At Stanford’s Center for Immersive and Simulation-based Learning, anesthesiologist Jordan Newmark leads a seminar for anesthesiology fellows. Roach learns why anesthesiologists intubate during surgeries: General anesthesia depresses breathing and often includes neuromuscular blockade, so the patient’s diaphragm stops working. Thus, patients need to be attached to a ventilator to continue breathing. 

The group practices on manikins. Roach follows the steps Newmark taught, like opening the jaw, advancing a laryngoscope to lift the tongue, and visualizing the vocal cords. She feels how easy it is to cause dental injury to the patient. She feeds the endotracheal tube too far into her manikin’s airway, which would ventilate only one lung.

Newmark explains key hazards. Misplaced ventilation can send air into the esophagus, inflate the stomach, trigger vomiting, and lead to aspiration and lung injury—the manikins have a simulated vomit feature for training purposes. Roach then tries bag-mask ventilation, the manual version of the ventilation machine, on herself. She gets the technique wrong and ends up merely burping. She wonders how patients with paralytic polio tolerated years of machine breathing, setting up an exploration of iron lungs, or negative-pressure ventilators.

The narrator visits a Kansas City home to spend time inside an Emerson iron lung, a device that encapsulates the user’s entire body and forces them to breathe via negative pressure (changing the pressure of the environment). This forces the patient’s chest cavity in and out, which makes the lungs inhale and exhale. This particular iron lung was once used by Mona Randolph, a polio survivor. Mark Randolph, Mona’s husband, describes the daily routine he used to move her and care for her needs. 

Roach wants to have her dinner inside the iron lung since this is what polio patients had to do. Caregiver Jane Buckley cautions her not to eat inside the machine because it dictates inhale timing and can cause aspiration. They set the neck seal and start the motor. The narrator panics at the sensation of machine-controlled deep breaths as well as the collar tightening around her neck, and she asks to come out after only minutes. Jane recalls that Mona was always relieved to enter the contraption at night, when negative pressure rested her diaphragm.

Historical context fills in how negative-pressure ventilation arose, from 1840s demonstrations to widespread iron-lung use during polio epidemics. As polio vaccination succeeded, critical care shifted to positive-pressure ventilators. Dr. Norma Braun explains how intubation blocks speech and swallowing and introduces oral bacteria, contributing to pneumonia. Positive pressure—when air is forcefully introduced directly into the lungs— overinflates upper lung regions and underinflates bases, which lowers oxygenation and leaves zones for infection. Dr. C. Lee Cohen explains how clinicians balance pressure against risk of alveolar rupture in stiff lungs, often resorting to sedation and paralysis, which weakens muscles.

Clinicians now consider simpler negative-pressure options. The UK’s Exovent encloses only the chest. Braun shows a wearable prototype, the Venti, a chest shell with a pump that provides a gentler assist. Negative-pressure devices are inexpensive and simple, which can expand access and, in select patients, reduce complications tied to tubes and high-pressure inflations.

The narrator travels to Mongolia to study cataract surgery with a nonprofit organization called Orbis International. Heading toward Khuvsgul province, they detour to a nomadic family’s ger, or home, where they glimpse the economics of herding and life under intense sunlight. The team continues to Murun General Hospital, one of seven provincial hubs where Orbis equips facilities and trains surgeons, a more sustainable approach than flying in visiting teams.

The Murun operating room is spare but adequate for manual small-incision cataract surgery. An Orbis-trained ophthalmologist operates while a local surgeon observes. The standard, high-tech procedure in modern hospitals is called phacoemulsification, but lacking equipment, Orbis surgeons do it a bit differently: The surgeon removes the cataract through a self-sealing small incision. 

The chapter traces cataract treatment history: Ancient protocol was “couching,” which pushed the lenses downward instead of removing them. Extracapsular extraction was used in the 18th-20th centuries, featuring large incisions that required long bedrest afterward, and Harold Ridley’s insight into well-tolerated Plexiglas fragments seeded modern intraocular lenses (IOLs). In regions like rural Mongolia, the manual small-incision technique offers low cost, simple training, and manageable complications.

The next day, a herder returns for her bandage removal. One day after surgery, she performs a vision test. Roach is struck by her bowlegged gait when the woman eventually stands up, thinking how this underscores how critical sight is for the woman’s life, full of work and caregiving. 

On the drive back, the group discusses why presbyopia develops: The lens stiffens with age, losing the ability to change focus. Dr. Julie Schallhorn reviews the challenging record of accommodating IOLs that aim to mimic natural focusing, noting that designs have not achieved dependable results. In Mongolia’s rural operating rooms, simple monofocal IOLs, delivered by trained local surgeons, restore dependable vision.