burns 34 (2008) 929–934 available at www.sciencedirect.com journal homepage: www.elsevier.com/locate/burnsPatient controlled sedation using a standard protocol fordressing changes in burns: Patients’ preference, proceduraldetails and a preliminary safety evaluation§Andreas Nilsson a,*, Ingrid Steinvall b, Zoltan Bak b,c, Folke Sjoberg b,c,d ¨a Department of Anesthesiology and Intensive Care, Division of Perioperative Medicine, Linkoping University Hospital, ¨581 85 Linkoping, Sweden ¨b The Burn Unit, Department of Hand and Plastic Surgery, Linkoping University Hospital, 581 85 Linkoping, Sweden ¨ ¨c Department of Intensive Care, Linkoping University Hospital, 581 85 Linkoping, Sweden ¨ ¨d Faculty of Health Sciences, Department of Biomedicine and Surgery, Linkoping University Hospital, 581 85 Linkoping, Sweden ¨ ¨article info abstractArticle history: Background: Patient controlled sedation (PCS) enables patients to titrate doses of drugs byAccepted 10 April 2008 themselves during different procedures involving pain or discomfort. Methods: We studied it in a prospective crossover design using a ﬁxed protocol withoutKeywords: lockout time to examine it as an alternative method of sedation for changing dressings inAlfentanil burned patients. Eleven patients with >10% total burn surface area (TBSA) had theirAnesthesia dressings changed, starting with sedation by an anaesthetist (ACS). The second dressingBurns change was done with PCS (propofol/alfentanil) and the third time the patients had toPropofol choose ACS or PCS. During the procedures, data on cardiopulmonary variables, sedationPatient controlled sedation (bispectral index), pain intensity (VAS), procedural details, doses of drugs, and patients’Sedation preferences were collected to compare the two sedation techniques. Results: The study data indicated that wound care in burned patients is feasible with a standardized PCS protocol. The patients preferred PCS to ACS on the basis of self-control, and because they had less discomfort during the recovery period. Wound care was also considered adequate by the staff during PCS. No respiratory (respiratory rate/transcuta- neous PCO2) or cardiovascular (heart rate/blood pressure) adverse events were recorded at any time during any of the PCS procedures. The doses of propofol and alfentanil and BIS index decrease were less during PCS than ACS. Procedural pain was higher during PCS but lower after the procedure. Conclusion: We suggest that PCS using a standard protocol is an interesting alternative to anaesthetist-provided sedation during dressing changes. It seems effective, saves resources, is safe, and at same time is preferred by the patients. The strength of these conclusions is, however, hampered by the small size of this investigation and therefore further studies are warranted. # 2008 Elsevier Ltd and ISBI. All rights reserved. § ¨ The study was performed at the Burn Unit, Department of Hand and Plastic Surgery, Linkoping University Hospital, Ostergotland ¨ ¨County Council. * Corresponding author. Tel.: +46 13 22 1834; fax: +46 13 22 2836. E-mail address: email@example.com (A. Nilsson).0305-4179/$34.00 # 2008 Elsevier Ltd and ISBI. All rights reserved.doi:10.1016/j.burns.2008.04.002
930 burns 34 (2008) 929–9341. Introduction enrolled in a prospective exploratory study at the National Burn Centre at Linkoping University Hospital, Linkoping, ¨ ¨Patients with severe burns have severe pain and anxiety, Sweden.which have both psychological and physical effects for the Inclusion criteria were: need for analgesia and sedation forrecovery process . Pain for these patients is elicited not at least two consecutive dressing changes. Patients withonly from the trauma event, but is also the result of injures of more than 10% or more than 5% full thickness wasrepeated procedures, dressing changes and physiotherapy. asked to participate. Exclusion criteria were ASA III–V, burnedThese procedures are repeated, and often lead to appreci- hands (because of difﬁculties in using the PCS device) orable pain, and they emphasise the need for advanced difﬁculties in communication or understanding of the proce-strategies for the treatment of pain . Morphine, fentanyl, dure. Four patients entered the study but did not fulﬁl theand alfentanil are commonly used opioids that provide