The utility of the perfusion index as an indicator of anesthetic depth for repeated propofol sedation in children: An observational study.

BACKGROUND: Children receiving proton therapy require repeated sedation. In this study, we aimed to investigate the utility of the perfusion index (PI) for evaluating consciousness level during repeated propofol sedation. METHODS: In this prospective observational study, children aged from birth to 19 years old scheduled for proton therapy under repeated propofol sedation were enrolled. The primary outcome was the equivalence of PI values 5 min after anesthesia induction on consecutive sedation. Total consumption of propofol during sedation, time to reach the University of Michigan sedation scale (UMSS) score 1 after end of proton therapy, and duration of post-anesthesia care unit (PACU) stay were recorded. RESULTS: The PI values measured 5 min after induction of anesthesia were not equivalent to each other in consecutive sedation except for the second versus third (1st vs. 2nd: 97.5% CI: -1.34, 0.91; p = 0.206, 0.034; 2nd vs. 3rd: 97.5% CI: -0.87, 0.94; p = 0.023, 0.036 3rd vs. 4th: 97.5% CI: -2.08, -0.26; p < 0.99, <0.001; 4th vs. 5th: 97.5% CI: 0.21, 2.28; p < 0.001, >0.99; respectively). In consecutive sedation, there was not a significantly different difference in the time to reach UMSS score 1 (p > 0.99, all) for total consumption of propofol, time to reach UMSS score 1 after the end of proton therapy, and duration of PACU stay. CONCLUSIONS: During repeated propofol sedation in children, PI was insufficient to be used as an indicator of consciousness level assessment. However, we suggest that the information related to repeated sedation provided by this study may be helpful in clinical practice.

Correlation between bispectral index and patient state index in children under sevoflurane anesthesia.

BACKGROUND: Because the unanticipated arousal or hemodynamic instability during anesthesia may adversely affect the physical and emotional welfare of children, adequate management of the anesthesia depth is required. We aimed to compare Bispectral Index (BIS) and Patient State Index (PSI) in children during sevoflurane anesthesia and evaluate PSI as depth of anesthesia monitor in children aged 6 months-12 years. METHODS: In this prospective observational study, children aged 6 months-12 years old scheduled for elective surgery under sevoflurane anesthesia were enrolled from November 2018 to June 2019. We monitored BIS and PSI at different sevoflurane concentrations. The primary outcome was the correlation between BIS and PSI. The correlation between BIS and PSI at different sevoflurane concentrations (at 1, 1.5, and 2 MACs) and at different age groups (6 months-2 years, 2-7 years, and 8-12 years) was also investigated. RESULTS: Bispectral index and PSI showed a fair correlation (r = .430; 95% confidence interval [CI], 0.297-0.546; p < .001). Two values were fairly correlated at 1, 1.5, and 2 MAC (r = .544; 95% CI, 0.314-0.716; p < .001, r = .509; 95% CI, 0.283-0.699; p < .001, and r = .315; 95% CI, 0.047-0.522; p = 0.007). BIS and PSI values showed a fair correlation in 6 months - 2 year and 8-12 year groups (r = .696; 95% CI, 0.519-0.813; p < .001 and r = .297; 95% CI, -0.017 to 0.543; p < .021), but there was not significant correlation in 2-7 years group (r = .190; 95% CI, -0.015 to 0.374; p = .052). CONCLUSIONS: There was a fair correlation between BIS and PSI in children under sevoflurane anesthesia. The use of BIS and PSI as an indicator for anesthesia depth by sevoflurane is not reliable in pediatric patients.

Incidence and risk factors of unplanned intubation during pediatric sedation for MRI.

