ANESTH ANALG 1990;71:511-5
511
Comparison of Propofol and ThiopentaVHalothane for ShortDuration ENT Surgical Procedures in Children A. Borgeat,
MD,
V. Popovic,
MD,
D. Meier,
MD,
BORGEAT A, POPOVIC V, MElER D, SCHWANDER D. Comparison of propofol and thiopental/halothane for short-duration ENT surgical procedures in children. Anesth Analg 1990;71:511-5.
Experiences with propofol in pediatric anesthesia are lirnited. W e undertook a study to evaluate the quality of induction and recovery from anesthesia with propofol cornpared to thiopentallhalothane. Twenty children received 3 mg.kg-I.min-' of propofol as a loading dose followed by a maintenance dose of 0.1 mg.kg-'.inin-' (tlOlo). Twenty children received 5-7 mglkg of thiopental, and maintenance was provided with halothane (0.5%-1.5%). The interval between the end of the administration of propofol or thiopentallhalothane and extubation, as zvell to discharge to the
Propofol is a relatively new intravenous anesthetic (1) for induction and maintenance of anesthesia. It has many advantages, including pharmacokinetic properties contributing to rapid induction and recovery times (2,3). In contrast to studies in adults, there is little experience with propofol in pediatric anesthesia. Therefore we undertook a study to evaluate the quality of induction and recovery from anesthesia with propofol compared to thiopental/halothane in children having ear, nose, or throat (ENT) surgery of short duration.
Patients and Methods Forty children aged 3-8 yr were studied after hospital ethics committee approval had been obtained. Pa-
Supported in part by ICI Pharmaceutical Division, Lucerne, Switzerland. Received from the Service d'anesthesiologie-reanimation et d'otorhinolaryngologie, HBpital Cantonal de Fribourg, CH 1700 Fribourg, Switzerland. Accepted for publication June 24, 1990. Address correspondence to Dr. Borgeat, Service danesthesiologie-reanimation, HBpital Cantonal Universitaire de Geneve, 121 1 Geneve 4, Switzerland. 01990 by the International Anesthesia Research Society
and D. Schwander, MD ward, was significantly shorter with propofol (4.4 aersus 13.5 min and 7.22 versus 30.4 miii, respectively). Spontaneous movements and pain on injectioii were seeri significaiitly more frequently with propofol, whereas laryngospasm and hiccup were only observed with thiopental. During the first 6 h after the surgical procedure, analgesics u w e needed significantly more ofteii in the thiopental group. Nausea and vomiting also were observed more frequently in the thiopental group. In conclusion, propofol used as a s i n ~ l eanesthetic is a satisfactory technique for ENT surgery of short duration in children. Key Words: ANESTHESIA, PEDIATRIC-PrOPOfOl,
thiopental. ANESTHETICS, INTRAVENOUSpropofol, thiopental.
tients were ASA physical status I and were scheduled for short elective ENT procedures. Exclusion criteria included known allergy to the anesthetic drugs or their constituents, a history of previous adverse experience to general anesthesia, the presence of psychomotor retardation, and general anesthesia with halothane within the last 3 mo. All patients were premedicated with 0.04 mg/kg oral atropine 60 min before operation. On arrival in the anesthetic room, heart rate and systolic and diastolic blood pressures were recorded using an automatic device (Cardiocap Datex, Helsinki). Other monitors included an electrocardiograph, a pulse oximeter (Cardiocap Datex, Helsinki), a nerve stimulator (Dual Stim, Houston, Tex.), and a precordial stethoscope. A 20- or 22-gauge catheter was inserted into a vein on the dorsum of the hand or in the antecubital fossa. Children were randomly allocated in an open study to either group A (propofol) or group B (thiopental/halothane). All patients were preoxygenated with 100% oxygen for 1 min. Group A received a loading dose of 3 mg/kg IV propofol immediately followed by a continuous infusion of 0.1 mg. kg-l-rnin-' (+lo%) using an automatic pump (WAC
512
BORGEAT ET AL.