protocol because only one or two dressing changes werecontinuous, analgesia during and after the operation and needed that required analgesia and sedation.the intravenous route is often preferred for rapid pain The study was designed as a single-centre, single-case,control. Self-titration of morphine (patient controlled crossover, controlled study. Patients were their own controlanalgesia; PCA) has been suggested as an important group, because they started with dressing changes undertechnique to meet the increasing and high requirement sedation by an anaesthetist (ACS, FS or ZB; anesthesiologistsfor opioids . Successful pain management requires that with 10 years experience of burn care) using routine sedatingpain is regularly assessed and its intensity evaluated as, for techniques. While the patient breathed oxygen and air,example by a visual analogical scale (VAS), and adequate sedation and analgesia were accomplished with intermittent,pain relief must be provided accordingly . Wound care intravenous propofol (Propofol-1Lipuro 10 mg/ml, Braun) andand dressing changes are associated not only with pain, but fentanyl (Fentanyl1 0.05 mg/ml, Braun). The second dressingwith factors that are also known to affect the experience of change was done using PCS as described below. At the thirdpain such as anxiety and loss of self-control. The ther- dressing change the patients were asked to choose one of theapeutic challenge is to ﬁnd methods that control pain and two techniques.relieve anxiety and at the same time avoid over-sedation During the sedation procedures a protocol was used toand a delayed recovery . collect cardiopulmonary data (heart rate, non-invasive blood Patient controlled sedation (PCS) has received increasing pressure, saturation, and respiratory rate). Transcutaneousinterest when it has been used to improve the conditions of PCO2 were collected using TCM3—TINA (Radiometer, Copen-patients having painful or unpleasant procedures such as hagen, Denmark). Intensity of pain was assessed using a 11-lithotripsy, colonoscopy, or dental procedures [5–7]. It is point visual analogue scale (VAS) when patients were able toimportant also to others that the patient controlled sedation answer during the procedure, after ﬁnishing the dressingtechnique has been used in these settings (lithotripsy, changes, and 10 min later. Complications were recorded,dental, colonoscopy) without anesthesia-trained personnel. whether it was possible to treat the wounds adequately (yesPresently, in clinical practice at our hospital, lithotripsy is or no), and the duration of treatment. The bispectral (BIS)done using a propofol-based PCS technique without index was monitored using the A-2000 BISTM system (Aspectanesthesia-trained personnel. The procedure is based on Medical Systems, Natick, MA, USA). The recording of all theseEuropean Guidelines for sedation and/or analgesia by non- variables started before the onset of sedation and every 3 minanaesthesiology doctors . In patients with burns we are during the procedure, and up to 30 min afterwards. If a loweraware of only one dose-ﬁnding study that attempted to use BIS index appeared on the display between measurementit as an alternative to traditional ways of giving analgesics points, the lowest observed index was recorded. Within 2 h ofand sedatives . completion of the dressing change, each patient was asked The present study was designed to compare PCS, based on a about how they experienced the sedation and the awakeningstandard protocol, with routine sedation provided by anaes- from it.thetists, to assess the feasibility of PCS for adequate dressingchanges, and also to assess patients’ preferences. Close 2.2. Patient controlled sedationsurveillance of respiratory (respiratory rate/transcutaneouslyassessed PCO2) and cardiovascular (heart rate/mean arterial One hour before the dressing change all patients were givenpressure) data were measured as an estimate of safety, as the their regular daytime analgesics. These comprised: acetami-aim is to, in the future and after further reﬁnement, to nophen (Panodil1 1 g, GlaxoSmithKline Healthcare) and aimplement this strategy in the care of patients with burns long-acting opioid, Oxycodone (Oxycontin1 between 5 andwithout using speciﬁcally trained anaesthesia personnel. 