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Toshiaki Nishikawa - One of the best experts on this subject based on the ideXlab platform.
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propofol requirement for insertion of cuffed Oropharyngeal Airway versus laryngeal mask Airway with and without fentanyl a dose finding study
BJA: British Journal of Anaesthesia, 2003Co-Authors: Makoto Tanaka, Toshiaki NishikawaAbstract:Background The cuffed Oropharyngeal Airway (COPA) is a modified Guedel-type oral Airway with a cuff at its distal end. The objectives of this prospective, randomized study were to compare the COPA and the laryngeal mask Airway (LMA † †LMA ® is the property of Intavent Limited.) in terms of propofol requirement with and without fentanyl pretreatment for smooth insertions. Methods Seventy-five patients undergoing general anaesthesia were randomly assigned to either a COPA ( n =38) or LMA ( n =37) group for Airway management, and each group was further randomized to a saline-propofol or fentanyl-propofol group for anaesthesia induction. The saline-propofol group received i.v. saline and the fentanyl-propofol group received i.v. fentanyl 1 μg kg −1 followed 30 s later by i.v. propofol. Insertion of the device was attempted 90 s after propofol administration without the use of neuromuscular blocking agents or other adjuvants, and the responses of ‘movement' or ‘no movement' were judged by three observers blinded to the drug dose. Each dose of propofol at which insertion was attempted was predetermined by modification of Dixon's up-and-down method with 0.5 mg kg −1 as the step size, and 2 mg kg −1 as an initial dose. Results Without fentanyl pretreatment, propofol requirement [mean (sd), 95% CI] for COPA placement [2.17 (0.38), 1.77–2.56 mg kg −1 ] was significantly less than for LMA insertion [3.42 (0.26), 3.15–3.69 mg kg −1 , P −1 , respectively], but were less than for the placebo group with both devices ( P Conclusions Insertion of the COPA can be accomplished with a smaller bolus dose of propofol compared with the LMA, but propofol requirements are similar with both devices after a small dose of fentanyl.
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minimum alveolar sevoflurane concentrations required for insertion of the cuffed Oropharyngeal Airway and the laryngeal mask Airway a comparative study
Anaesthesia, 1999Co-Authors: Makoto Tanaka, S. Watanabe, Toshiaki NishikawaAbstract:Both the cuffed Oropharyngeal Airway and the laryngeal mask Airway share a similar property of being less stimulating to the upper Airway than the tracheal tube. This study was conducted to compare sevoflurane concentrations required for insertion of the cuffed Oropharyngeal Airway and the laryngeal mask Airway in elderly and young adult patients. Forty-one elderly (65-90 years) and 34 young adult (18-5() years) patients, scheduled for elective surgery during spontaneous breathing anaesthesia were randomly assigned to either the cuffed Oropharyngeal Airway or the laryngeal mask Airway group. After a predetermined end-tidal concentration of sevoflurane had been established and maintained for at least 20 min, insertion of the device was attempted without neuromuscular relaxants or other adjuvants. Each concentration at which insertion of the device was attempted was predetermined by modification of Dixon's up-and-down method with 0.5% as the step size. Sevoflurane MAC COPA [mean 1.17 (SD 0.38)%, 0.77-1.56% (95% CI)] was significantly less than MAC LMA [2.00 (0.52)%, 1.45-2.55%, p<0.05] for elderly patients. Similarly, sevoflurane MAC COPA [1.33 (0.38)%, 0.94-1.73%] was significantly less than MAC LMA [2.00 (0.42)%, 1.56-2.44%, p<0.05] for young adult patients. There were no significant differences in either MAC COPA or MAC LMA between the elderly and the young adult patients. We conclude that the insertion of the cuffed Oropharyngeal Airway can be accomplished at a lower sevoflurane concentration, and hence, is less stimulating to the upper Airway than that of the laryngeal mask Airway.
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Minimum alveolar sevoflurane concentrations required for insertion of the cuffed Oropharyngeal Airway and the laryngeal mask Airway: a comparative study.
