In the darkness, Karen Bryer could see a tiny dot of light shining from a distant corner. She heard someone call her name sharply.
As the light got closer, the stranger’s voice grew more demanding. She sensed she was in grave danger. The light was becoming unbearably bright. Unseen hands groped her face. Bryer then felt herself being picked up by her ankles and spun around until she was dizzy and nauseous. She wanted to die.
In a state of delirium, while waking up in a hospital bed, Bryer experienced these hallucinations – and her terror – vividly.
“It was very, very real. It was actually happening. There was nothing that could convince me that it was a dream,” says the Toronto resident, who experienced multiple such episodes of delirium while in hospital with a rare heart disease, called giant cell myocarditis, in 2014.
It wasn’t until after Bryer received a heart transplant and her condition improved that she realized the light she had seen was likely from a nurse checking her pupils, while calling Bryer’s name to determine whether she was regaining consciousness.
Once considered a normal occurrence among critically ill patients, delirium is a serious condition that researchers and health professionals are seeking new and better ways to prevent. They are now understanding how frequently, and how profoundly, it can affect patients.
“Delirium is like brain failure … so you’re not able to cope with a situation because of various [injuries or traumas]‚” says Dr. Marcel Émond, clinician scientist and professor at Université Laval. He explains those injuries or traumas can be either from the patient’s disease or from something that happens during their care, such as a disruption of their sleep in the hospital environment, a lack of windows to help them stay oriented to the time of day, or the use of catheters that restrict their ability to move. Health professionals now recognize “we have to make sure we’re giving our full attention to prevent this," he says.
In intensive care units, various studies have estimated anywhere from 30 per cent to more than 80 per cent of patients experience it. Meanwhile, a study led by Émond and published earlier this year found one in eight older patients, who were independent or semi-independent, developed delirium after spending eight hours in Canadian hospital emergency departments. That number is expected to surge as the population of older adults, who are at higher risk, grows.
Delirium, characterized by confusion, hallucinations and agitation or unresponsiveness, typically lasts only a few days or weeks, but it can have a serious impact. Patients who have it tend to be at greater risk of lengthier hospital stays, long-term brain dysfunction, and even death.
The specific causes are yet unknown. But researchers in Kingston, are starting a multicentre study to determine whether low oxygen supply to the brain may be a contributing factor. If they’re successful, their work could add to a short but growing list of strategies to address this complex and confounding condition.
“I think it’s similar to stroke, where a lack of blood and oxygen delivery to the brain causes neural damage,” says Dr. Gordon Boyd, a clinician scientist at Kingston General Hospital, who is the principal investigator of the study.
Boyd explains he and his colleagues plan to study 500 patients at hospitals in Ontario, Quebec and B.C., who are either on life support on a ventilator or on medication to support their blood pressure. The researchers will use technology, called near infrared spectroscopy, which, he describes, is a sensor placed on the patient’s forehead to measure how much oxygen is being delivered to their brain. The team then intends to correlate these measurements with the patients’ risk of developing delirium and long-term cognitive impairment.
If they find low oxygen delivery to the brain is, indeed, a risk factor, doctors can then use near infrared spectroscopy to guide them in preventing delirium.
“Whether [patients] come in with pneumonia … or a ruptured aneurysm in their abdomen, we can put these sensors on their foreheads, and then target cerebral oxygen delivery during their critical illness to try to reduce the risk of developing delirium and improve their long-term cognitive outcome,” he says.
In Montreal, Dr. Yoanna Skrobik, a pioneer in delirium research who began studying delirium in intensive care units two decades ago, says if the Kingston-led researchers are successful, they’ll have identified a clearer marker for delirium than anything found so far. But she’s not holding her breath. As she has learned over the years, the complexities of delirium are difficult to untangle.
Skrobik, who is a professor of medicine at the University of Montreal and McGill University, explains there is no effective treatment for delirium, but studies show that measures, such as getting patients out of bed and mobilized, and making sure they sleep, can help reduce the incidence.
Earlier this year, Skrobik and her team published a study that showed when patients in intensive care were given a low-dose sedative, called dexmedetomidine, at night, the incidence of delirium was reduced dramatically. While she says she isn’t sure whether this was because patients on the medication slept better her study offers the first pharmacological protocol for preventing delirium.
Skrobik emphasizes that while they may be at higher risk, not everyone who has delirium will have long-term negative outcomes. An important lesson she’s learned over the years is that patients who are experiencing hallucinations and confusion need reassurance – they need to be told that what they’re going through is delirium, that it’s part of critical illness, and that they can get better.
“That is as much part of their healing as any medication you can give them, or any technique you can throw at them,” she says.
Screening patients for delirium is very important, she says, not because doctors are yet able to treat them, but because it can be terrifying for patients, and patients with delirium may think their caregivers and health-care providers are out to harm them.
“If you can reassure them, if you can soften that fear, then I think we’ve done our homework,” she says.