Publications by authors named "Isono Shiroh"

79 Publications

Effects of opioids on respiration assessed by a contact-free unconstraint respiratory monitor with load cells under the bed in advanced cancer patients.

J Appl Physiol (1985) 2021 Apr 22. Epub 2021 Apr 22.

Department of Anesthesiology, Chiba University, Japan.

Nocturnal periodic breathing of chronic opioid users has been predominantly documented by use of polysomnography. No previous studies have assessed the opioid effects of respiratory rhythms throughout the day without use of physical restraint. We recently developed a contact-free unconstraint vital sign monitoring system with four load cells placed under the bed legs which allows continuous measurements of respiratory change at the center of gravity on the bed. We aimed to reveal details of the patient's 24-hour respiratory status under a monitoring system and to test the hypothesis that respiratory rhythm abnormalities are opioid dose-dependent and worsens during the night-time. Continuous 48-hour respiratory measurements were successfully performed in 51 advanced cancer patients (12 opioid-free patients and 39 opioid receiving patients). Medians of respiratory variables with minimal body movement artifacts were calculated for each 8-hour split time period. Compared with opioid-free patients, opioid-receiving patients had slower respiratory rate with higher respiratory rate irregularity without changing tidal centroid shift regardless of the time period. Irregular ataxic breathing was only identified in opioid-receiving patients (33%, p=0.023) while incidence rate of periodic breathing did not differ between the groups. Multivariate regression analyses revealed that opioid dose was an independent risk factor for occurrence of irregular breathing (odds ratio 1.81(95%CI: 1.39-2.36), p<0.001), and ataxic breathing (odds ratio 2.08 (95%CI: 1.60-2.71), p<0.001). Females developed the ataxic breathing at lower opioid dose compared to males. We conclude that respiratory rhythm irregularity is a predominant specific feature of opioid-dose dependent respiratory depression particularly in female advanced cancer patients.
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http://dx.doi.org/10.1152/japplphysiol.00904.2020DOI Listing
April 2021

Risk factors including preoperative echocardiographic parameters for post-induction hypotension in general anesthesia.

J Cardiol 2021 Apr 7. Epub 2021 Apr 7.

Department of Anesthesiology, Graduate School of Medicine, Chiba University, Chiba, Japan.

Background: Severe hypotension immediately after induction of general anesthesia (post-induction hypotension) is a common complication and is associated with a poor postoperative outcome. We hypothesized that post-induction hypotension results from cardiac dysfunction which can be assessed by preoperative echocardiography.

Methods: We retrospectively enrolled 200 patients who had undergone elective surgery within 6 months after preoperative transthoracic echocardiography. The incidence of post-induction hypotension identified from anesthesia records was defined as a decrease in mean blood pressure to ≤50 mmHg after injection of induction anesthetics prior to surgery. Logistic regression analysis of patient characteristics and echocardiographic variables was used to identify the independent factors for post-induction hypotension.

Results: Post-induction hypotension was found in 63 of the 200 cases (incidence 32%). Independent risk factors for post-induction hypotension were the presence of a regional wall motion abnormality (RWMA) [odds ratio (OR), 6.65.; 95% confidence interval (CI), 1.76 - 25.10], an elevated E/e' (OR, 1.13; 95% CI, 1.00 - 1.28), female gender (OR, 3.61; 95% CI, 1.37 - 9.56), and the use of an angiotensin II receptor blocker (OR, 3.17; 95% CI, 1.12 - 8.96).

Conclusions: Assessment of RWMA and E/e' with preoperative transthoracic echocardiography might be helpful for stratification of patients at a risk of post-induction hypotension in general anesthesia.
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http://dx.doi.org/10.1016/j.jjcc.2021.03.010DOI Listing
April 2021

Propofol midazolam for sedation during radiofrequency ablation in patients with hepatocellular carcinoma.

JGH Open 2021 Feb 22;5(2):273-279. Epub 2020 Dec 22.

Departmetn of Anesthesiology, Graduate School of Medicine Chiba University Chiba Japan.

Background And Aim: Standardization of the sedation protocol during radiofrequency ablation (RFA) in patients with hepatocellular carcinoma (HCC) is needed. This randomized, single-blind, investigator-initiated trial compared clinical outcomes during and after RFA using propofol and midazolam, respectively, in patients with HCC.

Methods: Few- and small-nodule HCC patients (≤3 nodules and ≤3 cm) were randomly assigned to either propofol or midazolam. Patient satisfaction was assessed using a 100-mm visual analog scale (VAS) (1 mm = not at all satisfied, 100 mm = completely satisfied). Sedation recovery rates 1, 2, 3, and 4 h after RFA were evaluated based on Modified Observer's Assessment of Alertness/Sedation (MOAA/S) scores; full recovery was defined as a MOAA/S score of 5.

Results: Between July 2013 and September 2017, 143 patients with HCC were enrolled, and 135 patients were randomly assigned to the treatment group. Compared with midazolam, propofol exhibited similar median procedural satisfaction (propofol: 73.1 mm, midazolam: 76.9 mm, = 0.574). Recovery rates 1 and 2 h after RFA were higher in the propofol group than in the midazolam group. Meanwhile, recovery rates observed 3 and 4 h after RFA were similar in the two groups. The safety profiles during and after RFA were almost identical in the two groups.

