The second instance of recall fascinates me. A four-year-old girl underwent a craniotomy for a brain tumor nearly a year before she entered into my care. The result of the tumor and surgery for its removal was twofold. First, the flow of cerebrospinal fluid (CSF) was obstructed, requiring a diversion procedure to prevent a possibly fatal condition. (CSF is the fluid cushion that prevents bumps to the head from causing the brain to strike the inner surface of the skull. CSF is constantly produced by the brain and must flow out of the skull to prevent fluid accumulation and increased pressure leading to brain injury.) Second, the surgery damaged the satiety center of her brain. This girl no longer felt full after eating a meal of any size. Possibly because of parental guilt for all that had happened to her, she wasn’t discouraged from gorging, and she would eat four hamburgers at a meal or an entire box of sugary cereal in the middle of the night. There is no other way to describe her appearance: she looked like a butterball turkey, her thighs so large that her feet were pushed wide apart, and her arms so hefty that her forearms didn’t touch the sides of her torso.
This girl was extremely intelligent and precocious. While she was under anesthesia for her revision surgery, and during a little OR table talk, the surgeon mentioned to me that she had experienced recall under anesthesia during the tumor resection. I asked how he knew. He said that a few days after the original craniotomy for tumor removal, during morning rounds, he had noted that this girl was on the road to recovery, fully intact, and very talkative. As he turned to leave her room, the girl had asked: “Hey Doc, what does ‘get that bleeder’ mean?”
“What?”
“What does ‘get that bleeder’ mean?”
During her operation, the surgeon, renowned for that comment—as well as “Damn it, stay with me!”—had instructed the resident assisting the surgery to use the electrocautery device to coagulate an open blood vessel. There was no possible way that a four-year-old would know this medical lingo.
I made sure that she would experience no recall during my care.
AN ABSOLUTELY MOTIONLESS PATIENT is a must during critical moments of a procedure. For a cardiologist about to burn an electrical path gone awry in a heart, or a radiologist about to dilate a narrowed blood vessel in the abdomen, or a neurosurgeon about to place a clip on a brain aneurysm that is ready to burst at any second, a movement as small as a millimeter could adversely affect the patient’s life.
Ensuring total patient stillness during these essential points in procedures has long been a goal. Its eventual means was first established centuries ago, when European explorers observed South American Indians while hunting. Using blowguns and arrows tipped in wourali poison, natives were able to bring down game animals. The method was called the Flying Death. Eventually, purification of the poison resulted in the discovery of curare, a reversible paralyzing drug first used in anesthesia for akinesia (muscle relaxation) in the 1940s. With a patient pharmacologically paralyzed, unable to voluntarily move any muscle in the body, the depth of gas anesthesia could be decreased, thereby allowing less depression of the heart and shorter time for emergence. Operating on a motionless target is critical in some procedures, such as brain surgery, but it’s also a benefit in others, leading to the oft-heard surgeon’s plea: “I need more relaxation.”
THE SEARCH FOR ANALGESIA, the relief of pain, dates back many thousands of years. Today’s potent anesthesia gases, the one-stop anesthetic, completely obliterate the presence of pain during a procedure. At some point the procedure is complete and my all-in-one gas must be turned off for the patient to return to consciousness. Another method of continuing analgesia becomes necessary. The crude methods of chewing tree bark and leaves and drinking the juice of flower seedpods evolved into the sophisticated pain relief medications that are purified and discovered in pharmaceutical and university laboratories. Willow bark evolved into aspirin, coca leaves into cocaine, and the opium-containing poppy into morphine.
In the Andes, the Incas discovered that the coca leaf holds many beneficial effects, including pleasure and numbness. Trephination—that is, drilling holes in the head, one of the earliest-known surgical procedures—was used to treat seizures, headaches, and mental ills. Inca shamans chewed coca leaves and spit into the head wounds. The cocaine contained within the leaves numbed the area and, as an added benefit, constricted blood vessels, lessening blood loss.
