- Email: [email protected]
Analgesia for thoracotomy
THORACIC ANAESTHESIA
Analgesia for thoracotomy
Learning objectives
Lee Feddy After reading this article you should be able to: C describe the mechanisms of pain associated with thoracotomy C discuss the analgesic options for thoracotomy C appreciate post-thoracotomy pain syndrome
Christopher Rozario
Abstract Thoracotomy pain, if untreated, is excruciating and risks acute and chronic complications. Muscle dissection, rib retraction and intercostal nerve damage activate nociceptors. Management is challenging particularly with pre-existing respiratory and co-morbid disease. The gold standard of thoracic epidural analgesia is potentially eclipsed by paravertebral blockade. Post-thoracotomy pain syndrome, previously understated, is a significant problem.
be delivered via continuous infusions or patient-controlled devices. TEA reduces sympathetic discharge, right heart strain, dysrhythmias and ischaemia. Epidural analgesia is more efficacious than intravenous opiates in patients undergoing major thoraco-abdominal surgery.1 Paravertebral blocks (PVB): the thoracic paravertebral space is wedge shaped, lies lateral to the vertebral column and communicates between adjacent levels. It contains spinal nerves, white and grey rami communicantes, the sympathetic chain, intercostal vessels and fat (Table 1). Systematic reviews demonstrate equivalent analgesia compared to TEA, but with fewer complications.2 For spread greater than four dermatomes multiple level injections of 3e5 ml are required. Ultrasound guidance (Figure 1) and catheter insertion by surgeons under direct vision is increasingly popular. The UK Pneumonectomy Outcome Study indicated clinician preference for TEA over PVB. Nevertheless TEA was associated with poorer outcome. PVB may be preferable in patients taking anti-platelet therapy.3
Keywords Epidural analgesia; paravertebral blockade; post-thoracotomy pain syndrome (PTPS)
Mechanisms of pain Ad and C fibres transmit noxious stimuli via intercostal nerves (skin and muscle), the vagus nerve (lung and mediastinum) and the phrenic nerve (mediastinum, pericardium and diaphragm). Parietal pleural innervation is extensive whereas visceral response is mainly to stretch. Cervical root and brachial plexus transmission is via the thoracodorsal and long thoracic nerves. Rib retraction or fracture with costochondral and costovertebral joint disruption damages nerves. Nociceptor and central neuronal sensitization can cause allodynia and hyperalgesia.
Intercostal nerve blocks: the neurovascular bundle lies on the inferior border of each rib but anatomical variation exists. Access is achieved percutaneously or at surgery. This block is inadequate alone, but may supplement insufficient TEA or PVB. Blockade is achieved anywhere proximal to the mid-axillary line; where the lateral cutaneous branch originates. Spread occurs distally and proximally along the subcostal groove.
Surgery Access is via a posterolateral incision in a mid-thoracic intercostal space. To prevent latissimus dorsi division anterolateral and axillary incisions are commonly used. Clamshell thoracotomies involve bilateral anterolateral incisions and a sternotomy. These facilitate invasive resuscitation and, as required, double lung transplantation. Muscle sparing and minimally invasive video-assisted thoracoscopy (VAT) procedures minimize intercostal nerve damage. However prolonged multi-trocar pressure can be counterproductive.
Paravertebral block (PVB)
Surgery is unilateral Uniquely painful
PVB is unilateral Big doses of local anaesthetic are safe Ameliorated
Severe neuroendocrine stress response Endobronchial intubation and chest drain ‘Dynamic’ pain relief required (to clear chest secretions) Rapid mobilization necessary to aid recovery and prevent complications No additional monitoring High incidence of chronic pain
Analgesic techniques Thoracic epidural analgesia (TEA) is best achieved with catheter placement corresponding to the dermatomal level incised. Synergistic combinations of local anaesthetics and opioids reduce hypotension from bilateral sympathetic blockade. Mixtures can
Lee Feddy FRCA is a Trainee in Anaesthesia in Manchester, UK. Conflicts of interest: none declared. Christopher Rozario FFARCSI is a Consultant Anaesthetist at the Lancashire Cardiac Centre, Blackpool, UK. Conflicts of interest: none declared.
ANAESTHESIA AND INTENSIVE CARE MEDICINE 12:12
Thoracic surgery
No risk from needle damage to pleura Excellent pain relief on movement Facilitated through lack of hypotension Critical can be avoided Ameliorated
With kind permission of Professor XX Richardson.
