Anesthesia Recovery Time Research Articles

Utilização experimental de hidroxiapatita sintética em alvéolos dentários de gatos domésticos (Felis catus): estudo clínico, radiográfico e histomorfométrico

A fim de avaliar a resposta biológica da hidroxiapatita sintética (HAP-91) nos alvéolos de felinos domésticos, este biomaterial foi implantado após extração do terceiro pré-molar inferior direito em 12 gatos e mantida por meio de uma membrana de celulose bacteriana. No lado esquerdo, os alvéolos foram apenas recobertos com a membrana de celulose bacteriana, formando o grupo-controle. Observou-se, durante a avaliação clínica, que todos os animais voltaram a comer normalmente ração úmida, sem apresentarem sinais de dor ou desconforto após a recuperação anestésica. A cicatrização da ferida cirúrgica ocorreu de forma satisfatória, sendo que a membrana de celulose bacteriana evitou a saída precoce da hidroxiapatita. Radiograficamente, aos 50 dias, todos os animais apresentaram radiopacidade óssea homogênea em ambos os lados. À análise histomorfométrica, observou-se adiantamento do processo de reparo do osso alveolar nos oito primeiros dias do grupo-tratado quando comparado ao grupo-controle, bem como atraso aos 30 dias, porém, aos 50 dias, ambos os grupos apresentavam porcentagem de tecido ósseo semelhante e morfologicamente normal. Os resultados sugerem que a hidroxiapatita é biocompatível, integra-se ao tecido ósseo alveolar e pode ser utilizada em felinos.

Effects of hypercapnic hyperpnea on recovery from isoflurane or sevoflurane anesthesia in horses

ObjectiveTo test the hypothesis that hypercapnic hyperpnea produced using endotracheal insufflation with 5–10% CO2 in oxygen could be used to shorten anesthetic recovery time in horses, and that recovery from sevoflurane would be faster than from isoflurane. Study designRandomized crossover study design. AnimalsEight healthy adult horses. MethodsAfter 2 hours’ administration of constant 1.2 times MAC isoflurane or sevoflurane, horses were disconnected from the anesthetic circuit and administered 0, 5, or 10% CO2 in balance O2 via endotracheal tube insufflation. End-tidal gas samples were collected to measure anesthetic washout kinetics, and arterial and venous blood samples were collected to measure respiratory gas partial pressures. Horses recovered in padded stalls without assistance, and each recovery was videotaped and evaluated by reviewers who were blinded to the anesthetic agent and insufflation treatment used. ResultsCompared to isoflurane, sevoflurane caused greater hypoventilation and was associated with longer times until standing recovery. CO2 insufflation significantly decreased anesthetic recovery time compared to insufflation with O2 alone without significantly increasing PaCO2. Pharmacokinetic parameters during recovery from isoflurane with CO2 insufflation were statistically indistinguishable from sevoflurane recovery without CO2. Neither anesthetic agent nor insufflation treatment affected recovery quality from anesthesia. Conclusions and clinical relevanceHypercapnic hyperpnea decreases time to standing without influencing anesthetic recovery quality. Although the lower blood gas solubility of sevoflurane should favor a shorter recovery time compared to isoflurane, this advantage is negated by the greater respiratory depression from sevoflurane in horses.

The Effect of Hair Colour on Anaesthetic Requirements and Recovery Time after Surgery

Patients with red hair are much more likely to have a variant of the melanocortin-1 receptor gene and this may affect sensitivity to general anaesthetics and pain response. We did a prospective, matched cohort study of 468 healthy adult patients undergoing general anaesthesia for elective surgery. All patients received an inhalational general anaesthetic. Anaesthetic drugs and doses used, hypnotic depth, recovery times, pain scores and quality of recovery scores were recorded. More men than women had red hair, so we did subgroup and multivariable analyses to account for this imbalance. There was no significant difference in recovery times, pain scores or quality of recovery scores in those with red hair. After adjusting for age, sex, American Society of Anesthesiologists physical status and duration of surgery, the recovery ratio for time to eye-opening in redheads was comparable to those with black or brown hair, 0.82 (0.57-1.19), P=0.30. We found no evidence that patient hair colour affects anaesthetic requirements or recovery characteristics in a broad range of surgical procedures.

