Comparative effects of propofol, landiolol, and nicardipine on hemodynamic and bispectral index responses to endotracheal intubation: a prospective, randomized, double-blinded study

STUDY OBJECTIVES: To examine the comparative effects of propofol, landiolol, and nicardipine on hemodynamic responses and bispectral index (BIS) changes to endotracheal intubation. SETTING: Operating room of a university-affiliated general hospital. PATIENTS: 27 ASA physical status I and II patients who were scheduled to undergo elective general surgical, urological, or gynecological procedures with general anesthesia. STUDY DESIGN: Prospective, randomized, double-blinded study. INTERVENTIONS: Patients were divided into three groups as follows: Group 1 received propofol, 1 mg/kg; Group 2 received landiolol, 0.1 mg/kg; and Group 3 received nicardipine, 1 mg. After baseline measurements were recorded, anesthesia was induced with propofol, fentanyl, and vecuronium. Patients' lungs were ventilated with 100% oxygen for 120 seconds, at which time one of one of the study drugs was administered. Laryngoscopy and tracheal intubation were performed 4 minutes after anesthetic induction. MEASUREMENTS: Cardiac index (CI) and stroke volume index (SVI) were monitored continuously. Bispectral index was also monitored continuously from 5 minutes after tracheal intubation. MAIN RESULTS: Heart rate values in Group 3 increased 30 seconds after intubation; this increase lasted for 1 minute after intubation. Systolic blood pressure in all three groups decreased after induction of anesthesia and before tracheal intubation, and values returned closer to baseline values 30 seconds after intubation. In the propofol group, CI and SVI decreased after administration of additional propofol, lasting for 30 seconds after intubation. The BIS values rapidly decreased after induction of anesthesia, with no intergroup differences noted in BIS values (propofol group, 39+/-7; landiolol group, 44+/-14; nicardipine group, 41+/-9). However, BIS was significantly lower in the propofol group than in the other two groups from 30 seconds to 5 minutes after intubation. CONCLUSIONS: Landiolol, 0.1 mg/kg, before intubation provides effective hemodynamic stability in the postintubation period.     

瑞芬太尼复合丙泊酚联合无正压通气诱导技术在5分钟剖宫产中的应用

目的观察瑞芬太尼复合丙泊酚行无正压通气诱导在5分钟剖宫产中对产妇血流动力学及新生儿Apgar评分的影响。方法选择2014年8月至2016年1月,我院启动5 min剖宫产产妇60例,年龄23~38岁,体重55~80 kg,孕周38~40周。随机分为两组:瑞芬太尼1μg/kg复合丙泊酚2 mg/kg组(R组)和氯胺酮0.5 mg/kg复合丙泊酚2 mg/kg组(L组),每组30例。记录麻醉诱导插管(T1)、切皮(T2)、胎儿取出断脐时(T3)产妇SBP、DBP、HR及不良反应发生情况;记录胎儿娩出时间及胎儿娩出时脐动脉血气,以及新生儿1 min和5 min的Apgar评分。结果 T1、T2时L组SBP、DBP明显高于R组,HR明显快于R组(P0.05),T3时两组HR、SBP、DBP差异无统计学意义。两组脐动脉血气分析差异无统计学意义。两组胎儿娩出时间,新生儿1 min和5 min的Apgar评分差异均无统计学意义。结论瑞芬太尼复合丙泊酚联合无正压通气诱导技术在5分钟全麻剖宫产中产妇血流动力学波动轻微,不增加胎儿/新生儿呼吸抑制的风险,可行性好,对母婴安全可靠。     

The effect of propofol/remifentanil rapid-induction technique without muscle relaxants on intraocular pressure

