Low-dose intramuscular ketamine for anesthesia pre-induction in young children undergoing brief outpatient procedures

The authors sought to determine whether intramuscular ketamine (2 mg/kg) would facilitate inhaled induction of anesthesia in those children who are uncooperative. Thirty-five children were anesthetized with halothane and nitrous oxide for insertion of tympanotomy tubes. Twenty of those children were deemed by the anesthesiologist to be uncooperative and received 2 mg/kg of ketamine im prior to induction of anesthesia. The onset time (time from ketamine administration until induction of inhaled anesthesia could be started) was 2.7 +/- 0.3 min. The quality of the subsequent acceptance of inhaled induction with halothane was excellent in 61% of the patients and adequate in the remaining 39%. The recovery and discharge times were compared with those observed in 15 matched children who accepted induction of anesthesia via a mask without the use of ketamine. Recovery time was not prolonged, but home discharge was delayed by an average of 13 min in the ketamine group (P less than 0.04). Low-dose im ketamine was found to be an acceptable pre-induction drug in young children who are uncooperative for an inhaled induction of anesthesia.     

A comparison of two different doses of ketamine with midazolam and midazolam alone as oral preanaesthetic medication on recovery after sevoflurane anaesthesia in children

BACKGROUND: This investigation prospectively evaluated the effect of oral premedication of two different doses of ketamine with midazolam and midazolam alone on the recovery of children after sevoflurane anaesthesia. METHODS: In a randomized, double-blind study, 79 children (aged 1-8 years, ASA physical status I or II) were assigned to receive one of three premedications in a volume of 0.5 ml x kg(-1): group 1 received midazolam 0.5 mg x kg(-1) (MD); group 2 received midazolam 0.5 mg x kg(-1) with ketamine 1.8 mg x kg(-1) (MK-1); and group 3 received midazolam 0.5 mg x kg(-1) with ketamine 3 mg x kg(-1) (MK-2). The reactions of the children during administration were noted. Anaesthesia was induced by facemask with incremental sevoflurane administration. All children received alfentanil (15 micro g x kg(-1)). Tracheal intubation was facilitated by mivacurium (0.2 mg x kg(-1)). Anaesthesia was maintained with sevoflurane and an additional dose of alfentanil, if necessary. During recovery, the time interval between discontinuation of anaesthesia and arousal (spontaneous ventilation, extubation) were recorded. RESULTS: Emergence (spontaneous ventilation, extubation) and recovery times (discharge, Aldrete score=9) did not differ significantly between groups (P=0.24, P=0.59 and P=0.145, respectively). CONCLUSIONS: The combination of midazolam and ketamine as oral preanaesthetic medication did not significantly affect the recovery time of children after sevoflurane anaesthesia.     

Adverse events and behavioral reactions related to ketamine based anesthesia for anorectal manometry in children

BACKGROUND: Pediatric patients undergoing anorectal manometry require ketamine anesthesia as other anesthetic agents affect the anorectal sphincter tone. The aim of this prospective observational audit was to evaluate our practice and report the occurrence of adverse events and behavioral reactions related to the use of ketamine, propofol, and midazolam combinations. METHODS: Eighty-two consecutive pediatric patients (mean age 8.06 +/- 3.43 years) undergoing anorectal manometry were audited over a 1-year period. After a routine ketamine anesthetic some children were administered midazolam 0.1 mg.kg(-1), at the discretion of the attending anesthetist. Children requiring anal stretch following manometry studies also received propofol 3-5 mg.kg(-1). Intra- and postoperative adverse events, times to spontaneous awakening and discharge from the PACU were noted. Postoperative behavioral reactions were noted in the PACU and at follow-up interviews on the first postoperative day and after a period of 1 month. RESULTS: Following completion of the audit, all patients fell into one of the four groups depending on the anesthetic agents they received: K (ketamine only, n = 16), KM (ketamine and midazolam, n = 10), KP (ketamine and propofol, n = 27), and KPM (ketamine, propofol, and midazolam, n = 29). There was no difference in the occurrence of behavioral reactions between the four groups at the three stages of follow-up. Overall, five patients reported 'new onset' nightmares that had resolved completely at the 3-month follow-up. The time to spontaneous awakening was shorter for K group (17.8 min +/- 20.2) vs KPM group (61.7 min +/- 24.4; P < 0.001). The times to discharge in minutes was also shorter in the K group (54.5 min, IQR 30-75 vs 90 min IQR 78-120; P < 0.001). Administration of propofol appeared to have an antiemetic effect [odds ratio (OR) 0.1, 95% confidence intervals (CI) 0.02-0.58, P < 0.009] in the recovery unit. CONCLUSIONS: Our study findings suggest that, besides significantly prolonging time to spontaneous awakening and PACU discharge, neither the use of midazolam, propofol, or combinations is beneficial in preventing the occurrence of behavioral reactions following ketamine anesthesia. Behavioral reactions were common but did not appear to be long-term. Drug combinations with ketamine may have other benefits such as antiemesis.     