Application of surgery clinical nursing pathway in total laryngectomy patients

Objective To explore the effects of clinical nursing pathway on patients with total laryngectomy.Methods Totals of 67 cases with total laryngectomy were divided into intensive group(34cases)and control group(33 cases) according to the random number table.Control group received nursing of routine interview before operation and cooperation during operation,while intervention group received clinical nursing pathway,including preoperative interview pathway,operation day support pathway,and postoperative interview Pathway.Many items of two groups were observed such as anxiety situation which measured by Self rating Anxiety Scale(SAS),operation starting time,bleeding during operation,anesthesia recovery time,complication during anesthesia recovery and patients' satisfaction degree.Results The SAS score of intervention group in one day before operation and before anesthesia was (46.37 ±4.78),(49.85 ±5.60),respectively,lower than that of control group ( 50.75 ± 5.82),( 53.96 ± 6.95 ),and the difference was statistically significant ( t =3.371,2.669,respectively; P ＜ 0.01 ).In intervention group,amount of bleeding during operation was (299.63 ±46.71 ) ml,anesthesia recovery time was (26.10 ± 5.08 ) min,hospital stays was ( 15.02 ± 2.74 ) d and patients'satisfaction score was(4.53 ±0.46),lower than that of control group,which in order was( 340.65 ± 59.68 ) ml,(34.50 ± 6.75)min,(19.76 ± 3.62)d,and differences between two groups were statistically significant (t =3.138,3.021,6.055,11.800,respectively;P ＜0.01).Conclusions Implementing surgery clinical nursing pathway for total laryngectomy patients can relive their anxiety,reduce operation staring time and anesthesia recovery time and reduce bleeding amount during operation and the incidence of complication during anesthesia recovery,which had improved therapeutic effect and patients' satisfaction. Key words: Clinical pathway; Laryngectomy; Intraoperative period; Nursing intervention

The anesthetic efficacy of eugenol and the essential oils of Lippia alba and Aloysia triphylla in post-larvae and sub-adults of Litopenaeus vannamei (Crustacea, Penaeidae)

The aim of this study was to evaluate the anesthesia induction and recovery times of sub-adult and post-larvae white shrimp (Litopenaeus vannamei) that were treated with eugenol and the essential oils (EOs) from Lippia alba and Aloysia triphylla. Oxidative stress parameters in the hemolymph of this species were also analyzed. The concentrations of eugenol, A. triphylla EO and L. alba EO recommended for anesthesia were 200, 300 and 750μLL−1 for sub-adults and 175, 300 and 500μLL−1 for post-larvae, respectively. The concentrations studied during the transport of sub-adults were between 20 and 50μLL−1 eugenol, 20–30μLL−1A. triphylla EO and 50μLL−1L. alba EO. For post-larvae, the optimal concentrations for transport were 20μLL−1 eugenol and between 20 and 50μLL−1A. triphylla EO. The white shrimp sub-adults that were exposed to A. triphylla EO (20μLL−1) showed increases in their total antioxidant capacities (150%), catalase (70%) and glutathione-S-transferase (615%) activity after 6h. L. alba EO (50μLL−1) and eugenol (20μLL−1) also increased GST activity (1292 and 1315%) after 6h, and eugenol (20μLL−1) decreased the total antioxidant capacity (100%). Moreover, concentrations above 30μLL−1 for the EOs of A. triphylla and L. alba and 20μLL−1 eugenol were effective at inducing anesthesia and improving the antioxidant system against reactive oxygen species (ROS) after 6h.