Study ObjectiveTo evaluate the effect of propofol (two mg/kg)/remifentanil (4 μg/kg) on intraocular pressure (IOP) when used for rapid-sequence induction.DesignRandomized, double-blinded trial.SettingAmbulatory surgery center.Patients47 adult, ASA physical status I and II patients (ages 18-75 yrs), undergoing outpatient, elective, nonophthalmologic surgery.InterventionsAfter premedication with midazolam (two mg) and glycopyrrolate (0.2 mg), standard monitors and a bispectral index (BIS) monitor were applied. Patients underwent rapid-sequence induction with intravenous (IV) propofol two mg/kg and either remifentanil 4 μg/kg IV or succinylcholine 1.5 mg/kg IV. An experienced anesthesiologist, blinded to patient group assignment, performed intubation after 60 seconds.MeasurementsIOP, heart rate (HR), blood pressure, BIS scores, intubating conditions, and response to intubation (coughing or moving) were recorded at baseline, immediately after completion of induction, one minute after intubation, and three minutes after intubation. Time to return of spontaneous ventilation was also measured.Main ResultsRemifentanil produced a 39% decrease in IOP immediately after induction, which remained unchanged by laryngoscopy and intubation (P < 0.001). IOP remained below baseline even in patients who coughed or moved in response to intubation. Remifentanil caused a significant decrease in mean arterial pressure of 24% to 31% but no significant change in HR, and it blocked the hemodynamic response to laryngoscopy and intubation while providing intubating conditions comparable to those of succinylcholine.ConclusionsPropofol/remifentanil induction provides adequate intubating conditions, prevents an increase in IOP, and controls the hemodynamic stress response to laryngoscopy and intubation.     

Le landiolol diminue la tachycardie en réponse à l’intubation endotrachéale sans affecter la tension artérielle

PURPOSE: Beta-adrenergic receptor antagonists (beta-antagonists) have long been used to control perioperative tachyarrhythmias. The effects of a beta(1)-antagonist, landiolol, on perioperative hemodynamics are unknown. We aimed to determine the appropriate dosage of landiolol for the treatment of hemodynamic changes in response to endotracheal intubation. METHODS: Sixty-four patients without heart disease or hypertension, were assigned to receive saline (group C) or landiolol (0.1 or 0.3 mg.kg(-1); groups L1 and L3). Anesthesia was induced with propofol (2 mg.kg(-1) iv) followed by saline or landiolol iv. After ventilation with facemask using 2% sevoflurane in 100% oxygen for 90 sec, endotracheal intubation was performed. After intubation, anesthesia was maintained using 1% sevoflurane in combination with 50% nitrous oxide. Values of heart rate and mean arterial blood pressure were recorded before induction to five minutes after intubation. RESULTS: In group C, heart rate and mean blood pressure increased simultaneously after tracheal intubation, compared with baseline values. Heart rate values were attenuated immediately before as well as after intubation in group L3, compared with groups C and L1. Heart rate did not increase after tracheal intubation in group L1, compared with baseline. In contrast, mean arterial blood pressure values did not differ among groups. CONCLUSIONS: The newly developed beta(1)-antagonist landiolol (0.1 and 0.3 mg.kg(-1)) may help prevent tachycardia without affecting blood pressure during the induction of anesthesia.     

瑞芬太尼复合异丙酚麻醉诱导对气管插管条件及血流动力学的影响

目的对比不使用肌松剂的情况下,瑞芬太尼或芬太尼复合异丙酚麻醉诱导后对气管插管条件及血流动力学的影响。方法60名病人分为2组,诱导后2rain行气管插管术。分别记录诱导前、诱导后lmin及插管后2min的平均动脉压（MAP）和心率（Ha）。插管条件由操作者给予评分。结果两组插管成功率均为100％。瑞芬太尼组插管条件满意率80％,芬太尼73％。两组诱导后MAP和HR值较基础值均下降（P〈0．05）。插管后两组间的MAP值差异有统计学意义（P（0．05）。结论瑞芬太尼复合异丙酚麻醉诱导取得了同芬太尼复合异丙酚麻醉诱导一样良好的插管条件,在抑制插管引起的心血管反应方面瑞芬太尼组优于芬太尼组。     

