Surgical Pain Relief: Multimodal Analgesia And Paracetamol

INTRODUCTION

As a nurse on a surgical ward dealing with a diversity of operating procedures it is important to understand the effects of surgical pain, as pain intensity and control is an integral part of the nursing duties. Layzell (2008) argues that pain management for postoperative patients should be a priority for all healthcare professionals. Furthermore having a say in how medications are administered but not prescribing drugs also means that it is essential to have an understanding of pharmacology. This ensures that informed discussions can talk place with the medical officer when it is felt that pain relief for a patient requires review. Additionally this enables the right balance of pain relief to be administered to minimise distress for the patient throughout their surgical journey. According to Lucas (2008) the benefits and adverse effects of the different types of analgesia also need to be considered when treating postoperative pain.

Pain is a complex phenomenon that is difficult to define. The most general definition used was published by the International Association For The Study Of Pain (IASP) in 1979 and refers to pain as an ‘unpleasant, sensory and emotional experience arising from actual or potential tissue damage or described in terms of such damage’ (IASP 2010). Pain is also subjective and the intensity can only be experienced by the sufferer (Mann and Carr 2006). Neurophysiology there are three types of pain receptors communicating pain signals through nociceptors or pain fibres (Mann and Carr 2006). These receptors can be found in ‘the skin, surfaces of the joints, periosteum (the specialised lining around the bone), arterial walls and certain structures in the skull’, although the brain itself does not have any of these receptors (Mann and Carr 2006, p3).

Each receptor reacts to a different stimulus. The mechanical receptor to touch, thermal to heat or cold and chemical to products present in the body that are released after trauma causing inflammation and increased sensitivity at the wound site (Mann and Carr 2006). The chemical receptors also react to chemicals introduced into the body (Mann and Carr 2006). The nociceptors are the sensory instruments that transmit pain signals through sensory nerve fibres to the dorsal horn of the spinal cord and into the brain (Mann and Carr 2006). There are three types of nerve fibres: A-delta responds to mechanical or thermal sensations, C fibres also known as polymodal because they respond to mechanical, thermal and chemical influences and A‑beta fibres which occur in the skin, reacts to touch but does not transmit pain sensations (Mann and Carr 2006).

Psychologically pain can induce fear, anxiety, anger, frustration and also a sense of helplessness may be experience from being unable to physically control the intensity of the pain being felt (Rothrock et. al. 2007).

Physiologically pain can reduce the functions of the immune system whilst increasing the potential for wound and chest infections as well as impairing the wound healing processes (Middleton 2003, Pudner and Ramsden 2010). Pain also induces vomiting, increases the workload of the cardiovascular and gastrointestinal systems, decreases lung capacity and can also reduce physical mobility (Middleton 2003, Rothrock et. al. 2007).

Traditionally following surgery, a single opioid drug such as morphine is used, depending on the type of surgery performed, for moderate to severe or acute pain (Shorten et. al. 2006).

It is argued that patients who receive this mono‑therapy would prefer to be treated with non­â€‘opioid remedies (Shorten et. al. 2006). According to Mann and Carr (2006) using the mono‑therapy method only targets one pain pathway and although morphine is considered the gold standard it tends to have many adverse effects. These include a 0.2% risk of respiratory depression, sedation, urinary retention, nausea and vomiting which affects around 30% of patients, itching or pruritus, hypotension or low blood pressure plus confusion and hallucinations in the elderly (Mann and Carr 2006, Rothrock et. al. 2007, Manley and Bellman 1999). Some of these side effects are controlled with anti‑emetics for sickness and anti‑histamines for pruritus (Rothrock et. al. 2007).

Combinational drug therapy began in the 1950’s (Michielsen 2007). Since then there has been increasing developments in establishing opiate sparing analgesic regimes with fewer side effects for surgical pain (Shorten et. al. 2006). Painkillers such as paracetamol (acetaminophen) can be combined with drugs from the codeine group, tramadol and non-steroidal anti‑inflammatory drugs (NSAIDs) as part of a multimodal regime (Manley and Bellman 1999). This allows for lower doses of individual drugs to be given, reducing the severity of adverse events and targeting more than one pain pathway as each drug has a different mechanism of action (Shorten et. al. 2006).

Paracetamol is a universal drug that is generally well tolerated but its mechanisms are not fully understood (Mann and Carr 2006). There are only mild to rare reported occurrences of side effects such as skin rashes and other allergic reactions (Manley and Bellman 1999).

Paracetamol, a member of the non-opioid group is one of ‘oldest known synthetic analgesic and antipyretic drugs’ (Manley and Bellman 1999, p470). Being also an antipyretic paracetamol has the ability to reduce fever temperature (Pudner and Ramsden 2010). It can be administered orally, rectally or intravenously in the form of a prodrug known as perfalgan or propacetamol (Manley and Bellman 1999, Royal Pharmaceutical Society of Great Britain 2007). Prodrugs are treatments that need to be broken down in the body before they become active (MedicineNet 2010). It is suggested that paracetamol should be used as part of a multimodal regime for surgical patients experiencing mild to moderate pain (Pudner and Ramsden 2010). Multimodal treatments involve combining drugs to form a compound in order to increase pain relief and reduce opioid adverse effect (Shorten et. al 2006, Manley and Bellman 1999, Pudner and Ramsden 2010). These combinational drugs are regulated by the Medicines and Healthcare Products Regulatory Agency (MHRA) and European Medicines Evaluation Agency (EMEA) and only a limited number has been approved (Shorten et. al 2006, Department of Health 2010). ‘Pharmaceutical companies have also introduced several fixed‑dose‑combinations’ such as co‑codamol a combination of codeine phosphate, a weak opioid and paracetamol as well as co‑dydramol a compound of dihydrocodeine and paracetamol (Shorten et. al 2006, p185). The main side effect of these codeine products is constipation, which can be remedied with a mild laxative (Manley and Bellman 1999).

