comment on matsota et al

Correspondence

Baclofen pumps: commenton Anderson et al.

SIRIR—We read with interest the report of Anderson et al. (1)

concerning the use of baclofen pumps and reversible coma

in children. We would like to report three children who

experienced similar reversible coma following placement

of baclofen pumps under general anaesthesia. All three

were alert and responding when discharged from the

PACU to the ward. However, 1.5 h later, we were asked to

reevaluate the patients because of coma, hypotension, and

bradycardia. Since the patients had received morphine in

the PACU, a trial of Narcan was used with no improve-

ment. All patients were given oxygen, fluid boluses and

atropine. The baclofen infusion was stopped, and we

continued to monitor our patients with other interven-

tions. All of our patients responded slowly to our

therapeutic measures and made an uneventful recovery.

We thank Anderson et al. for their report and excellent

discussion of the issues relating to starting the baclofen

infusion in the immediate postoperative period and the

concerns and confusion in treatment decisions.

Timothy W. Martin

James F. Mayhew

Arkansas Children’s HospitalLittle Rock, AR, USA

Reference1 Anderson MJ, Farmer JS, Brown K. Reversible coma in children

after improper baclofen pump insertion. Paediatr Anaesth 2002;12: 454–460.

Baclofen pumps: commenton Anderson et al.

SIRIR—We read with interest the report of Dr Anderson and

colleagues who experienced unexpected coma in five

patients postoperatively (1). Although some influence of

the anaesthetic technique and analgesic medication could

be related to this occurrence, the delay strongly suggests a

relation with an accidental high dose of baclofen. Based on

our early experiences of overdosing (2), we focused mainly

on the intrathecal baclofen procedures. In hundreds of

implantations involving adults and children, we have used

another procedure for purging the pump, without any

problem of postoperative coma or even sedation. In our

procedure, the pump function testing in vitro is not carried

out with sterile water but with baclofen solution. This

includes emptying the pump reservoir followed by filling

it with baclofen solution, usually 2000 lgÆml)1, before

starting purging. By using a sterile video camera drape for

covering the Medtronic programming head, the pump can

be programmed for purging during the operation.

After surgery, the implanted catheter dead space is

calculated as mentioned in the article. The pump is then

programmed for a bolus of 75% of the catheter dead space

and in addition for the desired continuous daily infusion

dose (2 · the effective test bolus dose during the screening

phase). The 75% filling is an additional safety procedure,

preventing overdose in cases of error in measurement of

catheter length or calculation. The consequence is that

postoperatively, the patient will not immediately have

intrathecal medication, but will gradually receive the

therapeutic continuous baclofen infusion. In this way the

anaesthetic and analgesic influences are negligible. An

additional advantage is that 0.3–0.4 ml water, which

would influence the cerebrospinal fluid (CSF)-pH, is not

injected into the intrathecal space. The need for immediate

purging of the complete tubing ‘allowing the neurosur-

geon to titrate the rate of the infusion prior to discharge

from the hospital’ is not clear to us.

E . Delhaas

S . Goslinga

Department of Anaesthesiology and Pain TreatmentGroene Hilledijk, Rotterdam, the Netherlands

(Email: [email protected])

References

1 Anderson KJ, Farmer JP, Brown K. Reversible coma in childrenafter improper baclofen pump insertion. Paediatr Anaesth 2002;12: 454–460.

2 Delhaas EM, Brouwers JRBJ. Intrathecal overdose: report of 7events in 5 patients and review of the literature. Int J ClinPharmacol Ther Toxicol 1991; 29: 274–280.

Authors’ reply

SIRIR—We thank the authors for their letter concerning our

article (1). We agree with them, and this was the message of

our analysis that the coma in these children was more likely

due to inadequate latency between the pump purge and

the implantation. We addressed the problem by allowing

the sterile water purge to fully take place prior to filling the

baclofen reservoir. We have alerted the company supply-

ing the pumps to that effect and a warning has been sent to

Paediatric Anaesthesia 2003 13: 640–648

640 � 2003 Blackwell Publishing Ltd

all the centres implanting pumps. The cost of these pumps

at malfunction is elevated and we have preferred not to

alter the company’s protocol to ensure the pump malfunc-

tion rate is kept to a minimum.

