The influence of additional nitrous oxide during rapid anesthetic induction with sevoflurane

In this study, a vital capacity rapid inhalation induction technique was used, and 4.5% sevoflurane in 100% oxygen and with 66% nitrous oxide in oxygen were compared. Each anesthetic gas was used on a group of 17 unpre-medicated volunteers. The induction time of sevoflurane in nitrous oxide with oxygen and sevoflurane in oxygen were 55±10 s and 81±22 s (SD), respectively, (P<0.05). Notable cardiovascular instability was not observed in either group. Serious complications such as laryngospasm, breath holding, and excessive salivation were not observed in either group. In conclusion, the addition of nitrous oxide to sevoflurane in oxygen is a useful technique because there were no increases in complications during the accelerated rapidity of induction.     

Effects of sevoflurane with or without nitrous oxide on cardiac contractility and sinoatrial node rate

Cardiac effects of sevoflurane (SE) with or without nitrous oxide were examined in the canine blood-perfused papillalry muscle and sinoatrial node preparations. Although SE depressed developed tension (DT), mean arterial pressure (MAP) and heart rate of the donor dog (DHR) dose dependently, sinoatrial rate (SAR) was not changed significantly. No significant chanages in MAP, DHR and SAR were observed with the addition of nitrous oxide to SE. However, the addition of nitrous oxide to SE resulted in significant decrease of DT.These results suggest that SE depresses BP and cardiac contractility dose dependently, but dose not change heart rate. The combination of nitrous oxide and SE may produce less cardiovascular depressant effect at a given MAC level than SE given alone.(Manabe M, Ookawa I, Nonaka A et al.: Effects of sevoflurane with or without nitrous oxide on cardiac contractility and Sinoatrial node rate. J Anesth 3: 145–148, 1989)     

丙泊酚复合雷米芬太尼或氧化亚氮用于妇科腹腔镜诊疗手术麻醉苏醒的比较

目的对丙泊酚复合雷米芬太尼或氧化亚氮用于妇科腹腔镜诊疗术后麻醉苏醒、早期拔管进行比较。方法选择ASAⅠ级,临床诊断不孕,拟于气管内插管的全麻下择期行腹腔镜检查及治疗的患者45例,随机分为三组:丙泊酚3μg/ml组(A组),丙泊酚2μg/ml组(B组)和氧化亚氮组(C组),每组15例。三组患者均为丙泊酚靶控输注(TCI)给药诱导及术中维持麻醉,罗库溴铵维持肌松。A组:维持丙泊酚靶浓度3μg/ml不变,雷米芬太尼根据血液动力学变化按0~1μg.kg-1.min-1输注给药,维持血液动力学稳定。B组:维持丙泊酚靶浓度2μg/ml不变,同样通过调整雷米芬太尼的给药速度维持血液动力学稳定。C组:丙泊酚TCI诱导,气管内插管后伍用氧化亚氮吸入维持麻醉。呼气末氧化亚氮浓度保持(65±1)%,通过调整丙泊酚的靶浓度来维持血液动力学稳定。三组患者均在手术结束时同时停麻醉药。以停麻醉的时间为零点计时,记录呼患者睁眼时间、气管拔管时间及答问切题时间。结果在睁眼时间、拔管时间和答问切题时间三项观察指标中,各组之间差异均有极显著意义(P<0.01)。B组患者睁眼时间(4.5±2.1)min、拔管时间(5.4±2.3)min、答问切题时间(8.1±2.8)min最短,说明麻醉苏醒最快;C组分别为(11.6±3.4)、(12.7±3.6)、(20.2±4.5)min,患者苏醒最慢;A组分别为(8.7±2.9)、(10.0±3.2)、(14.5±3.8)min,处于中间。结论低浓度丙泊酚TCI(2μg/ml)复合雷米芬太尼用于妇科腹腔镜诊疗手术,可使患者术后清醒快,恢复迅速。     