Effects of intravenous administration of lactated Ringer's solution on hematologic, serum biochemical, rheological, hemodynamic, and renal measurements in healthy isoflurane-anesthetized dogs

To determine the hematologic, serum biochemical, rheological, hemodynamic, and renal effects of IV administration of lactated Ringer's solution (LRS) to healthy anesthetized dogs. 4-period, 4-treatment cross-over study. 8 healthy mixed-breed dogs. Each dog was anesthetized, mechanically ventilated, instrumented, and randomly assigned to receive LRS (0, 10, 20, or 30 mL/kg/h [0, 4.5, 9.1, or 13.6 mL/lb/h]), IV, on 4 occasions separated by at least 7 days. Blood hemoglobin concentration and serum total protein, albumin, lactate, and electrolyte concentrations; PCV; colloid osmotic pressure; arterial and venous pH and blood gases (Po2; Pco2); whole blood and plasma viscosity; arterial and venous blood pressures; cardiac output; results of urinalysis; urine production; glomerular filtration rate; and anesthetic recovery times were monitored. Oxygen delivery, vascular resistance, stroke volume, pulse pressure, and blood and plasma volume were calculated. Increasing rates of LRS administration resulted in dose-dependent decreases in PCV; blood hemoglobin concentration and serum total protein and albumin concentrations; colloid osmotic pressure; and whole blood viscosity. Plasma viscosity; serum electrolyte concentrations; data from arterial and venous blood gas analysis; glomerular filtration rate; urine production; heart rate; pulse, central venous, and arterial blood pressures; pulmonary vascular resistance; and oxygen delivery did not change. Pulmonary artery pressure, stroke volume, and cardiac output increased, and systemic vascular resistance decreased. Conventional IV infusion rates of LRS to isoflurane-anesthetized dogs decreased colligative blood components; increased plasma volume, pulmonary artery pressure, and cardiac output; and did not change urine production or oxygen delivery to tissues.

Effects of sevoflurane inhalation combined with iv injection of remifentanil in cesarean section

Objective To investigate the effects ofsevoflurane inhalation combined with iv injection ofremifentanil in cesarean section, and to compared with isoflurane combined with fentanyl. Methods Forty ASA Ⅰ -Ⅱ puerperas （23-32 years old） were randomly divided into 2 groups： sevoflurane group （ I group） and isoflurane group （Ⅱ group）, 20 cases for each group. Group I was induced with mask inhalation of 3.5% of sevoflurane in 2-4 L/minutes oxygen and iv injection of remifentanil 1μg/kg, propofol 1 mg/kg and benzene cisatracurium 0.1mg/kg; group Ⅱ were induced with injectionoffentanyl0.02mg/kg, propofol2mg/kgandbenzenecisatracurium0.1 mg/kg. Anesthesia maintenance patients in I group were inhaled with 1.5%-3.5% sevoflurane, then administrated remifentanil 0.15 μ g/（kg＇min） by intravenous injection after foetus delivery; patients in I group were inspired 1.0%~2.5% isoflurane , then administrated fentanyl 0.02 mg/kg by intravenous injection after foetus delivery. Blood samples were taken from umbilical artery（UA） within 1 minute after the delivery of the baby for blood gas analysis. SBP, DBP, SPO2, HR, the anesthesia recovery time, the Apgar scores at 1, 5 and 10 minutes after the delivery of the baby and the umbilical artery blood gas analysis results of these newborns were be recorded.Results The heart rate and the blood pressure in group I maintain steady basically in induction and surgery（P 〉 0.05）. The heart rate and the blood pressure in group 11 compare Ⅰ group obvious decreased after induction （P〈 0.05）. The time of extubation （10.3 ± 3.2） minutes and opening eyes （15.4 ±2.3） minutes independently was obviously earlier in group I than in group Ⅱ（18.5 ±6.3） minutes, （25.6 ± 3.5） minutes after the surgery（P〈 0.05）.Apgar scores and umbili- cal artery blood gas analysis results of two groups were similar. （P〉 0.05）; There were no respiratory depression in the tow groups of newborns and no intraoperative awareness in the tow groups of maternal. Conclusion Anesthesia of sevoflurane inhalation combined with remifentanil is stable and effective and provide quick recovery for cesarean section. And there is no respiratory depression in the newborns. Key words: Sevoflurane ; Remifentanil; Cesarean section

Use of clove oil to anaesthetize larvae of Russian sturgeon (Acipenser gueldenstaedtii)

