the groups in postoperative pain scores, opioid consumption, respiratory function recovery, time to first mobilization, or length of hospital stay. The incidence of regional anesthesia-related complications was also similar between the groups.

Conclusion

This study demonstrated that ESP block analgesia delivered via PIB or CI following VATS resulted in similar quality of recovery at 24 hours post-surgery. Although the PIB group showed slightly better performance in terms of nausea and vomiting, overall, both delivery methods provided comparable clinical efficacy for postoperative analgesia. This suggests that, in fascial plane blocks, the mode of local anesthetic delivery may be less important than the volume and dose of the anesthetic.

Highlights of the Study

  1. Patient-Centered Endpoint: This study is the first to use the patient-centered QoR-15 score as the primary endpoint to evaluate the effects of PIB versus CI in ESP blocks, emphasizing the overall patient experience of postoperative recovery.
  2. Clinical Applicability: The local anesthetic doses used in the study were within safe limits, and both delivery methods administered the same total dose, making the findings highly clinically applicable.
  3. Novelty: Although PIB is increasingly used in regional anesthesia, there is limited research on its effectiveness in ESP blocks. This study fills this gap.

Significance of the Study

This study provides new evidence for postoperative analgesia following VATS, showing that PIB and CI are similarly effective in ESP blocks. This finding allows clinicians greater flexibility in choosing postoperative analgesic regimens. Additionally, the results lay the groundwork for future multicenter, large-sample studies to further validate the value of PIB in regional anesthesia.

Other Valuable Information

The limitations of this study include its single-center design, issues with catheter dislodgement and leakage, and the short postoperative observation period (only 24 hours). Future research could address these limitations through multicenter designs, extended observation periods, and improved catheter technology to further validate the effectiveness of PIB in ESP blocks.