Anaesthesia, 1999Co-Authors: Makoto Tanaka, S. Watanabe, Toshiaki NishikawaAbstract:Both the cuffed Oropharyngeal Airway and the laryngeal mask Airway share a similar property of being less stimulating to the upper Airway than the tracheal tube. This study was conducted to compare sevoflurane concentrations required for insertion of the cuffed Oropharyngeal Airway and the laryngeal mask Airway in elderly and young adult patients. Forty-one elderly (65-90 years) and 34 young adult (18-5() years) patients, scheduled for elective surgery during spontaneous breathing anaesthesia were randomly assigned to either the cuffed Oropharyngeal Airway or the laryngeal mask Airway group. After a predetermined end-tidal concentration of sevoflurane had been established and maintained for at least 20 min, insertion of the device was attempted without neuromuscular relaxants or other adjuvants. Each concentration at which insertion of the device was attempted was predetermined by modification of Dixon's up-and-down method with 0.5% as the step size. Sevoflurane MAC COPA [mean 1.17 (SD 0.38)%, 0.77-1.56% (95% CI)] was significantly less than MAC LMA [2.00 (0.52)%, 1.45-2.55%, p
Giorgio Torri - One of the best experts on this subject based on the ideXlab platform.
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Arterial to end-tidal carbon dioxide tension difference in anaesthetized adults mechanically ventilated via a laryngeal mask or a cuffed Oropharyngeal Airway.
European journal of anaesthesiology, 1999Co-Authors: Andrea Casati, Guido Fanelli, Gianluca Cappelleri, Andrea Albertin, D. Anelati, L. Magistris, Giorgio TorriAbstract:To evaluate arterial (PaCO2), end-tidal (PETCO2) and carbon dioxide tension difference during mechanical ventilation with extratracheal Airways, 60 patients ASA physical status I-II, receiving general anaesthesia for minor extra-abdominal procedures were randomly allocated to receive either a cuffed Oropharyngeal Airway (group COPA, n = 30) or a laryngeal mask (group LMA, n = 30). The lungs were mechanically ventilated by IPPV using a 60% nitrous oxide and 1-1.5% isoflurane in oxygen mixture (VT = 8 mL kg-1; RR = 12 b min-1; l/E = 1/2). After PETCO2 had been stable for at least 10 min after Airway placement, haemodynamic variables and PETCO2 were recorded and an arterial blood sample was obtained for measurement of PaCO2. No differences in anthropometric parameters, smoking habit, haemodynamic variables and incidence of untoward events were observed between the two groups. Airway manipulation, to maintain adequate ventilation, was required in only nine patients in the cuffed Oropharyngeal Airway group (30%) (P < 0.0005); however, in no case was it necessary to remove the designated extratracheal Airway due to unsuccessful mechanical ventilation. The mean difference between arterial and end-tidal carbon dioxide partial pressure was 0.4 +/- 0.3 KPa in the laryngeal mask group (95% confidence intervals: 0.3-0.5 KPa) and 0.3 +/- 0.26 KPa in the cuffed Oropharyngeal Airway group (95% confidence intervals: 0.24-0.4 KPa) (P = NS). We conclude that in healthy adults who are mechanically ventilated via the cuffed Oropharyngeal Airway, the end-tidal carbon dioxide determination is as accurate an indicator of PaCO2 as that measured via the laryngeal mask, allowing capnometry to be reliably used to evaluate the adequacy of ventilation.
