Art & science. Rectus sheath catheter infusions for post-operative pain management

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1 Art & science If you would like to contribute to the Art & science section, The synthesis of art and science is lived by the nurse in the nursing act Josephine G Paterson Rectus sheath catheter infusions for post-operative pain management Layzell M (2014) Rectus sheath catheter infusions for post-operative pain management. Nursing Standard. 28, 42, Date of submission: December ; date of acceptance: February Abstract Managing pain following major abdominal surgery remains a challenge. Traditionally, patient-controlled analgesia (PCA) or epidural analgesia have been used, which have improved post-operative pain and the patient experience, but have presented some problems in recovery. PCA can cause adverse effects, including sedation, nausea, vomiting, and prolonged gastric ileus. While epidurals do have some advantages over PCA, there are risks involved related to catheter insertion and adverse effects, such as hypotension and motor blocks which limit mobility. This article examines rectus sheath catheter infusions, a relatively new and alternative technique to epidural analgesia, and presents some early audit data related to pain scores, analgesic use and mobility. Author Mandy Layzell Lead nurse, acute pain service, Royal Bournemouth and Christchurch NHS Foundation Trust, Bournemouth. Correspondence to: mandy.layzell@rbch.nhs.uk Keywords Abdominal pain, abdominal surgery, analgesia, pain and pain management, post-operative pain, rectus sheath catheters Review All articles are subject to external double-blind peer review and checked for plagiarism using automated software. Online Guidelines on writing for publication are available at For related articles visit the archive and search using the keywords above. ABDOMINAL SURGERY IS associated with severe pain in the post-operative period, which can affect patient satisfaction and delay recovery (Tilleul et al 2012). Over the past two decades there have been several innovations in anaesthetic practice, such as patient-controlled analgesia (PCA) and epidural analgesia, which have transformed the way pain following surgery is managed. Acute pain services oversee safe and effective management of the above techniques in most hospitals. There is increasing evidence that effective and safer alternatives are now being used in clinical practice for thoracic and abdominal surgery (Rawal 2012). These include paravertebral block for thoracotomy, wound catheter infusions for a variety of surgical procedures, transversus abdominis plane (TAP) block and rectus sheath catheters for surgery involving the abdominal wall (Rawal 2012). This article discusses the pathophysiology of abdominal wound pain, reviews some of the current techniques being used to manage pain following abdominal surgery and describes how a new pump for rectus sheath catheters was introduced into clinical practice. A brief summary of audit data is included. Pathophysiology of post-operative pain Pain following surgery is common. Results from a national survey in the Netherlands reported that 80% of patients experienced post-operative pain. Of those, 11% experienced severe pain and 24% reported delay in recovery as a result of pain (Apfelbaum et al 2003). Following major surgical procedures patients typically complain of ongoing pain at rest (Lavand homme 2006). Pain is usually moderate and can, to some degree, be controlled with opioids, paracetamol and non-steroidal anti-inflammatory drugs (NSAIDs). However, pain NURSING STANDARD / RCN PUBLISHING june 18 :: vol 28 no 42 ::

2 Art & science pain management on movement, for example, during coughing and mobilisation, is often severe, may last longer and may not be adequately relieved by opioids (Lavand homme 2006). Generally, major abdominal surgery requires a vertical, midline incision to allow access to all quadrants of the abdomen (Figure 1). The incision goes through layers of skin, subcutaneous fat, muscle and the peritoneum, all of which are richly innervated. Tissue damage caused by surgery stimulates a local physiological inflammatory response. Chemicals are released from damaged tissue, mast cells (histamine, leukotrienes), platelets and plasma components (bradykinin), which cause vasodilation and increased vascular permeability. This response leads to the classic inflammatory signs of redness, heat, swelling and pain. The inflammatory response is essential for structural and functional repair of injured tissue (Hollmann and Durieux 2000). Most pain following major abdominal surgery is related to the wound (Lavand homme 2006). However, as more studies emerge on the use of local anaesthetic infusions into the subcutaneous tissues of abdominal incisions, current evidence shows weak or no benefit to post-operative pain (Beaussier et al 2007). Pain arising in deep muscles and the peritoneum, injured by the surgical incision, appears to play a crucial role in the postoperative pain experience (Beaussier et al 2007). Pain may be induced by light touch in the tissues surrounding the wound (primary hyperalgesia) and by mechanical stimuli