BACKGROUND: It is often difficult for the pediatric patient to cooperate or to remain immobile during MR scans. Therefore, sedation is usually needed for children. PURPOSE: To evaluate the incidence and contributing factors of unanticipated intubation during sedation for MRI scan in children. STUDY TYPE: Retrospective observational study. POPULATION/SUBJECTS: In all, 1165 charts were reviewed retrospectively of patients who had been sedated by anesthesiologists at a single institution from May 2015 to June 2016. ASSESSMENT: Patient's demographics, the region of the MRI scan, total amount of medication, duration of sedation, and any adverse event during MRI were assessed. The adverse events during sedation including airway obstruction, apnea, desaturation, bradycardia, and hypotension were also assessed. STATISTICAL TESTS: Risk factors of unplanned intubation during MRI sedation were identified by univariate and multivariate analysis. Firth's exact logistic regression was used for univariate and multivariate analysis. According to the results from multiple logistic regression, a nomogram was developed to predict the risk. RESULTS: A total of 1165 children aged 7 days to 18 years with sedation used during an MRI scan during the study period showed an incidence of unexpected intubation as ~2% (n = 23, 95% confidence interval [CI]; 0.0123, 0.0295). Multivariate logistic regression revealed the following risk factors of unplanned intubation: American Society of Anesthesiologists (ASA) class III patients (odds ratio [OR] 1.212, P < 0.001), premature birth (OR 2.317, P < 0.001), and the presence of gastroesophageal reflux disease (GERD) (OR 1.474, P < 0.001) or congenital heart disease (OR 1.118, P < 0.001). DATA CONCLUSION: This study identified risk factors of unplanned intubation as follows: ASA class III patients, premature birth, and the presence of GERD or congenital heart disease. The physician should screen risk factors of unexpected intubation and maintain adequate sedation during MRI scans in pediatric patients. Level of Evidence 3. Technical Efficacy Stage 5. J. Magn. Reson. Imaging 2019;49:1053-1061.

Ultrasound-guided vs. palpation-guided techniques for radial arterial catheterisation in infants: A randomised controlled trial.

BACKGROUND: The usefulness of ultrasound-guided techniques for radial arterial catheterisation has been well identified; however, its usefulness has not been completely evaluated in infants under 12 months of age, who are generally considered the most difficult group for arterial catheterisation. OBJECTIVE: We evaluated whether ultrasound guidance would improve success rates and reduce the number of attempts at radial arterial catheterisation in infants. DESIGN: A randomised, controlled and patient-blinded study. SETTING: Single-centre trial, study period from June 2016 to February 2017. PATIENTS: Seventy-four infants undergoing elective cardiac surgery. INTERVENTION: Patients were allocated randomly into either ultrasound-guided group (group US) or palpation-guided group (group P) (each n=37) according to the technique applied for radial arterial catheterisation. All arterial catheterisations were performed by one of two experienced anaesthesiologists based on group assignment and were recorded on video. MAIN OUTCOME MEASURES: The primary endpoint was the first-pass success. The number of attempts and total duration of the procedure until successful catheterisation were also analysed. RESULTS: The first-pass success rate was significantly higher in the group US than in the group P (68 vs. 38%, P = 0.019). In addition, fewer attempts were needed for successful catheterisation in the group US than in the group P (median 1 [IQR 1 to 2] vs. 2 [1 to 4], P = 0.023). However, the median [IQR] procedural time (s) until successful catheterisation in the two groups was not significantly different (102 [49 to 394] vs. 218 [73 to 600], P = 0.054). CONCLUSION: The current study demonstrated that the ultrasound-guided technique for radial arterial catheterisation in infants effectively improved first-pass success rate and also reduced the number of attempts required. TRIAL REGISTRATION: ClinicalTrials.gov NCT02795468.

Incidence of tolerance in children undergoing repeated administration of propofol for proton radiation therapy: a retrospective study.

