Abstract
Objective:
Erector spine plane block (ESPB) is a newly defined regional anesthesia technique performed by injection of local anesthetic beneath the erector spine muscle. We tested ESPB as a regional rescue analgesia bedside technique to be performed in the thoracic surgical ward, reporting a 7-patient case series.
Methods:
We report our experience in rescue analgesia after thoracic surgery. During the postoperative stay, numeric rating scale (NRS) score >3 and inability to perform physiotherapy or effective cough due to postoperative pain represented the criteria for proposing rescue analgesia with ESPB. NRS at rest and during movements was recorded; blood gas analysis and spirometry were performed to evaluate PaO2/FiO2 (P/F), forced vital capacity (FVC), and forced expiratory volume in 1 second (FEV1) before ESPB execution. After performing the ESPB, static and dynamic NRS, P/F, and FVC and FEV1 were recorded at 40 minutes and 80 minutes.
Results:
NRS had a reduction at rest and in dynamic assessment. The P/F did not improve but spirometric measures improved. FVC had a relevant improvement only after 80 minutes; FEV1 was increased after 40 minutes.
Conclusion:
The use of ESPB as postoperative rescue analgesia can offer several advantages due to effective rescue analgesia and safety that makes it easy to perform in the thoracic surgical ward or in an outpatient clinic setting.
Introduction
The pathogenesis of postoperative pain in thoracic surgery is multifactorial, depending on trauma to intercostal nerves, resection of the rib, trocar access, traction from retractors causing ischemia, and nerve entrapment or impingement from displaced rib fractures.
The importance of adequate pain management in thoracic surgical patients cannot be overstated. Apart from the ethical imperative of alleviating patients’ pain, inadequate analgesia in these patients may result in adverse clinical outcomes, such as prolonged immobilization, poor respiratory effort, and inability to cough and to remove bronchial secretions, resulting in airway closure, atelectasis, shunting, and hypoxemia, as well as the development of post-thoracotomy chronic pain. 1
Relying only on opioid analgesia in patients with marginal lung function, such as in thoracic surgery, involves a precarious balance between adequate analgesia and respiratory depression. Therefore most anesthesiologists include regional techniques in a multimodal regimen of analgesia such as thoracic epidural analgesia (TEA) and thoracic paravertebral block (TPVB).
TEA, once considered as the gold standard in case of thoracotomy, has significant associated side effects, including hypotension, respiratory depression, urinary retention, incomplete or failed block, and rarely permanent neurologic injury. 2 Moreover, due to the vertebral anatomical peculiarities of the upper thoracic tract, the TEA has a non-negligible failure rate and is considered a technique of not immediate mastery. 3
TPVB is now considered a valid alternative to TEA, with comparable pain relief, equal clinical effectiveness with regard to postoperative respiratory function, and fewer adverse effects such as hypotension. 4 Although the greater ease of execution makes it quicker to learn than TEA, the difficulty of positioning a continuous infusion catheter often limits its usefulness over time and the anatomic proximity of the pleura and neuroaxial structures make TPVB a challenging technique.
To be performed in a safe manner, TPVB requires a proper approach, in dedicated spaces and with qualified personnel; this is probably one of the reasons why this regional rescue analgesia technique is not widely used in Italy. 5
Erector spine plane block (ESPB) is a newly defined regional anesthesia technique performed by injection of local anesthetic beneath the erector spine muscle. Local anesthetic is expected to achieve paravertebral spread involving both the ventral and dorsal rami of the spinal nerves, leading to blockage of both visceral and somatic pain over the anterolateral thorax. 6
ESPB use is not widespread in thoracic surgery, probably due to the sometimes inadequate analgesia intensity owing to the lack of direct effects on the neuraxial structures.7,8 Yet ESPB is easy to perform and a relatively safe method in which the transverse process acts as an anatomic barrier and avoids needle insertion to pleura, reducing risk of pneumothorax as well as direct spinal cord injury, epidural hematoma, and central infection9–11; moreover, the safety margin could make it possible to perform in a ward or in an outpatient clinic setting. 12
We tested ESPB as a regional rescue analgesia bedside technique to be performed in the thoracic surgical ward.