With respect to the bolus, we have preferred to use

more dilute concentration initially and calculate the bolus

at 100% instead of 75%. I think the author’s suggestion

of using 75% of this amount is an interesting one for

safety issues, especially if a 2000 lgÆml)1 concentration is

used. Our analysis suggested inadequate latency between

the sterile water purge and baclofen bolus was the

problem rather than the bolus. Patients are kept in the

postanaesthesia care unit for 6 h and despite our calcu-

lation of the bolus at 100%, no respiratory depression or

comatose state has recurred following the change in our

latency policy. These spastic children more likely benefit

from having baclofen, which starts its effect usually

within 30 min following cessation of intraoperative con-

ditions, because the postoperative pain exacerbates their

spasticity. In young children requiring low doses, a

shortfall of 25% in the bolus dose could mean that the

baclofen effect would only start 24–48 h after implana-

tion.

K.J . Anderson

J . -P . Farmer

K. Brown

Department of Anaesthesia, Montreal Children’s HospitalMontreal, Quebec, Canada


Reference

1 Anderson KJ, Farmer JP, Brown K. Reversible coma in childrenafter improper baclofen pump insertion. Paediatr Anaesth 2002;12: 454–460.

Postanaesthetic excitation and agitation

SIRIR—I read the Editorial on postanaesthetic excitation (1)

with a little bit of agitation. The author suggested that

excitation was not reported at the time of the initial

introduction of sevoflurane in Japan. Although not too

much emphasized, excitation or agitation at emergence

was described not only in the Japanese literature (2–4) but

also in a European journal in 1991 (5) and this journal in

1993 (6).

In 1991, Naito et al. (5) reported a greater incidence of

postoperative restlessness and agitation after sevoflurane

(60%) than after halothane (20%). and in 1993, Muto et al.(6) reported a greater incidence of excitement and agitation

in the recovery room in comparison with halothane

anaesthesia.

It remains unclear why our Swiss colleague did not cite

these last two articles from the journals of the Western

world. It may be that in 1993 Paediatric Anaesthesia was not

yet indexed in Index Medicus or MEDLINE.

Masao Yamashita

Ibaraki Children’s Hospital MitoIbaraki Japan

References

1 Johr M. Postanaesthesia excitation. (Editorial). Paediatr Anaesth2002; 12: 293–295.

2 Iwai S, Hoshina H, Murata H et al. Clinical experiences ofsevoflurane in pediatric anesthesia. (in Japanese). Masui 1987;36: 1796–1801.

3 Furuya Y, Tachibana C, Kobayashi N et al. Comparison ofsevoflurane and halothane in pediatric anesthesia. (in Japan-ese). Masui 1993; 42: 46–51.

4 Yamamoto I, Yukioka H, Fujimori M. Clinical study ofpostoperative sedation in pediatric patients- Effects of inhala-tion anesthetics and postoperative analgesics. (in Japanese).Masui 1994; 43: 1191–1195.

5 Naito Y, Tamai S, Shingu K et al. Comparison betweensevoflurane and halothane for paediatric ambulatory anaesthe-sia. Br J Anaesth 1991; 67: 387–389.

6 Muto R, Miyasaka K, Takata M et al. Initial experience ofcomplete switchover to sevoflurane in 1550 children. PaediatrAnaesth 1993; 3: 229–233.