脑状态指数在七氟醚或丙泊酚诱导时的变化

目的 观察七氟醚或丙泊酚麻醉时脑状态指数(CSI)的变化.方法 30例腹腔镜手术患者随机均分成七氟醚组(S组)和丙泊酚组(P组).麻醉诱导:S组吸入2%的七氟醚,每隔1分钟增加1%;P组每隔1分钟重复给予15 mg丙泊酚,直至患者意识消失.记录患者诱导期的CSI数值,并对患者的镇静程度采用警觉/镇静评分(OAA/S)标准评分.结果 S组与P组术前CSI基础值差异无统计学意义,随着麻醉的加深,两组的CSI数值均明显下降(P<0.01),至OAA/S 1分时S组与P组的CSI数值较OAA/S 5分时明显下降(P<0.05或P<0.01),S组与P组的CSI与OAA/S的相关系数r分别为0.843和0.812.结论 CSI监测可反映七氟醚或丙泊酚麻醉时的麻醉深度.     

Single-breath inhalation induction of sevoflurane anaesthesia with and without nitrous oxide: a feasibility study in adults and comparison with an intravenous bolus of propofol

The induction characteristics of sevoflurane in nitrous oxide and oxygen were compared with sevoflurane in oxygen alone and a propofol infusion. A vital capacity technique was used for the gaseous induction groups using a Mapleson A system and a 4-litre reservoir bag. Four end-points of anaesthesia were recorded: time to cessation of finger tapping, time to loss of eyelash reflex, time to jaw relaxation and time to regular settled breathing after laryngeal mask airway insertion. We also recorded sequential blood pressure and pulse rate, the incidence of adverse airway events and the acceptability of the induction technique. Propofol had a faster time to cessation of finger tapping (p <0.05) and jaw relaxation (p <0.01). These differences disappeared with the final induction stage and sevoflurane in nitrous oxide and oxygen had the faster time to regular settled breathing, though this did not reach statistical significance. Cardiovascular stability was good and comparable in all groups. There were few adverse airway events in any group and none caused oxygen saturation to fall below 96%. There was more excitation in the gaseous induction groups, though this did not interfere with induction. Patient satisfaction with induction was high.     

Rapid induction with 7% sevoflurane inhalation—not the single-breath method

The usefulness of the rapid anesthesia induction method with 7% sevoflurane, not the single-breath method, was investigated in 88 patients with ASA physical status 1. Anesthesia was induced with 3 l·min⁻¹ nitrous oxide in 3 l·min⁻¹ oxygen and sevoflurane 7% for 3 min (group A), 7% for 5 min (group B), 7% for 7 min (group C), and 5% for 7 min in conventional induction (group D). There were 22 patients in each group. Each sevoflurane concentration was given at the same time as the start of nitrous oxide inhalation except for group D. The changes in blood pressure and heart rate were the smallest in group A. The time for the loss of consciousness was shorter in groups A (47.2 s), B (44.9 s), and C (49.8 s) than in group D (73.4 s). During induction, body movements were seen in 18.2% in group A and 13.6% in the other 3 groups, but no other complications such as coughing, breath holding, or laryngospasm were seen in any group. In conclusion, the anesthesia induction method with 3 min of 7% sevoflurane inhalation was useful for rapid induction.     

三种麻醉方法在维持期间血流动力学的变化

目的：观察异丙酚／阿芬太尼、七氟醚／笑气以及安氟醚／笑气等三种麻醉维持期间血流动力学指标的变化。方法：４５例病人随机分为三组，每组１５例，麻醉快速诱导后经气管插入特殊的ＴＴＤ导管，麻醉维持分别采用０．１ｍｇ·ｋｇ－１·ｍｉｎ－１异丙酚和１μｇ·ｋｇ－１·ｍｉｎ－１阿芬太尼静脉泵入（Ｐ／Ａ组），１％七氟醚－６６％笑气（Ｓ／Ｎ组）或１％安氟醚－６６％笑气吸入（Ｅ／Ｎ组）。于麻醉诱导后３０分钟、手术开始后３０分钟、４５分钟、６０分钟以及术毕测定ＭＡＰ、ＣＶＰ、ＣＯ、ＣＩ和ＳＶＲ等血流动力学指标的变化。结果：在ＡＳＡⅠ～Ⅱ级的病人，临床麻醉剂量的异丙酚／阿芬太尼、七氟醚／笑气和安氟醚／笑气麻醉对血流动力学指标的影响轻微。结论：三种麻醉方法对心血管功能的影响程度相似。     

