BJA -- E-letters for Ng and Swanevelder, 98 (2) 159-162

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Electronic Letters to:

Editorials:
A. Ng and J. Swanevelder
Pain relief after thoracotomy: is epidural analgesia the optimal technique?
Br. J. Anaesth. 2007; 98: 159-162 [Full text] [PDF]

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Electronic letters published:

Posoperative shoulder pain after thoracotomy: Juarez Mundim, Roberto Castro, Vera Coelho and Bráulio Mesquita (25 June 2007)

Pain relief after thoracotomy: Hanna Misiolek, Aleksandara Kwosek and Piotr Knapik (10 June 2007)

Pain relief after thoracotomy: Alexander Ng, J Swanevelder (13 March 2007)

Pain relief after thoracotomy: Ian McGovern, Christopher Walker, and Felicia Cox (16 February 2007)

Posoperative shoulder pain after thoracotomy 25 June 2007

Juarez Mundim ,
Roberto Castro, Vera Coelho and Bráulio Mesquita
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Re: Posoperative shoulder pain after thoracotomy

We paid attention to the editorial about alternatives to pain's relief after thoracotomy. Here at our hospital, continuous thoracic paravertebral blockade is frequently used after this kind of surgery.
We would like to remember the strong pain in the shoulder that can occur after thoracic surgery cited by the author, even with effective thoracic epidural analgesia (1). As described in the text, despite of being related only to thoracic epidural technique, it's not a surprise if we have it with the thoracic pravertebral blockade too.
We mention a case report by which a female patient, 67 years-old, was submmited to a thoracotomy for metastasis ressection. Postoperative analgesia was made with continuous paravertebral blockade (ropivacaine 0,2% - 10ml/h). In the posoperative period, patient complained about a strong pain in the right shoulder was relieved with endovenous morphine.
We don't have studies showing the incidence of this kind of pain with the thoracic paravertebral blockade, but we share the idea it can occur.
References: - British Journal of Anaesthesia 98 (2) 159-62 (2007)
Conflict of Interest:
None declared

Pain relief after thoracotomy 10 June 2007

Hanna Misiolek
Medical University of Silesia, Department od Anaesthesia and Intensive Care, Zabrze Poland,
Aleksandara Kwosek and Piotr Knapik
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Re: Pain relief after thoracotomy