Comment on editorial by M Johr

SIRIR—I was rather astonished to read the editorial by

Dr Johr on postanaesthesia excitation, in particular,

regarding the description of sevoflurane. I felt obligated

to respond to his dubious assumptions such as ‘It remains

unclear why our Japanese colleagues did not report this

striking phenomenon’ and ‘It may be their cultural

background accepted crying after surgery, probably asso-

ciated with insufficient pain relief in the early 1990s, to be

normal behaviour for children.’ (1)., Sevoflurane was

approved in Japan in January or 1990, rather than 1992,

as Dr Johr stated, and has been the principal inhalation

agent of all ages in Japan since then, Sevoflurane has been

the sole inhalation agent in our institution from July 1990

to today. We reported our initial experience in Paediatric

Anaesthesia in 1993 (2). In this paper, we discussed

agitation during emergence from sevoflurane anaesthesia,

as we experienced occasional agitation during our initial

period of experience with the agent. We were not used to

such a rapid recovery from sevoflurane then, but it became

obvious that common sense in paediatric anaesthesia

could easily overcome the situation., We soon found and

reported that appropriate adjustment of the anaesthesia

level at the end of surgery (not lightening anaesthesia

� 2003 Blackwell Publishing Ltd, Paediatric Anaesthesia, 13, 640–648

CORRESPONDENCE 641

prematurely), minimum stimulation during transfer to

and time in the recovery room, and anticipatory admin-

istration of analgesics (regional anaesthesia and ⁄ or nar-

cotics) substantially decreased such episodes of excitation

(2). We felt then that sevoflurane and halothane produced

a similar incidence of postanaesthetic excitement, as

reported by others later (3)., We have been following the

above policy on sevoflurane administration for the past

12 years and we have not found anything particularly

disturbing about postanaesthesia excitement. This is not to

say that we do not care about crying children. We were

providing active care management as early as the 1980s in

Japan (4). We are not saying that sevoflurane is a perfect

agent, rather that it is similar to other inhalation agents

and demands sensitivity to the patient.

Katsuyuki Miyasaka

Director, Department of Anaesthesia and ICU NationalChildren’s Medical Center

Nation Center for Child Health and DevelopmentTokyo, Japan

References

1 Johr M. Postanaesthesia excitation. (Editorial). Paediatr Anaesth2002; 12: 293–295.


3 Murray DJ, Cole JW, Shrock CD et al. Sevoflurane versushalothane: effect of oxycodone premedication on emergencebehaviour in children. Paediatr Anaesth 2002; 12: 308–312.

4 Shandling B, Steward DJ. Regional analgesia for postoperativepain in paediatric outpatient surgery. J Pediatr Surg 1980; 15:477–480.

Authors’ reply

SIRIR—Thank you for the opportunity to reply to

Dr Yamashita and Dr Miyasaka I appreciate that the huge

Japanese experience with sevoflurane receives more atten-

tion than it did in my editorial (1) and that additional

references are cited. I apologise if this editorial appeared

not to sufficiently honour the Japanese experience. This

editorial was based on five years’ experience after a

complete switch from halothane to sevoflurane in the

authors’ own institution – sevoflurane has undoubtedly

led to increased safety – and on a complete MEDLINE

search; most of the relevant literature is included.

It is undoubtedly correct that restlessness and agitation

were reported before the randomized, controlled trial of

Aono et al. (2), however, this was not greatly emphasized.

As early as 1991, Naito et al. (3) reported agitation in 9 ⁄ 15

children with sevoflurane compared with 3 ⁄ 15 after

halothane. This difference did not reach statistical signi-

ficance and was attributed to pain and apparently treated

effectively with indomethacin in all patients. This striking

effectiveness of nonsteroidals probably does not reflect the

experience of the majority of paediatric anaesthesiologists

today, at least in Europe. In 1993 Muto, Miyasaka et al. (4)

reported in this journal, not yet indexed in MEDLINE, that

special care needs to be taken during emergence from

sevoflurane anaesthesia because children occasionally

became agitated in the recovery room. Fortunately, com-

mon sense in paediatric anaesthesia could easily overcome

the situation: the authors reported that minimal stimula-

tion during transfer to the recovery room and emergence

from anaesthesia might be beneficial, in addition to

anticipatory administration of analgesics. This editorial

(1) concentrated on the convincing evidence that agitation

unrelated to pain occurs after sevoflurane- or desflurane-

based anaesthetics. Therefore, strategies for active preven-

tion and treatment must be familiar to every anaesthetist

using these newer agents. Opioids and clonidine have

been reported in the literature to be effective. Small doses

of thiopentone or propofol are used in our institution, as

unstimulated recovery has not been proven to be reliably

successful. This discussion on agitation in children after

sevoflurane- or desflurane-based anaesthetics shows that it

may take several years until even very common side-

effects are clearly recognized by the anaesthetic commu-

nity: it took nearly eight years from the release of

sevoflurane in Japan in January 1990 to the publication

of the first paper focusing on agitation in pain-free

children (December 1997) (2). This delay of years or even

decades until recognition is not unusual for drug-related

phenomena, e.g. etomidate and cortisol biosynthesis,

propofol and its infusion syndrome, or – in view of the

severity, more comparable – spinal lidocaine and transient

neurological symptoms. The importance of close collabor-

ation and continuous exchange of information among

paediatric anaesthetists worldwide has to be emphasized

in order to minimize this delay. Therefore, I would like to

thank Dr Yamashita and Dr Miyasaka for their contribu-

tions.

Martin Johr

Department of AnaesthesiaKantonsspital

Luzern, Switzerland

References

1 Johr M. Postanaesthesia excitation. Paediatr Anaesth 2002; 12:

293–295.2 Aono J, Ueda W, Mamiya K et al. Greater incidence of delirium

during recovery from sevoflurane anesthesia in preschool boys.Anesthesiology 1997; 87: 1298–1300.