The use of remifentanil to facilitate the insertion of the laryngeal mask airway

Propofol is often used as an IV induction drug for anesthesia and the insertion of a laryngeal mask airway (LMA). As a sole anesthetic, it may be associated with undesirable airway responses such as coughing and gagging. We conducted a randomized, double-blinded study to compare the conditions during insertion of the LMA in 120 patients who received normal saline (Group P), remifentanil 0.25 microg/kg (Group R1), or remifentanil 0.5 microg/kg (Group R2) before the induction of anesthesia with IV propofol. The addition of remifentanil significantly improved the conditions of insertion; in Group R1, 82.5% (33 of 40 patients), and in Group R2, 85.0% (34 of 40 patients) had excellent insertion conditions as compared with the Control group P, 32.5% (13 of 40 patients). Patients in Group P were apneic for a mean (SD) time of 85 (38) s, 186 (75) s in group R1, and 284 (130) s in group R2. There was a lesser decrease in mean arterial blood pressure in group R1. We conclude that remifentanil 0.25 microg/kg, when administered after IV propofol 2.5 mg/kg, provides excellent conditions for insertion of the LMA with minimal hemodynamic disturbances. IMPLICATIONS: Small-dose remifentanil can provide excellent conditions for laryngeal mask airway insertion with minimal hemodynamic disturbances.     

丙泊酚对颅内手术麻醉诱导期脑脊液压力的影响

目的　观察丙泊酚对颅内手术病人麻醉诱导时脑脊液压力 (CSFP)、脑灌注压 (CPP)、MAP和HR的影响 ,探讨其在神经外科麻醉中的应用价值。方法　 2 0例ASAⅠ～Ⅱ级颞叶肿瘤择期手术病人 ,入室后行L3～ 4蛛网膜下隙穿刺置管监测CSFP。麻醉诱导气管内插管后 ,吸入异氟醚维持。持续监测并记录麻醉诱导中、静注芬太尼 2 μg/kg和咪唑安定 0 0 4～ 0 0 5mg/kg、静注丙泊酚2mg/kg后 2分钟、5分钟及追加丙泊酚 1mg/kg后 2分钟、5分钟和 10分钟的CSFP、MAP、HR、SpO2 、PETCO2 。结果　静注丙泊酚 2mg/kg 2分钟后CSFP较麻醉前显著下降 (P <0 0 5 ) ,5分钟和追加丙泊酚 1mg/kg后 2分钟 (气管插管时 )、5分钟时CSFP较麻醉前下降更为显著 (P <0 0 1)。MAP在静注丙泊酚 2mg/kg后 2分钟、5分钟和追加丙泊酚 1mg/kg后 2分钟、5分钟都较麻醉前明显下降 (P <0 0 5和P <0 0 1)。CPP在静注丙泊酚 2mg/kg后 2分钟和 5分钟均较麻醉前显著下降(P <0 0 1和P <0 0 5 )。HR在静注丙泊酚后较麻醉前仅有轻度降低。结论　静注丙泊酚能降低CSFP、MAP和CPP ,抑制插管反应 ,其程度与剂量相关 ,丙泊酚是颅内手术麻醉的较好选择。     

Effect of ephedrine on the onset time of succinylcholine

BACKGROUND: The aim of this study was to evaluate the effect of ephedrine administered prior to induction of anaesthesia on the onset time of succinylcholine for endotracheal intubation. METHODS: Patients were randomly assigned to receive intravenously (i.v.) either 70 microg kg(-1) of ephedrine (Group I; n = 25) or saline (Group II; n = 25) 3 min before induction of anaesthesia. Induction of anaesthesia was provided with propofol 2 mg kg(-1) plus remifentanil 1 microg kg(-1). Onset time and duration of muscle fasciculation and onset time of succinylcholine were recorded. Intubation was attempted after establishment of 100% thumb relaxation and difficulties were recorded. Heart rate, pulse oxymetry (SpO2) and mean arterial pressure (MAP) were also recorded. RESULTS: The onset time of succinylcholine were significantly (P < 0.001) shorter in Group I (26 +/- 4 s), when compared with Group II (43 +/- 6 s). Patients in Group I were intubated at 49 +/- 7 s compared with 68 +/- 10 s in Group II. The score of intubation was similar in both groups. Duration of muscle fasciculation was longer in Group II. Heart rate and MAP increased significantly (P < 0.05) after ephedrine injection, compared with the baseline value in Group I. CONCLUSIONS: The onset time of succinylcholine can be shortened with ephedrine pretreatment.     

