|40 YEARS AGO
|Year : 2014 | Volume
| Issue : 3 | Page : 434-440
Total intravenous propofol and remifentanil versus balanced anesthesia with sevoflurane and remifentanil for pediatric lower abdominal surgery
Omar M.T. Elsafti, Ahmed M.S. Hamed, Sahar M Talaat, Simon H Armanious
Department of Anesthesiology, Intensive Care, and Pain Management, Faculty of Medicine, Ain Shams University, Cairo, Egypt
|Date of Submission||05-Dec-2013|
|Date of Acceptance||13-Dec-2014|
|Date of Web Publication||27-Aug-2014|
Ahmed M.S. Hamed
Department of Anesthesiology, Intensive Care, and Pain Management, Faculty of Medicine, Ain Shams University, Cairo
Source of Support: None, Conflict of Interest: None
This study aimed to evaluate and compare the induction, the maintenance, hemodynamic responses and the recovery profile of propofol-remifentanil combination (total intravenous anesthesia) and sevoflurane-remifentanil under the Bispectral index for pediatric patients undergoing short lower abdominal surgery.
Materials and methods
Sixty ASA physical status I and II patients aged 3-10 years scheduled for elective lower abdominal procedure were assigned to receive either the propofol and remifentanil combination (group P/R = 30 patients) or sevoflurane and remifentanil (group S/R = 30 patients) under Bispectral index monitoring. In both groups, anesthesia was started with remifentanil infusion (0.5 μg/kg/min) for 2 min. In the P/R group, a bolus dose of propofol 2 mg/kg was given, and then the infusion was started (7.5 mg/kg/h) and reduced gradually to 3 mg/kg/h. In the S/R group, sevoflurane 2 vol% in 100% O 2 was added and increased gradually to 8 vol%, and then reduced to 4, 3, 2 vol%.
Induction of anesthesia was rapid in the P/R group (2.3 ± 0.7 min) compared with the S/R group (2.6 ± 1.3 min). Hypotension occurred after induction 10% in the P/R group versus 30% in the S/R group. Bradycardia was a defining feature in the P/R group only. Group P/R achieved rapid extubation in 12 min and was transferred to the postanesthesia care unit, in 17 min compared with 15 and 20 min, respectively, in the S/R group.
This study indicates that the propofol-remifentanil combination is superior to the sevoflurane-remifentanil combination, with faster induction and recovery, although both techniques are considered to be safe and effective for providing anesthesia to pediatric patients.
Keywords: Pediatric, propofol, remifentanil, sevoflurane
|How to cite this article:|
Elsafti OM, Hamed AM, Talaat SM, Armanious SH. Total intravenous propofol and remifentanil versus balanced anesthesia with sevoflurane and remifentanil for pediatric lower abdominal surgery. Ain-Shams J Anaesthesiol 2014;7:434-40
|How to cite this URL:|
Elsafti OM, Hamed AM, Talaat SM, Armanious SH. Total intravenous propofol and remifentanil versus balanced anesthesia with sevoflurane and remifentanil for pediatric lower abdominal surgery. Ain-Shams J Anaesthesiol [serial online] 2014 [cited 2021 Oct 22];7:434-40. Available from: http://www.asja.eg.net/text.asp?2014/7/3/434/139589
| Introduction|| |
As the practice of outpatient pediatric surgery advances, the search continues for an anesthesia that provides rapid recovery, adequate postoperative analgesia and avoids postoperative nausea and vomiting (PONV) . Complete awaking and orientation immediately after termination of surgery is highly desirable, thereby potentially reducing the time in the operating theatre, performing earlier release from the postanesthesia care unit (PACU), and therefore reducing staff costs .
