Anju Aggarwal
Sanjeev Ganguly
V.K. Anand
A.K. Patwari
From
the Division of Pediatric Gastroenterology and
Nutrition,
Department of Pediatrics, Lady Hardinge Medical College and Associated Kalawati Saran. Children's' Hospital,
New Delhi 110 001, India.
Reprint requests: Dr. A.K. Patwari, Professor of Pediatrics,. Flat No. 10, Lady Hardinge
Medical College Campus, New Delhi 110 001, India.
Manuscript received: April 27, 1998; Initial review completed: May 27,
1998; Revision accepted: July 3, 1998
Physicians are frequently faced with the problem of reducing
anxiety, pain and combative behavior in children undergoing procedures
such as endoscopies, colonoscopies, bone marrow aspiration and "lumbar
puncture. For older patients an explanation of procedure, anticipation of pain relief after mild sedation and frequent reassurance usually ensures co-operation. For younger children with heightened levels of anxiety, verbal reassurance is seldom effective in decreasing anticipation to pain and secondary combative behavior. An anxiolytic
sedation is necessary to relieve anxiety as well as complete the
procedure successfully. Hence we conducted a prospective uncontrolled clinical trial to evaluate the efficacy and safety of ketamine, a
dissociative anaesthetic, during pediatric endoscopies and colonoscopies.
Subjects and Methods
Children aged 9 months to 12 years undergoing upper gastrointestinal endoscopies (UGIE) (n=180) and colonoscopies (n=30) from January 1996 to December 1997 were enrolled for this prospective study. These also comprised 16 cases of endoscopic sclerotherapy and 4 cases of endoscopic polypectomy. All these children had not taken anything by mouth four hours prior to the procedure. None of them had any chest infection or evidence of raised intracranial tension. All patients had an intravenous line in place for the duration of procedure. Resuscitation equipment including a resuscitation bag, anesthesia mask of appropriate size, suction catheter, supplemental oxygen and intubation
equipment was immediately available prior to administration of
medication. In addition to the person performing the procedure, a second individual trained in airway management was in attendance to monitor the patient.
After informed consent premedication was given in all patients with intravenous administration of 0.01 mg/kg of atropine 15 min before the procedure (to decrease secretions following ketamine administration) and 0.1 mg/kg of diazepam intravenously 7-8 min before the procedure (to minimize frightening hallucinations or nightmares that might be caused by ketamine). Before starting the procedure an initial dose of 1 mg/kg of ketamine was given intravenously, subsequently a dose of 0.5-1 mg/kg was given after 2-3 minutes if adequate sedation was not achieved.
Subsequent dose of 0.5-1 mg/kg was given in few patients depending on the previous dose and anticipated time to complete the procedure (maximum dose 4 mg/kg). Sedation level, secretions during the procedure and postsedation events were given scores according to the scales as shown in
Table
I.
Patients were considered to be adequately sedated if they allowed the procedure to be carried out without much resistance. Heart rate, respiratory rate and blood pressure was recorded at onset and completion of the procedure and children were observed for any sign of respiratory depression during the procedures. End point of recovery was taken as recovery from unconsciousness. After the procedure the patient was monitored by nursing staff until able to walk (if age appropriate), drink clear liquids (if desired by patients and if not nauseated), and give age appropriate response to verbal commands.
TABLE 1
Scales
for Evaluation of Sedation/
Secretion/Post Sedation Events.
|
Sedation |
Score |
|
Awake |
0 |
|
Drowsy but irritable and combative |
1 |
|
Drowsy and restless |
2 |
|
Well sedated for most of the procedure |
3 |
|
Well sedated throughout the procedure |
4 |
|
Secretions |
|
Absent |
0 |
|
Acceptable |
1 |
|
Too much and interfering with the procedure |
2 |
|
Post Sedation Events |
|
Smooth Recovery |
0 |
|
Hallucination/Irrelevant Talking |
1 |
|
Headache |
2 |
|
Others |
3 |
Results
Among the 210 children studied 28 (13.33%) were less than 3 years of
age, 68 (32.38%) between 4-6 years, 58 (27.6%) between 7-9 years and 56 (26.66%) between 9-12 years of age. Age range was 9 months to 12 years with a median age of 6 years. All patients were adequately sedated for successful conduction of 210 procedures studied. Dose of ketamine required was 1 mg/kg for 140/180 (77.77%) of UGIE while 36/180 (20%) required a dose of 1-2 mg/kg and 4/180 (2,2%) required >2 mg/kg (mean
± SD 1.1 ± 0.3 mg). In contrast, only 46.6% (14/30) colonoscopies were successfully carried out with a dose of 1 mg/kg of ketamine,
11 (36.6%) with 1-2 mg/kg and in 5 (16.6%) a dose of >2 mg/kg was required (mean
± SD 1.4 ± 0.42 mg). Scores of quality of sedation, secretions and postsedation events are shown in Table II. Duration of procedure was 15
± 2.2 min in case of UGIE and 25 ± 3.5 min in case of colonoscopies.
Longest duration of the procedure was 35 min. Majority (90%) had smooth recovery from ketamine
sedation. Vomiting during recovery was seen in 2 patients, 5 had appearance of a transient maculopapular rash and 1 patient had puffiness of eyelids. Tachycardia was observed in most of the cases but the respiratory
rate and blood pressure remained nor- mal during and after completion
of the procedure. No patient had wheezing or any sign suggestive of laryngospasm. There was no episode of aspiration during sedation though
silent aspiration cannot be ruled out. All patients were awake by the
time of completion of procedure and majority had complete recovery from unconsciousness within 15.4
± 2.2 min.
