Demographics, clinical history, difficult airway predictors, intraoperative management and LMA failure were included. At the beginning of the day Case Report Forms (CRFs) were distributed in every operating room. In case of using ProSeal™ LMA, they were filled by the attending anesthesiologist, resident of anesthesiology or medical student, not associated investigators of this research. At the end of the day CRFs were collected by authors who then entered the information into electronic database available at the institutional digital platform. The attending anesthesiologist decided the airway management solution for every patient as they did during their daily clinical practice. When ProSeal™ LMA was used the size was chosen, usually, depending on patient's weight according to manufacturer's recommendations (LM instruments S.A., Bogotá, Colombia). Cuff insufflate volume was chosen by the anesthesiologist without exceeding manufacturer's recommended volumes or up to 60 cmH2O measured with manometer.27
To define LMA failure, definitions by different authors were considered and are shown in Table 2. Therefore, it was decided to include the main characteristics of found descriptions: need to exchange to another device, time and dysfunctionality. LMA failure for this research was then defined as the presence of gas leakage that does not allow reaching the programmed volume or ventilatory pressure from the start of ventilation until 5 minutes after its implantation, requiring change in LMA size or insertion of an orotracheal tube.
This research follows international laws for biomedical investigation for the World Health Organization entrusted in Helsinki Declaration, and it is regulated by Resolution No. 8430 of 1993 by Colombian Health Ministry. According to established risk categories, research was considered without risk given its documental character where authors did not assign biologic, psychologic or social exposures to patients different from the ones required for their surgical procedures. This research has Institutional Review Board approval in Fundación Valle del Lili with internal certificate no. 06 of March 22, 2017, therefore, the ethics committee decided to exempt informed consent.
Statistical analysis was performed using statistical software STATA 12.1 (StataCorp. 2011, Stata Statistical Software: Release 12; StataCorp LP, College Station, TX). Incidence of ventilatory failure with ProSeal™ LMA was calculated taking the number of failures over the total of anesthetic procedures included in the research period.
Continuous variables were expressed as mean and standard deviation or median and interquartile range (IQR), according to assumption of normal distribution. Categorical variables were presented as proportions and the comparison between them was made with Fisher's exact test or Chi2 depending on procedure's distribution for each category, considering a statistical significance as a P value <0.05. Results were shown in frequency tables.
For multivariate analysis skewed logistic regression was used to estimate adjusted odd ratios (ORs). This method is useful when there are extreme probabilities, that is, when for the outcome variable a greater proportion is presented in one of the categories. Under this scenario, the use of a classic logistic regression is not adequate, since it assumes that the probability of failure is 50%,28 which does not occur in this research because the probability was 5.2%.
This regression includes variables with a P value <0.15 in the bivariate analysis. The variables were selected using the Backward method and for each model the Akaike information criterion (AIC) and the Bayesian information criterion (BIC) were calculated in order to evaluate the goodness-of-fit. The model with the lowest AIC or BIC value was chosen in the selection of variables.
A total of 500 procedures were included (Fig. 1). Median age was 51 years (IQR 37.0–65.0 years) and 26 for body mass index (IQR 23.6–28.4). The majority were women (62.2%) and LMA size most frequently used was 4 (68.2%) (Table 3).
Incidence of ventilatory failure with ProSeal™ LMA was 5.2% (26 out of 500 procedures). Age (P = <0.001), Mallampati Classification (P = 0.002), reduced neck movements (P = 0.025), edentulous (P = 0.001), use of neuromuscular blockers (NMB) (P = 0.024) and inadequate anesthetic depth, and/or laryngospasm (P = 0.001) were statistically significant related factors among the group that presented ventilatory failure (Table 4). Failure was more frequent in patients older than 75 years, while those who did not present failure occurred in greater proportion under 60 years. Patients without failure had Mallampati Classification I more frequently, and those with failure had Classification III and IV. It is more frequent that patients with ventilatory failure be edentulous, with reduced neck movements, intraoperative use of NMB and present inadequate anesthetic depth, and/or laryngospasm.
Later with the Skewed logistic regression more parsimonious model it was found that the age (OR = 1.06, 95% CI 1.03–1.09, P < 0.001), thyromental distance less than 6 cm (OR = 2.48, 95% CI 0.93–6.62, P = 0.069), inadequate anesthetic depth and/or (OR = 5.78, 95% CI 2.23–14.96, P < 0.001) and intraoperative use of NMB (OR = 2.35, 95% CI 1.06–5.21, P = 0.035) were associated factors for LMA ventilation failure. Results of this model are presented in Table 5.