3 Naito Y, Tamai S, Shingu K et al. Comparison betweensevoflurane and halothane for paediatric ambulatory anaesthe-sia. Br J Anaesth 1991; 67: 387–389.


642 CORRESPONDENCE


Comment on Matsota et al.

SIRIR—As an anaesthetist with practice in the areas of adult

neuroendocrine surgery and paediatric oncological sur-

gery I was interested to read the description of anaesthesia

for phaeochromocytoma surgery (1) in a 5-year old. The

authors described a spectacular increase in haemodynamic

parameters during tumour manipulation which would

lead me to believe that the pre- and intraoperative

catecholamine blockade was inadequate. I feel that the

criteria for adequate alpha blockade should include nasal

stuffiness as well as the more obvious postural hypoten-

sion. Intraoperative haemodynamic control can be much

smoother if intravenous magnesium sulphate is employed.

This may be given as an initial bolus of 50 mgÆkg)1 over

10 min before induction of anaesthesia followed by a

continuous infusion of 15 mgÆkg)1Æh)1 plus bolus doses of

15 mgÆkg)1 if required. A serum level of 2–4 mmolÆl)1

should be aimed for if monitoring is available. Care must

be taken with nondepolarizing muscle relaxants which

should be used in lower doses with peripheral nerve

stimulator monitoring. I routinely use an intraoperative

low thoracic epidural for open phaeochromocytoma sur-

gery but not for laparoscopic resections. It should not

produce a fall in blood pressure due to afterload reduction

if full alpha blockade and fluid replacement have been

successful preoperatively. I would be interested to know if

other anaesthetists would consider using magnesium in

this context.

Patrick Butler

Shackleton Department of AnaestheticsSouthampton General Hospital

Tremona Road SouthamptonUK


Reference

1 Matsota P, Avgerinopoulo-Vlahou A, Velegrakis D. Anaesthe-sia for phaeochromocytoma removal in a 5-year-old boy.Paediatr Anaesth 2002; 12: 176–180.

Authors’ reply

SIRIR—We would like to thank you for your valuable

remarks, although we have already pointed out the lack

of our experience, as this case was the first one in our

hospital for the past 20 years. Our perioperative manage-

ment was according to the bibliography and the medical

publications until 1999, and our criteria, for the perioper-

ative adrenergic blockade’s efficacy was based on the

posture hypotension and on the Hct fall. We agree that the

adrenergic blockade was not appropriate and that there-

fore the child was unstable intraoperatively. Concerning

the role of Mg++ in phaeochromocytoma management, we

have no personal experience. We are aware of the

hypomagnesaemia that occurs in patients with elevated

blood catecholamines. As far as we know, there are only

experimental data regarding magnesium administration in

children and there is a lack of clinical reports about this

matter. In case we have to handle another childhood

phaeochromocytoma in the future we will consider your

remarks.

P. Matsota*

A. Avgerinopoulou-Vlachou

D. Velegrakis

Department of AnaesthesiologyChildren’s Hospital

‘P & A Kyriakou’ AthensGreece

*(Email: [email protected])

A double bloody tap on epidural insertion

SIRIR—A complication that occurred on attempted insertion

of epidural is reported. In this instance, the patient’s

underlying pathology possibly predisposed him to this

complication.

An 18-month-old, boy (weight 6 kg) was anaesthet-

ized for a fundoplication. He was born preterm at

29 weeks gestation with severe intrauterine growth

retardation and required ventilation for the first

4 months of life. The patient suffered from chronic

neonatal lung disease, was oxygen dependent and had

documented significant pulmonary hypertension with

right ventricular fibrosis.

Following induction of anaesthesia, epidural insertion

was attempted at the L2 ⁄L3 interspace. An 18G paediatric

Tuohy needle (Portex�, Hythe, UK) was inserted using the

loss of resistance to saline technique. On entering the

epidural space, blood appeared at the hub of the needle.

The needle was withdrawn and reinserted at the L1 ⁄L2

interspace. Entering the epidural space was uneventful.

However, after insertion of the 21G epidural catheter,

blood was aspirated through the catheter. The procedure

was abandoned.

Inadvertent cannulation of an epidural blood vessel is a

recognized complication of this procedure however, its


CORRESPONDENCE 643

occurrence in paediatric practice is uncommon. In his

series of 650 paediatric epidurals, Dalens reported an

incidence of blood reflux of 0.9% (1).

