Comparing the response of pulse oximetry and regional cerebral oxygen saturation to hypoxia in preschool children.

Pulse oximetry and measurement of regional cerebral oxygen saturation (rcSO2) are used to monitor peripheral and cerebral oxygenation, respectively. However, the response of rcSO2 and pulse oxygen saturation (SpO2) to hypoxia in preschool children has not been previously assessed. A total of 36 preschool patients who had undergone a tonsillectomy [age, 4-6 years, American Society of Anesthesiologists grade I or II] were screened and prospectively enrolled in the present study. Hemodynamics, including rcSO2, SpO2, non-invasive blood pressure, heart rate, electrocardiogram and capnography, were continuously monitored throughout the study. Following pre-oxygenation, pressure-controlled ventilation with 100% oxygen was administered through a mask with a flow rate of 6 l/min, under total intravenous anesthesia, and the end-tidal carbon dioxide partial pressure was maintained between 30 and 40 mmHg. Tracheal intubation was then performed and ventilation was paused until SpO2 decreased to 90% or rcSO2 decreased by >10% of the baseline level. The duration from pausing of mechanical ventilation to the start of the rcSO2 decline was shorter than that of SpO2 (80.2±23.6 sec vs. 124.4±20.5 sec; P<0.001). Subsequent to the recovery of ventilation, the duration from the starting point to the increasing point of the baseline of rcSO2 was longer than that of SpO2 (84.8±24.3 sec vs. 15.2±6.8 sec; P<0.001). From the point where mechanical ventilation was paused to when rcSO2/SpO2 began to decrease, the rcSO2 and SpO2 values decreased and a significant correlation of them was observed (Pearson's correlation coefficient=0.317; P=0.027). From the time-point where mechanical ventilation was recovered to the time-point where rcSO2 or SpO2 began to increase, rcSO2 and SpO2 values decreased and a significant correlation of them was observed (Spearman's correlation coefficient=0.489; P=0.006). From the baseline to the minimum value, compared with the SpO2, the rcSO2 declined at a decreased rate (9.7±0.5% vs. 5.3±2.7%; P<0.001). The present clinical trial was registered at http://www.chictr.org.cn on 14th March 2016 (registration no. ChiCTR-OOC-16008095).

Analyzing Electroencephalography (EEG) Waves Provides a Reliable Tool to Assess the Depth of Sevoflurane Anesthesia in Pediatric Patients.

BACKGROUND Studies have reported that BIS is unreliable in children because its algorithm provides misleading information about the actual depth of anesthesia. Raw EEG analysis provides direct neurophysiologic measurement of cerebral activity. The relationship between age and EEG has rarely been reported, thus the aim of the present study was to compare raw electroencephalography (EEG) among different age groups of surgical patients under general anesthesia with 1.0 MAC sevoflurane. MATERIAL AND METHODS We enrolled 135 patients aged 0-80 years old (ASA physical status I or II) undergoing surgery, who were divided into 6 groups: 1-12 months old (group 1), 1-3 years old (group 2), 3-6 years old (group 3), 6-18 years old (group 4), 18-65 years old (group 5), and 65-80 years old (group 6). Different raw EEG waves (alpha, delta, and theta) were compared for all subjects. RESULTS The BIS values in groups 1 to 6 were 52.2±12.7, 55.0±8.0, 44.5±7.3, 43.8±7.3, 44.2±6.2, and 49.1±6.2 respectively. Compared with groups 1 and 2 (52.2±12.7, 55.0±8.0), BIS values of groups 3, 4, and 5 (44.5±7.3, 43.8±7.3, 44.2±6.2, respectively) were lower (P<0.05). Theta frequency was observed in the 6 groups. The EEG frequencies in groups 1 to 6 were 6.0 (5.5-6.0), 6.0 (5.5-6.0), 6.0 (5.5-6.0), 6.0 (6.0-7.0), 6.3 (6.0-7.0), and 6.0 (5.1-6.0), respectively. Compared with group 6, EEG frequencies in groups 4 and 5 were higher (P<0.05). BIS value was significantly correlated with EEG frequency (R²=0.063, P<0.01). CONCLUSIONS Analyzing raw EEG waves provides more accurate judgement of depth of anesthesia, especially in pediatric cases in which monitors often provide misleading values.

