Press Release

May 2008

Haunted by Hallucinations: Children in the PICU Traumatized by Delusions

Nearly one in three children admitted to pediatric intensive care will experience delusions or hallucinations, which put them at higher risk for post-traumatic stress symptoms, according to a new study of children’s experiences in a pediatric intensive care unit (PICU).

The study, which appears in the first issue for May of the American Journal of Respiratory and Critical Care Medicine, published by the American Thoracic Society, is believed to be the largest ever conducted on children’s memories of PICU.

The results confirmed the clinical experience of the study’s first author, Gillian Colville, B.Sc., M.Phil., a clinical psychologist, and underscore the need to look at this issue more closely. “I have worked for 16 years in pediatric intensive care and have seen a considerable number of children in distress, but have found that there is very little in the literature about children’s experiences,” said Ms. Colville.

To determine whether she was witnessing a unique population of children, or if hallucinations and delusional memories were an overlooked but common experience for children in the PICU, Ms. Colville and her collaborators recruited children over the age of seven who were discharged from the 21-bed PICU at Great Ormond Street Children’s Hospital in London, over the course of 18 months. Each child’s medical condition and treatment was noted and they were given a psychological interview three months after discharge to screen them for post-traumatic stress symptoms in relation to their memories.  

Of the 102 children who completed interviews, two in three recalled something factual about their stay at the PICU— and half of these had only fragmentary, single memories, mostly images of family members. But one in three children reported delusional memories of their stay in PICU, including hallucinations. It was these children who reported delusional memories that had a significantly higher score on the post-traumatic stress screening test than others.

“These findings are interesting because it has been assumed that the actual experiences in the PICU would be more likely to lead to post-traumatic stress symptoms following discharge,” said Ms. Colville. “However, our results indicate that post-traumatic stress symptoms are associated with delusional memories rather than factual ones. The hallucinations children reported were overwhelmingly disturbing and frightening, similar to those reported by adult intensive care patients and heroin addicts going through withdrawal.”   

The findings have important clinical implications, as the timing of the hallucinations appeared to coincide with the period during which they were being weaned off the sedatives commonly prescribed on PICU (benzodiazepines and opiates) and children were five times as likely to report having had delusions or hallucinations if they had been prescribed opiates and benzodiazepines for more than two days.

The authors do not suggest that the drugs be discontinued, but that they do warrant further study. Additional research could establish whether alternative types of sedation or the introduction of drug holidays might produce fewer traumatic delusional memories. The authors also suggest altering the physical environment and providing psychological orientation cues for children in the PICU, such as demarcating day and night, to help reduce these symptoms.  

“But above all, medical professionals and families should be made aware of the possibility that children may have these disturbing hallucinatory experiences, and greater efforts should be made to monitor their psychological adjustment after PICU,” said Ms. Colville.  

Contact for Study: Gillian Colville, Pediatric Psychology Service, St. George’s Hospital, London SW17 0QT, UK
Phone: +44-208-725-2214
E-mail: gcolvill@sgul.ac.uk

Obesity Worsens Impact of Asthma

Obesity can worsen the impact of asthma and may also mask its severity in standard tests, according to researchers in New Zealand, who studied lung function in asthmatic women with a range of body mass indexes (BMIs).

This is the first prospective study to reveal a significant comparative difference in how the airways and lungs respond to a simulated asthma attack in obese and non-obese individuals.

The research is reported in the first issue for May of the American Journal of Respiratory and Critical Care Medicine, published by the American Thoracic Society. It establishes a direct link between obesity and the development of a phenomenon known as “dynamic hyperinflation”—when air breathed into the lungs cannot be exhaled. This often occurs with acute asthma, but is more frequent in obese individuals.  

“We have demonstrated significant differences in the changes in respiratory function that occur with asthmatic bronchoconstriction in relation to obesity,” said principal investigator, D. Robin Taylor, M.D., of the University of Otago in New Zealand.

The researchers recruited 30 asthmatic women and divided them into three groups by BMI: normal weight, overweight and obese. Each woman breathed nebulized methacholine to artificially induce an asthma-like attack, and was then assessed for changes in lung function on several measures, including how much air remained in her lungs after exhalation (functional residual capacity, or FRC) and how much air she could breathe in on her next breath (inspiratory capacity, or IC).

“After the methacholine challenge, the amount of bronchoconstriction was identical for each of the three groups, but the changes in FRC and IC were greatest in the obese group. This indicated to us that greater dynamic hyperinflation was occurring among obese individuals,” said Dr. Taylor.

With increasing BMI, FRC was higher, whereas IC was significantly decreased. “This means that among women with greater BMI, an asthma-like episode has the potential to cause greater breathing difficulties than in non-obese women,” said Dr. Taylor. “The greater dynamic hyperinflation means that obese individuals lose the ability to inhale as deeply or exhale as fully as normal weight individuals.”