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The target plasma concentration of propofol required to place laryngeal mask versus cuffed Oropharyngeal Airway
Anesthesia and analgesia, 1999Co-Authors: Andrea Casati, Guido Fanelli, Elisabetta Casaletti, Valeria Cedrati, Fabrizio Veglia, Giorgio TorriAbstract:To determine the target plasma concentration of propofol required to place either a laryngeal mask Airway (LMA) or a cuffed Oropharyngeal Airway (COPA), we started a continuous target-controlled infusion of propofol in 60 ASA physical status I or II unpremedicated patients scheduled for minor orthopedic surgery with peripheral nerve block. The target plasma concentration of propofol was initially set at 2 microg/mL. When the effect-site calculated concentration of propofol was equal to the plasma concentration according to the computer simulation, the target plasma concentration was increased by 0.5-microg/mL steps until successful placement of either the LMA (n = 30) or the COPA (n = 30). The mean target plasma concentration of propofol required to place a LMA was 4.3 +/- 0.8 microg/mL compared with 3.2 +/- 0.6 microg/mL to place a COPA (P Implications We evaluated the use of target-controlled infusion of propofol to place extratracheal Airways in this prospective, randomized study and demonstrated that the target plasma concentration of propofol required to successfully place a laryngeal mask in >95% of healthy, unpremedicated patients is 6 microg/mL, compared with 4 microg/mL to place a cuffed Oropharyngeal Airway.
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The pressor response after laryngeal mask or cuffed Oropharyngeal Airway insertion.
Acta anaesthesiologica Scandinavica, 1999Co-Authors: Andrea Casati, Guido Fanelli, Gianluca Cappelleri, Andrea Albertin, L. Magistris, P Beccaria, Giorgio TorriAbstract:Background: Since the cuffed Oropharyngeal Airway (COPA) has been suggested to cause less pharyngeal trauma than the laryngeal mask Airway (LMA), we conducted a prospective, randomised study to compare haemodynamic changes after placing either the COPA or LMA in healthy anaesthetised adults. Methods: After standard midazolam premedication (0.05 mg kg−1 IV), general anaesthesia (IV propofol 2 mg kg−1) was induced in 60 ASA physical status I–II, 18–65-yr-old patients, who were randomly allocated to receive COPA (n=30) or LMA (n=30) placement and then mechanically ventilated using a 60% nitrous oxide and 1% isoflurane in oxygen mixture (TV=8 ml kg−1, RR=12 b.p.m., I/E=1/2). Haemodynamic variables were recorded 20 min after the midazolam premedication (baseline), and then every 1 min until 10 min after general anaesthesia induction. Results: Nine patients of group COPA (30%) required chin lift, jaw thrust or head tilt to maintain adequate ventilation, while no problems were observed in the LMA group (P
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physiological dead space tidal volume ratio during face mask laryngeal mask and cuffed Oropharyngeal Airway spontaneous ventilation
Journal of Clinical Anesthesia, 1998Co-Authors: Andrea Casati, Guido Fanelli, Giorgio TorriAbstract:Abstract Objective: To compare the physiological dead space/tidal volume ratio and arterial to end-tidal carbon dioxide tension (ETCO 2 ) difference during spontaneous ventilation through a face mask, a laryngeal mask (LMA), or a cuffed Oropharyngeal Airway. Design: Prospective, randomized, cross-over study. Setting: Inpatient anesthesia at a university department of orthopedic surgery. Patients: 20 ASA physical status I and II patients, without respiratory disease, who underwent ankle and foot surgery. Interventions: After a peripheral nerve block was performed, propofol anesthesia was induced and then maintained with a continuous intravenous (IV) infusion (4 to 6 mg/kg/h). A face mask, a cuffed Oropharyngeal Airway, or an LMA were placed in each patient in a random sequence. After 15 minutes of spontaneous breathing through each of the Airways, ventilatory variables, as well as arterial, end-tidal, and mixed expired CO 2 partial pressure, were measured, and physiological dead space/tidal volume ratio was calculated. Measurements and Main Results: Expired minute volume and respiratory rate (RR) were lower with LMA (5.6 ± 1.2 L/min and 18 ± 3 breaths/min) and the cuffed Oropharyngeal Airway (5.7 ± 1 L/minand 18 ± 3 breaths/min) than the face mask (7.1 ± 0.9 L/min and 21 ± 3 breaths/min) (p = 0.0002 and p=0.013, respectively). Physiological dead space/tidal volume ratio and arterial to end tidal CO 2 tension difference were similar with the cuffed Oropharyngeal Airway (3 ± 0.4 mmHg and 4.4 ± 1.4 mmHg) and LMA (3 ± 0.6 mmHg and 3.7 ± 1 mmHg) and lower than with the face mask (4 ± 0.5 mmHg and 6.7 ± 2 mmHg) (p = 0.0001 and p=0.001, respectively). Conclusion: Because of the increased dead space/tidal volume ratio, breathing through a face mask required higher RR and expired minute volume than either the cuffed Oropharyngeal Airway or LMA, which, in contrast, showed similar effects on the quality of ventilation in spontaneously breathing anesthetized patients.