The esterase-metabolized opioid, remifentanil hydrochloride, is considered as an ultrashort-acting opioid. It has pharmacokinetic properties that are suitable for ambulatory anesthesia and recovery. It is used in pediatrics when anesthesia needs to be induced rapidly. Because the primary narcotic effect of remifentanil ends very quickly, it allows flexible analgesia throughout the operation until the final skin stitches . The pharmacokinetics of remifentanil allows smooth emergence from anesthesia. Therefore, it may be a useful anesthetic for pediatric inpatient and outpatient surgery .
A total intravenous anesthesia (TIVA) regimen with remifentanil and propofol is a useful anesthetic technique that offers several advantages, such as controlling the response to tracheal intubation and intense surgical stimulation, which are commonly used in pediatric anesthesia .
Even though published results of studies comparing TIVA with balanced anesthesia in a large population of children and infants under the Bispectral index (BIS) are still lacking . The combination of sevoflurane/remifentanil and the combination of propofol/remifentanil have been studied previously in adults undergoing lengthy surgery (>3 h) under BIS guidance .
This study was designed to compare the induction characteristics, hemodynamic and respiratory effects and the postoperative recovery pattern of the sevoflurane-remifentanil combination versus propofol-remifentanil in children aged 3-10 years.
| Materials and methods|| |
This study was conducted at the pediatric surgery unit of Ain Shams University Hospital, after obtaining departmental approval and informed parent's consent. Sixty pediatric patients of both sexes aged 3-10 years of class I or class II of the American Society of Anesthesiologists classification were included in the study. The patients were scheduled to undergo short lower abdominal procedures such as inguinal hernia repair, hydrocele, circumcision, hypospadius repair, repair of undescended testes etc. The average duration of the procedure was to be 30-60 min.
The following patients were excluded from the study: patients having pneumonia and lung disease and those with a history of allergic or other serious adverse experience with anesthesia, congenital heart disease, metabolic and central nervous system disease and anticipated airway management problems.
After preanesthetic assessment, children were admitted to the operating theatre 60 min before the time of the scheduled surgery. EMLA cream was applied to the dorsum of both hands, and the baseline heart rate (HR) and the blood pressure were recorded. Children were randomized, using computer-generated random numbers, to receive either propofol and remifentanil (group P/R = 30 patients) or sevoflurane and remifentanil (group S/R = 30 patients).
Two 20 G cannulas were inserted for children in the P/R group, whereas a single cannula was inserted for children in the S/R group. All children were premedicated with midazolam (0.03 mg/kg) intravenously, and then an intravenous fluid of ringer lactate solution (5 ml/kg) was started. Before the induction of anesthesia, three-channel ECG, finger or ear pulse oximetry, noninvasive blood pressure and capnography (HP monitor) were connected to the patient. After induction, BIS (IntelliVue MP20 monitor; Philips) and body temperature were monitored with an esophageal temperature probe.
Administration of atropine (10 μg/kg) intravenously was performed, followed by preoxygenation using either Jackson Ree's modification of Ayre's T-piece or the Bain circuit according to the patient's weight. Thereafter, anesthesia was started with remifentanil infusion (0.5 μg/kg/min) for 2 min.
In the P/R group, a bolus dose of propofol 2 mg/kg was given (in case of insufficient effect, 2 mg/kg was added). Then, the propofol infusion was started at 7.5 mg/kg/h until skin incision, and then reduced gradually till reaching 3 mg/kg/h maintenance.
In the S/R group, sevoflurane 2 vol% in 100% O2 was added, and increased gradually till 8 vol% (cessation of spontaneous movement), and then maintained at 2-4 vol% after tracheal intubation.
After the loss of eyelash reflex, suxamethonium 1.5 mg/kg was given to facilitate endotracheal tube placement. After induction, children received a paracetamol suppository (15-25 mg/kg). Regional anesthesia technique, either caudal or nerve block, was performed before the start of the operation. Throughout the procedure, the children received 100% oxygen at 3 l FGF and remifentanil (0.25 μg/kg/h). At the end of the surgery (after skin closure), in both groups, all anesthetics were stopped. For 10 min after the discontinuation of anesthesia, no physical stimulation was performed. If the patient did not show any sign of arousal after 10 min, stimulation was allowed. Extubation was performed after achieving regular respiration with adequate tidal volume (6 ml/kg), gag reflex on oral suction, grimace and purposeful movement. Then patients were transferred to the PACU.