ANESTH ANALG lWO;71:511-5
711, San Diego, Calif.). Group B patients were given 5-7 mg/kg thiopental with maintenance of anesthesia provided by halothane (0.5%-1.5%). Tracheal intubation was facilitated with 0.1 mgkg IV vecuronium in both groups. A supplemental dose of vecuronium (one-third to one-fourth the initial dose) was given when necessary either as judged by the surgeon or as indicated by reappearance of more than two twitches out of four (nerve stimulator). Anesthetic depth was considered adequate if heart rate and blood pressure were maintained within 20% of preinduction values, with propofol and halothane concentrations adjusted as necessary for pressure and pulse rate to remain within this limit. Manual ventilation with 33% oxygen and 66% nitrous oxide was used in all patients. Hemoglobin saturation (Sao,) never decreased below 95%, and the end-tidal carbon dioxide tension (PEco~)was kept between 35 and 40 mm Hg. At the end of surgery the neuromuscular blockade was reversed with 0.02 mg/kg atropine and 0.04 mg/kg prostigmine. Propofol, halothane, and nitrous oxide were discontinued as soon as the surgeon had terminated the operation (time "0" of the recovery period). The following conditions had to be fulfilled before extubation: four twitches before reversal of the neuromuscular blockade; spontaneous coordinated movements of the arms; pupils normally dilated and central; spontaneous respiration (PECO,less than 45 mm Hg and Sao, greater than 95% with 100% oxygen); and opening of the eyes either on command or spontaneously. Stimulation was not permitted except gentle endobuccal suction when necessary. After extubation the children were transferred to the recovery room, where the awakening was assessed. The following criteria for discharge to the ward had to be fulfilled: the child had to be awake and alert, able to sit unaided, and able to communicate according to age and to execute simple orders. The recovery room nurses were responsible for the transfer of the children to the ward (according to the discharge criteria) and were not informed of the anesthetic drugs used. Neither opiates nor benzodiazepines were given either as premedication or during surgery. Statistical analysis of the results was carried out using a nonparametric approach with the MannWhitney test and /J with Yates' correction for small numbers when appropriate. Student's t-test was used to compare demographic data. Results are given as mean f SEM. P < 0.05 was considered as significant.
Table 1. Characteristics of Patients Propofol group 20
n Age (yr)
6.09
? 1.64 (3-8)
Weight (kg) Sex (M/F) Operating time (min) Type of surgery Adenoidectom y Tonsillectomy Adenoidectomy and tonsillectomy Other
Thiopental/halothane group 20 5.11 2 2.26
(W
20.5 ? 9.07 (16-32) 9/11 37 ? 12.1
21.5 2 5.96 (14.&30) 8/12 34.9 5 11.35
6 7 5
5 8 7
" L
~
Values for age, weight, and operating time are mean t SD. Ranges are given in parentheses.
Table 2. Interval Between End of Drug Administration and Extubation and Discharge From the Recovery Room Propofol gro" P Time to extubation (min) Time to discharge from recovery room (min) Values are mean
4.4 ? 0.74 7.22 ? 0.59
ThiopentaUhalothane group 13.5 ? 2.32 30.4 2 4.03
2 SEM
Results The ages, weights, sex, duration, and type of surgical procedures were similar in both groups (Table 1). There were 23 girls and 17 boys. The interval between the end of the administration of propofol or halothane and extubation was significantly shorter in group A (propofol): 4.4 .t 0.74 min versus 13.5 2 2.30 rnin (P < 0.005) in group B (halothane) (Table 2). In group A, all patients fulfilled the extubation criteria, whereas in group B 16 of the 20 patients (80%) did not open their eyes before extubation. However, extubation had to be performed because of coughing and struggling due to the presence of the endotracheal tube. The time between the end of the administration of propofol or halothane and the completion of the criteria for discharge from the recovery room was also significantly shorter with propofol (7.22 t 0.59 min) than with thiopental/halothane (30.4 4.03 min) (P < 0.005) (Table 2). During induction in the propofol group, mean arterial pressure decreased 11.2% after 1 min to a maximum of 14.3% after 2 min. Heart rate remained stable or showed a slight decrease of 5%-10% of preinduction values. In the thiopental group mean
*
PROPOFOL VERSUS THlOPENTALlHALOTHANE IN CHILDREN
Table 3. Incidence of Side Effects During Induction Side effect Pain Spontaneous movements Laryngospasm Hiccup
Propofol group 5 (25%) 15 (75%)
-
ThiopentaVhalothane group 4 (20%) 1(5%) 1 ( 5%)
Table 4. Quality of Awakening Activity Agitated, uncooperative, crying Nausea, emesis Need for analgesic
Propofol group
ThiopentaVhaIothane group
1(5%)
14 (70%)
-
2 (10%) 9 (4590)
1(5%)
arterial pressure decreased by 13.5% after 1 min to a maximum of 15% after 90 s, whereas heart rate showed a slight increase of 8%-12% of preinduction values. During maintenance of anesthesia in both groups, heart rate and blood pressure remained stable and were easily adjusted by slight increase or decrease of perfusion rate of propofol or percentage of halothane. Side effects during induction are summarized in Table 3. In group B pain was not experienced. In group A the incidence of pain on injection was 25%. Four of the children who had pain on injection had a 22-gauge catheter inserted in the dorsum of the hand; one had a 22-gauge catheter in a small vein in the antecubital fossa. Spontaneous movements occurred during induction in 75% of children receiving propofol and in 20% receiving thiopental. Laryngospasm and hiccup occurred in one child in group B (halothane). Quality of recovery was excellent in all children in group A, except for one who cried, whereas 70% of the patients in group B were described as agitated, uncooperative, and crying. During the first six postoperative hours analgesics were needed in one child in group A (5%)and in nine (45%)in group B. Nausea and emesis were absent in group A but occurred in two children (10%) in group B (Table 4). All children in the propofol group were able to recall within 4 min of extubation the picture of a familiar animal (cat, dog) shown to them before induction.
