Anesthesiology ALN SPECIAL ARTICLE ANET anet ABSTRACT aln This fourth and last installment of my history of basic airway management dis- cusses the current (i.e., “modern”) era of anesthesia and resuscitation, from 1960 to the present. These years were notable for the implementation of inter- ALN An Anesthesiologist’s mittent positive pressure ventilation inside and outside the operating room. Basic airway management in cardiopulmonary resuscitation (i.e., expired air Perspective on the ventilation) was de-emphasized, as the “A-B-C” (airway-breathing-circula- ALN tion) protocol was replaced with the “C-A-B” (circulation-airway-breathing) History of Basic Airway intervention sequence. Basic airway management in the operating room 0003-3022 (i.e., face-mask ventilation) lost its predominant position to advanced airway Management management, as balanced anesthesia replaced inhalation anesthesia. The one-hand, generic face-mask ventilation technique was inherited from the 1528-1175 The “Modern” Era, 1960 to Present progressive era. In the new context of providing intermittent positive pres- sure ventilation, the generic technique generated an underpowered grip with Lippincott Williams & WilkinsHagerstown, MD Adrian A. Matioc, M.D. a less effective seal and an unspecified airway maneuver. The significant advancement that had been made in understanding the pathophysiology of ANESTHESIOLOGY 2019; 130:00–00 upper airway obstruction was thus poorly translated into practice. In contrast 10.1097/ALN.0000000000002646 to consistent progress in advanced airway management, progress in basic airway techniques and devices stagnated. “Anesthetists who have not tried this two-handed ANESTHESIOLOGY 2019; 130:00–00 hyperextension manipulation will be surprised to observe the combined effects of simultaneously Special Article pushing the vertex of the head backward and pulling The generic one-hand face-mask ventilation inher- upward on the symphysis of the mandible.” ited from the progressive era (i.e., the “E-C” technique) 2019 Editorial. J Am Med Assoc 1961; 176:608–9 applied the thumb and index finger on the face mask dome (the “C”) and the rest of the fingers dispersed along the Adrian A. Matioc uring the “artisanal” anesthetic era (1846 to 1904) and mandibular body with the fifth finger at the angle of the Dthe “progressive” era (1904 to 1960), airway patency jaw (the “E”). The E-C grip and the airway management in general inhalation anesthesia was provided using basic devices that had served the anesthesia community for xxxxxxXXX airway management techniques (i.e., head extension and almost 100 yr were not reexamined or validated for use jaw thrust applied with or without a face mask).1,2 with the new positive pressure face-mask ventilation, and XXX In the 1950s and 1960s, anesthesiologists revolutionized their limitations were carried over into the modern era.3 airway management in resuscitation by demonstrating the In the “modern” anesthetic era (1960 to the present), the paradigm shift from inhalation to balanced anesthesia XXX superiority of expired air artificial ventilation techniques (e.g., mouth-to-mouth ventilation) to traditional man- and from spontaneous to positive pressure ventilation was ual methods (e.g., Silvester, Schäfer, Holger Nielsen) and implemented over several decades. Relying on spontaneous 00 initiated the implementation of positive pressure ventila- ventilation and an unprotected airway with a face mask, slow tion3 (fig. 1). In the process, they validated optimal tech- and strenuous inhalation induction was replaced by rapid intravenous induction with apnea, followed by endotracheal 00 niques for the known airway maneuvers. Head extension in resuscitation—in contrast to the operating room–was intubation. Adult inhalation anesthesia, supported by basic applied with two hands, one hand on the chin and one on airway management, became the exception. The anesthesia 13March201815August201822August2018 the vertex, mobilizing the occipitoatlantoaxial joint and provider in the modern medical center became the airway upper cervical spine in the sagittal plane. Jaw thrust—in management expert at a time when positive-pressure face- 2019 concordance with the operating room—was applied with mask ventilation morphed into a short, bridging technique, two hands on the transverse plane by subluxating both used between the time of pharmacologically induced apnea and tracheal intubation. “Cannot ventilate” was replaced by xxxxxxXXX temporomandibular joints. Both techniques elevated the chin, increased both the chin-cervical spine and chin- “cannot ventilate, cannot intubate.” sternum distances, and positioned the mandible in front Starting with the 1990s, the implementation of airway of the maxilla.4 management