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b u r n s 3 4 ( 2 0 0 8 ) 9 2 9 – 9 3 4
Patient 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
aDepartment of Anesthesiology and Intensive Care, Division of Perioperative Medicine, Linkoping University Hospital,
581 85 Linkoping, SwedenbThe Burn Unit, Department of Hand and Plastic Surgery, Linkoping University Hospital, 581 85 Linkoping, SwedencDepartment of Intensive Care, Linkoping University Hospital, 581 85 Linkoping, Swedend Faculty of Health Sciences, Department of Biomedicine and Surgery, Linkoping University Hospital, 581 85 Linkoping, Sweden
a r t i c l e i n f o
Article history:
Accepted 10 April 2008
Keywords:
Alfentanil
Anesthesia
Burns
Propofol
Patient controlled sedation
Sedation
a b s t r a c t
Background: Patient controlled sedation (PCS) enables patients to titrate doses of drugs by
themselves during different procedures involving pain or discomfort.
Methods: We studied it in a prospective crossover design using a fixed protocol without
lockout time to examine it as an alternative method of sedation for changing dressings in
burned patients. Eleven patients with >10% total burn surface area (TBSA) had their
dressings changed, starting with sedation by an anaesthetist (ACS). The second dressing
change was done with PCS (propofol/alfentanil) and the third time the patients had to
choose ACS or PCS. During the procedures, data on cardiopulmonary variables, sedation
(bispectral index), pain intensity (VAS), procedural details, doses of drugs, and patients’
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.
avai lab le at www.sc iencedi rec t .com
journal homepage: www.e lsev ier .com/ locate /burns
§ The study was performed at the Burn Unit, Department of Hand and Plastic Surgery, Linkoping University Hospital, OstergotlandCounty Council.
* Corresponding author. Tel.: +46 13 22 1834; fax: +46 13 22 2836.E-mail address: [email protected] (A. Nilsson).
0305-4179/$34.00 # 2008 Elsevier Ltd and ISBI. All rights reserved.doi:10.1016/j.burns.2008.04.002
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b u r n s 3 4 ( 2 0 0 8 ) 9 2 9 – 9 3 4930
1. Introduction
Patients with severe burns have severe pain and anxiety,
which have both psychological and physical effects for the
recovery process [1]. Pain for these patients is elicited not
only from the trauma event, but is also the result of
repeated procedures, dressing changes and physiotherapy.
These procedures are repeated, and often lead to appreci-
able pain, and they emphasise the need for advanced
strategies for the treatment of pain [2]. Morphine, fentanyl,
and alfentanil are commonly used opioids that provide
continuous, analgesia during and after the operation and
the intravenous route is often preferred for rapid pain
control. Self-titration of morphine (patient controlled
analgesia; PCA) has been suggested as an important
technique to meet the increasing and high requirement
for opioids [3]. Successful pain management requires that
pain is regularly assessed and its intensity evaluated as, for
example by a visual analogical scale (VAS), and adequate
pain relief must be provided accordingly [4]. Wound care
and dressing changes are associated not only with pain, but
with factors that are also known to affect the experience of
pain such as anxiety and loss of self-control. The ther-
apeutic challenge is to find methods that control pain and
relieve anxiety and at the same time avoid over-sedation
and a delayed recovery [1].
Patient controlled sedation (PCS) has received increasing
interest when it has been used to improve the conditions of
patients having painful or unpleasant procedures such as
lithotripsy, colonoscopy, or dental procedures [5–7]. It is
important also to others that the patient controlled sedation
technique has been used in these settings (lithotripsy,
dental, colonoscopy) without anesthesia-trained personnel.
Presently, in clinical practice at our hospital, lithotripsy is
done using a propofol-based PCS technique without
anesthesia-trained personnel. The procedure is based on
European Guidelines for sedation and/or analgesia by non-
anaesthesiology doctors [8]. In patients with burns we are
aware of only one dose-finding study that attempted to use
it as an alternative to traditional ways of giving analgesics
and sedatives [9].
The present study was designed to compare PCS, based on a
standard protocol, with routine sedation provided by anaes-
thetists, to assess the feasibility of PCS for adequate dressing
changes, and also to assess patients’ preferences. Close
surveillance of respiratory (respiratory rate/transcutaneously
assessed PCO2) and cardiovascular (heart rate/mean arterial
pressure) data were measured as an estimate of safety, as the
aim is to, in the future and after further refinement, to
implement this strategy in the care of patients with burns
without using specifically trained anaesthesia personnel.
