Cerebral regional oxygen saturation as a predictive parameter for preoperative heart failure and delayed hemodynamic recovery in transcutaneous aortic valve implantation: a retrospective cohort study.

This study aimed to investigate the relationship of perioperative cerebral regional oxygen saturation (rSO2) with various preoperative clinical variables and hemodynamic changes during transfemoral transcatheter aortic valve implantation (TAVI) under general anesthesia. We retrospectively analyzed cerebral rSO2 values from left-hemisphere measurements obtained using near-infrared spectroscopy (O3™ regional oximetry) at five time points: pre-induction, the start of the procedure, the start of valve deployment, time of lowest cerebral rSO2 value during valve deployment, and the end of the procedure. This study included 91 patients (60 with balloon-expandable valves and 31 with self-expandable valves). The baseline cerebral rSO2 values were correlated with B-type natriuretic peptide, hemoglobin, fractional shortening, ejection fraction, left ventricular mass index, left ventricular end-systolic diameter, STS risk of mortality, and STS morbidity or mortality. The patients who took longer to recover their systolic blood pressure to 90 mmHg after valve deployment with a balloon-expandable valve (group B) had lower cerebral rSO2 values during deployment compared to patients with faster recovery with balloon-expandable valve (group A) and with self-expandable valve (group C). Baseline cerebral rSO2 is associated with preoperative variables related to cardiac failure and function, and a significant decline during valve deployment may indicate a risk of prolonged hypotension during TAVI.

Separation of amyloid ß fragment peptides with racemised and isomerised aspartic acid residues using an original chiral resolution labeling reagent.

We developed a system to separate and identify racemised and isomerised aspartic acid (Asp) residues in amyloid ß (Aß) by labeling with an original chiral resolution labeling reagent, 1-fluoro-2,4-dinitrophenyl-5-D-leucine-N,N-dimethylethylenediamine-amide (D-FDLDA). The racemised and isomerised Asp residues labeled with D-FDLDA in Aß fragments generated by digesting with trypsin and endoproteinase Glu-C were separated and identified by liquid chromatography-mass spectrometry (LC-MS) under simple gradient conditions. Furthermore, the labeled Aß fragments did not aggregate and remained stable at least for 1 week at 4 °C.

Separation and Identification of Isoleucine Enantiomers and Diastereomers Using an Original Chiral Resolution Labeling Reagent.

D-Amino acids, which are present in small amounts in living organisms, are responsible for a variety of physiological functions. Some bioactive/biomolecular peptides also contain D-amino acids in their sequences; such peptides express different functions than peptides composed only of L-form amino acids. Among the 20 amino acids that make up proteins, threonine (Thr) and isoleucine (Ile) have two chiral carbons and thus have two enantiomers and diastereomers. These stereoisomers have been previously analyzed through HPLC using chiral columns or chiral resolution labeling reagents. However, the separation and identification of these stereoisomers are highly laborious and complicated. Herein, we propose an analytical method for the separation and identification of Ile stereoisomers through LC-MS using our original chiral resolution labeling reagent, 1-fluoro-2,4-dinitrophenyl-5-L-valine-N,N-dimethylethylenediamine-amide (L-FDVDA) and a PBr column packed with pentabromobenzyl-modified silica gel. Twenty DL-amino acids including Thr stereoisomers (41 amino acids including glycine) were separated and identified using C18 column. Ile stereoisomers could be separated using not a C18 column but a PBr column. Additionally, we showed that peptides containing Thr and Ile stereoisomers can be accurately detected through labeling with L-FDVDA.

Separation of nicotinamide metabolites using a PBr column packed with pentabromobenzyl group modified silica gel.