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Physiological dead space/tidal volume ratio during face mask, laryngeal mask, and cuffed Oropharyngeal Airway spontaneous ventilation
Journal of clinical anesthesia, 1998Co-Authors: Andrea Casati, Guido Fanelli, Giorgio TorriAbstract:Abstract Objective: To compare the physiological dead space/tidal volume ratio and arterial to end-tidal carbon dioxide tension (ETCO 2 ) difference during spontaneous ventilation through a face mask, a laryngeal mask (LMA), or a cuffed Oropharyngeal Airway. Design: Prospective, randomized, cross-over study. Setting: Inpatient anesthesia at a university department of orthopedic surgery. Patients: 20 ASA physical status I and II patients, without respiratory disease, who underwent ankle and foot surgery. Interventions: After a peripheral nerve block was performed, propofol anesthesia was induced and then maintained with a continuous intravenous (IV) infusion (4 to 6 mg/kg/h). A face mask, a cuffed Oropharyngeal Airway, or an LMA were placed in each patient in a random sequence. After 15 minutes of spontaneous breathing through each of the Airways, ventilatory variables, as well as arterial, end-tidal, and mixed expired CO 2 partial pressure, were measured, and physiological dead space/tidal volume ratio was calculated. Measurements and Main Results: Expired minute volume and respiratory rate (RR) were lower with LMA (5.6 ± 1.2 L/min and 18 ± 3 breaths/min) and the cuffed Oropharyngeal Airway (5.7 ± 1 L/minand 18 ± 3 breaths/min) than the face mask (7.1 ± 0.9 L/min and 21 ± 3 breaths/min) (p = 0.0002 and p=0.013, respectively). Physiological dead space/tidal volume ratio and arterial to end tidal CO 2 tension difference were similar with the cuffed Oropharyngeal Airway (3 ± 0.4 mmHg and 4.4 ± 1.4 mmHg) and LMA (3 ± 0.6 mmHg and 3.7 ± 1 mmHg) and lower than with the face mask (4 ± 0.5 mmHg and 6.7 ± 2 mmHg) (p = 0.0001 and p=0.001, respectively). Conclusion: Because of the increased dead space/tidal volume ratio, breathing through a face mask required higher RR and expired minute volume than either the cuffed Oropharyngeal Airway or LMA, which, in contrast, showed similar effects on the quality of ventilation in spontaneously breathing anesthetized patients.
Shigeho Morita - One of the best experts on this subject based on the ideXlab platform.
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Insertion of the cuffed Oropharyngeal Airway (COPA) with propofol or sevoflurane in adults.