William Halsted, a Johns Hopkins surgeon of the 1880s and arguably the most influential modern-era surgeon, applied the concept of antisepsis to surgery, thereby vastly increasing the scope of invasive procedures. His meticulous technique required anesthesia and provided safe operative conditions. Frances Burney described at length her harrowing experience during a mastectomy without anesthesia. Few would accept Halsted’s procedures without anesthesia.
Centuries after the Inca shaman, as surgery became the norm for immediate cure, cocaine was purified and found to block nerve impulses from reaching the spinal cord and brain. Halsted took a hypodermic needle to the nerve innervating the upper jaw, injecting cocaine and creating numbness that allowed for painless oral procedures. He then found personal pleasure in cocaine and used it for recreational purpose, as did the eminent psychiatrist Sigmund Freud. Toward the end of the nineteenth century, cocaine was applied topically to the eye. Finally, cocaine was applied directly to the spinal cord to provide prolonged loss of sensation to the lower body without mental sedation—spinal anesthesia and epidural anesthesia, depending on how deep the needle is inserted between and beneath the vertebrae. Regional anesthesia was born.
Pain starts by activating a receptor at the source of the injury that transmits information to the brain as an electrical signal conducted by nerves. An insulator, the fatty membrane myelin, acts like the plastic coating on an electrical wire, preventing the loss of the signal to adjacent tissue as it travels. Breaks in the myelin called “nodes of Ranvier” enhance the speed of transmission of the pain signal by allowing the signal to jump quickly from node to node along the nerve. This rapid transmission is known as “saltatory conduction.” Cocaine enters these nodes, blocking the signal jumps and thus the transmission of the pain signal beyond that point.
The 1920s witnessed not only Prohibition, banning alcohol, but also legislation that formally banned narcotics. No longer could Mrs. Winslow’s Soothing Syrup—a morphine-laced drink offered as relief for teething toddlers—be purchased on a whim. Sales now required a prescription, creating a great example of the law of unintended consequences by leading to the formation of the black market in drugs. Narcotics remain a mainstay of my analgesia efforts, especially in treating acute pain caused by surgery or trauma. Analgesia remains sacrosanct to the anesthesiologist. But a fine line divides alleviating pain from abusing drugs, as demonstrated by the forty-eight thousand deaths that result from substance-use disorder every year in this country.
In the decades that followed the discovery of the medicinal use of cocaine, chemists, pharmacologists, and physicians dissected the coca leaf to its most basic active compounds. The knowledge gained led to the introduction of a multitude of local-anesthesia drugs. Perhaps the most widely known is lidocaine, which, in addition to numbing nerves, stabilizes the heart from erratic beats. Research on new medications has slowed to a crawl, however; the last significant drug was added twenty years ago. Despite the lack of new drugs, the use of regional anesthesia is expanding, with better and easier imaging techniques making it possible to accurately place current drugs on more nerves.
AREFLEXIA IS A CONCEPT that I still struggle with, because it is like lassoing a cloud. It consists of adjusting the depth of anesthesia, controlling the patient’s blood volume, and adding drugs that alter heart rate and blood pressure, while taking into consideration the procedure and the patient’s health.
Controlling the heart rate and blood pressure of an anesthetized patient requires assessing many variables, and the relationship between the two is complex. For a sick heart, one with narrowed coronary arteries, slowing
the heart rate is beneficial because it lessens the work of the heart and improves blood flow to the heart muscle. The opposite is true with a burst brain aneurysm, in which case maintaining a hyperdynamic state—keeping the blood pressure high—is thought to improve brain blood flow and survival. With a young patient, a faster heart rate is the goal. Some surgeries, such as correcting curvature of the spine, are prone to extensive blood loss, which can be limited if the blood pressure is intentionally lowered independent of the heart rate.
DECONSTRUCTING ANESTHESIA FROM THE all-in-one ether-filled orb into the Five A’s expands the responsibilities of the anesthesiologist to include the preprocedure relief of anxiety and the postprocedure continued relief of pain. Then, targeting one of the individual A’s provides optimal conditions and improved outcome for more complex and delicate procedures, such as inducing akinesia to ensure an absolutely still patient as the clip is applied on a cerebral artery aneurysm. Over the course of my career, perhaps the greatest change and also my greatest stressor has been the increase in the number of critically ill patients undergoing procedures and requiring anesthesia care, with many of these procedures life threatening and many of these patients at risk for death. That cloud must be lassoed so that areflexia can be understood and precisely controlled for optimal patient outcome.
