Critically ill smokers risk death by continuing to use nicotine-replacement therapy (NRT) while they are in hospital intensive-care units (ICUs), HealthDay News reported Oct. 25.

The death rate of NRT users in ICUs was 21.4 percent, compared to 5.4 percent among a control group, according to a study from the Mayo Clinic College of Medicine.

"In some critically ill patients, the development of nicotine-withdrawal symptoms can worsen their prognosis. As a result, NRT is given to active smokers in the ICU," lead researcher Amy Lee explained. "The hemodynamic effects of nicotine may lead to increased heart rate, systemic arterial blood pressure, and constriction of the coronary arteries. Although these potential adverse effects of NRT have not been shown to worsen the prognosis of healthy volunteers and patients with stable coronary artery disease, they may be detrimental to critically ill patients."

The research was presented at the American College of Chest Physicians annual meeting.