Discussion Recovery after propofol, one of the striking features of this drug, has been commented on by many
ANESTH ANALG 1990;71:511-5
513
investigators: rapid emergence and minimal postoperative confusion are characteristic (4-7). However, the vast majority of studies of recovery from propofol have been carried out in adults. The present study shows that the quality of recovery in children after short-duration ENT surgery using propofol as a principal agent is very satisfactory. The intervals between cessation of drug administration and both extubation and transfer from the recovery room to the ward were significantly shorter with propofol than with thiopental/halothane: 4.47 versus 13.5 rnin and 7.22 versus 30.4 min, respectively. In adults undergoing relatively brief operations, the mean interval between cessation of propofol and extubation was 11 min (8); however, these patients were premedicated with oral diazepam (10 mg), and the first-stage elimination half-life (tl,,p) of propofol is shorter in children (9). Using criteria similar to ours (pediatric outpatient dental anesthesia), Puttick and Rosen (10) found a mean recovery time of 22 min with propofol and 29 min with thiopental/halothane, findings similar to ours. The shorter recovery time found in our study could be explained in part by the advantage of a continuous infusion compared with a supplemental bolus administration technique. Indeed, continuous intravenous infusion showed little accumulation, and thus clinical effects are predictable, e.g., consistently rapid recovery (11,12). All children, except the one who cried, were quiet, well oriented and coordinated, and cooperative in the recovery room, whereas 70% of patients in the thiopental/halothane group were crying, agitated, uncoordinated, and uncooperative during the first 20 min. Previous studies have demonstrated that children may need larger induction doses of propofol than adults (13,14). Purcell-Jones and James (15) showed that a dose of 2.0 mg/kg in premedicated children was not always sufficient for a smooth induction. Also, Valtonen et al. (14) were not entirely satisfied with a loading dose of 2.0-2.5 mg/kg in premedicated children. Because premedication has little effect on the smoothness of induction (16), we chose a dose of 3 mg/kg for this study. Even though atropine was the only drug used for premedication, only four children exhibited signs of anxiety and fear before induction. The incidence of pain on injection in adults has been reduced by the use of a fat emulsion as a vehicle for propofol (17). We found a 25% incidence of pain with propofol and none with thiopental. These results are similar to those of Purcell-Jones et al. (24% for propofol and 10% for thiopental) (13). The incidence of pain on injection in adults is higher when the smaller veins on the dorsum of the hand are used
514
BORGEAT ET AL.