Methods
All patients who underwent thoracic surgery from February to April 2019 in Monaldi Hospital (Naples, Italy) and needed rescue analgesia with ESPB were included.
Just before surgery, a single shot TPVB with ropivacaine 0.75% was performed, in a sterile manner, at T2–T3 and T5–T6, injecting 6 mL for each paravertebral block space. General anesthesia was performed with propofol and remifentanil in total IV anesthesia target-controlled infusion, using rocuronium as neuromuscular blockade and sugammadex if reversal was needed. Standard monitoring procedures included continuous ECG, noninvasive blood pressure (NIBP), peripheral oxygen saturation (SpO2), bispectral index (BIS), and train of four (TOF) measurement. At the end of surgery, patients were transferred to the postoperative intensive care unit or thoracic surgery ward according to their clinical condition. Standard postoperative antalgic therapy was acetaminophen 4 g/d and ketorolac 45 mg/d, no opioids given as first choice, and morphine given only in case of persistent pain at the dose of 20 mg until numeric rating scale (NRS) score ⩽3.
During the postoperative stay, patients’ capability to cough effectively and to perform physiotherapy without stopping due to excessive pain were assessed. Patients were also questioned about their pain using the NRS. In case of NRS >3, inability to perform physiotherapy or effective cough represented the criteria for proposing rescue analgesia with ESPB.
After obtaining informed consent for the procedure, NRS at rest (NRS static) and during movements (NRS dynamic) was recorded; blood gas analysis and spirometry were performed to evaluate PaO2/FiO2 (P/F), forced vital capacity (FVC), and forced expiratory volume in 1 second (FEV1) before ESPB execution.
To perform ESPB, the patient was placed in side position. For ultrasonographic guidance, a high-frequency HFL-50 15–6 MHz linear transducer was used (Sonosite M-Turbo, Bothell, WA) and the block was performed with out-of-plane approach using a 21G, 50-mm needle (B-Braun Sonoplex, Melsungen, Germany) at T3 and T6 administering 10 mL of ropivacaine 0.5% for each level. ESPB was considered successful when a linear spread of fluid between the erector spine muscles and transverse process upon injection was shown. The ESPB was performed in a strictly sterile manner.
After performing the ESPB, NRS static and dynamic, P/F, and FVC and FEV1 were recorded at 40 minutes and 80 minutes. To compare the data acquired, a Student t test was used, using Social Science Statistics software (https://www.socscistatistics.com/tests/). Due to the small number of cases analyzed, a Shapiro-Wilk test was performed before Student t test in order to ensure normal distribution of the sample.
Results
During the study, 84 patients underwent thoracic surgery, and 7 of them needed ESPB as rescue analgesia. Patient characteristics and surgical approach are reported in Table 1. Among the patients treated with ESPB, there were 4 patients with mild chronic obstructive pulmonary disease (COPD) and 3 with moderate COPD. The average time from surgery end to rescue ESPB was 22 hours; in 3 cases, patients needed antalgic rescue before 12 hours from surgery: these cases were considered as TPVB failure.
Patient characteristics and surgical approach.
BMI: body mass index; ESPB: erector spine plane block; RATS: robotic-assisted thoracic surgery; VATS: video-assisted thoracic surgery.
NRS had a significantly greater improvement (p < 0.05) in rest than in dynamic assessment. No further improvement was reported after the first 40 minutes (Table 2).
Static and dynamic numeric rating scale (NRS) score before and 40 and 80 minutes after erector spine plane block.
P/F did not show significant improvement; spirometric parameters improved. FVC had significant improvement after 80 minutes; FEV1 was increased after 40 minutes (Table 3). No opioids were needed to manage postoperative pain in these patients.