Ventilatory failure with ProSeal™ LMA in patients seen in Fundación Valle del Lili was 5.2%, being higher than reported for Classic and Unique LMA.9,17,18,25,26 Ramachandran et al25 described a 1.1% incidence of failure with Unique LMA in more than 15,000 anesthetic procedures and Saito et al17,18 reported 0.2% with different types of LMA. However, the incidence estimated with this research remains being low compared with the estimated for the overall of patients in which any type of LMA is being used.
We identified that patients older than 75 years, edentulous, with Mallampati Classification III or more, reduced neck movements, short thyromental distance, use of NMB and inadequate anesthetic depth, and/or laryngospasm had a greater opportunity to develop ventilatory failure with ProSeal™ LMA. It is proposed to evaluate the presence of these clinical characteristics, in order for the professional be prepared with other airway devices and improves patient's conditions to achieve a successful airway management.
This research identified that the older the population was, the proportion of patients with ventilatory failure increases. Result consistent with authors like Ramachandran et al25 and Saito et al17 who identified the age as risk factor for failure, specifically being older than 45 years.18 This relation can be explained by the structural changes in this population's upper airways, which is more elliptical and less firm compared to younger people.29
To secure the airway correctly, the anatomy of patients should allow an alignment of the oropharynx and fixation of the LMA to the hypopharynx. That may be limited if the patient has a short thyromental distance and poor neck mobility, both reported as risk factors for LMA failure in the literature.17,18,20,25 In this research at first bivariate analysis they were proven significant, and even though the thyromental distance less than 6 cm entered the logistic regression model, they both failed to demonstrate statistical significance at the end. In a clinical setting they are usually considered important together to achieve an adequate positioning of the patient and it is very difficult to distinguish which could be more determinant for an easier insertion of the device.17,18
Although an adequate anesthetic depth is considered essential for a successful LMA insertion,1 in the literature reviewed an insufficient anesthetic depth and/or presence of laryngospasm have not been considered an isolated factor associated with failure of supraglottic devices.17,18,25 We identified that having an inadequate anesthetic depth and/or presence of laryngospasm represents a 5 times greater opportunity to develop ventilatory failure. This finding could be due to the possibility that the patient bites the device, moving it and not permitting an adequate seal. In addition, it could generate laryngospasm, which avoids airflow to the lungs, altering oxygenation, and finally leading to device failure.
It is well known the need of NMB for insertion and functioning of the orotracheal tube, but their role for LMA use remains controversial. Recent clinical trials have shown no differences in terms of seal pressures, surgical conditions, and pharyngolaryngeal discomfort with ProSeal™ LMA when NMB are used or not, but with longer recovery times when they are used.30,31 We identified a statistical significant relation between ventilatory failure and intraoperative use of NMB, where the opportunity of developing failure is 2 times greater when they are used. This intriguing finding favors the latest tendency in the literature that NMB are not necessary for LMA positioning,17,30,31 even though in the clinical setting we can evidence improving anesthetic conditions for LMA insertion with their use. This can be explained by changes in upper airway structure when patients are anesthetized and paralyzed compared with conscious patients, evidenced through radiological examinations by Sivarajan and Joy.32 These structures move backwards with head extension leading to oropharynx narrowing and possibly making the LMA insertion harder.
We identified no statistically significant relation between being edentulous and LMA ventilatory failure, even though a higher proportion of failure was seen with this condition. This is congruent with some reported research in which having lesser dental pieces was associated with this device failure,20,25,33 and may be due to increased laxity in pharynx tissues, which prevents an adequate fixation of the device, facilitating its displacement and allowing air leakage as an insufficient seal is obtained, generating greater difficulty for airway management.23,25,33–35
For explaining the differences between genders, many research has described the increased resistance of a male's upper airway compared to a female's, leading to a narrow lumen and airway obstruction.20,25,34 This condition could predispose male patients to failure with a supraglottic device explaining the significant relation observed in recent investigations,17,25 however for this research failed to prove significance.
History of pulmonary pathology was considered if the patient had chronic obstructive pulmonary disease, asthma, or obstructive sleep apnea syndrome. Decrease in lung compliance and increase airflow resistance through the lungs are pathophysiological changes described in these conditions that can generate high airway pressures with subsequent possibility for oropharyngeal leakage and leading to failure.20,25,34 Nevertheless, it was not possible to demonstrate a statistically significant relation.