Journal of clinical anesthesia, 1999Co-Authors: Takahisa Goto, Yoshinori Nakata, Shoichi Uezono, Yoshinari Niimi, Masanori Uchiyama, Shigeho MoritaAbstract:Abstract Study Objectives: To compare the respiratory depressant effects of propofol and sevoflurane used to facilitate the placement of the cuffed Oropharyngeal Airway (COPA), and to evaluate the effectiveness of the COPA in supporting positive pressure ventilation during anesthetic-induced apnea. Design: Randomized, single-blinded study. Setting: University hospital. Patients: 60 ASA physical status I and II adult patients scheduled for elective surgery with general anesthesia. Interventions: Patients were induced either with spontaneous inhalation of 5% sevoflurane or with propofol 2.0 mg/kg intravenously (IV) followed by a continuous infusion of 170 μg kg −1 min −1 . If the propofol patient had a tight jaw in 90 seconds, additional propofol (0.5 mg/kg) was administered and the infusion rate was increased to 200 μg kg −1 min −1 . The COPA was placed as soon as the jaw was sufficiently relaxed to allow its insertion into the mouth. Measurements and Main Results: The median (range) times to the COPA placement were 90 seconds (30 to 150 sec) and 120 seconds (60 to 210 sec) with propofol and sevoflurane, respectively ( p = 0.07, Mann-Whitney U -test). Unacceptable responses to the placement (3 or more coughs, vigorous or persistent [>30 sec] movements) occurred in 23% and 17% of those who received propofol and sevoflurane, respectively, ( p = 0.35, Chi-square test). All these responses were easily suppressed by additional doses of the assigned induction drug. After placement of the COPA, 53% (16/30) of the propofol patients had apnea lasting at least 30 seconds. Notably, the positive Airway pressure at which a leak occurred in the mouth (pharyngeal leak pressure) was lower during this propofol-induced apnea than after the return of spontaneous breathing [9 (5 to 20) cmH 2 O vs. 15 (5 to 20) cmH 2 O, p 2 O. Conclusions: Propofol and sevoflurane are equally effective in facilitating the placement of the COPA. However, propofol often induces apnea, which is complicated by a less effective seal of the Airway by the COPA against positive pressures. Because sevoflurane induction allows spontaneous respiration to continue and provides an adequate pharyngeal seal immediately following the placement of the COPA, it may be advantageous when apnea is not desired.
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The Cuffed Oropharyngeal Airway, a Novel Adjunct to the Management of Difficult Airways
Anesthesiology, 1998Co-Authors: Shoichi Uezono, Yoshinori Nakata, Takahisa Goto, Fumito Ichinose, Yosinari Niimi, Shigeho MoritaAbstract:A cuffed Oropharyngeal Airway (COPA) is a new Airway device, which is fundamentally a regular oropharyngheal Airway with a large cuff attached around the distal end. The cuff separates the tongue from the posterior pharyngeal wall to create a patent Airway. Proximally it has a standard 15-mm adapter connectable to a breathing circuit. Like a laryngeal mask Airway (LMA), it is intended primarily for use in spontaneously breathing patients who are not at risk of aspiration of gastric contents. Consistent with the preliminary reports, by others, 1,2 our initial experiences with COPA in more than 100 patients have been favorable. We report here our experience of using this new device in two patients requiring general anesthesia for whom fiberoptic intubation was performed with the COPA in place.
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The Placement of the Cuffed Oropharyngeal Airway with Sevoflurane in Adults
Anesthesia & Analgesia, 1998Co-Authors: Yoshinori Nakata, Takahisa Goto, Hayato Saito, Fumito Ichinose, Shoichi Uezono, Shigeho MoritaAbstract:We sought to determine the anesthetic duration of sevoflurane required to achieve good conditions for placement of a cuffed Oropharyngeal Airway (COPA) or a laryngeal mask Airway (LMA).Forty adult ASA physical status I or II patients presenting for elective surgery received single-breath vital capac
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The Placement of the Cuffed Oropharyngeal Airway with Sevoflurane in Adults: A Comparison with the Laryngeal Mask Airway
Anesthesia and analgesia, 1998Co-Authors: Yoshinori Nakata, Takahisa Goto, Hayato Saito, Fumito Ichinose, Shoichi Uezono, Shigeho MoritaAbstract:UNLABELLED We sought to determine the anesthetic duration of sevoflurane required to achieve good conditions for placement of a cuffed Oropharyngeal Airway (COPA) or a laryngeal mask Airway (LMA). Forty adult ASA physical status I or II patients presenting for elective surgery received single-breath vital capacity inhaled induction with 5% sevoflurane via face mask; thereafter, ventilation was manually assisted. The patients were randomized to receive either a COPA or LMA placement. The time of anesthetic exposure was varied for consecutive patients using the staircase method. The mean (95% confidence interval) anesthetic time required for acceptable COPA placement (100 [55-145] s) was significantly shorter than that for LMA (160 [101-219] s). The 50% and 95% effective doses (from logistic analyses) for acceptable conditions associated with COPA or LMA placement were 90 s and 145 s or 164 s and 261 s, respectively. These findings suggest that COPA insertion is less stimulating than the LMA. IMPLICATIONS The cuffed Oropharyngeal Airway is a new Airway device that is similar to a laryngeal mask Airway in many ways. However, it requires shorter anesthetic duration for successful placement, which suggests that it can be placed with less stimulation. It may be an alternative to a laryngeal mask Airway.
