Although neurocritical care as a subspecialty is a relatively young field of medicine, its origins can be traced back to ancient times. This article focuses on the progression of neurocritical care from prehistoric trepanation procedures, through the development of mechanical ventilation, management of increased intracranial pressure, and traumatic brain injury, to the establishment of the first “real” intensive care units, and finally to modern monitoring in neurocritical care, management of post-cardiac arrest patients, and the diagnosis of brain death. This article also focuses on the future direction of neurocritical care.

Keywords

Neurocritical care

Critical care

Neurology

Head trauma

Intracranial pressure

Key points

Historical aspects

The history of neurocritical care begins in antiquity, as documented in the Edwin Smith surgical papyrus. This text, named for a nineteenth century Egyptologist who purchased the document in Luxor or Thebes in 1862, is an unfinished textbook on bodily injuries written circa 1700 BC. It is believed to be a copy of an original article written 1000 years prior and describes 48 case reports, including 27 head injuries and 6 spinal cord injuries, many with documented interventions by the investigator. The Edwin Smith papyrus is remarkable in that it not only gives the first anatomic description of the brain, cerebrospinal fluid, and meninges but also describes conditions such as tetanus and aphasia.1,2

Although this extraordinary work gives us a view of ancient medical practices, it does not mention the earliest known neurosurgical procedure of trepanation, which appears to have originated in the Neolithic Era after the discovery of a trephined skull dating back to 10,000 BC. Hippocrates, frequently hailed as the “father of medicine,” clearly documented and advocated trepanation as a management for certain head injuries including skull fractures and contusions. He also documented neuroanatomic observations, categorized different skull fractures, suggested treatment for such injuries, and recognized deleterious complications such as fever and inflammation.3 About 300 years later, Aulus Aurelius Cornelius Celsus of Alexandria promoted the work of Hippocrates, but additionally described epidural and subdural hematoma evacuation via trepanation. In the 2nd century AD, another titan in the field of medicine, Galen of Pergamon, further expanded on the technique of trepanation and described innovative new tools.4 This ancient era also heralded the initial management for spinal cord injury, and Hippocrates is credited for one of these early treatments: traction. By using an extension bench he was able to reduce spinal deformities. Celsus and Galen further advanced the understanding of the pathophysiology of spinal cord injury by recognizing that damage to the “spinal marrow” or cord, and not the vertebrae, leads to deficits.5

The medieval times following the flourishing of science and medicine in the Greco-Roman epoch lacked major advances, excepting those described by one famous Persian intellectual, Avicenna. His Canon of Medicine was used as a medical text throughout Europe up until the eighteenth century,6 and he may have been the first to realize that stroke was due to blockage of the cerebral vessels, offering remedies for management of acute stroke including venesection.7

Mechanical ventilation and the birth of critical care medicine

A complete discussion of the history of mechanical ventilation is beyond the scope of this article; however, many key elements to the development of artificial respiration are relevant to critical care medicine as a subspecialty, and particularly neurocritical care. Galen first described using a bellows to ventilate a dead animal artificially through the trachea; later, the Renaissance physician Andreas Vesalius documented the use of a tracheostomy with artificial respiration by inserting a reed tube into the trachea of animals and blowing in air to observe the heart and thoracic cavity during vivisection.8 Over a century later, in 1744, the first report of positive pressure ventilation by mouth-to-mouth resuscitation was described by the surgeon William Tossach during the successful revival of a suffocated miner.9 Around the same time, several methods regarding the resuscitation of humans were in practice, including insufflating tobacco smoke through the anus and rolling a barrel against a victim’s thorax.10,11

The next great stride was in respiratory physiology with the discovery of carbon dioxide by Joseph Black. He demonstrated that carbon dioxide was the product of respiration through experiments with caustic alkali.12 The discovery of oxygen by Joseph Priestley and Carl Wilhelm Scheele soon followed through tests involving heating mercuric oxide.13 Antoine-Laurent de Lavoisier repeated these experiments and named the gas “oxygen.” He also realized that oxygen was necessary for respiration or “internal combustion.”14 By the end of the eighteenth century, bellows and pistons were favored over mouth-to-mouth resuscitation for both aesthetic reasons and concern over lack of effectiveness when using expired air containing carbon dioxide.11 Despite this trend, positive pressure ventilation was strongly criticized after experiments on drowned animals in the 1800s demonstrated emphysema when the lungs were inflated forcibly, and thus this practice fell out of favor.9,15

In the early nineteenth century, attention was directed toward negative pressure ventilation. Dr Dalziel introduced the tank respirator, which enclosed the patient in a cylindrical tube and used bellows to reduce the pressure within the tank to subatmospheric levels.15 In 1929, Drinker and Shaw published their work on a new tank respirator that used electrically operated pumps to create negative and positive pressure within the tank.16 This respirator became known as the “iron lung” and was used extensively throughout the United States to provide ventilatory support for respiratory paralysis during the poliomyelitis epidemic of the late 1940s.17 The poliomyelitis epidemic in Copenhagen in 1952 prompted the use of intermittent positive pressure ventilation. Copenhagen was overwhelmed by a large number of bulbar cases of poliomyelitis with a mortality rate of 80%.18,19 Primary credit is given to anesthesiologist, Bjørn Ibsen, who treated a patient with tracheotomy followed by manual positive pressure bag ventilation using humidified oxygen. This technique was applied to several patients, and a large staff, including 250 medical students, worked in relays to provide uninterrupted ventilation for patients. The mortality rate in Copenhagen was cut to 39%.18 Knowledge spread throughout Europe, and quickly intermittent positive pressure ventilation became standard practice.17,20

The Copenhagen poliomyelitis epidemic provided the catalyst for the development of dedicated respiratory care units—the first true intensive care units (ICUs)—to treat patients with respiratory failure of various causes, although Florence Nightingale is customarily regarded as the first to have established an ICU during the Crimean War. Nightingale clustered the sicker patients in a “monitoring unit.” Dr Dandy Walker created a specialized unit for his post-operative neurosurgical patients at the Johns Hopkins Hospital in 1929.21

With the subsequent development of respiratory and cardiac ICUs, a decrease in mortality rate between mechanically ventilated patients treated in traditional general hospitals compared with those in new ICUs was...