Conclusion: Patient satisfaction was almost identical in patients receiving propofol and midazolam sedation during RFA. Propofol sedation resulted in reduced recovery time compared with midazolam sedation in patients with HCC. The safety profiles of both propofol and midazolam sedation during and after RFA were acceptable.
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http://dx.doi.org/10.1002/jgh3.12483DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7857294PMC
February 2021

Predictor of respiratory disturbances during gastric endoscopic submucosal dissection under deep sedation.

World J Gastrointest Endosc 2020 Oct;12(10):378-387

Department of Frontier Surgery, Chiba University Graduate School of Medicine, Chiba 260-8670, Japan.

Background: Sedation is commonly performed for the endoscopic submucosal dissection (ESD) of early gastric cancer. Severe hypoxemia occasionally occurs due to the respiratory depression during sedation.

Aim: To establish predictive models for respiratory depression during sedation for ESD.

Methods: Thirty-five adult patients undergoing sedation using propofol and pentazocine for gastric ESDs participated in this prospective observational study. Preoperatively, a portable sleep monitor and STOP questionnaires, which are the established screening tools for sleep apnea syndrome, were utilized. Respiration during sedation was assessed by a standard polysomnography technique including the pulse oximeter, nasal pressure sensor, nasal thermistor sensor, and chest and abdominal respiratory motion sensors. The apnea-hypopnea index (AHI) was obtained using a preoperative portable sleep monitor and polysomnography during ESD. A predictive model for the AHI during sedation was developed using either the preoperative AHI or STOP questionnaire score.

Results: All ESDs were completed successfully and without complications. Seventeen patients (49%) had a preoperative AHI greater than 5/h. The intraoperative AHI was significantly greater than the preoperative AHI (12.8 ± 7.6 events/h 9.35 ± 11.0 events/h, = 0.049). Among the potential predictive variables, age, body mass index, STOP questionnaire score, and preoperative AHI were significantly correlated with AHI during sedation. Multiple linear regression analysis determined either STOP questionnaire score or preoperative AHI as independent predictors for intraoperative AHI ≥ 30/h (area under the curve [AUC]: 0.707 and 0.833, respectively) and AHI between 15 and 30/h (AUC: 0.761 and 0.778, respectively).

Conclusion: The cost-effective STOP questionnaire shows performance for predicting abnormal breathing during sedation for ESD that was equivalent to that of preoperative portable sleep monitoring.
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http://dx.doi.org/10.4253/wjge.v12.i10.378DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7579530PMC
October 2020

Qualitative measurement of opioid effects on pain and dyspnea: gender difference in the sensitivity.

JA Clin Rep 2020 Oct 20;6(1):85. Epub 2020 Oct 20.

Department of Anesthesiology, Chiba University Graduate School of Medicine, 1-8-1 Inohana Chuo, Chiba, 260-8670, Japan.

Background: An increasing number of patients come to the operating room in use of opioid analgesics. They have different levels of tolerance to opioid effects which challenge the anesthesiologists in search of safe and effective opioid dosing perioperatively. The tested hypothesis is that simple measures introduced will allow us to measure tolerance qualitatively. Opioid effects on pain (analgesia) and dyspnea sensations (relieving effect) are tested. Patients were allocated to three groups according to pre-operative analgesics: (1) control, without any opioid analgesics, (2) weak opioid, and (3) strong opioid. Pressure pain threshold (PPT) and no-respiratory sensation period (NRSP) were measured at two points: before and 3 min after intravenous fentanyl administration.

Results: A total of 58 (43 controls, 9 weak opioids, and 6 strong opioids) patients were enrolled. PPT and NRSP, after iv 2 μg/kg ideal body weight (IBW) fentanyl, were significantly elevated in the control patients (PPT: 6.2 ± 2.1 N to 9.2 ± 3.9 N, p < 0.0001, NRSP: 17.8 ± 10.8 s to 22.8 ± 18.7 s, p < 0.005, paired t test). However, preoperative opioid use, though with tendency, did not show a significant decrease of the opioid effect. Due to an insufficient number of participants, no conclusion could be drawn. Further analysis of the data from control patients showed a significant difference between the two sexes in sensitivity to PPT and NRSP, as well as fentanyl effect on PPT.

Conclusions: Current data showed a simple method of measuring the opioid effect on two dimensions: pain and respiration. Though not able to show a qualitative measurement of tolerance formation in opioid-users, data from control patients showed females to be more sensitive to pain and dyspnea but is less sensitive to the opioid effect. Further studies are necessary to show whether these gender differences serve as clinical relevance.

Trial Registration: UMIN, UMIN 000011580. Registered 27 August 2013, https://upload.umin.ac.jp/cgi-open-bin/ctr/ctr.cgi?function=brows&action=brows&type=summary&recptno=R000013352&language=J.
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http://dx.doi.org/10.1186/s40981-020-00391-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7575662PMC
October 2020

A report of three cancer patients on opioid analgesia receiving spinal anesthesia: abrupt pain elimination without respiratory depression.

JA Clin Rep 2020 Jul 1;6(1):49. Epub 2020 Jul 1.

Department of Anesthesiology, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chuo Chiba, 260-8670, Japan.

Background: Complete removal of pain with regional anesthesia has been reported to cause fatal respiratory depression in opioid-dependent patients, which leads us to choose general anesthesia. We hereby report three cases of chronically opioid-treated cancer patients operated under spinal anesthesia without respiratory event.

Case Presentation: Case 1: a 32-year-old female treated with high-dose morphine for her cancer pain was planned for cesarean section. Case 2: a 65-year-old female on moderate dose of oxycodone was planned for surgery of her femoral bone fracture. Case 3: a 65-year-old male on low-dose oxycodone was planned for intramedullary nailing for metastatic femoral bone tumor. In all three cases, spinal anesthesia was chosen. Continuous respiratory monitoring revealed no apnea or bradypnea.

