End-tidal Sevoflurane Concentration Research Articles

Reduced sevoflurane consumption in cirrhotic compared to non-cirrhotic patients undergoing major hepatic surgery

BackgroundThere is evidence in literature that chronic hepatic patients need less anesthesia compared with healthy ones. Liver cirrhosis leads to a reduction in liver mass and hepatic blood flow with an effect on drug clearance and cardiovascular stability.AimTo evaluate sevoflurane consumption during entropy monitored general anesthesia in cirrhotic and non-cirrhotic patients during transition from consciousness to unconsciousness and throughout the procedure of major hepatic surgical procedures.Patients and methodsForty patients scheduled for major hepatic resection at the National Liver Institute, Menofiya University, Egypt, were studied prospectively and randomized into two equal groups. Group I (n. 20) cirrhotic patients (Child Pugh Grade A) with focal lesion, Group II (n. 20) healthy live liver donors undergoing major hepatectomies. Sevoflurane inhalational concentration was adjusted to achieve a state and response entropy of 40–60, and when RE increases 5–10 units above SE; more intravenous analgesics were given.ResultsMean (SD) Sevoflurane consumption in Group II showed higher consumption 23.5 (3.23) ml, compared to Group I 16 (2.19) ml. Mean (SD) sevoflurane consumption after 4 and 6 h from induction also showed a lower value in Group I 10.7(1.94), 9(1.22) ml, than in Group II 17.2(1.69), 14.1(2.19) ml, respectively. Mean (SD) end tidal sevoflurane concentration was lower in Group I 1.4(0.12) after 2 h from induction than in Group II 1.7(0.11). After 4 and 6 h from induction Group I demonstrated a lower value compared to Group II (P < 0.05.). Mean blood pressure, heart rate, urine output and CVP showed no significant changes during maintenance between the two groups.ConclusionThis study demonstrated that cirrhotic patients require less sevoflurane consumption and lower end-tidal concentration to maintain general anesthesia with entropy guidance. This could also have an important impact on the economic costs when applied on a larger scale.

Anesthetic Overdose Leading to Cardiac Arrest Diagnosed by End-Tidal Inhalant Concentration Analysis in a Dog

A 5-year-old male-castrated Cocker Spaniel presented to the Veterinary Teaching Hospital of the University of Georgia for a total ear canal ablation. Premedication was with carprofen 2.2 mg/kg SQ, hydromorphone 0.1 mg/kg IM, diazepam 0.2 mg/kg IM, and glycopyrrolate 0.01 mg/kg IM. The patient was induced with lidocaine 2 mg/kg IV and etomidate 1 mg/kg IV and maintained with sevoflurane and a constant rate infusion consisting of lidocaine 0.05 mg/kg/min. Before surgery start, the patient’s systolic arterial blood pressure was 110 mmHg, heart rate (HR) was 85 beats/min, respiratory rate was 8 breaths/min, end-tidal sevoflurane concentration was 3.2%, and end-tidal CO2(ETCO2) was 23 mmHg. As a scrub was being performed, the patient’s HR abruptly dropped to 20 beats/min over the course of 2 minutes. His ETCO2simultaneously decreased to 16 mmHg. At this time, cardiopulmonary arrest was diagnosed. After two minutes of resuscitation, a spontaneous heart beat was obtained and the patient was successfully recovered and discharged without further incident. The cardiac arrest in this case is most likely attributable to an overdose of inhalant anesthesia, which was diagnosed by an anesthetic inhalant concentration monitor. A gas analyzer may be a helpful contribution to the small animal practitioner, particularly those performing more lengthy or complex procedures.

Preanesthetic dexmedetomidine 1 µg/kg single infusion is a simple, easy, and economic adjuvant for general anesthesia

BackgroundDexmedetomidine is an α2-adrenoreceptor agonist with sedative, analgesic and anxiolytic effects, and it has more selective α2-adrenergic effect than clonidine. We evaluate the effect of preansethetic dexmedetomidine 1 µg/kg single infusion on sedation, hemodynamics, anesthetic consumption, and recovery profiles during anesthesia.MethodsForty-two female patients with American Society of Anesthesiologists physical status I or II undergoing gynecologic surgery with anticipated operation time of 2 h, were randomly assigned to receive dexmedetomidine 1 µg/kg (Dex group) or saline (control group) iv over 10 min before anesthetic induction. After tracheal intubation with propofol 2 mg/kg, cisatracurium 0.15 mg/kg iv, anesthesia was maintained with sevoflurane, O2 50%, N2O 50% around a BIS value of 40.ResultsAfter study drug infusion, BIS of Dex group was lower than that of control group (93.9 ± 3.1 vs 51.5 ± 5.2, P < 0.05). Mean arterial pressure (MAP) and heart rate (HR) after intubation were increased in control group, but did not change in Dex group. During maintenance, there was no difference in MAP between groups, but HR of Dex group was lower compared to that of control group. End-tidal concentration (2.0 ± 0.5 vol% vs 1.4 ± 0.3 vol%, P < 0.05) and total cumulative consumption of sevoflurane (34.6 ± 3.8 ml vs 26.5 ± 5.3 ml, P < 0.05) were lower in Dex group than in control group. Recovery profiles, modified Aldrete score, postoperative nausea vomiting, and visual analogue pain score were not significantly different between groups.ConclusionsPreanesthetic dexmetomidine 1 µg/kg single infusion is a simple, easy, and economic general anesthetic adjuvant that maintains stable hemodynamics and decrease anesthetic consumption without the change of recovery profiles.