BACKGROUND: Propofol is an excellent hypnotic drug for use in repeated radiation procedures in young children. To date, tolerance to propofol generally does not develop in pediatric patients undergoing radiation therapy. However, several studies have suggested that there may be potential for development of tolerance to propofol. The aim of this study was to evaluate the development of a tolerance to propofol used for repeated deep sedation in children undergoing proton radiation therapy (PRT). METHODS: All children undergoing PRT at our institution between December 2015 and January 2018 were eligible for inclusion in this study. Sedation was induced by a bolus dose of propofol (2.0 mg.kg- 1) followed by a continuous infusion of 250 µg.kg- 1.min- 1 via an infusion pump to achieve deep sedation. Sedation was maintained with the propofol infusion of 200 µg.kg- 1.min- 1, which was adjusted in 25 µg.kg- 1.min- 1 increments up or down as necessary to ensure deep sedation. The primary outcome was mean doses of propofol over time. RESULTS: Fifty-eight children were analyzed. The mean (SD) age was 4.5 (2.1) years. The mean (SD) number of treatment sessions was 19 (7). Fifteen patients (26%) developed tolerance to propofol. However, there were no significant differences between the children who developed tolerance and the children who did not develop tolerance in mean propofol dose and awakening time over time (p = 0.887 and P = 0.652, respectively). Age, the number of PRT, and attending anesthesiologists was not significantly associated with the incidence of tolerance to propofol. CONCLUSION: Repeated prolonged deep sedation for PRT elicited multiple times over several weeks in young children using propofol did not develop tolerance in 74% of patients. Although the incidence of 26% tolerance to propofol may still be present, the increase in propofol dose was minimal. Therefore, the use of repeated propofol for children was safe.

A retrospective comparison of propofol to dexmedetomidine for pediatric magnetic resonance imaging sedation in patients with mucopolysaccharidosis type II.

BACKGROUND: Mucopolysaccharidosis type II patients are reported to have an elevated incidence of difficult airway. Propofol is a commonly used sedative for magnetic resonance imaging in pediatric patients, but patients who receive it may exhibit dose-dependent upper airway obstruction and respiratory depression. Dexmedetomidine also provides adequate procedural sedation with a relatively low risk of airway obstruction. Accordingly, we introduced the use of dexmedetomidine in our practice to reduce the risk of airway obstruction during magnetic resonance imaging procedures. AIMS: The aim of this study was to evaluate the incidence of artificial airway interventions in patients sedated with propofol and compare it to that in patients sedated with dexmedetomidine in patients with mucopolysaccharidosis type II during magnetic resonance imaging procedures. METHODS: All mucopolysaccharidosis type II patients undergoing magnetic resonance imaging at our institution between April 2014 and February 2018 were included in this study. The patients were divided into two groups according to whether they were managed before and after the introduction of dexmedetomidine: those who were sedated with propofol (group P) and those who were sedated with dexmedetomidine (group D). RESULTS: Forty-six sedations were performed in 27 patients. Artificial airway interventions were significantly more frequent during propofol-based than dexmedetomidine-based sedation: 14 of 32 (43.8%) in group P and 1 of 14 (7.1%) in group D (odds ratio, 10.11; 95% confidence interval, 1.18-86.85; P = 0.018). Time to awake and time to discharge were similar between groups. Changes in hemodynamic variables also did not significantly differ between groups. CONCLUSION: Dexmedetomidine provides an adequate level of sedation and is associated with lower rates of artificial airway interventions compared to propofol. Therefore, dexmedetomidine may offer advantages for preserving the native airway compared to propofol when administered during magnetic resonance imaging scans in patients with mucopolysaccharidosis type II.

A comparison of the use of propofol alone and propofol with midazolam for pediatric magnetic resonance imaging sedation - a retrospective cohort study.

