Comparison of preoxygenation efficiency measured by the oxygen reserve index between high-flow nasal oxygenation and facemask ventilation: a randomised controlled trial.

BACKGROUND: High-flow nasal oxygenation and the oxygen reserve index (ORI), which is a non-invasive and innovative modality that reflects the arterial oxygen content, are used in general anaesthesia. This study compares the preoxygenation efficiency (measured by the ORI) of high-flow nasal oxygenation and facemask ventilation during the induction process. METHODS: This single-centre, two-group, randomised controlled trial included 197 patients aged ≥ 20 years who underwent orotracheal intubation for general anaesthesia for elective surgery. The patients were randomly allocated to receive preoxygenation via facemask ventilation or high-flow nasal oxygenation. The ORI was measured and compared between both groups. RESULTS: The ORI increased during preoxygenation in all patients. At 1 min of preoxygenation, the ORI was significantly higher in the high-flow nasal oxygenation group (0.34 ± 0.33) than in the facemask ventilation group (0.21 ± 0.28; P = 0.003). The highest ORI was not significantly different between the two groups (0.68 ± 0.25 in the high-flow nasal oxygenation group vs. 0.70 ± 0.28 in the facemask ventilation group; P = 0.505). CONCLUSIONS: High-flow nasal oxygenation results in an oxygenation status similar to that provided by facemask ventilation during the induction process of general anaesthesia; therefore, high-flow nasal oxygenation is a feasible preoxygenation method. TRIAL REGISTRATION: Clinicaltrials.gov (NCT04291339).

A novel electromagnetic guidance ultrasound system on radial artery cannulation: a prospective randomized controlled trial.

BACKGROUND: Radial artery cannulation can cause complications such as haematoma formation or thrombosis due to its small diameter. Recently, a novel ultrasound device equipped with an electromagnetic guidance system was introduced, showing the path and alignment of the needle during the procedure. The aim of this study was to investigate the effects of this novel system on both success and complication rates during radial artery cannulation under ultrasound guidance. METHODS: In this randomized controlled trial, 76 adults scheduled for neurosurgery requiring radial artery cannulation were recruited. In group E (n = 38), radial artery cannulation was performed using the electromagnetic guidance ultrasound system, whereas in group C (n = 38), the procedure was performed using conventional ultrasound guidance. The success rates of cannulation on the first attempt, cannulation times, number of attempts, and incidence of complications were compared between the two groups. RESULTS: There was a significant difference in the success rates on the first attempt between the two groups (group C = 78.9% vs. group E = 94.7%, P = 0.042). Incidences of posterior wall puncture and haematoma formation (group C = 8 vs. group E = 1; P = 0.028) were significantly lower in group E than in group C. The median cannulation time for successful attempts was comparable between groups. CONCLUSIONS: Use of the novel electromagnetic guidance system resulted in a better success rate on the first attempt and a lower incidence of complications during radial artery cannulation. TRIAL REGISTRATION: This study was registered at http://cris.nih.go.kr (registration number: KCT0002476 ).

The effect of oxygen concentration on atelectasis formation during induction of general anesthesia in children: A prospective randomized controlled trial.

BACKGROUND: In adults, the use of lower oxygen concentration during induction is associated with less atelectasis formation without an increase in incidence of hypoxia. However, it is unknown whether this remains true in the pediatric patients. METHODS: Fifty-four pediatric patients who were scheduled to undergo elective lower abdominal surgery were randomized to one of three oxygenation groups: 100%, 80%, or 60% oxygen (in air). During anesthesia induction, patients were ventilated with sevoflurane in 100%, 80%, or 60% oxygen. Endotracheal intubation and mechanical ventilation were performed. Atelectasis was diagnosed using LUS, which was performed after anesthetic induction and at the end of surgery. RESULTS: We assessed atelectasis after anesthetic induction and at the end of surgery. After anesthetic induction, the number of atelectatic lung regions was significantly different among the three groups (median [IQR], 2.0 [1.0-2.5], 2.0 [1.0-2.8], and 3.0 [2.0-3.0] in the 60%, 80%, and 100% oxygen groups, p = .033) and between the 60% and 100% groups (p = .015), but not between 80% and 100% groups (p = .074). However, no differences in the number of atelectatic lung regions were found among the three groups at the end of surgery (2.0 [1.3-3.8], 3.0 [1.8-3.0], and 4.0 [2.0-4.0] in the 60%, 80%, and 100% oxygen groups; p = .169). CONCLUSION: Lower oxygen concentration during anesthetic induction is associated with less atelectasis formation immediately after anesthetic induction in children. In addition, applying 80% oxygen instead of 100% oxygen is not enough to prevent atelectasis formation, and 60% oxygen should be applied to prevent atelectasis. However, this effect does not last until the end of surgery.