Anesthetic requirements and stress hormone responses in chronic spinal cord-injured patients undergoing surgery below the level of injury: nitrous oxide vs remifentanil.

BackgroundNitrous oxide (N2O) and remifentanil both have anesthetic-reducing and antinociceptive effects. We aimed to determine the anesthetic requirements and stress hormone responses in spinal cord-injured (SCI) patients undergoing surgery under sevoflurane anesthesia with or without pharmacodynamically equivalent doses of N2O or remifentanil.MethodsForty-five chronic, complete SCI patients undergoing surgery below the level of injury were randomly allocated to receive sevoflurane alone (control, n = 15), or in combination with 67% N2O (n = 15) or target-controlled infusion of 1.37 ng/ml remifentanil (n = 15). Sevoflurane concentrations were titrated to maintain a Bispectral Index (BIS) value between 40 and 50. Measurements included end-tidal sevoflurane concentrations, mean arterial blood pressure (MAP), heart rate (HR), and plasma catecholamine and cortisol concentrations.ResultsDuring surgery, MAP, HR, and BIS did not differ among the groups. Sevoflurane concentrations were lower in the N2O group (0.94 ± 0.30%) and the remifentanil group (1.06 ± 0.29%) than in the control group (1.55 ± 0.34%) (P < 0.001, both). Plasma concentrations of norepinephrine remained unchanged compared to baseline values in each group, with no significant differences among groups throughout the study. Cortisol levels decreased during surgery as compared to baseline values, and returned to levels higher than baseline at 1 h after surgery (P < 0.05) without inter-group differences.ConclusionsRemifentanil (1.37 ng/ml) and N2O (67%) reduced the sevoflurane requirements similarly by 31-39%, with no significant differences in hemodynamic and neuroendocrine responses. Either remifentanil or N2O can be used as an anesthetic adjuvant during sevoflurane anesthesia in SCI patients undergoing surgery below the level of injury.

Minimal alveolar concentration of sevoflurane for maintaining bispectral index below 50 in morbidly obese patients

Morbid obesity is associated with important differences in pharmacokinetics and pharmacodynamics. The aim of this study was to determine minimum alveolar concentration of sevoflurane for maintaining bispectral index (BIS) below 50 (MACBIS50 ) in morbidly obese patients undergoing bariatric surgery using the Continual Reassessment Method (CRM) method. Twenty-four morbidly obese patients (body mass index 40-70 kg/m(2) ) were enrolled in our study. Twenty minutes following pre-medication with fentanyl 100 μg, general anaesthesia was induced using propofol 2 mg/kg and cisatracurium 2 mg/kg to facilitate tracheal intubation. The lowest BIS score was recorded following induction. Thereafter, when BIS began to increase > 60, maintenance of anaesthesia was started with a pre-determined end-tidal sevoflurane concentration (ET Sevo) and maintained for 10 min followed by 1-min assessment of BIS taken at 10-s intervals to determine the ET Sevo. The ET Sevo leading to a probability close to 80% success was calculated using the CRM, and the MACBIS50 leading to 50% success was calculated by fitting the data to a dose-probability sigmoid curve, respectively. The ET Sevo able to maintain BIS value below 50 was 1.8% in 67% [95% confidence interval (CI) 0.44-0.86] and higher in the remaining 33% of the patients and the ET Sevo leading to a BIS value below 50 in 50% of the patients (MACBIS50 ) was 1.6 ± 0.10%. The calculated values (1.8% and 1.6%) were higher than that previously reported in normal adult patients (0.97%; 95% CI 0.89-1.1%) and less than that reported in children (2.8%; 95% CI 2.7-3.1%).

