BackgroundDexmedetomidine 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.MethodsSeventy-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.ResultsAll 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.ConclusionA 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 registrationChinese Clinical Trial Registry (ChiCTR): ChiCTR-IOR-16008423, date of registration: 06 may 2016.

BackgroundIt 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.MethodsA 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.ResultsMACEX 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.ConclusionDexmedetomidine 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 registrationChinese Clinical Trial Registry (ChiCTR): ChiCTR-IOD-17011601, date of registration: 09 Jun 2017, retrospectively registered.

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/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 (R 2 =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.

Pulse oximetry and measurement of regional cerebral oxygen saturation (rcSO 2) are used to monitor peripheral and cerebral oxygenation, respectively. However, the response of rcSO 2 and pulse oxygen saturation (SpO 2) 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 rcSO 2 , SpO 2 , 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 SpO 2 decreased to 90% or rcSO 2 decreased by >10% of the baseline level. The duration from pausing of mechanical ventilation to the start of the rcSO 2 decline was shorter than that of SpO 2 (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 rcSO 2 was longer than that of SpO 2 (84.8±24.3 sec vs. 15.2±6.8 sec; P<0.001). From the point where mechanical ventilation was paused to when rcSO 2 /SpO 2 began to decrease, the rcSO 2 and SpO 2 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 rcSO 2 or SpO 2 began to increase, rcSO 2 and SpO 2 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 SpO 2 , the rcSO 2 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).