Safety and Efficacy of Off-label and Unlicensed Medicines in Children.

BACKGROUND: The aim of this study was to explore the use of off-label/unlicensed drugs to confirm the safety and efficacy of their prescription in children in Korea. METHODS: In this retrospective study, we analyzed data of patients who received any of the 32 drugs between January-December 2014 in tertiary hospitals in Korea, including demographics, diagnoses, reasons for the medication, administration route, and details of adverse drug reactions. Additionally, the mortality in the cohort was assessed. The primary outcomes were efficacy and safety, including mortality, of these drugs in pediatric patients. The secondary outcomes were the current statuses of the use of off-label/unlicensed drugs in two centers. RESULTS: Totally, 5,130 prescriptions were found in 2,779 patients. Age (73.5%) and indication (11.7%) were the most frequent reasons for prescriptions being off-labeled/unlicensed. Approximately 88% of the prescriptions were effective, and 19% of the patients developed adverse drug reactions. The number of prescriptions was significantly higher in children with adverse drug reactions than it was in those without (2.8 vs. 1.5; P < 0.001). The number of prescribed off-label/unlicensed medicines and age at prescription were independently associated with adverse drug events (odds ratio, 1.55 and 1.1; P < 0.001 and 0.034, respectively). CONCLUSION: Children are still prescribed medicines that are not authorized in terms of age, weight, indications, or routes of administration. Therefore, many old products require re-assessment of authorization. More prospective clinical studies should be performed to confirm the efficacy and safety of drugs in the pediatric population.

Dexmedetomidine Inhibits Phenylephrine-induced Contractions via Alpha-1 Adrenoceptor Blockade and Nitric Oxide Release in Isolated Rat Aortae.

The goal of this in vitro study was to examine the effect of the alpha-2 adrenoceptor agonist dexmedetomidine on phenylephrine (alpha-1 adrenoceptor agonist)-induced contraction in isolated rat aortae and to elucidate the associated cellular mechanisms, with a particular focus on alpha-1 adrenoceptor antagonism. Dexmedetomidine dose-response curves were generated in isolated endothelium-intact and endothelium-denuded rat aortae precontracted with phenylephrine or 5-hydroxytryptamine. Endothelium-denuded aortic rings were pretreated with either dexmedetomidine or the reversible alpha-1 adrenoceptor antagonist phentolamine, followed by post-treatment with the irreversible alpha-1 adrenoceptor blocker phenoxybenzamine. Control rings were treated with phenoxybenzamine alone. All rings were repeatedly washed with Krebs solution to remove all pretreatment drugs, including phenoxybenzamine, phentolamine and dexmedetomidine. Phenylephrine dose-response curves were then generated. The effect of rauwolscine on the dexmedetomidine-mediated change in phenylephrine-induced endothelial nitric oxide synthase (eNOS) phosphorylation in human umbilical vein endothelial cells was examined using western blotting. The magnitude of the dexmedetomidine-mediated inhibition of phenylephrine-induced contraction was higher in endothelium-intact aortae than in endothelium-denuded aortae or endothelium-intact aortae treated with Nω-nitro-L-arginine methyl ester. However, dexmedetomidine did not significantly alter 5-hydroxytryptamine-induced contraction. In further experiments, prazosin attenuated dexmedetomidine-induced contraction. Additionally, pretreatment with either dexmedetomidine plus phenoxybenzamine or phentolamine plus phenoxybenzamine produced greater phenylephrine-induced contraction than phenoxybenzamine alone, suggesting that dexmedetomidine protects aortae from the alpha-1 adrenoceptor blockade induced by phenoxybenzamine. Rauwolscine attenuated the dexmedetomidine-mediated enhancement of phenylephrine-induced eNOS phosphorylation. Taken together, these results suggest that dexmedetomidine attenuates phenylephrine-induced contractions via alpha-1 adrenoceptor blockade and endothelial nitric oxide release in the isolated rat aorta.

Measuring the depth of the caudal epidural space to prevent dural sac puncture during caudal block in children.