Effect of systemic lidocaine infusion on train-of-four ratios during recovery from general anesthesia

IntroductionIn spite of introduction of intermediate-acting neuromuscular blocking drugs (NMBDs), incidence of postoperative residual muscle weakness is still high. The aim of this trial is to study the effect of systemic lidocaine infusion on intraoperative consumption of rocuronium and TOF ratios at extubation and on arrival to postanesthesia care unit (PACU).MethodsForty-six ASA I–III patients aged 16–60 yr were randomly allocated into two groups: lidocaine (L) group (n = 23) and control (C) group (n = 23). After induction of standard endotracheal general anesthesia with fentanyl, propofol and rocuronium, patients of group L were given i.v. lidocaine bolus (1.5 mg kg−1) followed by continuous infusion (1.5 mg kg−1 h−1) till time of endotracheal extubation while patients in group C were given equal volumes of normal saline. Rocuronium was titrated based on clinical signs. On conclusion of surgery, neostigmine was given to reverse the effects of rocuronium if TOF count was two or more. Immediately before extubation, TOF ratio was measured and recorded and considered the primary outcome.ResultsThere were no significant differences between the two study groups regarding intraoperative fentanyl doses or core temperature at the end of surgery. End-tidal sevoflurane concentrations were significantly lower in group L than in group P (P < 0.01). The dose of rocuronium was significantly less in group L than in group C (P = 0.001). Train-of four ratios were significantly higher in group L than in group C either before extubation (P < 0.001) or on arrival to PACU (P = 0.001).ConclusionThe current study shows that intraoperative use of i.v. lidocaine infusion in generally anesthetized patients can result in higher TOF ratios at time of extubation and on arrival to PACU when rocuronium was given based on clinical signs.

Determination of the minimum anesthetic concentration of sevoflurane in thick-billed parrots (Rhynchopsitta pachyrhyncha)

To determine the minimum anesthetic concentration (MAC) of sevoflurane in thick-billed parrots (Rhynchopsitta pachyrhyncha) and compare MAC obtained via mechanical and electrical stimulation. 15 healthy thick-billed parrots. Anesthesia was induced in each parrot by administration of sevoflurane in oxygen. An end-tidal sevoflurane concentration of 2.5% was established in the first bird. Fifteen minutes was allowed for equilibration. Then, 2 types of noxious stimulation (mechanical and electrical) were applied; stimuli were separated by 15 minutes. Responses to stimuli were graded as positive or negative. For a positive or negative response to a stimulus, the target end-tidal sevoflurane concentration of the subsequent bird was increased or decreased by 10%, respectively. The MAC was calculated as the mean end-tidal sevoflurane concentration during crossover events, defined as instances in which independent pairs of birds evaluated in succession had opposite responses. A quantal method was used to determine sevoflurane MAC. Physiologic variables and arterial blood gas values were also measured. Via quantal analysis, mean sevoflurane MAC in thick-billed parrots determined with mechanical stimulation was 2.35% (90% fiducial interval, 1.32% to 2.66%), which differed significantly from the mean sevoflurane MAC determined with electrical stimulation, which was 4.24% (90% fiducial interval, 3.61% to 8.71%). Sevoflurane MAC in thick-billed parrots determined by mechanical stimulation was similar to values determined in chickens and mammals. Sevoflurane MAC determined by electrical stimulation was significantly higher, which suggested that the 2 types of stimulation did not induce similar results in thick-billed parrots.

Assessment of pain and hemodynamic response in older children undergoing circumcision: Comparison of eutectic lidocaine/prilocaine cream and dorsal penile nerve block

ObjectiveTo evaluate whether dorsal penile nerve block (DPNB) or local topical anesthesia (LT) provided better postoperative analgesia and less hemodynamic stimulation during and after circumcision surgery with Plastibell in older children. MethodsForty-one subjects (age: 2–13 years) undergoing circumcision with Plastibell were randomly divided into LT and DPNB groups. Inhalation induction was performed with an 8% end-tidal sevoflurane concentration. In the LT group, a eutectic ointment of 5% lidocaine and 5% prilocaine was applied to the foreskin 1 h before surgery. At 10 min after anesthesia induction, the end-tidal sevoflurane concentration was decreased to 2%. In the other group, a DPNB was performed with 0.5% bupivacaine (1 mg/kg). Heart rate (HR), respiratory rate, mean arterial pressure (MAP), and involuntary movements were evaluated at anesthesia induction (T0), 1 min after DPNB (T1), 1 min after incision (T2), and 1 min after surgery (T3). Pain was evaluated at 1 and 24 h after surgery, and complications were evaluated at 24 h after surgery. ResultsThe groups were homogeneous with respect to age, weight, glans diameter, penile length, Kayaba classification, and surgical duration. The LT group showed increased HR (p = 0.073) and MAP (p = 0.046) at T2 as compared to T0. No hemodynamic changes were observed in the HPDB group. The LT group showed a higher pain score at 1 h after surgery than the DPNB group, whereas the DPNB group had a higher incidence of hematoma (p = 0.02) at 24 h after surgery. ConclusionAnesthesia with 5% lidocaine and 5% prilocaine cream during circumcision of older children with Plastibell under general anesthesia with sevoflurane does not provide satisfactory perioperative hemodynamic stability or postoperative analgesia.