ANESTH ANALG 1990;71:511-5
(18,19).Children had a 30% incidence of pain according to Saint-Maurice et al. (20). In their study, pain was associated with the size of the vein used, which we also noted. All five children who experienced pain on injection had a 22-gauge catheter (the smallest size used in this study). The catheter was inserted in four cases in the dorsum of the hand and in the fifth case in a small vein of the antecubital fossa. Addition of lidocaine to propofol decreases pain on injection (9,10), but the role of premedication, including use of analgesics, is not yet clear. Spontaneous movements have been reported in 14%-33%(21,22) of adults. Our observation of 75%is greater than that reported by Fahy et al. in premedicated adults (22) and Purcell-Jones et al. (33%)(13), but similar to the 65% incidence observed by PurcellJones and James (15); however, in the latter study the loading dose of propofol was small (2 mg/kg). All of these movements, however, were minor in our study, appearing a few seconds after the completion of injection and lasting no longer than 25 s. SaintMaurice et al. (20) suggest a possible inadequate anesthesia when using a loading dose of 2-2.5 mg/kg of propofol. The influence of premedication and the speed of injection on the incidence of spontaneous movements is not clear; further studies are needed to evaluate whether inadequate anesthesia and central or peripheral stimulation are involved in the genesis of spontaneous movements during induction with propofol. The number of patients with spontaneous motion is smaller (20%)in the thiopental group, as previously reported (13,14). Hiccup and laryngospasm were observed in two children receiving thiopental and in none given propofol; this tendency is also similar to published data (14). Side effects such as pain or nausea and emesis were less frequent during the first postoperative hours in the propofol group. This was also reported by McCollum and colleagues (23), who found less nausea and vomiting after induction with propofol than after induction with methohexital. Briggs and colleagues (24) suggested that propofol produces some analgesic effect, contrary to the antianalgesic effect of thiopental; it is interesting that in the present study only one child needed an analgesic postoperatively in the propofol group whereas nine children in the thiopental/halothane group needed an analgesic. In conclusion, previous studies dealing with children have stressed induction characteristics (9,15), combined use of propofol and inhaled anesthetics (13,14,20), or propofol given by bolus (10). The present study shows that continuous perfusion of propofol is a safe and more effective anesthetic technique than the usual thiopentaVhalothane combina-
tion for short-duration ENT procedures in children. The rapidity and quality of awakening after propofol is superior to that observed after thiopentall halothane administration. The incidence of spontaneous movements and pain on injection is greater with propofol than with thiopental. On the other hand, excitatory side effects such as hiccup or laryngospasm were more frequently observed in the thiopental group. Further studies are needed to find a means of reducing the pain on injection associated with propofol and to understand more completely the process of spontaneous movements associated with the use of propofol for induction in children. The authors thank James Grainger for his help in the preparation of the manuscript.
References 1. Kay B, Rolly C. I.C.I. 35868, a new intravenous induction agent. Acta Anaesthesiol Belg 1977;28:30>16. 2. Nightingale P, Healy TES, Hargreaves J, McGuiness K, Kay 8. Propofol in emulsion form: induction characteristics and venous sequelae. Eur J Anaesthesiol 1985;2:361-8. 3. Cockshott ID. Propofol pharmacokinetics and metabolism-an overview. Postgrad Med 1985;61(Suppl3):45-50. 4. Mackenzie N, Grant, IS. Comparison of propofol with methohexitone in the provision of anaesthesia for surgery under regional blockade. Br J Anaesth 1985;57:1167-72. 5. Johnston R, Noseworthy T, Anderson 8, Konopad E, Grace M. Propofol versus thiopental for outpatient anesthesia. Anesthesiology 1987;67:431-3. 6. Mackenzie N, Grant IS. Propofol (“Diprivan“) for continuous intravenous anesthesia. A comparison with methohexitone. Postgrad Med J 1987;6l(Suppl):70-5. 7. Grant IS, Mackenzie N. Recovery following propofol (“Diprivan”) anesthesia-a review of three different anaesthetic techniques. Postgrad Med J 1985;61(Suppl):133-7. 8. Queruel PL, Francon D, Lacorelle 8 , Francois G. Le reveil apres anesthesie au propofol pour chirurgie ORL de courte duree. Ann Fr Anesth Reanim 1987;273-6. 9. Valtonen M, Iisalo E, Kanto J, Rosenberg P. Propofol as an induction agent in children: pain on injection and pharmacokinetics. Acta Anaesthesiol Scand 1989;33:152-5. 10. Puttick N, Rosen M. Propofol induction and maintenance with nitrous oxide in paediatric outpatient dental anaesthesia. A comparison with thiopental-nitrous oxide-halothane. Anaesthesia 1988;43:646-9. 11. Jessop E, Grounds RM, Morgan M, Lumley L. Comparison of infusions of propofol and methohexitone to provide light general anesthesia during surgery with regional block. Br J Anaesth 1985;57:1173-7. 12. Kay 8, Hargreaves J, Sivalingam T, Healy TEJ. Intravenous anesthesia for cystoscopy: a comparison of propofol or methohexitone with alfentanil. Eur J Anaesthesiol 1986;3:111-20. 13. Purcell-Jones G, Yates A, Baker JR, James IG. Comparison of the induction characteristics of thiopentone and propofol in children. Br J Anaesth 1987;59:1431-6.