It could be postulated that in this patient, the high

pulmonary artery pressures were directly transmitted to

the thin-walled valveless epidural veins causing them to

be engorged thus directly contributing to this complica-

tion.

It is recommended that anaesthetists be aware of the

potential for this complication in this specific group of

patients.

Mark Sacks

Department of AnaesthesiaSt Mary’s Hospital, Praed Street London, W2 1NY UK


Reference

1 Dalens B, Chrysostome Y. Intervertebral epidural anaesthesia inpaediatric surgery: success rate and adverse effects in 650consecutive procedures. Paediatr Anaesth 1991; 1: 107–117.

Response to editorial by Davidson

SIRIR—We were very interested in Dr Davidson’s recent

editorial arguing for an urgent redress of the lack of

knowledge available on the incidence and psychological

impact of awareness during paediatric anaesthesia (1). We

would like to make colleagues aware of our ongoing work

on this important topic.

With the help of a substantial grant from the Wellcome

Foundation, we recently commenced a large-scale study of

approximately 600 hundred children to determine the

incidence of awareness in paediatric anaesthesia using the

isolated-forearm technique (2,3). We consider the isolated-

forearm technique to be the ‘gold standard’ by which to

detect awareness (4). Unlike the measures derived from

the auditory evoked response and bispectral index, this

technique does not require calibration for use with

children.

As noted by Dr Davidson, there are differences in

memory formation in children and adults. Explicit

memory, which refers to conscious recollection, is

generally better in adults. However, implicit memory,

which influences behaviour in the absence of conscious

recollection, is usually as good in children as in adults

(5). Implicit memory for information presented during

anaesthesia has been demonstrated in adults (6). Thus

children are as likely to have implicit memory for the

intraoperative period as adults. In addition to using the

isolated-forearm technique to assess intraoperative

awareness, our study tests whether implicit memory

may result from awareness or unconscious processing.

The psychological impact of awareness and implicit

memory will be examined using a postoperative beha-

vioural questionnaire (7).

We look forward to presenting the results of our study

in the not too distant future.

Dr Ian Barker*

Dr Catherine Deeprose†

Dr Jackie Andrade‡

*Consultant Anaesthetist, Sheffield Children’s Hospital†Research Associate, Department of Psychology

University of Sheffield (Correspondence)‡Senior Lecturer, Department of Psychology

University of Sheffield, Sheffield, UK

References

1 Davidson AJ. Awareness and paediatric anaesthesia. PaediatrAnaesth 2002; 12: 567–568.

2 Russell IF, Wang M. Absence of memory for intra-operativeinformation during surgery with total intravenous anaesthesia.Br J Anaesth 1999; 86: 196–202.

3 Byers GF, Muir JG. Detecting wakefulness in anaesthetisedchildren. Can J Anaesth 1997; 44: 486–488.

4 Jones JG, Aggarwal SK. Monitoring Depth of Anesthesia. In:Ghoneim, MM, eds. Awareness during anesthesia. Oxford: But-terworth-Heinmann, 2001: 69–92.

5 Naito M, Komatsu S. Processes involved in childhood devel-opment of implicit memory. In: Graf, P, Masson, MEJ, eds.Implicit memory. New Directions in Cognition, Development andNeuropsychology. Erlbaum: Hillsdale, NJ, 1993: 231–260.

6 Merikle PM, Daneman M. Memory for unconsciously perceivedevents: Evidence from anesthetized patients. Conscious Cog1996; 5: 525–541.

7 Kotiniemi LH, Ryhanen PT, Moilanen IK. Behavioural changesin children following day-case surgery. a 4-week follow-up of551 children. Anaesthesia 1997; 52: 970–976.

Comment on Cohen et al.

SIRIR—The increasing coverage of emergence agitation in the

paediatric anaesthetic literature is to be welcomed. We

feel, however, that we must disagree with the assertion by

Cohen et al. (1) that ‘these agents (midazolam and prop-

ofol) are not recommended for reducing emergence

agitation in children…’.

A consideration of the pharmacokinetics of intravenous

anaesthetics would suggest that any clinically useful result

could not have been achieved given the construction of

their study. We would suggest that the effect site concen-

trations of midazolam and propofol in the doses described

would have been insufficient to demonstrate a response,

given that their time of administration was immediately

after induction.


