Pain_Relief

Coventry University Faculty of Health and Life Sciences Diploma HE Paramedic Science January 2011 Cohort Module 227PM Paramedic Skills Development Across the Age Spectrum Student number 3787258 Fentanyl Verses Morphine Sulphate in A Road Traffic Collision Set Word Limit:2000 Word Count:2188 Submission Date:31/05/2011 The number of reported road accident casualties in Great Britain in 2009 were a total of 222,146 reported casualties of all severities, 4 per cent lower than in 2008. 2,222 people were killed, 12 per cent lower than in 2008, 24,690 were seriously injured (down 5 per cent) and 195,234 were slightly injured (down 4 per cent). The number of fatalities fell for almost all types of road user, with a fall of 16 per cent for car occupants, 13 per cent for pedestrians, 10 per cent for pedal cyclists and 4 per cent for motorcyclists (DOT, 2009) The aim of this essay is to compare and contrast the use of fentanyl and morphine as pre-hospital analgesia, although in the ambulance service the two main forms of analgesia for medium to severe pain are Entonox and morphine Sulphate (JRCALC., 2006) the gold standard is morphine sulphate (Jelinek 2000, 1247). Yet is there another analgesia that we could be using which could enhance the Paramedics toolbox, and if so what are the implications and overall efficacy of a possible different analgesia' You are called to a RTC (Road traffic Collision), 30 y/o male, collided with a tree, trapped by his legs in a vehicle in considerable pain. Approximately 30 minutes to release him, airway patent, respiratory rate 22 rpm, barely palpable radial pulse, 120 bpm Tachycardic, BP 95/50mmHg. Although paramedics abide by a code of practice, drug administration are governed by guidelines (JRCALC, 2006) that are outside of the remit for this essay, the author will be solely considering the difference between fentanyl and morphine, its route of administration, pharmacokinetics and pharmacodynamics of each drug in relation to the scenario given. According to Lord (2004) ‘It’s crucial for members of the health care team to acknowledge and support the expansion of the Paramedics role as a frontline pain manager’. (Lord 2004, 52) yet for paramedics to do this then surely as a profession the need for more rapid and effective methods to administer analgesia is needed' Surely we can’t only rely on I.V morphine as our main order of pain relief' Although morphine is considered the gold standard and is what all analgesics are rated against there are drawbacks and considerations for its use including administration, yet as a potential alternative fentanyl could certainly compliment the paramedic’s analgesic regime. In relation to our scenario we have a patient that is trapped within a vehicle in considerable pain yet is potentially heamodynamically unstable in which we could administer fluids to increase his systolic blood pressure however intravenous infusion although traditional now has less priority because of lack of evidence that benefit and not harm is being done (Coates & Davies 2002, 1135-8). We have in the Ambulance service two choices of analgesia before senior clinicians are sought, we could administer Entonox, however once that person is to be extricated and has to be boarded then self administration cannot be achieved, so morphine is our only line of defence for pain relief yet is contra-indicated for severe hypotension (JRCALC, 2006) so where do we stand' fentanyl however rarely causes a majorly significant histamine response unlike morphine which is more appropriate for heamodynamically unstable patients (Kogler, 2008, 10-12). Whilst fentanyl and morphine are both opiates they have differing routes of administration with fentanyl being I.V (intra-venous), S.C (sub-cutaneous), I.N (intra-nasal), T.D (trans-dermal) and OTM (oral trans-mucosal) lollipop. Administration routes for morphine being I.V (intra venous), S.C (sub-cutaneous), I.M (intra-muscular), P.O (per orally) and tablet form, however, due to the first pass mechanism morphine is less bio available by up to 60% when taken the P.O route (Simonsen et al 2006, 54-55) whereas fentanyl can be administered both parentally or enteraly yet without any major reduction in bioavailability due to liver metabolisation (Simonsen et al 2006, 53) and in the case of intra-nasal and mucosal lollipop both the administration routes and bioavailability of fentanyl could be a major advantage in prehospital care over morphine especially in the case of time critical patients and patients that have peripheral shutdown or clinicians are unable to access the patient to cannulate. Intranasal opiates have the clear theoretical advantage of providing rapid analgesia to patients where cannulation is undesirable or impossible. However, there is limited available evidence to suggest that intranasal fentanyl may provide similar analgesia to intravenous morphine in the