脑电双频指数指导下不同麻醉诱导方式对喉罩插入条件的影响

目的 观察脑电双频指数(BIS)指导下不同麻醉诱导方式对喉罩插入条件的影响.方法 60例择期行宫腔镜手术患者,ASAⅠ或Ⅱ级,根据诱导方式的不同随机均分为三组:七氟醚复合丙泊酚组(SP组)、七氟醚组(S组)及丙泊酚组(P组).SP组肺活量法吸入七氟醚,待患者意识消失后静脉注射丙泊酚;S组以肺活量法吸入七氟醚;P组静脉泵注丙泊酚.BIS值稳定于40～50超过20 s后插入喉罩.记录诱导开始至成功插入喉罩的时间及成功率;评估下颌松弛度评分和喉罩插入后咳嗽及肢体运动评分.结果 诱导至喉罩插入时间S组＞SP组＞P组(P＜0.05).呼吸暂停发生率P组(40％)明显高于SP和S组(均为0)(P＜0.05).不自主肢体运动发生率P组高于SP和S组(35％ vs 5％和10％,P＜0.05).结论 BIS指导下七氟醚复合丙泊酚诱导较丙泊酚或七氟醚诱导能提供更好的喉罩插入条件.     

Desflurane requirements for laryngeal mask airway insertion during inhalation induction

Purpose  We hypothesized that the simultaneous use of low concentrations (<6%) of desflurane, nitrous oxide (N₂O), and fentanyl would allow a laryngeal mask airway (LMA) to be inserted safely with inhalation induction of desflurane, even in nonparalyzed patients. This prospective, observational study was performed to determine the 50% effective concentration (EC₅₀) of desflurane for LMA insertion in such patients. Methods  Twenty-two adult patients undergoing ambulatory surgical procedures under general anesthesia using an LMA were included in the study. Fentanyl was administered intravenously at 1.5 μg·kg⁻¹, and anesthesia was induced with desflurane in 50% N₂O and oxygen, using a normal tidal volume breathing technique. Subsequently, a preselected steady-state end-tidal desflurane concentration was maintained for 10 min before insertion of the LMA. Successful LMA insertion was defined as the absence of adverse airway responses until cuff inflation. Target concentrations of desflurane for LMA insertion were determined using a modified Dixon’s up-and-down method (starting dose, 5%; step size, 0.5%). Results  All 22 patients completed the study without adverse events related to airway irritation. The EC₅₀ of desflurane for insertion of the LMA was determined to be 3.61 ± 0.31%, and the 95% confidence interval (CI) of the EC₅₀ obtained using probit analysis was 3.13–3.90. Conclusion  We demonstrated that N₂O-desflurane inhalation induction with a normal tidal breathing technique after premedication with fentanyl can be used safely without any adverse airway events in nonparalyzed patients. In such patients, the EC₅₀ of desflurane for successful LMA insertion was 3.61 ± 0.31% (95% CI, 3.13–3.90).     

A comparison of 8% and 12% sevoflurane for inhalation induction in adults

Sevoflurane is a non-pungent volatile anaesthetic agent with a low blood-gas solubility coefficient. It has been studied in concentrations of up to 8% for induction of anaesthesia. Previous work has suggested that there may be a ceiling effect with increasing concentration of sevoflurane above 6%, but there are no published studies using 12% sevoflurane. This study compared 8 and 12% sevoflurane to induce anaesthesia in adults. Sevoflurane was administered using two adapted datum vaporisers with the interlock removed. Induction with 12% sevoflurane compared to 8% sevoflurane produced a significant decrease in the time to achieve central pupils, corresponding to surgical anaesthesia and the third part of Guedel's stage 3 of anaesthesia (mean time (SD) 201 s (81) and 247 s (39), respectively, p < 0.05). Twelve-percent sevoflurane produced a similar stable cardiovascular profile to 8% sevoflurane, and there was no increase in respiratory complications.     