Nicotinamide adenine dinucleotide, a coenzyme involved in the activation of sirtuins, contributes to various regulations in vivo. However, highly hydrophilic nicotinamide metabolites are difficult to separate by high-performance liquid chromatography (HPLC) using octadecyl (C18) columns, which operate via hydrophobic interaction. PBr columns packed with silica gel modified with the pentabromobenzyl group having strong dispersion forces show good retention ability for various highly hydrophilic compounds. Additionally, the peak shape obtained with the PBr column did not collapse like that of the HILIC column, even when a large amount of water was injected. Separation of 11 highly hydrophilic nicotinamide metabolites using a PBr column under simple conditions resulted in baseline separation, but separation on a C18 column was not complete. The peak shape for each compound was better than that in previous studies. Furthermore, the separation of nicotinamide metabolites in tomato using a PBr column enable a more sensitive detection than that using a C18 column. SUBJECT CATEGORY: Chromatographic Technique.

Separation and identification of the DL-forms of short-chain peptides using a new chiral resolution labeling reagent.

There are several reports of D-amino acids being the causative molecules of serious diseases, resulting in the formation of, for example, prion protein and amyloid ß. D-Amino acids in peptides and proteins are typically identified by sequencing each residue by Edman degradation or by hydrolysis with hydrochloric acid for amino acid analysis. However, these approaches can result in racemization of the L-form to the D-form by hydrolysis and long pre-treatment for hydrolysis. To address these problems, we aimed to identify the DL-forms of amino acids in peptides without hydrolysis. Here, we showed that the DL-forms in peptides which are difficult to separate on a chiral column can be precisely separated by labeling with 1-fluoro-2,4-dinitrophenyl-5-D-leucine-N,N-dimethylethylenediamine-amide (D-FDLDA). Additionally, the peptides could be quantitatively analyzed using the same labeling method as for amino acids. Furthermore, the detection sensitivity of a sample labeled with D-FDLDA was higher than that of the conventional reagents Nα-(5-fluoro-2,4-dinitrophenyl)-L-alaninamide (L-FDAA) and Nα-(5-fluoro-2,4-dinitrophenyl)-L-leucinamide (L-FDLA) used in Marfey's method. The proposed method for identifying DL-forms of amino acids in peptides is a powerful tool for use in organic chemistry, biochemistry, and medical science.

Comparisons of the efficiency of respiratory rate monitoring devices and acoustic respiratory sound during endoscopic submucosal dissection.

During moderate sedation for gastrointestinal endoscopic submucosal dissection (ESD), monitoring of ventilatory function is recommended. We compared the following techniques of respiratory rate (RR) measurement with respiratory sound (RRa): capnography (RRc), thoracic impedance (RRi), and plethysmograph (RRp). This study enrolled patients aged ≥ 20 years who underwent esophageal (n = 19) and colorectal (n = 5) ESDs. RRc, RRi, RRp, and RRa were measured by Capnostream™ 20P, BSM-2300, Nellcor™ PM1000N, and Radical-7®, respectively. In total, 413 RR data were collected from the esophageal ESD group and 114 RR data were collected from the colorectal ESD group. Compared with RRa during colorectal ESD, that during esophageal ESD had larger bias [95% limit of agreement (LOA)] with RRc [1.9 (- 11.0-14.8) vs. - 0.4 (- 2.9-2.2)], RRi [9.4 (- 16.8-9.4) vs. - 1.5 (- 12.0-8.9)], and RRp [0.3 (- 5.7-6.4) vs. 0.2 (- 3.2-3.6)]. Of the correct RR values displayed during esophageal ESD, > 90% were measured as RRa and RRp. Moreover, RRc was a useful parameter during colorectal ESD. To maximize patient safety during ESD under sedation, endoscopists and medical staff should know the feature and principle of the devices used for RR measurement. During esophageal ESD, RRa and RRp may be a good parameter to detect bradypnea or apnea. RRc, RRa and RRp are useful for reliable during colorectal ESD.Trial registration UMIN-CTR (UMIN000025421).

Intraoperative panic attack in patients undergoing awake craniotomy: a retrospective analysis of risk factors.