Tramadol, another weak opioid can also be combined with paracetamol (Manley and Bellman 1999). The side effects of tramadol include minimal respiratory depression, nausea, vomiting, dizziness, headache and sweating (Manley and Bellman 1999).

Using this drug appears to defeat the object of reducing opiate contraindications but the combination is generally well tolerated and effective for moderate to severe pain (Shorten et. al. 2006). Rothrock et. al (2007) argues that combining NSAIDs with opioid drugs effectively reduces opioid usage by 20-40%. However increased postoperative bleeding and the chances of developing gastrointestinal ulcers cause NSAIDs to be used sparingly for surgical patients ((Rothrock et. al. 2007).

The Human Rights Act 1998 states that ethically it is the duty of all healthcare staff to ensure that patients are protected from any form of ‘torture, inhuman and degrading treatment and punishment’ (Office of Public Sector Information 1998, Article 3). Nurses are also responsible for their actions and as such must be able to justify decisions made or omissions which affect the well‑being of a patient (Nursing and Midwifery Council 2008). From a surgical nursing perspective this means it is imperative to ensure patients receive good pain management following their operation. However according to a recent study by Dolin, Cashman and Bland (2002) one in five patients still report severe postoperative pain. Manley and Bellman (1999) suggest patients commonly believe that pain is acceptable following surgery. While Pudner and Ramsden (2010) argue that postoperative pain should be controlled and patients should not expect or see pain as inevitable.

This literature review aims to firstly evaluate current research and evidence in relation to the use of paracetamol as one part of a multimodal analgesia regime for surgical pain relief. Secondly to use the results to make recommendations for standardising multimodal pain control for postoperative patients and re-educate staff on the importance of effective pain management.

METHODOLOGY

Search Criteria

For this literature review an advanced search was carried out over the internet. The health and medical sciences specific databases of Cumulative Index to Nursing and Allied Health Literature (CINAHL), Medical Literature Online (MEDLINE), Cochrane Library and Internurse.com were explored (Thomas 2000). CINAHL includes full text and is the most relevant source of information for nursing while MEDLINE ‘focuses on life sciences and is produced by the National Library of Medicine’ (LoBiondo-Wood 2010, p68). The Cochrane Library holds a collection of systematic reviews and Internurse.com has journal articles written by nurses (LoBiondo-Wood 2010, p68). The Cochrane Library was used to determine if any critical reviews had previously been carried out on the subject of paracetamol being used as part of a multimodal regime for postoperative patients. Only 4 papers were found. Internurse.com was exploited for articles containing current knowledge on the use of multimodal therapy for surgical patients. These editorials were utilised within the introduction.

The keywords or inclusion criteria for the literature search included paracetamol in the title while the words surgical and post operative were left optional to increase the depth of the search. Truncation or wildcards were employed to make the search more sensitive and specific to the topic being researched as follows: surgical – surg* and post operative – post op* (Gerrish, and Lacey 2006). The search mode was set to Boolean which ‘defines the relationships between words or groups of words in a literature search (LoBiondo-Wood 2010). This process involved using the word ‘AND’ before the truncated words ‘surg*’ and ‘post op*.

The date time frame was also limited from 2000 to 2010 to ensure that the studies were up to date and relevant to present day policies and procedures for pain control (LoBiondo-Wood 2010). Restrictions were also placed to only include papers that were based on humans, research papers and in the English language. Humans were selected as experiments on animals due to their biological makeup was not considered to be relevant to controlling postoperative pain in human beings. As this is a literature review it was appropriate to only select research papers for analysis. Language was also deemed to be significant as finances and the time schedule to complete the review did not allow for interpretation of the papers from other Dialects. Expanders were included to find papers that had related words and for the search to be carried out within the full text of the articles.

Review

8 papers resulted from the above search criteria. These were then screened using inclusion criteria, the titles and abstracts to determine their relevance to relieving surgical pain with multimodal analgesia therapy. The inclusion criteria was trials that included patients who had received paracetamol (acetaminophen) postoperatively, trials that included multimodal therapy, papers that were published within the last 10 years, subjects who were adults as my surgical setting only treats patients over the age of 18 and within a hospital environment. Exclusion criteria were trials that involved animals or children as discussed earlier. The types of interventions could include any routes for drug administration as paracetamol can be administered via intravenous, oral or rectal modes.

One paper was excluded from the review at this point as it was a mono‑therapy trial for paracetamol. The remaining 7 papers met with the inclusion criteria and were scored for methodological quality using a critical appraisal skills programme (CASP) containing 10 questions {{488 Public Health Resource Unit (PHRU) 2007}}. The questions were answered ‘yes’, ‘no’ or ‘can’t tell’ for each paper. Using a tool provides a way of systematically appraising what is published and filtering through papers to determine their relevance and accuracy {{427 Crookes, P. and Davies, S. 2004}}.