Conclusion: Spinal anesthesia was safely performed without respiratory depression in chronic opioid users for cancer pain.
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http://dx.doi.org/10.1186/s40981-020-00355-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7329962PMC
July 2020

A high concentration of sevoflurane induces gasping breaths in mice.

Respir Physiol Neurobiol 2020 08 11;279:103445. Epub 2020 May 11.

Dept of Anesthesiology, Graduate School of Medicine, Chiba University, Japan.

The purpose of this study is to compare changes in breathing patterns elicited by hypoxic stress and/or anesthetic stress in mice. Spontaneously breathing anesthetized mice whose tracheae were intubated with a tracheal cannula were challenged with hypoxic stress and/or sevoflurane-induced anesthetic stress while ventilation was measured with a pneumotachograph. When anesthesia was maintained at a light level with inhalation of 2.3 % sevoflurane (0.7 MAC), exposure to severe hypoxic gas (5% O in N) triggered a breathing pattern characterized by gasping respiration. Inhalation of a high concentration of sevoflurane (6.5 %: 2.0 MAC) under hyperoxia elicited the same gasping. Also, the combination of mild hypoxia (inhalation of 10 % O in N) and moderate sevoflurane anesthesia (3.25 %: 1.0 MAC) consistently elicited the same gasping, while mild hypoxic and moderate anesthetic stress alone did not elicit any gasping. These findings suggest that both hypoxia-induced gasping and sevoflurane-induced gasping could be generated by the same intrinsic mechanism within the brainstem.
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http://dx.doi.org/10.1016/j.resp.2020.103445DOI Listing
August 2020

Effects of postoperative active warming and early exercise on postoperative body temperature distribution: Non-blinded and randomized controlled trial.

Jpn J Nurs Sci 2020 Jul 31;17(3):e12335. Epub 2020 Mar 31.

Frontier Practice Nursing, Graduate School of Nursing, Chiba University, Chiba, Japan.

Aim: We tested a hypothesis that postoperative active warming and/or arm leg stretches reduce the difference between core and skin temperatures (primary variable) improving the peripheral circulation immediately after major abdominal surgery.

Methods: Fifty-one patients undergoing major abdominal surgeries were randomly assigned to receive one of three interventions immediately after surgery; routine care (control group), mild intermittent exercise on the bed (exercise group), and forced-air warming (warming group). Core and skin temperatures and perfusion index were continuously measured from anesthesia induction to 12 h after arrival at the ward.

Results: Core body temperature was maintained over 37°C with a relatively greater gap between core and skin temperatures over 1°C and reduced perfusion index in the early postoperative period in the control group. In the warming group, the reduced skin temperature at arrival at the ward approximated to the core temperature leading to significant reduction of the temperature gap and increasing the perfusion index to the preoperative level. Although less evident, both the temperature gap and peripheral perfusion significantly improved in the exercise group after 6 and 8 h after arrival at the ward, respectively.

Conclusions: Vasoconstriction in response to cessation after anesthesia and surgery serves to maintain core temperature, but impairs peripheral circulation. Active warming and intermittent mild exercise immediately after arrival at the ward reduces the temperature gap and improves peripheral circulation during the early postoperative period. While cost-effectiveness needs to be considered before clinical application of the intervention, the cost-free mild exercise may be a feasible option for improving postoperative patient care.
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http://dx.doi.org/10.1111/jjns.12335DOI Listing
July 2020

Effects of Cardiac Surgery and Salvaged Blood Transfusion on Coagulation Function Assessed by Thromboelastometry.

J Cardiothorac Vasc Anesth 2020 Sep 12;34(9):2375-2382. Epub 2020 Feb 12.

Department of Anesthesiology, Graduate School of Medicine, Chiba University, Chiba, Japan. Electronic address:

Objectives: Coagulation function dynamically changes during cardiac surgery and is normalized after surgery. The authors investigated changes of coagulation function during cardiac surgery and after mimicked salvaged blood transfusion (SBT), and determined background risk factors for coagulation dysfunction by thromboelastmetry including maximum clot firmness of fibrinogen assay (FIBTEM-MCF: primary variable).

Design: Prospective observational study with ex vivo laboratory experiment.

Setting: University hospital.

Participants: Consecutive 65 adult elective cardiac surgery patients being scheduled to use cell salvage technique.

Interventions: Arterial blood sampling (preoperative: after anesthesia induction, and postoperative: after reversal of heparin), and ex vivo dilution of postoperative blood with salvaged blood (7.4%: 2.5 mL + 0.2 mL and 18.5%: 2.2 mL + 0.5 mL).

Measurements And Main Results: Thromboelastometry was performed for the preoperative blood sample, and postoperative blood samples mixed with different amount of the salvaged blood. Preoperative FIBTEM-MCF significantly decreased after cardiac surgery (16.5 [95% confidence interval (15.4-17.6)] mm to 9.5 [8.4-10.6] mm, p < 0.0001). In vitro 7.4% and 18.5% salvaged blood addition dose-dependently reduced FIBTEM-MCF (9.1 [95% confidence interval (8.0-10.1)] mm, 7.9 [6.8-9.0] mm, respectively, p < 0.0001). Preoperative FIBTEM-MCF and changes of FIBTEM-MCF during cardiac surgery were independent risk factors for development of the FIBTEM-MCF 8 mm or less after in vitro salvaged blood addition. Furthermore, residual heparin within salvaged blood was indicated by significant increase of intrinsic assay-clotting time/ heparin assay-clotting time after 18.5% in vitro salvaged blood addition (p < 0.0001).