Vomiting and Recovery after Outpatient Tonsillectomy and Adenoidectomy in Children: Comparison of Four Anesthetic Techniques Using Nitrous Oxide with Halothane or Propofol

Background: The authors' purpose in this study was to compare prospectively four different anesthetic induction and maintenance techniques using nitrous oxide with halothane and/or propofol for vomiting and recovery after outpatient tonsillectomy and adenoidectomy procedures in children.

Methods: Eighty unpremedicated children, aged 3-10 yr, were assigned randomly to four groups: group H/H, 0.5-2% halothane induction/halothane maintenance; group P/P, 3-5 mg *symbol* kg sup -1 propofol induction and 0.1-0.3 mg *symbol* kg sup -1 *symbol* min sup -1 propofol maintenance; group H/P, 0.1-0.3 mg *symbol* kg sup -1 *symbol* min sup -1 halothane induction/propofol maintenance; and group P/H, 3-5 mg *symbol* kg sup -1 propofol induction and 0.5-2% halothane maintenance. Nitrous oxide (67%) and oxygen (33%) were administered in all the groups. Other treatments and procedures were standardized intra- and postoperatively. Results of postoperative vomiting and recovery were analyzed in the first 6 h and beyond 6 h.

Results: Logistic regression showed that vomiting occurred 3.5 times as often when halothane was used for maintenance of anesthesia (groups H/H and P/H) compared with the use of propofol (groups P/P and H/P; Odds Ratio 3.5; 95% confidence interval 1.3 and 9.4, respectively; P = 0.012). A significant association between vomiting (< 6 h: yes/no) and discharge times (> 6 h: yes/no) (Odd's Ratio = 3.6; 95% confidence interval: 1.02, 12.4, respectively) (P = 0.046) was shown. However, no significant differences among the groups in the incidence of vomiting beyond 6 h, recurrent vomiting, or hospital discharge times were shown.     

Propofol as a sole agent for paediatric day care diagnostic ophthalmic procedures: comparison with halothane anaesthesia

BACKGROUND: Our aim was to study the feasibility of total intravenous anaesthesia with propofol in spontaneously breathing children undergoing ophthalmic procedures. METHODS: Fifty-five children (aged 6 months to 5 years) were randomly allocated to receive either propofol bolus (until loss of eyelash reflex) followed by infusion [group P (n=29)] or halothane 3-4% for induction, followed by 1-2% in 70% nitrous oxide and oxygen via face mask [group H (n=28)]. Dose for induction and maintenance, intraoperative adverse events, time to recovery (on an Observer's Assessment of Alertness/Sedation Scale, 5 at each level) and duration of procedure were recorded. All children in both groups, were anaesthetized successfully. RESULTS: 4.0 +/- 0.7 mg x kg(-1) and 5.1 +/- 1.0 mg x kg(-1) of propofol were required for loss of eyelash reflex and tolerance of the ophthalmic speculum, respectively. An infusion rate of 8.3 +/- 1.7 mg x kg(-1) x h(-1) was needed for maintenance of anaesthesia; 3.4 +/- 0.5%, 3.6 +/- 0.4% and 1.4 +/- 0.4% halothane was needed for induction, tolerance of the eye speculum and maintenance of anaesthesia, respectively. Induction and recovery were significantly faster with halothane compared with propofol [induction - 38.3 +/- 6.6 s (group H)/60.9 +/- 15.2 s (group P) (P < 0.001); recovery 12.8 +/- 4.6 min (group H)/27.0 +/- 23.3 min (group P) (P < 0.001)]. Apnoea, coughing and breath-holding were seen only in group H. Group P had significantly higher incidence of involuntary movements (minor degree) (n=6) (P < 0.01). CONCLUSIONS: Propofol is a feasible option for paediatric diagnostic ophthalmic procedures with the advantage over halothane of providing complete access to the eye.     