CHAPTER 4
Railroad Tracks
IN MY ANESTHESIOLOGIST DREAMS I SEE RAILROAD tracks. Two rails connected by regularly repeating ties, running perfectly straight, parallel, and unobstructed, and drifting across my view from left to right until reaching the horizon. This is the landscape of my ideal anesthesia record. The rails are the ticks and dots representing the patient’s blood pressure and heart rate as recorded during the progress of my anesthesia care, without variance. The ties represent time, with five-minute intervals the convention for recording vital signs. In the best-case scenario, these marks form parallel lines with no slope, marching horizontally across the anesthesia record. The ultimate, stable patient.
From “Your patient is ready”—the comment made at that first painless surgery in 1846 and still used today—to “I’m finished,” my goal is a period of stability, of unvarying vital signs, of something like boredom. The well-being and survival of my patients depend on stable vital signs throughout the procedure and after. A spike in blood pressure might burst a fragile blood vessel; a rise in heart rate could push a failing heart past its limitations. My objective is to finish with an anesthesia record that marks the vital signs as flat and straight across the chart—my “railroad tracks”—a plan well accomplished. This is easier to write about than to put into practice.
From the earliest anesthesia records to the present, the sheet used for logging all the relevant data has featured a grid of boxes filling the central portion of the page, providing space to record the ticks and dots of the vital signs. The space surrounding the grid lists demographic data, including the patient identifier, weight, procedure, reason for the procedure, allergies, and a description of the anesthesia technique used for the procedure, drugs included.
Fifty years after the first ever recorded surgery performed with the patient under the effects of inhaled ether, the anesthesia record was developed. In 1905, a group of physicians with a common interest in the science and art of anesthesia held their first meeting, which led to the formation of the Long Island Society of Anesthetists, an organization that expanded throughout the state of New York and then the country, eventually changing its name in 1936 to the American Society of Anesthesiologists. Before that, medical students and surgeons were the ones who administered the ether or, in some cases, especially in Europe, chloroform.
John Snow administered chloroform to Queen Victoria for painless childbirth in 1853. In the 1890s, a pair of medical students, one about to become one of the world’s early great neurosurgeons (Harvey Cushing) and the other a leader in the organization of outcome studies in medicine (E. A. Codman) astutely noticed, while providing ether to patients, that certain bad outcomes followed trends in vital signs that veered from the straight and parallel nature of the railroad tracks. Cushing administered ether to a patient who vomited and aspirated the stomach’s contents into the lungs shortly after losing consciousness, and then promptly died. “There was a sudden great gush of fluid from the patient’s mouth,” he wrote, “most of which he inhaled and he died.”
Cushing and Codman soon developed a system to record the vital signs that were measurable at the time. From the very first dot and the very first tick placed on the first anesthesia card, Cushing’s and Codman’s intent was not to record history, but rather to predict and prevent poor outcomes.
Though perhaps a bit more formalized and organized now, the grid remains split into sections with many more vital signs that, as they became measurable, gained a place in the record. The squares of the lower section provide the space to document the patient’s vital signs in relation to elapsed time. A heart rate of one hundred beats per minute, measured fifteen minutes after the start of anesthesia, would be logged as a dot at the tenth box up and three boxes to the right of the start line. But one set of vital signs is not a trend. Within any ten-minute segment, three sets of vital signs, each with five measurements—blood pressure, heart rate, respiratory rate, oxygen saturation, and end-tidal carbon dioxide (exhaled gas)—provide enough information to make clinical decisions and adjustments.