Signs of inadequate anesthesia in response to surgical stimulation were identified by motor, vegetative reaction or blood pressure and HR increases of greater than 20% of the identified basic values for more than 60 s. In this case, the remifentanil infusion was increased by 0.25 μg/kg/min. If anesthesia was still inadequate, the propofol infusion was increased by 2 mg/kg/h in the P/R group, whereas sevoflurane was increased by 50% in the in S/R group. Hypotension (blood pressure 20% below the baseline value) was first treated by augmenting intravascular fluid with 2.5-10 ml/kg lactated Ringer's solution, together with the reduction of propofol infusion 2 mg/kg/h in the P/R group or the decrease of sevoflurane concentration by 50%. If still persistent, the remifentanil infusion was reduced by 0.25 μg/kg/min, but not to be less than 0.125 μg/kg/min. Bradycardia (HR<100 beats/min in children<4 years, <80 beats/min in children between 4 and 8 years of age, or <60 beats/min in children>8 years) for more than 60 s, was treated by atropine 10 μg/kg intravenously.
Data collection was carried out as follows: the induction time (the time from the start of remifentanil infusion till the loss of eyelash reflex in both groups) and the intubation time (the time from the start of remifentanil infusion till successful placement of the endotracheal tube) were recorded for each patient. Also, the time from the end of anesthesia to extubation, discharge to the PACU, discharge from the recovery room and achievement of Steward score greater than 4 were recorded.
Vital signs (HR and systolic arterial blood pressure) were recorded at the following times: on arrival to the operating room, before application of each drug, on intubation, on skin incision (1, 3, 5 and 10 min), after skin incision, on stopping anesthesia and 1 and 3 min after extubation. For respiratory assessment, the average values of the following parameters were recorded throughout the operation: the respiratory rate, the tidal volume, the end tidal carbon dioxide concentration and oxygen saturation.
Awareness was monitored by recording BIS values every 5 min after the induction of anesthesia till tracheal extubation. Patients' alertness was assessed for 1 h after extubation by the Steward postanesthetic recovery score  [Table 1].
Adverse events such as PONV were monitored for up to 24 h after discharge from the PACU.
Statistical data analysis
A sample size of 60 was calculated on the basis of previous studies on the time to extubation after propofol and sevoflurane as the primary end point , with a difference of 5 min, 90% power and an α error of 0.05. To compensate for dropouts, we enrolled 30 patients in each group.
Data were collected, tabulated, coded, and then analyzed using the SPSS computer software version 12.0. First, numerical variables were examined for normality, and then were presented as the mean and SD; in contrast, categorical variables were presented as the number of cases and percent. Error bars represent 95% confidence interval. An unpaired Student t-test was used for between-group comparison of numerical variables if its assumptions were fulfilled, and otherwise, the Mann-Whitney test was used instead. The χ2-test or Fisher's exact test were used, whenever appropriate, for between-group comparisons with regard to categorical variables. A difference with P value less than 0.05 was considered to be statistically significant.
| Results|| |
There was no statistically significant difference (P > 0.05) between both groups with regard to age, sex and weight with an average age of 5.4 years; also, there were 18 patients below 6 years of age in the P/R group and 17 in the S/R group. The duration of the surgical procedure showed no statistically significant difference for both groups. With regard to the time to loss of eyelash reflex, the time to intubation and the time to skin incision, there was no statistically significant difference between both groups [Table 2].
