A prospective, randomized, blinded comparison between continuous thoracic paravertebral and epidural infusion of 0.2% ropivacaine after lung resection surgery

Analgesia in post-thoracotomy patients: Comparison between thoracic epidural and thoracic paravertebral blocks

BACKGROUND

Acute postoperative pain can cause detrimental effects on multiple organ systems, leading to chronic pain syndromes.

OBJECTIVE

To compare thoracic epidural block (TEB) and paravertebral block (PVB) for relief of postoperative pain in adult patients undergoing thoracotomy.

MATERIALS AND METHODS

In this randomized, single-blinded, prospective study, 60 adult patients of both sexes, belonging to ASA physical status I and II, were scheduled for elective thoracotomy under general anesthesia. They were randomly divided into two groups, A and B of 30 each, who were comparable in terms of demographic parameters and body weight. Group A received TEB and Group B received PVB. All the patients underwent thoracotomy under general anesthesia using a uniform standard anesthetic technique. Thirty minutes before the anticipated end of skin suture, blocks were activated in both the groups with 7.5 ml for TEB and 15 ml for thoracic PVB of 0.25% bupivacaine, along with 1 ml of fentanyl for postoperative analgesia.

RESULTS

Patients receiving PVB for postoperative analgesia experienced better analgesia than those receiving TEB from the immediate postoperative period that lasted longer. Intragroup comparison showed that in the cases receiving TEB, there was a significant statistical difference in preoperative and postoperative values with regard to the mean systolic blood pressure (SBP), mean arterial pressure and mean pulse rate. However, in patients receiving PVB, significant difference in preoperative and postoperative values was seen in mean SBP only.

CONCLUSIONS

We observed longer duration of analgesia with PVB compared to TEB.

A systematic review of comparative studies indicates that paravertebral block is neither superior nor safer than epidural analgesia for pain after thoracotomy

Background

The “gold standard” for pain relief after thoracotomy has been thoracic epidural analgesia (TEA). The studies comparing TEA with paravertebral block (PVB) and recent reviews recommend PVB as a novel, safer method than TEA.

Methods

A systematic search of the Cochrane and PubMed databases for prospective, randomized trials (RCTs) comparing TEA and PVB for post-thoracotomy analgesia was done. We assessed how TEA and PVB were performed, methods of randomization, assessment of pain relief, and complications. Abstracts only were excluded.

Results

Ten studies were included, comprising 224 patients randomized to TEA, 243 to PVB. The studies were heterogeneous. Therefore, a systematic narrative review with our evaluations is presented.

Only 3/10 trials reported the method of randomization. Pain during coughing was reported in only 5/10, pain assessment not specified in 5/10. Only 1/10 trials found PVB superior to TEA, but placed TEA catheters too low (<T7). TEA was superior to PVB in 1/10, during first 1.5 days. PVB and TEA were equally effective in 8/10. 5/10 trials found PVB had less hypotension or urinary retention. None of the studies used appropriate and optimal TEA: TEA was started after end of surgery in half, catheters placed too low (2/10), too high (1/10), not reported in (1/10). 7/10 infused local anaesthetic only, 2/10 added fentanyl, 1/10 added morphine, and none added adrenaline. PVB infusions had higher concentration of bupivacaine (5 mg/ml) in 2/10, 1/10 added fentanyl, 1/10 added ornipressin. Loading doses were higher in 5/10, and with more concentrated solutions in 5/10 of PVB than in the TEA group.

Conclusions

10 heterogeneous, mostly small, studies comparing TEA and PVB for post-thoracotomy analgesia do not allow conclusions on which method has superior analgesic efficacy and safety. The main methodological problem was that none of the studies use optimal thoracic epidural analgesia, with siting of catheters inappropriate in some and the epidural infusion containing too concentrated local anaesthetic because opioid and adrenaline were not added. Anatomical considerations (the paravertebral space comprises parts of the epidural space and contains spinal cord arteries) and personally experienced complications with PVB (paraplegia) convince us that PVB must have higher risk of, infrequent but serious, spinal cord complications than TEA. Percutaneous PVB may puncture pleura and lung.

Some surgeons expressed satisfaction with PVB because the method omits costly acute pain services for monitoring on surgical wards and saves time in the operating room. They are, however, bound to experience serious complications from PVB, sooner or later.

To our knowledge, optimally conducted epidural analgesia has not been compared with PVB. Current literature and our experience with both techniques for up to four decades, indicate that PVB may be an alternative for post-thoracotomy pain when TEA is infeasible for various patient-related reasons (Breivik et al., 2009). Severely disturbed haemostasis is a contraindication for PVB and TEA. Higher concentrations of local anaesthetics are needed to obtain intercostal nerve blocks and epidural analgesia with PVB, risking local anaesthetic intoxication. Robust monitoring regimen for effects and adverse effects is as important for PVB as for TEA.

Update on the role of paravertebral blocks for thoracic surgery: are they worth it?

PURPOSE OF REVIEW

To consider optimal analgesic strategies for thoracic surgical patients.

RECENT FINDINGS

Recent studies have consistently suggested analgesic equivalence between paravertebral and thoracic epidural analgesia. Complications appear to be significantly less common with paravertebral analgesia.

SUMMARY

There is good evidence that paravertebral block can provide acceptable pain relief compared with thoracic epidural analgesia for thoracotomy. Important side-effects such as hypotension, urinary retention, nausea, and vomiting appear to be less frequent with paravertebral block than with thoracic epidural analgesia. Paravertebral block is associated with better pulmonary function and fewer pulmonary complications than thoracic epidural analgesia. Importantly, contraindications to thoracic epidural analgesia do not preclude paravertebral block, which can also be safely performed in anesthetized patients without an apparent increased risk of neurological injury. The place of paravertebral block in video-assisted thoracoscopic surgery is less clear.

Thoracic paravertebral block (PVB) analgesia

Paravertebral blockade is a safe and effective technique for intraoperative and postoperative management of acute surgical pain. The block may be performed as a single injection or a catheter may be inserted to allow for the continuous or bolus administration of a long acting local anaesthetic. This mode of analgesia is not considered to be a stand alone technique (in contrast to epidural analgesia) and most patients will require additional analgesia (usually parenteral patient controlled analgesia). Compared to epidural analgesia, the paravertebral administration of analgesia is considered to be safer in anti-coagulated patients, but the risk of local anaesthetic toxicity remains. There is little published about the care of patients receiving this form of analgesia. This article provides an overview of the technique of thoracic paravertebral analgesia, the choice of analgesics and side effects together with recommendations for patient care.

Postthoracotomy pain management problems

Pain after thoracotomy is very severe, probably the most severe pain experienced after surgery. Thoracic epidural analgesia has greatly improved the pain experience and its consequences and has been considered the standard for pain management after thoracotomy. This view has been challenged recently by the use of paravertebral nerve blocks. Nevertheless, severe ipsilateral shoulder pain and the prevention of the postthoracotomy pain syndrome remain the most important challenges for management of postthoracotomy pain.