The efficacy of clove oil as an anaesthetic was evaluated in larvae of Russian sturgeon (Acipenser gueldenstaedtii) using four anaesthetic concentrations varying from 0.20 to 0.75 g L−1 Mean length, 13.7 ± 0.70 mm, 44 larvae placed individually to the anaesthetic bath, and induction (I-1 and I-2) and recovery times (R-1 and R-2) recorded at 18.0 ± 0.01°C. Larvae failed to respond to external stimuli ≥3 min (3.19 min) and recovered in ≥5 min (5.10 min) at 0.20 g L−1 and at the other three doses larvae reached to syncopal stage in <3 min and recovered from anaesthesia <10 min. As expected, the higher dose of clove oil resulted in significantly shorter anaesthesia induction and longer recovery times. While correlation coefficients between induction time and dose determined as negative; r = 0.87 and a positive correlation r = 0.86 has been found between doses and recovery times (P < 0.01). The study demonstrated that clove oil can be used as an effective anaesthetic in larvae of Russian sturgeon and higher dose of clove oil prolonged the recovery time.

Efficacy of laryngeal mask airway i-gel in patients undergoing laparoscopic gynecological surgery

Objective To assess the efficacy of laryngeal mask airway (LMA) i-gel used in patients undergoing laparoscopic gynecological surgery. Methods Sixty ASA Ⅰ or Ⅱ patients, aged 21-64 yr, weighing 4590 kg, undergoing elective laparoscopic gynecological surgery, were randomized into 2 groups ( n = 30 each):LMA i-gel group (group Ⅰ) and LMA Supreme group (group S) . Mallampatti test was performed before operation in both groups. Anesthesia was induced with target-controlled infusion of propofol (target plasma concentration 2.5-4.0 μg/ml) and remifentanil (target plasma concentration 3-6 ng/ml) . After the patients lost consciousness, rocuronium 0.6 mg/kg was given to facilitate the LMA insertion. LMA i-gel and LMA Supreme were inserted in I and S groups respectively. A gastric tube was inserted through the drain tube of the LMA. In group S the air was injected into the cuff to make intracuff pressure reach 60 cm H2O after successful LMA insertion. The LMA placement time, the number of attempts of LMA insertion, the number of attempts of gastric tube placement, the airway sealing pressure, the parameters of hemodynamics and ventilation, and complications (sore throat, odynopliagia,hoarseness) were recorded. The fiberoptic laryngoscopy scores were assessed after successful LMA placement. The anesthesia time and recovery time were also recorded. Results There was no significant difference in the anesthesia time, recovery time, LMA placement time, fiberoptic bronchoscopy scores and the parameters of hemodynamics and ventilation between the two group. The success rates of LMA and gastric tube placement were 100% in both groups. The airway sealing pressure was significantly higher, while the incidence of sore throat and odynopliagia was significantly lower in group I than in group S. Conclusion LMA i-gel provides adequate ventilation during operation with fewer complications and can be used effectively for gynecological laparoscopic surgery. Key words: Laryngeal mask; Respiration,artificial; Laparoscopy

Anesthetic effects of clove oil and lidocaine-HCl on marine medaka (Oryzias dancena)

Fish may be anesthetized for various experimental and practical purposes, primarily to immobilize them in order to facilitate handling. Marine medaka (Oryzias dancena) is a teleost fish used in marine ecotoxicology studies. Despite the importance of anesthesia in handling experimental fish, the effects of anesthesia in marine medaka have not yet been investigated. In this study, the authors evaluated the anesthetic effects (time required for anesthesia to take effect and recovery time) of two anesthetic agents, clove oil and lidocaine-HCl, on marine medaka. They anesthetized fish at different water temperatures (23 °C, 26 °C and 29 °C) and using different concentrations of clove oil (50 ppm, 75 ppm, 100 ppm, 125 ppm, 150 ppm and 175 ppm) or lidocaine-HCl (300 ppm, 400 ppm, 500 ppm, 600 ppm, 700 ppm and 800 ppm). The time required for anesthesia to take effect decreased significantly as both anesthetic concentration and water temperature increased for both clove oil and lidocaine-HCl. To anesthetize marine medaka within approximately 1 min, the optimal concentrations for clove oil were 125 ppm at 23 °C, 100 ppm at 26 °C and 75 ppm at 29 °C and for lidocaine-HCl were 800 ppm at 23 °C and 700 ppm at both 26 °C and 29 °C. The authors also compared anesthetic effects in marine medaka of different sizes. Both anesthetic exposure time and recovery time were significantly shorter for smaller fish than for larger fish. These results provide a useful foundation for the laboratory handling of marine medaka.