The vital signs available to measure at the time Cushing and Codman introduced anesthesia cards were limited to heart and breathing rates. Both were measures of quantity; they didn’t measure the quality of the heartbeat or the amount of air exchanged with each breath. The average body contains over sixty thousand miles of conduit, blood vessels, that carry nutrients to and waste from all the cells of our bodies. The heart beats on average 115,000 times per day, transporting ninety-two hundred gallons of blood. In a day’s time, the average person takes over twenty-three thousand breaths. But those numbers fail to tell the story or ensure health. Today, the goal of every anesthesiologist is to make sure that the heart functions well enough to propel blood throughout all the blood vessels and to carry the fuel (oxygen) that is loaded in the lungs and intended to keep the powerhouses (mitochondria) of the furthest cell from any blood vessel energized and functioning properly.
In 1901, Willem Einthoven used generated-for-consumer electricity to measure generated-by-the-heart electricity, producing the first electrocardiogram (ECG, sometimes called an EKG because it is derived from the German word Elektrokardiogramm). Two decades later, the innovation would earn him a Nobel Prize in Physiology or Medicine. In 1920, anesthesiology recognized that the flow of electricity through the heart not only provides information on rate and rhythm, but can discern a failing heart. Unfortunately, the Einthoven ECG machine, at six hundred pounds, could not easily be used for all anesthetized patients.
Monitoring the heart by electrocardiogram grew slowly in popularity, perhaps because of a lack of certain technological advances, paired with the dangerous presence of flammable anesthesia gases in most surgical situations. The routine use of ECG monitoring during surgery was finally adopted in 1960. Although the call for standardized anesthesia records began in 1923, not until 1985 did standards for monitoring, including use of the ECG, become accepted by the American Society of Anesthesiologists. Eventually, monitors for inhaled and exhaled gases were added.
RECORDING A RAILROAD TRACK anesthesia record is easy in concept but challenging in practice. Finding a status quo in vital signs requires anticipating fluctuating body stresses during the progress of a procedure and adjusting the depth of anesthesia before allowing the tracks to take on the appearance of a roller coaster streaking up and down. The stress of making incisions in the skin, Bovie-cauterizing breached blood vessels (William Bovie was a physicist and colleague of Cushing, who in 1926 developed an electric wand used to coagulate blood vessels and decrease blood loss), and cutting bone causes catecholamine surges, which result in increased heart rates and spiking blood pres
sure. These vital-sign changes, in turn, necessitate more profound anesthesia. As time passes with little stimulation, such as while waiting for an X-ray or pathology report—the downtime during a procedure that is known as a DUA (discussion under anesthesia)—the patient requires a lessened depth of anesthesia.
Whereas some surgeons are models of efficiency, others thrive on DUAs. Hand surgery is performed with the patient’s arm extended out to the side and the hand placed on a table attached to the OR table. The surgeon sits during the procedure, as at the dinner table. In the middle of a case, one particular hand surgeon I knew—despite his pokiness, a favorite of mine—would put his surgical instruments down, rest his elbows on the hand table, clasp his hands at mouth level, and dive into a full-blown DUA regaling all in the room with stories from a long and eventful career. I learned to remain very quiet while performing anesthesia on his patients, for if I spoke and prompted him to launch into a DUA, the OR staff would glare at me.
“Calm.” “Lull.” “Doldrums.” These words are my friends; they describe my goal for the “interlude,” the maintenance period of an anesthetic, the time between the induction of anesthesia and emergence. No swaying patient stresses, causing swaying vital signs as the procedure progresses. Steady anesthesia depth. My records appearing as railroad tracks.
It is the interlude that gives an anesthesiologist the opportunity to grow from competent to great. During the induction and emergence periods, all actions on the patient originate with the anesthesiologist. During the interlude, the actions on the patient turn from the anesthesiologist to the proceduralist. An anesthesiologist who sits behind the surgical drapes can only react to the changes in a patient’s vital signs that result from the procedure. But an anesthesiologist who stands can observe all that happens and learn to become proactive, monitoring the moves and competence of the proceduralist. That’s the period when I watch with care the skill of the proceduralist. If I learn to predict the surgeon’s next action and the effect on the patient, I can move to prevent unfavorable changes in my patient before they become problematic.
Counting Backwards Page 4