Reevaluation of rectal ketamine premedication in children: comparison with rectal midazolam

BACKGROUND: Results of previous studies of rectal ketamine as a pediatric premedication are clouded because of lack of dose-response relation, inappropriate time of assessing sedative effects, and previous administration or coadministration of benzodiazepines. Therefore, the authors reevaluated the efficacy of rectally administered ketamine in comparison with 1 mg/kg rectal midazolam. METHODS: Sixty-six infants and children (age, 7-61 months) who were American Society of Anesthesiologists physical status I and who were undergoing minor surgeries as in-patients were randomized to receive 5 mg/kg ketamine (n = 16), 7 mg/kg ketamine (n = 16), 10 mg/kg ketamine (n = 17), or 1 mg/kg midazolam (n = 17) via rectum. A blinded observer scored sedation 45 min and 15 min after administration of ketamine and midazolam, respectively, when children were separated from parent(s) for inhalational induction. All children underwent standardized general anesthesia with sevoflurane, nitrous oxide, and oxygen with endotracheal intubation. Blood pressure, heart rate, and oxyhemoglobin saturation were determined before, during, and after anesthesia. Postoperative recovery characteristics and incidence of adverse reactions were also assessed. RESULTS: Most children (88%) who received rectally 10 mg/kg ketamine or 1 mg/kg midazolam separated easily from their parents compared with those (31%) who received 7 or 5 mg/kg rectal ketamine (P < 0.05). Similarly, more children who received 10 mg/kg ketamine or 1 mg/kg midazolam underwent mask induction without struggling or crying compared with those who received 7 or 5 mg/kg ketamine (P < 0.05). There were no clinically significant changes in blood pressure, heart rate, and oxyhemoglobin saturation after administration of either drug. Immediately after surgery, more children receiving midazolam or 5 mg/kg ketamine were agitated compared with 7 or 10 mg/kg ketamine. Ketamine, 7 and 10 mg/kg, provided postoperative analgesia, but the largest dose of ketamine was associated with delayed emergence from general anesthesia. CONCLUSIONS: The results indicate that rectally administered ketamine alone produces dose-dependent sedative effects in children, when evaluated at its predicted peak plasma concentration. Ketamine, 10 mg/kg, has a delayed onset but is as effective as 1 mg/kg midazolam for sedating healthy children before general anesthesia. However, 10 mg/kg rectal ketamine is not recommended for brief surgeries because of prolonged postoperative sedation.     

Reevaluation of Rectal Ketamine Premedication in Children: Comparison with Rectal Midazolam

Background: Results of previous studies of rectal ketamine as a pediatric premedication are clouded because of lack of dose-response relation, inappropriate time of assessing sedative effects, and previous administration or coadministration of benzodiazepines. Therefore, the authors reevaluated the efficacy of rectally administered ketamine in comparison with 1 mg/kg rectal midazolam.

Methods: Sixty-six infants and children (age, 7-61 months) who were American Society of Anesthesiologists physical status I and who were undergoing minor surgeries as in-patients were randomized to receive 5 mg/kg ketamine (n = 16), 7 mg/kg ketamine (n = 16), 10 mg/kg ketamine (n = 17), or 1 mg/kg midazolam (n = 17) via rectum. A blinded observer scored sedation 45 min and 15 min after administration of ketamine and midazolam, respectively, when children were separated from parent(s) for inhalational induction. All children underwent standardized general anesthesia with sevoflurane, nitrous oxide, and oxygen with endotracheal intubation. Blood pressure, heart rate, and oxyhemoglobin saturation were determined before, during, and after anesthesia. Postoperative recovery characteristics and incidence of adverse reactions were also assessed.

Results: Most children (88%) who received rectally 10 mg/kg ketamine or 1 mg/kg midazolam separated easily from their parents compared with those (31%) who received 7 or 5 mg/kg rectal ketamine (P < 0.05). Similarly, more children who received 10 mg/kg ketamine or 1 mg/kg midazolam underwent mask induction without struggling or crying compared with those who received 7 or 5 mg/kg ketamine (P < 0.05). There were no clinically significant changes in blood pressure, heart rate, and oxyhemoglobin saturation after administration of either drug. Immediately after surgery, more children receiving midazolam or 5 mg/kg ketamine were agitated compared with 7 or 10 mg/kg ketamine. Ketamine, 7 and 10 mg/kg, provided postoperative analgesia, but the largest dose of ketamine was associated with delayed emergence from general anesthesia.     