We have read the article “Pain relief after thoracotomy: is epidural analgesia the optimal technique?” by A. Ng and J. Swanevelder (Br J Anaest, 2007,98:159-62) with great interest. The authors analyzed the literature concerning various methods of post-thoracotomy pain relief. Much work has already been done in a search for the optimal method of pain control after major thoracic procedures. Maximal efficacy and minimal potential for side effects or complications are the most important issues.[1]
The choice of regional analgesia may include such techniques as epidural analgesia (EA), paravertebral blockade (PVB) or intrathecal analgesia (ITA), however all of them are associated with the occurrence of side-effects. [2,3] Properly organized acute pain service (APS) may be therefore as important as a choice of the anaesthetic technique.[4,5]
In our department we first introduced acute pain service for patients after thoracic procedures and it then spread into all postoperative patients. We apply most of available techniques of regional anaesthesia, i.e. epidural analgesia (standard or patient-controlled) and paravertebral blockade.
Material and method: Since March 2000 till the end a year 2006 our acute pain service cared for 1043 patients following major thoracic procedures with the use of thoracic epidural technique. After Ethical Committee approval, we started to analyze prospectively a quality of postoperative pain relief in these patients.
Epidural catheter was not inserted in patients with abnormal clotting results (PT>20 sec., APTT>50 sec., platelet count <150 G/l). Patients were also excluded if they did not give their consent to the placement of the epidural catheter and to participate in the study. In addition, epidural anaesthesia was not considered in patients scheduled for minor thoracic procedures with the low predicted intensity of pain (less than 4 points according to Visual Analogue Scale) and with a short predicted period of postoperative pain (less than 3 postoperative days).
Epidural catheter was inserted before the operation at a level anywhere between T4 and T8. Mixture of 0.0625% bupivacaine and 6 µg mL-1 fentanyl was administered to the epidural space after operation. In case of unsatisfactory analgesia, the first step was to increase the rate of epidural infusion, and the second – replacement of the mixture to/for 0.125% bupivacaine and 6 µg mL-1 fentanyl. When arterial blood pressure had reduced below 30% of pre-operative/initial pressure, the mixture was changed to10 µg mL-1 fentanyl alone.
Constant monitoring of basic haemodynamic and respiratory parameters was started in a postoperative period and registered approximately 3 times a day during regular rounds of an APS team. Apart from vital signs, standard assessment also included monitoring of pain intensity according to Prince Henry Hospital Pain Score (PHHPS) the extent of sedation (Ramsay Score - RS), and the incidence of complications. Brief neurological examination was performed during each visit to investigate the early symptoms of haematoma and spinal compression (the presence of paraesthesiae, motor blockade or/and the absence of touch sensation in lower extremities). All data were written in a special protocol and were incorporated into the database.
Results: Mean age of studied patients was 54.8 ± 12.3 years. 750 patients (72%) were male. Mean treatment time was 3.7 ± 1.6 days. Nurses conducted 84% of all visits of the APS team – the remaining visits were performed by the anaesthetists. Epidural continuous infusion of 0.0625% bupivacaine and fentanyl 6 µg mL-1 was administered to 77% of patients for the whole treatment time. The change to solution of 0.125% bupivacaine with 6 μg mL-1 fentanyl was needed in 21% of all patients. Solution of 10 μg mL-1 fentanyl alone was applied to 2% of patients.
In total, 10571 measurements in 962 patients were performed (about 11 measurements per patient). Satisfactory analgesia (PHHPS≤1) was found in 9985 measurements (95%). Mean amplitude of systolic and diastolic blood pressure was 40 ± 18 mmHg and 23 ± 10 mmHg, respectively. Optimal level of sedation (grade 2 according to Ramsay Score) was registered in 10189 measurements (97%). Easily curable side effects or complications leading to premature termination of epidural analgesia were noted overall in 275 (25.4%) patients. No major complications occurred.
Side effects and complications of epidural analgesia coordinated by APS:
1. Easily curable side effects - (193) 18.5%;
- Hypotension (ABP reduction > 30% of initial ) - (78) 7.5%;
- Paresthesia - (72) 6.9%;
- Pruritus - (31) 3.0%;
- Nausea - (12) 1.1%;
2. Complications causing premature finish of EA - (72) 6.9%;
- Accidental removal of epidural catheter - (43) 4.1%;
- Inflammation of skin around the catheter - (19) 1.8%;
- Occlusion - (10) 1.0%;
Due to constant monitoring, all side-effects and complications that may always occur during epidural analgesia were immediately noticed and treated. Discussion: Paravertebral technique is used in our centre mainly for minor surgical procedures (i.e. Video Assisted Thoracoscopy- VATS) and in patients with coagulopathy. In some selected cases, we administered ropivacaine instead of bupivacaine, because it has been previously confirmed, that there is less decrease of blood pressure when this agent is used for intraoperative epidural analgesia. We therefore administered ropivacaine when maximal concentration of a local anaesthetic was necessary .[1] All things considered, we think that although there are many techniques of pain relief after thoracotomy, thoracic epidural analgesia should be still regarded a gold standard because it is highly effective and safe. Moreover thoracic epidural techniques with local anaesthetics may benefit patients undergoing and after major thoracic surgery by effectively blocking cardiac sympathetic nerve activity and improving the myocardial oxygen supply-demand balance. [6] Conclusion: Professionally organized system of patient’s care as well as a control of the efficacy of analgesia with the use of acute pain service is at least as important as a choice of the anaesthetic technique.
1. Niemi G, Breivik H. Epinephrine markedly improves thoracic epidural analgesia produced by a small-dose infusion of ropivacaine, fentanyl and epinephrine after major thoracic or abdominal surgery: a randomized, double-blinded crossover study with and without epinephrine. Anesth Analg 2002;94:1598–605.
2. Davies RG, Myles PS, Graham JM. A comparison of the analgesic efficacy and side effects of paravertebral vs epidural block after thoracotomy – a systematic review and meta-analysis of randomized trials. Br J Anaesth 2006;96:418–26.
3. Perttunen K, Nilsson E, Heinonen J, Kirvisalo EL, Salo JA, Kalso E. Extradural, paravertebral and intercostals blocks for post-thoracotomy pain. Br J Anaesth 1995;75:541–7.
4. Cook TM, Riley RH. Analgesia following thoracotomy: a survey of Australian practice. Anaesth Intensive Care 1997;25:520-4.
5. Rawal N. Organization, function, and implementation of acute pain service. Anesthesiol Clin North America 2005;23:211-25.
6. Chaney MA. Intrathecal and epidural anesthesia and analgesia for cardiac surgery. Anesth Analg 2006;102:45-64
Conflict of Interest:
None declared

Pain relief after thoracotomy 13 March 2007

Alexander Ng,
Consultant Anaesthetist ,
J Swanevelder
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Re: Pain relief after thoracotomy