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Relationship between end-tidal and arterial carbon dioxide partial pressure using a cuffed Oropharyngeal Airway and a tracheal tube
British journal of anaesthesia, 1998Co-Authors: Yoshinori Nakata, Takahisa Goto, Shoichi Uezono, F Sasaki, Shigeho MoritaAbstract:We have compared the differences between end-tidal PE'CO2 and arterial PaCO2 carbon dioxide partial pressures during general anaesthesia using either a cuffed Oropharyngeal Airway (COPA) or a tracheal tube (TT) in spontaneously breathing adult patients. After induction of anaesthesia, a COPA was inserted in 20 patients who were allowed to breathe spontaneously. When steady state was reached, PE'CO2 and PaCO2 were recorded. The COPA was removed, the trachea intubated with a TT and spontaneous ventilation allowed to resume. After a stable PE'CO2 was reestablished, PaCO2 was measured again and PE'CO2 recorded. Mean difference between PaCO2 and PE'CO2 with the COPA was 0.72 (SD 0.45) kPa and with the TT 0.64 (0.40) kPa (ns; paired t test). Our results suggest that Pe'CO2 is a clinically acceptable indicator of PaCO2 in adults breathing spontaneously via a COPA.
Ronald M Harper - One of the best experts on this subject based on the ideXlab platform.
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epiglottis cross sectional area and Oropharyngeal Airway length in male and female obstructive sleep apnea patients
Nature and Science of Sleep, 2016Co-Authors: Melinda A, Rajesh Kumar, Paul M Macey, Frisca L Yango, Ronald M HarperAbstract:Obstructive sleep apnea (OSA) is a male-predominant condition, characterized by repeated upper-Airway collapse with continued diaphragmatic efforts during sleep, and is accompanied by severe physiological consequences. Multiple morphological aspects, including epiglottis cross-sectional area (CSA) and Oropharyngeal Airway length (OPAL), can contribute to Airway collapsibility in the condition. This study focused on the effects of OSA severity, sex, and race on OPA dimensions.Two high-resolution T1-weighted image series were collected from 40 mild-to-severe OSA subjects (age 46.9±9 years, body mass index 30.4±5.4 kg/m2, Apnea-Hypopnea Index score 32.8±22.5, 28 males) and 54 control subjects (47±9 years, 24.7±3.8 kg/m2, 32 males) using a 3 T magnetic resonance-imaging scanner. Caucasian, Asian, African-American, and "other" subjects constituted the study pool. Both image series were realigned and averaged, and reoriented to a common space. CSA and OPAL were measured, normalized for subject height, and compared between sexes and disease-severity levels in OSA and control subjects.Significantly reduced epiglottis CSA appeared only in severe OSA vs controls (P=0.009). OPAL increased significantly with OSA severity vs controls (mild, P=0.027; moderate, P<0.001; severe, P<0.001). OSA males showed increased CSA and greater OPAL than OSA females, which may underlie the increased proportion of affected males with higher apnea-hypopnea index scores. However, no significant differences appeared between CSA and OPAL measures for male and female controls, suggesting that Airway morphology may not be the sole contributor for Airway collapse. No ethnic or racial differences appeared for CSA or OPAL measures.Sex-based reductions in epiglottis CSA and increased OPAL in OSA subjects may enhance Airway-collapse vulnerability, more so with greater disease severity, and partially underlie male vs female susceptibility to the sleep disorder.