PURPOSE: Intraoperative anxiety is the most common psychological response of the patient during awake craniotomy. Psychological stress can trigger patient decline, resulting in failed awake craniotomy and significantly poor outcomes. This study aimed to identify the risk factors for panic attack (PA) during awake craniotomies. METHODS: With the local ethics committee approval, we conducted a manual chart review of the medical record of patients who underwent consecutive awake craniotomies between November 1999 and October 2016 at Tokyo Women's Medical University. A total of 405 patients were identified and assigned to 2 groups based on the Diagnostic and Statistical Manual of Mental Disorders-V criteria: those that met the PA criteria (Group PA) and those that did not (Group non-PA). Patient characteristics and the incidence of the PA specifier were collected. The features of the two groups were statistically compared, and risk factors for PA occurrence were determined by regression analysis. RESULTS: Sixteen of 405 patients met the diagnostic criteria of PA. Patients' characteristics were not statistically different between the groups. Multivariate logistic regression showed that intraoperative anxiety (p = 0.0002) and age younger than 39 years (as opposed to age > = 39 years; p = 0.0328) were significantly associated with the occurrence of PA during awake craniotomy. CONCLUSIONS: For patients undergoing awake craniotomy, intraoperative anxiety and age younger than 39 years were considered risk factors of PA. As PA often necessitates conversion to general anesthesia, intensive perioperative psychological support and pain management are required to achieve patient satisfaction and the surgical goal of awake craniotomy.

Anesthetic management of a patient with a continuous-flow left ventricular assist device for video-assisted thoracoscopic surgery: a case report.

BACKGROUND: As patients with left ventricular assist device (LVAD) have long expected survival, the incidence of noncardiac surgery in this patient population is increasing. Here, we present the anesthetic management of a patient with a continuous-flow LVAD who underwent video-assisted thoracic surgery (VATS). CASE PRESENTATION: A 37-year-old man with LVAD was scheduled to undergo VATS because of repeated spontaneous pneumothorax. Generally, patients with these devices have marginal right heart function; therefore, it is important to avoid factors that worsen pulmonary vascular resistance (PVR). However, VATS requires one-lung ventilation (OLV) and it tends to cause increase in PVR, leading to right heart failure. In the present case, when the patient was set in a lateral decubitus position and progressive hypoxia was observed during OLV, transesophageal echocardiography demonstrated a dilated right ventricle and a temporally flattened interventricular septum, and the central venous pressure increased to approximately 20 mmHg. Because we anticipated deterioration of right heart function, dobutamine and milrinone were administered and/or respirator settings were changed to decrease PVR for maintaining LVAD performance. Finally, resection of a bulla was completed, and the patient was discharged in stable condition on postoperative day 37. CONCLUSIONS: The anesthetic management of a patient with LVAD during VATS is challenging because the possible hemodynamic changes induced by hypoxia associated with OLV affect LVAD performance and right heart function. In our experience, VATS that requires OLV will be well tolerated in a patient with LVAD with preserved right heart function, and a multidisciplinary approach to maintain right heart function will be needed.

Attachment of a migrated MitraClip to the left ventricular apex: A novel case report.

Herein, we report a novel case of emergency surgical mitral valve replacement for severe mitral valve regurgitation (MR) following MitraClip implantation (Abbott Laboratories, Chicago, IL, USA). Recurrent MR was caused because of the migration of the clip due to the destruction of the mitral valve leaflets with Staphylococcus aureus infective endocarditis. Intra-operative transesophageal echocardiography revealed that the clip was stuck to the left ventricular apex. Although the device could not be removed surgically, surgical repair of the valve enabled the patient to recover without any further complications.

Prevention of Oxygen Desaturation in Morbidly Obese Patients During Electroconvulsive Therapy: A Narrative Review.