Midazolam premedication delays recovery from propofol-induced sevoflurane anesthesia in children 1–3 yr

PURPOSE: To study the effect of midazolam premedication on the recovery characteristics of sevoflurane anesthesia induced with propofol in pediatric outpatients. METHODS: Sixty children, one to three years, presenting for ambulatory adenoidectomy were randomly assigned , in a double-blind fashion, to receive either 0.5 mg x kg(-1) midazolam (Group M) or placebo (Group P) p.o. 30 min before anesthesia. Anesthesia was induced with 10 microg x kg(-1) atropine, 10 microg x kg(-1) alfentanil, and 3-4 mg x kg(-1) propofol i.v.. Tracheal intubation was facilitated with 0.2 mg x kg(-1) mivacurium. Anesthesia was maintained with nitrous oxide/oxygen (FiO2 0.3) and sevoflurane with controlled ventilation. Recovery characteristics were compared using the modified Aldrete scoring system, the Pain/Discomfort scale and measuring specific recovery end-points (emergence, full Aldrete score, discharge). A postoperative questionnaire was used to evaluate the children's well-being at home until 24 hr after discharge. RESULTS: Emergence from anesthesia (22 +/- 9 vs 16 +/- 6 min (mean +/- SD), P = 0.005) and achieving full Aldrete scores (30 +/- 11 vs 24 +/- 16 min, P = 0.006) were delayed in patients receiving midazolam. Children in the placebo group were given postoperative analgesia sooner than those in the midazolam group (18 +/- 11 vs 23 +/- 8 min, P = 0.009). More children premedicated with midazolam suffered from arousal distress (20% vs 3%, P = 0.04) and scored higher on the Pain/Discomfort scale (P = 0.004) at 20 min after arrival in the recovery room. Discharge was not affected by premedication and well-being at home was similar in the groups. CONCLUSIONS: Oral premedication with midazolam delays early recovery but not discharge after ambulatory sevoflurane anesthesia induced with propofol in children one to three years. Midazolam did not improve the quality of recovery.     

Oral ketamine or midazolam or low dose combination for premedication in children

This randomized controlled trial was designed to evaluate whether the combination of low dose oral midazolam (0.25 mg/kg) and low dose oral ketamine (3 mg/kg) provides better premedication than oral midazolam (0.5 mg/kg) or oral ketamine (6 mg/kg). Seventy-eight children of ASA physical status I or II scheduled for elective ophthalmic surgery were randomly divided into three groups and given premedication in the holding area 30 minutes before surgery. Two subjects from each group vomited the medication and were excluded, leaving 72 subjects for further analysis. The onset of sedation was earlier in the combination group than the other two groups. At 10 minutes after premedication 12.5% in the combination group had an acceptable sedation score compared with none in the other two groups. After 20 minutes 54% in the combination group had an acceptable sedation score, 21% in the midazolam group and 16% in the ketamine group (P<0.05). There were no significant differences in the parental separation score, response to induction and emergence score. The mean time for best parental separation score was significantly less in the combination group (19+/-8 min) than either the midazolam (28+/-7) or ketamine (29+/-7 min) groups (P<0.05). Recovery was earlier in the combination group, as the time required to reach a modified Aldrete score of 10 was significantly less in the combination group (22+/-5 min) than in the oral midazolam (36+/-11 min) or ketamine (38+/-8 min) groups. The incidence of excessive salivation was significantly higher in the ketamine alone group (P<0.05). In conclusion, the combination of oral ketamine (3 mg/kg) and midazolam (0.25 mg/kg) has minimal side effects and gives a faster onset and more rapid recovery than ketamine 6 mg/kg or midazolam 0.5 mg/kg for premedication in children.     

Premedication with midazolam delays recovery after ambulatory sevoflurane anesthesia in children.

We studied the effect of oral premedication with midazolam on the recovery characteristics of sevoflurane anesthesia in small children. In a randomized, double-blinded study, 60 children (1-3 yr, ASA physical status I or II) undergoing ambulatory adenoidectomy received either midazolam 0.5 mg/kg (Group M) or placebo (Group P) PO approximately 30 min before the induction of anesthesia. All children received atropine 0.01 mg/kg IV and alfentanil 10 microg/kg IV before the induction of anesthesia with sevoflurane up to 8 vol% inspired concentration in N2O 67% in O2. Tracheal intubation was facilitated with mivacurium 0.2 mg/kg. Anesthesia was continued with sevoflurane adjusted to maintain hemodynamic stability. In the postanesthesia care unit, predetermined recovery end points (emergence, recovery, discharge) were recorded. A pain/ discomfort scale was used to determine the quality of recovery. A postoperative questionnaire was used to evaluate the well-being of the patient at home 24 h after surgery. Emergence (spontaneous eye opening), recovery (full points on the modified Aldrete scale), and discharge were achieved later in Group M than in Group P (15+/-6 vs. 11+/-3 min [P = 0.002], 25+/-17 vs. 16+/-6 min [P = 0.01], and 80+/-23 vs. 70+/-23 min [P = 0.03]). Side effects, postanesthetic excitement, and analgesic treatment did not differ significantly between groups. At home, more children in Group P (30%) experienced disturbed sleep during the night compared with those in Group M (4%) (P = 0.007). IMPLICATIONS: In this randomized, double-blinded, placebo-controlled study, premedication with midazolam 0.5 mg/kg PO delayed recovery in children 1-3 yr of age after brief (<30 min) sevoflurane anesthesia. Except for more peaceful sleep at home, premedication did not affect the quality of recovery.     