BACKGROUND: Caudal blocks are performed through the sacral hiatus in order to provide pain control in children undergoing lower abdominal surgery. During the block, it is important to avoid advancing the needle beyond the sacrococcygeal ligament too much to prevent unintended dural puncture. This study used demographic data to establish simple guidelines for predicting a safe needle depth in the caudal epidural space in children. METHODS: A total of 141 children under 12 years old who had undergone lumbar-sacral magnetic resonance imaging were included. The T2 sagittal image that provided the best view of the sacrococcygeal membrane and the dural sac was chosen. We used Picture Achieving and Communication System (Centricity® PACS, GE Healthcare Co.) to measure the distance between the sacrococcygeal ligament and the dural sac, the length of the sacrococcygeal ligament, and the maximum depth of the caudal space. RESULTS: There were strong correlations between age, weight, height, and BSA, and the distance between the sacrococcygeal ligament and dural sac, as well as the length of the sacrococcygeal ligament. Based on these findings, a simple formula to calculate the distance between the sacrococcygeal ligament and dural sac was developed: 25 × BSA (mm). CONCLUSION: This simple formula can accurately calculate the safe depth of the caudal epidural space to prevent unintended dural puncture during caudal block in children. However, further clinical studies based on this formula are needed to substantiate its utility.

Determination of the optimal depth of a left internal jugular venous catheter in infants: A prospective observational study.

BACKGROUND: Few reports exist regarding the optimal depth of a left-sided central venous catheter in pediatric patients. We aimed to provide a guideline for the optimal depth of central venous catheters at the left internal jugular vein in infants, using anatomical landmarks, age, height, and weight. METHODS: A two-stage study was conducted. In the first observational study, infants aged ≤1 year and scheduled for elective surgery requiring a central venous catheter were enrolled. The tip of the central venous catheter was confirmed using transthoracic echocardiography. Linear regression modeling was performed to determine the association between the insertion depth of the central venous catheter and the I-A-B distance (I, the insertion point; A, the sternal head of the left clavicle; B, the midpoint of the perpendicular line drawn between the sternal head of the right clavicle and an imaginary line between the nipples), based on age, height, and weight. In the second study, the results of the first study were validated in another group of consecutive infants. RESULTS: In the first study, the data of 67 patients were analyzed. The infant's height and I-A-B distance were highly correlated with the level of the central venous catheter tip (R2 =0.763 and 0.772, respectively; all P < .01), using the regression equations 0.11 ×  height (cm) + 0.19 and 1.02 ×  I-A-B (cm) + 1.55, respectively. In the second study, height was also highly correlated with the insertion depth of the central venous catheter in another 42 infants (r = .938, P = <.001). In a Bland-Altman's analysis, the mean bias and precision of the actual insertion depth and predicted depth using height were 0.09 and 0.15 cm, respectively. The limits of agreement were -0.19 and 0.38 cm, respectively. CONCLUSION: In infants, the optimal depth of a central venous catheter at the left internal jugular vein can be determined with a simple formula using height.

Lipid Emulsion Inhibits Vasodilation Induced by a Toxic Dose of Bupivacaine via Attenuated Dephosphorylation of Myosin Phosphatase Target Subunit 1 in Isolated Rat Aorta.

Lipid emulsions are widely used for the treatment of systemic toxicity that arises from local anesthetics. The goal of this in vitro study was to examine the cellular mechanism associated with the lipid emulsion-mediated attenuation of vasodilation induced by a toxic dose of bupivacaine in isolated endothelium-denuded rat aorta. The effects of lipid emulsion on vasodilation induced by bupivacaine, mepivacaine, and verapamil were assessed in isolated aorta precontracted with phenylephrine, the Rho kinase stimulant NaF, and the protein kinase C activator phorbol 12,13-dibutyrate (PDBu). The effects of Rho kinase inhibitor Y-27632 on contraction induced by phenylephrine or NaF were assessed. The effects of bupivacaine on intracellular calcium concentrations ([Ca(2+)]i) and tension induced by NaF were simultaneously measured. The effects of bupivacaine alone and lipid emulsion plus bupivacaine on myosin phosphatase target subunit 1 (MYPT1) phosphorylation induced by NaF were examined in rat aortic vascular smooth muscle cells. In precontracted aorta, the lipid emulsion attenuated bupivacaine-induced vasodilation but had no effect on mepivacaine-induced vasodilation. Y-27632 attenuated contraction induced by either phenylephrine or NaF. The lipid emulsion attenuated verapamil-induced vasodilation. Compared with phenylephrine-induced precontracted aorta, bupivacaine-induced vasodilation was slightly attenuated in NaF-induced precontracted aorta. The magnitude of the bupivacaine-induced vasodilation was higher than that of a bupivacaine-induced decrease in [Ca(2+)]i. Bupivacaine attenuated NaF-induced MYPT1 phosphorylation, whereas lipid emulsion pretreatment attenuated the bupivacaine-induced inhibition of MYPT1 phosphorylation induced by NaF. Taken together, these results suggest that lipid emulsions attenuate bupivacaine-induced vasodilation via the attenuation of inhibition of MYPT1 phosphorylation evoked by NaF.