Comparison of propofol-alfentanil and propofol-remifentanil anaesthesia in percutaneous nephrolithotripsy

BACKGROUND AND OBJECTIVE: Percutaneous nephrolithotripsy (PCNL) is used for the fragmentation and removal of stones from the renal pelvis and renal calyceal systems. We compared the effects of propofol-alfentanil or propofol-remifentanil anaesthesia on haemodynamics, recovery characteristics and postoperative analgesic requirements during percutaneous nephrolithotripsy. METHODS: Thirty non-premedicated patients were randomly allocated to receive either propofol-alfentanil (Group A) or propofol-remifentanil (Group R). The loading dose of the study drug was administered over 60 s (alfentanil 10 microg kg(-1) or remifentanil 1 microg kg(-1)) followed by a continuous infusion (alfentanil 15 microg kg(-1) h(-1) or remifentanil 0.15 microg kg(-1) min(-1)). Propofol was administered until loss of consciousness and maintained with a continuous infusion of 75 microg kg(-1) min(-1) in both groups. Atracurium was given for endotracheal intubation at a dose of 0.5 mg kg(-1) and maintained with a continuous infusion of 0.4 mg kg(-1) h(-1). Mean arterial pressure heart rate, the total amount of propofol, time of recovery of spontaneous ventilation, extubation and eye opening in response to verbal stimulus and analgesic requirement were recorded. RESULTS: In Group A, mean arterial pressure was higher at the first minute in the prone position, and during skin incision and lithotripsy, and heart rate was higher during skin incision and lithotripsy when compared with Group R (P < 0.05). The total amount of propofol did not differ between groups. Time of recovery of spontaneous ventilation, extubation and eye opening were significantly shorter in Group R than Group A (P < 0.05). CONCLUSIONS: Both propofol-remifentanil and propofol-alfentanil anaesthesia provided stable haemodynamics during percutaneous nephrolithotripsy, whereas propofol-remifentanil allowed earlier extubation.     

The effects of remifentanil and alfentanil-based total intravenous anesthesia (TIVA) on the endocrine response to abdominal hysterectomy

STUDY OBJECTIVE: To compare the effects of remifentanil with alfentanil as a part of total intravenous anesthesia (TIVA) on plasma concentrations of cortisol, insulin, and glucose, and hemodynamic responses in patients undergoing abdominal hysterectomy. DESIGN: Randomized, double-blind study. SETTING: University hospital. PATIENTS: 24 ASA physical status I female patients scheduled for abdominal hysterectomy. INTERVENTIONS: Premedicated patients were randomly allocated to receive either remifentanil-propofol (Group R) or alfentanil-propofol (Group A). The loading dose of the study drug was administered over 60 seconds (remifentanil l microg kg(-l) or alfentanil 10 microg kg(-l)) followed by a continuous infusion (remifentanil 0.2 microg kg(-l) min(-l) or alfentanil 0.5 microg kg(-l) min(-l)). In both groups, propofol was administered until loss of consciousness and maintained with a propofol infusion rate of 100 microg kg(-l) min(-l). After induction of anesthesia, all patients were manually ventilated by mask with O2-air mixture for 20 minutes. Then rocuronium 0.6 mg kg(-l) was given for tracheal intubation. MEASUREMENTS: Mean arterial pressure (MAP) and heart rate (HR) were recorded. Plasma concentrations of cortisol, insulin, and glucose were measured during anesthesia and in the recovery room. MAIN RESULTS: In Group R, MAP and HR were lower after tracheal intubation and skin incision than in Group A (p < 0.05). Plasma cortisol concentrations decreased from baseline values at 20 minutes after induction, after tracheal intubation, and skin incision in Group R (p < 0.001). Plasma concentrations of cortisol and glucose increased from baseline values at 30 minutes after skin incision and continued to increase in both groups (p = 0.001). Plasma concentrations of cortisol, insulin, and glucose did not differ between groups at all sampling times. CONCLUSION: Remifentanil provided better hemodynamic stability than alfentanil during anesthesia and surgery. However, both remifentanil and alfentanil had similar effects on the stress endocrine response to abdominal hysterectomy.     