Impact of Dexmedetomidine total intravenous anaesthesia on obese patients

Objective To compare the impact on the circulation function and anesthetic recovery between the obese perioperative patients with elective modi?ed radical mastectomy received dexmedetomidine total intravenous anaesthesia and the ones received remifentanil total intravenous anaesthesia; and to explore the anti-pain effect and side-effects of the two group patients. Methods In this prospective randomized double-blind study, 56 cases ASA Ⅰ～Ⅱ and age 34 ～ 60yr morbidly obese patients who were scheduled for modi?ed radical mastectomy, were allocated into two groups averagely.Dexmedetomidine group received i.v. dexmedetomidine 1 μ g/kg as preinduction within 15 minutes, then muscular to maintain anaesthesia. Record hemodynamics changes and anaesthesia drug dose during the operation. Record the anaesthetic recovery time, and observe the postoperative adverse reaction. Results Propofol-remifentanil and propofol-dexmedetomidine got similar intraoperative hemodynamic responses;the mean arterial pressure was similar in the two groups(P＞0.05), but heart rate was higher after extubation in remifentanil group (P＜ 0.05). Propofol doses for induction and maintenance of anesthesia was lower within dexmedetomidine group. The need for earliest analgesic administration was delayed, and the incidence rate of postoperative respiratory depression, nausea, vomiting, shivering were lower in dexmedetomidine group (P＜0.05); but the recovery time was longer(P＜0.05). Bradycardia was similar between two groups (P＞ 0.05). Conclusion Dexmedetomidine total intravenous anesthesia provide stable hemodynamics for the morbidly obese patients with elective modi?ed radical mastectomy; and can decrease propofol consumption and undesirable side-effects, delay postoperative analgesics requirement, but it fail to facilitate anesthetic recovery. Key words: Dexmedetomidine; Anesthsia; Obesity

Intraosseous Anesthesia in Hemodynamic Studies in Children with Cardiopathy

Intraosseous (IO) access has been used with good results in emergency situations, when venous access is not available for fluids and drugs infusion. The objective of this study was to evaluate IO a useful technique for anesthesia and fluids infusion during hemodynamic studies and when peripheral intravascular access is unobtainable. The setting was an university hospital hemodynamics unit, and the subjects were twenty one infants with congenital heart disease enrolled for elective hemodynamic study diagnosis. This study compared the effectiveness of IO access in relation to IV access for infusion of anesthetics agents (ketamine, midazolam, and fentanyl) and fluids during hemodynamic studies. The anesthetic induction time, procedure duration, anesthesia recovery time, adequate hydration, and IV and IO puncture complications were compared between groups. The puncture time was significantly smaller in IO group (3.6 min) that in IV group (9.6 min). The anesthetic onset time (56.3 second) for the IV group was faster than IO group (71.3 second). No significant difference between groups were found in relation to hydration (IV group, 315.5 mL vs IO group, 293.2 mL), and anesthesia recovery time (IO group, 65.2 min vs IV group, 55.0 min). The puncture site was reevaluated after 7 and 15 days without signs of infection or other complications. Results showed superiority for IO infusion when considering the puncture time of the procedure. Due to its easy manipulation and efficiency, hydration and anesthesia by IO access was satisfactory for hemodynamic studies without the necessity of other infusion access.

