Contrary to previous beliefs, researchers have found that Nitrous oxide (laughing gas) doesn't increase a person's risk of heart attack.
Nitrogen Oxide (laughing gas) is one of the most commonly used anesthetics. However, in previous studies, researchers have argued about its impact on the chances of heart attacks. Now, a new study conducted by researchers from Washington University in St. Louis confirms that nitrogen oxide doesn't increase the risk of heart attacks.
"It's been known for quite a while that laughing gas inactivates vitamin B12 and, by doing so, increases blood levels of the amino acid homocysteine," said lead author Peter Nagele, MD, assistant professor of anesthesiology and genetics in a press statement. "That was thought to raise the risk of a heart attack during and after surgery, but we found no evidence of that in this study."
Nitrogen oxide in itself is not capable of keeping a person fully unconscious during a surgery and hence, is often used as an adjunct during general anesthesia. Though the compound is known to have an effect on Vitamin B and homocysteine, this has nothing to do with its anesthetic characteristics.
For the study, the authors looked at 500 patients that had been diagnosed with health problems that were known to cause heart attacks like coronary artery disease and heart failure. They had all undergone noncardiac surgery and received nitrous oxide anesthesia. The patients in the study were divided into two groups. The first group received intravenous vitamin B12 and folic acid to help prevent homocysteine levels from rising during surgery while the other group did not get the intravenous B vitamins.
"There were no differences between the groups with regard to heart attack risk," Nagele said. "The B vitamins kept homocysteine levels from rising, but that didn't influence heart attack risk."
For 72 hours that followed, researchers also monitored cardiac troponin I, a marker of heart damage to detect any heart attacks during and after surgery. A rise in troponin levels indicates damage to the heart. Researchers observed no such rise in troponin levels. They also analyzed whether genes played any role in the rise of homocysteine in a person and found that people with common variants in the MTHFR gene generally produce high levels of homocysteine in the body. If such people are given nitrous oxide anesthesia, this level can rise even higher.
Researchers found that only 3.1 percent of patients with common variants in the MTHFR gene experienced a heart attack during surgery compared to the 4.4 percent of patients without the gene variant who experienced a heart attack during surgery
