Mixing Muscle Relaxants and Anesthetics Raises Respiratory Risk

A new study concludes that administering neuromuscular blocking drugs during general anesthesia (GA) is associated with an increased risk of postoperative pulmonary complications.

Researchers at Munich Technical University (TUM; Germany), Karolinska Institutet (KI; Solna, Sweden), the University of Liverpool (United Kingdom), and other institutions conducted a multicenter observational study to assess if neuromuscular blocking agent use is associated with postoperative pulmonary complications. To do so, they collected data from 22,803 patients who received anesthesia for any in-hospital procedure--except cardiac surgery--conducted in 211 hospitals in 28 European countries over the course of a year.

Patient characteristics, surgical and anesthetic details, and chart review at discharge were prospectively collected over two weeks. Each patient also had a postoperative physical examination within three days of surgery for adverse pulmonary events. Overall, about three quarters of all patients (17,150 people) were treated with neuromuscular blocking agents. The most common respiratory complications were a transient reduced lung capacity for oxygen absorption (5.2%), and infections of the lung and respiratory tract (2.5%).

The results showed that patients receiving neuromuscular blocking agents while under GA had a significantly higher (4.4%) risk of developing any type of respiratory complication. The study also showed that neither neuromuscular monitoring, nor the administration of reversal agents reduced the risk. The researchers are now planning to implement more targeted studies in order to identify the underlying mechanisms behind their findings. The study was published on September 14, 2018, in Lancet Respiratory Medicine.

“Neuromuscular blocking agents have made surgery considerably safer and more effective since their introduction. These drugs are particularly needed when operating on a patient's chest or abdomen. They are also used to protect the vocal cords from injury when a tube is placed in the airway to allow artificial ventilation,” said senior author Professor Manfred Blobner, MD, of TUM. “Patients undergoing minor surgical procedures that do not necessarily require neuromuscular blocking drugs might benefit from avoiding them. Using devices like laryngeal masks for anesthesia instead of tracheal tubes that go past the vocal cords could prove helpful as well.”

Related Links:
Munich Technical University
Karolinska Institutet
University of Liverpool