Conclusions: Salvaged blood transfusion of more than 18.5% whole blood volume may impair coagulation function particularly in patients with lower FIBTEM-MCF before and after cardiac surgery.
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http://dx.doi.org/10.1053/j.jvca.2020.02.009DOI Listing
September 2020

Occurrence of Cortical Arousal at Recovery from Respiratory Disturbances during Deep Propofol Sedation.

Int J Environ Res Public Health 2019 09 18;16(18). Epub 2019 Sep 18.

Department of Frontier Surgery, Graduate School of Medicine, Chiba University, 1-8-1 Inohana-cho, Chuo-ku, Chiba 260-8670, Japan.

A Recent evidences suggest that non-arousal mechanisms can restore and stabilize breathing in sleeping patients with obstructive sleep apnea. This possibility can be examined under deep sedation which increases the cortical arousal threshold. We examined incidences of cortical arousal at termination of apneas and hypopneas in elderly patients receiving propofol sedation which increases the cortical arousal threshold. Ten elderly patients undergoing advanced endoscopic procedures under propofol-sedation were recruited. Standard polysomnographic measurements were performed to assess nature of breathing, consciousness, and occurrence of arousal at recovery from apneas and hypopneas. A total of 245 periodic apneas and hypopneas were identified during propofol-induced sleep state. Cortical arousal only occurred in 55 apneas and hypopneas (22.5%), and apneas and hypopneas without arousal and desaturation were most commonly observed (65.7%) regardless of the types of disordered breathing. Chi-square test indicated that incidence of no cortical arousal was significantly associated with occurrence of no desaturation. Higher dose of propofol was associated with a higher apnea hypopnea index ( = 0.673, = 0.033). In conclusion, even under deep propofol sedation, apneas and hypopneas can be terminated without cortical arousal. However, extensive suppression of the arousal threshold can lead to critical hypoxemia suggesting careful respiratory monitoring.
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http://dx.doi.org/10.3390/ijerph16183482DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6766055PMC
September 2019

Nasopharyngeal Tube Effects on Breathing during Sedation for Dental Procedures: A Randomized Controlled Trial.

Anesthesiology 2019 06;130(6):946-957

From the Department of Anesthesiology, Graduate School of Medicine, Chiba University, Chiba, Japan (Y.K., S.I.) the Department of Anesthesiology, Showa University Koto Toyosu Hospital, Tokyo, Japan (Y.K., T.S.) the Department of Perioperative Medicine, Division of Anesthesiology, Showa University School of Dentistry, Tokyo, Japan (Y.K., S.O., A.K., T.I.) the Department of Dental Anesthesiology and Orofacial Pain, Graduate School of Dentistry, Kyusyu Dental University, Fukuoka, Japan (K.K.) the Department of Oral Health Sciences, Faculty of Dentistry, University of British Columbia, Vancouver, Canada (F.R.A.) the Department of Preventive Medicine and Public Health, Keio University School of Medicine, Tokyo, Japan (Y.S.).

What We Already Know About This Topic: Dental procedures under sedation can cause hypoxic events and even death. However, the mechanism of such hypoxic events is not well understood.

What This Article Tells Us That Is New: Apnea and hypopnea occur frequently during dental procedures under sedation. The majority of the events are not detectable with pulse oximetry. Insertion of a nasal tube with small diameter does not reduce the incidence of apnea/hypopnea.

Background: Intravenous sedation is effective in patients undergoing dental procedures, but fatal hypoxemic events have been documented. It was hypothesized that abnormal breathing events occur frequently and are underdetected by pulse oximetry during sedation for dental procedures (primary hypothesis) and that insertion of a small-diameter nasopharyngeal tube reduces the frequency of the abnormal breathing events (secondary hypothesis).

Methods: In this nonblinded randomized control study, frequency of abnormal breathing episodes per hour (abnormal breathing index) of the patients under sedation for dental procedures was determined and used as a primary outcome to test the hypotheses. Abnormal breathing indexes were measured by a portable sleep monitor. Of the 46 participants, 43 were randomly allocated to the control group (n = 23, no nasopharyngeal tube) and the nasopharyngeal tube group (n = 20).

Results: In the control group, nondesaturated abnormal breathing index was higher than the desaturated abnormal breathing index (35.2 [20.6, 48.0] vs. 7.2 [4.1, 18.5] h, difference: 25.1 [95% CI, 13.8 to 36.4], P < 0.001). The obstructive abnormal breathing index was greater than central abnormal breathing index (P < 0.001), and half of abnormal breathing indexes were followed by irregular breathing. Despite the obstructive nature of abnormal breathing, the nasopharyngeal tube did not significantly reduce the abnormal breathing index (48.0 [33.8, 64.4] h vs. 50.5 [36.4, 63.9] h, difference: -2.0 [95% CI, -15.2 to 11.2], P = 0.846), not supporting the secondary hypothesis.

Conclusions: Patients under sedation for dental procedure frequently encounter obstructive apnea/hypopnea events. The majority of the obstructive apnea/hypopnea events were not detectable by pulse oximetry. The effectiveness of a small-diameter nasopharyngeal tube to mitigate the events is limited.
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http://dx.doi.org/10.1097/ALN.0000000000002661DOI Listing
June 2019

A simple and safe method for tracheal intubation using a supraglottic intubation-aid device in mice.