Non‐steroidal anti‐inflammatory drugs reduce the stress response during sevoflurane anesthesia

Non-steroidal anti-inflammatory drugs are analgesics commonly used for post-operative pain. However, their effect on dosages of inhaled anesthetics during surgery is unclear. We investigated the effect of flurbiprofen axetil and parecoxib sodium on the minimum alveolar concentration of sevoflurane required to blunt stress responses to skin incision under general anesthesia. One hundred and five adult patients were randomly allocated to four treatment groups, each receiving sevoflurane: control (sevoflurane only), lidocaine (1 mg/kg bolus, followed by continuous infusion of 20 μg/kg/min after intubation), Intravenous (IV) flurbiprofen (1 mg/kg before skin incision), and IV parecoxib (40 mg before skin incision). Following anesthetic induction and stabilization of end-tidal sevoflurane concentration, mean arterial blood pressure and heart rate were recorded 2 min before and at 5-min intervals after skin incision. The stable end-tidal sevoflurane concentration was calculated using an up-and-down method. The minimum alveolar concentration of sevoflurane required to blunt the stress responses to skin incision in the control, lidocaine, flurbiprofen, and parecoxib groups was 4.63 ± 0.08%, 2.67 ± 0.08%, 3.33 ± 0.08%, and 3.80 ± 0.11%, respectively. These figures for the later three groups were all significantly less than that of the control group (P = 0.021, P = 0.037, and P = 0.011, respectively); that of the flurbiprofen group was significantly less than the parecoxib (P = 0.034). The non-steroidal anti-inflammatory drugs flurbiprofen axetil and parecoxib sodium decreased the minimum alveolar concentration of sevoflurane required to blunt the stress response to skin incision during general anesthesia.

Comparison of intravenous infusion of dexmedetomidine and midazolam for premedication in children

Objective To compare the efficacy of intravenous infusion of dexmedetomidine and midazolam for premedication in children.Methods Ninety-two ASA Ⅰ or Ⅱ children (46 cases aged 1-3 yr and 46 cases aged 4-6 yr) scheduled for elective general or urologic surgeries,were enrolled in this study.The children were randomly divided into 2 groups (n =46 each):midazolam group (group M) and dexmedetomidine group (group D).The children accompanied by their parents were admitted to the anesthesia preparation room at about 20 min before induction of anesthesia,and midazolam 0.1 mg/kg or dexmedetomidine 1 μg/kg was infused intravenously over 10 min.Anesthesia was induced with proporol-rocuroniume-remifentanil,and maintained with sevoflurane-remifentanil-rocuroniume.Modified Yale Preoperative Anxiety Scale (mYPAS) score,sedation score,HR,mean arterial pressure (MAP),respiratory rate (RR) and SpO2 were recorded before premedication (T1),before separation from their parents (T2) and when entering the operating room (T3).The incidence of sleep (a sedation score of 4) was recorded at T2,3.The end-tidal concentration of sevoflurane,infusion rate of remifentanil,laryngeal air way removal time,emergence time,duration of stay at the recovery room,incidence of delirium during recovery period,the percentage of patients requiring rescue analgesic,and adverse effects were also retorded.Results Compared to that at T1,the mYPAS score was significantly decreased at T2,3,and the sedation score was significantly increased at T2,3 in both groups ( P ＜ 0.05),HR at T2 and MAP at T2,3 were significantly decreased in group D,and HR at T3 was significantly increased in group M ( P ＜ 0.05 ).Compared to group M,the sedation scores and the incidence of sleep were significantly increased at T2,3,and the HR was significantly decreased at T2 in group D ( P ＜ 0.05).There was no significant difference in the mYPAS score,RR,MAP,SpO2,end-tidal concentration of sevoflurane,infusion rate of remifentanil,laryngeal air way removal time,emergence time,duration of stay at the recovery room,incidence of delirium during recovery period,the percentage of patients requiting rescue analgesic,and incidence of adverse effects between D and M groups ( P ＞ 0.05).Conclusion The sedative efficacy of iv dexmedetomidine is superior to that of iv midazolam when infused for premedication in children,but it exerts much influence on hemodynamics,and the changes in hemodynamics should be noted. Key words: Dexmedetomidine; Midazolam; Child; Premedication

Effect of rocuronium 0.3 mg/kg(ED95)for anesthesia induction on monitoring of recurrent laryngeal nerve in patlents undergoing thyroid surgery

