Chapter 11: Anesthesia

INTRODUCTION

Anesthesiology is a “team sport.” Providing the best and safest care for patients depends on all members of the team—surgeons, nurses, and anesthesia providers—communicating in a timely, efficient, and patient-focused manner. Anesthesiologists today not only provide patient care in the operating room but also have patient responsibilities in other areas, including preoperative anesthesia clinics (PACs), postanesthesia care units (PACUs), obstetrics, ambulatory surgery centers, endoscopy suites, postoperative pain management, critical care units, and chronic pain management.

Anesthesia is a term derived from the Greek meaning “without sensation” and is commonly used to indicate the condition that allows patients to undergo a variety of surgical or nonsurgical procedures without the pain or distress they would otherwise experience. More importantly, this blocking of pain and/or awareness is reversible. Anesthesiology is the medical practice of providing anesthesia to patients and is most commonly provided by a medical doctor, an anesthesiologist, either alone or in conjunction with a certified registered nurse anesthetist (CRNA), anesthesia assistant, or resident physician-in-training. Anesthesia is most often described as being a general anesthetic, that is, a drug-induced loss of consciousness during which patients are not arousable even by noxious stimulus and often require a controlled airway. Anesthesia can also be provided without inducing unconsciousness by utilizing regional blockade, local anesthesia with monitored anesthesia care (MAC), or conscious sedation.

HISTORY OF ANESTHESIA

One of modern medicine’s most important discoveries was that the application of diethyl ether (ether) could provide the classic requirements of anesthesia: analgesia, amnesia, and muscle relaxation in a reversible and safe manner. Crawford Long was the first to use ether in 1842, and William Morton’s successful 1846 public demonstration of ether as an anesthetic in the “Ether Dome” of Massachusetts General Hospital ushered in the modern day of anesthesia and surgery. Chloroform was used by Sir James Y. Simpson to provide analgesia to Queen Victoria in 1853 during the birth of Prince Leopold. This royal approval of inhalation agents led to the wide acceptance of their use as surgical anesthesia. Ether (flammability, solubility) and chloroform (liver toxicity) each had significant drawbacks, and over time, inhalation agents were developed with similar anesthetic effects but much safer physiologic and metabolic properties.

Cocaine’s ability to produce topical anesthesia for ophthalmic surgery was discovered in the late 1800s. The hypodermic needle was introduced in 1890 and facilitated the injection of cocaine to produce reversible nerve blockade and later the injection of cocaine via a lumbar puncture to produce a spinal anesthetic and the first spinal headache. The chemical properties of cocaine were soon determined and manipulated to synthesize numerous other local anesthetic agents used to achieve what became known as regional anesthesia, which lacks the unconsciousness and amnesia of the general anesthetics but does produce analgesia and lack of motor movement in the “blocked” region.