Propofol and remifentanil for intubation without muscle relaxant: the effect of the order of injection

BACKGROUND: Common practice in intubation without muscle relaxant is to inject the opioid drug prior to the hypnotic drug. Because remifentanil reaches adequate cerebral concentration more rapidly than does propofol, we tested the hypothesis that injection of remifentanil after propofol might lead to better intubating conditions. METHODS: Thirty ASA I-II patients scheduled for elective surgery and with no anticipated difficult intubation were enrolled in the study. Five minutes after midazolam 30 microg kg(-1), patients were randomized into two groups: group PR received propofol 2.5 mg kg(-1) followed by remifentanil 1 microg kg(-1), and group RP received remifentanil 1 microg kg(-1) followed by propofol 2.5 mg kg(-1). Intubating conditions were compared using a well-validated score, and continuous arterial pressure was recorded non-invasively. RESULTS: Compared with group RP, intubating conditions were significantly better in group PR. The mean arterial pressure decrease was more pronounced in group RP. CONCLUSIONS: We therefore conclude that in premedicated healthy patients with no anticipated risk of difficult intubation, intubating and haemodynamic conditions are better when remifentanil is injected after propofol.     

Propofol is superior to thiopental for intubation without muscle relaxants

PURPOSE: To compare intubating conditions and cardiovascular changes following induction of anesthesia and tracheal intubation in patients receiving either lidocaine-remifentanil-propofol or lidocaine-remifentanil-thiopental prior to induction. METHODS: In a randomized, double-blind study 76 healthy adult patients were assigned to one of two groups: lidocaine 1.5 mg.kg(-1), remifentanil 2 mug.kg(-1) and propofol 2 mg.kg(-1) (Group P) or lidocaine 1.5 mg.kg(-1), remifentanil 2 mug.kg(-1) and thiopental 5 mg.kg(-1) (Group T). Ninety seconds after the administration of the hypnotic agent, laryngoscopy and tracheal intubation were attempted. Intubating conditions were assessed as excellent, good or poor on the basis of ease of ventilation, jaw relaxation, position of the vocal cords, and patient's response to intubation and slow inflation of the tracheal cuff. The mean arterial pressure (MAP) and heart rate (HR) were measured 45 sec after hypnotic agent administration, immediately after tracheal intubation, two and five minutes after intubation. RESULTS: Excellent intubating conditions were obtained in 84% of Group P patients and 50% of Group T patients (P < 0.05). The percentage decrease from baseline MAP was significantly higher in Group P than in Group T postinduction (27.4% +/- 11.6 vs 21.8% +/- 10.0) and immediately postintubation (19.0% +/- 16.7 vs 11.2% +/- 14.9). The percentage change from baseline HR was significantly higher in Group P than in Group T postinduction (13.8% +/- 9.7 vs 0.5% +/- 12.4), immediately postintubation (8.7% +/- 13.7 vs 2.1% +/- 13.1), and two minutes postintubation (7.04% +/- 14.3 vs 3.5% +/- 14.3). CONCLUSION: Lidocaine-remifentanil-propofol is superior to lidocaine-remifentanil-thiopental for tracheal intubation without muscle relaxants. However, it induces more hypotension and bradycardia.     

瑞芬太尼复合艾司洛尔对全麻患者气管插管时心血管指标的影响

目的 评价瑞芬太尼复合艾司洛尔对全麻患者气管插管时心血管系统的影响.方法 选择择期上腹部手术患者60 例,ASAⅠ - Ⅱ级,随机分为3 组（n = 20）：瑞芬太尼2 μg/kg组（Ⅰ组）,芬太尼4 μg/kg ＋ 艾司洛尔1 mg/kg 组（Ⅱ组）和瑞芬太尼2 μg/kg ＋ 艾司洛尔1 mg/kg组（Ⅲ组）.分别注入上述药物、丙泊酚2 mg/kg 和阿曲库铵1.5 mg/kg 后行气管插管,机械通气.记录麻醉诱导前（T1）、麻醉诱导后1 min（T2）、气管插管后即刻（T3）、气管插管后1 min（T4）、3 min（T5）及10 min（T6）的HR、收缩压（SP）、舒张压（DP）,并于T1、T2、T4 时分别采集桡动脉血7 ml,测定血浆肾上腺素（Ad）和去甲肾上腺素（NA）的浓度.结果 与Ⅰ组比较,Ⅱ组和Ⅲ组HR、SP、DP 及血浆Ad 和NA 的浓度降低（P 〈 0.05）;与Ⅱ组比较,Ⅲ组HR、SP、DP 降低（P 〈 0.05）;与T1 比较,T2时3 组HR、SP、DP 及血浆Ad 和NA 的浓度降低（P 〈 0.05）;Ⅰ组T3 时HR、SP、DP 升高,Ⅱ组和Ⅲ组差异无统计学意义.结论 瑞芬太尼复合艾司洛尔可更好地预防全麻患者气管插管时的心血管副作用.     