Despite the fact that the experience of the person managing the airway has been considered as a risk factor for the failure of orotraquel intubation,20 this variable was included in the analysis, without statistical relation among the staff that inserted the device, including students of medicine, residents and anesthesiologists. Result compatible with the exposed by Ramachandra et al.25
Results of this research contribute to medical literature with the identification of related clinical conditions to ventilatory failure with ProSeal™ LMA in patients seen in a high-complexity hospital in Cali, Colombia, where in addition to other known factors, we obtained a statistical significant relation between an inadequate anesthetic depth and/or presence of laryngospasm with this device ventilatory failure, being described for the first time in these investigations. It is proposed that in case of identifying any associated factor for failure, the anesthesiologist should be prepared with other devices such as orotracheal tubes, video-laryngoscope or fiberscope, in order to effectively manage failure and avoid its complications like hypoxemia, brain injury and even death.
The main limitation was the amount of patients that presented the event, even though a multivariate analysis with skewed logistic regression was carried out.
Álvaro Ignacio Sánchez Ortiz, MD, PhD; Associated researcher—Clinical Research Centre (CIC); Fundación Valle del Lili—Cali, Colombia; Darío Alberto Castaño Ramírez, MD; Clinical Research Centre (CIC); Fundación Valle del Lili—Cali, Colombia.
This research follows international laws for biomedical investigation for the World Health Organization (WHO) entrusted in Helsinki Declaration, and it is regulated by Resolution No. 8430 of 1993 by Colombian Health Ministry. According to established risk categories, research was considered without risk given its documental character where authors did not assign biologic, psychologic or social exposures to patients different from the ones required for their surgical procedures, therefore, the ethics committee decided to exempt informed consent. This research has Institutional Review Board approval in Fundación Valle del Lili with internal certificate no. 06 of March 22, 2017.
The research was funded by Fundación Valle del Lili and Universidad Icesi.
Conflicts of interest
Authors have no conflicts of interest to disclose.
1. Brain AIJ, London T. The laryngeal mask—a new concept in airway management
. Br J Anaesth 1983;55:801–805.
2. Kannan S, Harsoor S, Sowmiya L, et al Comparison of ventilatory efficacy and airway dynamics between ProSeal laryngeal mask airway and endotracheal tube in adult patients during general anesthesia. J Anaesthesiol Clin Pharmacol 2015;31:517.
3. Brain AJ, Verghese C, Strube PJ. The LMA ‘ProSeal’—a laryngeal mask with an oesophageal vent. Br J Anaesth 2000;84:650–654.
4. Hagberg C. Benumof's airway management
: principles and practice. 2nd edition.2007;Mosby, Philadelphia, PA:p 449–459.
5. Stendall C, Glaisyer H, Liversedge T, et al Paediatric supraglottic airway devices update. Colombian Journal of Anesthesiology
2017;5 (suppl. 2):39–50.
6. Maitra S, Baidya DK, Arora MK, et al Laryngeal mask airway ProSeal provides higher oropharyngeal leak pressure than i-gel in adult patients under general anesthesia: a meta-analysis. J Clin Anesth 2016;33:298–305.
7. Maitra S, Khanna P, Baidya DK. Comparison of laryngeal mask airway Supreme and laryngeal mask airway Pro-Seal for controlled ventilation during general anaesthesia in adult patients: systematic review with meta-analysis. Eur J Anaesthesiol 2014;31:266–273.
8. Wong DT, Yang JJ, Jagannathan N. The LMA Supreme™ supraglottic airway. Can J Anesth 2012;59:483–493.
9. Shin WJ, Cheong YS, Yang HS, et al The supraglottic airway I-gel in comparison with ProSeal laryngeal mask airway and classic laryngeal mask airway in anaesthetized patients. Eur J Anaesthesiol 2010;27:598–601.
10. Francksen H, Renner J, Hanss R, et al A comparison of the i-gelTM
with the LMA-UniqueTM
in non-paralysed anaesthetised adult patients. Anaesthesia 2009;64:1118–1124.
11. Jadhav P, Dalvi N, Tendolkar B. I-gel versus laryngeal mask airway-Proseal: comparison of two supraglottic airway devices in short surgical procedures. J Anaesthesiol Clin Pharmacol 2015;31:221.
12. Timmermann A. Supraglottic airways in difficult airway management
: successes, failures, use and misuse. Anaesthesia 2011;66 (suppl. 2):45–56.