Table 1
563
Ó 2011 Published by Elsevier Ltd.
THORACIC ANAESTHESIA
transmission of diaphragmatic, pleural or pericardial irritation is the most probable explanation and intraoperative infiltration with lignocaine can be effective. Paracetamol and NSAIDs give some relief and although and although interscalene block has been used it risks diaphragmatic dysfunction. Glenohumeral strain during lateral decubitus positioning may be causative. However supraclavicular nerve blocks show no real benefit. Preemptive gabapentin does not reduce its incidence or severity. Post-thoracotomy pain syndrome Pain persisting for at least 2 months without recurrent disease is termed chronic and occurs in up to 67% of patients. Predisposing factors include complexity of surgery, preoperative pain, female gender, age under 60 years and intensity and duration of pain post-operatively. Psychosocial factors and genetic variability in dorsal root ganglia neurotransmitter synthesis may play a role. Limited data support initiating pre-incision TEA or PVB and postoperative continuation to reduce chronic pain. Nerve and tissue damage occur but no association exists between intercostal nerve damage, assessed by nerve conduction studies, and development of chronic pain. Intercostal nerve damage caused by rib resection is actually associated with a lower incidence of post-thoracotomy neuralgia. Inflammatory and immune reactions triggered by damaged axons leads to central hyperexcitability and sensitization. There does appear to be less chronic pain in post-transplant patients on immunosuppressive therapy.
Figure 1 Ultrasound scan of the posterior chest wall; showing the transverse process (TP), costotransverse ligament (CTL), paravertebral space (PVS) and pleura.
Intrapleural injection: this may arise inadvertently following paravertebral blockade. When performed intentionally a catheter may be inserted. However analgesia is unreliable as it’s dependent on pleural integrity, posture and local anaesthetic volume.
Conclusion Intrathecal opioids: nociceptive transmission is interrupted when opioids bind to dorsal horn G-protein-linked receptors in laminae I and II. This reduces release of excitatory neurotransmitters; glutamate and substance P. There is also indirect activation of descending brain stem pathways. Preservative-free morphine is more hydrophilic than fentanyl and diamorphine. This leads to sustained high cerebrospinal fluid concentrations. The risk of cephalic spread and delayed respiratory depression necessitate observation in a critical care setting. Analgesia is variable and oral or parenteral opioid supplementation may be necessary.
Proper planning and provision of analgesia for thoracotomy prevents atelectasis, pneumonia, pulmonary embolism and emergency intensive care admission. Likewise preservation of respiratory effort averts hypoxaemia and hypercarbia with attendant ischaemia and arrhythmias. TEA is widely advocated, but ultrasound-guided PVB is increasingly used as a viable alternative. Despite adequate incisional analgesia shoulder tip pain remains problematic and post-thoracotomy pain syndrome warrants greater consideration than previously afforded. A
Multimodal and opioid-sparing analgesia: paracetamol and oral or parenteral opioids are useful supplements. Ketamine infusions 1e3 mg/kg/minute have been shown to reduce acute pain but have little effect on chronic pain. Non-steroidal anti-inflammatory drugs (NSAIDs) can reduce postoperative opioid consumption by 30%. Nevertheless caution is warranted where restricted fluid intake is advocated (e.g. post pneumonectomy). This is particularly so in patients with pre-existing renal dysfunction. Gabapentin 300e600 mg, intravenous clonidine 3 mg/kg and magnesium 2 g are suggested rescue regimes.
REFERENCES 1 Ali M, Winter DC, Hanly AM, et al. Prospective, randomized, controlled trial of thoracic epidural or patient-controlled opiate analgesia on perioperative quality of life. Br J Anaesth 2010; 104: 292e7. 2 Kotze A, Scally A, Howell S. Efficacy and safety of different techniques of paravertebral block for analgesia after thoracotomy: a systematic review and metaregression. Br J Anaesth 2009; 103: 626e36. € nnqvist PA, Naja Z. Bilateral thoracic paravertebral 3 Richardson J, Lo block: potential and practice. Br J Anaesth 2011; 106: 164e71.
Shoulder tip pain Shoulder tip pain is experienced in 31e97% of patients. Higher incidences follow major pulmonary resection. Phrenic nerve
FURTHER READING Continuing Education in Anaesthesia, Critical Care & Pain J 10: Number 5 2010.
ANAESTHESIA AND INTENSIVE CARE MEDICINE 12:12
564
Ó 2011 Published by Elsevier Ltd.