Appropriate dose of dexmedetomidine for the prevention of emergence agitation after desflurane anesthesia for tonsillectomy or adenoidectomy in children: up and down sequential allocation.

BACKGROUND: Dexmedetomidine can be used for the prevention of emergence agitation (EA) in children. However, an inadequate dose of dexmedetomidine can induce prolonged sedation and cardiovascular complications. The aim of this study was to evaluate the effective dose of dexmedetomidine for the prevention of EA after desflurane anesthesia for patients undergoing a tonsillectomy or adenoidectomy. METHODS: We enrolled 21 unpremedicated children, between 2 and 12 years, undergoing either a tonsillectomy or an adenoidectomy. General anesthesia was induced using sevoflurane and oxygen, and dexmedetomidine was administered before surgery. Anesthesia was maintained using desflurane resulting in a BIS range of 40-60. In the postanesthetic care unit (PACU), EA (agitation measured at level 4 or more at least once) was assessed on arrival in the PACU,15 min later, and 30 min later. The dose of dexmedetomidine for consecutive patients was determined by the response of the previous patient, using an increment or decrement of 0.1 µg/kg. RESULTS: The 50% effective dose of dexmedetomidine for prevention of EA was 0.25 µg/kg (95% confidence limits, 0.17-0.33 µg/kg), and the 95% effective dose was 0.38 µg/kg (95% confidence limits, 0.29-0.39 µg/kg). CONCLUSIONS: For prevention of EA after desflurane anesthesia for 50% and 95% of children undergoing tonsillectomies or adenoidectomies, 0.25 µg/kg or 0.38 µg/kg of dexmedetomidine is suggested. Further study is needed to validate the suggested dose of dexmedetomidine to prevent the EA that was identified in the present study. TRIAL REGISTRATION: Clinical Research Information Service KCT0000126 .

Population pharmacokinetic and pharmacodynamic model of propofol externally validated in children.

There have been no pharmacokinetic parameters and blood-brain equilibration rate constant (k e0) of propofol obtained in a single population of children, by which propofol can be administered using a target effect-site concentration controlled infusion. Thirty-nine, American Society of Anesthesiologists Physical Status 1-2 children aged 2-12 years were given an intravenous bolus of propofol (3 mg kg(-1)), followed by infusion (200 µg kg(-1) min(-1)). Arterial drug concentrations and bispectral index (BIS) values were measured. Population pharmacokinetic and pharmacodynamic analysis was performed using nonlinear mixed effects modeling. External model validation was performed in a separate population of children. A two-compartment model and a sigmoid E max model directly linked by an effect compartment well described the time courses of propofol concentration and BIS. The estimates of parameters were: V 1 (L) = 1.69, V 2 (L) = 27.2 + 0.929 × (weight - 25), Cl (L min(-1)) = 0.893 × (weight/23.6)(0.966), Q (L min(-1)) = 1.3; E 0 = 76.9; E max = 35.4, Ce 50 (µg mL(-1)) = 3.47 - (0.095 × age) - (1.63 × mean infusion rate of remifentanil in µg kg(-1) min(-1)); γ = 2.1; and k e0 (min(-1)) = 0.371. Pooled biases (95 % CI) of the target effect-site concentration controlled infusion system of propofol was -20.2 % (-23.3 to -18.1 %) and pooled inaccuracy was 30.4 % (28.6-32.7 %). Pooled biases of BIS prediction was -6.8 % (-9.1 to -4.1 %) and pooled inaccuracies was 19.1 % (17.5-20.9 %).The altered weight-based dose requirements of propofol are well described pharmacokinetically, and pharmacodynamically. Predictive performances of the TCI system in this study were clinically acceptable.

Dexmedetomidine-induced contraction involves c-Jun NH2 -terminal kinase phosphorylation through activation of the 5-lipoxygenase pathway in the isolated endothelium-denuded rat aorta.