Intravenous dexmedetomidine pre-medication reduces the required minimum alveolar concentration of sevoflurane for smooth tracheal extubation in anesthetized children: a randomized clinical trial.

BACKGROUND: It has been known that Dexmedetomidine pre-medication enhances the effects of volatile anesthetics, reduces the need of sevoflurane, and facilitates smooth extubation in anesthetized children. This present study was designed to determine the effects of different doses of intravenous dexmedetomidine pre-medication on minimum alveolar concentration of sevoflurane for smooth tracheal extubation (MACEX) in anesthetized children. METHODS: A total of seventy-five pediatric patients, aged 3-7 years, ASA physical status I and II, and undergoing tonsillectomy were randomized to receive intravenous saline (Group D0), dexmedetomidine 1 µg∙kg-1 (Group D1), or dexmedetomidine 2 µg∙kg-1 (Group D2) approximately 10 min before anesthesia start. Sevoflurane was used for anesthesia induction and anesthesia maintenance. At the end of surgery, the initial concentration of sevoflurane for smooth tracheal extubation was determined according to the modified Dixon's "up-and-down" method. The starting sevoflurane for the first patient was 1.5% in Group D0, 1.0% in Group D1, and 0.8% in Group D2, with subsequent 0.1% up or down in next patient based on whether smooth extubation had been achieved or not in current patient. The endotreacheal tube was removed after the predetermined concentration had been maintained constant for ten minutes. All responses ("smooth" or "not smooth") to tracheal extubation and respiratory complications were assessed. RESULTS: MACEX values of sevoflurane in Group D2 (0.51 ± 0.13%) was significantly lower than in Group D1 (0.83 ± 0.10%; P < 0.001), the latter being significantly lower than in Group D0 (1.40 ± 0.12%; P < 0.001). EC95 values of sevoflurane were 0.83%, 1.07%, and 1.73% in Group D2, Group D1, and Group D0, respectively. No patient in the current study had laryngospasm. CONCLUSION: Dexmedetomidine decreased the required MACEX values of sevoflurane to achieve smooth extubation in a dose-dependent manner. Intravenous dexmedetomidine 1 µg∙kg-1 and 2 µg∙kg-1 pre-medication decreased MACEX by 41% and 64%, respectively. TRIAL REGISTRATION: Chinese Clinical Trial Registry (ChiCTR): ChiCTR-IOD-17011601 , date of registration: 09 Jun 2017, retrospectively registered.

Tracheal extubation in deeply anesthetized pediatric patients after tonsillectomy: a comparison of high-concentration sevoflurane alone and low-concentration sevoflurane in combination with dexmedetomidine pre-medication.

BACKGROUND: Dexmedetomidine can facilitate a smooth extubation process and reduce the requirement of sevoflurane and emergence agitation when administrated perioperatively. We aimed to observe the extubation process and the recovery characteristics in pediatric patients undergoing tonsillectomy while anesthetized with either high-concentration sevoflurane alone or low-concentration sevoflurane combined with pre-medication of single dose of intravenous dexmedetomidine. METHODS: Seventy-five patients (ASA I or II, aged 3-7 years) undergoing tonsillectomy were randomized into three equal groups: to receive intravenous saline (Group D0), dexmedetomidine 1 µg/kg (Group D1), or dexmedetomidine 2 µg/kg (Group D2) approximately 10 min before anesthesia. Before the end of surgery, sevoflurane were adjusted to 1.5 times, 1.0 time and 0.8 times the minimal effective concentration in groups D0, D1 and D2, respectively. The sevoflurane concentration for each group was maintained for at least 10 min before the tracheal deep-extubation was performed. The extubation event, recovery characteristics and post-op respiratory complications were recorded. RESULTS: All tracheal tubes in three groups were removed successfully during deep anesthesia. Nine patients in Group D0, three patients in Group D1, and two patients in Group D2 required oral airway to maintain a patent airway after extubation. The frequency of oral airway usage in groups D1 and D2 were significantly lower than that in Group D0. The percentages of patients with ED and the requirements of fentanyl in groups D1 and D2 were also significantly lower than those in Group D0. The time from extubation to spontaneous eye opening in Group D2 was longer than that in groups D0 and D1. The times of post-anesthesia care unit discharge in groups D0 and D2 were longer than that in Group D1. No other respiratory complications and vomiting were observed. CONCLUSION: A single dose of intravenous dexmedetomidine as pre-medication in combination with low-concentration sevoflurane at the end of surgery provided safe and smooth deep extubation condition and it also lowered the emergence agitation in sevoflurane-anaesthetized children undergoing tonsillectomy. Preoperative dexmedetomidine at 1 µg/kg did not prolong postoperative recovery time. TRIAL REGISTRATION: Chinese Clinical Trial Registry (ChiCTR): ChiCTR-IOR-16008423 , date of registration: 06 may 2016.