emergency department further evidence from larger trials is still required (Carley 2010). Another point to consider regarding administration route is that due to the skills mix within the Ambulance Service if a double technician crew had to attend this job the current regime of analgesia available would prevent any pain relief over and above Entonox due to I.V access not being an available option until paramedic backup arrives increasing both patient and attending clinicians anxiety levels (Faddy & Garlick 2005:901-908) Due to the Lipophilic nature of fentanyl (Darwish et al 2007, 56-63) is the cause of such rapid onset of action when compared to morphine, with fentanyl having a distribution time of 1.7 minutes, redistribution of 13 minutes and terminal elimination half-life of 219 minutes (O,Donnel, 2005, 529). Morphine however is more hydrophilic in nature which means it doesn’t cross over as fast into the CNS (central nervous system) making the distribution time relatively long with a time frame of approximately 15 minutes from administration (Trescot et al, 2008) with a plasma half life between 2-3 hours after I.V injection which could have a greater chance of opioid overdose due to poor titration during treatment. Because of this it is important to remember that they are both opioids and so an antagonist agent such as naloxone hydrochloride (Narcan) must be available before administration for reversal of adverse effects (JRCALC 2006) yet even with this antagonist agent complications especially in the pre hospital setting and in relation to the scenario can occur especially where time is of the essence and serious side effects can have a momentous impact on patient care and can actually exacerbate the patient’s condition and prolong on scene time. Morphine and fentanyl fundamentally both act on the bodies opioid receptors as the primary method of action with pharmocodynamics being pretty similar between the two. Both fentanyl and morphine act as agonists that bind with specific receptor sites within the brain, the bodies endogenous (from within) opiate sites known as Sigma (responsible for delirium), Kappa (spinal level analgesia, central sedation zero respiratory depression) and Mu (analgesia, euphoria, respiratory depression). (Eaton 2004, 129) these sites in themselves are not the problem but the way in which the two drugs interact with them could be, specifically fentanyl stimulates the Mu receptor sites and delta receptor sites whereas Morphine interacts with Mu, Delta and Kappa receptor sites and in so doing may be the cause of some divergent pharmacodynamics when using the two types of analgesia (Rang, Dale, Ritter 1999, 593) even though this has been touted as true nobody can readily explain why and it has not been rigorously validated (Fleishman et al 2010, 167-175) yet this could be quite significant for the patient in our scenario because as stated the patient is bordering on hypotension where morphine is contraindicated yet even though fentanyl and morphine both act on Mu receptor sites, fentanyl has been clinically proven to rarely cause a significant histamine response (Taylor 2005), to the level that morphine will, the significance of which is that fentanyl has fewer adverse effects on the cardiovascular system and can be used in patients who are heamodynamically unstable unlike morphine which can cause severe hypotension.( Kogler, 2008, 10-12) Within the prehospital setting complications such as compromised airways are an unwanted situation and so anything that can be done to either neutralise or decrease the risk is certainly a positive intervention yet both morphine and fentanyl act on the Mu receptor sites (Trescot et al, 2008) which in turn can increase the risk of vomiting due to decrease in motility within the intestinal tract (movement by independent means) (Simonsen et al 2006, 280) yet of the two opiates in question Morphine appears to have a greater emetic activity than fentanyl (Fishman. 2009, 725) in relation to the scenario the effect of vomiting on the patient can cause the risk of increased inter-cranial pressure (Lambie et al,1999, 242) which could then in turn have a greater risk of further complications for the patient and possibly impact on vagal stimulation in so doing increasing blood pressure and pulse rate (McNarry 2004) so before any opioid is administered blood pressure should be monitored closely (JRCALC,2006). Fentanyl could certainly be considered as an alternative choice especially as the patient in question is an unknown quantity and although his airway is patent at present, things like kinetics of injury need to be taken into account (Sastry et al 2009). If any damage has been sustained by the abdominal area the contractions of the abdominal muscles associated with vomiting can cause further damage in an already damaged area which if unknown to the clinician in question, coupled with the