Respir Physiol Neurobiol 2019 05 18;263:9-13. Epub 2019 Feb 18.

Department of Anesthesiology, Graduate School of Medicine, Chiba University, Japan.

Although mice are a commonly used animal species in experimental medicine, airway management of this species is not easy due to their small size. In order to develop a new method of tracheal intubation in mice, we produced a supraglottic intubation-aid conduit (SIAC) for mice, and tested the efficacy of this device in spontaneously breathing mice anesthetized with sevoflurane inhalation. The success rate of tracheal intubation with the crude prototype of the SIAC was 50% and adverse effects on respiration and some trauma in the upper airway were occasionally observed. After refining the size and shape of the SIAC, the success rate of tracheal intubation with the refined prototype of the SIAC was 100% without any serious adverse effects. This study showed that it is possible to produce a supraglottic airway device to aid tracheal intubation in mice and that the shape and size of the SIAC play a crucial role in successful tracheal intubation in mice.
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http://dx.doi.org/10.1016/j.resp.2019.02.004DOI Listing
May 2019

Contact-free unconstraint respiratory measurements with load cells under the bed in awake healthy volunteers: breath-by-breath comparison with pneumotachography.

J Appl Physiol (1985) 2019 05 14;126(5):1432-1441. Epub 2019 Feb 14.

Department of Preventive Medicine and Public Health, Keio University School of Medicine , Tokyo , Japan.

Rate of respiration is a fundamental vital sign. Accuracy and precision of respiratory rate measurements with contact-free load cell sensors under the bed legs were assessed by breath-by-breath comparison with the pneumotachography technique during two different dynamic breathing tasks in 16 awake human adults resting on the bed. The subject voluntarily increased and decreased the respiratory rate between 4 and 16 breaths/min ( = 8) and 10 and 40 breaths/min ( = 8) at every 2 breaths in 6 different lying postures such as supine, left lateral, right lateral, and 30, 45, and 60° sitting postures. Reciprocal phase changes of the upper and lower load cell signals accorded with the respiratory phases indicating respiratory-related shifts of the centroid along the long axis of the bed. Bland-Altman analyses revealed 0.66 and 1.59 breaths/min standard deviation differences between the techniques (limits of agreement: -1.22 to 1.36 and -2.96 to 3.30) and 0.07 and 0.17 breaths/min fixed bias differences (accuracy) (confidence interval: 0.04 to 0.10 and 0.12 to 0.22) for the mean respiratory rates of 10.5 ± 3.7 and 24.6 ± 8.9 breaths/min, respectively, regardless of the body postures on the bed. Proportional underestimation by this technique was evident for respiratory rates >40 breaths/min. Sample breath increase up to 10 breaths improved the precision from 1.59 to 0.26 breaths/min. Abnormally faster and slower respirations were accurately detected. We conclude that contact-free unconstraint respiratory rate measurements with load cells under the bed legs are accurate and may serve as a new clinical and investigational tool. Four load cells placed under the bed legs successfully captured a centroid shift during respiration in human subjects lying on a bed. Breath-by-breath comparison of the breaths covering a wide respiratory rate range by pneumotachography confirmed reliability of the contact-free unconstraint respiratory rate measurements by small standard deviations and biases regardless of body postures. Abnormally faster and slower respirations were accurately detected. This technique should be an asset as a new clinical and investigational tool.
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http://dx.doi.org/10.1152/japplphysiol.00730.2018DOI Listing
May 2019

Polysomnographic assessment of respiratory disturbance during deep propofol sedation for endoscopic submucosal dissection of gastric tumors.

World J Gastrointest Endosc 2018 Nov;10(11):340-347

Department of Frontier Surgery, Chiba University Graduate School of Medicine, Chiba 260-8670, Japan.

Aim: To investigate that polysomnographic monitoring can accurately evaluate respiratory disturbance incidence during sedation for gastrointestinal endoscopy compare to pulse oximetry alone.

Methods: This prospective observational study included 10 elderly patients with early gastric cancer undergoing endoscopic submucosal dissection (ESD) under propofol sedation. Apart from routine cardiorespiratory monitoring, polysomnography measurements were acquired. The primary hypothesis was tested by comparing the apnea hypopnea index (AHI), defined as the number of apnea and hypopnea instances per hour during sedation, with and without hypoxemia; hypoxemia was defined as the reduction in oxygen saturation by ≥ 3% from baseline.

Results: Polysomnography (PSG) detected 207 respiratory disturbances in the 10 patients. PSG yielded a significantly greater AHI (10.44 ± 5.68/h) compared with pulse oximetry (1.54 ± 1.81/h, < 0.001), thus supporting our hypothesis. Obstructive AHI (9.26 ± 5.44/h) was significantly greater than central AHI (1.19 ± 0.90/h, < 0.001). Compared with pulse oximetry, PSG detected the 25 instances of respiratory disturbances with hypoxemia 107.4 s earlier on average.

Conclusion: Compared with pulse oximetry, PSG can better detect respiratory irregularities and thus provide superior AHI values, leading to avoidance of fatal respiratory complications during ESD under propofol-induced sedation.
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http://dx.doi.org/10.4253/wjge.v10.i11.340DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6247095PMC
November 2018

Displacement of the hyoid bone by muscle paralysis and lung volume increase: the effects of obesity and obstructive sleep apnea.