In general, preoxygenation is performed using a face mask with oxygen in a supine position, and oxygenation is maintained with manual mask ventilation during electroconvulsive therapy (ECT). However, hypoxic episodes during ECT are not uncommon with this conventional method, especially in morbidly obese patients. The most important property of ventilatory mechanics in patients with obesity is reduced functional residual capacity (FRC). Thus, increasing FRC and oxygen reserves is an important step to improve oxygenation and prevent oxygen desaturation in these individuals. Head-up position, use of apneic oxygenation, noninvasive positive pressure ventilation, and high-flow nasal cannula help increase FRC and oxygen reserves, resulting in improved oxygenation and prolonged safe apnea period. Furthermore, significantly higher incidence of difficult mask ventilation is common in morbidly obese individuals. Supraglottic airway devices establish effective ventilation in patients with difficult airways. Thus, the use of supraglottic airway devices is strongly recommended in these patients. Conversely, because muscle fasciculation induced by depolarizing neuromuscular blocking agents markedly increases oxygen consumption, especially in individuals with obesity, the use of nondepolarizing neuromuscular blocking agents may contribute to better oxygenation in morbidly obese patients during ECT.

Suspected propofol infusion syndrome during normal targeted propofol concentration.

To this day, the pathophysiology and risk factors of propofol infusion syndrome (PRIS) remain unknown. Moreover, there is no widely accepted definition of PRIS, even though it is a potentially fatal condition. While many suspected cases of PRIS have been reported in both pediatric and adult populations, the actual propofol plasma concentration (Cp) has never been clarified. In this clinical report, we described the first suspected PRIS case in which the propofol Cp was measured 25 min after 226 min of propofol infusion (7.2 µg/mL), which was 12 times higher than the predicted value (0.6 µg/mL). In the presented case, we observed gradually progressive uncontrollable hypercapnia and tachycardia, followed by severe lactic acidosis during surgical anesthesia based on the target-controlled infusion of propofol. Levels of liver enzymes were slightly elevated which suggests little or no liver damage though propofol is mainly metabolized by the liver. Meanwhile, renal impairment, a common secondary feature of PRIS, occurred concomitantly when hypercapnia and metabolic acidosis were manifested. In this case, low or delayed propofol clearance might have been a triggering factor causing severe lactic acidosis.

Effect of Right-Lateral Versus Left-Lateral Tilt Position on Compression of the Inferior Vena Cava in Pregnant Women Determined by Magnetic Resonance Imaging.

BACKGROUND: Despite the existing dogma that women undergoing cesarean delivery under spinal anesthesia should be positioned with a 15° left-lateral tilt, the patients were actually positioned in a right-lateral tilt position in several of the original studies. The superiority of right versus left positioning for optimal inferior vena cava volume is unknown. We used magnetic resonance imaging to compare the effects of right-lateral and left-lateral tilt positions on abdominal aortic and inferior vena cava volumes in pregnant women. METHODS: Thirteen women with singleton pregnancies and gestational age 31-39 weeks underwent magnetic resonance imaging while in the supine position, and in the left-lateral (15° and 30°) and right-lateral tilt (15° and 30°) positions, which were maintained by placing a 1.5-m-long piece of polyethylene foam under either side of the body. Abdominal aorta and inferior vena cava volume were measured between the L1-L2 disk and L3-L4 disk levels using magnetic resonance images. RESULTS: Aortic volume did not differ significantly among any of the positions examined. Mean inferior vena cava volume was significantly greater in the 30° left-lateral tilt position than in the 15° right-lateral tilt (10.7 ± 7.5 vs 5.9 ± 5.1 mL; mean difference, 4.8; 95% CI, 1.2-8.5; P = .002) and 30° right-lateral tilt (10.7 ± 7.5 vs 5.9 ± 2.5 mL; mean difference, 4.8; 95% CI, 1.2-8.4; P = .002) positions. Mean inferior vena cava volume in the 15° left-lateral tilt position did not differ significantly from that in the 15° right-lateral tilt (mean difference, 0.4; 95% CI, -3.2 to 4.0; P = 1.000) or 30° right-lateral tilt (mean difference, 0.4; 95% CI, -3.3 to 4.0; P = 1.000) positions. Mean inferior vena cava volume in the supine position only differed significantly from that in the 30° left-lateral tilt position (5.2 ± 3.8 vs 10.7 ± 7.5 mL; mean difference, 5.5; 95% CI, 1.8-9.1; P < .001). The greatest inferior vena cava volume was observed in the 30° left-lateral tilt position in 9 of 13 subjects (70%), and in the 30° right-lateral tilt in 3 subjects (23%). CONCLUSIONS: The 30° left-lateral tilt position most consistently reduced inferior vena cava compression by the gravid uterus compared with the supine position. Mean inferior vena cava volume in pregnant women was not increased at either angle of the right-lateral tilt position compared with the 30° left-lateral tilt position. However, in a subset of patients, the 30° right-lateral tilt position achieved the optimal inferior vena cava volume. Further investigation to understand this variability is warranted.