Vasoconstriction induced by dexmedetomidine, a highly selective alpha-2 adrenoceptor agonist, mainly involves c-Jun NH2 -terminal kinase (JNK) phosphorylation in the isolated endothelium-denuded aorta. We carried out an in vitro study to determine the main arachidonic acid metabolic pathway that is involved in dexmedetomidine-induced JNK activation. Cumulative dexmedetomidine concentration-contractile response curves were generated in the endothelium-denuded rat aorta in the presence or absence of the following inhibitors: the JNK inhibitor SP600125, the phospholipase A2 inhibitor quinacrine dihydrochloride, the non-specific lipoxygenase (LOX) inhibitor nordihydroguaiaretic acid, the 5-LOX inhibitor AA-861, the dual 5-LOX and cyclooxygenase (COX) inhibitor phenidone, the non-specific COX inhibitor indomethacin, the cytochrome p450 epoxygenase inhibitor fluconazole, the COX-1 inhibitor SC-560, and the COX-2 inhibitor NS-398. The effect of the alpha-2 adrenoceptor inhibitor rauwolscine and other inhibitors, such as quinacrine dihydrochloride, nordihydroguaiaretic acid, AA-861, phenidone, indomethacin and the protein kinase C inhibitor GF 109203X, on dexmedetomidine-induced JNK phosphorylation was investigated in rat aortic vascular smooth muscle cells with western blotting. The effect of dexmedetomidine on 5-LOX and COX-2 expression was investigated in vascular smooth muscle cells. SP600125, quinacrine dihydrochloride, nordihydroguaiaretic acid, AA-861, phenidone, rauwolscine and chelerythrine attenuated dexmedetomidine-induced contraction. Indomethacin slightly attenuated dexmedetomidine-induced contraction. Fluconazole and SC-560 had no effect on dexmedetomidine-induced contraction, whereas NS-398 attenuated contraction. SP600125, rauwolscine, quinacrine dihydrochloride, nordihydroguaiaretic acid, AA-861, phenidone and GF 109203X attenuated dexmedetomidine-induced JNK phosphorylation. 5-LOX and COX-2 were upregulated by dexmedetomidine. Thus, dexmedetomidine-induced alpha-2 adrenoceptor-mediated contraction is mediated mainly by 5-LOX and partially by COX-2, which leads to JNK phosphorylation.

Transthoracic echocardiographic guidance for obtaining an optimal insertion length of internal jugular venous catheters in infants.

BACKGROUND: There are multiple methods of determining the optimal position of central venous catheter (CVC) tips. The purpose of this study was to assess the feasibility of transthoracic echocardiography (TTE), and compare TTE and height-based method for correct positioning of CVCs in infants undergoing cardiac surgery. METHODS: Ultrasonography-guided central venous catheterization was performed via the right internal jugular vein. Longitudinal images of the right atrium and superior vena cava were obtained using TTE. The catheter tip was located 10 mm above the crista terminalis. If the catheter tip was not clearly visualized, the probe was rotated to obtain transverse images and the CVC tip was positioned at the level of the pulmonary artery bifurcation. The mean distance from the catheter tip to the level of the carina was compared with that calculated using a height-based formula. RESULTS: Among 106 cases, positioning of the CVC tip under TTE guidance failed in four patients; thus, the success rate was 96.2%. The mean distance from the CVC tip to the level of the carina was different for positioning using the TTE method (-3.8 ± 8.2 mm; 95% confidence interval, -5.5 to -2.2 mm) and that using the height-based formula (6.1 ± 9.6 mm; 95% CI, 4.2 to 8.0 mm; P = 0.001). The distance was consistent regardless of the height when the insertion length was determined using TTE (r = -0.048, P > 0.05). CONCLUSIONS: Transthoracic echocardiography is a practical method for the correct placement of the CVC tip with less variability compared to the height-based method.

Associations between Clinicopathological Characteristics and Intraoperative Opioid Requirements during Endoscopic Submucosal Dissection with Monitored Anesthesia Care: A Retrospective Study.

