Journal of Clinical Anesthesia (2014) xx, xxx–xxx
Correspondence
Airway sealing pressure behavior of the Laryngeal Mask Airway Supreme in patients undergoing surgery with general anesthesia: a pilot study☆ To the Editor: The airway sealing pressure of the Laryngeal Mask Airway (LMA) Supreme has been reported to range from 21 to 39 cmH2O [1-5]. Some authors have suggested a relationship between intracuff pressure and oropharyngeal leak pressure. It is believed that an increase in intracuff pressure might encourage an increase in oropharyngeal leak pressure [1,6]. However, a recent study showed a decrease in oropharyngeal leak pressure despite an increase in intracuff pressure during surgery [7]. Currently there is little information regarding the factors affecting airway sealing pressures of this LMA during surgical procedures. The Ethical and Investigation Committee of Nuestra Señora de Valme University Hospital, Seville, Spain, approved the study, which was conducted to determine the airway sealing pressure of the LMA Supreme in patients undergoing general anesthesia and to identify factors that may modify this pressure during surgery. All patients were informed of the study characteristics, and gave their written, informed consent. Fifty-five adult, ASA physical status 1, 2, and 3 patients who were scheduled for elective surgery during general anesthesia with a LMA were enrolled. All predictors of a difficult laryngoscope-guided tracheal intubation were recorded. Patients who had prior knowledge or were strongly suspected of a difficult tracheal intubation (a score N 11 points according to the Arné algorithm) were excluded from the study [8]. Other exclusion criteria were cervical spine disease, body mass index (BMI) ≥ 40 kg/m2 , upper respiratory or digestive tract disease, severe obstructive pulmonary disease, pregnancy, hiatal hernia, or recent history of upper respiratory tract infection. Anesthesia was induced with an intravenous administration of 2 μg/kg of 0.005% fentanyl, and 2 to 3 mg/kg of 1% propofol. Neuromuscular blocking agents were used for some patients, depending on the characteristics and duration of the surgical procedures. The insertion tech-
nique used was the one that was recommended in the instruction manual.1 The intracuff pressure was adjusted and maintained at 60 cmH2O using a calibrated cuff manometer (FIRMA AMBU, S.L. B-81040149, Madrid, Spain). A 14-French gastric tube was inserted through the drainage tube. Its correct placement was confirmed by aspiration of gastric fluid or detection of injected air by epigastric auscultation. Anesthesia was maintained with 2% sevoflurane in an airoxygen mixture using a circle system with a fresh gas flow of 2 L/min. Additional fentanyl was administered as needed during anesthesia, as indicated by a 20% increase in blood pressure or heart rate. The airway sealing pressure test was performed at the beginning and end of the surgical procedures. The expiratory valve of the circle breathing system was closed with a fixed fresh gas flow of 3 L/min for recording the airway pressure at which the leak was in equilibrium with the fresh gas flow (a maximum airway pressure of 40 cmH2O was established) [9]. At the end of surgery, the anesthesiologist removed the LMA when the patient was awakened. The results are presented in Table 1 and Fig. 1. The LMA Supreme sealing pressure showed an increase of 0.43 cm H2O per unit of BMI. Both initial and final sealing pressures were higher in Group with a BMI ≥ 30 kg/m2 (Fig. 1). The greatest increase in sealing pressure was observed during surgery in obese patients (29.9 ± 5.3 cm H2O initially vs 31.5 ± 5.3 cm H2O at end) and in those receiving neuromuscular blocking agents (27.1 ± 6.4 cm H2O initially vs 29.0 ± 5.8 cm H2O at end). When neuromuscular blocking agents were not administered during the anesthetic induction, the sealing pressure was maintained almost invariably during the surgical procedures (26.9 ± 6.8 cm H2O initially vs 27.2 ± 7.1 cm H2O at end). During elective anesthesia with the LMA Supreme, an increase in airway sealing pressure occurred at the end of the surgical procedure; however, the differences in the sealing pressure found during surgery were clinically insignificant compared with those increases noted in previous studies [1]. 1
☆
Supported by departmental funding only.
0952-8180/© 2014 Elsevier Inc. All rights reserved.
The LMA Supreme. Instruction Manual. Maidenhead (UK): Intavent Orthofix, Ltd; 2007.