patient not long ago consuming a meal, then vomiting could occur with the stomach contents leading to risks such as respiratory obstruction, pulmonary inflammation and aspiration pneumonia (Lambie et al, 1999, 242) an obvious complication could then be a severely compromised airway which as stated before, in the pre-hospital setting is undesirable at best, this could then lead to the contentious subject of pre-hospital intubation and the inherent risks associated (Deakin et al, 2010) not to mention the patients worsening condition. Another point is that within the ambulance service the only anti-emetic available to paramedics is Metacloprimide (JRCALC, 2006) which is not considered the best intervention. A study was performed regarding the efficacy of Metacloprimide where it was compared to the effects of a placebo and although this is not the subject for this essay the results regarding Metacloprimide were poor (Talbot-Stern 2000, 656). Fentanyl may be a likely drug to use for its anti- emetic qualities, Claxton et al in Toronto conducted a study with Fifty-eight patients undergoing ambulatory surgery were prospectively randomized to receive morphine or fentanyl for postoperative analgesia and studied in double-blind fashion and was found that the incidence of nausea and vomiting after discharge was higher with morphine, 59% vs. 24%, and the overall incidence of nausea and vomiting was also higher, 79% vs. 38%. Antiemetic therapy was required by 24% in the morphine group vs. 14% in the fentanyl group (NS). Other postoperative symptoms such as drowsiness and dizziness were comparable between the groups (Claxton., A.R., 1997, 509-14), although promising in nature for fentanyl this was a very small study and the author is inclined to believe that a larger and more comprehensive study would be in order. In the nature of pain relief morphine remains the most valuable analgesic and is the gold standard (Jelinek 2000, 1247) to which all other opioids are compared to, in relation to pain relief morphine gives a state of euphoria and mental detachment (BNF 60, 2010, 261) and also in prehospital care the same applies it is recognised as the ‘Gold Standard’ in pain relief however it does come with certain contra-indications (JRCALC, 2006), Children under 1 years of age Respiratory depression adult<10 Breaths P/m child<20 Breaths P/m) Hypotension, (actual <90mmHg sys adult, <80mmHg sys school child, <70mmHg sys pre-school child). Head injury with significant impaired consciousness(GCS<12) Phaeochromocytoma (tumour on adrenal gland) Hypersensitivity to Morphine Known severe renal or hepatic impairment Fentanyl is a potent synthetic narcotic agent with a rapid onset and short duration of action, surprisingly however for such a powerful analgesic fentanyl has few contraindications those of which are (Sinatra R., 2010. 132) the primary contraindication for the use of Fentanyl is a known or suspected allergy A relative contraindication to its use would be inability to reverse the analgesic effect in the event respiratory depression occurred. (naloxone hydrochloride however should be available at all times before administration of an opioid.) (JRCALC 2006) No one really knows why fentanyl has fewer contra-indicators to morphine but it must be remembered that both are opioids and that cautions for both drugs are relatively similar. Yet could it not be argued that due to the fewer contra indicators that fentanyl presents should it not be trialled within the UK Ambulance Services to establish if it has a place within the prehospital setting, especially if it is found to be suitable in an environment where additional backup and resourses are not always forthcoming and expedient, is it not also fair to say that a drug that is in operation within hospital emergency departments (Kogler et al 2008, 10-12) could be utilised in the Ambulance Service especially a drug that can give fast analgesia with few complications' Pain management as a topic is probably the most talked about subject within the prehospital arena but it is not the authors wish to try to dissuade the readers minds as to whether fentanyl is better than morphine or visa-versa but it is the authors intention to stimulate debate regarding possible alternatives to the current drug regime used within the Ambulance Service. The introduction of fentanyl into the prehospital setting should be the responsibility of the Medical Directors and administrators that will have to oversee and implement any change within a given system, even so it should certainly be considered as a possible addition to our current regime where Morphine is the only alternative until additional medical resources arrive as currently the Ambulance service has a skills mix that is not consistent throughout the service as a whole and the possible use of fentanyl especially intra-nasally or sublingually could help in addressing that dilemma.