40 mg). Before the start of the procedure or the anticipated pain the patients were asked to give sedation or analgesia by the PCS device whenever they felt pain or anxiety. Anticipated2. Patients and methods painful events were predicted during the procedure and conveyed to the patients so that they could prepare them-2.1. Study overview selves by giving analgesia and sedation. Propofol, 20 mg/ml (Propofol-1Lipuro 20 mg/ml, Braun,After approval from the local ethics committee and informed Sweden) and alfentanil 0.5 mg/ml (Rapifen1 0.05 mg/ml,consent of the patients, 11 patients with ASA I or II scores with Janssen-Cilag, Sweden) were mixed to 14.8 mg/ml of propofolburns exceeding 10% total burn surface area (TBSA) were and 0.13 mg/ml of alfentanil in the ﬁnal solution. A bag
burns 34 (2008) 929–934 931 Table 1 – Details of the patients Patient TBSA Age ACS PCS Time Propofol Morphine Time Propofol Morphine 1 15 74 64 325 10 74 153 10 2 35 32 69 500 40 85 282 18 3 12 51 91 480 20 52 140 9 4 12 82 33 170 10 50 89 5 5 15 67 81 234 10 62 195 12 6 18 23 130 632 25 60 271 17 7 16 77 82 320 15 113 191 12 8 10 68 65 395 15 50 164 10 9 8 62 44 412 15 56 102 6 10 19 59 56 490 20 78 173 11 11 20 38 47 385 25 63 369 23 Mean 16.4 57.5 69.3* 394.8** 18.6*** 67.5* 193.5** 12.1*** S.D. 7.2 19.3 26.7 130.7 9.0 19.0 83.5 5.3 ACS = anaesthetist controlled sedation; PCS = patient controlled sedation. The doses of propofol and alfentanil were given during ACS and the ﬁrst PCS. Values as mean and standard deviation (S.D.). Doses in milligrams and time in min. Total burned surface area (TBSA). *P = 0.859 (NS); **P = 0.003; ***P = 0.007. Statistical differences are shown between propofol and morphine.containing the mixture was connected to an electromecha- 3. Resultsnical pump (Graseby 9300 PCS, Graseby Medical Ltd., Watford,UK). Each time the button was pushed, the patient received 3.1. Details of patients (Table 1)0.3 ml of the mixture, equivalent to 4.44 mg propofol and0.039 mg alfentanil. No lockout period was used, which All the patients started the study with ACS followed by at leastresulted in a quantity of 22.2 mg propofol and 0.20 mg two PCS. Ten of the 11 patients preferred to continue dressingalfentanil possible to give in 1 min. changes using PCS after the ﬁrst ACS and PCS. One patient was For comparison and calculations the analgesic doses that of indifferent to the techniques but ﬁnally chose PCS.alfentanil was multiplied by a factor of 7, resulting inequipotent doses of morphine. Doses of fentanyl were multi- 3.2. Cardiopulmonary and surveillance dataplied by the factor of 100 . (Fig. 1 and Table 2)2.3. Data analysis and statistics Differences were found for SpO2, BIS, and transcutaneous PCO2, between ACS and PCS. PCS gave higher mean SpO2Data are presented as either mean (S.D.) or median (inter- concentrations, but lower PCO2, and less sedation according toquartile range). For the statistical analysis we used Statis- BIS monitoring.tica1 Version 6.1 (Stat Soft, Inc., Tulsa, USA). To assess During ACS there was a slight decrease in saturation (<90%)differences between groups we used the Wilcoxon Matched in two cases, the lowest respiratory rate was 8, and a lowestPairs Test. Changes over time in surveillance data between BIS index was 48. Blood pressure (MAP) was reduced duringACS and all PCS procedures were evaluated by repeated both techniques, the lowest values being between 50 and 68%measures ANOVA. Values of P < 0.05 were accepted as of baseline. Equivalent data during PCS showed no saturationsigniﬁcant. value lower than 94% and no respiratory rate less than 10. The Table 2 – Cardiopulmonary data and sedation data during ACS and PCS ACS PCS Statistical differences (P) Mean (S.D.) Min–Max Mean (S.D.) Min–Max SpO2, % 98 (3) 84–100 99 (2) 94–100 0.032 RR 14 (2) 8–17 16 (5) 10–30 0.707 PtcCO2 (kPa) 5.3 (0.4) 4.5–6.2 5.2 (0.5) 4.0–6.2 0.004 BIS index 84 (11) 48–99 93 (5) 67–99 0.027 HR 80 (11) 56–118 80 (11) 65–102 0.686 MAP (mmHg) 70 (15) 33–110 83 (11) 58–115 0.663 ACS = anaesthetist controlled sedation; PCS = patient controlled sedation. Values as mean and standard deviation (S.D.). Lowest and highest values recorded are presented as Min and Max. RR = respiratory rate, PtcCO2 = transcutaneous carbon dioxide, BIS index = bispectral index, HR = heart rate and MAP = mean arterial pressure.