2
Correspondence Table 1 Patients’ characteristics and LMA Supreme sealing pressures Age (yrs) Weight (kg) Height (cm) BMI (kg/m2) Duration of anesthesia (min) Gender (M/F) ASA physical status (1/2/3) Habitual snoring or sleep apnea IG b 3.5 cm and ML b 0 IG 3.5 - 4.9 cm and ML = 0 IG ≥ 5 cm or ML N 0 Thyromental distance ( ≥ 6.5 / b 6.5 cm) Clinical symptoms of airway pathology (yes / no) Maximum range of head and neck movement (b 80° / 90° / N 100°) Mallampati class (1/2/3/4) Neuromuscular relaxant use (yes / no) Airway sealing pressure (cm H2O) initially at the end
47.5 (SD, 14.9) 71.3 (SD, 14.1) 160 (SD, 0.1) 26.4 (SD, 4.2) 54.2 (SD, 30) 16:39 (29.1:70.9) 15/27/13 (27.3/49.1/23.6) 16 (29.1) 0 22 (40) 33 (60) 52/3 (94.5/5.5)
of neuromuscular blocking agents were associated with the greatest increase in sealing pressure during surgery. Jusset T. García-Navia MD (Anesthesia Staff) Tiburcio Vázquez-Gutiérrez (Anesthesia Staff) Aurelio Cayuela MD (Epidemiology Staff) Abel Guerola-Delgado (Anesthesia Staff) Pilar Gómez-Reja (Anesthesia Staff) Mercedes Echevarría-Moreno PhD (Assistant Professor; Chairperson, Andalusian Society of Anesthesiology) Department of Anesthesiology Nuestra Señora de Valme University Hospital Seville, Spain E-mail address: [email protected]
6/49 (10.9 / 89.1)
0 / 35 / 20 (0 / 63.6 / 36.4)
26 / 21 / 8 /0 (47.3 / 38.2 / 14.5 / 0) 30 / 25 (54.5 / 45.4)
Juan J. Egea-Guerrero MD, PhD (Intensive Care Staff) Department of Intensive Care Virgen del Rocio University Hospital IBIS/CSIC/University of Seville Seville, Spain
http://dx.doi.org/10.1016/j.jclinane.2013.11.012
References 27.0 (SD, 6.5) 28.3 (SD, 6.4)
Data are means (SD) or numbers (%). IG=interincisor gap, ML=mandibular luxation.
There is some evidence to suggest that the use of neuromuscular blocking agents may alter LMA sealing pressures and result in a lower measured sealing pressure [10]. This may explain the greatest increase in sealing pressure during surgery in patients who received a neuromuscular blocking agent during induction of anesthesia. The airway sealing pressure of the LMA Supreme showed a slight increase during surgery. Obesity required a higher airway sealing pressure. Factors such as obesity and use
Fig. 1 Sealing pressure behavior of the Laryngeal Mask Airway Supreme according to patients’ body mass index.
[1] van Zundert A, Brimacombe J. The LMA Supreme–a pilot study. Anaesthesia 2008;63:209-10. [2] Seet E, Rajeev S, Firoz T, et al. Safety and efficacy of laryngeal mask airway Supreme versus laryngeal mask airway ProSeal: a randomized controlled trial. Eur J Anaesthesiol 2010;27:602-7. [3] Cook TM, Gatward JJ, Handel J, et al. Evaluation of the LMA Supreme in 100 non-paralysed patients. Anaesthesia 2009;64: 555-62. [4] Verghese C, Ramaswamy B. LMA-Supreme–a new single-use LMA with gastric access: a report on its clinical efficacy. Br J Anaesth 2008;101:405-10. [5] Timmermann A, Cremer S, Eich C, et al. Prospective clinical and fiberoptic evaluation of the Supreme laryngeal mask airway. Anesthesiology 2009;110:262-5. [6] Zhang L, Seet E, Mehta V, et al. Oropharyngeal leak pressure with the laryngeal mask airway Supreme™ at different intracuff pressures: a randomized controlled trial. Can J Anaesth 2011;58: 624-9. [7] Hosten T, Gurkan Y, Ozdamar D, Tekin M, Toker K, Solak M. A new supraglottic airway device: LMA-supreme, comparison with LMAProseal. Acta Anaesthesiol Scand 2009;53:852-7. [8] Arné J, Descoins P, Fusciardi J, et al. Preoperative assessment for difficult intubation in general and ENT surgery: predictive value of a clinical multivariate risk index. Br J Anaesth 1998;80: 140-6. [9] Keller C, Brimacombe JR, Keller K, Morris R. Comparison of four methods for assessing airway sealing pressure with the laryngeal mask airway in adult patients. Br J Anaesth 1999;82:286-7. [10] Goldmann K, Hoch N, Wulf H. Influence of neuromuscular blockade on the airway leak pressure of the ProSeal laryngeal mask airway. Anasthesiol Intensivmed Notfallmed Schmerzther 2006;41:228-32.