BACKGROUND: Pediatric MRI sedation performed by a variety of specialists such as sedationists and anesthesiologists commonly uses propofol, which has similar effects to an ideal sedative agent for maintaining deep sedation. However, when propofol is used, adverse airway events are relatively more common than when using other sedative agents. The concomitant administration of midazolam and propofol can reduce the dose of propofol needed for adequate sedation and might also reduce the frequency of airway obstruction without affecting the patient's recovery profile. METHODS: We reviewed the our hospital records of all pediatric MRI sedation patients aged 3 to 16 years who were sedated with either propofol alone or propofol with midazolam between December 2013 and June 2016. RESULTS: Eight hundred ninety-seven pediatric MRI sedation patients were included (n = 897). The frequency of airway intervention was 25/356 (7.0%) in Group P and 15/541 (2.8%) in Group PM (difference in proportions: 4.2%; 95% CI: 1.4-7.6%; p = 0.002). The mean (SD) time to awake was longer in Group PM compared to Group P [21.2 (5.6) minutes vs. 23.0 (7.1) minutes; mean difference, 1.8 min; 95% CI, 0.9-2.9; p < 0.001]. The mean (SD) time to discharge was longer in Group PM compared to Group P [34.5 (6.9) minutes vs. 38.6 (9.4) minutes; mean difference, 4.0 min; 95% CI, 3.0-5.1; p < 0.001]. CONCLUSIONS: The administration of a small dose of midazolam during pediatric MRI sedation using propofol can reduce the frequency of airway complications without prolonging the clinically significant recovery profile.

Pulse-pressure variation predicts fluid responsiveness during heart displacement for off-pump coronary artery bypass surgery.

OBJECTIVE: The aim of this study was to evaluate the ability of pulse-pressure variation to predict fluid responsiveness during heart displacement for off-pump coronary artery bypass surgery using receiver operating characteristic analysis. DESIGN: A prospective study. SETTING: A clinical study in a single cardiac anesthesia institution. PARTICIPANTS: Thirty-five patients undergoing elective off-pump coronary artery bypass surgery. MEASUREMENTS AND MAIN RESULTS: Central venous pressure, pulmonary arterial occlusion pressure, pulse-pressure variation, and cardiac index were measured 5 minutes after revascularization of the left anterior descending coronary artery and before heart displacement. Immediately after heart displacement for revascularization of the left circumflex artery, and 10 minutes after fluid loading with hydroxyethyl starch 6% (10 mL/kg) during heart displacement, the measurements were repeated. Patients whose cardiac indices increased by ≥15% from fluid loading were defined as responders. After heart displacement, only pulse-pressure variation showed significant difference between the responders and nonresponders (13.48 ± 6.42 v 7.33 ± 3.81, respectively; p < 0.01). Moreover, receiver operating characteristic analysis showed that pulse-pressure variation successfully predicted fluid responsiveness (area under the curve = 0.839, p = 0.0001). Pulse-pressure variation >7.69% identified the responders, with a sensitivity of 86% and a specificity of 83%. CONCLUSIONS: Pulse-pressure variation successfully predicted fluid responsiveness and would be useful in guiding fluid management during heart displacement for off-pump coronary artery bypass surgery.

Pulse pressure variation as a predictor of fluid responsiveness during one-lung ventilation for lung surgery using thoracotomy: randomised controlled study.

BACKGROUND AND OBJECTIVE: Pulse pressure variation (PPV) is increasingly advocated as a predictor of fluid responsiveness in patients receiving mechanical ventilation. However, the ability of PPV has never been studied during one-lung ventilation (OLV). Therefore, we evaluated the value of PPV to predict fluid responsiveness in patients receiving conventional and protective OLV using receiver operating characteristic (ROC) analysis, respectively. METHODS: Forty-nine patients undergoing lung surgery requiring OLV were enrolled in this study. Patients were randomised either to group P [patients receiving protective OLV with tidal volume 6 ml kg, inspired oxygen fraction (FIO2) of 0.5 and positive end-expiratory pressure (PEEP) of 5 cmH2O) or group C (patients receiving conventional OLV with tidal volume of 10 ml kg, FIO2 of 1.0 and no PEEP). Following OLV, PPV and cardiac output were measured before and 12 min after fluid loading (7 ml kg hydroxyethyl starch 6%). Patients whose cardiac indices increased by at least 15% to fluid loading were defined as the responders. RESULTS: The areas under ROC curve for PPV were 0.857 (P = 0.006) in group P and 0.524 (P = 0.839) in group C, respectively. The optimal threshold value given by ROC analysis for PPV was 5.8% in group P. CONCLUSIONS: PPV could predict fluid responsiveness only during protective OLV, but not conventional OLV. PPV would be helpful for fluid management in patients receiving protective OLV for lung surgery using thoracotomy.