932 burns 34 (2008) 929–934 Fig. 3 – Capacity of the pump in comparison with the patients with the highest demands. The doses are presented accumulated from start to the last received dose. Time (min) is from start.Fig. 1 – BIS index during ACS (sedation controlled byanaesthetist) and patient controlled sedation (PCS). given the doses. The capacity of the pump in relation to the patients with high dose demands is shown in Fig. 3.lowest MAP recordings were within 60 and 96% of baseline. 3.4. Procedure rating by personnelReduction in the BIS index also occurred during PCS with sixrecordings less than 80. After dressing changes, wound care personnel said that in all cases, during ACS and PCS, sedation was adequate and, wound3.3. Amount of drug given (Table 1 and Fig. 2) care conditions was good. Two surgeons indicated, however, that cleansing of the wounds could have been better on twoDuring PCS all patient requested lower doses of propofol and occasions during PCS.morphine (193.5 (83.5) and 12.1 (5.3) mg mean (S.D.)) than theywere given by the anaesthetist during ACS (394.8 (130.7) and 3.5. Pain ratings (Table 3)18.6 (9.0) mg). There was no difference in duration ofprocedure between PCS (67.5 (19.0) min) and ACS (69.3 The highest mean (S.D.) pain ratings recorded, during wound(26.7) min). treatment were greater for PCS (4.9 (2.4)) than for ACS (1.5 During PCS procedures, four patients had a third or less of (1,0)). Immediately and 10 min after dressing changes therethe required doses. The remaining seven patients had more were no differences.than 40% of required doses. Two of the four patients given lessthan a third of the doses given were not satisﬁed with thecapacity of the pump, although PCS overall was preferred. The 4. Discussionnine remaining patients were satisﬁed with how they were The new ﬁnding of this study is that PCS, using a standard technique with a ﬁxed protocol comprising the drugs propofol and alfentanil, can be used successfully as an alternative to ACS for wound care in burned patients. When patients chose between PCS and ACS, they chose PCS and truly preferred being in charge of their sedation instead of relying on somebody else. Although comparable data are lacking for burns, previous studies indicated a preference for PCS during other painful or unpleasant procedures [6,7]. A sense of control, together with a more rapid and less unpleasant recovery, together with the remaining possibility of deeper sedation if necessary were reasons given for the choice of PCS in the present study. 4.1. The procedure and pain With a patient who can communicate, those who are caringFig. 2 – Doses of propofol given by anaesthetist (ACS) for the wounds informed them if unpleasant or painfulcompared with the doses requested by the patients (PCS) moments were to be expected, which gives them time to giveduring the first PCS. the sedation and analgesia properly as described previously
burns 34 (2008) 929–934 933 Table 3 – Intensity of pain evaluated with visual analogue scale (VAS) Patient ACS PCS VAS max VAS min 0 VAS min 10 VAS max VAS min 0 VAS min 10 1 2 4 4 5 3 0 2 0 7 3 8 5 3 3 0 4 1 4 1 1 4 0 0 0 1 0 0 5 2 0 0 3 0 0 6 2 3 1 6 1 1 7 2 0 0 3 0 0 8 2 6 3 8 4 2 9 3 2 2 5 4 2 10 2 2 2 3 3 1 11 1 1 0 8 2 0 Mean 1.45* 2.64** 1.45*** 4.91* 2.09** 0.91*** S.D. 1.04 2.42 1.44 2.39 1.81 1.04 ACS = anaesthetist controlled sedation; PCS = patient controlled sedation. Values as mean and standard deviation (S.D.). Maximum pain score (VAS max in table) represent highest pain experienced during changing dressings and VAS min 0 is the pain intensity immediate after treatment. 