Comparison of pre- vs. post-incisional caudal bupivacaine for postoperative analgesia in unilateral pediatric herniorrhaphy: A double-blind randomized clinical trial

Introduction:This study was designed to evaluate the pre- vs. post-incisional analgesic efficacy of bupivacaine administered caudally in children undergoing unilateral hernia repair.Methods:Fifty children aged 6 months to 6 years were included in the study. Children were divided blindly between the two groups to receive pre- vs. post-incisional caudal bupivacaine. The preincisional group received 1 ml/kg of 0.125% bupivacaine caudally after induction of anesthesia and the postincisional group received the same dose caudally at the end of surgery. Heart rate, SaO2, end tidal CO2, and noninvasive arterial blood pressure were recorded every 10 min. The duration of surgery, extubation time, and duration of recovery period were also recorded. The pain scores were measured with using an Oucher chart in the recovery room, 2, 4, 6, 12, and 24 h after surgery. Time to first analgesia, numbers of supplementary analgesics required by each child in a 24-h period and total analgesic consumptions were recorded. Any local and systemic complications were recorded. Quantitative data were compared using a two-tailed t-test. Sex distribution and frequency of acetaminophen consumption were measured using χ2 test. P < 0.05 was considered statistically significant.Results:The Oucher pain scale at 4, 6, 12, and 24 h after surgery, the total analgesic consumption and the numbers of demand for supplemental acetaminophen were lower statistically in preincisional group (P < 0.05). Extubation time and duration were higher in preincisional group (P < 0.05). Mean changes of heart rates were statistically lower during the anesthesia period and recovery time in preincisional group (P < 0.05).Conclusion:Preincisional caudal analgesia with a single injection of 0.125% bupivacaine is more effective than the postincisional one for postoperative pain relief and analgesic consumption in unilateral pediatric herniorrhaphy.

A comparison of the sedative, hemodynamic, and respiratory effects of dexmedetomidine and propofol in children undergoing magnetic resonance imaging

Aim:To compare the sedative, hemodynamic, and respiratory effects of dexmedetomidine and propofol in children undergoing magnetic resonance imaging procedures.Methods:Sixty children between the age of 1 to 7 years were randomly distributed into two groups: The dexmedetomidine (D) group received 1 μg/kg initial dose followed by continuous infusion of 0.5 μg/kg/h, and the propofol group (P) received 3 mg/kg initial dose, followed by a continuous infusion of 100 μg/kg/min. Inadequate sedation was defined as difficulty in completing the procedure because of the child's movement during magnetic resonance imaging. Mean arterial pressure (MAP), heart rate, peripheral oxygen saturation, and respiratory rate (RR) were recorded during the study.Result:The onset of sedation, recovery, and discharge time were significantly shorter in group P than in group D. MAP, heart rate, and RR decreased during sedation from the baseline values in both groups. MAP and RR were significantly lower in group P than in group D during sedation. Dexmedetomidine and propofol provided adequate sedation in most of the children.Conclusion:We conclude that although propofol provided faster anesthetic induction and recovery times, it caused hypotension and desaturation. Dexmedetomidine could be an alternative, reliable sedative drug to propofol in selected patients.

A comparison of acepromazine-buprenorphine and medetomidine-buprenorphine for preanesthetic medication of dogs

To assess sedative and cardiopulmonary effects of premedication with a medetomidine-buprenorphine or acepromazine-buprenorphine combination in dogs anesthetized with propofol and isoflurane. Randomized controlled clinical trial. 90 dogs undergoing routine surgical and diagnostic procedures. Dogs were randomly assigned to 1 of 3 premedication groups: group 1 (acepromazine, 0.03 mg/kg [0.014 mg/lb], IM; buprenorphine, 0.02 mg/kg [0.009 mg/lb], IM), 2 (medetomidine, 5 μg/kg [2.3 μg/lb], IM; buprenorphine, 0.02 mg/kg, IM), or 3 (medetomidine, 10 μg/kg [4.5 μg/lb], IM; buprenorphine, 0.02 mg/kg, IM). Anesthesia was induced with propofol and maintained with isoflurane in oxygen. Simple descriptive scores for sedation were assigned 15 minutes (groups 2 and 3) and 30 minutes (group 1) after premedication administration. Basic cardiopulmonary data were recorded throughout the anesthetic period. Times to recovery from anesthesia were recorded. Sedation scores did not differ significantly among groups. Mean and diastolic blood pressures were significantly lower and heart rate was significantly higher in group 1 than in the other groups. Mean end-tidal partial pressure of CO(2) was significantly lower and respiratory rate was significantly higher in group 1 than in the other groups. There were no significant differences in anesthetic recovery times between groups. Results suggested that either acepromazine or medetomidine could be used in combination with buprenorphine for premedication of dogs anesthetized with propofol and isoflurane for routine surgical and diagnostic procedures. Arterial blood pressure was better maintained with the medetomidine-buprenorphine combinations, but tissue perfusion was not investigated.