A comparative study between the effects of 4% endotracheal tube cuff lignocaine and 1.5 mg/kg intravenous lignocaine on coughing and hemodynamics during extubation in neurosurgical patients: a randomized controlled double-blind trial

A prospective, randomized double-blind trial was performed to compare the effects of 4% endotracheal tube cuff lignocaine and 1.5 mg/kg intravenous (IV) lignocaine on coughing and hemodynamics during extubation in patients undergoing elective craniotomies in supine position. Forty-one patients received 4% lignocaine into the endotracheal tube cuff after intubation (ETT group) and 41 patients received IV lignocaine at 1.5 mg/kg before extubation (IV group). Coughing was assessed by a scale of 3 at the time of extubation. Hemodynamic parameters recorded at 1-minute interval after extubation for 5 minutes were compared with the baseline values recorded before skin closure. Results showed that there was no significant difference between the groups in terms of coughing or the hemodynamic response to tracheal extubation. In conclusion, 4% endotracheal tube cuff lignocaine was not superior to 1.5 mg/kg IV lignocaine in attenuating coughing and hemodynamic changes during extubation.     

Comparison of effects of remifentanil, alfentanil and fentanyl on cardiovascular responses to tracheal intubation in morbidly obese patients

BACKGROUND AND OBJECTIVE: The effects of remifentanil, alfentanil and fentanyl were compared on cardiovascular responses to laryngoscopy and endotracheal intubation in morbidly obese patients. METHODS: Eighty morbidly obese ASA I-II patients were included in the study. Patients were randomly divided into four groups to receive either 1 microgkg(-1) fentanyl (Group F), 10 microgkg(-1) alfentanil (A), 1 microgkg(-1) followed by an infusion of 0.5 pg kg min(-1) remifentanil (R) or saline (P). The patients corrected weight was used to calculate the drug doses. Body mass indices (range) were: 54.3 +/- 7.37 (49-78.4), 55.67 +/- 7.44 (48.5-78.4), 53.17 +/- 5.36 (48.1-63.2), and 56.3 +/- 6.09 (46.6-67.7) kg m(-2), in Groups F, R, A and P respectively. Systolic, diastolic and mean arterial pressures and heart rate were measured non-invasively at three time points, which were 2 min before induction, 2 min after induction and 2 min after endotracheal intubation. RESULTS: After induction of anaesthesia, arterial pressures decreased significantly in all groups, but the decrease was more pronounced in Groups A and R. After induction, heart rate decreased significantly in all groups except in Group P. After intubation, haemodynamic responses were similar in the remifentanil, fentanyl and alfentanil groups and were within normal limits. In Group P, arterial pressures and heart rates were significantly higher. CONCLUSIONS: Alfentanil, fentanyl and remifentanil in the doses described had similar effects in controlling the haemodynamic response to tracheal intubation in ASA I-II morbidly obese patients.     

Effects of remifentanil and fentanyl on intraocular pressure during the maintenance and recovery of anaesthesia in patients undergoing non-ophthalmic surgery