AUTHOR'S REPLY TO E-LETTER
Dear Editor
Thank you very much for the opportunity to respond to the letter from McGovern (and colleagues).1 We appreciate his comments as acute and chronic pain after thoracotomy is a problem and thus requires healthy debate.3-5
The first point to which McGovern refers is the postoperative administration of intravenous (i.v.) morphine by Patient Controlled Analgesia (PCA).1 We would like to stress that morphine by PCA was neither mentioned nor implied in our Editorial.2 We suggested that a bimodal technique comprising low-dose intrathecal morphine and a paravertebral infusion of local anaesthetic would be effective for analgesia after thoracotomy. In this situation, morphine by PCA would not be required.
In his second point, McGovern describes his study in which intrathecal morphine 0.25 to 0.50 mg and i.v. morphine by PCA were administered to patients who had thoracoscopic talc pleurodesis.6 Although we were unable to obtain further details of the study from the reference supplied, naloxone appeared to be necessary in 10% of patients. This problem is a possibility after administration of opioids and we would like to assert that epidural opioids are also associated with concentration-dependent respiratory depression.7
In addition, we find it surprising that intrathecal morphine was used for management of pain after talc pleurodesis. We suggest that intrathecal morphine should be reserved for video assisted thoracoscopic procedures that are associated with more anticipated tissue damage and nociception eg decortication and lobectomy. In these circumstances, we have found that naloxone is not necessary and that postoperative i.v. morphine by PCA is seldom required. Patients are often taking oral analgesics which seem to be sufficient to bridge the “analgesic gap” when the effects of intrathecal morphine have dissipated.8
In his third point, McGovern admits that epidural analgesia is associated with hypotension which may be managed adequately by fluid administration. He purports that vasoconstrictors are not required normally.1 Whilst this hypothesis may be conceivable for patients who have had general surgery, it may be less credible for patients who are at risk of lung injury, after thoracotomy.9 Indeed, patients with limited lung function, particularly those who have had a pneumonectomy, should be given fluids sparingly and thus we suggest that paravertebral blockade may allow more judicious administration of fluids than epidural analgesia.
The fourth point is concerned with publication bias and intervention studies on pain relief after thoracotomy.1 From a recent meta-analysis of randomised controlled clinical trials comparing epidural analgesia with paravertebral block, there seems to be reasonable statistical evidence that paravertebral analgesia alone is more optimal for analgesia than a thoracic epidural.10 This inference has arisen, not because paravertebral block is better for pain relief than epidural analgesia, but because it is associated with a significantly lower occurrence of several adverse outcomes eg hypotension, urinary retention, block failure and nausea. Such limiting effects may impede recovery and rehabilitation in the postoperative period.11 To provide analgesia prior to insertion of a paravertebral catheter at the end of surgery, we suggested that low-dose intrathecal morphine would be useful as part of a bimodal analgesic plan.
In conclusion, thoracic epidurals are effective for analgesia after thoracotomy and will be the preferred choice of many anaesthetists. However, we have presented evidence to show that this method may not be the most optimal. We hope that we have rekindled the search for the Holy Grail of pain relief after thoracotomy.
References 1 McGovern I, Walker C, Cox F. Pain relief after thoracotomy. Br J Anaesth 2007.
2 Ng A, Swanevelder J. Pain relief after thoracotomy; is epidural analgesia the optimal technique. Br J Anaesth 2007;98:159-162.
3 Ochroch EA, Gottschalk A, Augostides J, Carson KA, Kent L, Malayaman N, Kaiser LR, Aukburg SJ. Long-term pain and activity during recovery from major thoracotomy using thoracic epidural analgesia. Anesthesiology 2002;97:1234-44.
4 Perkins FM, Kehlet K. Chronic pain as an outcome of surgery: a review of predictive factors. Anesthesiology 2000;93:1123-33.
5 Senturk M, Ozcan PE, Talu GK, Kiyan E, Camci E, Ozyalcin S, Dilege S, Pembeci K. The effects of three different analgesia techniques on long term postthoracotomy pain. Anesth Analg 2002;94:11-5.
6 Walker CPR. Intrathecal morphine (IT) as an adjunct to intravenous (IV) patient-controlled analgesia (PCA) in thoracoscopic talc pleurodesis. In 13th World Congress of Anaesthesiologists. 2004. Paris. France.
7 Tan CNH, Guha A, Scawn NDA, Pennefather SH, Russell GN. Optimal concentration of epidural fentanyl in bupivacaine 0.1% after thoracotomy. Br J Anaesth 2004;92:670-4.
8 Ng A, Hall F, Atkinson A, Kong KL, Hahn A. Bridging the Analgesic Gap Acute Pain 2000;3:172-80.
9 Baudouin SV. Lung injury after thoracotomy. Br J Anaesth 2003;91:132-42.
10 Davies RG, Myles PS, Graham. A comparison of the analgesic efficacy and side effects of paravertebral vs epidural blockade after thoracotomy – a systematic review and meta-analysis of randomized trials. Br J Anaesth 2006;96:418-26.
11 Bonnet F, Marret E. Influence of anaesthetic and analgesic techniques on outcome after surgery. Br J Anaesth 2005;95:52-8.
Conflict of Interest:
None declared