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epiglottis cross sectional area and Oropharyngeal Airway length in male and female obstructive sleep apnea patients
Nature and Science of Sleep, 2016Co-Authors: Melinda A, Rajesh Kumar, Paul M Macey, Frisca L Yango, Ronald M HarperAbstract:Author(s): Ma, Melinda A; Kumar, Rajesh; Macey, Paul M; Yan-Go, Frisca L; Harper, Ronald M | Abstract: Obstructive sleep apnea (OSA) is a male-predominant condition, characterized by repeated upper-Airway collapse with continued diaphragmatic efforts during sleep, and is accompanied by severe physiological consequences. Multiple morphological aspects, including epiglottis cross-sectional area (CSA) and Oropharyngeal Airway length (OPAL), can contribute to Airway collapsibility in the condition. This study focused on the effects of OSA severity, sex, and race on OPA dimensions.Two high-resolution T1-weighted image series were collected from 40 mild-to-severe OSA subjects (age 46.9±9 years, body mass index 30.4±5.4 kg/m2, Apnea-Hypopnea Index score 32.8±22.5, 28 males) and 54 control subjects (47±9 years, 24.7±3.8 kg/m2, 32 males) using a 3 T magnetic resonance-imaging scanner. Caucasian, Asian, African-American, and "other" subjects constituted the study pool. Both image series were realigned and averaged, and reoriented to a common space. CSA and OPAL were measured, normalized for subject height, and compared between sexes and disease-severity levels in OSA and control subjects.Significantly reduced epiglottis CSA appeared only in severe OSA vs controls (P=0.009). OPAL increased significantly with OSA severity vs controls (mild, P=0.027; moderate, Pl0.001; severe, Pl0.001). OSA males showed increased CSA and greater OPAL than OSA females, which may underlie the increased proportion of affected males with higher apnea-hypopnea index scores. However, no significant differences appeared between CSA and OPAL measures for male and female controls, suggesting that Airway morphology may not be the sole contributor for Airway collapse. No ethnic or racial differences appeared for CSA or OPAL measures.Sex-based reductions in epiglottis CSA and increased OPAL in OSA subjects may enhance Airway-collapse vulnerability, more so with greater disease severity, and partially underlie male vs female susceptibility to the sleep disorder.
Makoto Tanaka - One of the best experts on this subject based on the ideXlab platform.
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propofol requirement for insertion of cuffed Oropharyngeal Airway versus laryngeal mask Airway with and without fentanyl a dose finding study
BJA: British Journal of Anaesthesia, 2003Co-Authors: Makoto Tanaka, Toshiaki NishikawaAbstract:Background The cuffed Oropharyngeal Airway (COPA) is a modified Guedel-type oral Airway with a cuff at its distal end. The objectives of this prospective, randomized study were to compare the COPA and the laryngeal mask Airway (LMA † †LMA ® is the property of Intavent Limited.) in terms of propofol requirement with and without fentanyl pretreatment for smooth insertions. Methods Seventy-five patients undergoing general anaesthesia were randomly assigned to either a COPA ( n =38) or LMA ( n =37) group for Airway management, and each group was further randomized to a saline-propofol or fentanyl-propofol group for anaesthesia induction. The saline-propofol group received i.v. saline and the fentanyl-propofol group received i.v. fentanyl 1 μg kg −1 followed 30 s later by i.v. propofol. Insertion of the device was attempted 90 s after propofol administration without the use of neuromuscular blocking agents or other adjuvants, and the responses of ‘movement' or ‘no movement' were judged by three observers blinded to the drug dose. Each dose of propofol at which insertion was attempted was predetermined by modification of Dixon's up-and-down method with 0.5 mg kg −1 as the step size, and 2 mg kg −1 as an initial dose. Results Without fentanyl pretreatment, propofol requirement [mean (sd), 95% CI] for COPA placement [2.17 (0.38), 1.77–2.56 mg kg −1 ] was significantly less than for LMA insertion [3.42 (0.26), 3.15–3.69 mg kg −1 , P −1 , respectively], but were less than for the placebo group with both devices ( P Conclusions Insertion of the COPA can be accomplished with a smaller bolus dose of propofol compared with the LMA, but propofol requirements are similar with both devices after a small dose of fentanyl.