Perioperative management of patients with cancer pain treated with opioids: a retrospective study.

PURPOSE: We retrospectively studied perioperative management of patients receiving opioid treatment for cancer pain to facilitate establishing a standard policy for our institute. METHODS: Subjects were patients who had been administered strong opioids for cancer pain and had undergone surgery with general anesthesia. We divided the patients into groups C and D. Group C was comprised of patients who had been administered their baseline opioids continuously during the perioperative period, and group D of those who had discontinued baseline opioid use during this period. RESULTS: We identified 70 evaluable patients, 36 in group C and 34 in group D. The intraoperative anesthesia courses were similar, being uneventful, in all cases. With respect to postoperative adverse effects within 24 h after awakening from anesthesia, severe adverse effects (additional administration of more than four analgesics and intense agitation) were significantly more frequent in group D than in group C (12 vs 1, respectively. p = 0.004). Univariate analysis revealed that baseline opioid discontinuation was the only factor associated with severe adverse effects [odds ratio 12.6, 95% confidence interval (1.49-105.8), p = 0.01]. CONCLUSION: Discontinuation of baseline opioid increased adverse effects in the early postoperative period, which were attributed to exacerbation of early postoperative pain.

Changes in heparin dose response slope during cardiac surgery: possible result in inaccuracy in predicting heparin bolus dose requirement to achieve target ACT.

INTRODUCTION: The substantial interpatient variability in heparin requirement has led to the use of a heparin dose response (HDR) technique. The accuracy of Hepcon-based heparin administration in achieving a target activated clotting time (ACT) using an HDR slope remains controversial. METHODS: We prospectively studied 86 adult patients scheduled for cardiac surgery requiring cardiopulmonary bypass. The total dose of calculated heparin required for patient and pump priming was administered simultaneously to achieve a target ACT of 450 s for HDR on the Hepcon HMS system. Blood samples were obtained after the induction of anesthesia, at 3 min after heparin administration and after the initiation of CPB to measure kaolin ACT, HDR slope, whole-blood heparin concentration based on the HDR slope and anti-Xa heparin concentration, antithrombin and complete blood count. RESULTS: The target ACT of 450 s was not achieved in 68.6% of patients. Compared with patients who achieved the target ACT, those who failed to achieve their target ACT had a significantly higher platelet count at baseline. Correlation between the HDR slope and heparin sensitivity was poor. Projected heparin concentration and anti-Xa heparin concentration are not interchangeable based on the Bland-Altman analysis. CONCLUSION: It can be hypothesized that the wide discrepancy in HDR slope versus heparin sensitivity may be explained by an inaccurate prediction of the plasma heparin level and/or the change in HDR of individual patients, depending on in vivo factors such as extravascular sequestration of heparin, decreased intrinsic antithrombin activity level and platelet count and/or activity.

New surgical scoring system to predict postoperative mortality.