in areas some distance away from the wound (secondary hyperalgesia). These are classical changes that occur in the nervous system following surgery (Lavand homme FIGURE 1 A vertical incision to the midline of the abdomen SCIENCE PHOTO LIBRARY 2006). The underlying mechanism causing primary hyperalgesia involves sensitisation of A-delta and C-fibre nociceptors and the conversion of mechanically insensitive (silent) A-delta nociceptors to mechanically sensitive fibres after incision (Wu and Raja 2011). Increased lactate concentrations and low ph occur in skin and muscle wounds following incision, which suggests an ischaemic pain mechanism might contribute to incisional pain (Lavand homme 2006, Wu and Raja 2011). Secondary hyperalgesia affects adjacent tissues, which occurs as a result of central sensitisation. This is caused by enhanced response of dorsal horn neurones in the spinal cord to stimulation received from the peripheral nerves, such as touch. The size and extent of tissue injury will determine the magnitude and duration of this effect (Lavand homme 2006). Analgesia Several techniques are available for providing post-operative analgesia following laparotomy. These include PCA, epidural analgesia, continuous wound infusions and local anaesthetic agents via a rectal sheath catheter. Patient-controlled analgesia Following abdominal surgery, PCA is commonly used. The technique allows patients to administer a small dose of intravenous (IV) opioid when they experience pain. Opioids provide pain relief by binding to opioid receptors in the brain, spinal cord, gastrointestinal and urinary tracts, lung and peripheral nerve endings (Macintyre and Schug 2007). However, as well as providing analgesia, opioids may cause side effects following abdominal surgery, which potentially delay recovery, for example nausea and vomiting, prolongation of gastric ileus, sedation and dizziness (Macintyre and Schug 2007). When compared with intramuscular or subcutaneous opioid analgesia, PCA results in a decrease in opioid-related side effects, increased pain relief and increased patient satisfaction (Macintyre and Schug 2007). However, prolonged gastric ileus increases patient morbidity, lengthens inpatient stay, is a major factor contributing to pain and has major cost implications (Parsons et al 2011). Therefore, PCA may not be the best method of post-operative analgesia for abdominal surgery. Epidural analgesia Epidural infusions have been routinely used to manage pain following abdominal surgery for decades. The technique involves insertion of a small catheter into the epidural space and infusion of local anaesthetic and opioids, to provide segmental 38 june 18 :: vol 28 no 42 :: 2014 NURSING STANDARD / RCN PUBLISHING

3 analgesia (in a belt-like distribution of variable width). Local anaesthetic drugs provide pain relief by blocking spinal nerve impulses. Opioids produce analgesia by blocking opioid receptors in the dorsal horn of the spinal cord (Macintyre and Schug 2007). Epidurals are considered to be the gold standard for post-operative pain management (Rawal 2012) and are associated with several benefits. For example, results from a randomised controlled trial by Rodgers et al (2000), identified a 30% reduction in 30-day mortality, a 55% reduction in pulmonary embolism, a 44% decrease in deep vein thrombosis and a 39% decrease in pneumonia. Meta-analyses comparing epidural analgesia with systemic opioids, have failed to show a decrease in mortality (Rawal 2012). In contrast, a study by Saunders et al (2012) examining emergency laparotomy, found the incidence of mortality to be 14.9%, increasing to 24.4% in patients 80 years or over. Compared with PCA, epidurals provide better pain control for mobilisation for the first 48 hours following open bowel procedures (Beaussier et al 2007). However, certain patients are unsuitable for epidural analgesia because of pre-existing medical conditions, for example infection, coagulopathy, haemodynamic instability or compromised immunity, and wards and nursing staff who are not trained in caring for patients with epidural infusions (Faculty of Pain Medicine of the Royal College of Anaesthetists 2010). Furthermore, patients admitted for emergency laparotomy may be clinically unstable, or may require immediate surgery, making the use of epidural analgesia impossible. Epidural analgesia can provide better pain relief than PCA and is generally thought to be a safe procedure. However, certain risks are associated with performing the procedure, such as spinal haematoma and abscess (Faculty of Pain Medicine of the Royal College of Anaesthetists 2010). Adverse effects related to the drugs used to provide pain relief may also occur, including hypotension, motor and sensory block, urinary retention caused by local anaesthetics and sedation, respiratory depression, nausea and itching caused by opioids (Faculty of Pain Medicine of the Royal College of Anaesthetists 2010). Results from a large prospective project looking at serious complications following epidurals, suggest that the incidence of permanent injury is low (Cook et al 2009). Hermanides et al (2012) claimed that up to 30% of epidurals fail in