PROPOFOL VERSUS THIOPENTALiHALOTHANE IN CHILDREN
14. Valtonen M, lisalo E, Kanto J, Tikkanen J. Comparison of propofol and thiopentone for induction of anaesthesia in children. Anaesthesia 1988;43:696-9. 15. Purcell-Jones G, James IG. The characteristics of propofol ("Diprivan") for the induction of general anesthesia for paediatric surgery. Postgrad Med J 1985;6l(Suppl 3):115. 16. Glen JB, Hunter SC. Pharmacology of an emulsion formulation of ICI 35 868. Br J Anaesth 1984;56:617-25. 17. Cummings GC, Spence AA. Comparison of propofol in emulsion with althesin for induction of anesthesia. Br J Anaesth 1985;57:2345. 18. Kawar P, Dundee JW. Frequency of pain on injection and venous sequelae following the IV administration of certain anaesthetics and sedatives. Br J Anaesth 1982;54:9359. 19. Mackenzie N, Grant IS. Comparison of the new emulsion formulation of propofol with methohexitone and thiopentone
ANESTH ANALG 1990:71:511-5
20.
21.
22.
23. 24.
515
for inducing anaesthesia in day-cases. Br J Anaesth 1985;57: 725-31. Saint-Maurice C, Landais A, Cockshott ID, et al. Le propofol comme agent d'induction en anesthesie pediatrique: etude clinique preliminaire. Ann Fr Anesth Reanim 1987;6:269-72. Stark RD, Binks SM, Dutka VN, OConnor KM, Arnstein MJA, Glen JB. A review of the safety and tolerance of propofol. Postgrad Med J 1985;61:152-6. Fahy LT, Van Mourik GA, Utting JE. A comparison of the induction characteristics of thiopentone and propofol. Anaesthesia 1985;40:939-44. McCollum JS, Milligan KR, Dundee JW. The antiemetic action of propofol. Anaesthesia 1988;43:23940. Briggs LP, Dundee JW, Bahar M, Clarke RSS. Comparison of the effect of diisopropyl phenol (ICI 35868) and thiopentone on response to somatic pain. Br J Anaesth 1982;54:307-11.
511
Comparison of Propofol and ThiopentaVHalothane for ShortDuration ENT Surgical Procedures in Children A. Borgeat,
MD,
V. Popovic,
MD,
D. Meier,
MD,
BORGEAT A, POPOVIC V, MElER D, SCHWANDER D. Comparison of propofol and thiopental/halothane for short-duration ENT surgical procedures in children. Anesth Analg 1990;71:511-5.
Experiences with propofol in pediatric anesthesia are lirnited. W e undertook a study to evaluate the quality of induction and recovery from anesthesia with propofol cornpared to thiopentallhalothane. Twenty children received 3 mg.kg-I.min-' of propofol as a loading dose followed by a maintenance dose of 0.1 mg.kg-'.inin-' (tlOlo). Twenty children received 5-7 mglkg of thiopental, and maintenance was provided with halothane (0.5%-1.5%). The interval between the end of the administration of propofol or thiopentallhalothane and extubation, as zvell to discharge to the
Propofol is a relatively new intravenous anesthetic (1) for induction and maintenance of anesthesia. It has many advantages, including pharmacokinetic properties contributing to rapid induction and recovery times (2,3). In contrast to studies in adults, there is little experience with propofol in pediatric anesthesia. Therefore we undertook a study to evaluate the quality of induction and recovery from anesthesia with propofol compared to thiopental/halothane in children having ear, nose, or throat (ENT) surgery of short duration.