2. Patients and methods
2.1. Study overview
After approval from the local ethics committee and informed
consent of the patients, 11 patients with ASA I or II scores with
burns exceeding 10% total burn surface area (TBSA) were
enrolled in a prospective exploratory study at the National
Burn Centre at Linkoping University Hospital, Linkoping,
Sweden.
Inclusion criteria were: need for analgesia and sedation for
at least two consecutive dressing changes. Patients with
injures of more than 10% or more than 5% full thickness was
asked to participate. Exclusion criteria were ASA III–V, burned
hands (because of difficulties in using the PCS device) or
difficulties in communication or understanding of the proce-
dure. Four patients entered the study but did not fulfil the
protocol because only one or two dressing changes were
needed that required analgesia and sedation.
The study was designed as a single-centre, single-case,
crossover, controlled study. Patients were their own control
group, because they started with dressing changes under
sedation by an anaesthetist (ACS, FS or ZB; anesthesiologists
with 10 years experience of burn care) using routine sedating
techniques. While the patient breathed oxygen and air,
sedation and analgesia were accomplished with intermittent,
intravenous propofol (Propofol-1Lipuro 10 mg/ml, Braun) and
fentanyl (Fentanyl1 0.05 mg/ml, Braun). The second dressing
change was done using PCS as described below. At the third
dressing change the patients were asked to choose one of the
two techniques.
During the sedation procedures a protocol was used to
collect cardiopulmonary data (heart rate, non-invasive blood
pressure, saturation, and respiratory rate). Transcutaneous
PCO2 were collected using TCM3—TINA (Radiometer, Copen-
hagen, Denmark). Intensity of pain was assessed using a 11-
point visual analogue scale (VAS) when patients were able to
answer during the procedure, after finishing the dressing
changes, and 10 min later. Complications were recorded,
whether it was possible to treat the wounds adequately (yes
or no), and the duration of treatment. The bispectral (BIS)
index was monitored using the A-2000 BISTM system (Aspect
Medical Systems, Natick, MA, USA). The recording of all these
variables started before the onset of sedation and every 3 min
during the procedure, and up to 30 min afterwards. If a lower
BIS index appeared on the display between measurement
points, the lowest observed index was recorded. Within 2 h of
completion of the dressing change, each patient was asked
about how they experienced the sedation and the awakening
from it.
2.2. Patient controlled sedation
One hour before the dressing change all patients were given
their regular daytime analgesics. These comprised: acetami-
nophen (Panodil1 1 g, GlaxoSmithKline Healthcare) and a
long-acting opioid, Oxycodone (Oxycontin1 between 5 and
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
painful events were predicted during the procedure and
conveyed to the patients so that they could prepare them-
selves by giving analgesia and sedation.
Propofol, 20 mg/ml (Propofol-1Lipuro 20 mg/ml, Braun,
Sweden) and alfentanil 0.5 mg/ml (Rapifen1 0.05 mg/ml,
Janssen-Cilag, Sweden) were mixed to 14.8 mg/ml of propofol
and 0.13 mg/ml of alfentanil in the final solution. A bag
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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.
b u r n s 3 4 ( 2 0 0 8 ) 9 2 9 – 9 3 4 931
containing the mixture was connected to an electromecha-
nical pump (Graseby 9300 PCS, Graseby Medical Ltd., Watford,
UK). Each time the button was pushed, the patient received
0.3 ml of the mixture, equivalent to 4.44 mg propofol and
0.039 mg alfentanil. No lockout period was used, which
resulted in a quantity of 22.2 mg propofol and 0.20 mg
alfentanil possible to give in 1 min.
For comparison and calculations the analgesic doses that of
alfentanil was multiplied by a factor of 7, resulting in
equipotent doses of morphine. Doses of fentanyl were multi-
plied by the factor of 100 [10].
2.3. Data analysis and statistics
Data are presented as either mean (S.D.) or median (inter-
quartile range). For the statistical analysis we used Statis-
tica1 Version 6.1 (Stat Soft, Inc., Tulsa, USA). To assess
differences between groups we used the Wilcoxon Matched
Pairs Test. Changes over time in surveillance data between
ACS and all PCS procedures were evaluated by repeated
measures ANOVA. Values of P < 0.05 were accepted as
significant.