BACKGROUND AND OBJECTIVE: To compare the effects of remifentanil and fentanyl on intraocular pressure during the maintenance and recovery of anaesthesia in patients undergoing elective non-ophthalmic surgery. METHODS: Thirty-two patients (ASA I-II) were randomized into two groups to receive either a continuous infusion of remifentanil (0.25-0.5 microg kg(-1) min(-1), n =16, Group R) or an intermittent bolus of fentanyl (2-5 microg kg(-1), n = 16, Group F) during the maintenance of anaesthesia. For the induction of anaesthesia, Group R received remifentanil 1 microg kg(-1) and Group F received fentanyl 2 microg kg(-1); both groups then received propofol 2 mg kg(-1) with vecuronium 0.1 mg kg(-1). Anaesthesia in both groups was maintained with a continuous infusion of propofol 4-8 mg kg(-1) h(-1). Ventilation of the lungs was controlled to a constant end-tidal PCO2 of 4.7-5.4 kPa. Blood pressure, electrocardiography, heart rate and oxygen saturation were monitored throughout anaesthesia. Intraocular pressure was determined before surgery, during the maintenance of anaesthesia, 2 min after emergence and in the recovery room using a Perkins hand-held applanation tonometer by an ophthalmologist blinded to the anaesthetic technique. RESULTS: After induction of anaesthesia, a significant decrease in intraocular pressure in the remifentanil group from 13.6 +/- 2.6 to 7.1 +/- 3.1 mmHg (P < 0.001) and in the fentanyl group from 13.7 +/- 2.2 to 9.7 +/- 3.4 mmHg (P < 0.001) was observed and maintained during anaesthesia. Thirty minutes after the end of anaesthesia, intraocular pressure returned to baseline values in both groups (remifentanil: 13.9 +/- 2.8 mmHg, P = 0.28; fentanyl: 13.6 +/- 2.3 mmHg, P = 0.59). The intraocular pressure and haemodynamic variables did not differ significantly between the two groups (intraocular pressure, P = 0.7327; blood pressure, P = 0.1295; heart rate, P = 0.8601). CONCLUSIONS: Remifentanil maintains intraocular pressure at an equally reduced level compared with fentanyl.     

Minimal effective dose of magnesium sulfate for attenuation of intubation response in hypertensive patients

Study ObjectiveTo study the minimal effective dose of magnesium sulfate to control blood pressure (BP) during intubation in hypertensive patients.DesignProspective, randomized, double-blind study.SettingOperating room of an academic medical center.Patients80 adult, ASA physical status 1 and 2, controlled hypertensive patients undergoing elective surgery under general anesthesia and requiring endotracheal intubation.InterventionsPatients were randomized to 4 groups. Patients in study groups received a magnesium sulfate infusion at a dose of 30 (Group I), 40 (Group II), or 50 mg/kg (Group III) before induction of anesthesia, while patients in control group (Group IV) received a 1.5 mg/kg lidocaine bolus 90 seconds before intubation. Anesthesia was induced and maintained with a propofol infusion. Laryngoscopy and intubation were performed 4 minutes after administration of vecuronium.MeasurementsHeart rate (HR) and BP were recorded before, during, and after endotracheal intubation for10 minutes. Measures to manage hemodynamic instability were recorded. Serum magnesium levels were also recorded.Main ResultsThe changes in HR were comparable among groups. Mean arterial pressure (MAP) was maintained within normal limits in Group I patients while Groups II and III patients showed a significant decrease in MAP (P = 0.01) compared with baseline. A total of 6 patients (30%) in Group II and 10 patients (50%) in Group III required interventions (P = 0.001). No patient in Group I and only one patient (5%) in Group IV required intervention.ConclusionsMagnesium 30 mg/kg is the optimum dose to control BP during intubation in hypertensive patients. A further increase in the dose of magnesium may cause significant hypotension.     

Assessment of intubating conditions in adults after induction with propofol and varying doses of remifentanil

We have assessed intubating conditions in three groups of 60 ASA I or II patients after induction of anaesthesia with propofol 2 mg kg-1 and remifentanil 0.5, 1.0 or 2.0 micrograms kg-1. Tracheal intubation was graded according to ease of laryn-goscopy, position of the vocal cords, coughing, jaw relaxation and movement of the limbs. Intubation was successful in 80%, 90% and 100% of patients after remifentanil 0.5, 1.0 or 2.0 micrograms kg-1, respectively. Overall intubating conditions were regarded as acceptable in 20%, 50% and 80% of patients, respectively. All three groups had a decrease in arterial pressure after induction but there was no difference between groups. The decrease in arterial pressure was not regarded as clinically significant. Intubating conditions were best after induction with remifentanil 2 micrograms kg and propofol 2 mg kg-1.      