clinical practice, therefore providing poor or inadequate pain relief. Reasons for failure include incorrect placement or migration after placement and suboptimal dosing of local anaesthetic drugs (Hermanides et al 2012). Although regarded as the gold standard this technique is not suitable for all patients because of the risk of serious complications. Other, less risky techniques such as rectus sheath catheters are available (Niraj et al 2014). Local anaesthetic continuous wound infiltration The use of local anaesthetics for post-operative pain management is well documented as effective in a variety of surgical procedures (Thornton and Buggy 2011, Rawal 2012). Local anaesthetics work by blocking sodium channels in nerves, preventing normal transmission along the nerve resulting in a numbing effect and pain relief (Parry 2011). Generally, the types of blocks performed are one-shot blocks or infiltration of local anaesthetic into wounds (Kehlet and Liu 2007). They have limited efficacy due to the duration of action of local anaesthetics (Kehlet and Liu 2007). Over the last ten years, multi-holed catheters and infusion pumps have become more widely available to enable continuous infusions of local anaesthetic directly into the wound. Catheters are placed in the wound by the surgeon as the wound is closed. This technique is thought to reduce pain by directly reducing the nociceptive bombardment of impulses from damaged nerve endings in the surgical incision and attenuation of the local inflammatory response to injury (Thornton and Buggy 2011). Other effects, which may benefit the patient, include the systemic effects of local anaesthetics, which are thought to have anti-inflammatory properties (Hollmann and Durieux 2000) that may also speed up the return of bowel function (Beaussier et al 2007). The inflammatory process compromises contraction of gastrointestinal smooth muscle after surgery. Local anaesthetics reduce the release of inflammatory agents. However, the benefit of this technique after open abdominal surgery remains unclear, with current evidence suggesting weak or no benefit (Beaussier et al 2007). The reason for this is based on the fact that both fascia of the abdominal muscles and peritoneum are injured by the incision and a catheter placed in the subcutaneous tissues is unlikely to provide pain relief to these deeper layers (Beaussier et al 2007). Rectus sheath catheters The rectus sheath block is a regional anaesthetic technique that was first described at the turn of the 20th century (Parsons et al 2011). The technique aims to block the 7th to 12th intercostal nerves that supply the rectus abdominus muscle and overlying skin (Figure 2). Between the rectus muscles and the posterior rectus sheath there is a potential space. With the use of ultrasound it is possible to place two catheters accurately, one either side of the wound, into this space to provide pain relief using local anaesthetic. NURSING STANDARD / RCN PUBLISHING june 18 :: vol 28 no 42 ::

4 Art & science pain management FIGURE 2 The catheters could be placed by the anaesthetist at the beginning or end of surgery using ultrasound, or intraoperatively by the surgeon who can see exactly where the catheter is placed before closing the wound. The main disadvantages of intraoperative placement by the surgeon include potential soiling of the sterile compartment and leaking of anaesthetic agents from the rectus sheath into the abdominal cavity (Webster 2010). The technique is used for surgery with midline abdominal incisions (Figure 1). The block provides dense and predictable analgesia over the middle anterior wall from the xiphoid process to the symphysis pubis. The block will not provide analgesia for the lateral area of the abdomen, but will provide somatic pain relief for abdominal wall structures superficial to the peritoneum. In abdominal procedures where surgery is deep to the peritoneum, such as a bowel resection, there is usually a component of deep visceral pain in the first 24 hours after surgery, requiring the use of additional pain relief (Webster 2010). Advantages of rectus sheath catheters The advantages of using a rectus sheath catheter over epidural analgesia include reduced risk associated with insertion technique, reduced incidence of hypotension, fewer pieces of equipment attached to the patient and absence of motor block making mobilisation easier (Webster 2010, Parsons et al 2011). Beaussier et al (2007) have also shown improved sleep quality during the first two postoperative nights, reduced duration of gastric ileus and shortened duration of hospital stay. Rectus sheath catheters may also be used for critical care Layer of rectus sheath covering rectus abdominus Rectus sheath Rectus abdominus patients. This particular group of patients often need urgent surgery, may present with sepsis, clotting problems and can be haemodynamicaly unstable (Webster 2010). Disadvantages of rectus sheath catheters There are some risks associated with the use of rectus sheath catheters and these should be considered. Risks include bleeding, damage to local structures during insertion, infection and local anaesthetic systemic toxicity (Webster 