644 CORRESPONDENCE

It is our personal experience that small doses of

propofol, as low as 0.5 mg kg)1 given intravenously

immediately prior the removal of a laryngeal mask or

tracheal tube, effectively reduces the incidence of emer-

gence agitation following sevoflurane anaesthesia.

Following positive feedback from our recovery staff, we

are currently awaiting ethics committee approval for a

study which we hope will provide scientific evidence that

appropriately timed administration of propofol may have

an important role in the prevention of this distressing

phenomenon.

P.C. Stewart F F A R C S IF F A R C S I *

P. Cunnington F R C AF R C A †

R. Martin F R C AF R C A †

Consultant paediatric anaesthetists*Department of Anaesthesia

The New Children’s Hospital SydneyNew South Wales

†Department of Anaesthesia, Princess Margaret’sHospital for Children, Perth

Western Australia, Australia

Reference

1 Cohen IT, Drewsen S, Hannallah RS. Propofol or midazolam donot reduce the incidence of emergence agitation associated withdesflurane anaesthesia in children undergoing adenotonsillec-tomy. Paediatr Anaesth 2002; 12: 604–609.

Authors’ reply

SIRIR—We appreciate Dr Stewart and his associates’ com-

ments concerning our paper (1). We agree that hypnotics

and sedatives given during the immediate pre- and

postemergence period can reduce the incidence of agita-

tion associated with desflurane and sevoflurane. Unfortu-

nately, as described by Welborn et al. (2), recovery in these

cases is prolonged. The aim of our study was to reduce the

incidence of emergence agitation while preserving rapid

recovery and extubation. In our discussion we commented

that although the timing and doses of propofol and

midazolam may not have been sufficient to reduce

agitation, they did delay awaking and time to discharge.

This is why we state that, with our technique, these

medications are not recommended. We look forward to the

results of Dr Stewart et al.’s proposed study.

Ira Todd Cohen , M DM D

Associate Professor of Anaesthesiology and TediatricsThe George Washington University Medical Center

Staff AnaesthesiologistChildren’s National Medical Center

References

1 Cohen IT, Drewsen S, Hannallah RS. Propofol or midazolam donot reduce the incidence of emergence agitation associated withdesflurane anaesthesia in children undergoing adenotonsillec-tomy. Paediatr Anaesth 2002; 12: 604–609.

2 Welborn LG, Hannallah RS, Norden JM et al. Comparison ofemergence and recovery characteristics of sevoflurane, desflu-rane, and halothane in pediatric ambulatory patients. AnesthAnalg 1996; 83: 917–920.

Response to editorial by G. Chalkiadis

SIRIR—I read with interest and chagrin the editorial ‘The rise

and fall of continuous epidural infusions in children’ by

George Chalkiadis (1). He states that epidural analgesia in

children is unreliable, labour intensive, inadequate for

pain relief, risky to children and costly. He has ‘thrown

down the gauntlet’ to his colleagues to demonstrate

improved clinical outcomes and the cost benefits of this

analgesic method.

It seems Dr Chalkiadis is unaware of the more recent

literature in this area that has seen the development of a

new approach to epidural placement in children, and to

the attempts to quantify clinical outcomes. I am referring

to the placement of epidural catheters via the caudal

space in the thoracic or lumbar area with the aid of

electrical stimulation (2). Dr Chalkiadis correctly refers to

epidural analgesia being reliant upon optimal position-

ing of the catheter tip within the epidural space. With

our colleague’s (Dr B.C.H. Tsui) innovation, we

improved our epidural success rate from 68% to 86%

in the first year of its use with gradually increasing

success in 2002 of 91% (unpublished data collected from

prospective pain service database). Improved epidural

catheter positioning improves analgesia and the use of

the caudal insertion site reduces the risks of needle

trauma quoted. Dr Chalkiadis does note that side-effects

are no more common with epidurals than with intra-

venous opioids, however, with optimal catheter posi-

tioning opioids can be used in smaller amounts or not at

all further reducing side-effects. In prospectively collec-

ted data on 289 patients receiving caudal placement of a

lumbar or thoracic catheter the incidence of nausea ⁄ vom-

iting, pruritus and respiratory depression are all less in

our patients with epidurals than those with patient

controlled analgesia (3).