Analgesia for thoracotomy
Learning objectives
Lee Feddy After reading this article you should be able to: C describe the mechanisms of pain associated with thoracotomy C discuss the analgesic options for thoracotomy C appreciate post-thoracotomy pain syndrome
Christopher Rozario
Abstract Thoracotomy pain, if untreated, is excruciating and risks acute and chronic complications. Muscle dissection, rib retraction and intercostal nerve damage activate nociceptors. Management is challenging particularly with pre-existing respiratory and co-morbid disease. The gold standard of thoracic epidural analgesia is potentially eclipsed by paravertebral blockade. Post-thoracotomy pain syndrome, previously understated, is a significant problem.
be delivered via continuous infusions or patient-controlled devices. TEA reduces sympathetic discharge, right heart strain, dysrhythmias and ischaemia. Epidural analgesia is more efficacious than intravenous opiates in patients undergoing major thoraco-abdominal surgery.1 Paravertebral blocks (PVB): the thoracic paravertebral space is wedge shaped, lies lateral to the vertebral column and communicates between adjacent levels. It contains spinal nerves, white and grey rami communicantes, the sympathetic chain, intercostal vessels and fat (Table 1). Systematic reviews demonstrate equivalent analgesia compared to TEA, but with fewer complications.2 For spread greater than four dermatomes multiple level injections of 3e5 ml are required. Ultrasound guidance (Figure 1) and catheter insertion by surgeons under direct vision is increasingly popular. The UK Pneumonectomy Outcome Study indicated clinician preference for TEA over PVB. Nevertheless TEA was associated with poorer outcome. PVB may be preferable in patients taking anti-platelet therapy.3
Keywords Epidural analgesia; paravertebral blockade; post-thoracotomy pain syndrome (PTPS)
Mechanisms of pain Ad and C fibres transmit noxious stimuli via intercostal nerves (skin and muscle), the vagus nerve (lung and mediastinum) and the phrenic nerve (mediastinum, pericardium and diaphragm). Parietal pleural innervation is extensive whereas visceral response is mainly to stretch. Cervical root and brachial plexus transmission is via the thoracodorsal and long thoracic nerves. Rib retraction or fracture with costochondral and costovertebral joint disruption damages nerves. Nociceptor and central neuronal sensitization can cause allodynia and hyperalgesia.
Intercostal nerve blocks: the neurovascular bundle lies on the inferior border of each rib but anatomical variation exists. Access is achieved percutaneously or at surgery. This block is inadequate alone, but may supplement insufficient TEA or PVB. Blockade is achieved anywhere proximal to the mid-axillary line; where the lateral cutaneous branch originates. Spread occurs distally and proximally along the subcostal groove.
Surgery Access is via a posterolateral incision in a mid-thoracic intercostal space. To prevent latissimus dorsi division anterolateral and axillary incisions are commonly used. Clamshell thoracotomies involve bilateral anterolateral incisions and a sternotomy. These facilitate invasive resuscitation and, as required, double lung transplantation. Muscle sparing and minimally invasive video-assisted thoracoscopy (VAT) procedures minimize intercostal nerve damage. However prolonged multi-trocar pressure can be counterproductive.
Paravertebral block (PVB)
Surgery is unilateral Uniquely painful
PVB is unilateral Big doses of local anaesthetic are safe Ameliorated
Severe neuroendocrine stress response Endobronchial intubation and chest drain ‘Dynamic’ pain relief required (to clear chest secretions) Rapid mobilization necessary to aid recovery and prevent complications No additional monitoring High incidence of chronic pain
Analgesic techniques Thoracic epidural analgesia (TEA) is best achieved with catheter placement corresponding to the dermatomal level incised. Synergistic combinations of local anaesthetics and opioids reduce hypotension from bilateral sympathetic blockade. Mixtures can
Lee Feddy FRCA is a Trainee in Anaesthesia in Manchester, UK. Conflicts of interest: none declared. Christopher Rozario FFARCSI is a Consultant Anaesthetist at the Lancashire Cardiac Centre, Blackpool, UK. Conflicts of interest: none declared.
ANAESTHESIA AND INTENSIVE CARE MEDICINE 12:12
Thoracic surgery
No risk from needle damage to pleura Excellent pain relief on movement Facilitated through lack of hypotension Critical can be avoided Ameliorated
With kind permission of Professor XX Richardson.