Efficacy of different concentrations of sevoflurane administered through a face mask for magnetic resonance imaging in children

The main aim of this study was to use a non-invasive method such as a face mask to maintain anesthesia in children during magnetic resonance imaging (MRI). The secondary aim was to ascertain hemodynamic-respiration parameters, recovery time and complications of anesthesia with the administration of different concentrations of sevoflurane. This prospective and randomized study included 96 ASA I-II children, aged 1-10, scheduled to undergo MRI with anesthesia with sevoflurane through a face mask. All patients were administered midazolam 0.5 mg·kg(-1) orally 30 min before anesthesia induction. Sevoflurane 8% was given to induce anesthesia under assisted-controlled ventilation for 2 min, and an intravenous route was opened on the hand. Three different concentrations of sevoflurane were administered through a face mask under spontaneous respiration to maintain anesthesia. A mixture of sevoflurane, oxygen, and air of 5 l·min(-1) was given through a face mask for anesthesia. Group 1 (n = 32) received 1.5% sevoflurane, Group 2 (n = 32) 1.25% sevoflurane, and Group 3 (n = 32) 1.0% sevoflurane. Recovery time, removal from the MRI room, postanesthesia care unit discharge data, and complications were also recorded. Heart rate, mean arterial pressure (MAP), peripheral oxygen saturation (SpO(2)), respiration rate, and anesthesia adequacy were recorded every 5 min from the time of induction until completion of the MRI. All three groups were similar in demographic and hemodynamic respiratory features. MRI was successfully performed in 96.6% of all patients without additional intervention. Sevoflurane concentrations were increased for a short time in one patient in Group 1 and in two patients in Group 3. Oxygen flow was increased in one patient in Group 1 and in one patient in Group 2 as SpO(2) was lower than 95%. The mean time to eye opening (from discontinuation of sevoflurane to eye opening) was 155.8 ± 50.0 s in Group 1, 89.5 ± 16.0 s in Group 2, and 53.5 ± 10.0 s in Group 3; differences between the groups were statistically significant (P = 0.001). Airways were not used on any of the patients, and none vomited or required endotracheal intubation or laryngeal mask anesthesia. We believe that the administration of sevoflurane at a concentration of 1% via a face mask under spontaneous respiration may provide light anesthesia without complications to induce an unarousable sleep for children during MRI.

GABAAReceptors in the Pontine Reticular Formation of C57BL/6J Mouse Modulate Neurochemical, Electrographic, and Behavioral Phenotypes of Wakefulness

Drugs that potentiate transmission at GABA(A) receptors are widely used to enhance sleep and to cause general anesthesia. The mechanisms underlying these effects are unknown. This study tested the hypothesis that GABA(A) receptors in the pontine reticular nucleus, oral part (PnO) of mouse modulate five phenotypes of arousal: sleep and wakefulness, cortical electroencephalogram (EEG) activity, acetylcholine (ACh) release in the PnO, breathing, and recovery time from general anesthesia. Microinjections into the PnO of saline (vehicle control), the GABA(A) receptor agonist muscimol, muscimol with the GABA(A) receptor antagonist bicuculline, and bicuculline alone were performed in male C57BL/6J mice (n = 33) implanted with EEG recording electrodes. Muscimol caused a significant increase in wakefulness and decrease in rapid eye movement (REM) and non-REM (NREM) sleep. These effects were reversed by coadministration of bicuculline. Bicuculline administered alone caused a significant decrease in wakefulness and increase in NREM sleep and REM sleep. Muscimol significantly increased EEG power in the delta range (0.5-4 Hz) during wakefulness and in the theta range (4-9 Hz) during REM sleep. Dialysis delivery of bicuculline to the PnO of male mice (n = 18) anesthetized with isoflurane significantly increased ACh release in the PnO, decreased breathing rate, and increased anesthesia recovery time. All drug effects were concentration dependent. The effects on phenotypes of arousal support the conclusion that GABA(A) receptors in the PnO promote wakefulness and suggest that increasing GABAergic transmission in the PnO may be one mechanism underlying the phenomenon of paradoxical behavioral activation by some benzodiazepines.