PaO2/FiO2 (P/F), forced vital capacity (FVC), and forced expiratory volume in 1 second (FEV1) before and 40 and 80 minutes after erector spine plane block.
No intraoperative or postoperative complications occurred during the hospital stay.
Discussion
Despite established standards, effective treatments, and evidence-based guidelines, postoperative pain control in Italy remains suboptimal. 13 The major obstacles to optimal postoperative pain management are inadequate training of caregivers, lack of time and organization, and lack of equipment.
There is a greater need for analgesia in the first 24 hours after surgery due to the postoperative pain peak that occurs during this time 6 in case of no continuous local anesthetic administration, like in continuous TEA or TPVB.
ESPB has been used not only for thoracic surgery but also for breast surgery, orthopedic surgery, spine surgery, and kidney surgery, but never as a rescue technique, without catheter placement, for postoperative pain control.
According to our experience, the insertion of a catheter below the erector muscle of the spine does not offer significant advantages, and there is the risk of displacement due to reduced ability to spread the local anesthetic when administered through a catheter.
The use of ESPB as postoperative rescue analgesia could represent an incentive for the use of locoregional analgesia techniques due to the reduced side effects compared to TEA and TPVB and to greater safety, making it easy to perform in the thoracic surgical ward or even in an outpatient clinic setting. 12
The ESPB, due to the lack of direct effects on the neuraxial structures, is less likely to produce a hematoma along the spinal cord, allowing patients at high risk for this complication to benefit from its analgesia.9,10
Moreover, ESPB as rescue therapy has been useful to reduce opioid requirements during the perioperative period, according to the current goals of enhanced recovery programs. Local anesthetics can be used alone in patients with intolerable opioids-related side effects, such as prolonged postoperative ileus or severe nausea and vomiting, while effective analgesia is provided. 14
Our sample is small and should be considered as an indicative sample. In consideration of the low number of patients treated, any statistical significance cannot go beyond the limits of this study, therefore our results should be viewed as an improvement trend rather than a strong indication. ESPB has given relevant results especially in terms of improving the NRS (p < 0.05) at rest and in dynamic assessment in the first 40 minutes after ESPB execution, even if no further improvement has been reported after the first 40 minutes. This improvement of pain symptomatology is important in order to allow patients to be able to perform physiokinesitherapy after the execution of the ESPB.
The P/F did not show any improvement, probably related to the presence of pathology of the lung parenchyma, such as COPD, which is often found in patients undergoing thoracic surgery and is not modified by the application of analgesic techniques.
According to current knowledge,15,16 poor postoperative FEV1 correlates with an increase in postoperative complications, so our finding of increased FEV1 after 40 minutes could be considered as a promising index of improvement in the patient’s outcome.
FVC had a relevant improvement only after 80 minutes. This finding could be due to the longer time and the specific diaphragmatic exercise necessary to obtain a valid improvement of FVC.17,18 No differences according to surgical procedures or surgical access were reported. Furthermore, we underline that this technique, performed at the bedside both in the intensive care unit setting and in the ward, has not failed or been associated with complications.
Given the small sample of our study, it is not possible to draw conclusions concerning the outcome of the patients. The concept of statistical significance is not adequate in relation to the low number of cases present in this sample and is likely to be too striking in the context of such a small number of patients, but our work is a demonstration of the feasibility of ESPB as an analgesic rescue therapy in patients undergoing thoracic surgery. This leads to 2 further considerations: ESPB can be included among the locoregional analgesia techniques practicable by the acute pain service for postoperative pain management and should be considered as a tool for postoperative pain therapy especially in thoracic surgery where there is a lack of use of locoregional analgesia techniques for treatment and postoperative pain control.
Footnotes
Declaration of conflicting interests
The authors declare no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding
The authors received no financial support for the research, authorship, and/or publication of this article.