Table 1
563
Ó 2011 Published by Elsevier Ltd.
THORACIC ANAESTHESIA
transmission of diaphragmatic, pleural or pericardial irritation is the most probable explanation and intraoperative infiltration with lignocaine can be effective. Paracetamol and NSAIDs give some relief and although and although interscalene block has been used it risks diaphragmatic dysfunction. Glenohumeral strain during lateral decubitus positioning may be causative. However supraclavicular nerve blocks show no real benefit. Preemptive gabapentin does not reduce its incidence or severity. Post-thoracotomy pain syndrome Pain persisting for at least 2 months without recurrent disease is termed chronic and occurs in up to 67% of patients. Predisposing factors include complexity of surgery, preoperative pain, female gender, age under 60 years and intensity and duration of pain post-operatively. Psychosocial factors and genetic variability in dorsal root ganglia neurotransmitter synthesis may play a role. Limited data support initiating pre-incision TEA or PVB and postoperative continuation to reduce chronic pain. Nerve and tissue damage occur but no association exists between intercostal nerve damage, assessed by nerve conduction studies, and development of chronic pain. Intercostal nerve damage caused by rib resection is actually associated with a lower incidence of post-thoracotomy neuralgia. Inflammatory and immune reactions triggered by damaged axons leads to central hyperexcitability and sensitization. There does appear to be less chronic pain in post-transplant patients on immunosuppressive therapy.
Figure 1 Ultrasound scan of the posterior chest wall; showing the transverse process (TP), costotransverse ligament (CTL), paravertebral space (PVS) and pleura.
Intrapleural injection: this may arise inadvertently following paravertebral blockade. When performed intentionally a catheter may be inserted. However analgesia is unreliable as it’s dependent on pleural integrity, posture and local anaesthetic volume.
Conclusion Intrathecal opioids: nociceptive transmission is interrupted when opioids bind to dorsal horn G-protein-linked receptors in laminae I and II. This reduces release of excitatory neurotransmitters; glutamate and substance P. There is also indirect activation of descending brain stem pathways. Preservative-free morphine is more hydrophilic than fentanyl and diamorphine. This leads to sustained high cerebrospinal fluid concentrations. The risk of cephalic spread and delayed respiratory depression necessitate observation in a critical care setting. Analgesia is variable and oral or parenteral opioid supplementation may be necessary.
Proper planning and provision of analgesia for thoracotomy prevents atelectasis, pneumonia, pulmonary embolism and emergency intensive care admission. Likewise preservation of respiratory effort averts hypoxaemia and hypercarbia with attendant ischaemia and arrhythmias. TEA is widely advocated, but ultrasound-guided PVB is increasingly used as a viable alternative. Despite adequate incisional analgesia shoulder tip pain remains problematic and post-thoracotomy pain syndrome warrants greater consideration than previously afforded. A
Multimodal and opioid-sparing analgesia: paracetamol and oral or parenteral opioids are useful supplements. Ketamine infusions 1e3 mg/kg/minute have been shown to reduce acute pain but have little effect on chronic pain. Non-steroidal anti-inflammatory drugs (NSAIDs) can reduce postoperative opioid consumption by 30%. Nevertheless caution is warranted where restricted fluid intake is advocated (e.g. post pneumonectomy). This is particularly so in patients with pre-existing renal dysfunction. Gabapentin 300e600 mg, intravenous clonidine 3 mg/kg and magnesium 2 g are suggested rescue regimes.
REFERENCES 1 Ali M, Winter DC, Hanly AM, et al. Prospective, randomized, controlled trial of thoracic epidural or patient-controlled opiate analgesia on perioperative quality of life. Br J Anaesth 2010; 104: 292e7. 2 Kotze A, Scally A, Howell S. Efficacy and safety of different techniques of paravertebral block for analgesia after thoracotomy: a systematic review and metaregression. Br J Anaesth 2009; 103: 626e36. € nnqvist PA, Naja Z. Bilateral thoracic paravertebral 3 Richardson J, Lo block: potential and practice. Br J Anaesth 2011; 106: 164e71.
Shoulder tip pain Shoulder tip pain is experienced in 31e97% of patients. Higher incidences follow major pulmonary resection. Phrenic nerve
FURTHER READING Continuing Education in Anaesthesia, Critical Care & Pain J 10: Number 5 2010.
ANAESTHESIA AND INTENSIVE CARE MEDICINE 12:12
564
Ó 2011 Published by Elsevier Ltd.