Dr Chalkiadis concedes there are patient subgroups

for which the risk ⁄ benefit ratio is acceptable for epidur-

als but that improved clinical outcomes and cost benefits

have not been shown. Several authors have examined

the patient outcomes of epidural analgesia in such


CORRESPONDENCE 645

groups. Two retrospective studies of patients undergoing

Nissen fundoplications compared postoperative pain

management with epidural analgesia to intravenous

opioids. One study showed comparable mortality and

complication rates as well as a shorter hospital stay in

the epidural group (4). The other showed decreased

duration of mechanical ventilation, reduced overall

hospital charges and a shorter hospital stay (5). While

these are not large randomized controlled trials, they

show clear benefits of epidural analgesia in selected

populations.

We recommend Dr Chalkiadis try this more certain

method of catheter placement before broadly condemning

epidural analgesia in children.

Dr Ramona A. Kearney , M D , F R C P CM D , F R C P C

Associate professor, University of AlbertaDepartment of Anaesthesiology

and Pain MedicineClinical Sciences Building, Room 8-120

Edmonton, Alberta T6G 2B7Canada


References

1 Chalkiadis G. The rise and fall of continuous epidural infusionsin children. Paediatr Anaesth 2003; 13: 91–93.

2 Tsui BCH, Seal R, Koller J et al. Thoracic epidural analgesia viathe caudal approach in pediatric patients undergoing fundo-plication using nerve stimulation guidance. Anesth Analg 2001;93: 1152–1155.

3 Tsui BCH, Wagner A, Cave D et al. Thoracic and lumbarepidurals via caudal using electrical stimulation. Guidance inPediatric Patients: a Review of 289 Patients. Can J Anaesth 2003;50: in press.

4 Wilson GAM, Brown JL, Crabbe DG et al. Is epidural analgesiaassociated with an improved outcome following open Nissenfundoplication? Paediatr Anaesth 2001; 11: 65–70.

5 McNeely JK, Farber NE, Rusy LM et al. Epidural analgesiaimproves outcome following pediatric fundoplication. A retro-spective analysis. Reg Anesth 1997; 22: 16–23.

Response to editorial by Chalkiadis

SIRIR—We read with interest the editorial by Dr Chalkiadis

(1). We in the United Kingdom and Ireland also wish to

determine the incidence of severe complications of

epidural analgesia in children. Thus we have instigated

a multicentre prospective audit of epidural analgesia in

children. We have so far enrolled 3000 patients out of

the 10 000 required. We expect to publish our results in

2005.

A. Moriarty

and Birmingham Children’s Hospital Acute Pain Servicefor and on behalf of the audit participants

Department of AnaesthesiaBirmingham

Children’s HospitalBirmingham, B4 6NH, UK

Reference

1 Chalkiadis G. The rise and fall of continuous epidural infusionsin children. Paediatr Anaesth 2003; 13: 91–93.

Analgesia for cleft lip and palate:comment on Takemura et al.

SIRIR—I read with interest the article ‘Correlation of cleft

type with incidence of perioperative respiratory compli-

cations in infants with cleft lip and palate’ recently

published in Paediatric Anaesthesia (1).

The correlation among the groups of cleft lip and palate,

the assessment of common cold symptoms in the preop-

erative period, using the Common Cold Score and the

perioperative respiratory complications are all most inter-

esting.

However, I am interested to know what form of

analgesia was used for these patients introperatively as

the current trend is to rely more on nerve blocks such as

bilateral infraorbital blocks for the lip repair and pharyn-

geal blocks for the cleft palate repair.

The authors state that the ‘concentration of sevoflurane

was adjusted between 1.5 and 3% to maintain anaesthesia’

but sevoflurane has no analgesic properties and children

require some form of analgesia intraoperatively.

Were opioids used intraoperatively and do the authors

have haemodynamic data (blood pressure, heart rate)

available from the operative period?

Mariano Castilla

Spanish Representative Federation ofEuropean Association

of Paediatric AnaesthesiaDivisional Chief (Consultant)

Paediatric AnaesthesiaChildren’s Hospital Carlos Haya

Ma’laga, Spain(Email: [email protected])

Reference

1 Takemura H, Yasumoto K, Toi T et al. Correlation of cleft typewith incidence of perioperative respiratory complications ininfants with cleft lip and palate. Paediatr Anaesth 2002; 12: 585–588.


646 CORRESPONDENCE

Reply to Dr Castilla

SIRIR—We appreciate the interest and comments of

Dr Castilla in response to our work (1).