Objective To investigate the effect of rocuronium 0.3 mg/kg(ED95)for anesthesia induclion on monitoring of recurrent laryngeal nerve in patients undergoing thyroid surgery.Methods Seventy-five patients,ASA Ⅰ or Ⅱ,aged 20-70 yr,weighing 50-85 kg,scheduled for thyroid surgery,were randomly divided into two groups:rocuronium group(groupⅠ,n=38)and sevoflurane group(group Ⅱ,n =37).Anesthesia was induced with midazolam 2 mg,propofol 2 mg/kg,sulfentanil 0.5 ug/kg.After loss of eyelash reflex,group Ⅰ received rocuronium 0.3 mg/kg(ED95)and was intubated with the electromyographic(EMG)endotracheal tube under glidescope al 2 min after rocuronium administration.Group Ⅱ received sevoflurane inhalation and was endotracheal intubated with EMG tube until end-tidal sevoflurane concentration achieved 4％.Anesthesia was maintained with inhalation of sevoflurane in both groups.SP,DP,and HR were monitored continuously through the surgery.Cooper's score and the success of attempt at endotracheal intubation were recorded.Recurrent laryngeal nerve evoked EMG was recorded by neuromonitoring and the amplitude of EMG responses was recorded at 5 min intervals from 30 min to 70 min of surgery duration.Results SP,DP and HR remained within normal range in both groups.The success rates of endotracheal intubation were 100％ in both groups,but the Cooper' s score of group Ⅰ was significantly higher than that of group Ⅱ(P ＜ 0.05).Compared with group Ⅱ,the amplitude of EMG respouses was significantly decreased in group Ⅰ(P ＜ 0.05).However,the EMG response in group Ⅰ was adequate for neuromonitoring of recurrent laryngeal nerve.Conclusion Rocuronium 0.3 mg/kg(ED95)for anesthesia induction can not only provide satisfied endotracheal intubation conditions,but also be adequate for monitoring of recurrent laryngeal nerve in patients undergoing thyroid surgery. Key words: Androstenols; Anesthesia,general; Intraoperalive complications

The effects of age, isoflurane and sevoflurane on atracurium in lambs

ObjectiveTo determine the effects of age, sevoflurane and isoflurane on atracurium-induced neuromuscular blockade in 3–16 week-old lambs. Study designProspective randomized experimental trial. AnimalsTwenty-six Scottish blackface ewe-lambs were anaesthetized for spinal surgery when either 3–6 (mean age 4.6 weeks; n = 18) or 12–16 weeks (mean age 13.7 weeks; n = 15) of age; seven animals were anaesthetized at both ages. MethodsAfter intramuscular injection of medetomidine (10 μg kg−1) anaesthesia was induced in the younger lambs either with isoflurane or sevoflurane in oxygen delivered by mask, and in the older lambs with ketamine (4 mg kg−1), and midazolam (0.2 mg kg−1) administered intravenously (IV). In both groups anaesthesia was maintained with fixed end-tidal concentrations of either sevoflurane (2.8%) or isoflurane (1.8%) delivered in oxygen. Before surgery meloxicam (0.6 mg kg−1), morphine (0.5 mg kg−1) and ketamine (1 mg kg−1 followed by 10 μg kg−1 minute−1) were administered IV. The lungs were ventilated mechanically to maintain normocapnia. Neuromuscular block was achieved with a loading dose (LD) of atracurium (0.5 mg kg−1 IV). The peroneal nerve was stimulated (train-of-four every 12 seconds). Evoked responses in the digital extensor muscles were evaluated by palpation and observation. Maintenance doses (MD) of atracurium (0.17 mg kg−1 IV) were administered when the first twitch (T1) returned. The onset and duration of LD action (T1 absent) and the duration of MD were recorded. Data were analysed using Student's t test, Mann–Whitney U test, repeated–measures anova, Wilcoxon's matched pairs test or Pearson correlation coefficient as relevant (p < 0.05). ResultsOnset of LD action developed significantly (p < 0.05) more rapidly in isoflurane compared with sevoflurane-anaesthetized lambs (55 ± 18 cf. 80 ± 37 seconds). Duration of action of LDs and MDs was longer (p < 0.05) in lambs aged 12–16 than 3–6 weeks (33 ± 5.4 cf. 25 ± 6.4 and 26 ± 4.2 cf. 18 ± 5.5 minutes) but were independent of the anaesthetic used. Conclusions and clinical relevanceThe effect of atracurium is age-dependent in lambs being prolonged in older animals. The onset of neuromuscular blockade is more rapid in isoflurane compared with sevoflurane-anaesthetized lambs.