七氟醚吸入麻醉与丙泊酚复合七氟醚麻醉对血糖的影响

目的 探讨七氟醚吸入麻醉对血糖水平的影响.方法 30例全麻患者随机分成七氟醚吸人麻醉组(A组)和丙泊酚复合七氟醚麻醉组(B组),每组15例.观察术前以及手术2h时的血糖浓度.结果 A、B两组手术2h的血糖均比术前明显升高[(6.23±1.45)mmol/L vs.(4.86±0.85)mmol/L和(6.66±1.48)mmol/L vs.(5.11±0.43)mmol/L](P<0.05);但组间差异无统计学意义.结论 七氟醚吸人麻醉与内泊酚复合七氟醚麻醉均不能抑制应激性血糖升高.     

氧化亚氮对双腔喉罩套囊内压的影响

目的 观察麻醉期间吸人氧化亚氮(N2O)对双腔喉罩(PLMA)套囊内压的影响及几种处理力法的效果.方法 择期手术患者60例,随机均分成四组,分别在PLMA套囊内预充空气(A组和D组)、50%N2O(B组)、生理盐水(C组)使套囊初始压力至20mm Hg.术中吸入50%N2O,持续监测喉罩套囊内压.其中D组套囊内压一旦超过40mm Hg即抽出套囊内部分气体使压力降至初始水平.结果 A组喉罩套囊内压持续升高,B组和C组保持平稳,15min后三组喉罩套囊内压差异有统计学意义(P<0.05).D组在(20±7)min时进行第一次抽气,抽气1～2次后D组套囊内压明显低于A组(P<0.05).手术结束时,A组套囊内压明显高于B、C、D组(P<0.05).拔除喉罩后,A组套囊内出现血迹的发生率明显高于B组(P<0.05).结论 麻醉期间吸入N2O使PLMA套囊内压明显升高,喉罩套囊内预充与吸入麻醉相同浓度的N2O、生理盐水或间歇抽出套囊内部分气体能有效防止套囊内压过度升高.     

Effects of sevoflurane and/or nitrous oxide on bacterial growth in in vitro culture conditions

The aim of this study was to determine the role of sevoflurane and/or nitrous oxide on bacterial growth under conditions in vitro similar to those of clinical practice. We assessed these effects on Pseudomonas aeruginosa, Acinetobacter lwoffii, and Staphylococcus aureus growth. Bacterial inoculums were prepared from reference strains in nutritive broth. Airtight chambers were filled with bacterial suspensions. Each strain was studied with and without exposure to sevoflurane and/or nitrous oxide at baseline, after 1 and 3 h. Serial dilutions and agar plates were made and the colonies were counted. P. aeruginosa were grown after exposure to the nitrous oxide alone (2.8 × 10³ colony-forming units/ml; CFU ml⁻¹) after 3 h according to the control (P < 0.05). A. lwoffii were grown after exposure to the nitrous oxide and sevoflurane with nitrous oxide (8.7 × 10³ and 8.0 × 10³ CFU ml⁻¹) (P < 0.05), respectively. There were no changes in S. aureus growth in controls and anesthesia groups. We conclude that the effects of anesthetic agents on bacterial growth may change owing to the type of anesthetic and microorganism.     