Comparison of Jaw Elevation Device vs. Conventional Airway Assist during Sedation in Chronic Kidney Diseases Undergoing Arteriovenous Fistula Surgery: A Randomized Controlled Trial.

Patients with chronic renal failure (CRF) are likely to have obstructive sleep apnea (OSA) underdiagnosed, and maintaining airway patency is important during sedation. This study compared Jaw elevation device (JED) with conventional airway interventions (head lateral rotation, neck extension, oral or nasal airway insertion, and jaw thrust maneuver) during sedation and hypothesized that JED may be effective to open the airway. A total of 73 patients were allocated to a conventional group (n = 39) and a JED group (n = 34). The number of additional airway interventions was the primary outcome. Percentage of patients with no need of additional interventions and apnea-hypopnea index (AHI) were secondary outcomes. The number of additional interventions was significantly less in the JED group compared to the conventional group (0 (0-0) vs. 1 (0-2); p = 0.002). The percentage of patients with no requirement for additional interventions was significantly higher in the JED group compared to the conventional group (76.5% vs. 43.6%; p = 0.004). AHI was significantly lower in the JED group compared to the conventional group (4.5 (1.5-11.9) vs. 9.3 (3.8-21.9), p = 0.015). In conclusion, JED seems to be effective in opening the airway patency during sedation in CRF patients.

Improvement of laryngoscopic view by hand-assisted elevation and caudad traction of the shoulder during tracheal intubation in pediatric patients.

Pediatric patients have large heads and relatively small bodies, making it difficult to perform intubation even in the sniffing position. Therefore, this study was planned on the assumption that hand-assisted elevation and caudad traction of the shoulder (HA-ECTS) would compensate for the laryngoscopic view. In this observational study, 45 pediatric patients aged 0-36 months with an ASA physical status of I-III and scheduled for elective surgery under general anesthesia were enrolled. HA-ECTS was defined as hand-assisted personalized traction in the upper and caudad directions with both hands under the lower cervical area. The POGO (percentage of glottis opening) score, MO (mouth opening), and LHS (laryngoscopic handling score) were compared before and after HA-ECTS. The median [range] POGO score was 30[10-50]% and 60[15-80]% before and after HA-ECTS, respectively (median difference, 20; 95% confidence interval [CI] 10 to 25%; P = 0.002). MO was 1.0[0.8-1.9] cm and 1.8[1.3-2.0] cm before and after HA-ECTS, respectively (median difference, 0.45 cm; 95% CI 0.25 to 0.60; P < 0.001). The ease of laryngoscopic handling was improved after HA-ECTS(P < 0.001). The application of HA-ECTS to pediatric patients younger than 3 years improved POGO score, MO, and LHS and could prove to be an assistive technique for tracheal intubation.

Effect-site concentration of remifentanil for smooth emergence from sevoflurane anesthesia in patients undergoing endovascular neurointervention.