Sleep 2019 01;42(1)

Department of Anesthesiology, Graduate School of Medicine, Chiba University, Chiba, Japan.

Study Objectives: Animal studies suggest a pivotal role of the hyoid bone in obstructive sleep apnea (OSA). We aimed to explore the role of the hyoid bone in humans by testing the hypotheses that muscle paralysis and lung volume (LV) changes displace the hyoid bone position particularly in people with obesity and/or OSA.

Methods: Fifty patients undergoing general anesthesia participated in this study (20 participants with nonobese, non-OSA; 8 people with nonobese OSA; and 22 people with obese OSA). Three lateral neck radiographs to assess the hyoid position (primary variable) and craniofacial structures were taken during wakefulness, complete muscle paralysis under general anesthesia, and LV increase under general anesthesia. LV was increased by negative extrathoracic pressure application and LV changes were measured with a spirometer. Analysis of covariance was used to identify statistical significance.

Results: Muscle paralysis under general anesthesia significantly displaced the hyoid bone posteriorly (95% CI: 1.7 to 4.6, 1.5 to 5.2, and 1.1 to 4.0 mm in nonobese non-OSA, nonobese OSA, and obese OSA groups, respectively), and this was more prominent in people with central obesity. LV increase significantly displaced the hyoid bone caudally in all groups (95% CI: 0.2 to 0.7, 0.02 to 0.6, and 0.2 to 0.6 mm/0.1 liter LV increase in nonobese non-OSA, nonobese OSA, and obese OSA groups, respectively). Waist-hip ratio was directly associated with the caudal displacement during LV increase.

Conclusions: The hyoid bone plays an important role in the pathophysiology of pharyngeal airway obstruction due to muscle paralysis and LV reduction, particularly in people with obesity.

Clinical Trial: UMIN Clinical Trial Registry, https://upload.umin.ac.jp/cgi-open-bin/ctr/ctr_view.cgi?recptno=cR000022635&language=E, UMIN000019578.
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http://dx.doi.org/10.1093/sleep/zsy198DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6335873PMC
January 2019

Differences of Recovery from Rocuronium-induced Deep Paralysis in Response to Small Doses of Sugammadex between Elderly and Nonelderly Patients.

Anesthesiology 2018 11;129(5):901-911

From the Department of Anesthesiology, Chiba University Hospital, Chiba, Japan (T.M., N.N.-T., Y.K.) the Department of Anesthesiology (S.I., T.I., J.O.) Department of Global Clinical Research (Y.S.), Graduate School of Medicine, Chiba University, Chiba, Japan the Department of Anesthesiology, Kimitsu Chuo Hospital, Kisarazu, Japan (N.M.).

What We Already Know About This Topic: WHAT THIS ARTICLE TELLS US THAT IS NEW: BACKGROUND:: Complete recovery from rocuronium-induced muscle paralysis with sugammadex is reported to be delayed in elderly patients. The authors tested a hypothesis that recovery from deep neuromuscular block with low-dose sugammadex is slower (primary hypothesis) and incidence of recurarization is higher (secondary hypothesis) in elderly patients than in nonelderly patients.

Methods: In anesthetized elderly (n = 20; 76.9 ± 5.0 yr of age) and nonelderly patients (n = 20; 53.7 ± 12.8 yr of age) under deep paralysis with rocuronium, change of train-of-four ratio per minute (primary outcome variable) was measured with an acceleromyograph neuromuscular monitor during spontaneous recovery from rocuronium-induced muscle paralysis (0.6 mg/kg) and after infusion of low-dose sugammadex (50 µg · kg · min). Recurarization was defined as the negative change of train-of-four ratio.

Results: Spontaneous train-of-four ratio recovery rate was significantly slower in the elderly group (median [25th percentile, 75th percentile]: 1.89 [1.22, 2.90] %/min) than in the nonelderly group (3.45 [1.96, 4.25] %/min, P = 0.024). Train-of-four ratio change rate in response to low-dose sugammadex was significantly slower in elderly (0.55 [-0.29, 1.54] %/min) than in the nonelderly group (1.68 [0.73, 3.13] %/min, P = 0.024). Incidence of recurarization was significantly higher in the elderly group than in the nonelderly group (35% vs. 5%, P = 0.044). Multiple linear regression analyses indicate that slower spontaneous train-of-four ratio recovery rate and impaired renal function are two major contributing factors that decrease train-of-four ratio change rate in response to low-dose sugammadex.

Conclusions: Elderly patients are at greater risk for recurarization and residual muscle paralysis when low-dose sugammadex is administered.
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http://dx.doi.org/10.1097/ALN.0000000000002412DOI Listing
November 2018

In Reply.

Anesthesiology 2017 11;127(5):897-898

Graduate School of Medicine, Chiba University, Chiba, Japan (S.I.).

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http://dx.doi.org/10.1097/ALN.0000000000001829DOI Listing
November 2017

Two valves in the pharynx.

Authors:
Shiroh Isono

Eur Respir J 2017 09 20;50(3). Epub 2017 Sep 20.

Dept of Anesthesiology, Graduate School of Medicine, Chiba University, Chiba, Japan

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http://dx.doi.org/10.1183/13993003.01496-2017DOI Listing
September 2017

[Perioperative Management of Obstructive Sleep Apnea Syndrome (OSAS): Introduction of Chiba OSAS Protocol].