Effective concentration 50 for propofol with and without 67% nitrous oxide

The Effective Blood Concentration (EC) of propofol required to prevent response to surgical incision was determined in 65 ASA I or II female patients breathing either 100% oxygen or 67% N₂O in oxygen. Propofol was administered via a microcomputer-controlled infusion system programmed to maintain the blood propofol concentration at predetermined target values. The blood propofol concentrations predicted by the micro-computer were validated by measurement of whole blood propofol concentration. Predicted and measured concentrations differed during infusion of propofol, but became similar after discontinuing the infusion for at least 90 s, suggesting that equilibration within the central compartment was incomplete during infusion. The response to the initial incision was observed and probit analysis used to determine the predicted blood concentration at which 50% of patients responded. The predicted EC50 for propofol/N₂O/ O₂ and propofol/O₂ was 4.5 μg ml^-1 and 6.0 μg ml^-1 respectively, and the measured EC50 propofol/N₂O/ O₂ and propofol/O₂ was 5.36 μg ml^-1 and 8.1 μg ml^-1, 67% nitrous oxide in oxygen reducing the predicted EC50 by 25% and the measured EC50 of propofol by 33%. The predicted EC may be more representative of the equilibrated concentration in the central compartment and thus reflective of tissue propofol concentrations.     

丙泊酚和七氟醚对耳鼻咽喉手术患者一氧化氮代谢影响的比较

目的 观察丙泊酚和七氟醚麻醉耳鼻咽喉手术患者红细胞和血清中一氧化氮(NO)、亚硝酸盐(NO2-)、硝酸盐(NO3-)含量的变化.方法 18例择期行耳鼻咽喉手术患者,男13例,女5例,年龄18～52岁,体重51～100 kg,随机均分为丙泊酚(P组)和七氟醚(S组),麻醉诱导P组采用咪达唑仑0.06 mg/kg、舒芬太尼0.5μg/kg、丙泊酚2 mg/kg、阿曲库铵0.15 mg/kg,S组采用吸入浓度3％～5％的七氟醚,余同P组.麻醉维持P组泵注丙泊酚6～8 mg·kg-1·h-1和瑞芬太尼0.05～0.10μg·kg-1·min-1,S组泵注等量的瑞芬太尼和吸入挥发罐浓度为1.5％～2.0％的七氟醚.检测诱导前和麻醉后2h血清和红细胞中NO、NO2-、NO3-和黄嘌呤氧化酶(XOD)的浓度及变化.结果 与诱导前比较,P组和S组麻醉后2h红细胞NO和XOD浓度明显升高(P＜0.05),同时NO3-和NO2-浓度明显降低(P＜0.05),血清中NO、NO2-和NO3-水平均明显降低(P＜0.05),XOD水平均明显增加(P＜0.05).与P组比较,S组麻醉后2h血清中NO、NO3-水平明显降低(P＜0.05).红细胞中,两组诱导前以及S组麻醉后2 hNO与XOD呈明显线性相关.结论 耳鼻咽喉手术全麻患者术中红细胞NO生成增加,丙泊酚比七氟醚影响显著;而血清NO降低,七氟醚比丙泊酚影响显著,其机制可能与XOD的增加有关.     

对比七氟醚喉罩吸入麻醉与异丙酚静脉麻醉在小儿腹股沟斜疝手术中的应用

目的对比七氟醚喉罩吸入麻醉与异丙酚静脉麻醉在小儿腹股沟斜疝手术中的应用。 方法选取2017年1月至2018年1月,东部战区总医院收治的小儿腹股沟斜疝患儿100例,按麻醉方案的不同将其分为对照组和观察组,每组50例。对照组给予异丙酚静脉麻醉,观察组给予七氟醚喉罩吸入麻醉。比较2组麻醉效果,不同时间点的平均动脉压（MAP）、心率（HR）和血氧饱和度（SpO₂）的变化及2组拔管后不良反应。 结果观察组的意识消失时间、诱导至插管时间、苏醒时间、拔喉罩时间、离开麻醉恢复室时间均短于对照组,差异有统计学意义（P<0.05）。T1～T3时2组MAP和对照组HR比较,差异有统计学意义（P<0.05）,T1～T3时2组MAP和HR均呈现升高趋势（P<0.05）,且T2、T3时对照组MAP和HR高于观察组（P<0.05）;2组SpO₂在T1～T3无差异（P>0.05）;观察组和对照组苏醒后的不良反应发生率分别为4.00%、16.00%,且观察组的不良反应发生率低于对照组（P<0.05）。 结论小儿腹股沟斜疝手术中七氟醚喉罩吸入麻醉可以使患儿生命体征平稳,术后不良反应较少,且麻醉效果优于异丙酚静脉麻醉。     