10 min after dressing change pain intensity was again asked for (VAS min 10). *P = 0.003; **P = 0.234; ***P = 0.109.. As this was the ﬁrst series of PCS in this unit, the procedure present sedation. PCS itself is a factor in the satisfactionmight be reﬁned further as personnel get more acquainted among patients having cataract surgery, whether they did usewith the technique. We noticed that although special the pump with propofol or not  which in some way mayemphasis was placed on preparing the patients and predicting contribute to acceptance of the pain recorded in our study.painful events, this was at times missed and may togetherwith the sometimes impatient behaviour of the personnel 4.2. Safetyexplain the intermittently high VAS scores recorded duringcare of the wound and PCS. Astonishingly, despite the high Despite the fact that this study used propofol and alfentanil inVAS reported, it did not seem to affect the patients overall concentrations higher than evaluated previously [6,7,11,12]judgement of the technique. To optimise the procedure, and a device without a lock out time, PCS was accomplishedtherefore, further training may lead to less pain without the without extreme values in cardiopulmonary or BIS data. Theneed to change the doses of any drugs. The ﬁnding that the patients were monitored closely and were given supplemen-length of the procedures done by ACS and PCS did not differ tary oxygen and it is therefore unlikely that any adversealso suggests that PCS was adequate. reaction has been overlooked. In all, we recorded no single We made an interesting, new discovery during this trial. In value that indicated compromise of breathing or circulation.all patients verbal complaints of pain (with corresponding The fact that the corresponding decrease in the BIS index washigher VAS scores) were not always accompanied by pressure also minor supports this further. One must, however, beon the button to release the drug. There seemed to be cautious about the strength of this conclusion, as the numbercognitive dysfunction with the present drugs and protocol of patients was small.where, despite patients verbally complaining of pain, they The smaller amounts of analgesic and sedative used in thewere unable to process that into the action of providing study is probably the explanation for there being fewerthemselves with more of the drug. No extra doses were given symptoms of sedation after the procedure, which alsoby any bystander. explains the lack of effects on circulation and breathing. The high scores for pain recorded, and which seemunreasonably high, argues for more analgesic. This could 4.3. Sedation effectstheoretically be accomplished either by increasing the dose ofalfentanil given by PCS or by the supplementation of a longer- BIS monitoring was used to acquire objective data about theacting analgesic at the start of the procedure. This must to be state of sedation, instead of using sedation scales, which oftenexamined further. We must point out that not a single patient involve some interactivity with the patient . BIS indexesreached the maximum capacity of the pump; however, at the were collected during the procedure with no major distur-same time it is difﬁcult to give the maximum dose as there is a bances. The position of the patient’s head must be still andhidden lockout time during which the pump delivers a dose controlled as the BIS monitor detects muscular movement,already requested. An alternative is to increase the volume of and the signal quality may then be affected. We had few suchalfentanil, but that will only be achieved with less propofol, problems. BIS monitoring has been evaluated with propofolwhich will result in reduced sedation (given that the Graseby sedation and is a good predictor of the level of sedation .pump as presently sold commercially delivers only a ﬁxed However, there is a lag time between decreasing values andmaximum volume). As far as we know patients appreciate the the outcome of an observer’s assessment . As the purpose