Table 2 – Cardiopulmonary data and sedation data during AC
ACS
Mean (S.D.) Min–Max Me
SpO2, % 98 (3) 84–100 99
RR 14 (2) 8–17 16
PtcCO2 (kPa) 5.3 (0.4) 4.5–6.2 5
BIS index 84 (11) 48–99 93
HR 80 (11) 56–118 80
MAP (mmHg) 70 (15) 33–110 83
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
3. Results
3.1. Details of patients (Table 1)
All the patients started the study with ACS followed by at least
two PCS. Ten of the 11 patients preferred to continue dressing
changes using PCS after the first ACS and PCS. One patient was
indifferent to the techniques but finally chose PCS.
3.2. Cardiopulmonary and surveillance data(Fig. 1 and Table 2)
Differences were found for SpO2, BIS, and transcutaneous
PCO2, between ACS and PCS. PCS gave higher mean SpO2
concentrations, but lower PCO2, and less sedation according to
BIS monitoring.
During ACS there was a slight decrease in saturation (<90%)
in two cases, the lowest respiratory rate was 8, and a lowest
BIS index was 48. Blood pressure (MAP) was reduced during
both techniques, the lowest values being between 50 and 68%
of baseline. Equivalent data during PCS showed no saturation
value lower than 94% and no respiratory rate less than 10. The
S and PCS
PCS Statistical differences (P)
an (S.D.) Min–Max
(2) 94–100 0.032
(5) 10–30 0.707
.2 (0.5) 4.0–6.2 0.004
(5) 67–99 0.027
(11) 65–102 0.686
(11) 58–115 0.663
.
= bispectral index, HR = heart rate and MAP = mean arterial pressure.
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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).
b u r n s 3 4 ( 2 0 0 8 ) 9 2 9 – 9 3 4932
lowest MAP recordings were within 60 and 96% of baseline.
Reduction in the BIS index also occurred during PCS with six
recordings less than 80.
3.3. Amount of drug given (Table 1 and Fig. 2)
During PCS all patient requested lower doses of propofol and
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
18.6 (9.0) mg). There was no difference in duration of
procedure between PCS (67.5 (19.0) min) and ACS (69.3
(26.7) min).
During PCS procedures, four patients had a third or less of
the required doses. The remaining seven patients had more
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
nine remaining patients were satisfied with how they were
Fig. 2 – Doses of propofol given by anaesthetist (ACS)
compared with the doses requested by the patients (PCS)
during the first PCS.
given the doses. The capacity of the pump in relation to the
patients with high dose demands is shown in Fig. 3.
3.4. Procedure rating by personnel
After dressing changes, wound care personnel said that in all
cases, during ACS and PCS, sedation was adequate and, wound
care conditions was good. Two surgeons indicated, however,
that cleansing of the wounds could have been better on two
occasions during PCS.
3.5. Pain ratings (Table 3)
The highest mean (S.D.) pain ratings recorded, during wound
treatment were greater for PCS (4.9 (2.4)) than for ACS (1.5
(1,0)). Immediately and 10 min after dressing changes there
were no differences.
4. Discussion
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
for the wounds informed them if unpleasant or painful
moments were to be expected, which gives them time to give
the sedation and analgesia properly as described previously
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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.
b u r n s 3 4 ( 2 0 0 8 ) 9 2 9 – 9 3 4 933
[6]. As this was the first series of PCS in this unit, the procedure
might be refined further as personnel get more acquainted
with the technique. We noticed that although special
emphasis was placed on preparing the patients and predicting
painful events, this was at times missed and may together
with the sometimes impatient behaviour of the personnel
explain the intermittently high VAS scores recorded during
care of the wound and PCS. Astonishingly, despite the high
VAS reported, it did not seem to affect the patients overall
judgement of the technique. To optimise the procedure,
therefore, further training may lead to less pain without the
need to change the doses of any drugs. The finding that the
length of the procedures done by ACS and PCS did not differ
also suggests that PCS was adequate.
We made an interesting, new discovery during this trial. In
all patients verbal complaints of pain (with corresponding
higher VAS scores) were not always accompanied by pressure
on the button to release the drug. There seemed to be
cognitive dysfunction with the present drugs and protocol
where, despite patients verbally complaining of pain, they
were unable to process that into the action of providing
themselves with more of the drug. No extra doses were given
by any bystander.