During emergence from general anesthesia, coughing caused by the endotracheal tube frequently occurs and is associated with various adverse complications. In patients undergoing endovascular neurointervention, achieving smooth emergence from general anesthesia without coughing is emphasized since coughing is associated with intracranial hypertension. Therefore, the up-and-down method was introduced to determine the effective effect-site concentration (Ce) of remifentanil to prevent coughing in 50% and 95% (EC50 and EC95) of patients during emergence from sevoflurane anesthesia for endovascular neurointervention. A total of 43 participants, American Society of Anesthesiologists class I or II participants, aged from 20 to 70 years who were undergoing endovascular neurointervention through transfemoral catheter for cerebrovascular disease were enrolled. Using the up-and-down method with isotonic regression, the EC50 and EC95 of remifentanil to prevent coughing during emergence from sevoflurane anesthesia were determined. We also investigated differences of hemodynamic and recovery profiles between the cough suppression group and the cough group. In total, 38 of 43 patients were included for estimation of EC50 and EC95. The EC50 and EC95 of remifentanil to prevent coughing were 1.42 ng/mL (95% confidence interval [CI], 1.28-1.56 ng/mL) and 1.70 ng/mL (95% CI, 1.67-2.60 ng/mL), respectively. There was comparable emergence and recovery data between the cough suppression group (n = 22) and the cough group (n = 16). However, the Ce of remifentanil and total dose of remifentanil were significantly higher in the cough suppression group (P = 0.002 and P = 0.004, respectively). Target-controlled infusion of remifentanil at 1.70 ng/mL could effectively prevent extubation-related coughing in 95% of neurointervention patients, which could ensure smooth emergence.

Comparison of thoracic epidural pressure in the sitting and lateral decubitus positions.

BACKGROUND: The hanging drop technique identifies the epidural space using the negative pressure of this space. Although the hanging drop technique is popular at the thoracic level, there is still controversy on the negative epidural pressure at this level. The authors hypothesized that the epidural pressure is more consistently negative in the sitting position than in the lateral decubitus position at the thoracic level. METHODS: This study compared the epidural pressures of 28 awake patients in the sitting (sitting group, n = 14) or lateral decubitus (lateral group, n = 14) position. The T5-T6 epidural pressure was measured using a closed pressure measurement system connected to a Tuohy needle. RESULTS: All of the thoracic epidural pressures in the sitting group were negative (median, -5 mmHg; range, -18 to -1; mean, -7.2; SD, 6.3), in contrast to the lateral group (median, 5 mmHg; range, -4 to 13; mean, 5.1; SD, 4.4). The thoracic epidural pressure in the sitting group was significantly lower than in the lateral group (P < 0.001). CONCLUSIONS: The thoracic epidural pressure is more negative in the sitting position than in the lateral decubitus position. These results suggest that the patient should be sitting when the hanging drop technique is used to identify the epidural space.

Analysis of the functionally-narrowest portion of the pediatric upper airway in sedated children.

The narrowest portions of the pediatric larynx are the glottis and subglottic region. However, the pliable and paralyzed subglottic region, acting like a curtain, is no resistance when passing an endotracheal tube. Therefore, the 'functionally' portion of the pediatric upper airway, which may be the most vulnerable to damage during intubation, is the unyielding portion below the cricoid cartilage. We investigated the functionally-narrowest portion below the cricoid cartilage.Computed tomography (CT) was performed under deep sedation. CT images were used for measurement of dimensions and cross-sectional area (CSA) of the larynx at the level of the cricoid, subcricoid, and trachea. We analyzed the anteriorposterior (AP) diameter, transverse diameter, and CSA below the cricoid cartilage (at the cricoid, subcricoid, and tracheal levels).CT images of 46 children from 8 months to 96 months were reviewed from electric medical record (EMR). The mean ±â€ŠSD of AP diameter was the shortest at the subcricoid level (cricoid, 105.7 ±â€Š15.8 mm; subcricoid, 94.6 ±â€Š15.3 mm; and trachea, 101.5 ±â€Š15.7 mm; P < .001). The mean ±â€ŠSD of transverse diameter was the shortest at the trachea level (cricoid, 99.8 ±â€Š12.2 mm; subcricoid, 102.5 ±â€Š13.7 mm; and trachea, 98.8 ±â€Š10.7 mm; P = .01). The mean ±â€ŠSD of CSA was the smallest at the subcricoid level (cricoid, 8781.5 ±â€Š1963.3 mm; subcricoid, 8425.0 ±â€Š2025.7 mm; and trachea, 8523.7 ±â€Š1791.1 mm; P = .02). The AP diameter at the subcricoid level was narrower than the transverse diameter at trachea level (mean difference: 4.2 mm, 95% confidence interval [CI]: 0.7-7.7, P = .02).Since the most susceptible portion for airway damage is unyielding portion, our findings suggest that, functionally, the narrowest portion of the pediatric larynx is located in the subcricoid region.