934 burns 34 (2008) 929–934was not to delineate minor changes but rather to establish work. This study is performed on clinical basis of the Burnsedation levels, mainly for the group using PCS, we do not Unit, with no external inﬂuence.think that this has an impact on the interpretation of ourresults. As for PCS, few values were recorded below 80%, referenceswhich is similar to the ﬁndings made by Coimbra et al. . Thelowest values were present during ACS, which has been acommon ﬁnding by other authors who compared ASC and PCS ´  Latarjet J, Choiniere M. Pain in burn patients. Burnssuch as in, colonoscopy . In that study the corresponding 1995;21:344–8.ﬁgures were 58 (ACS) and 71 (ACS), respectively.  Ashburn M. Burn pain: the management of procedure- related pain. J Burn Care Rehabil 1995;16:365–71.4.4. Other issues  MacLennan N, Heimbach D, Cullen B. Anesthesia for major thermal injury. Anesthesiology 1998;89:749–70.There are some other issues of importance that should be  Jonsson CE, Holmsten A, Dahlstrom L, Jonsson K. ¨discussed. Background pain in burn patients: routine measurement and recording of pain intensity in a burn unit. Burns Firstly, when we compare PCS and ACS we must 1998;24:448–54.emphasise that the present standard in Sweden is to use  Alhashemi JA, Kaki AM. Anesthesiologist-controlled versusACS for patients with major burns. We know that inter- patient-controlled propofol sedation for shockwavenationally many units do their dressings with no anaesthetist lithotripsy. Can J Anaesth 2006;53:449–55.support. We think that this argues for PCS as an interesting  Roseveare C, Seavell C, Patel P, Crisswell J, Kimble J, Jones C,alternative to the present procedure, in which anaesthetic et al. Patient-controlled sedation and analgesia, usingpersonnel are required, and it also may explain why patients propofol and alfentanil, during colonoscopy: a prospective randomized controlled trial. Endoscopy 1998;30:768–73.accept the procedure to such a large extent with not much  Oei-Lim VLB, Kalkman CJ, Makkes PC, Ooms WG. Patient-sedation. The PCS technique would certainly reduce con- controlled versus anesthesiologist-controlled conscioussumption of resource. sedation with propofol for dental treatment in anxious For PCS in the present study we used a push-button device, patients. Anesth Analg 1998;86:967–72.which made it difﬁcult to recruit patients with burnt hands.  Knape JTA, Adriaensen H, van Aken H, Blunnie WP,These are common among our patients . Several candi- Carlsson C, Dupont M, et al. Guidelines for sedation and/ordates for the investigation were also excluded for this reason. analgesia by non-anaesthesiology doctors. Eur J Anaesthesiol 2007;24:563–7.There are, however, other techniques that could be tried for ´  Coimbra C, Choiniere M, Hemmerling TM. Patient-these patients. controlled sedation using propofol for dressing changes in The study was not blind; unfortunately this is not possible burn patients: a dose-ﬁnding study. Anesth Analgwith these techniques. We claimed that we used ‘‘true PCS’’, as 2003;97:839–42.no ‘‘lockout’’ time was used. This is not completely true as in  Wood M, Alastair JJ. Drugs and anesthesia: pharmacologypractice there is a lockout time when the pump is giving the for anesthesiologist, 2nd ed., Williams & Williams; 1990.  Herrick IA, Gelb AW, Nichols B, Kirkby T. Patient-controlledactual dose. This time is in the range of 15 s, and may explain propofol sedation for elderly patients: safety and patientthe discrepancy between the doses requested and the doses attitude toward control. Can J Anaesth 1996;43:1014–8.delivered.  Sim KM, Hwang NC, Chan YW, Sean CS. Use of patient- In conclusion, PCS as presented in this study using a ﬁxed controlled analgesia with alfentanil for burns dressingprotocol appears an interesting alternative to ACS for dressing procedures: a preliminary report of ﬁve patients. Burnschanges in serious burns. The patients chose PCS, and 1996;22:238–41.preferred it because they had better control and less sedation  Schraag S, Bothner U, Gajraj R, Kenny GN, Georgieff M. The performance of electroencephalogram bispectral index andafter the procedure despite having less sedation during it and auditory evoked potential index to predict loss ofmore pain. consciousness during propofol infusion. Anesth Analg 1999;89:1311–5.  Chen SC, Rex DK. An initial investigation of bispectralConﬂict of interest monitoring as an adjunct to nurse-administered propofol sedation for colonoscopy. Am J Gastroenterol 2004;99:1081–6.None of the authors have any ﬁnancial or personal relation-  Smith MA, Munster AM, Spence RJ. Burns of the hand and upper limb—a review. Burns 1998;24:493–505.ship with people or organizations that could inﬂuence this