Curiously, the group of obese individuals with asthma differed from their non-asthmatic counterparts in having alower FRC before the methacholine challenge than the non-obese group, yet still recorded a greater increase in FRC after the methacholine challenge. “This is the surprising finding in our study. It is quite counterintuitive. You would expect individuals with a heavier chest wall not to develop hyperinflation quite so readily as those who are lighter. But that is not what happened,” said Dr. Taylor.

Perhaps most importantly, these findings point to fundamental differences in the way that obese individuals might experience shortness of breath if they have asthma. “We know that asthma in obese subjects is more likely to persist and is more likely to be perceived to be severe. These individuals often require more treatment to achieve asthma control. Our study provides an insight into why this might be happening–the same asthma “trigger” produces a greater effect in obese individuals.”

The study also showed that simple spirometry was inadequate to determine the level of pulmonary dysfunction which was occurring in obese individuals.

“Our findings need to be explored further. We need to confirm that the differences in dynamic hyperinflation between obese and non-obese asthmatics are sufficient to explain the differences in symptoms between the two groups. Our study was not large enough to do this,” said Dr. Taylor.

Contact for Study: D. Robin Taylor, M.D., Otago Respiratory Reserarch Unit, Dunedin School of Medicine, University of Otago, P.O. Box 913, Dunedin, NZ
Phone: +64-03-47- 0999
E-mail: robin.taylor@stonebow.otago.ac.nz

Green Tea Compounds Beat OSA-Related Brain Deficits

Chemicals found in green tea may be able to stave off the cognitive deficits that occur with obstructive sleep apnea (OSA), according to a new study published in the second issue for May of the American Thoracic Society’s American Journal of Respiratory and Critical Care Medicine.

Researchers examined the effects green tea polyphenols (GTP), administered through drinking water, on rats who were intermittently deprived of oxygen during 12-hour “night” cycles, mimicking the intermittent hypoxia (IH) that humans with OSA experience. 

People with OSA have been reported to have increased markers of oxidative stress and exhibit architectural changes in their brain tissue in areas involved in learning and memory. Chronic IH in rats produce similar neurological deficit patterns.

“OSA has been increasingly recognized as a serious and frequent health condition with potential long-term morbidities that include learning and psychological disabilities […],” wrote David Gozal, M.D., professor and director of Kosair Children’s Hospital Research Institute at the University of Louisville, lead author of the article. “A growing body of evidence suggests that the adverse neurobehavioral consequences imposed by IH stem, at least in part, from oxidative stress and inflammatory signaling cascades.”

GTPs are known to possess anti-oxidant properties, acting as a free radical scavengers, and research has shown that the compounds may reduce the risk of a variety of different diseases.

“Recent studies have demonstrated the neuroprotective activity of GTP in animal models of neurodegenerative conditions such as Parkinson’s and Alzheimer’s disease,” wrote Dr. Gozal.

In this study, the researchers divided 106 male rats into two groups that underwent intermittent oxygen depletion during the 12-hour “night” cycle for 14 days. One group received drinking water treated with GTP; the other received plain drinking water. 

They were then tested for markers of inflammation and oxidative stress, as well as for performance in spatial learning and memory tasks—namely a water “maze” in which the rat had to memorize the location of a hidden platform. 

The IH-rats that received the green tea-treated water performed significantly better in a water maze than the rats that drank plain water. “GTP-treated rats exposed to IH displayed significantly greater spatial bias for the previous hidden platform position, indicating that GTPs are capable of attenuating IH-induced spatial learning deficits,” wrote Dr. Gozal, adding that GTPs “may represent a potential interventional strategy for patients” with sleep-disordered breathing.

Contact for study: David Gozal, M.D., Kosair Children’s Hospital Research Institute, University of Louisville, 570 South Pearson St., Suite 204, Louisville, KY
Phone:(502) 852-2323 or (502) 299-1125
E-mail: david.gozal@louisville.edu

These news briefs are based on articles published in the American Thoracic Society's peer-reviewed journal, the American Journal of Respiratory and Critical Care Medicine. In reporting on these findings, contact information is for your use only, not for publication. Journalists may obtain the full text of these articles, request a complimentary subscription to the journal, or identify an expert not related to the research to comment on the article by contacting Keely Savoie at ksavoie@thoracic.org or (212) 315-8620 or Brian Kell, Director of Communications, at (212) 315-6442 or bkell@thoracic.org.

Founded in 1905, the American Thoracic Society is the world’s leading medical association dedicated to advancing pulmonary, critical care and sleep medicine. The Society has more than 18,000 members who prevent and fight respiratory disease around the globe, through research, education, patient care and advocacy.