1. burns 34 (2008) 929–934
available at www.sciencedirect.com
journal homepage: www.elsevier.com/locate/burns
Patient controlled sedation using a standard protocol for
dressing changes in burns: Patients’ preference, procedural
details 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 abstract
Article history: Background: Patient controlled sedation (PCS) enables patients to titrate doses of drugs by
Accepted 10 April 2008 themselves during different procedures involving pain or discomfort.
Methods: We studied it in a prospective crossover design using a fixed protocol without
Keywords: lockout time to examine it as an alternative method of sedation for changing dressings in
Alfentanil burned patients. Eleven patients with >10% total burn surface area (TBSA) had their
Anesthesia dressings changed, starting with sedation by an anaesthetist (ACS). The second dressing
Burns change was done with PCS (propofol/alfentanil) and the third time the patients had to
Propofol choose ACS or PCS. During the procedures, data on cardiopulmonary variables, sedation
Patient 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: andreas.nilsson@lio.se (A. Nilsson).
0305-4179/$34.00 # 2008 Elsevier Ltd and ISBI. All rights reserved.
doi:10.1016/j.burns.2008.04.002

2. 930 burns 34 (2008) 929–934
1. 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 for
recovery process [1]. Pain for these patients is elicited not at least two consecutive dressing changes. Patients with
only from the trauma event, but is also the result of injures of more than 10% or more than 5% full thickness was
repeated procedures, dressing changes and physiotherapy. asked to participate. Exclusion criteria were ASA III–V, burned
These procedures are repeated, and often lead to appreci- hands (because of difficulties in using the PCS device) or
able pain, and they emphasise the need for advanced difficulties in communication or understanding of the proce-
strategies for the treatment of pain [2]. Morphine, fentanyl, dure. Four patients entered the study but did not fulfil the
and alfentanil are commonly used opioids that provide protocol because only one or two dressing changes were
continuous, 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 control
analgesia; PCA) has been suggested as an important group, because they started with dressing changes under
technique to meet the increasing and high requirement sedation by an anaesthetist (ACS, FS or ZB; anesthesiologists
for opioids [3]. Successful pain management requires that with 10 years experience of burn care) using routine sedating
pain 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 [4]. Wound care intravenous propofol (Propofol-1Lipuro 10 mg/ml, Braun) and
and dressing changes are associated not only with pain, but fentanyl (Fentanyl1 0.05 mg/ml, Braun). The second dressing
with factors that are also known to affect the experience of change was done using PCS as described below. At the third
pain such as anxiety and loss of self-control. The ther- dressing change the patients were asked to choose one of the
apeutic 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 to
and a delayed recovery [1]. collect cardiopulmonary data (heart rate, non-invasive blood
Patient controlled sedation (PCS) has received increasing pressure, saturation, and respiratory rate). Transcutaneous
interest 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 to
important also to others that the patient controlled sedation answer during the procedure, after finishing the dressing
technique 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 (yes
Presently, 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 (Aspect
anesthesia-trained personnel. The procedure is based on Medical Systems, Natick, MA, USA). The recording of all these
European Guidelines for sedation and/or analgesia by non- variables started before the onset of sedation and every 3 min
anaesthesiology doctors [8]. In patients with burns we are during the procedure, and up to 30 min afterwards. If a lower
aware of only one dose-finding study that attempted to use BIS index appeared on the display between measurement
it as an alternative to traditional ways of giving analgesics points, the lowest observed index was recorded. Within 2 h of
and sedatives [9]. 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 awakening
standard protocol, with routine sedation provided by anaes- from it.
thetists, to assess the feasibility of PCS for adequate dressing
changes, and also to assess patients’ preferences. Close 2.2. Patient controlled sedation
surveillance of respiratory (respiratory rate/transcutaneously
assessed PCO2) and cardiovascular (heart rate/mean arterial One hour before the dressing change all patients were given
pressure) 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 a
implement this strategy in the care of patients with burns long-acting opioid, Oxycodone (Oxycontin1 between 5 and
without 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. Anticipated
2. 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 propofol
burns exceeding 10% total burn surface area (TBSA) were and 0.13 mg/ml of alfentanil in the final solution. A bag