Background and study aims: Endoscopic submucosal dissection is used to treat early gastric neoplasms. Compared with other endoscopic procedures, it requires higher doses of opioids, leading to adverse events during monitored anesthesia care. We investigated the correlations between clinicopathological characteristics and intraprocedural opioid requirements in patients who underwent endoscopic submucosal dissection under monitored anesthesia care. Patients and methods: The medical records of patients who underwent endoscopic submucosal dissection under monitored anesthesia care were retrospectively reviewed. The dependent variable was the total dose of fentanyl administered during the dissection, while independent variables were patient demographics, the American Society of Anesthesiologists physical status classification, preoperative vital sign data, and the pathological characteristics of the neoplasm. Correlations between variables were examined using multiple regression analysis. Results: The study included 743 patients. The median total fentanyl dose was 100 mcg. Younger age (coefficient -1.37; 95% confidence interval [CI] -1.78 to -0.95), male sex (16.12; 95% CI 6.99-25.24), baseline diastolic blood pressure (0.44; 95% CI 0.04-0.85), neoplasm length (1.63; 95% CI 0.90-2.36), and fibrosis (28.59; 95% CI 17.77-39.42) were positively correlated with the total fentanyl dose. Total fentanyl dose was higher in the differentiated (16.37; 95% CI 6.40-26.35) and undifferentiated cancers group (32.53; 95% CI 16.95-48.11) than in the dysplasia group; no significant differences were observed among the others. The mid-anterior wall (22.69; 95% CI 1.25-44.13), mid-posterior wall (29.65; 95% CI 14.39-44.91), mid-greater curvature (28.77; 95% CI 8.56-48.98), and upper groups (30.06; 95% CI 5.01-55.12) had higher total fentanyl doses than the lower group, whereas doses did not significantly differ for the mid-lesser curvature group. Conclusions: We identified variables that influenced opioid requirements during monitored anesthesia care for endoscopic submucosal dissection. These may help predict the needed opioid doses and identify factors affecting intraprocedural opioid requirements.

A comparative trial of the GlideScope(R) video laryngoscope to direct laryngoscope in children with difficult direct laryngoscopy and an evaluation of the effect of blade size.

BACKGROUND: GlideScope® video laryngoscope (GVL) has been proposed to be useful for airway management, but its efficacy for difficult airways has not been confirmed in pediatric patients. In this study, we evaluated the usefulness of the GVL for improving the laryngoscopic view in patients whose Cormack and Lehane grade (C&L grade) was ≥3 under direct laryngoscopy. We also assessed the effect of GVL blade size on the laryngoscopic view. METHODS: This randomized open trial was conducted in a tertiary pediatric center. Patients whose previous C&L grade was ≥3, or who were anticipated to have a difficult airway, were enrolled. The initial modified C&L grade was scored using a direct laryngoscope (DL). If the patient's C&L grade was ≥3, the laryngoscopic view was scored again using GVLw (selected based on weight) and GVLs (1 size smaller than GVLw) in random order by a single experienced anesthesiologist. All laryngoscopic views were graded both with and without the backward, upward, and right lateral displacement of the thyroid cartilage (BURP) maneuver. The primary outcome was the difference in the C&L grade between DL and GVLw, and the secondary outcome was that between GVLw and GVLs. For statistical analysis, the modified C&L grade was converted to an ordinal scale. RESULTS: Data from 23 pediatric patients were analyzed. When compared with DL, improvement of laryngoscopic view with the GVLw wa not obvious (98.3% confidence interval [CI] for differences of ordinal scale, 0-1 without BURP, P = 0.15 and 0-1 with BURP, P = 0.11). However, GVLs improved the laryngoscopic view in comparison with both DL (98.3% CI for differences, 3.5-5.0 without BURP, P = 0.00007 and 3.5-4.5 with BURP, P = 0.0001) and GVLw (98.3% CI for differences, 3.0-4.5 without BURP, P = 0.00007 and 2.5-4.0 with BURP, P = 0.0001). There was no adverse outcome during this study. CONCLUSIONS: In patients with C&L grade ≥3 under direct laryngoscopy, GVLs significantly improved the laryngoscopic view when compared with DL or GVLw. The GVLs is recommended for improving the laryngoscopic view in patients with a difficult airway.

The effect of full expiration on the position and size of the subclavian vein in spontaneously breathing adults.