Changes in the auditory evoked potentials index by induction doses of four different intravenous anesthetics

BACKGROUND: Many studies have investigated the electroencephalographic changes during the induction and maintenance of anesthesia. However, no comparative studies have been performed on the effects of intravenous anesthetics on the auditory evoked potentials index (AAI). The present study was performed to compare the changes in AAI caused by induction doses of thiopental, propofol, midazolam and ketamine. METHODS: Eighty females, aged 30-70 years, referred for mastectomy, had anesthesia induced with thiopental 4 mg/kg, propofol 2 mg/kg, midazolam 0.1 mg/kg or ketamine 1 mg/kg (each 20 patients). The response to verbal command and the AAI were measured every minute for 5 min. RESULTS: The AAI decreased to less than 40 within 1 min with thiopental and propofol. The AAI increased after 3 min with thiopental, but remained low with propofol. The AAI gradually decreased to less than 40 within 4 min with midazolam, but was higher than the AAI with propofol or thiopental. The AAI increased significantly with ketamine. The AAIs at the loss of verbal command were 19 +/- 7 with thiopental, 21 +/- 8 with propofol, 31 +/- 10 with midazolam and 92 +/- 2 with ketamine. CONCLUSION: The AAI correlated with changes in hypnotic level, as measured by the response to verbal command, with induction doses of thiopental, propofol and midazolam, but not with ketamine. The AAI decreased to lower levels with propofol and thiopental than with midazolam at the induction of anesthesia.     

The benefits of intraoperative small-dose ketamine on postoperative pain after anterior cruciate ligament repair

In a randomized, double-blinded study with three parallel groups, we assessed the analgesic effect of intraoperative ketamine administration in 45 ASA physical status I or II patients undergoing elective arthroscopic anterior ligament repair under general anesthesia. The patients received either IV ketamine 0.15 mg/kg after the induction of anesthesia and before surgical incision and normal saline at the end of surgery (PRE group); normal saline after the induction of anesthesia and before surgical incision and IV ketamine at the end of surgery (POST group); or normal saline at the beginning and the end of surgery (CONT group). Anesthesia was performed with propofol (2 mg/kg for induction, 60-200 microg x kg(-1) x min(-1) for maintenance), sufentanil (0.2 microg/kg 10 min after surgical incision, followed by an infusion of 0.25 microg x kg(-1) x h(-1) stopped 30 min before skinclosure), vecuronium (0.1 mg/kg), and 60% N2O in O2 via a laryngeal mask airway. Postoperative analgesia was initially provided with IV morphine in the postanesthesia care unit, then with IV patient-controlled analgesia started before discharge from the postanesthesia care unit. Pain scores, morphine consumption, side effects, and degree of knee flexion were recorded over 48 h and during the first and second physiotherapy periods, performed on Days 1 and 2. Patients in the ketamine groups required significantly less morphine than those in the CONT group over 48 h postoperatively (CONT group 67.7+/-38.3 mg versus PRE group 34.3+/-23.2 mg and POST group 29.5+/-21.5 mg; P < 0.01). Better first knee flexion (CONT group 35+/-10 degrees versus PRE group 46+/-12 degrees and POST group 47+/-13 degrees; P < 0.05) and lower morphine consumption (CONT group 3.8+/-1.7 mg versus PRE group 1.2+/-0.4 mg and POST group 1.4+/-0.4 mg; P < 0.05) were noted at first knee mobilization. No differences were seen between the PRE and POST groups, except for an increase in morphine demand in the PRE versus the POST group (P < 0.05) in the second hour postoperatively. IMPLICATIONS: We found that intraoperative small-dose ketamine reduced postoperative morphine requirements and improved mobilization 24 h after arthroscopic anterior ligament repair. No differences were observed in the timing of administration. Intraoperative small-dose ketamine may therefore be a useful adjuvant to perioperative analgesic management.     