Authors:
Shiroh Isono

Masui 2017 01;66(1):18-27

Obstructive sleep apnea syndrome (OSAS) is a common abnormal breathing during sleep among surgical patients and severe perioperative complications may develop in these patients. Anesthesiologists need to know pathophysiology of OSAS, its clinical features, diagnosis and treatments for their proper perioperative airway and hemodynamic management We developed an OSAS management protocol(Chiba OSAS protocol) covering from screening to postoperative airway management of OSAS.
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January 2017

In Reply.

Anesthesiology 2016 12;125(6):1249-1250

Graduate School of Medicine, Chiba University, Chiba, Japan (S.I.).

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http://dx.doi.org/10.1097/ALN.0000000000001374DOI Listing
December 2016

Mask Ventilation during Induction of General Anesthesia: Influences of Obstructive Sleep Apnea.

Anesthesiology 2017 01;126(1):28-38

From the Department of Anesthesiology, Chiba University Hospital, Chiba, Japan (S.S., M.H., M.O., Y.K.); Departments of Anesthesiology (J.O., T.I., S.I.) and Global Clinical Research (Yasunori S.), Graduate School of Medicine, Chiba University, Chiba, Japan; and Department of Anesthesiology, Kaihin General Hospital, Chiba, Japan (Yumi S.).

Background: Depending on upper airway patency during anesthesia induction, tidal volume achieved by mask ventilation may vary. In 80 adult patients undergoing general anesthesia, the authors tested a hypothesis that tidal volume during mask ventilation is smaller in patients with sleep-disordered breathing priorly defined as apnea hypopnea index greater than 5 per hour.

Methods: One-hand mask ventilation with a constant ventilator setting (pressure-controlled ventilation) was started 20 s after injection of rocuronium and maintained for 1 min during anesthesia induction. Mask ventilation efficiency was assessed by the breath number needed to initially exceed 5 ml/kg ideal body weight of expiratory tidal volume (primary outcome) and tidal volumes (secondary outcomes) during initial 15 breaths (UMIN000012494).

Results: Tidal volume progressively increased by more than 70% in 1 min and did not differ between sleep-disordered breathing (n = 42) and non-sleep-disordered breathing (n = 38) patients. In post hoc subgroup analyses, the primary outcome breath number (mean [95% CI], 5.7 [4.1 to 7.3] vs. 1.7 [0.2 to 3.2] breath; P = 0.001) and mean tidal volume (6.5 [4.6 to 8.3] vs. 9.6 [7.7 to 11.4] ml/kg ideal body weight; P = 0.032) were significantly smaller in 20 sleep-disordered breathing patients with higher apnea hypopnea index (median [25th to 75th percentile]: 21.7 [17.6 to 31] per hour) than in 20 non-sleep disordered breathing subjects with lower apnea hypopnea index (1.0 [0.3 to 1.5] per hour). Obesity and occurrence of expiratory flow limitation during one-hand mask ventilation independently explained the reduction of efficiency of mask ventilation, while the use of two hands effectively normalized inefficient mask ventilation during one-hand mask ventilation.

Conclusions: One-hand mask ventilation is difficult in patients with obesity and severe sleep-disordered breathing particularly when expiratory flow limitation occurs during mask ventilation.
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http://dx.doi.org/10.1097/ALN.0000000000001407DOI Listing
January 2017

Physiological and Biochemical Responses to Continuous Saline Irrigation Inside the Abdominal Cavity in Anesthetized Pigs.

J Laparoendosc Adv Surg Tech A 2016 Aug 19;26(8):600-5. Epub 2016 May 19.

4 Department of Anesthesiology, Graduate School of Medicine, Chiba University , Chiba, Japan .

Background: Water-filled laparoendoscopic surgery (WaFLES) has been proposed as a novel surgical system achieving a wide surgical field in the intra- and extraperitoneal space with continuous irrigation of isotonic fluid into the field. Despite its technical feasibility and advantages, the safety of the technique, particularly with respect to physiological functions, has not been evaluated.

Methods: Various types of minor abdominal surgeries were performed under general anesthesia in nine adult pigs either by conventional laparoscopy (n = 3) or WaFLES (n = 6). In addition to esophageal temperature and body weight, cardiorespiratory variables such as blood pressure, heart rate, and arterial blood gas parameters were compared before and after the surgeries. Blood samples were obtained for assessing changes in biochemical parameters before and after the surgeries.

Results: Three to seven hours of various surgeries were completed without critical cardiorespiratory events in all animals. Oxygenation and ventilation were maintained regardless of the techniques used for the surgeries. A minor increase of body weight (2.5% of initial body weight), metabolic acidosis, hyperkalemia, and impaired hepatic function were observed after WaFLES surgeries.

Conclusions: The preliminary study indicated no serious immediate adverse effects of the WaFLES technique.
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http://dx.doi.org/10.1089/lap.2015.0463DOI Listing
August 2016

[Patient's Risk Factors for Perioperative Aspiration Pneumonia].

Masui 2016 Jan;65(1):23-8

This article reviews patient's own risk factors for perioperative aspiration pneumonia. Maintaining the function of the lower esophageal sphincter (LES), the airway protective reflex, and the oral hygiene are the most important to prevent the pneumonia. The LES is adversely affected by excessive stomach distention, some medication given in perioperative periods, and habitual smoking, as well as pathological status such as esophageal hiatus hernia and achalasia. Postapoplectic patients may have insufficient airway protective reflex including swallowing and laryngeal reflex. It is emphasized that the perioperative oral care is increasing in its importance for the prevention of aspiration pneumonia.
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January 2016

Do You Believe What You See or What You Hear? Ultrasound versus Stethoscope for Perioperative Clinicians.