13. Katz JA. 4th National Audit Project of the Royal College of Anaesthetists and The Difficult Airway Society. Anesthesiology
14. Keith Rose F, Cohen MM. The airway: problems and predictions in 18,500 patients. Can J Anesth 1994;41:372–383.
15. Hagberg C, Georgi R, Krier C. Complications of managing the airway. Best Pract Res Clin Anaesthesiol 2005;19:641–659.
16. Vissers RJ, Gibbs MA. The high-risk airway. Emerg Med Clin North Am 2010;28:203–217.
17. Saito T, Liu W, Chew STH, et al Incidence of and risk factors
for difficult ventilation via a supraglottic airway device in a population of 14 480 patients from South-East Asia. Anaesthesia 2015;70:1079–1083.
18. Saito T, Chew STH, Liu WL, et al A proposal for a new scoring system to predict difficult ventilation through a supraglottic airway. Br J Anaesth 2016;117:i83–i86.
19. Jeffrey A, Hagberg C. Practice guidelines for management of the difficult airway. Anesthesiology
20. Mauricio I, Arteaga A. Update on difficult airway management
with a proposal of a simplified algorithm, unified and applied to our daily clinical practice [Actualización en vía aérea difícil y propuesta de un algoritmo simple, uni fi cado y aplicado a nuestro medio]. Colombian Journal of Anesthesiology
21. Berkow LC. Strategies for airway management
. Best Pract Res Clin Anaesthesiol 2004;18:531–548.
22. N⊘rskov AK, Rosenstock CV, Wetterslev J, et al Incidence of unanticipated difficult airway using an objective airway score versus a standard clinical airway assessment: the DIFFICAIR trial—trial protocol for a cluster randomized clinical trial. Trials 2013;14:347.
23. Frerk C, Mitchell VS, McNarry AF, et al Difficult Airway Society 2015 guidelines for management of unanticipated difficult intubation in adults. Br J Anaesth 2015;115:827–848.
24. Castro-Gómez A, Delgado A. Tracheal intubation in the prone position: Another way to access the airway. Colombian Journal of Anesthesiology
25. Ramachandran SK, Mathis MR, Tremper KK, et al Predictors and clinical outcomes from failed Laryngeal Mask Airway Unique™: a study of 15,795 patients. Anesthesiology
26. Brimacombe JR, Verghese C. Survey of laryngeal mask airway usage in 11,910 patients: safety and efficacy for conventional and nonconventional usage. Anesth Analg 1996;82:129–133.
27. Asai T, Brimacombe J. Cuff volume and size selection with the laryngeal mask. Anaesthesia 2000;55:1179–1184.
28. Freeman J, Jackman S, Jackson J. Scobit: an alternative estimator to logit and probit. Am J Pol Sci 1994;38:230–255.
29. Abramson Z, Susarla S, Troulis M, et al Age-related changes of the upper airway assessed by 3-dimensional computed tomography. J Craniofac Surg 2009;20 (suppl. 1):657–663.
30. Na HS, Jeon YT, Shin HJ, et al Effect of paralysis at the time of ProSeal laryngeal mask airway insertion on pharyngolaryngeal morbidities. A randomized trial. PLoS One 2015;10:1–9.
31. Chen BZ, Tan L, Zhang L, et al Is muscle relaxant necessary in patients undergoing laparoscopic gynecological surgery with a ProSeal LMATM? J Clin Anesth 2013;25:32–35.
32. Sivarajan M, Joy J. Effects of general anesthesia and paralysis on upper airway changes due to head position in humans. Anesthesiology
33. Genez M, Küçükgüçlü S, Özbilgin Ş, et al A comparison of usage of the laryngeal mask uniqueTM
in denticulate and edentulate geriatric patients. Turk J Med Sci 2017;47:854–860.
34. Mohsenin V. Gender differences in the expression of sleep-disordered breathing: role of upper airway dimensions. Chest 2001;120:1442–1447.
35. Butterworth J, Mackey D, Wasnick J. Morgan & Mikhail's clinical anesthesiology
. Anesth Analg 2013;75:907–917.
Ventilatory depression; Risk factors; ProSeal™ laryngeal mask; Airway management; Anesthesiology; Depresión ventilatoria; Factores de riesgo; Máscarilla laríngea ProSeal™; Manejo de las vías respiratorias; Anestesiología
Supplemental Digital Content
© 2019 by Lippincott Williams & Wilkins, Inc.