2010). The clinical presentation of toxicity can be neurological, cardiac or both. Therefore, regular patient monitoring should be performed to detect complications. In addition, education of both nursing staff and patients regarding what neurological symptoms to report, for example, metallic taste, ringing in the ears, tingling around the lips and face or visual disturbance, will prompt early action to stop the infusion and call for help (Odera and Lyons 2010). Major blood vessels run through the posterior rectus sheath and it is possible to place the catheter or needle tip into these vessels accidently. Such placement may cause bleeding, haematoma or intravascular administration of local anaesthetic (Webster 2010). Careful use of ultrasound reduces this risk considerably. If a rectus sheath catheter is used to administer intermittent, manual boluses of local anaesthetic post-operatively, increased risk of infection occurs arising from frequent accessing of the sterile system (Webster 2010). It is the author s experience that, in some centres, intermittent boluses are administered six-hourly by nursing staff. The catheter may be left in place for four days, meaning the sterile system is accessed 16 times. The use of a pump connected to the catheters to provide a continuous infusion may reduce infection risk caused by frequent system access. Local anaesthetic toxicity is rare. However, it can be catastrophic. It is a consequence of high levels of local anaesthetic in systemic circulation. Symptoms range from mild (auditory changes, numbness around the mouth, metallic taste and agitation) to serious central nervous system effects (seizures, coma and respiratory arrest) or cardiovascular effects (hypertension, hypotension, tachycardia, bradycardia, ventricular arrhythmias and cardiac arrest) (Jeng et al 2010). Brief guidelines for treatment of local anaesthetic toxicity as recommended by the Association of Anaesthetists of Great Britain and Ireland (AAGBI) are summarised in Table 1 (Cave et al 2010). PETER LAMB Changing practice In 2012, rectus sheath catheter infusions were introduced by the author s trust for patients 40 june 18 :: vol 28 no 42 :: 2014 NURSING STANDARD / RCN PUBLISHING

5 undergoing colorectal and urological procedures using a single infusion pump to provide a continuous rate of 2mL of 0.15% bupivacaine per hour, with a facility for nursing staff members to administer a pre-set, 40mL bolus dose of 0.15% bupivacaine from the pump every five hours. Audit data have shown most bolus doses were given on time for the first two days, but then delayed doses were administered during days three and four, which had an effect on pain scores. A further audit is being undertaken to assess the extent of the problem. In 2012, Smiths Medical introduced the CADD-Solis Ambulatory Infusion Pump with programmed intermittent bolus (PIB) delivery (Figure 3). The pump has the potential to be set to deliver a continuous rate plus a programmed bolus at timed intervals, thereby reducing the need for nursing staff to administer the bolus dose. The pump is small and lightweight and can be carried easily in a small pouch, making patient mobilisation easier. The trust agreed to trial four pumps for colorectal and urology patients. The acute pain nurses collected audit data relating to 30 patients over an eight-month period between August 2012 and March Method Records from nursing and medical notes were used to collect data. The primary outcome measure was the maximum and average documented pain score in the first 48 hours following surgery, measured using 0 = no pain and 10 = worst pain. Additional data collected included type of surgery performed, anaesthetic technique (all catheters were sited by anaesthetists using ultrasound guidance), post-operative analgesia use, incidence of nausea and vomiting, mobility and complications. All patients received the standard rectus sheath catheter infusion prescription of bupivacaine 0.15% at a rate of 2mL/hour with a new CADD pump regimen of 35mL bolus delivered four-hourly (0.15% of bupivacaine is equal to 1.5mg/mL; the total daily dose of bupivacaine infused is 258mL, which equals 387mg). This programme was based on recommended maximum doses of local FIGURE 3 CADD-Solis Ambulatory Infusion Pump REPRODUCED WITH PERMISSION FROM SMITHS MEDICAL, ASD, INC. TABLE 1 Brief summary of guidelines for the treatment of local anaesthetic toxicity Recognition Immediate management Treatment (Adapted from Cave et al 2010) Recognition of the signs of severe toxicity (this can occur after local anaesthetic infusion has stopped): Alteration in mental state. Severe agitation or loss of consciousness. Cardiac arrhythmias. STOP LOCAL ANAESTHETIC INFUSION. CALL FOR HELP. Reassure the patient as best you can. Assess airway and administer 100% oxygen. Confirm intravenous access. Assess and manage cardiovascular status and seizures. IN CARDIAC ARREST Start cardiopulmonary resuscitation using standard protocols. Assess and manage arrhythmias. Give intralipid (see the Association of Anaesthetists of Great Britain and Ireland guidelines for guidance). WITHOUT CARDIAC ARREST Treat hypotension and/or arrhythmias. Consider intralipid. NURSING STANDARD / RCN PUBLISHING june 18 :: vol 28 no 42 ::