The high scores for pain recorded, and which seem
unreasonably high, argues for more analgesic. This could
theoretically be accomplished either by increasing the dose of
alfentanil given by PCS or by the supplementation of a longer-
acting analgesic at the start of the procedure. This must to be
examined further. We must point out that not a single patient
reached the maximum capacity of the pump; however, at the
same time it is difficult to give the maximum dose as there is a
hidden lockout time during which the pump delivers a dose
already requested. An alternative is to increase the volume of
alfentanil, but that will only be achieved with less propofol,
which will result in reduced sedation (given that the Graseby
pump as presently sold commercially delivers only a fixed
maximum volume). As far as we know patients appreciate the
present sedation. PCS itself is a factor in the satisfaction
among patients having cataract surgery, whether they did use
the pump with propofol or not [11] which in some way may
contribute to acceptance of the pain recorded in our study.
4.2. Safety
Despite the fact that this study used propofol and alfentanil in
concentrations higher than evaluated previously [6,7,11,12]
and a device without a lock out time, PCS was accomplished
without extreme values in cardiopulmonary or BIS data. The
patients were monitored closely and were given supplemen-
tary oxygen and it is therefore unlikely that any adverse
reaction has been overlooked. In all, we recorded no single
value that indicated compromise of breathing or circulation.
The fact that the corresponding decrease in the BIS index was
also minor supports this further. One must, however, be
cautious about the strength of this conclusion, as the number
of patients was small.
The smaller amounts of analgesic and sedative used in the
study is probably the explanation for there being fewer
symptoms of sedation after the procedure, which also
explains the lack of effects on circulation and breathing.
4.3. Sedation effects
BIS monitoring was used to acquire objective data about the
state of sedation, instead of using sedation scales, which often
involve some interactivity with the patient [7]. BIS indexes
were collected during the procedure with no major distur-
bances. The position of the patient’s head must be still and
controlled as the BIS monitor detects muscular movement,
and the signal quality may then be affected. We had few such
problems. BIS monitoring has been evaluated with propofol
sedation and is a good predictor of the level of sedation [13].
However, there is a lag time between decreasing values and
the outcome of an observer’s assessment [14]. As the purpose
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b u r n s 3 4 ( 2 0 0 8 ) 9 2 9 – 9 3 4934
was not to delineate minor changes but rather to establish
sedation levels, mainly for the group using PCS, we do not
think that this has an impact on the interpretation of our
results. As for PCS, few values were recorded below 80%,
which is similar to the findings made by Coimbra et al. [9]. The
lowest values were present during ACS, which has been a
common finding by other authors who compared ASC and PCS
such as in, colonoscopy [6]. In that study the corresponding
figures were 58 (ACS) and 71 (ACS), respectively.
4.4. Other issues
There are some other issues of importance that should be
discussed.
Firstly, when we compare PCS and ACS we must
emphasise that the present standard in Sweden is to use
ACS for patients with major burns. We know that inter-
nationally many units do their dressings with no anaesthetist
support. We think that this argues for PCS as an interesting
alternative to the present procedure, in which anaesthetic
personnel are required, and it also may explain why patients
accept the procedure to such a large extent with not much
sedation. The PCS technique would certainly reduce con-
sumption of resource.
For PCS in the present study we used a push-button device,
which made it difficult to recruit patients with burnt hands.
These are common among our patients [15]. Several candi-
dates for the investigation were also excluded for this reason.
There are, however, other techniques that could be tried for
these patients.
The study was not blind; unfortunately this is not possible
with these techniques. We claimed that we used ‘‘true PCS’’, as
no ‘‘lockout’’ time was used. This is not completely true as in
practice there is a lockout time when the pump is giving the
actual dose. This time is in the range of 15 s, and may explain
the discrepancy between the doses requested and the doses
delivered.
In conclusion, PCS as presented in this study using a fixed
protocol appears an interesting alternative to ACS for dressing
changes in serious burns. The patients chose PCS, and
preferred it because they had better control and less sedation
after the procedure despite having less sedation during it and
more pain.
Conflict of interest
None of the authors have any financial or personal relation-
ship with people or organizations that could influence this
work. This study is performed on clinical basis of the Burn
Unit, with no external influence.
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