3. 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. Results
nical 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 and
0.039 mg alfentanil. No lockout period was used, which All the patients started the study with ACS followed by at least
resulted in a quantity of 22.2 mg propofol and 0.20 mg two PCS. Ten of the 11 patients preferred to continue dressing
alfentanil 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 in
equipotent doses of morphine. Doses of fentanyl were multi- 3.2. Cardiopulmonary and surveillance data
plied by the factor of 100 [10]. (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 SpO2
Data are presented as either mean (S.D.) or median (inter- concentrations, but lower PCO2, and less sedation according to
quartile 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 lowest
Pairs Test. Changes over time in surveillance data between BIS index was 48. Blood pressure (MAP) was reduced during
ACS 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 saturation
significant. 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.

4. 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 by
anaesthetist) 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 personnel
Reduction in the BIS index also occurred during PCS with six
recordings less than 80. After dressing changes, wound care personnel said that in all
cases, during ACS and PCS, sedation was adequate and, wound
3.3. 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 two
During 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 they
were 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 of
procedure 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 there
the required doses. The remaining seven patients had more were no differences.
than 40% of required doses. Two of the four patients given less
than a third of the doses given were not satisfied with the
capacity of the pump, although PCS overall was preferred. The 4. Discussion
nine 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 caring
Fig. 2 – Doses of propofol given by anaesthetist (ACS) for the wounds informed them if unpleasant or painful
compared with the doses requested by the patients (PCS) moments were to be expected, which gives them time to give
during the first PCS. the sedation and analgesia properly as described previously

5. 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.
[6]. As this was the first series of PCS in this unit, the procedure present sedation. PCS itself is a factor in the satisfaction
might be refined further as personnel get more acquainted among patients having cataract surgery, whether they did use
with the technique. We noticed that although special the pump with propofol or not [11] which in some way may
emphasis 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 together
with the sometimes impatient behaviour of the personnel 4.2. Safety
explain the intermittently high VAS scores recorded during
care of the wound and PCS. Astonishingly, despite the high Despite the fact that this study used propofol and alfentanil in
VAS 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 accomplished
therefore, further training may lead to less pain without the without extreme values in cardiopulmonary or BIS data. The
need 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 adverse
also 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 was
higher VAS scores) were not always accompanied by pressure also minor supports this further. One must, however, be
on the button to release the drug. There seemed to be cautious about the strength of this conclusion, as the number
cognitive 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 the
were unable to process that into the action of providing study is probably the explanation for there being fewer
themselves with more of the drug. No extra doses were given symptoms of sedation after the procedure, which also
by any bystander. explains the lack of effects on circulation and breathing.
The high scores for pain recorded, and which seem
unreasonably high, argues for more analgesic. This could 4.3. Sedation effects
theoretically be accomplished either by increasing the dose of
alfentanil given by PCS or by the supplementation of a longer- BIS monitoring was used to acquire objective data about the
acting analgesic at the start of the procedure. This must to be state of sedation, instead of using sedation scales, which often
examined further. We must point out that not a single patient involve some interactivity with the patient [7]. BIS indexes
reached 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 and
hidden 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 such
alfentanil, but that will only be achieved with less propofol, problems. BIS monitoring has been evaluated with propofol
which will result in reduced sedation (given that the Graseby sedation and is a good predictor of the level of sedation [13].
pump as presently sold commercially delivers only a fixed However, there is a lag time between decreasing values and
maximum volume). As far as we know patients appreciate the the outcome of an observer’s assessment [14]. As the purpose

6. 934 burns 34 (2008) 929–934
was not to delineate minor changes but rather to establish work. This study is performed on clinical basis of the Burn
sedation 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 our
results. As for PCS, few values were recorded below 80%,
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