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minimum alveolar sevoflurane concentrations required for insertion of the cuffed Oropharyngeal Airway and the laryngeal mask Airway a comparative study
Anaesthesia, 1999Co-Authors: Makoto Tanaka, S. Watanabe, Toshiaki NishikawaAbstract:Both the cuffed Oropharyngeal Airway and the laryngeal mask Airway share a similar property of being less stimulating to the upper Airway than the tracheal tube. This study was conducted to compare sevoflurane concentrations required for insertion of the cuffed Oropharyngeal Airway and the laryngeal mask Airway in elderly and young adult patients. Forty-one elderly (65-90 years) and 34 young adult (18-5() years) patients, scheduled for elective surgery during spontaneous breathing anaesthesia were randomly assigned to either the cuffed Oropharyngeal Airway or the laryngeal mask Airway group. After a predetermined end-tidal concentration of sevoflurane had been established and maintained for at least 20 min, insertion of the device was attempted without neuromuscular relaxants or other adjuvants. Each concentration at which insertion of the device was attempted was predetermined by modification of Dixon's up-and-down method with 0.5% as the step size. Sevoflurane MAC COPA [mean 1.17 (SD 0.38)%, 0.77-1.56% (95% CI)] was significantly less than MAC LMA [2.00 (0.52)%, 1.45-2.55%, p<0.05] for elderly patients. Similarly, sevoflurane MAC COPA [1.33 (0.38)%, 0.94-1.73%] was significantly less than MAC LMA [2.00 (0.42)%, 1.56-2.44%, p<0.05] for young adult patients. There were no significant differences in either MAC COPA or MAC LMA between the elderly and the young adult patients. We conclude that the insertion of the cuffed Oropharyngeal Airway can be accomplished at a lower sevoflurane concentration, and hence, is less stimulating to the upper Airway than that of the laryngeal mask Airway.
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Minimum alveolar sevoflurane concentrations required for insertion of the cuffed Oropharyngeal Airway and the laryngeal mask Airway: a comparative study.
Anaesthesia, 1999Co-Authors: Makoto Tanaka, S. Watanabe, Toshiaki NishikawaAbstract:Both the cuffed Oropharyngeal Airway and the laryngeal mask Airway share a similar property of being less stimulating to the upper Airway than the tracheal tube. This study was conducted to compare sevoflurane concentrations required for insertion of the cuffed Oropharyngeal Airway and the laryngeal mask Airway in elderly and young adult patients. Forty-one elderly (65-90 years) and 34 young adult (18-5() years) patients, scheduled for elective surgery during spontaneous breathing anaesthesia were randomly assigned to either the cuffed Oropharyngeal Airway or the laryngeal mask Airway group. After a predetermined end-tidal concentration of sevoflurane had been established and maintained for at least 20 min, insertion of the device was attempted without neuromuscular relaxants or other adjuvants. Each concentration at which insertion of the device was attempted was predetermined by modification of Dixon's up-and-down method with 0.5% as the step size. Sevoflurane MAC COPA [mean 1.17 (SD 0.38)%, 0.77-1.56% (95% CI)] was significantly less than MAC LMA [2.00 (0.52)%, 1.45-2.55%, p