Oral midazolam in children: effect of time and adjunctive therapy.

The purpose of this study was to determine the influence of timing and concomitant administration of atropine and/or meperidine on the perioperative effects of oral midazolam in children. In 154 healthy children, 1-8 yr old, we studied six oral preanesthetic medication regimens according to a randomized, double-blind protocol. Group A (placebo) received 5 mL of apple juice. The other five groups received medication with apple juice to a total volume of 5 mL, 20-60 min before induction of anesthesia. Group B received atropine (0.02 mg/kg); group C received midazolam (0.5 mg/kg); group D received midazolam (0.5 mg/kg) and atropine (0.02 mg/kg); group E received meperidine (1.5 mg/kg) and atropine (0.02 mg/kg); and group F received meperidine (1.5 mg/kg), atropine (0.02 mg/kg), and midazolam (0.5 mg/kg). The sedative effect of midazolam was maximal 30 min after oral administration. Ninety-five percent of the children who were separated from their parents within 45 min after oral midazolam administration (with or without atropine) had satisfactory separation scores (vs 66% of those separated after 45 min; P less than 0.02). Midazolam-treated patients were more cooperative with a mask induction of anesthesia compared with non-midazolam-treated children (83% vs 56%). Neither atropine nor meperidine appeared to significantly improve the effectiveness of oral midazolam. No preoperative changes in heart rate, respiratory rate, or hemoglobin oxygen saturation were noted in any of the treatment groups. Finally, oral midazolam did not prolong recovery even after outpatient procedures lasting less than 30 min. In conclusion, midazolam (0.5 mg/kg) given orally 30-45 min before induction of anesthesia is safe and effective without delaying recovery after ambulatory surgery.     

Anaesthesia with midazolam and S-(+)-ketamine in spontaneously breathing paediatric patients during magnetic resonance imaging

We evaluated safety and efficacy of a sedation technique based on rectal and intravenous S-(+)-ketamine and midazolam to achieve immobilization during Magnetic Resonance Imaging (MRI). Thirty-four paediatric patients were randomly assigned to undergo either the sedation protocol (study group) or general anaesthesia (control group). Imaging was successfully completed in all children. Children in the study group received a rectal bolus (0.5 mg x kg(-1) midazolam and 5 mg x kg(-1) S-(+)-ketamine) and required additional i.v. supplementation (20+/-10 microg x kg(-1) x min(-1) S-(+)-ketamine and 4+/-2 microg x kg(-1) x min(-1) midazolam), spontaneous ventilation was maintained. Transient desaturation occurred once during sedation and four times in the control group (P=0.34). PECO2 was 5.3+/-0.5 kPa (40+/-4 mm Hg) in the study group and 4.1+/-0.6 kPa (31+/-5 mm Hg) in the control group (P<0.001). Induction and discharge times were shorter in the study group (P<0.001), recovery times did not differ significantly between the groups. Our study confirms that a combination of rectal and supplemental intravenous S-(+)-ketamine plus midazolam is a safe and useful alternative to general anaesthesia for MRI in selected paediatric patients.     

Midazolam reduces the dose of propofol required for induction of anaesthesia and laryngeal mask airway insertion

BACKGROUND AND OBJECTIVE: Insertion of the laryngeal mask airway in the anaesthetized patient can sometimes be difficult and propofol has been advocated as the anaesthetic induction agent of choice because of its depressant effect on laryngeal reflexes compared with other intravenous anaesthetics. However, when used as the sole induction agent, relatively large doses of propofol are required to achieve successful laryngeal mask insertion. This has cost implications and may produce unwanted cardiorespiratory depression. METHODS: One hundred and forty-two patients were randomized to receive either: fentanyl 1 microg kg(-1) and lidocaine 1.5 mg kg(-1) (group 1), or fentanyl 1 microg kg(-1) and midazolam 0.04 mg kg(-1) (group 2), or fentanyl 1 microg kg(-1), midazolam 0.04 mg kg(-1) and lidocaine 1.5 mg kg(-1) (group 3) or fentanyl 1 microg kg(-1) (group 4) 2 min before induction of anaesthesia. Anaesthesia was established with propofol infused at 33.3 mg min(-1). RESULTS: Patients who were given midazolam required significantly less propofol to achieve satisfactory laryngeal mask insertion, median propofol doses: group 1, 1.63 mg kg(-1); group 2, 1.16 mg kg(-1); group 3, 1.01 mg kg(-1); group 4, 1.9 mg kg(-1), P < 0.0001 (analysis of variance). Patients given midazolam reported less pain on injection with propofol 13% and 3% groups (2 and 3) compared with 37.5% and 77% (groups 1 and 4) P = 0.002 (chi(2)). CONCLUSIONS: Midazolam reduces the dose of propofol required for induction of anaesthesia and successful insertion of the laryngeal mask airway. There was no clinical benefit to be gained from the addition of lidocaine.     