guidelines, complex-monitoring systems, new Submitted for publication March 13, 2018. Accepted for publication August 30, 2018. From the Department of Anesthesiology, University of Wisconsin School of Medicine and Public Health, William S. Middleton Memorial Veterans Hospital, Madison, Wisconsin. Copyright © 2019, the American Society of Anesthesiologists, Inc. Wolters Kluwer Health, Inc. All Rights Reserved. Anesthesiology 2019; 130:00–00 ANESTHESIOLOGY, V 130 • NO XXX XXX 2019 1 LWW Copyright © 2019, the American Society of Anesthesiologists,<zdoi;10.1097/ALN.0000000000002646> Inc. Wolters Kluwer Health, Inc. Unauthorized reproduction of this article is prohibited. SPECIAL ARTICLE context, optimizing advanced airway management devices and techniques has been prioritized and recognized as criti- cal because of the reduced apnea tolerance of obese patients. This article, the fourth in the series, follows the evolu- tion of adult basic airway management from 1960 to the present in the Western world. Development of Western Medicine in the Modern Era Surgery and Medicine. In the modern era, surgery contin- ued its rapid progress. Technology and newly developed sur- gical techniques allowed pediatric and adult cardiac surgery, transplantations of organs, implantation of organs engineered in the laboratory, and minimally invasive surgeries (e.g., robot- ics).10 One essential achievement of the profession was the “democratization” of surgery, meaning that in recent decades surgery established itself as “an essential tool for helping people live long and healthy lives,” increasing the number of opera- tions performed annually in the United States to 50 million.11 Surgeons are involved in nonelective airway management out- side the operating room—with a focus on “definitive” endo- tracheal intubation and surgical airway—as organizers and teachers of the Advanced Trauma Life Support courses.12 Medicine continued to develop in the early modern era along the progressive era scientific directions, whereas in the second half of the modern era, molecular biology, immunotherapy, genetics, and advances in technology and pharmacology provided new approaches for the control and cure of disease. Additionally, new invasive branches of med- ical practice (cardiovascular, digestive, hepatology, neurol- ogy) grew, requiring anesthesia support.13 Along with these Fig. 1. The early evaluation of mouth-to-mouth ventilation and advancements came new challenges: iatrogenic complica- validation of head extension as a two-hand technique by Peter tions and resistance to antimicrobial therapy.14 As well, med- Safar at the Baltimore City Hospital. Reprinted from Baskett ical practitioners became involved in Basic and Advanced PJF: Peter J. Safar, the early years 1924 to 1961, the birth of CPR. Resuscitation 2001; 50:17–22 with kind permission from Life Support courses and emergency medicine physicians Elsevier. and providers became involved in nonelective airway man- agement outside and inside the hospital.15 Anesthesia advanced airway management devices and techniques (e.g., Anesthetic Delivery Systems. Various anesthetic agents supraglottic airways, fiberoptic intubation, videolaryngo- and delivery systems coexisted in the early modern era.3,16 scopes), and consistent improvement in general anesthesia Open techniques involved dripping ether on a gauze-cov- techniques and training led to the dramatic fall in anesthesia ered, wire-frame mask positioned on a spontaneously 5,6 morbidity and mortality. breathing patient. This was an unsophisticated method, The 1990s also marked the start of renewed interest in not requiring a perfect face mask seal and resulting in a apneic oxygenation and extensive research into upper airway prolonged and unpredictable induction and maintenance obstruction pathophysiology, especially in obese and obstruc- of general anesthesia. Draw-over apparatuses, in which tive sleep apnea patients. Unfortunately, it did not lead to low resistance vaporizers delivered a known percentage of significant progress in basic airway management guidelines anesthetic agents, required special training (e.g., Epstein- and techniques. In the second half of the modern era, obe- Macintosh-Oxford, Penlon Draw-over, Blease Universal sity reached epidemic proportions, with more than one-third vaporizer).17 However, unlike open techniques, inhala- (36.5%) of U.S. adults and 15% to 20% of European adults tion anesthesia with draw-over apparatuses and anesthesia considered obese.7 It is estimated that by 2020, 70% to 75% machines required a perfect face-mask seal, making the of the U.S. population will be affected by obesity.8 The epi- technique laborious with elderly, edentulous, or bearded demic is also rapidly affecting developing countries.9 In this