Overview Until the early twentieth century, animal life was defined by the presence of spontaneous ventilation. Absence of breathing implied death or impending death, although experiments with resuscitation and artificial ventilation had occurred since the eighteenth century. The defining characteristics…
Overview The gases of interest to the anesthesia caregiver include oxygen (O 2 ), carbon dioxide (CO 2 ), nitrous oxide (N 2 O), and the potent volatile inhaled anesthetic agents of which desflurane, sevoflurane, and isoflurane are in common…
Overview Under normal physiologic conditions, the upper airway adds heat and moisture to inspired air to prevent drying of lower airway secretions, plugging, and mucosal injury. When dry medical gases bypass the upper airway via an endotracheal tube, the normal…
Overview Since the 1960s, the use of intermittent positive-pressure ventilation (IPPV) has become widespread during surgical and diagnostic procedures that require anesthesia. Today’s observer might wrongly conclude that the research, development, and methods for mechanical ventilation in the operating room…
Trace Concentrations of Anesthetic Gases Concern over trace concentrations of anesthetic gases dates back to 1967, when Vaĭsman reported findings of a survey of 354 anesthesiologists in Russia. All worked in poorly ventilated operating rooms (ORs) and used nitrous oxide…
Introduction The anesthesia machine serves to create a desired mixture of anesthetic gases, vapors, oxygen, and air (as well as other gases such as helium and carbon dioxide, albeit less frequently). The patient is the recipient of these prepared gas…
General Principles The term vapor describes the gaseous phase of a substance at a temperature at which the same substance can also exist in a liquid (or solid) state, below the critical temperature of that substance. Critical temperature is defined…
Anesthesia Gas Delivery System The Anesthesia Machine as a Component of an Anesthesia Workstation The modern anesthesia gas delivery system is composed of the anesthesia machine (see the following section), anesthesia vaporizer(s) (see Chapter 3 ), breathing system (see Chapter…
Overview Anesthesia providers were once expected to know a great deal about the storage and supply of medical gases. In both large and small institutions, anesthesiologists often had to rely on their own knowledge and skill in this area to…
Key Points ▪ Survival of the neonate depends on pulmonary vascular resistance transitioning from a high to a low state. PVR is increased by hypoxemia acidosis, hypothermia, and stress; inability to lower PVR in fetal circulation will not allow extrauterine…