Patients and Methods Forty children aged 3-8 yr were studied after hospital ethics committee approval had been obtained. Pa-
Supported in part by ICI Pharmaceutical Division, Lucerne, Switzerland. Received from the Service d'anesthesiologie-reanimation et d'otorhinolaryngologie, HBpital Cantonal de Fribourg, CH 1700 Fribourg, Switzerland. Accepted for publication June 24, 1990. Address correspondence to Dr. Borgeat, Service danesthesiologie-reanimation, HBpital Cantonal Universitaire de Geneve, 121 1 Geneve 4, Switzerland. 01990 by the International Anesthesia Research Society
and D. Schwander, MD ward, was significantly shorter with propofol (4.4 aersus 13.5 min and 7.22 versus 30.4 miii, respectively). Spontaneous movements and pain on injectioii were seeri significaiitly more frequently with propofol, whereas laryngospasm and hiccup were only observed with thiopental. During the first 6 h after the surgical procedure, analgesics u w e needed significantly more ofteii in the thiopental group. Nausea and vomiting also were observed more frequently in the thiopental group. In conclusion, propofol used as a s i n ~ l eanesthetic is a satisfactory technique for ENT surgery of short duration in children. Key Words: ANESTHESIA, PEDIATRIC-PrOPOfOl,
thiopental. ANESTHETICS, INTRAVENOUSpropofol, thiopental.
tients were ASA physical status I and were scheduled for short elective ENT procedures. Exclusion criteria included known allergy to the anesthetic drugs or their constituents, a history of previous adverse experience to general anesthesia, the presence of psychomotor retardation, and general anesthesia with halothane within the last 3 mo. All patients were premedicated with 0.04 mg/kg oral atropine 60 min before operation. On arrival in the anesthetic room, heart rate and systolic and diastolic blood pressures were recorded using an automatic device (Cardiocap Datex, Helsinki). Other monitors included an electrocardiograph, a pulse oximeter (Cardiocap Datex, Helsinki), a nerve stimulator (Dual Stim, Houston, Tex.), and a precordial stethoscope. A 20- or 22-gauge catheter was inserted into a vein on the dorsum of the hand or in the antecubital fossa. Children were randomly allocated in an open study to either group A (propofol) or group B (thiopental/halothane). All patients were preoxygenated with 100% oxygen for 1 min. Group A received a loading dose of 3 mg/kg IV propofol immediately followed by a continuous infusion of 0.1 mg. kg-l-rnin-' (+lo%) using an automatic pump (WAC
512
BORGEAT ET AL.
ANESTH ANALG lWO;71:511-5
711, San Diego, Calif.). Group B patients were given 5-7 mg/kg thiopental with maintenance of anesthesia provided by halothane (0.5%-1.5%). Tracheal intubation was facilitated with 0.1 mgkg IV vecuronium in both groups. A supplemental dose of vecuronium (one-third to one-fourth the initial dose) was given when necessary either as judged by the surgeon or as indicated by reappearance of more than two twitches out of four (nerve stimulator). Anesthetic depth was considered adequate if heart rate and blood pressure were maintained within 20% of preinduction values, with propofol and halothane concentrations adjusted as necessary for pressure and pulse rate to remain within this limit. Manual ventilation with 33% oxygen and 66% nitrous oxide was used in all patients. Hemoglobin saturation (Sao,) never decreased below 95%, and the end-tidal carbon dioxide tension (PEco~)was kept between 35 and 40 mm Hg. At the end of surgery the neuromuscular blockade was reversed with 0.02 mg/kg atropine and 0.04 mg/kg prostigmine. Propofol, halothane, and nitrous oxide were discontinued as soon as the surgeon had terminated the operation (time "0" of the recovery period). The following conditions had to be fulfilled before extubation: four twitches before reversal of the neuromuscular blockade; spontaneous coordinated movements of the arms; pupils normally dilated and central; spontaneous respiration (PECO,less than 45 mm Hg and Sao, greater than 95% with 100% oxygen); and opening of the eyes either on command or spontaneously. Stimulation was not permitted except gentle endobuccal suction when necessary. After extubation the children were transferred to the recovery room, where the awakening was assessed. The following criteria for discharge to the ward had to be fulfilled: the child had to be awake and alert, able to sit unaided, and able to communicate according to age and to execute simple orders. The recovery room nurses were responsible for the transfer of the children to the ward (according to the discharge criteria) and were not informed of the anesthetic drugs used. Neither opiates nor benzodiazepines were given either as premedication or during surgery. Statistical analysis of the results was carried out using a nonparametric approach with the MannWhitney test and /J with Yates' correction for small numbers when appropriate. Student's t-test was used to compare demographic data. Results are given as mean f SEM. P < 0.05 was considered as significant.