Intraocular pressure more reduced during anesthesia with propofol than with sevoflurane: both combined with remifentanil

BACKGROUND: Short-acting anesthetic agents are suitable and commonly used in ocular surgery. Propofol and remifentanil are known to reduce intraocular pressure (IOP), but no information is available regarding the effects of sevoflurane combined with remifentanil on IOP. METHODS: Therefore, a prospective, randomized study was conducted to compare the effects on IOP of two different anesthetic techniques: one based on a total intravenous anesthesia with propofol (Group P, bolus 1.5-2.0 mg/kg, maintenance 3.0-7.0 mg/kg/h); and the other based on sevoflurane (Group S, inhalational induction, end-tidal concentration 0.7-1.2 vol.%). An infusion of remifentanil (10 microg/kg/h) was used with both techniques. In ASA I-III patients with normal IOP undergoing elective cataract surgery, using an applanation tonometer, IOP was measured contralateral to the operated eye at nine predefined time points before, during and after anesthesia. RESULTS: The two groups (n=20 each) were comparable with regard to demographic data and hemodynamic variables. Baseline IOP was 14.2+/-2.8 mmHg (Group P) and 14.1+/-2.4 mmHg (Group S; NS). During and following the induction of anesthesia, IOP was reduced in both groups. Intraocular pressure was significantly lower in Group P (6.0+/-3.2 mmHg) than in Group S (8.9+/-3.4 mmHg) during the induction of anesthesia. CONCLUSION: In patients undergoing cataract surgery under general anesthesia with tracheal intubation, anesthetic regimens with propofol as well as with sevoflurane, both combined with remifentanil, decrease IOP significantly. The decrease in IOP was significantly more pronounced in the propofol group than in the sevoflurane group.     

A dose study of remifentanil in combination with propofol during tracheobronchial foreign body removal in children

Study ObjectiveTo assess the effect of two different remifentanil infusion doses on hemodynamic stability and recovery characteristics in children undergoing tracheobronchial foreign body removal during rigid bronchoscopy.DesignProspective, randomized, clinical comparison study.SettingOperating room of a university hospital.Patients70 ASA physical status 1 and 2 children, aged 3–12 years, presenting for tracheobronchial foreign body removal during rigid bronchoscopy.InterventionsChildren were divided equally into two groups to receive either a 0.1 μg/kg/min (Group R1) or 0.2 μg/kg/min (Group R2) remifentanil infusion. Ten minutes after the remifentanil infusion, 3 mg/kg of propofol and 0.02 mg/kg of atropine were given. Anesthesia was maintained with 0.1 μg/kg/min of remifentanil and 100–250 μg/kg/min of propofol in Group R1 and 0.2 μg/kg/min of remifentanil and 100–250 μg/kg/min of propofol in Group R2. After baseline measurements were recorded, 0.2 mg/kg of mivacurium was given intravenously. Ventilation was maintained with 100% O₂ via a “T” piece connected to the side arm of the bronchoscope.MeasurementsHeart rate (HR), systolic (SBP), diastolic (DBP) and mean arterial pressures (MAP), and O₂ saturation (SpO₂) were recorded before (baseline) and after induction, and 1, 3, 5, 10, 15, 20, 25, and 30 minutes after insertion of the rigid bronchoscope into the trachea. Emergence characteristics and complications were noted. Statistical analysis was performed using independent samples t-test, repeated measures, and chi-square test as appropriate.Main ResultsGroups were similar in demographics and duration of bronchoscopy and anesthesia (P > 0.05). In Group R1, HR, SBP, DBP, and MAP increased one minute after insertion of the bronchoscope in Group R1 (P < 0.01). Propofol consumption was significantly higher in Group R1 (63.6 ± 30.1 mg) than Group R2 (39.8 ± 26.6 mg; P < 0.01). Time to spontaneous eye opening was 8.6 ± 1.3 minutes in Group R1 and 6.3 ± 1.1 minutes in Group R2 (P < 0.05). The time to recovery to an Aldrete score of 9 was greater in Group R1 (19.8±3.0 min) than Group R2 (16.1±3.0 min; P < 0.01).ConclusionA remifentanil 0.2 μg/kg/min infusion with propofol provides hemodynamic stability and early recovery in children undergoing foreign body removal during rigid bronchoscopy.