Correspondence
Airway sealing pressure behavior of the Laryngeal Mask Airway Supreme in patients undergoing surgery with general anesthesia: a pilot study☆ To the Editor: The airway sealing pressure of the Laryngeal Mask Airway (LMA) Supreme has been reported to range from 21 to 39 cmH2O [1-5]. Some authors have suggested a relationship between intracuff pressure and oropharyngeal leak pressure. It is believed that an increase in intracuff pressure might encourage an increase in oropharyngeal leak pressure [1,6]. However, a recent study showed a decrease in oropharyngeal leak pressure despite an increase in intracuff pressure during surgery [7]. Currently there is little information regarding the factors affecting airway sealing pressures of this LMA during surgical procedures. The Ethical and Investigation Committee of Nuestra Señora de Valme University Hospital, Seville, Spain, approved the study, which was conducted to determine the airway sealing pressure of the LMA Supreme in patients undergoing general anesthesia and to identify factors that may modify this pressure during surgery. All patients were informed of the study characteristics, and gave their written, informed consent. Fifty-five adult, ASA physical status 1, 2, and 3 patients who were scheduled for elective surgery during general anesthesia with a LMA were enrolled. All predictors of a difficult laryngoscope-guided tracheal intubation were recorded. Patients who had prior knowledge or were strongly suspected of a difficult tracheal intubation (a score N 11 points according to the Arné algorithm) were excluded from the study [8]. Other exclusion criteria were cervical spine disease, body mass index (BMI) ≥ 40 kg/m2 , upper respiratory or digestive tract disease, severe obstructive pulmonary disease, pregnancy, hiatal hernia, or recent history of upper respiratory tract infection. Anesthesia was induced with an intravenous administration of 2 μg/kg of 0.005% fentanyl, and 2 to 3 mg/kg of 1% propofol. Neuromuscular blocking agents were used for some patients, depending on the characteristics and duration of the surgical procedures. The insertion tech-
nique used was the one that was recommended in the instruction manual.1 The intracuff pressure was adjusted and maintained at 60 cmH2O using a calibrated cuff manometer (FIRMA AMBU, S.L. B-81040149, Madrid, Spain). A 14-French gastric tube was inserted through the drainage tube. Its correct placement was confirmed by aspiration of gastric fluid or detection of injected air by epigastric auscultation. Anesthesia was maintained with 2% sevoflurane in an airoxygen mixture using a circle system with a fresh gas flow of 2 L/min. Additional fentanyl was administered as needed during anesthesia, as indicated by a 20% increase in blood pressure or heart rate. The airway sealing pressure test was performed at the beginning and end of the surgical procedures. The expiratory valve of the circle breathing system was closed with a fixed fresh gas flow of 3 L/min for recording the airway pressure at which the leak was in equilibrium with the fresh gas flow (a maximum airway pressure of 40 cmH2O was established) [9]. At the end of surgery, the anesthesiologist removed the LMA when the patient was awakened. The results are presented in Table 1 and Fig. 1. The LMA Supreme sealing pressure showed an increase of 0.43 cm H2O per unit of BMI. Both initial and final sealing pressures were higher in Group with a BMI ≥ 30 kg/m2 (Fig. 1). The greatest increase in sealing pressure was observed during surgery in obese patients (29.9 ± 5.3 cm H2O initially vs 31.5 ± 5.3 cm H2O at end) and in those receiving neuromuscular blocking agents (27.1 ± 6.4 cm H2O initially vs 29.0 ± 5.8 cm H2O at end). When neuromuscular blocking agents were not administered during the anesthetic induction, the sealing pressure was maintained almost invariably during the surgical procedures (26.9 ± 6.8 cm H2O initially vs 27.2 ± 7.1 cm H2O at end). During elective anesthesia with the LMA Supreme, an increase in airway sealing pressure occurred at the end of the surgical procedure; however, the differences in the sealing pressure found during surgery were clinically insignificant compared with those increases noted in previous studies [1]. 1
☆
Supported by departmental funding only.
0952-8180/© 2014 Elsevier Inc. All rights reserved.
The LMA Supreme. Instruction Manual. Maidenhead (UK): Intavent Orthofix, Ltd; 2007.