Anesthetic management for percutaneous computed tomography-guided radiofrequency ablation of reninoma: a case report.

A reninoma is an uncommon, benign, renin-secreting juxtaglomerular cell tumor that causes secondary hypertension in young patients. This hypertension is treated by tumor resection. Except for increased levels of plasma renin and angiotensin I and II, the other physical and laboratory examinations and electrocardiographs were within normal limits upon admission of a 19-year-old woman with a reninoma. For percutaneous computed tomography-guided radiofrequency ablation, general anesthesia was induced by thiopental sodium and rocuronium bromide and maintained with servoflurane (2-4 vol%) and oxygen. The operation ended uneventfully in hemodynamic stability. However, the patient complained of dizziness while sitting 5 hours after the operation, and hypotension was diagnosed. After aggressive normal saline (1 L) infusion over 30 min, the hypotension was corrected and the patient recovered without any other surgical complications. Here, we report the anesthetic management of a patient who underwent percutaneous computed tomography-guided radiofrequency ablation for reninoma destruction, particularly focusing on postoperative hypotension.

Axillary approach versus the infraclavicular approach in ultrasound-guided brachial plexus block: comparison of anesthetic time.

BACKGROUND: With ultrasound guidance, the success rate of brachial plexus block (BPB) is 95-100% and the anesthetic time has become a more important factor than before. Many investigators have compared ultrasound guidance with the nerve stimulation technique, but there are few studies comparing different approaches via the same ultrasound guidance. We compared the axillary BPB with the infraclavicular BPB under ultrasound guidance. METHODS: Twenty-two ASA physical status I-II patients presenting with elective forearm surgery were prospectively randomized to receive an axillary BPB (group AX) or an infraclavicular BPB (group IC) with ultrasound guidance. Both groups received a total of 20 ml of 1.5% lidocaine with 5 µg/ml epinephrine and 0.1 mEq/ml sodium bicarbonate. Patients were then evaluated for block onset and block performance time was also recorded. RESULTS: Group IC demonstrated a reduction in performance time vs. group AX (622 ± 139 sec vs. 789 ± 131 sec, P < 0.05). But, the onset time was longer in group IC than in group AX (7.7 ± 8.8 min vs. 1.4 ± 2.3 min, P < 0.05). All blocks were successful in both groups. CONCLUSIONS: Under ultrasound guidance, infraclavicular BPB was faster to perform than the axillary approach. But the block onset was slower with the infraclavicular approach.

Gender difference and change of α(1)-adrenoceptors in the distal mesenteric arteries of streptozotocin-induced diabetic rats.

