Prospective view for mask design

Face mask, nasal, and oral airway devices are used to secure the airway of patients in critical condition during resuscitation (1). However, without their proper operation, these devices potentially cause injury (1-4). In this article, we focus on the evolution of the face mask, and probe into the next move to improve airway management.

Evolution of the face mask

Face masks establish an air-seal around the sides of nose and mouth to connect the skin of face and bag ventilation support system. An ideal face mask should seal the skin tightly, create minimal pressure, and be least likely to increase the volume of the dead space. To achieve these goals, several types of face mask have been developed, and different airway management techniques have evolved.

Basically, a face mask consists of the body (cup), the seal (rim), a connector, and/or a strap hook. The anatomic mask (Connell mask) was the original design used to fit and create a seal over the mouth and nose. A fixed triangular or pyramidal shape might be difficult to fit on the faces of some patients, particularly those with features that deviate from the classic Caucasian features. The latex material used for the seal may cause allergy. Repeated use and cleaning results in the decay of the face mask.

The Patil-Syracuse mask is a variation of the Connell mask. In addition to the plastic material with inflated cushion rim, it has a sealed nipple or stretchable disc that allows fiberoptic airway intervention and intubation. The clear plastic allows the user to observe conditions inside the mask, is cost-effective, and enabled the creation of disposable face masks.

To reduce the dead space, the Rendell-Baker-Soucek mask was designed with a small triangular cup and no inflated cushion. It was originally designed for pediatric patients, who have more pliable facial soft tissue that allows for an effective seal.

The air-mask-bag unit mask is made of transparent plastic. With an inflatable cuff, it provides an adjustable mechanism for seal with bag ventilation, and is suitable for patients of all ages in emergencies.

Current challenges in face mask ventilation

The advancements in face mask ventilation have improved airway management; however, challenges still exist in this regard. Incidences of difficult mask ventilation (DMV) are estimated to be 0.08–13.00% and 45.9% in operating rooms and emergency departments, respectively (5-9). DMV potentially leads to severe cardiovascular collapse, cardiac arrest, hypoxic brain damage, and death (2,10). DMV also increases the risk of airway trauma, nerve injury, gastric insufflation, aspiration, vomiting, over-inflation (inflation pressures >20 cmH₂O), eye and eyelid injury, and nasal bleeding/false passage by dissecting nasal tissues (with nasopharyngeal airways) during the procedure, if the operator is not attentive to the anatomical structures under the mask (1-4). Therefore, the incidence of DMV is unacceptably high (5-9). Further improvement of mask designs is required.

Anatomical variations are the major cause for DMV. Predictors of DMV in the literature include having a beard (6,11), sunken cheeks (9), a double chin (9), lack of teeth (9,11-13), history of snoring or obstructive sleep apnea (6,11,12), limited jaw protrusion (11), a thick short neck (9), a history of neck radiation (6-8,11,12,14), a higher body mass index or weight (11,12), older age (11,12), male sex (6,12), decreased thyromental distance, and a high modified Mallampati score (3 or 4) (6,11,12). Most of the predictors of difficult airways are based on anatomical variation (6,15-18). As the number of predictors of difficulty increases, the probability of actually encountering problems increases (17-19). Hence, development of skill or devices for mask ventilation to overcome the anatomical variations is a potential resolution for DMV.

Current resolutions for difficult face mask ventilation

Airway management maneuvers and techniques

Based on the anatomic relationships, head tilt, chin lift, jaw thrust, and proper head/shoulder position to keep neck slightly extension are four simple, applicable maneuvers to improve the patency of the airway. Two-handed two-person mask ventilation, which is believed to create a more effective seal, is an alternative when encountering DMV using one-person mask ventilation. However, an increase in the pressure used to seal the face mask could cause injury to the facial skin (1,20).

Face mask adjuncts

Securing straps help keep face masks in place, and chin retainer bars support the chin from below and gently extend the head and neck. These devices create pressure to seal the face mask, maintain the airway, and also free the hands of clinicians to attend other tasks. Furthermore, seal accessory attachments are available for certain types of face masks to seal the leak between the mask and skin.

Laryngeal mask airway and cuffed oropharyngeal airway

The laryngeal mask and cuffed oropharyngeal airway are supraglottic airway devices, of intermediate intensity and invasiveness between the face mask and the endotracheal tube, and is an alternative if the facial contours of the patient are not suited for the standard face mask (21-24). On the other hand, laryngeal intubation with cuff inflation could cause malpositioning, upper airway obstruction, and an increase in airway resistance, which potentially leads to aspiration, ischemia of the pharyngeal mucosa, tongue cyanosis, bronchoconstriction, upper airway obstruction-related pulmonary edema, and inadequate ventilation (22).

Nasal mask ventilation

Nasal mask ventilation is able to create a pressure gradient between the nasopharyngeal and oropharyngeal cavities, and enhances ventilation during breathing (25,26). With limited available evidence, it may be an option in DMV, especially for those with anatomical variations that increase airway resistance (23,27).

Conclusions

The design of the face mask has been much upgraded; however, DMV still threatens the lives of patients. There are many alternative rescue methods available to establish the airway, but we are not satisfied with because of the potential complications of these methods. Future studies focusing on mask design to overcome these problems are valuable.

Acknowledgments

Funding: None.

Footnote

Conflicts of Interests: WHC serves as an Editor-in-Chief of Health Technology. The other authors have no conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.

Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.

References

1. Greenberg RS. Facemask, nasal, and oral airway devices. Anesthesiol Clin North America 2002;20:833-61. [Crossref] [PubMed]
2. El-Orbany M, Woehlck HJ. Difficult mask ventilation. Anesth Analg 2009;109:1870-80. [Crossref] [PubMed]
3. Azar I, Lear E. Lower lip numbness following general anesthesia. Anesthesiology 1986;65:450-1. [Crossref] [PubMed]
4. Bhuiyan MS, Chapman M. Mental nerve injury following facemask anaesthesia. Anaesthesia 2006;61:516-7. [Crossref] [PubMed]
5. Crosby ET, Cooper RM, Douglas MJ, et al. The unanticipated difficult airway with recommendations for management. Can J Anaesth 1998;45:757-76. [Crossref] [PubMed]
6. Kheterpal S, Martin L, Shanks AM, et al. Prediction and outcomes of impossible mask ventilation: a review of 50,000 anesthetics. Anesthesiology 2009;110:891-7. [Crossref] [PubMed]
7. Gautam P, Gaul TK, Luthra N. Prediction of difficult mask ventilation. Eur J Anaesthesiol 2005;22:638-40. [Crossref] [PubMed]
8. Langeron O, Masso E, Huraux C, et al. Prediction of difficult mask ventilation. Anesthesiology 2000;92:1229-36. [Crossref] [PubMed]
9. Lee SY, Chien DK, Huang MY, et al. Patient-specific factors associated with difficult mask ventilation in the emergency department. Int J Gerontol 2017; [Epub ahead of print]. [Crossref]
10. Ho-Tai LM, Devitt JH, Noel AG, et al. Gas leak and gastric insufflation during controlled ventilation: face mask versus laryngeal mask airway. Can J Anaesth 1998;45:206-11. [Crossref] [PubMed]
11. Kheterpal S, Han R, Tremper KK, et al. Incidence and predictors of difficult and impossible mask ventilation. Anesthesiology 2006;105:885-91. [Crossref] [PubMed]
12. Yildiz TS, Solak M, Toker K. The incidence and risk factors of difficult mask ventilation. J Anesth 2005;19:7-11. [Crossref] [PubMed]
13. Lee SY, Shih SC, Leu YS, et al. Implications of age-related changes in anatomy for geriatric-focused difficult airways. Int J Gerontol 2017;11:130-3. [Crossref]
14. Leoni A, Arlati S, Ghisi D, et al. Difficult mask ventilation in obese patients: analysis of predictive factors. Minerva Anestesiol 2014;80:149-57. [PubMed]
15. Reed M, Dunn M, McKeown D. Can an airway assessment score predict difficulty at intubation in the emergency department? Emerg Med J 2005;22:99-102. [Crossref] [PubMed]
16. Arne 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. [Crossref] [PubMed]
17. Rocke DA, Murray WB, Rout CC, et al. Relative risk analysis of factors associated with difficult intubation in obstetric anesthesia. Anesthesiology 1992;77:67-73. [Crossref] [PubMed]
18. Karkouti K, Rose DK, Wigglesworth D, et al. Predicting difficult intubation: a multivariable analysis. Can J Anaesth 2000;47:730-9. [Crossref] [PubMed]
19. Langeron O, Cuvillon P, Ibanez-Esteve C, et al. Prediction of difficult tracheal intubation: time for a paradigm change. Anesthesiology 2012;117:1223-33. [Crossref] [PubMed]
20. Fauroux B, Lavis JF, Nicot F, et al. Facial side effects during noninvasive positive pressure ventilation in children. Intensive Care Med 2005;31:965-69. [Crossref] [PubMed]
21. Beydes T, Kucukguclu S, Ozbilgin S, et al. Comparison of Laryngeal Mask Airway Supreme(TM) Versus Unique(TM) in Edentulous Geriatric Patients. Turk J Anaesthesiol Reanim 2016;44:32-6. [Crossref] [PubMed]
22. Pollack CV Jr. The laryngeal mask airway: a comprehensive review for the Emergency Physician. J Emerg Med 2001;20:53-66. [Crossref] [PubMed]
23. Saddawi-Konefka D, Hung SL, Kacmarek RM, et al. Optimizing Mask Ventilation: Literature Review and Development of a Conceptual Framework. Respir Care 2015;60:1834-40. [Crossref] [PubMed]
24. . Guidelines 2000 for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care. Part 6: advanced cardiovascular life support: section 3: adjuncts for oxygenation, ventilation and airway control. The American Heart Association in collaboration with the International Liaison Committee on Resuscitation. Circulation 2000;102:I95-104. [PubMed]
25. Oto J, Li Q, Kimball WR, et al. Continuous positive airway pressure and ventilation are more effective with a nasal mask than a full face mask in unconscious subjects: a randomized controlled trial. Crit Care 2013;17:R300. [Crossref] [PubMed]
26. Liang Y, Kimball WR, Kacmarek RM, et al. Nasal ventilation is more effective than combined oral–nasal ventilation during Induction of general anesthesia in adult subjects. Anesthesiology 2008;108:998-1003. [Crossref] [PubMed]
27. Williams WB, Jiang Y. Management of a difficult airway with direct ventilation through nasal airway without facemask. J Oral Maxillofac Surg 2009;67:2541-3. [Crossref] [PubMed]