Table 1. Characteristics of Patients Propofol group 20
n Age (yr)
6.09
? 1.64 (3-8)
Weight (kg) Sex (M/F) Operating time (min) Type of surgery Adenoidectom y Tonsillectomy Adenoidectomy and tonsillectomy Other
Thiopental/halothane group 20 5.11 2 2.26
(W
20.5 ? 9.07 (16-32) 9/11 37 ? 12.1
21.5 2 5.96 (14.&30) 8/12 34.9 5 11.35
6 7 5
5 8 7
" L
~
Values for age, weight, and operating time are mean t SD. Ranges are given in parentheses.
Table 2. Interval Between End of Drug Administration and Extubation and Discharge From the Recovery Room Propofol gro" P Time to extubation (min) Time to discharge from recovery room (min) Values are mean
4.4 ? 0.74 7.22 ? 0.59
ThiopentaUhalothane group 13.5 ? 2.32 30.4 2 4.03
2 SEM
Results The ages, weights, sex, duration, and type of surgical procedures were similar in both groups (Table 1). There were 23 girls and 17 boys. The interval between the end of the administration of propofol or halothane and extubation was significantly shorter in group A (propofol): 4.4 .t 0.74 min versus 13.5 2 2.30 rnin (P < 0.005) in group B (halothane) (Table 2). In group A, all patients fulfilled the extubation criteria, whereas in group B 16 of the 20 patients (80%) did not open their eyes before extubation. However, extubation had to be performed because of coughing and struggling due to the presence of the endotracheal tube. The time between the end of the administration of propofol or halothane and the completion of the criteria for discharge from the recovery room was also significantly shorter with propofol (7.22 t 0.59 min) than with thiopental/halothane (30.4 4.03 min) (P < 0.005) (Table 2). During induction in the propofol group, mean arterial pressure decreased 11.2% after 1 min to a maximum of 14.3% after 2 min. Heart rate remained stable or showed a slight decrease of 5%-10% of preinduction values. In the thiopental group mean
*
PROPOFOL VERSUS THlOPENTALlHALOTHANE IN CHILDREN
Table 3. Incidence of Side Effects During Induction Side effect Pain Spontaneous movements Laryngospasm Hiccup
Propofol group 5 (25%) 15 (75%)
-
ThiopentaVhalothane group 4 (20%) 1(5%) 1 ( 5%)
Table 4. Quality of Awakening Activity Agitated, uncooperative, crying Nausea, emesis Need for analgesic
Propofol group
ThiopentaVhaIothane group
1(5%)
14 (70%)
-
2 (10%) 9 (4590)
1(5%)
arterial pressure decreased by 13.5% after 1 min to a maximum of 15% after 90 s, whereas heart rate showed a slight increase of 8%-12% of preinduction values. During maintenance of anesthesia in both groups, heart rate and blood pressure remained stable and were easily adjusted by slight increase or decrease of perfusion rate of propofol or percentage of halothane. Side effects during induction are summarized in Table 3. In group B pain was not experienced. In group A the incidence of pain on injection was 25%. Four of the children who had pain on injection had a 22-gauge catheter inserted in the dorsum of the hand; one had a 22-gauge catheter in a small vein in the antecubital fossa. Spontaneous movements occurred during induction in 75% of children receiving propofol and in 20% receiving thiopental. Laryngospasm and hiccup occurred in one child in group B (halothane). Quality of recovery was excellent in all children in group A, except for one who cried, whereas 70% of the patients in group B were described as agitated, uncooperative, and crying. During the first six postoperative hours analgesics were needed in one child in group A (5%)and in nine (45%)in group B. Nausea and emesis were absent in group A but occurred in two children (10%) in group B (Table 4). All children in the propofol group were able to recall within 4 min of extubation the picture of a familiar animal (cat, dog) shown to them before induction.