Pain relief after thoracotomy 16 February 2007

Ian McGovern,
Consultant
Royal Brompton and Harefield NHS Trust,
Christopher Walker, and Felicia Cox
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Re: Pain relief after thoracotomy

We read with interest your editorial regarding alternatives to epidural analgesia after thoracotomy[1] and congratulate the authors on their account of the pathophysiology of pain following thoracotomy. However we are concerned that their advocacy of intrathecal morphine as an adjunct to paravertebral analgesia in place of thoracic epidural analgesia may be over- enthusiastic.
It is widely believed that intrathecal morphine will provide analgesia for up to 24 hours before additional administration of opioid is required.[2] Following a single intrathecal dose of opioid, the subsequent means of delivering opioid would be via an intravenous patient-controlled analgesia system. Even when combined with a paravertebral infusion of local anaesthetic solution, supplementary systemic opioids will be required after 24 hours. There is potential for significant respiratory depression during the overlapping of the residual intrathecal opioid and the subsequent intravenous opioid. On a more practical note, the presence of a concurrent paravertebral local anaesthetic infusion necessitates the use of a second infusion device with all the cost and risk management implications that that entails. An epidural catheter with a single infusion of a combination of local anaesthetic and opiate can safely be left in situ for up to 72 hours and avoids the need for a second infusion device.
We recognise that in a large case series of patients undergoing mainly non- thoracic surgical interventions, the serious adverse effects of intrathecal opioid administration, with a dose range of 0.2-0.8mg, are relatively low (3%) [3]. Our experience would suggest that in the rather elderly and often respiratory-impaired thoracic surgical patient population the incidence is somewhat greater. In our randomised controlled study looking at the role of intrathecal morphine as an adjunct to intravenous patient-controlled analgesia following thoracoscopic talc pleurodesis surgery we found a single lumber intrathecal injection of preservative-free morphine (5?g kg-1, range 0.25-0.5mg) resulted in an incidence of respiratory depression requiring treatment with naloxone of 10%.[4] As a result we have become more wary of this technique.
In discussing the side effects of thoracic epidural analgesia when compared to paravertebral administration of local anaesthesia we would suggest that the hypotension often associated with thoracic epidural analgesia and, to perhaps a lesser extent, paravertebral blockade[5] is largely due to an unmasking of underlying hypovolaemia and can usually be alleviated with appropriate and judicious fluid replacement. We note that the studies that demonstrated a greater hypotensive effect with epidural block used a bupivicaine 0.25% infusion regime. Our practise is to combine levo- bupivicaine 0.125% with fentanyl 4?g ml-1 in our thoracic epidural infusions. Hypotension requiring vasoconstrictor therapy is rarely a problem.
We have been unable to find a randomised controlled trial comparing thoracic epidural analgesia with the combination of intrathecal opioids and paravertebral analgesia in thoracotomy patients. Davies et al’s review concedes that “negative studies are less likely to be submitted or accepted for publication and considerable variation can exist between studies in terms of different interventions and different clinical circumstances.”[5] This potential for publication bias should not be ignored when authors commend a potenti ally useful but untested alternative analgesic technique without the support of randomised controlled trials.
We applaud the debate Drs Ng and Swanevelder will not doubt stimulate, but feel that any technique for providing pain relief after thoracotomy will have to be compared to the gold-standard of a thoracic epidural infusion delivering a combination of local anaesthetic solution and opioid, and must be effective for at least 24 hours postoperatively.
References
1. Ng, A. and J. Swanevelder, Pain relief after thoracotomy: is epidural analgesia the optimal technique? Br J Anaesth, 2007. 98(2): p. 159-62.
2. Neustein, S.M. and E. Cohen, Intrathecal morphine during thoracotomy, Part II: Effect on postoperative meperidine requirements and pulmonary function tests. J Cardiothorac Vasc Anesth, 1993. 7(2): p. 157-9.
3. Gwirtz, K.H., et al., The safety and efficacy of intrathecal opioid analgesia for acute postoperative pain: seven years' experience with 5969 surgical patients at Indiana University Hospital. Anesth Analg, 1999. 88(3): p. 599-604.
4. Walker, C.P.R., et al. Intrathecal (IT) morphine as an adjunct to intravenous (IV) patient-controlled analgesia (PCA) in thoracoscopic talc pleurodesis surgery. in 13th World Congress of Anaesthesiologists. 2004. Paris, France.
5. Davies, R.G., P.S. Myles, and J.M. Graham, A comparison of the analgesic efficacy and side-effects of paravertebral vs epidural blockade for thoracotomy--a systematic review and meta-analysis of randomized trials. Br J Anaesth, 2006. 96(4): p. 418-26.
Conflict of Interest:
None declared