|Table 2: Comparison between groups with respect to demographic data, the duration of surgery and times to loss of eyelash reflex, intubation and skin incision|
Click here to view
The HR in the P/R group decreased significantly with the induction of anesthesia in comparison with the basic values, and statistically significant bradycardia continued till extubation. In the P/R group, eight patients (26%) showed bradycardia immediately after induction, whereas 17 (56%) showed bradycardia at the time of skin incision. In contrast, in the S/R group, the HR showed no significant changes from induction to intubation, with significant tachycardia developing at the time of skin incision, which usually required treatment. Seventeen patients (56%) experienced tachycardia immediately after intubation, but only 12 patients (40%) remained tachycardic till extubation. Tachycardia occurred in both groups at the time of extubation. The average HR at any time was statistically lower in P/R group than in the S/R group [Table 3].
|Table 3: Comparison between group P/R and group S/R regarding the heart rate|
Click here to view
Systolic blood pressure in the P/R group showed phases of hypertension after skin incision, which was controlled by increasing the remifentanil dose. However, the systolic blood pressure value was significantly lower after induction till extubation in the S/R group. Blood pressure started to decrease with the induction of anesthesia, and remained significantly lower than the baseline values throughout the operation; however, it was elevated again at extubation. Values were significantly higher in the P/R group than in the S/R group from the intubation time till the extubation time [Table 4].
|Table 4: Comparison between group P/R and group S/R regarding the systolic blood pressure|
Click here to view
The respiratory rate and the tidal volume were significantly lower in the P/R group, whereas the end tidal carbon dioxide concentration and the oxygen saturation showed no significant difference in both groups. Breath holding, coughing and other airway problems that occur during the induction of general anesthesia in pediatrics were not frequent and showed no statistically significant difference between both groups. Bronchospasm occurred in one patient in the P/R group [Table 5].
|Table 5: Comparison between both groups regarding air problems during the induction of anesthesia and the average respiratory function characteristics in each group|
Click here to view
Values for BIS were similar between the groups during surgery. At extubation, BIS values in the P/R group were significantly higher than in the S/R group, but during the remaining time of the recovery period, these differences disappeared [Table 6].
|Table 6: Comparison between group P/R and group S/R regarding values of BIS|
Click here to view
After the end of anesthesia, patients in the P/R group showed a significantly earlier extubation than those in the S/R group (11.8 ± 4.2 and 15.0 ± 5.6 min, respectively). Also, they achieved a significantly earlier transfer from the operating room to the PACU (17.2 ± 4.6 and 20.8 ± 5.7 min, respectively) [Table 7].
|Table 7: Comparison between group P/R and group S/R regarding the time between the end of anesthesia to|
extubation, transfer to the PACU and the time to the first Steward score of 4
Click here to view
Steward postanesthesia recovery score values were significantly higher in the P/R group than in the S/R group at extubation, and 1, 3 and 5 min later. In contrast, the duration between the end of anesthesia and discharge from the recovery room showed no significant differences between both groups [Table 8].
|Table 8: Comparison between group P/R and group S/R in the progression of SPARS postoperatively|
Click here to view
| Discussion|| |
Data from this work show that TIVA with a bolus dose of propofol and remifentanil speeded children's return to consciousness and allowed rapid release from the recovery area.
The combination of sevoflurane/remifentanil and the combination of propofol/remifentanil have been studied previously in adults undergoing lengthy surgery (>3 h) under BIS guidance .
TIVA using propofol 3.5 mg/kg and remifentanil 4 μg/kg provided excellent to good conditions for tracheal intubation in children aged 3-9 years .
The present study showed that remifentanil infusion at rate of 0.5 μg/kg/min followed 2 min by either propofol 2 mg/kg or sevoflurane 2.5%, and then succinylcholine 1.5 mg/kg resulted in rapid induction with loss of eyelash reflex in 2.6 min and excellent intubation conditions at 5.8 min. Loss of eyelash reflex was 30 s earlier in the sevoflurane group, which was statistically significant, but clinically nonsignificant.