Comparative evaluation of midazolam and ketamine with midazolam alone as oral premedication

BACKGROUND: Oral premedication with midazolam and ketamine is widely used in pediatric anesthesia to reduce emotional trauma and ensure smooth induction. However, various dosing regimens when used alone or in combination have variable efficacy and side effect profile. The aim of our study was to investigate and compare the efficacy of oral midazolam alone with a low-dose combination of oral midazolam and ketamine. METHODS: We performed a prospective randomized double-blind study in 100 children who were randomly allocated into two groups. Group M received 0.5 mg.kg(-1) oral midazolam and group MK received 0.25 mg.kg(-1) oral midazolam with 2.5 mg.kg(-1) oral ketamine. The preoperative sedation score, ease of parental separation and ease of mask acceptance were evaluated on a 4-point scale. The time to recovery from anesthesia and to achieve satisfactory Aldrete score was also noted. RESULTS: Uniform and acceptable sedation scores were seen in both the groups (group M 95.9%; group MK 97.96%), without any serious side effects. However, the combination offered significantly more children in an awake, calm and quiet state, who were easily separated from their parents (73.46% in MK vs 41% in group M). The induction scores were comparable between the groups. The recovery room characteristics and time to achieve satisfactory Aldrete score were also comparable between the two groups. CONCLUSIONS: Oral midazolam alone and a combination of midazolam with ketamine provide equally effective anxiolysis and separation characteristics. However, the combination provided more children in an awake, calm and quiet state who could be separated easily from parents.     

Comparison of the safety and efficacy of intranasal midazolam or sufentanil for preinduction of anesthesia in pediatric patients.

Nasal administration of sufentanil or midazolam is effective for preinduction of pediatric patients, but there are no data on which to base a choice between them. This blinded randomized study compares behavioral and physiologic responses to sedation with one of these medications followed by inhalation or intravenous induction. Ninety-five patients aged 0.5-10 yr scheduled for elective surgery were stratified by age: 30 infants 0.5-2 yr, 38 preschoolers 2.1-5 yr, and 27 school-age children 5.1-10 yr. They were randomized to receive 0.04 ml/kg of midazolam (0.2 mg/kg) or sufentanil (2 micrograms/kg). Hemoglobin oxygen saturation by pulse oximetry (SpO2) and sedation score were recorded prior to drug administration, at 2.5-min intervals for 10 min, at separation, and during induction with graded halothane in oxygen. Intubation was performed under deep halothane or 3 mg/kg of thiopental and 0.1 mg/kg of pancuronium. Chest wall compliance was assessed qualitatively in all patients prior to intubation. To assess the effects of a mild standardized stress on unpremedicated patients, 75 of the children with parents present were scored before and after oximeter probe placement: of these, in 63% the sedation score did not change; 33% appeared more anxious; and only 4% seemed reassured. Children of all ages reacted negatively to physicians, and 23% were crying prior to administration of drugs. Sufentanil appeared less unpleasant to receive than midazolam: children cried 46 +/- 100 versus 76 +/- 73 s (P less than 0.05), respectively, but by 7.5 min, no child was crying. Median behavior scores at maximum anxiolysis were not different, but response to sufentanil was more variable.(ABSTRACT TRUNCATED AT 250 WORDS)     

Preanesthetic Medication with Intranasal Midazolam for Brief Pediatric Surgical Procedures: Effect on Recovery and Hospital Discharge Times

Background: The perfect preanesthesia medication and its ideal route of administration are still debated, but for pediatric surgical patients undergoing brief procedures, preanesthesia medication is frequently omitted because of the concern that it will prolong the child's recovery from anesthesia. The effects of nasally administered midazolam on anesthetic recovery and hospital discharge times were determined in 88 ASA physical status 1 and 2 ambulatory surgical patients undergoing a brief surgical procedure.

Methods: Using a randomized, double-blind, placebo-controlled design, 88 ambulatory surgical patients 10-36 months of age undergoing myringotomy and tube insertion were entered into the study. All patients were randomly assigned to one of three medication groups. One group received 0.2 mg/kg intranasal midazolam; a second group received 0.3 mg/kg intranasal midazolam; and the third group received intranasal saline drops. All patients were anesthetized with nitrous oxide, oxygen, and halothane administered via mask. The duration of anesthesia lasted between 9 and 10 min. After preanesthetic medication, the children were evaluated for ease of separation and induction of anesthesia. In addition, the time from when the anesthetic was discontinued until the child recovered from anesthesia and the time the child was discharged home were recorded by a nurse observer blinded to the patient grouping.