We recognize that the analgesic properties of sevoflu-

rane are weak. At light planes of anaesthesia with inhaled

agents, adverse respiratory events such as breatholding,

coughing and laryngeal spasm may occur (2). The dur-

ation of primary plastic surgery for cleft lip and palate

(CLP) is comparatively short, but we do not have a short-

acting opioid. Furthermore, the surgical field coincides

with the upper airway. At extubation, sufficient awareness

and absence of residual muscle relaxation are indispens-

able to prevent any postanaesthesia complications of the

upper airway, which is the reason why we do not

administer opioids or neuromuscular blocking agents

intraoperatively. We have used sevoflurane alone in a

mixture of O2 and N2O in infants who undergo primary

repair of CLP and we adjust the concentration of sevoflu-

rane to between 2.5 and 3% before suture of the skin and

between 1.5 and 2% during skin closure.

We would like to emphasize that we believe that

sevoflurane should be used in high concentrations until

the end of surgery when anaesthetizing infants for CLP

who may be harbouring an upper respiratory tract

infection. As far as judging from intraoperative haemo-

dynamic responses, which we did not show in our paper,

we believe that a sufficient depth of anaesthesia can be

obtained by using this simple technique. Of course, after

establishing the absence of immediate postoperative com-

plications, we administer acetaminophen for the manage-

ment of postoperative pain.

Hiroshi Takemura

Kazumasa Yasumoto

Takashi Toi

Akiyoshi Hosoyamada

Department of AnaesthesiologyShowa University School of Medicine

Shinagawa-ku, Tokyo, Japan(Email: [email protected])

References

1 Takemura H, Yasumoto K, Toi K et al. Correlation of cleft typewith incidence of perioperative respiratory complications ininfants with cleft lip and palate. Paed Anaesth 2002; 12: 585–588.

2 Stanski DR. Monitoring depth of anesthesia. In: Miller RD, ed.Anesthesia, 5th edn. Philadelphia, PA: Churchill Livingstone2000: 1087–1116.

Scented vapours and endtidal inhalationagent monitoring system

SIRIR—Inhalational induction of anaesthesia is commonly

used in paediatric practice. Scented substances with

different flavours are often applied to the inside of the

anaesthesia mask. This makes the mask more acceptable to

the child. We recently noticed that these scents caused the

endtidal agent monitors to display the presence of volatile

agents. This was in spite of the fact that no volatile agent

was present.

It was found to be reproducible. Two different makes

of endtidal agent monitors (Ohmeda 5250 RGM, Lou-

isville, CO, USA and the Datex Capnomac Ultima,

Helsinki, Finland) were tested. It was repeated (with

different flavoured vapours e.g. bubble gum, straw-

berry, watermelon) many times with different rates of

fresh gas flow using new anaesthesia circuit, facemask

and endtidal tubing and more than one anaesthesia

machine and endtidal monitor of each brand. At each

flow rate the agent analyser was adjusted to measure

one of the volatile agent e.g. halothane, sevoflurane,

isoflurane, enflurane and desflurane. All of them

showed very high readings for these agents. All these

repeated experiments were carried out without any

patient involvement.

All these scented oils contained propylene glycol (an

alcohol); and most of them contained alcohol or ethyl

alcohol in addition to artificial flavouring agents.

We performed a literature search and found that

alcohols (ethanol, methanol, isopropanol), methane or

acetone in sampled gases can cause spuriously high

volatile agent readings (1–3). Alcohol vapours present

in the scented vapours affect the accuracy of readings

(4).

Therefore, we would like to caution other practitioners

to be cautious in interpreting endtidal anaesthetic agent

values when scented flavours are used while practicing

anaesthesia.Muhammad B. Rafique

Clinical Instructor TuftsUniversity School of MedicineDepartment of Anesthesiology

Tufts-New England Medical Center750 Washington St., Box 298

Boston, MA 02111USA



CORRESPONDENCE 647

References

1 Dorsch JA, Dorsch SE. Understanding Anesthesia Equipment.Philadelphia: Lippincott, Williams and Wilkins, 1999: 700–704.

2 Foley MA, Wood PA, Peel WJ et al. The effect of exhaled alcoholon the performance on the Datex Capnomac. Anaesthesia 1990;45: 232–234.

3 Guyton DC, Gravenstein N. Infrared analysis of volatileanesthetics: impact of monitor agent setting, volatile mixtureand alcohol. J Clin Monit 1990; 6: 203–206.

4 Yamashita M, Tsuneto S. ‘Normac’ falsely recognizes‘fruit extract’ as an anesthetic agent. Anesthesiology 1987; 66:

97–98.


648 CORRESPONDENCE

comment on matsota et al

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