The MAC of sevoflurane has been documented to range between 2.03 and 2.5% in children aged 1-12 years .
The reduction of MAC by remifentanil infusion was proved by Domian et al.  in 2005. They found that the MAC of sevoflurane was 2.39 ± 0.58% with 0.3 μg/kg/min remifentanil, 1.91 ± 0.36% with 0.6 μg/kg/min remifentanil and 0.92 ± 0.11% with 1.2 μg/kg/min remifentanil. These findings were comparable to the present study as the average remifentanil dose in the S/R group of 0.32 ± 0.08 μg/kg/min was accompanied by a sevoflurane concentration of 2.16 ± 0.3%.
In contrast, Min et al.  used a dose of remifentanil of 0.5 μg/kg in 5% sevoflurane for successful endotracheal intubation without a muscle relaxant, in children aged 3-10 years. They used a higher sevoflurane concentration as they did not use a muscle relaxant.
The lack of any severe anesthetic induction complications in the present study may reveal the safety of both induction techniques. This has also been confirmed earlier by Hanna et al.  who found no significant difference between sevoflurane and propofol induction of general anaesthesia in pediatrics with regard to intubating conditions.
Regarding hemodynamics, children in the P/R group responded to intubation and subsequent surgical stimulation with an increase in the blood pressure, which is significantly different from the S/R group. This was successfully managed by increasing the remifentanil dose by 0.25 μg/kg/min.
This explains the possibly slightly higher consumption of remifentanil in the P/R group than in the S/R group, but fortunately, it decreased the propofol requirement . Hence, the starting dose of propofol here was 2 mg/kg.
Bradycardia and decrease in the systolic blood pressure by up to 10% from the baseline occurred during induction in the P/R group, which concurs with a study conducted by Hye et al. , wherein they found no profound hypotension or bradycardia after propofol-remifentanil induction of general anesthesia in pediatrics. They also used atropine (10 μg/kg) as a premedication.
In contrast, Sermin et al.  reported a profound decrease in HR by 31% and mean arterial pressure by 24% after propofol-remifentanil induction, despite using atropine as premedication, but they used higher doses of propofol and remifentanil than the one used here.
The hypotension in the S/R group was highly significant, reaching about 30% from the baseline after 10 min of intubation. This is in contrast to a study conducted by Ross and colleagues, who found that remifentanil-related hypotension during sevoflurane pediatric anesthesia was only 17% and it became worse with atropine, which decreased the ventricular filling. Hence, the explanation for the high incidence of hypotension is the routine use of atropine premedication .
Hypotension in the S/R group resolved spontaneously and, when persistant, it was treated by decreasing the remifentanil dose. This was also confirmed by a study conducted by Reyntjens et al. . However, Peter et al.  used fluid administration to control sevoflurane-remifentanil-related hypotension in pediatric patients.
The HR in the S/R group increased in response to intubation, skin incision and extubation, but its peak was 127 beats/min at the time of extubation, which is different from Peter's study as the peak HR was 117 beats/min as they did not use atropine premedication .
For all children in both groups, the HR throughout the anesthesia maintenance phase never exceeded 30% above the preoperative baseline value due to adequate blocking of autonomic response by remifentanil.
The respiratory rate and the tidal volume (ventilatory function) were significantly lower in the P/R group compared with the S/R group, but this does not significantly affect the end tidal carbon dioxide concentration and oxygen saturation, which was almost similar in the two groups. Christine et al.  compared sevoflurane and propofol regarding ventilation affection, and they also concluded that propofol was associated with a significant decrease in the respiratory rate and the tidal volume.
Tsui et al.  used the remifentanil-propofol combination for children undergoing MRI examination. They found that there was a significant decrease in the respiratory rate, and it was associated with an increase in the end tidal CO2, which contradicts the results of the present study. This may be attributed to a lack of surgical stimulation in their study.