Comparison of BIS values in patients under anesthesia with minimum alveolar concentration of sevoflurane and median effective concentration of propofol at loss of consciousness

Objective To compare the BIS values in patients under anesthesia with minimum alveolar concentration (MAC) of sevoflurane and median effective concentration (EC50) of propofol at loss of consciousness.Methods Sixty ASA Ⅰ or Ⅱ patients,aged 18-60 yr,undergoing elective surgery under general anesthesia,were equally and randomly divided into 2 groups:inhalational anesthesia with sevoflurane group (group Sev) and intravenous anesthesia with propofol ( group Pro).The end-tidal concentration of sevoflurane was monitored using Aestiva anesthesia machine (Datex Ohmeda) in group Sev.Anesthesia was induced with intravenous injection of etomidate 0.3 mg/kg,rocuronium 1 mg/kg,and remifentanil 0.2 μg/kg.The patients were mechanically ventilated after tracheal intubafion.Sevoflurane inhalation was started 12.5 min after intubation in group Sev.Propofol was given by target-controlled infusion with the target plasma concentration set at 3.8 μg/ml 12.5 min after intubation in group Pro.When the effect-site concentrations of propofol reached EC50 of propofol at loss of consciousness (2.2 μg/ml),1.3 EC50(2.86 μg/ml) and 1.5 EC50 (3.3μg/ml) and when the end-tidal concentrations of sevoflurane reached 1.0,1.3 and 1.5 MAC,BIS value,MAP and HR were recorded.Results HR was significantly higher at 1.3 MAC or 1.3 EC50,and at 1.5 MAC or 1.5 EC50 in group Pro than in group Sev ( P ＜0.05).BIS value was significantly decreased at 1.3 MAC or 1.3 EC50,and at 1.5 MAC or 1.5 EC50 compared with that at 1.0 MAC or EC50(P ＜0.05).There was no significant difference in MAP and BIS value at each time point between the two groups ( P ＞ 0.05).Conclusion No significant change in BIS values is found in patients under anesthesia with 1.0,1.3 and 1.5 MAC of sevoflurane and with 1.0,1.3 and 1.5 EC50 of propofol. Key words: Anesthetics, inhalation; Propofol; Electroencephalography; Unconsciousness; Doseresponse relationship, drug

The effect of adjuvant drugs on the quality of tracheal intubation without muscle relaxants in children: a systematic review of randomized trials

Intubation without prior administration of muscle relaxants is a common practice in children. However, succinylcholine may be considered as the golden standard for optimizing intubating conditions. We conducted a systematic review of the literature to identify drug combinations that included induction of anesthesia with sevoflurane or propofol. Our aim was to select drug combinations that yield excellent intubating conditions ≥80%; we identified six combinations in children aged 1-9 years. Sevoflurane with remifentanil (1 or 2 μg·kg(-1) ), lidocaine (2 mg·kg(-1) ), or propofol (2 mg·kg(-1) ) as the adjuvant shared the following characteristics: premedication with midazolam and/or ketamine, long sevoflurane exposure time, high inspired and endtidal sevoflurane concentration, and assisted ventilation. One combination using sevoflurane with propofol (3 mg·kg(-1) ) without premedication, with shorter sevoflurane exposure time, and spontaneous breathing indicated that propofol may be the adjuvant of choice for a rapid sevoflurane induction. The only adjuvant identified in propofol induction was remifentanil (4 μg·kg(-1) ). No serious adverse events were reported with these combinations.

Effects of sevoflurane postconditioning on myocardial neutrophil infiltration in patients undergoing cardiac valve replacement under cardiopulmonary bypass

Objective To investigate the effects of sevoflurane postconditioning on myocardial neutrophil infiltration in patients undergoing cardiac valve replacement under cardiopulmonary bypass (CPB).Methods Twenty-four ASA Ⅱ or Ⅲ patients (NYHA Ⅱ or Ⅲ ) of both sexes aged 20-50 yr with BMI of 19-25 kg/m2 undergoing cardiac valve replacement under CPB were randomly divided into 2 groups ( n =12 each):group control (group C) and group sevoflurane postconditioning (group S).Anesthesia was induced with midazolam,fentanyl,etomidate and rocuronium and maintained with iv infusion of fentanyl,midazolam and vecuronium.The patients were intubated and mechanically ventilated (VT 8-10 ml/kg,RR 10-14 bpm,I∶E 1∶2,FiO2 100％ ).PETCO2 was maintained at 35-40 mm Hg.In group S sevoflurane was inhaled immediately after aorta and vena cava were unclamped.The end-tidal sevoflurane concentration was maintained at 1.7％ for 5 min.Arterial blood samples were collected before surgery and at 1,2 and 4 h after aortic unclamping for determination of plasma cardiac troponin T concentration.Myocardial specimens were obtained from right auricular appendage after opening of pericardium and at 1 h after aortic unclamping for microscopic examination and determination of myocardial myeloperoxidase expression.Results Sevoflurane postconditioning significantly decreased plasma cardiac troponin T concentration and myocardial myeloperoxidase expression and ameliorated histo-pathological damage in group S as compared with group C.Conclusion Myocardial neutrophil infiltration is involved in the protective effect of sevoflurane postconditioning against myocardial injury in patients undergoing cardiac valve replacement under CPB. Key words: Anesthetics, inhalation; Neutrophils; Cardiopulmonary bypass; Heart valve prosthesis implantation

Effects of minimal-flow sevoflurane anesthesia combined with Amsorb Plus calcium lime on hepatic and renal functions