BACKGROUND: If full expiration during subclavian venous cannulation increases the distance between the subclavian vein (SCV) and the pleura or increases the diameter of the vein, it might decrease the incidence of pneumothorax and/or increase the success rate of venous cannulation. In this study, we evaluated the effect of full expiration on the distance from the SCV to the pleura and on the crosssectional area (CSA) of the SCV in spontaneously breathing adults. METHODS: The distance from the inferior border of the right SCV and the pleura (SCVinf-Pleura distance), the distance from the center of the vein to the pleura (SCVcen-Pleura distance), and the CSA of the vein were measured using ultrasound at the end of inspiration and at the end of full expiration in 20 adults placed in the horizontal position. The subjects were then placed in 15° Trendelenburg tilt, and the distances and the CSA were measured again. RESULTS: The SCVcen-Pleura distances were changed minimally in the horizontal position (0.005 cm, 95% confidence interval [CI] -0.04 to 0.05) and in the Trendelenburg position (0.02 cm, 95% CI -0.005 to 0.05). The SCVinfPleura distances decreased at the end of full expiration in the horizontal position, but the change was only 0.07 cm (95% CI 0.03-0.11; P = 0.003). In the Trendelenburg position, those distances remained unchanged (0.02 cm, 95% CI -0.01 to 0.06). Compared with endinspiration, the SCV CSA after full expiration increased by at least 14% in both the horizontal position and the Trendelenburg position. CONCLUSIONS: The distance from the SCV to the pleura did not change after full expiration. However, this simple technique can still be considered during placement of subclavian catheters in spontaneously breathing patients, because it significantly enlarges the CSA of the SCV.

Comparison of the efficacy of ramosetron and ondansetron in the prophylaxis of postoperative vomiting in children receiving fentanyl by patient-controlled analgesia after orthopedic surgery: a randomized controlled trial.

BACKGROUND: This study was designed to compare the efficacy of prophylactic ramosetron and ondansetron in preventing postoperative vomiting in children who received fentanyl by patient-controlled analgesia after orthopedic surgery. METHODS: Two hundred and eighteen children, 2-15 years old, ASA physical status 1 or 2, scheduled for elective orthopedic surgeries, were randomly divided into the ramosetron group (n = 109) or ondansetron group (n = 109). Patients in ondansetron group received ondansetron 100 µg·kg(-1) and patients in ramosetron group received ramosetron 6 µg·kg(-1) after surgery. Intravenous patient-controlled analgesia with fentanyl was used in both groups. The incidence of postoperative vomiting and side effects were assessed during the 48 h after surgery. RESULTS: There was significantly less vomiting during the first 24-h and 6-24-h period after surgery in ramosetron group than in ondansetron group (P < 0.01). There were no significant differences in side effect of 5-HT(3) antagonist between the two groups. CONCLUSION: Ramosetron was more effective during the first 24-h period after surgery than ondansetron in children using fentanyl patient-controlled analgesia after general anesthesia.

The accuracy of noninvasive hemoglobin monitoring using the radical-7 pulse CO-Oximeter in children undergoing neurosurgery.

BACKGROUND: The most common method for determining the hemoglobin concentration is to draw blood from a patient. However, the Radical-7 Pulse CO-Oximeter (Masimo Corporation, Irvine, CA) can noninvasively provide continuous hemoglobin concentration (SpHb). In our study we compared noninvasive measurements of SpHb with simultaneous laboratory measurements of total hemoglobin in arterial blood samples taken from children (tHb). METHODS: Arterial blood samples were analyzed using a laboratory CO-oximeter, and SpHb was simultaneously recorded in pediatric patients undergoing neurosurgery. When patients met the criteria for hypovolemia, 10 mL/kg of colloids or red blood cells were administered over 10 minutes. SpHb and tHb data were collected before and after intravascular volume resuscitation. The relationship between SpHb and tHb was assessed using a 4-quadrant plot, linear regression, mixed-effect model, and modified Bland-Altman analyses. RESULTS: One hundred nineteen paired samples were analyzed. The correlation coefficient between SpHb and tHb was 0.53 (P < 0.001), whereas that of change in SpHb versus change in tHb was 0.75 (P < 0.001). The average difference (bias) between tHb and SpHb was 0.90 g/dL (95% confidence interval [CI], 0.48-1.32 g/dL) and 1 standard deviation of the difference (sd) was 1.35 g/dL. The concordance rate (a measure of the number of data points that are in 1 of the 2 quadrants of agreement) determined using a 4-quadrant plot was 93%. The correlation coefficient between SpHb and tHb after intravascular volume resuscitation was 0.58 (P < 0.001), whereas that of changes in SpHb and tHb was 0.87 (P < 0.001). The bias immediately after volume resuscitation was 1.18 g/dL (95% CI, 0.81-1.55 g/dL), and sd was 1.28 g/dL with a concordance rate of 94.4%. The bias was -0.03 g/dL when tHb was ≥11 g/dL, which was significantly lower in comparison with biases when tHb <9 g/dL (1.24 g/dL) and tHb was 9-11 g/dL (1.17 g/dL) (P = 0.004). CONCLUSION: The Radical-7 Pulse CO-Oximeter can be useful as a trend monitor in children during surgery even immediately after intravascular volume expanders are administered. However, it is advisable to confirm the baseline hemoglobin level and to consider the influence of tHb level on the bias. In addition, one should be cautious with regard to using SpHb alone when making transfusion decisions.