Anesthesiology 2016 May;124(5):989-91

From the Department of Anesthesiology, Graduate School of Medicine, Chiba University, Chiba, Japan (S.I.); Departments of Anesthesiology, Surgery, and Biomedical Informatics (W.S.S.); and Department of Anesthesiology (Y.J.), Vanderbilt University Medical Center, Nashville, Tennessee.

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http://dx.doi.org/10.1097/ALN.0000000000001074DOI Listing
May 2016

[Is Extubation Art or Science?].

Authors:
Shiroh Isono

Masui 2015 Oct;64(10):1009

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October 2015

New approach to relieving pain and distress during high-dose-rate intracavitary irradiation for cervical cancer.

Brachytherapy 2015 Sep-Oct;14(5):642-7. Epub 2015 May 27.

Department of Radiology and Radiation Oncology, Graduate School of Medicine, Chiba University, Chiba, Japan; Department of Radiology, Chiba University Hospital, Chiba, Japan.

Background And Purpose: To relieve the pain and distress experienced by women who undergo high-dose-rate intracavitary radiotherapy (HDR-ICRT) for cervical cancer and to improve the current status of gynecologic brachytherapy in Japan, a new intravenous anesthetic protocol involving the administration of a combination of propofol and ketamine was developed. The primary aim of this study is to investigate the efficacy and safety of this new anesthetic protocol during HDR-ICRT for cervical cancer.

Methods And Materials: All the patients who were diagnosed with cervical cancer between December 2008 and February 2011, treated with three-channel brachytherapy and subjected to the new sedation protocol, were evaluated. A visual analog scale (VAS) was used to assess the pain during brachytherapy, and we collected VAS score at the next HDR-ICRT. Toxicities were graded using the Common Toxicity Criteria, version 3.

Results: A total of 178 sessions of HDR-ICRT were delivered to 57 patients. The patients' median VAS pain score was 0 (range, 0-10). The most frequent side effect was Grade 1-2 nausea, which occurred in 33 sessions (34%). However, 13 of 14 patients received concurrent cisplatin chemotherapy. None of the patients experienced Grade 3 or 4 adverse events.

Conclusions: We have demonstrated that our new intravenous anesthetic protocol produces appropriate effects and can be performed by radiation oncologists who were required to finish training in basic life support and the cooperative system of emergency according to in-house guideline.
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http://dx.doi.org/10.1016/j.brachy.2015.04.009DOI Listing
May 2016

[Publication of an original work: for self accomplishment as well as for advancement of medicine].

Authors:
Shiroh Isono

Masui 2015 Jan;64(1):49-56

Medical researchers are expected to give back their study results to society (the patient). In this context conference presentation and publication in a scientific journal are the final stages for the purpose. Therefore, the researchers should have knowledge and skill on how to present and write the results logically, readably and attractively as a scientific original manuscript Scientific misconduct such as fabrication and plagiarism blocks advance of the field and deserve social and criminal sanction. Reviewers of the manuscript place a high value of novelty of the research and its clinical and scientific impact in addition to accuracy and reproducibility of the methodology of the study. They provide constructive suggestions for improving it as experts of the field. The authors should read their comments carefully and communicate with them effectively. Young anesthesiologists are encouraged to experience a sense of achievement of publication of their original work.
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January 2015

Submental negative pressure application decreases collapsibility of the passive pharyngeal airway in nonobese women.

J Appl Physiol (1985) 2015 Apr 22;118(7):912-20. Epub 2015 Jan 22.

Department of Anesthesiology, Chiba University Hospital, Chiba, Japan; and.

The pharyngeal airway is surrounded by soft tissues that are also enclosed by bony structures such as the mandible, maxilla, and cervical spine. The passive pharyngeal airway is therefore structurally analogous to a collapsible tube within a rigid box. Cross-sectional area of the tube is determined by transmural pressure, the pressure difference between intraluminal and extraluminal pressures. Due to a lack of knowledge on the influence of extraluminal soft tissue pressure on the human pharyngeal airway patency, we hypothesized that application of negative external pressure to the submental region decreases collapsibility of the passive pharynx, and that obese individuals have less response to the intervention than nonobese individuals. Static mechanical properties of the passive pharynx were compared before and during application of submental negative pressure in 10 obese and 10 nonobese adult women under general anesthesia and paralysis. Negative pressure was applied through use of a silicone collar covering the entire submental region and a vacuum pump. In nonobese subjects, application of submental negative pressure (-25 and -50 cmH2O) significantly decreased closing pressures at the retropalatal airway by 2.3 ± 3.2 cmH2O and 2.0 ± 3.0 cmH2O, respectively, and at the retroglossal airway by 2.9 ± 2.7 cmH2O and 3.7 ± 2.6 cmH2O, respectively, and the intervention stiffened the retroglossal pharyngeal airway wall. No significant mechanical changes were observed during application of submental negative pressure in obese subjects. Conclusively, application of submental negative pressure was found to decreases collapsibility of the passive pharyngeal airway in nonobese Japanese women.
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http://dx.doi.org/10.1152/japplphysiol.00158.2014DOI Listing
April 2015

Is the light green for your airway management?

Authors:
Shiroh Isono

J Anesth 2014 Aug 4;28(4):479-81. Epub 2014 Jul 4.

Department of Anesthesiology, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba, 263-8670, Japan,

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http://dx.doi.org/10.1007/s00540-014-1851-5DOI Listing
August 2014