Objective To investigate the effects of minimal-flow sevoflurane anesthesia combined with a new CO2 adsorbent Amsorb Plus calcium lime on the hepatic and renal functions in patients.Methods Seventytow ASA Ⅰ or Ⅱ patients,aged 20-60 yr,scheduled for gastrointestinal surgery under general anesthesia,were randomized into 2 groups (n =36 each):middle-flow anesthesia group (group G1 ) and minimal-flow anesthesia group (group G2 ).Amsorb Plus calcium lime was added into the CO2 absorption canister and the core temperature of the calcium lime was continuously monitored and recorded.The patients were tracheal intubated after anesthesia induction and mechanically ventilated.The initial sevoflurane concentration was set at 4％ and the fresh gas flow of oxygen was set at 4 L/min.After the end-tidal concentration of sevoflurane reached 2.6％,the fresh gas flow of oxygen was adjusted to 2 L/min in group G1 or 0.5 L/min in group G2.The end-tidal concentration of sevoflurane was maintained at 2.4％-2.8％ during operation.Venous blood samples were taken 24 h before and 24 h after operation for determination of the serum concentrations of total bilirubin (TBIL),direct bilirubin (DBIL),blood urea nitrogen (BUN) and creatinire (Cr) and activities of alanine aminotransferase (ALT) and aspartate aminotransferase (AST).Urine samples were obtained at 24 h before and after operation to detect the concentration of glucose and protein.The urine glucose and protein positive patients were recorded.Results There was no significant difference in the core temperature of calcium lime at different time points between the two groups ( P ＞ 0.05 ).Compared with that at 24 h before operation,AST activity,TBIL and DBIL concentrations were significantly increased,BUN concentration was significantly decreased,but no significant change was found in the Cr concentration and the number of urine glucose and protein positive patients at 24 h after operation in group G1,and DBIL concentration was significantly increased,while BUN concentration was significantly decreased at 24 h after operation in group G2 ( P ＜ 0.05 ).There was no significant difference in the parameters of hepatic and renal functions between the two groups ( P ＞ 0.05).Conclusion The combination of minimal-flow sevoflurane anesthesia and Amsorb Plus calcium lime exerts no effect on the hepatic and renal functions,the effect is similar to that of middle-flow anesthesia,and it can be safely used in patients. Key words: Anesthetics,inhalation; Anesthesia,inhalation; Liver function tests; Kidney function tests

Effects of lidocaine constant rate infusion on sevoflurane requirement, autonomic responses, and postoperative analgesia in dogs undergoing ovariectomy under opioid-based balanced anesthesia

The effects of constant rate infusion (CRI) of lidocaine on sevoflurane (SEVO) requirements, autonomic responses to noxious stimulation, and postoperative pain relief were evaluated in dogs undergoing opioid-based balanced anesthesia. Twenty-four dogs scheduled for elective ovariectomy were randomly assigned to one of four groups: BC, receiving buprenorphine without lidocaine; FC, receiving fentanyl without lidocaine; BL, receiving buprenorphine and lidocaine; FL, receiving fentanyl and lidocaine. Dogs were anesthetized with intravenous (IV) diazepam and ketamine and anesthesia maintained with SEVO in oxygen/air. Lidocaine (2mg/kg plus 50 μg/kg/min) or saline were infused in groups BL/FL and BC/FC, respectively. After initiation of lidocaine or saline CRI IV buprenorphine (0.02 mg/kg) or fentanyl (4 μg/kg plus 8 μg/kg/h CRI) were administered IV in BC/BL and FC/FL, respectively. Respiratory and hemodynamic variables, drug plasma concentrations, and end-tidal SEVO concentrations (E'SEVO) were measured. Behaviors and pain scores were subjectively assessed 1 and 2h post-extubation. Lidocaine CRI produced median drug plasma concentrations <0.4 μg/mL during peak surgical stimulation. Lidocaine produced a 14% decrease in E'SEVO in the BL (P<0.01) but none in the FL group and no change in cardio-pulmonary responses to surgery or postoperative behaviors and pain scores in any group. Thus, depending on the opioid used, supplementing opioid-based balanced anesthesia with lidocaine (50 μg/kg/min) may not have any or only a minor impact on anesthetic outcome in terms of total anesthetic dose, autonomic responses to visceral nociception, and postoperative analgesia.