BACKGROUND: The purpose of this study was to evaluate the gender-related changes in the function and distribution of α(1)-adrenoceptors in the distal mesenteric artery of streptozotocin (STZ)-induced diabetic rats at the level of α(1)-adrenoceptor subtypes. METHODS: Diabetes was induced by intravenous injection of STZ in a dose of 60 mg/kg through the tail vein in 8 week-old male or female Sprague-Dawley rats (n = 13/group). Age-matched normal rats (n = 15) were used as a control group. Four weeks after STZ injection, the change in mean arterial pressure caused by a 45° tilting was recorded. The α(1)-adrenoceptor subtypes mediating contractions of the distal mesenteric artery were investigated using the agonist, phenylephrine as well as subtype-selective antagonists including prazocin, 5-methylurapidil, and BMY 7378. The expression of α(1)-adrenoceptor subtypes of each artery was examined by immunofluorescence staining and western blotting using subtype selective antibodies. RESULTS: Compared with normal male rats, the contractile response to phenylephrine was decreased in the distal mesenteric artery in normal female rats. Moreover, a decrease in contractile force was observed in STZ-induced diabetic rats compared with age-matched controls. Western blotting revealed that there was the difference between normal male and female rats in manifestation of the α(1D)-adrenoceptor. In STZ-induced male and female diabetic rats, all α(1)-adrenoceptor subtypes were decreased in distal mesenteric arteries, compared with normal rats. CONCLUSIONS: There was the gender-related functional difference of α(1)-adrenoceptors in normal rats. In both male and female rats, diabetes decreased the contractile response in mesenteric arteries, which might be caused by the overall change in α(1)-adrenoceptor.

The effect of low fresh gas flow rate on sevoflurane consumption.

BACKGROUND: In an era of medical cost containment, cost-effectiveness has become a major focus in healthcare. The effect of a new policy on the use of low fresh gas flow during maintenance of general anesthesia with volatile anesthetics was evaluated. METHODS: The numbers and duration of general anesthesia cases using sevoflurane 5 weeks prior to and 15 weeks after policy implementation were retrieved from the electronic medical records database. The number of sevoflurane bottles consumed was also assessed. The anesthesia hours per bottle of sevoflurane were compared before and after policy implementation. RESULTS: The number of anesthesia hours performed per bottle of sevoflurane increased by 38.3%. The effect varied over time and tended to fade with time. CONCLUSIONS: The implementation of a low fresh gas flow rate policy effectively reduces the amount of sevoflurane consumed for the same duration of anesthesia.

Perioperative cerebral infarct during cardiac surgery and changes in jugular venous O2 saturation and cerebral oximetry using near-infrared spectroscopy: A case report.

Despite reductions in surgical mortality, neurologic sequelae remain a devastating complication after cardiac surgery with cardiopulmonary bypass. Neurologic complications may be induced by a massive air embolism during cardiopulmonary bypass, even with extensive monitoring. This report describes a patient who had a fatal cerebral infarct during aortic valve and ascending aorta replacement surgery. We monitored jugular venous O2 saturation (SjvO2) and cerebral oximetry using near-infrared spectroscopy in the perioperative period. The operation and anesthesia were uneventful until the deep hypothermic total arrest for the replacement of the ascending aorta. However, restarting the cardiopulmonary bypass after deep hypothermic total arrest produced a brief (less than 10 seconds) but large amount of air in the root cannula. At this time, although cerebral oximetry did not show any changes, the SjvO2 decreased to 21% for about 3 minutes and then normalized. At 8 hours after surgery, the patient showed seizures and severe edema in both cerebral hemispheres on the MRI. The patient died 21 days after surgery.

Effect of vasopressin on survival of Purkinje neurons in rat cerebellar slices after an in vitro simulated ischemia.

BACKGROUND: Arginine vasopressin (AVP) is frequently used in patients under the risk of brain injury. It has been shown to induce brain injury after ischemia and reperfusion in in vivo animal models. We determined the effect of vasopressin on the brain injury after ischemia-reperfusion using in vitro model. METHODS: Cerebellar brain slices were prepared from adult Sprague-Dawley rats. They were then subjected to simulated ischemia (oxygen-glucose deprivation) for 20 min in the absence (control) or presence of vasopressin (5, 10, 50, 100, 500 pg/ml). After being recovered in oxygenated artificial cerebrospinal fluid for 5 h, they were fixed for morphologic examination to determine the percentage of live Purkinje cells. RESULTS: There were no differences in the survival rate of Purkinje cells among the control and vasopressin groups. CONCLUSIONS: Vasopressin at concentrations studied has no direct effect on brain ischemia-reperfusion injury.