In the present study, there was no correlation between respiratory depression and the remifentanil dose in the range of 0.125-0.5 μg/kg/min, although it was found by Hayes et al.  that remifentanil at a dose of 0.5-1.5 μg/kg/min was associated with a more increased incidence of respiratory depression.
Davidson et al.  determined that the incidence of intraoperative awareness in children in the age group of 5-12 years was about 0.8%. This is four- to eight-fold that reported for adults (0.1%). In the present study, the application of BIS monitoring was aimed to increase safety and avoid using excess doses of the anesthetic agent. The predefined BIS target of 35-45 during anesthesia was accomplished, with values lying between 30 and 48 throughout operation.
Interestingly, propofol, sevoflurane and remifentanil were used at the lower limit of their clinical dosage range. In previous studies without depth of anesthesia monitoring, Domian et al.  used remifentanil 0.3 μg/kg/min with sevoflurane 2.39%, whereas in the present study, remifentanil 0.32 μg/kg/min with sevoflurane 2.1% was used successfully. In contrast, Ganidagli et al.  used a propofol dose of 6 mg/kg/h for the maintenance of remifentanil-based anesthesia in children, whereas only 4.5 mg/kg/h was used here.
Recovery (extubation and transfer to the recovery room) was significantly earlier in the P/R group (12 min) than in the S/R (15 min) group. Although the difference was 2-4 min, this does not offer a relevant clinical advantage. This concurs with the study conducted by Picard et al.  in 2001, who investigated the recovery characteristics after tonsillectomy using either propofol or sevoflurane, and the extubation time was 14-15 min.
Also, Hocker et al.  in 2006 confirmed that even for long-lasting operations with an average time of 3.5 h, the extubation time after propofol/remifentanil versus sevoflurane/remifentanil was 8.3 versus 10.4 min, respectively.
In the present study, earlier return of awareness was significantly achieved in the P/R group. Children in this group achieved Steward score greater than 4 after 13 versus 21 min in the S/R group.
PONV was a frequent postoperative complication in the present study reaching about 20% in both study groups, with no significant difference between the two groups. This is concomitant with the study conducted by Hocker et al. , who stated that the incidence of PONV showed no significant difference between the propofol-remifentanil group versus the sevoflurane-remifentanil group in adults.
This study indicates that the propofol-remifentanil combination is superior to the sevoflurane-remifentanil combination in pediatric anesthesia, with faster induction and recovery, although both techniques are considered to be safe and effective.
| Acknowledgements|| |
| References|| |
|1.||Ingrid H. Current trend in pediatric anesthesia. Mt Sinai J Med 2002; 69:51-54. |
|2.|| Joachim B, Norbert J, Bernhard K, et al. Economic considerations of the use of new anesthetics: a comparison of propofol, sevoflurane and isoflurane. Anesth Analg 1999; 86:504-509. |
|3.|| Leopoldo MS, Leandro GB, Norma SP. Emergence agitation in pediatric current features. J Pediatr 2008; 84:107-113. |
|4.|| Peacock JK, Philip BK. Ambulatory anesthesia experience with remifentanil. Anesth Analg 1999; 89:22-27. |
|5.|| Torsten L, Hans-Joachim P. Recovery after anesthesia with remifentanil combined with propofol, desflurane or sevoflurane for otorhinolaryngeal surgery. Anesth Analg 2000; 91:123-129. |
|6.|| Serven A, Joachim S, Brigit F, et al. Total intravenous anesthesia using propofol remifentanil compared to balanced anesthesia using sevoflurane and remifentanil in ambulatory and inpatient pediatric surgery. Anaesthesiology 2003; 99:A1379. |
