Decades ago, doctors performed surgery on babies without anesthesia? They thought babies couldn't feel pain

We all know that babies cry to express physical feelings, such as hunger, fear, and of course pain. But did you know that until the 1980s, doctors generally did not actively use anesthesia when performing surgery on babies because it was considered a medical consensus at the time that "babies do not feel pain." Why is this?

How does pain come about?

In 1985, a premature baby named Jeffrey Lawson was born in the United States. The doctor found that his pulmonary artery ductus did not close naturally and decided to perform surgery immediately. This is a common developmental defect in premature babies, which will seriously affect the baby's blood circulation. This operation requires an incision in the neck to enter the chest cavity to repair the blood vessels, and it is also necessary to cooperate with the operation to pull the tissues and organs in the chest cavity. However, the doctor did not use anesthetics during the operation, only muscle relaxants. Therefore, little Jeffrey would not move during the operation, but he was always conscious. Later, little Jeffrey unfortunately died of multiple organ failure.

His mother was very surprised and heartbroken when she learned that no anesthetics were used during the operation. But in that era, "babies have no sense of pain" could be considered a medical consensus. Babies, especially fragile premature babies, are more sensitive to drugs and have higher risks than adults. Anesthetics that act on the nervous system are a type of drug that requires strict supervision. Based on these perceptions, doctors generally do not actively use anesthetics when performing surgery on babies.

Why did people think that babies had no sense of pain? First, let us understand what pain is.

The International Association for the Study of Pain defines pain as "an unpleasant sensory and emotional experience associated with tissue damage or potential damage". The most common is superficial pain from the skin, which is usually sharp, localized, and has a clear location; while visceral pain deep in the body is more of a dull pain, can be chronic, and may not be clearly located. For example, some patients with myocardial infarction feel obvious back pain instead of chest pain.

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The human body's skin, tissues and organs are rich in nerve endings, which convert harmful stimuli into electrical signals, transmit them to the brainstem and thalamus through the spinal cord, and ultimately produce a feeling of pain in the cerebral cortex.

Babies’ pain perception was once ignored

Before the 19th century, people's understanding of pain was not comprehensive enough. In addition, infants are a vulnerable group and cannot fully express their feelings, so their perceptual abilities, including pain, were generally ignored and denied.

In 1859, more than a decade after the advent of anesthesia, Charles Darwin published his famous book, The Origin of Species. The theories in it contributed to a naive view that humans evolved from lower life forms. Some people see newborns as a state of life close to the early stages of human evolution, more like ignorant little animals than humans.

In addition, unlike blood pressure, heart rate and other indicators that can be directly measured, the main information about pain depends more on the patient's verbal description. People who have seen a doctor will remember that the doctor will ask you to describe the location and nature of the pain, and may also ask you to rate the degree of pain from 1 to 10. Obviously, babies cannot provide this information.

In fact, Darwin himself believed that infants felt pain, but he thought that infants were more likely to forget pain than adults. Although this view is somewhat controversial, it has prompted people to actively study the truth about infant pain.

At that time, many people believed that babies' brains were immature and they had no sense of pain. Some people conducted acupuncture experiments on babies and found that they would shed tears, but at that time it was considered a simple reflex and had nothing to do with pain.

With the development of modern science and technology, many studies have confirmed that infants are born with the ability to sense pain. In the human fetal period, the brain and spinal cord have already formed myelin sheaths of noxious nerve bundles. Substance P and its receptors can be detected in the fetal spinal cord. This is a chemical signal substance secreted by neurons that can regulate pain when the body is stimulated, such as injury or inflammation. This shows that the human nervous system for perceiving pain has been formed and has function since the fetal period.

However, there are still some differences between the neurophysiological mechanisms of infant pain and those of adults. Magnetic resonance imaging has found that after acute injuries, the amygdala and orbitofrontal cortex in the brain involved in emotion interpretation are not activated in newborns, so they may not be able to experience all the emotions of adults. In addition, infants' inhibitory function to stimuli is immature and their ability to regulate pain is weak. Data show that the pain tolerance of newborns is 30-50% lower than that of children, which means that they feel more pain for the same stimulus, and even some harmless touch and skin stimulation can cause pain in infants.

A scientific look at infant pain

Pain has both advantages and disadvantages. On the one hand, pain can warn the body of possible damage so that it can be avoided; on the other hand, unmanaged pain can have negative effects. Infants who are not anesthetized will have more severe stress reactions after surgery, take longer to recover after surgery, and are more likely to have postoperative complications. Early pain experiences may lead to abnormal development of the infant's stress response system or reduce the child's ability to self-regulate after experiencing painful events. Some infants' bad tempers when they are toddlers may be closely related to this. Pain can also make infants feel distrustful and fearful of their caregivers. The infant period from 0 to 3 years old is the period of the fastest physical and psychological development of individuals, so pain management for infants is becoming increasingly important.

In 1987, the American Society of Anesthesiologists and the American Academy of Pediatrics announced that it was no longer ethical to perform surgery on infants without anesthesia. Since infants cannot speak, researchers have developed tools in multiple dimensions to monitor their pain. For example, from physiological indicators such as blood pressure, heart rate, and blood oxygen saturation, or from behavioral indicators such as crying, facial expressions, muscle tension, and sleep conditions. In recent years, neuroimaging technologies such as electroencephalography, near-infrared imaging, and functional magnetic resonance imaging have also been increasingly used in clinical evaluations, providing important data on brain electrophysiology, hemodynamics, and other aspects for further research on infant pain.

Infant pain perception is an issue that has received much attention. As technology continues to advance, our knowledge and understanding of infant pain will continue to improve.

This article is a work supported by Science Popularization China Starry Sky Project

Author: Xu Sijia

Reviewer: Tao Ning (Associate Researcher, Institute of Biophysics, Chinese Academy of Sciences)

Produced by: China Association for Science and Technology Department of Science Popularization

Producer: China Science and Technology Press Co., Ltd., Beijing Zhongke Xinghe Culture Media Co., Ltd.