[Effect of single-dose dexmedetomidine on recovery profiles after sevoflurane anesthesia with spontaneous respiration in pediatric patients undergoing cleft lip and palate repair].

OBJECTIVE: To explore the effect of single-dose dexmedetomidine on recovery period after sevoflurane anesthesia with spontaneous respiration in pediatric patients undergoing cleft lip and palate repair. METHODS: A total of 60 American Society of Anesthesiologists (ASA) I-II pediatric patients undergoing cleft lip and palate repair from October to December 2013 were randomly divided into groups D and C (n = 30 each) . Dexmedetomidine 0.5 µg/kg (group D) or an equal volume of normal saline (group C) was ad ministered intravenously over a period of 10 min at 30 min before the end of surgery. Anesthesia was induced and maintained with sevoflurane under spontaneous ventilation. Heart rate, mean arterial pressure (MAP), hemoglobin oxygen saturation (SpO2), respiratory rate, tidal volume (VT) and pressure of end-tidal carbon dioxide (PETCO2) were recorded at the time before induction (T0), 30 min before the end of surgery (T1) , 20 min before the end of surgery (T2), 15 min before the end of surgery (T3), 10 min before the end of surgery (T4), the end of surgery (T5), extubation (T6), 5 min after transferal into post-anesthesia care unit (PACU) (T7) , 1 h after surgery (T8) , extubation time, length of PACU stay, fentanyl consumption and adverse events were all recorded. The incidence and severity of coughing and emergence agitation were assessed. RESULTS: Compared to T0, MAP and heart rate at T1 to T5 all decreased in two groups (P < 0.05). MAP and heart rate at T6 both increased in two groups and group C was higher than group D (P < 0.05). No inter-group differences existed in SpO2, respiratory rate, VT or PETCO2. The incidence of coughing and emergence agitation (30% and 13.3%), fentanyl consumption of group D (0.8 ± 2.1 µg) were all significantly lower than that of group C [(66.7% vs 56.7%) and (4.9 ± 6.50) µg, P < 0.05]. Length of PACU stay in group D was shorter than that in group C [(15 ± 6) vs (23 ± 19) min, P < 0.05]. No inter-group difference existed in extubation time or adverse events. CONCLUSION: A single intravenous dose of dexmedetomidine is effective in reducing emergence agitation and coughing, shortening length of PACU stay and improving the quality of recovery period after sevoflurane anesthesia in pediatric patients undergoing cleft lip and palate repair.

[Comparison of efficacy for laryngeal mask airway-Supreme(TM) versus common laryngeal mask airway in children].

OBJECTIVE: To compare the efficacy of laryngeal mask airway-Supreme(TM) versus common laryngeal mask airway in children with general anesthesia. METHODS: With local research ethics committee's approval and written informed parental consent, 100 children were randomly divided into groups L (size 2.0 common laryngeal mask airway) and S (size 2.0 laryngeal mask airway-Supreme(TM)) according to random number (n = 50 each). After anesthesia induction, a common laryngeal mask airway or laryngeal mask airway-Supreme(TM) was inserted and mechanically ventilated. Time and ease for insertion, insertion success rate, airway leak pressure, success rate and ease of disposal sputum collecting tube insertion in group S, quality of airway during anesthetic maintenance, abdominal circumference changes and complications within 24 h post-operation were measured. RESULTS: Compared with group L, abdominal circumference increased less in group S (0.90 ± 0.35 vs 0.43 ± 0.18 cm, n = 46, P < 0.01). No significant inter-group differences existed for other measurements. Disposal sputum collecting tube was successfully placed in group S(100%). CONCLUSION: In children with mechanical ventilation, laryngeal mask airway-Supreme(TM) can be effectively applied to maintain a good airway. And the incidence of gastric insufflation is lower. It is particularly useful for those requiring evacuation of gastric contents during general anesthesia.