|7.|| Hocker J, Tonner PH, Bollert P. Propofol/remifentanil vs sevoflurane/remifentanil for long lasting surgical procedures: a randomized controlled trial. Anaesthesia 2006; 61:752-757. |
|8.|| Steward DJ. A simplified scoring system for the post-operative recovery room. Can Anaesth Soc J 1975; 22:111-113. |
|9.|| Larsen B, Seitz A, Larsen R. Recovery of cognitive function after remifentanil-propofol anesthesia: a comparison with desflurane and sevoflurane anesthesia. Anesth Analg 2000; 90:168-174. |
|10.||Ulla MK, Arja H. Tracheal intubation after induction of anesthesia in children with propofol-remifentanil or propofol-rocuronium. Can J Anaesth 2000; 47:854-859. |
|11.||Smith I, Nathanson MH, White PF. Sevoflurane-a long awaited volatile anaesthetic. Br J Anesth 1996; 76:435-445. |
|12.||Domain JC, William MS, Natalie AC. Remifentanil decreases sevoflurane requirements in children. Can J Anaesth 2005; 52:1064-1070. |
|13.||Min SK, Kwak YL, Park SY, et al. The optimal dose of remifentanil for intubation during sevoflurane induction without neuromuscular blockade in children. Anaesthesia 2007; 62:446-450. |
|14.||Hanna V, Pekka T, Susanna M, et al. Sevoflurane maintained anesthesia induced with propofol or sevoflurane in small children: induction and recovery character. Can J Anaesth 1999; 46:21-28. |
|15.||Jayabose S, Levendoglu TO, Giamelli J, et al. Intravenous anesthesia with propofol for painful procedures in children with cancer. J Pediatr Hematol Oncol 2001; 23:290-293. |
|16.||Hye JP, Jeong RL, Chong SK, et al. Remifentanil halves the EC50 of propofol for successful insertion of the laryngeal mask airway and laryngeal tube in pediatric patients. Anesth Analg 2007; 105:57-61. |
|17.||Sermin O, Hasan H, Hakan K, et al. Low doses of rocronium during remifentanil-propofol-based anesthesia in children: comparison of intubating condition. Paediatr Anesth 2004; 14:636-641. |
|18.||Ross AK, Davis PJ, Dear GL, et al. Pharmacokinetics of remifentanil in anesthesized pediatric patients undergoing elective surgery or diagnostic procedures. Anesth Analg 2001; 93:1393-1401. |
|19.||Reyntjens K, Foubert L, Wolf DD, et al. Glycopyrrolate during sevoflurane-remifentanil-based anaesthesia for cardiac catheterization of children with congenital heart disease. Br J Anaesth 2005; 95:680-684. |
|20.||Peter JD, Julia CF, Rosemary JI, et al. A randomized, double-blinded study of remifentanil versus fentanyl for tonsillectomy and adenoidectomy surgery in pediatric ambulatory surgical patients. Anesth Analg 2000; 90:863-871. |
|21.||Christine O, Britta S, Von Ungen S, et al. Respiratory reflex responses of the larynx differ between sevoflurane and propofol in pediatric patients. Anesthesiology 2005; 103:1142-1148. |
|22.||Tsui BC, Wagner A, Usher AG, et al. Combined propofol and remifentanil intravenous anesthesia for pediatric patients undergoing magnetic resonance imaging. Paediatr Anaesth 2005; 15:397-401. |
|23.||Hayes JA, Lopez AV, Pehora CM. Coadministration of propofol and remifentanil for lumbar puncture in children: dose-response and evaluation of two dose combination. Anesthesiology 2008; 109:613-618. |
|24.||Davidson AJ, Huang GH, Czarnecki C, et al. Awareness during anesthesia in children: a prospective cohort study. Anesth Analg 2005; 100:653-661. |
|25.||Ganidagli S, Cengiz M, Baysal Z. Remifentanil vs alfentanil in the total intravenous anesthesia for paediatric abdominal surgery. Paediatr Anaesth 2003; 13:695-700. |
|26.||Picard V, Dumont L, Pellegrini M. Quality of recovery in children: sevoflurane versus propofol. Acta Anaesthesiol Scand 2001; 44:307-310. |
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6], [Table 7], [Table 8]