Discussion Recovery after propofol, one of the striking features of this drug, has been commented on by many
ANESTH ANALG 1990;71:511-5
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investigators: rapid emergence and minimal postoperative confusion are characteristic (4-7). However, the vast majority of studies of recovery from propofol have been carried out in adults. The present study shows that the quality of recovery in children after short-duration ENT surgery using propofol as a principal agent is very satisfactory. The intervals between cessation of drug administration and both extubation and transfer from the recovery room to the ward were significantly shorter with propofol than with thiopental/halothane: 4.47 versus 13.5 rnin and 7.22 versus 30.4 min, respectively. In adults undergoing relatively brief operations, the mean interval between cessation of propofol and extubation was 11 min (8); however, these patients were premedicated with oral diazepam (10 mg), and the first-stage elimination half-life (tl,,p) of propofol is shorter in children (9). Using criteria similar to ours (pediatric outpatient dental anesthesia), Puttick and Rosen (10) found a mean recovery time of 22 min with propofol and 29 min with thiopental/halothane, findings similar to ours. The shorter recovery time found in our study could be explained in part by the advantage of a continuous infusion compared with a supplemental bolus administration technique. Indeed, continuous intravenous infusion showed little accumulation, and thus clinical effects are predictable, e.g., consistently rapid recovery (11,12). All children, except the one who cried, were quiet, well oriented and coordinated, and cooperative in the recovery room, whereas 70% of patients in the thiopental/halothane group were crying, agitated, uncoordinated, and uncooperative during the first 20 min. Previous studies have demonstrated that children may need larger induction doses of propofol than adults (13,14). Purcell-Jones and James (15) showed that a dose of 2.0 mg/kg in premedicated children was not always sufficient for a smooth induction. Also, Valtonen et al. (14) were not entirely satisfied with a loading dose of 2.0-2.5 mg/kg in premedicated children. Because premedication has little effect on the smoothness of induction (16), we chose a dose of 3 mg/kg for this study. Even though atropine was the only drug used for premedication, only four children exhibited signs of anxiety and fear before induction. The incidence of pain on injection in adults has been reduced by the use of a fat emulsion as a vehicle for propofol (17). We found a 25% incidence of pain with propofol and none with thiopental. These results are similar to those of Purcell-Jones et al. (24% for propofol and 10% for thiopental) (13). The incidence of pain on injection in adults is higher when the smaller veins on the dorsum of the hand are used
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(18,19).Children had a 30% incidence of pain according to Saint-Maurice et al. (20). In their study, pain was associated with the size of the vein used, which we also noted. All five children who experienced pain on injection had a 22-gauge catheter (the smallest size used in this study). The catheter was inserted in four cases in the dorsum of the hand and in the fifth case in a small vein of the antecubital fossa. Addition of lidocaine to propofol decreases pain on injection (9,10), but the role of premedication, including use of analgesics, is not yet clear. Spontaneous movements have been reported in 14%-33%(21,22) of adults. Our observation of 75%is greater than that reported by Fahy et al. in premedicated adults (22) and Purcell-Jones et al. (33%)(13), but similar to the 65% incidence observed by PurcellJones and James (15); however, in the latter study the loading dose of propofol was small (2 mg/kg). All of these movements, however, were minor in our study, appearing a few seconds after the completion of injection and lasting no longer than 25 s. SaintMaurice et al. (20) suggest a possible inadequate anesthesia when using a loading dose of 2-2.5 mg/kg of propofol. The influence of premedication and the speed of injection on the incidence of spontaneous movements is not clear; further studies are needed to evaluate whether inadequate anesthesia and central or peripheral stimulation are involved in the genesis of spontaneous movements during induction with propofol. The number of patients with spontaneous motion is smaller (20%)in the thiopental group, as previously reported (13,14). Hiccup and laryngospasm were observed in two children receiving thiopental and in none given propofol; this tendency is also similar to published data (14). Side effects such as pain or nausea and emesis were less frequent during the first postoperative hours in the propofol group. This was also reported by McCollum and colleagues (23), who found less nausea and vomiting after induction with propofol than after induction with methohexital. Briggs and colleagues (24) suggested that propofol produces some analgesic effect, contrary to the antianalgesic effect of thiopental; it is interesting that in the present study only one child needed an analgesic postoperatively in the propofol group whereas nine children in the thiopental/halothane group needed an analgesic. In conclusion, previous studies dealing with children have stressed induction characteristics (9,15), combined use of propofol and inhaled anesthetics (13,14,20), or propofol given by bolus (10). The present study shows that continuous perfusion of propofol is a safe and more effective anesthetic technique than the usual thiopentaVhalothane combina-
tion for short-duration ENT procedures in children. The rapidity and quality of awakening after propofol is superior to that observed after thiopentall halothane administration. The incidence of spontaneous movements and pain on injection is greater with propofol than with thiopental. On the other hand, excitatory side effects such as hiccup or laryngospasm were more frequently observed in the thiopental group. Further studies are needed to find a means of reducing the pain on injection associated with propofol and to understand more completely the process of spontaneous movements associated with the use of propofol for induction in children. The authors thank James Grainger for his help in the preparation of the manuscript.
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