TABLE
II
Efficacy
of Ketarnine (Sedation/Secretion/Post Sedation Scores)
|
Parameters |
Scores |
Upper GI Endoscopics (n=180) No. (%) |
Colonoscopies
(n=30)
No. (%) |
| Sedation |
0 |
0 (0) |
0 (0) |
| |
1 |
8 (4.4) |
1 (3.3) |
| |
2 |
33 (12.8) |
0 (0) |
| |
3 |
123 (68.3) |
27 (90) |
| |
4 |
26 (14.4) |
2 (6.6) |
| Secretions |
0 |
8 (4.4) |
5 (16.7) |
| |
1 |
163 (90.55) |
25 (83.3) |
| |
2 |
9 (5) |
9 (0) |
| Post Sedation |
0 |
162 (90) |
27 (90) |
| |
1 |
10 (5.5) |
2 (6.7) |
| |
2 |
1 (0.6) |
0 (0) |
| |
3 |
7 (3.9) |
1 (3.3) |
Discussion
Endoscopic procedures cause consider- able discomfort which is aggravated in
struggling children who are often fretful and tense. Children who are repeatedly subjected to endoscopic procedures, e.g., endoscopic sclerotherapy, are even more tense because of their previous experience. Therefore, it is inappropriate to subject children to distressing procedures if it can be avoided. Moreover, many therapeutic procedures maybe difficult or unsafe in an uncooperative child. Commonly used sedatives like, chloral hydrate and benzodiazepines are largely ineffective in alleyiating pain and anxiety in these situations.
Ketamine is a nonbarbiturate, phenocyclidine derivative that produces a unique
combination of aneshtesia, analgesia, sedation and amnesia. It produces a
functional and electrophysiological dissociation between cortical and limbic system. It provides analgesia but patients keep their eyes open and all protective reflexes are maintained. The intravenous anesthetic dose is 1-2 mg/kg which causes only a
moderate decrease in PO2 but CO2 responsiveness is maintained. Children require slightly higher plasma levels compared to adults and there is marked interindividual variability regarding the dose of ketamine
required. Recovery from unconsciousness is seen within 15-20
minutes after single intravenous anesthetic dose. However, recovery from amnesia occurs in one to two hours and analgesia persists for even longer
time(1). Efficacy of ketamine alone and ketamine with benzodiazepines has been proved in various pediatric procedures(2-4). When ketamine is used as a single agent there is significant incidence of dysmorphic reactions and emergence phenomenon. The use of benzodiazepines with ketamine
results in more rapid onset of analgesia, fewer and less severe dysmorphic reactions, more amnesia of procedure a need for lesser dose of ketamine and a lesser risk of respiratory depression from low dose of benzodiazepine needed for sedation(3-5). In our experience ketamine sedation with atropine and diazepam as premedication provided safe and effective sedation for pediatric endoscopic procedures.
Majority of UGIE procedures (77.77%) were carried out using 1 mg/kg of ketamine
and only 2.8% required a dose >2 mg/kg in contrast to
colonoscopies where 53.4% required a dose of >1 mg/kg and 16.6% a
dose >2 mg/kg. This is due to the fact that the' time required for
colonoscopies is longer than upper gastrointestinal endoscopies. During most of
procedures patients were adequately sedated, i.e., allowed the procedure to be
carried out comfortably and the procedure was not abandoned in any case. There was smooth recovery from sedation in 90% of the procedures. Incidence of hallucinations and irrelevant talking (5.7%) is similar to a study using a combination of midazolam
and ketamine(3). There was no significant respiratory or cardiovascular effect of the drug. No patient had respiratory depression or laryngospasm. Oxygen saturation measurement has been recommended for monitoring 'patients undergoing gastrointestinal
endoscopies under sedation. It was not possible for us to
undertake oxygen saturation measurement in our patients due to lack of facilities. Nevertheless, it has been demonstrated in previous studies(2,3,4,6) that ketamine sedation causes a transient fall in oxygen satunition
below 85% in only 1-2% of patients. This fall is related to posture during the procedure, e.g., obesity or neck flexion during .lumbar puncture. These studies have concluded that young and healthy patients maintain normal oxygen saturation during ketamine anaesthesia on room air provided airway patency is maintained.
Secretions interfered with the procedure in only 5% of UGIE and required frequent suctioning.. Other reported(1) side effects of intravenous ketamine, namely, laryngospasm,
skeletal muscle hypertonicity, hypertension, myoclonus and twitching movements were not seen during. the procedures studies. Five cases (2.4%) had a transient maculopapular rash with puffiness of eye lids. Similar rash has been reported to be associated with ketamine in 12% of patients in a previous study(3) though no explanation is available for this side effect.
Ketamine provided adequate sedation and analgesia without any significant side effects in majority of pediatric endoscopic procedures studied by us. Hence ketamine can be used as a safe and effective anesthetic agent during pediatric endoscopic
procedures without any extensive monitoring system. However, it should be used with caution and the risk of progression to deeper sedation with loss of airway protective reflexes and respiratory depression should be anticipated. Personnel trained to intubate should be present during the procedure and facilities for administration of oxygen, intubation and ventilation should also be available during ketamine anesthesia.
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