Comparison of induction time and characteristics between sevoflurane and sevoflurane / nitrous oxide

A previous investigation using nitrous oxide with 5% enflurane (3.8 MAC) for single breath induction produced a stage of excitement which may be related to the difference in blood/gas coefficient solubility of these agents. The closer blood/gas solubility coefficient of sevoflurane and nitrous oxide may eliminate this phenomenon. We therefore evaluated 40 volunteers in a randomized study using 7.5% sevoflurane (3.7 MAC) in oxygen (n=21) or sevoflurane with nitrous oxide (n=19) using a single breath induction technique. Sevoflurane in nitrous oxide and oxygen reduced induction time by 15% compared to sevoflurane in oxygen alone (41 ±16 and 48±16 sec (s.d.), respectively). This was, however, not statistically significant. There were scarcely induction-related complications, such as coughing, laryngospasm, breath-holding, movements of a limb and excessive salivation, in either group. Thus, the addition of nitrous oxide neither increased the number of complications, nor the speed of induction.     

Single-breath induction of anesthesia: comparison of enflurane and sevoflurane

In this study induction of anesthesia using the single-breath technique with either enflurane or sevoflurane in oxygen was compared. Each group consisted of 16 unpremedicated volunteers who breathed approximately 1.7 minimum alveolar concentration (MAC) equivalents of either vapor. There were no significant differences in the cardiovascular and respiratory variables monitored. The induction of anesthesia with enflurane (141±41 s) required significantly more time than with sevoflurane (118±25 s). The enflurane group was associated with significantly more problems during induction, and showed moderate or sometimes severe excitatory movements of the extremities and/or coughing. Subjects in the enflurane group described the induction of anesthesia as less pleasant than in the sevoflurane group. We concluded that enflurane was less suitable for single-breath induction of anesthesia compared with sevoflurane.     

Comparison of adjuvant anesthetics for propofol induction

Purpose.Fentanyl was compared with nitrous oxide/sevoflurane as an adjuvant anesthesia to propofol during induction.Methods.Two-hundred sixty-three patients of American Society of Anesthesiologists physical status 1 or 2 undergoing minor surgery were randomly divided into two groups. Group F patients (n = 125) received 2g·kg^–1 fentanyl and 1.8mg·kg^–1 propofol, and were ventilated by mask with oxygen. Group S patients (n = 138) received 1.8mg·kg^–1 propofol, followed by inhalation of 4% sevoflurane in N₂O (4l·min^–1) and oxygen (2l·min^–1) by mask. The trachea was intubated exactly 2, 3, 4, or 5min after injection of 0.1mg·kg^–1 vecuronium, and the conditions of endotracheal intubation were scored according to the patients' responses to laryngoscopy and endotracheal intubation. Systolic blood pressure (SBP) and heart rate (HR) were measured before and after endotracheal intubation. The cost of anesthetics was also calculated.Results.No significant differences in SBP were observed between the groups throughout the induction period. HR did not change from preanesthetic values in group F. In contrast, HR in group S patients increased by 9–18 beats·min^–1 (bpm) after inhalation of N₂O/sevoflurane and further increased by 17–21bpm following endotracheal intubation. Significant differences in HR were noticed between the groups (P 0.001). The conditions of endotracheal intubation were similar in the two groups and were satisfactory when mask ventilation exceeded 3min. Fentanyl was less expensive than sevoflurane/N₂O anesthesia when mask ventilation exceeded 3min.Conclusion.From the standpoints of hemodynamics and drug cost, fentanyl is preferable to N₂O/sevoflurane inhalation as an adjuvant to propofol during induction, because mask ventilation for more than 3min was required for satisfactory endotracheal intubation.