Comparison of anaesthetic and cardiorespiratory effects of xylazine or medetomidine in combination with tiletamine/zolazepam in pigs

Two different combinations of anaesthetics were evaluated and compared in a prospective randomised crossover experimental study in pigs. One of the two combinations was administered intramuscularly to each of six...

A Model of Intravenous Regional Anesthesia in Rats

We developed an IV regional anesthesia (IVRA) model using the tails of rats to allow preclinical evaluation of the safety and efficacy of drugs used in IVRA and analgesia. Three sequential experiments were designed to determine local anesthetic and analgesic effects of drugs injected IV in the tail. The anesthesia was assessed by monitoring the response of the tail-clamp (RTC) test on the tail, whereas the analgesia was assessed by recording the latency in the tail-flick test on the tail. In the first 2 experiments, we studied the effects of different environmental temperatures (15 degrees C, 25 degrees C, and 37 degrees C) and length of tourniquet time on the tail-flick and tail-clamp tests, respectively. Based on the outcomes of these 2 experiments, the pharmacological effects of 1% lidocaine (L group) and 0.5% bupivacaine (B group) were compared with normal saline (NS group) to evaluate this model in experiment 3. In experiment 1, compared with its baseline, tail-flick latency increased rapidly in the 15 degrees C group (P < 0.0001), whereas there were no changes in tail-flick latency in the 25 degrees C group (P = 0.3640) and the 37 degrees C group (P = 0.0641) after the first 20 minutes of tail submersion in a water bath. RTCs in all rats were positive during the entire observation period. In experiment 2, tail-flick latency did not change compared with baseline tail-flick latency after the first 20 minutes of tourniquet application (P = 0.0902), but significantly increased at the 30-, 40-, 50-, and 60-minute intervals (P = 0.0001). RTCs in all rats were positive during the experiment. In experiment 3, local anesthesia was generated in the tail (distal to the tourniquet) in the L and B groups with a similar onset time of anesthesia (approximately 1 minute), but with a longer recovery time of anesthesia and analgesia in the B group (56.0 +/- 22.0 minutes) than the L group (31.0 +/- 19.0 minutes), whereas no anesthetic and analgesic effects were observed in the NS group. A reliable model for studying IVRA and analgesia has been developed in rats.

Comparison of intravenous general anaesthesia vs endotracheal intubation in the surgical management of juvenile onset recurrent respiratory papillomatosis

Conclusions: Both intravenous general anaesthesia (IVGA) and general anaesthesia with endotracheal intubation (GA with ET) are applicable for the procedure of juvenile onset recurrent respiratory papillomatosis (JO-RRP). GA with ET was found to be better for JO-RRP patients with dyspnoea, as it provided better stabilization of the vital signs with fewer postoperative complications. Objectives: To evaluate the safety and efficacy of two different anaesthetic techniques in the removal of JO-RRP. Methods: A total of 52 JO-RRP patients with mild dyspnoea were included in the study. Each case underwent two procedures, one by IVGA and the other by GA with ET. A total of 104 procedures were performed. The effectiveness and safety of the two anaesthetic techniques were pairwise compared. Results: There were no significant differences in anaesthetic recovery time, operative time or postoperative voice quality between the two anaesthetic groups. However, significant differences in heart rate, oxygen saturation and carbon dioxide saturation were observed. Some patients who underwent IVGA developed apnoea (28.8%) and laryngeal spasm (19.2%). These complications were not observed in the GA with ET group.