PURPOSE: There is still no easy and highly useful method to comprehensively assess both preoperative and intraoperative patient statuses to predict postoperative outcomes. We attempted to develop a new scoring system that would enable a comprehensive assessment of preoperative and intraoperative patient statuses instantly at the end of anesthesia, predicting postoperative mortality. METHODS: The study included 32,555 patients who underwent surgery under general or regional anesthesia from 2008 to 2012. From the anesthesia records, extracted factors, including patient characteristics and American Society of Anesthesiologists physical status classification (ASA-PS), and three intraoperative indexes (the lowest heart rate, lowest mean arterial pressure, and estimated volume of blood loss) are used to calculate the surgical Apgar score (sAs). The sAs and ASA-PS, and surgical Apgar score combined with American Society of Anesthesiologists physical status classification (SASA), which combines the sAs and ASA-PS into a single adjusted scale, were compared and analyzed with postoperative 30-day mortality. RESULTS: Increased severity of the sAs, ASA-PS and SASA was correlated with significantly higher mortality. The risk of death was elevated by 3.65 for every 2-point decrease in the sAs, by 6.4 for every 1-point increase in the ASA-PS, and by 9.56 for every 4-point decrease in the SASA. The ROC curves of the sAs and ASA-PS alone also individually demonstrated high validity (AUC = 0.81 for sAs and 0.79 for ASA-PS, P < 0.001). The SASA was even more valid (AUC = 0.87, P < 0.001). CONCLUSIONS: The sAs and ASA-PS were shown to be extremely useful for predicting 30-day mortality after surgery. An even higher predictive ability was demonstrated by the SASA, which combines these simple and effective scoring systems.

Feasibility of the head-mounted display for ultrasound-guided nerve blocks: a pilot simulator study.

The head-mounted display (HMD) has the potential to improve the quality of ultrasound-guided procedures. The aim of this non-clinical crossover designed study is to evaluate the feasibility of the HMD for ultrasound-guided nerve block. Eight experienced anesthesiologists performed ultrasound-guided peripheral nerve blocks on a training simulator with a standard approach and with an upside-down approach. Each approach was performed with a control conventional method and with an HMD. The ultrasound image and operating field were recorded by video camera. The procedure time and fractional percentage of time with the needle visible on the ultrasound image were determined. The needle insertion times were 10.4 ± 7.2 s with the control method and 6.8 ± 5.3 s with the HMD method for the standard approach (p = 0.03), and 18.1 ± 10.1 with the control method and 11.8 ± 9.5 s with the HMD method for the upside-down approach (p = 0.002). The fractional percentages of time with the needle visible on the ultrasound image were 34.1 ± 20.9 with the control method and 56.5 ± 13.6% with the HMD method for the standard approach (p < 0.001), and 20.1 ± 13.4 with the control method and 38.2 ± 21.2% with the HMD method for the upside-down approach (p = 0.001). In conclusion, this pilot study using a simulation model indicated that the use of an HMD shortened the procedure time and improved the needle visibility on ultrasound.

Comparison of Nellcor™ PM1000N and Masimo Radical-7® for detecting apnea in volunteers.

PURPOSE: Although capnography is considered the gold standard for monitoring of ventilation, it may not work accurately in some situations. We compared the performance of two non-invasive continuous respiratory rate (RR) monitors that are alternatives for the detection of respiratory depression. METHODS: Fifty healthy volunteers ≥20 years old were enrolled in this study. After monitoring of the volunteers was started by the Masimo Radical-7® and Nellcor™ PM1000N, they breathed at the rate of 12 breaths/min for 3 min and then stopped breathing. As soon as the apnea alarm of either monitor went off, breathing was resumed at the same rate. This entire procedure was repeated three times. The data collected every 30 s included the RR, pulse rate (PR) and oxygen saturation (SpO2). The times of alarm on, alarm off and reappearance of RR on the monitor screens were also recorded. RESULTS: The biases of the RR, PR and SpO2 measurements from the two monitors were 0.5, 0.2 and -0.4, respectively. Of 143 procedures that stopped breathing for more than 30 s, 114 and 15 alarms were shown by the Masimo Radical-7® and Nellcor™ PM-1000N monitors, respectively. Most alarms of the Nellcor™ PM1000N followed from SpO2 <90%. Conversely, most alarms of the Masimo Radical-7® were caused by RR <10 breaths/min. Times to alarm on, alarm off and display of RR measured by the Masimo Radical-7® monitor were significantly shorter than the Nellcor™ PM-1000N monitor. CONCLUSIONS: The Masimo Radical-7® monitor provides better detection of apnea in volunteers than the Nellcor™ PM-1000N.