2
Correspondence Table 1 Patients’ characteristics and LMA Supreme sealing pressures Age (yrs) Weight (kg) Height (cm) BMI (kg/m2) Duration of anesthesia (min) Gender (M/F) ASA physical status (1/2/3) Habitual snoring or sleep apnea IG b 3.5 cm and ML b 0 IG 3.5 - 4.9 cm and ML = 0 IG ≥ 5 cm or ML N 0 Thyromental distance ( ≥ 6.5 / b 6.5 cm) Clinical symptoms of airway pathology (yes / no) Maximum range of head and neck movement (b 80° / 90° / N 100°) Mallampati class (1/2/3/4) Neuromuscular relaxant use (yes / no) Airway sealing pressure (cm H2O) initially at the end
47.5 (SD, 14.9) 71.3 (SD, 14.1) 160 (SD, 0.1) 26.4 (SD, 4.2) 54.2 (SD, 30) 16:39 (29.1:70.9) 15/27/13 (27.3/49.1/23.6) 16 (29.1) 0 22 (40) 33 (60) 52/3 (94.5/5.5)
of neuromuscular blocking agents were associated with the greatest increase in sealing pressure during surgery. Jusset T. García-Navia MD (Anesthesia Staff) Tiburcio Vázquez-Gutiérrez (Anesthesia Staff) Aurelio Cayuela MD (Epidemiology Staff) Abel Guerola-Delgado (Anesthesia Staff) Pilar Gómez-Reja (Anesthesia Staff) Mercedes Echevarría-Moreno PhD (Assistant Professor; Chairperson, Andalusian Society of Anesthesiology) Department of Anesthesiology Nuestra Señora de Valme University Hospital Seville, Spain E-mail address: [email protected]
6/49 (10.9 / 89.1)
0 / 35 / 20 (0 / 63.6 / 36.4)
26 / 21 / 8 /0 (47.3 / 38.2 / 14.5 / 0) 30 / 25 (54.5 / 45.4)
Juan J. Egea-Guerrero MD, PhD (Intensive Care Staff) Department of Intensive Care Virgen del Rocio University Hospital IBIS/CSIC/University of Seville Seville, Spain
http://dx.doi.org/10.1016/j.jclinane.2013.11.012
References 27.0 (SD, 6.5) 28.3 (SD, 6.4)
Data are means (SD) or numbers (%). IG=interincisor gap, ML=mandibular luxation.
There is some evidence to suggest that the use of neuromuscular blocking agents may alter LMA sealing pressures and result in a lower measured sealing pressure [10]. This may explain the greatest increase in sealing pressure during surgery in patients who received a neuromuscular blocking agent during induction of anesthesia. The airway sealing pressure of the LMA Supreme showed a slight increase during surgery. Obesity required a higher airway sealing pressure. Factors such as obesity and use
Fig. 1 Sealing pressure behavior of the Laryngeal Mask Airway Supreme according to patients’ body mass index.
[1] van Zundert A, Brimacombe J. The LMA Supreme–a pilot study. Anaesthesia 2008;63:209-10. [2] Seet E, Rajeev S, Firoz T, et al. Safety and efficacy of laryngeal mask airway Supreme versus laryngeal mask airway ProSeal: a randomized controlled trial. Eur J Anaesthesiol 2010;27:602-7. [3] Cook TM, Gatward JJ, Handel J, et al. Evaluation of the LMA Supreme in 100 non-paralysed patients. Anaesthesia 2009;64: 555-62. [4] Verghese C, Ramaswamy B. LMA-Supreme–a new single-use LMA with gastric access: a report on its clinical efficacy. Br J Anaesth 2008;101:405-10. [5] Timmermann A, Cremer S, Eich C, et al. Prospective clinical and fiberoptic evaluation of the Supreme laryngeal mask airway. Anesthesiology 2009;110:262-5. [6] Zhang L, Seet E, Mehta V, et al. Oropharyngeal leak pressure with the laryngeal mask airway Supreme™ at different intracuff pressures: a randomized controlled trial. Can J Anaesth 2011;58: 624-9. [7] Hosten T, Gurkan Y, Ozdamar D, Tekin M, Toker K, Solak M. A new supraglottic airway device: LMA-supreme, comparison with LMAProseal. Acta Anaesthesiol Scand 2009;53:852-7. [8] Arné J, Descoins P, Fusciardi J, et al. Preoperative assessment for difficult intubation in general and ENT surgery: predictive value of a clinical multivariate risk index. Br J Anaesth 1998;80: 140-6. [9] Keller C, Brimacombe JR, Keller K, Morris R. Comparison of four methods for assessing airway sealing pressure with the laryngeal mask airway in adult patients. Br J Anaesth 1999;82:286-7. [10] Goldmann K, Hoch N, Wulf H. Influence of neuromuscular blockade on the airway leak pressure of the ProSeal laryngeal mask airway. Anasthesiol Intensivmed Notfallmed Schmerzther 2006;41:228-32.