Results: Children receiving midazolam had smoother, calmer parent-child separation and anesthesia induction scores, and their anesthesia recovery times and hospital discharge times were the same as those receiving placebo.     

Dexmedetomidine in combination with morphine PCA provides superior analgesia for shockwave lithotripsy

PURPOSE: To compare the analgesic effects of dexmedetomidine/morphine with those of tramadol/midazolam in patients undergoing extracorporeal shockwave lithotripsy (ESWL) for urinary calculi. METHODS: Sixty patients were randomized to receive either dexmedetomidine 1 micro g*kg(-1) iv followed by 0.5 micro g*kg(-1)*hr(-1) infusion together with morphine patient-controlled analgesia [(PCA); 2 mg bolus, five minutes lockout, 2 mg*hr(-1) infusion; (Group DEX)], or tramadol 1.5 mg*kg(-1) pre-mixed with midazolam 30 micro g*kg(-1) iv followed by tramadol PCA [20 mg bolus, five minute lockout, 20 mg*hr(-1) infusion; (Group TRA)]. Pain was assessed at baseline and every 15 min thereafter. Patients' and urologist's satisfaction with analgesia and sedation were determined on a seven-point scale ranging from 1 (extremely dissatisfied) to 7 (extremely satisfied). Patient's discharge time was also documented. RESULTS: Visual analogue scale scores over time were consistently lower in Group DEX compared with Group TRA (P = 0.001). Patients' satisfaction with analgesia (5 +/- 1 vs 4 +/- 2, P = 0.012) and with sedation (6 +/- 1 vs 5 +/- 1, P = 0.020), and urologist's satisfaction (6 +/- 1 vs 4 +/- 2, P = 0.001) were all higher amongst Group DEX patients compared with Group TRA. There was no difference between discharge times of patients in Group DEX compared with those in Group TRA [85 (60,115) min vs 65 (40,95) min, P = 0.069]. CONCLUSION: Dexmedetomidine in combination with morphine PCA provided better analgesia for ESWL and was associated with higher patients' and urologist's satisfaction when compared with a tramadol/midazolam PCA combination.     

Effects of fentanyl on the incidence of emergence agitation in children receiving desflurane or sevoflurane anaesthesia

BACKGROUND AND OBJECTIVE: In children, emergence agitation frequently complicates sevoflurane and desflurane anaesthesia. The effect of intravenous fentanyl 2.5 microg kg(-1) was examined on the incidence of emergence agitation in children who received desflurane or sevoflurane after midazolam premedication and intravenous thiopental induction. METHODS: One hundred and twenty children (2-7 yr) undergoing adenoidectomy or tonsillectomy, or both, were studied. All children were premedicated orally with midazolam 0.5 mg kg(-1). After intravenous induction with thiopental and atracurium to facilitate endotracheal intubation, patients were randomly assigned to one of four groups: Patients in Groups 1 and 3 received physiological saline solution, whereas patients in Groups 2 and 4 received intravenous fentanyl 2.5 microg kg(-1) during induction. Anaesthesia was maintained with sevoflurane in Groups 1 and 2 and with desflurane in Groups 3 and 4. After discontinuation of the volatile anaesthetic, the times to tracheal extubation and response to verbal stimuli (emergence time), and emergence behaviours were recorded. RESULTS: The time to tracheal extubation was significantly shorter in Groups 3 (5.2+/-1.7 min) and (6.4+/-2.1 min) than in Groups 1 (8.1+/-2.1 min) (P = 0.0001 and 0.006, respectively) and 2 (8.8+/-1.9 min) (P = 0.0001). The emergence time was significantly shorter in Group 3 (10.0+/-3.9 min) than in Groups 1 (13.8+/-4.9 min) (P = 0.017) and 2 (14.9+/-4.1 min) (P = 0.003). The incidence rate of severe agitation was 13% in Groups 1 and 3, and 7 and 10% in Groups 2 and 4, respectively (P > 0.05). CONCLUSIONS: After midazolam premedication and intravenous induction of anaesthesia with thiopental administration of intravenous fentanyl 2.5 microg kg(-1) did not provide any clinically significant benefit on emer gence agitation in children who receive sevoflurane or desflurane anaesthesia.