دانلود رایگان ترجمه مقاله اثر اسپری موضعی وپوکولانت آلکان بر درد با لوله گذاری داخل وریدی – نشریه Bmj 2009

اثر اسپری موضعی وپوکولانت آلکان بر درد با لوله گذاری داخل وریدی در بیماران بخش اورژانس: کارآزمايی بالينی کنترل شده دوسوکور پلاسیبو

Effect of topical alkane vapocoolant spray on pain with intravenous cannulation in patients in emergency departments: randomised double blind placebo controlled trial

Abstract

Objective To assess the efficacy, acceptability, and safety of a topical alkane vapocoolant in reducing pain during intravenous cannulation in adults. Design Randomised double blind placebo controlled trial. Setting Emergency department of a metropolitan teaching hospital. Participants 201 adult patients (54% male), mean (SD) age 58.2 (19.5) years, who required intravenous cannulation. Interventions Less than 15 seconds before cannulation, the skin area was sprayed with either water (control, n=98) or vapocoolant (intervention, n=103), from a distance of 12 cm for 2 seconds. The intervention spray was a blend of propane, butane, and pentane. Main outcome measures Pain with cannulation and discomfort with spray, measured with a 100 mm visual analogue scale. Results Groups did not differ significantly in age, sex, indication for or site of cannulation, cannula size, or who cannulated the patient (P>0.05). Median (interquartile range) pain scores for cannulation in the control and intervention groups were 36 (19-51) and 12 (5-40) mm, respectively (P<0.001), and 59 (60%) and 33 (32%) reported pain scores ≥30 mm (P<0.001). Scores for spray discomfort also differed significantly (P<0.001) because of skewing to the right within the intervention group. The median discomfort scores, however, were 0 mm in both groups. Success rates for first cannulation attempt did not differ between groups (P=0.39). Thirty four (39%) and 62 (62%) patients said they would choose the spray they receivedfor analgesia in thefuture (P=0.002). Atfollow-up at five days, two patients in the intervention group reported transient skin redness. Conclusions Topical alkane vapocoolant spray is effective, acceptable, and safe in reducing pain with peripheral intravenous cannulation in adults in the emergency department.

1 Introduction

As about half of patients report moderate to severe pain with cannulation and anxiety before the procedure, administration of local anaesthetic might be justified.1 On a 100 mm visual analogue scale pain scores in untreated adults ranged from 24 mm to 38 mm.1-3 Intradermal injection of lidocaine is commonly used for analgesia.4 This effectively reduces pain2 3 by clinically important amounts.5 The injection itself, however, is painful,3 and, theoretically, there is an increased risk of needle stick injury. Additionally, reports are divided on whether local tissue distortion, caused by the injection, increases3 or has no effect on1 2 the rate of cannulation failure. Another strategy is the application of topical local anaesthetic. These agents must penetrate the stratum corneum barrier,6 7 which necessitates application times of at least 45 minutes for Emla (lidocaine 2.5% and prilocaine 2.5%)8 and 30 minutes for Ametop (4% tetracaine).9 In emergency departments, such application times are often unacceptable as immediate cannulation is often required. Less than half of medical and surgical doctors use local anaesthetic for insertion of large bore intravenous cannulas.10 Furthermore, for the most commonly used cannula (size 20 gauge), less than 20% of all doctors used any local anaesthetic.10 Another study reported that 35% of junior doctors had previously used local anaesthetic for cannulation but their current rate of use was only 6%.4 Topical vapocoolant sprays can produce immediate skin anaesthesia. Commonly used vapocoolants include ethyl chloride, fluorohydrocarbon, and alkane mixtures (butane, propane, and pentane). Alkane vapocoolant sprays are primarily used to provide rapid pain relief from acute muscular injuries. Rapid evaporation of the volatile liquid spray from the skin surface causes a drop in temperature and results in temporary interruption of pain sensation, possibly through desensitisation of pain receptors or activation of ion channels involved in pain transmission.11 Topical vapocoolant spray therefore offers a potentially convenient and effective anaesthetic for intravenous cannulation. Previous studies of vapocoolant sprays for reducing pain with intravenous cannulation in adults have shown inconsistent results. Four randomised controlled trials have been reported. Two showed ethyl chloride to be effective,2 3 while two others found ethyl chloride1 and fluorohydrocarbon,12 respectively, to be ineffective. Methods in these studies varied, including variation in cannula size, duration and distance of spray, small sample sizes, and lack of blinding. We assessed the efficacy, acceptability, and safety of a topical alkane vapocoolant spray for reducing pain with intravenous cannulation in adults by comparing its effects with a control (water) spray.

METHODS

Study design

Thetrialtook placefrom November 2007toMay 2008. It was a randomised double blind placebo controlled clinical trial set in a mixed (adult and paediatric) emergency department that treated about 55 000 patients a year. Patients were included if they were aged ≥18 and needed intravenous cannulation. Exclusion criteria were refusal to participate, inability to provide informed consent (non-English speaking, altered mental state, severe illness, urgent need for cannulation), moderate to severe discomfort or pain, skin disease associated with cold intolerance (such as Raynaud’s phenomenon), known allergy to spray contents, peripheral neuropathy or numbness, parenteral analgesia within the previous four hours, and the use of other local anaesthesia.

Recruitment

We enrolled a convenience sample comprising consecutive patients who met the entrance criteria during periods when the principal investigator was present in the emergency department (mainly 9 am to 5 pm on weekdays). The emergency department staff notified the principal investigator of patients who required cannulation. Patients who met the entrance criteria received a verbal and written explanation of the study and gave written consent to participate.

Randomisation

Each enrolled patient was then assigned the next sequentially ordered study pack. These contained all the documents for data collection and a sealed envelope containing a note that advised the group to which the patient had been randomised. Patients were block randomised (blocks of six) by an independent pharmacist using a computerised random number generator. Until after informed consent had been obtained, only the pharmacist knew the randomisation status. At that time, the principal investigator opened the sealed envelope and prepared to administer the assigned spray. The patients, their carers in the emergency department, and independent emergency department staff who collected outcome data were all blinded to the randomisation status.

Intervention and control sprays

The vapocoolant (intervention) spray was CO LD Spray, manufactured by DIFA Chemical Industries for Alpha First Aid Supplies. It is a propane, butane, and pentane blend, with an added fragrance, and is supplied in a standard(about 20 cm long, 250 g in weight) handheld pressurised spray can. It is registered with the Therapeutic Goods Administration, Australia, for the first aid treatment of muscular pain and other injuries. One 250 g can costs $A13.90 (£6, €7) and contains about 70 administrations. The control (placebo) spray was Evian Eau Minerale Naturelle, a pure water spray with hydrocarbon propellant. This product is used to provide a cooling mist for comfort during hot weather. It is also packed in a handheld pressurised spray can of about the same size as the intervention spray