Remifentanil Prevents Tourniquet-Induced Arterial Pressure Increase in Elderly Orthopedic Patients under Sevoflurane/N2O General Anesthesia

Aims: Prolonged tourniquet inflation produces a hyperdynamic cardiovascular response. We investigated the effect of continuous remifentanil infusion on systemic arterial pressure, heart rate, and cardiac output changes during prolonged tourniquet use in elderly patients under sevoflurane/N2O general anesthesia.Methods: Thirty female patients scheduled for knee replacement arthroplasty were infused with either remifentanil at a target organ concentration of 2.0 ng/mL (remifentanil group, n = 15) or saline (control group, n = 15) after induction of anesthesia. Anesthesia was maintained with sevoflurane and N2O. Heart rate (HR), systolic arterial pressure (SAP), diastolic arterial pressure (DAP), cardiac index (CI), total systemic vascular resistance index (TSVRI), BIS, end-tidal sevoflurane concentration (EtSEVO), and end-tidal carbon dioxide concentration (EtCO2) were measured during the study period.Results: There were significant differences in mean HR, SAP, DAP, and EtSEVO over time between the groups (P = 0.047, P < 0.001, P = 0.017, and P < 0.001, respectively). There was a statistically significant time trend effect (P < 0.001) in HR, SAP, DAP, and CI between the groups, with a statistically significant time-group interaction between the two groups (P = 0.02, 0.007, 0.001, 0.01, respectively).Conclusion: The present study demonstrated that infusion with remifentanil prevented an increase in hemodynamic pressure during tourniquet inflation in elderly patients under sevoflurane/N2O general anesthesia.

Effect of intraoperative lidocaine on anesthetic consumption, and bowel function, pain intensity, analgesic consumption and hospital stay after breast surgery

BackgroundPerioperative lidocaine infusion improves postoperative outcomes, mostly after abdominal and urologic surgeries. Knowledge of the effect of lidocaine on peripheral surgeries is limited. Presently, we investigated whether intraoperative lidocaine infusion reduced anesthetic consumption, duration of ileus, pain intensity, analgesic consumption and hospital stay after breast plastic surgeries.MethodsSixty female patients, aged 20-60 years, enrolled in this prospective study were randomly and equally divided to two groups. One group (n = 30) received a 1.5 mg/kg bolus of lidocaine approximately 30 min before incision followed by continuous infusion of lidocaine (1.5 mg/kg/h) until skin closure (lidocaine group). The other group (n = 30) was untreated (control group). Balanced inhalation (sevoflurane) anesthesia and multimodal postoperative analgesia were standardized. End tidal sevoflurane concentration during surgery, time to the first flatus and defecation, visual analog pain scale (0-10), analgesic consumption and associated side effects at 24, 48, and 72 h after surgery, hospital stay, and patient's general satisfaction were assessed.ResultsCompared to the control group, intraoperative lidocaine infusion reduced by 5% the amount of sevoflurane required at similar bispectral index (P = 0.014). However, there were no significant effects of lidocaine regarding the return of bowel function, postoperative pain intensity, analgesic sparing and side effects at all time points, hospital stay, and level of patient's satisfaction for pain control.ConclusionsLow dose intraoperative lidocaine infusion offered no beneficial effects on return of bowel function, opioid sparing, pain intensity and hospital stay after various breast plastic surgeries.

Remifentanil ve Fentanil Temelli Sevofluran Anestezisinin Hemodinami Derlenme Profili ve Maliyetlerinin Karşılaştırılması

Objective: This trial was designed to compare the effects of fentanyl and remifentanil on hemodynamic parameters, postoperative recovery, sevoflurane consumption and the cost of anesthetics. Material and Methods: Cases that were scheduled to undergo elective laparoscopic cholecystectomy surgery were assigned to two groups with simple random sampling method, as Group F (Fentanyl) and Group R (Remifentanil), each including 30 patients. The anesthetic induction was initiated by administering 1-2 mg/kg propofol bolus based on the bispectral index (BIS) value followed by 2 µg/kg fentanyl in Group F patients and 1 µg/kg remifentanil in Group R patients administered in 60 seconds as iv bolus; subsequently, 0.5 mg/kg iv atracurium was administered. For maintenance of anesthesia, 50% oxygen in-air was administered at 4 L/min; the end-tidal sevoflurane concentration was adjusted to achieve a BIS value of 45 to 55. In Group R, remifentanil 0.25 µg/kg/min infusion was continued. The addition of 0.5 µg/kg fentanyl was planned as required in Group F. Sevoflurane end-tidal concentration and the changing times were recorded. For each case, the sevoflurane consumption was calculated using the Dion formula. Results: In Group R, the hemodynamic control, particularly the suppression of response to intubation was more successful than in Group F. The eye opening times and Post Anesthesia Care Unit (PACU) transfer times were shorter in Group R relative to Group F (p=0.001 and p=0.001, respectively). Sevoflurane consumption was lower in the Group R (7.18±3.45 mL) compared to Group F (16.45±7.15 mL) (p=0.001). The total anesthetic drug cost was similar between the groups. Conclusion: Compared to fentanyl, remifentanil provided a better intraoperative hemodynamic control, faster postoperative recovery and a favorable effect on anesthetic drug cost by decreasing sevoflurane consumption, eliminating the disadvantages of its price.