Intraoperative plasma lactate as an early indicator of major postoperative events in pediatric cardiac patients.

Hyperlactatemia and unmeasured anions (UMA) have been suggested to be useful predictors of outcomes after pediatric cardiac surgery in the ICU. However, if we detect high-risk patient in the operating room, we could practice early intervention to decrease mortality and morbidity. The purpose of this study was to determine whether the intraoperative lactate or UMA levels can predict adverse outcomes in pediatric cardiac patients with undergoing cardiopulmonary bypass (CPB). We studied 102 patients with congenital heart disease. Arterial blood samples were obtained after inducing anesthesia, 5 min after weaning from CPB and after chest closure. Major adverse events (MAEs) were defined as cardiac compression, re-sternotomy due to hemodynamic instability, extra-corporeal membrane oxygenator support, creatinine levels greater than 2 mg/dL, or death. Patients were divided into MAE group (8 patients, 7.8%) and non-MAE group. Six patients with MAEs died. Importantly, the lactate levels (mmol/L) at weaning from CPB (4.19 vs 2.1; MAE group vs non-MAE group), chest closure (5.76 vs 2.39; MAE group vs non-MAE group) and the intraoperative increases in lactate levels were significantly higher in the MAE group than in the non-MAE group. However, there was no significant difference in the UMA levels or their changes between the groups. The increase in the lactate level from CPB weaning to chest closure was the best predictor of MAEs (AUC: 0.810). In conclusion, the intraoperative plasma lactate levels were more closely associated with MAEs, and they are more useful for predicting the outcome of pediatric cardiac patients than the UMA levels.

Comparison of the antiemetic effect of ramosetron and combined ramosetron and midazolam in children: a double-blind, randomised clinical trial.

CONTEXT: Postoperative nausea and vomiting remains a clinically important problem after strabismus surgery in children. OBJECTIVE: To study the benefit of adding midazolam to ramosetron on the incidence of postoperative nausea, retching or vomiting and on the incidence of postoperative agitation. DESIGN: A randomised, double-blind comparison. SETTING: The operating theatre suite and day care unit of Seoul National University Hospital. The study period was January to December 2010. PATIENTS: In total, 405 paediatric patients (aged 4-12 years) undergoing strabismus surgery were enrolled and randomly assigned to one of two groups, ramosetron or ramosetron with midazolam. INTERVENTION: Patients received either ramosetron 6 µg kg or ramosetron 6 µg kg and midazolam 0.1 mg kg prior to induction of anaesthesia. MAIN OUTCOME MEASURES: The incidences of nausea, retching or vomiting in the first 48 h after surgery, and the incidence of emergence agitation in the post-anaesthetic care unit. RESULT: The incidences of nausea, retching or vomiting during the first and second 24-h periods after surgery were similar in the two groups. There was a small, clinically insignificant reduction in delirium scores in the ramosetron with midazolam group. CONCLUSION: Adding midazolam to ramosetron had no advantages over ramosetron alone in reducing the incidence of postoperative nausea and vomiting in children undergoing strabismus surgery.

A Novel Propofol Dosing Regimen for Pediatric Sedation during Radiologic Tests.

The dose of propofol for pediatric sedation during radiologic tests has been proposed as an equation of 0.75 + 0.14 × age (months) + 45.82 × body surface area (m2) based on results in a previous study. We compared this equation and the conventional dosing strategy for sedation in children undergoing radiologic tests. An amount of 180 children scheduled for magnetic resonance imaging (MRI) were randomized to experimental and control groups. The initial induction dose of propofol calculated using the equation was administered in the experimental group. In the control group, children received 1 mg/kg of the initial induction dose of propofol. Then, 0.5 mg/kg of the additional dose was followed to induce sedation in both groups. When awake or moving, a rescue injection of 0.5 mg/kg propofol was given. The total induction dose was more significant in the experimental group. The number of injections for induction in the experimental group was lesser. The dose and number of rescue injections in the experimental group were significantly less. The equation for the induction dose of propofol in a previous study could achieve quick induction of sedation and prevent a rescue injection during sedation. However, caution is needed when using the equation.