[Evaluation of Near-Eye Type We 21Ae Display for Ultrasound Guided Central Venogii,Gannulation].

BACKGROUND: Recently several types of head- mounted displays are available for use in the medical field. Because head-mounted display can provide the visualized information without moving direction of eye- sight, ultrasound guided central venous cannulation might be performed more quickly and safer. One of the head-mounted type displays, Near-Eye Display (NED; NED prototype product, JCV Kenwood, Japan) was tested in ultrasound guided central venous cannulation. METHODS: Eleven experienced anesthesiologists per- formed central venous cannulation on the training sim- ulator with NED and with control method (without NED). Ultrasound real time image and operating field were recorded by video camera and analyzed to iden- tify procedure time, success rate and incidence of unintentional posterior venous wall penetration. RESULTS: With NED, although time required for cen- tral venous cannulation was similar to the time with standard method (31.3 ± 8.7 sec with control and 30.2 ±7.9 sec with NED, P=0.61), unintentional posterior wall penetration tended to occur less frequently (21% with control and 9% with NED, P=0.17). DISCUSSIONS AND CONCLUSIONS: As NED can help practitioners to have both insertion field and ultra- sound image visible without moving eyesight, NED might be a promising assist device for the ultrasound guided central venous cannulation.

Challenge to pediatric anatomical variation : Can we draw the ideal line on the pediatric I-gel?

OBJECTIVE: I-gel is a noncuff type of laryngeal airway mask. No horizontal line has yet been determined as an ideal position for pediatric sizes because of the variability in length of the oropharyngeal-laryngeal arch in children. We investigated whether there is a correlation between insertion length and patient body weight or height for the pediatric I-gel sizes from 1.5 to 2.5. METHODS: With parental informed consent, we planned to maintain the airway of 130 children aged from 7 months to 13 years by using the I-gel device under general anesthesia. The following two parameters were evaluated: (1) distance between the teeth and the connector wing; (2) insertion length (distance from the distal end of the gastric tube to the teeth). Size selection was determined on the basis of patients' body weight. We identified the relationship between each parameter and height or weight. RESULTS: Average insertion length became gradually longer with increasing height and weight. Spearman's R between insertion length and height or weight was 0.8. There was more correlation with height than with weight in pediatric size 2.5. CONCLUSION: Results suggested that it is possible to draw an ideal line on the I-gel with sizes 1.5 and 2 only.

Electrical impedance tomography-guided prone positioning in a patient with acute cor pulmonale associated with severe acute respiratory distress syndrome.

Electrical impedance tomography (EIT) is a noninvasive technique used to assess regional gas distribution in the lung. We experienced a patient with acute cor pulmonale during high positive-pressure ventilation for the treatment of severe acute respiratory distress syndrome. Prone positioning was beneficial for unloading the right ventricle for treatment of acute cor pulmonale. EIT played a role in detecting lung derecruitment at the patient's bedside. Impedance distribution in ventral, mid-ventral, mid-dorsal, and dorsal layers before and 20 min after the start of prone positioning was 9, 48, 44, and 0 %, and 10, 25, 48, and 16 %, respectively. Lung recruitment monitored by EIT paralleled the improvement of PaO2/FIO2 from 123 to 239 mmHg. Timing of termination of prone positioning and ventilator settings such as lowering positive end-expiration pressure was determined to maintain dorsal recruitment as seen by EIT. The patient was weaned from mechanical ventilation on day 32 and discharged on day 200. EIT assessed the effects of prone positioning with real-time dynamic imaging and guided less injurious mechanical ventilation in a patient with acute cor pulmonale with dorsal lung derecruitment.