6 Art & science pain management anaesthetic. Literature on bupivacaine advises that the dose of 400mg in a 24-hour period is well tolerated in average-sized adults (Electronic Medicines Compendium 2014). Staff training Before the CADD-Solis Ambulatory Infusion Pump was used in practice, training sessions were arranged for staff members who were likely to be involved in this technique. This included anaesthetists and anaesthetic practitioners in theatres and nursing staff in recovery, staff members in the critical care unit and the three surgical wards that would be looking after the patients. The training session included background information on the type of block used, how pain relief is provided, setting up and management of the pump, documentation and patient monitoring, management of local anaesthetic toxicity and specific nursing care. Staff members were reassured that the acute pain service would be available to help with any problems setting up the pumps, for daily review of the patients and that out-of-hours anaesthetic staff members were available for advice if problems occurred. In addition, a training manual with support material was provided for each department and ward. Results Data were collected from 30 patients aged years. Twenty-one patients had urological procedures and nine had colorectal procedures. Twenty-four of the 30 patients had open laparotomy. Four were laparoscopic procedures converted to open and two laparoscopic-assisted procedures. All patients had a general anaesthetic. Ten patients had spinal opioids (dose range from mg diamorphine). An anaesthetist sited all catheters using ultrasound with no complications arising during the procedure. The results are summarised in Tables 2-4. In the post-operative period alongside the rectus sheath catheter infusion, patients received either intravenous PCA (morphine or oxycodone) or oral morphine or oxycodone. To compare opioid requirement, the doses have been calculated as equivalent to IV morphine (1mg IV oxycodone = 1mg IV morphine, and 10mg oral morphine = 3mg IV morphine). Over the 48-hour period, maximum pain scores ranged between mild (day 1, 21 patients, day 2, 25 patients) to moderate (day 1, 9 patients, day 2, 4 patients) with most patients reporting only mild pain (Table 2). Most patients required less than 25mg of morphine (day 1, 18 patients, day 2, 24 patients) (Table 3). A small patient TABLE 2 Average and maximum number of patients who experienced pain (n=30) Pain score Mild pain 0-3 Moderate pain 4-6 Severe pain 7-10 Average Maximum Average Maximum Average Maximum Day Day TABLE 3 Comparison of the range of morphine used in days 1 and 2 following surgery (n=30) Morphine range 0-25mg 26-50mg >50mg Day 1 18 patients 7 patients 5 patients Day 2 24 patients 4 patients 2 patients TABLE 4 Additional analgesia given, the incidence of nausea and vomiting reported and ability to sit out of bed on days 1 and 2 following surgery (n=30) Day 1 Day 2 Number of patients receiving regular paracetamol Number of patients receiving regular ibuprofen 9 8 Incidence of nausea and vomiting 7 6 Number of patients able to sit out of bed june 18 :: vol 28 no 42 :: 2014 NURSING STANDARD / RCN PUBLISHING

7 group required no, or minimal additional analgesia (day 1 and 2, 10 patients received between 0mg and 5mg morphine). This group of patients received spinal opioids intraoperatively, which may have relieved their initial visceral pain. Regular paracetamol and ibuprofen were administered to provide background analgesia during the first two days post-operatively. All patients received regular paracetamol, but a large proportion (21 patients) did not receive ibuprofen (Table 4). Acute renal failure caused by NSAIDs can occur post-operatively (Macintyre and Schug 2007). Caution regarding this phenomenon in the first hours may be the reason for fewer ibuprofen administrations (Macintyre and Schug 2007). The incidence of post-operative nausea and vomiting was low, occurring in only seven patients. One patient developed a gastric ileus. The data indicate that mobility was not impaired, as the majority of patients were able to sit out of bed from day 1 (Table 4). There were no incidents reported with using the pump and only one case of leakage from the catheter insertion sites was reported. Conclusion Surgical incisions cause tissue damage, which results in acute post-operative pain in the first few days after surgery. In some cases, this pain can be severe and can have serious consequences for patient recovery. The use of more effective analgesic techniques should help in providing better pain relief for both routine and emergency patients requiring abdominal surgery and, consequently, help to improve outcome and enhance recovery. The audit data presented demonstrates that the use of rectus sheath catheter infusions for post-operative pain management is safe and provides good pain relief. In addition, the CADD-Solis Ambulatory Infusion Pump with its novel PIB appears to be reliable and safe, is easy to use and does not hinder patient mobility. 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