Noise-cancelling headphones prevent vomiting after surgery

Nausea and vomiting frequently occur after surgery, but a recent study suggests that noise-cancelling headphones may help prevent these side effects. According to the findings presented at the Anesthesiology conference in San Diego, patients who wore ear defenders during general anesthesia were less likely to experience vomiting and experienced less severe symptoms in the 48 hours following their operation.

The study involved 192 patients who underwent keyhole gynaecological surgery under general anesthesia. Half of the participants were randomly assigned to wear noise-blocking ear defenders for the duration of the procedure, while all patients received standard anesthesia and anti-nausea medication. The researchers found that 35% of those wearing the ear defenders experienced nausea or vomiting within 48 hours, compared to 52% of those who did not wear them.

The researchers also noted that the symptoms were less severe among the patients whose hearing was protected by the ear defenders. This finding adds to the growing body of research suggesting that our brains process sounds even when we're not consciously aware of them. The study's lead author, Huayue Liu from the First Affiliated Hospital of Soochow University in Suzhou, China, explains that the results are consistent with decades of research indicating that anesthesia is not simply an off switch.

While the relationship between sound, nausea, and vomiting, and anesthesia is not fully understood, it is believed that noise may trigger a stress response that activates the autonomic nervous system, which regulates involuntary bodily functions such as heart rate. This interaction with brainstem pathways involved in nausea and vomiting could explain why noise-cancelling headphones may be effective in preventing these side effects.

However, the study's authors did not investigate the mechanism behind how ear defenders prevent nausea and vomiting, so the idea remains a hypothesis.