Limitation of Life-Sustaining Care in the Critically Ill: A Systematic Review of the Literature
When life-sustaining treatments (LST) are no longer effective or consistent with patient preferences, limitations may be set so that LSTs are withdrawn or withheld from the patient. Many studies have examined the frequency of limitations of LST in intensive care unit (ICU) settings in the past 30 years. This systematic review describes variation and patient characteristics associated with limitations of LST in critically ill patients in all types of ICUs in the United States. A comprehensive search of the literature was performed by a medical librarian between December 2014 and April 2017. A total of 1,882 unique titles and abstracts were reviewed, 113 were selected for article review, and 36 studies were fully reviewed. Patient factors associated with an increased likelihood of limiting LST included white race, older age, female sex, poor preadmission functional status, multiple comorbidities, and worse illness severity score. Based on several large, multicenter studies, there was a trend toward a higher frequency of limitation of LST over time. However, there is large variability between ICUs in the proportion of patients with limitations and on the proportion of deaths preceded by a limitation. Increases in the frequency of limitations of LST over time suggests changing attitudes about aggressive end-of-life-care. Limitations are more common for patients with worse premorbid health and greater ICU illness severity. While some differences in the frequency of limitations of LST may be explained by personal factors such as race, there is unexplained wide variability between units.
© 2019 Society of Hospital Medicine
Factors Related to Critical Illness
There were several illness severity indicators that were associated with limitations. The Acute Physiology and Chronic Health Evaluation (APACHE) scores were the most common for medical patients and Glasgow Coma Scale (GCS) was the most common for patients with neurologic injury. Eight studies reported that a higher APACHE score was associated with an increased likelihood of limitations.3,7,10,15,17,20,22,24 Similar associations were found based on the Sepsis Related Organ Failure Assessment score in one study and a scoring system developed by the author in a second study.25,26
Seven studies, consisting of three neurologic, two medical-surgical, and two trauma cohorts, reported that a lower GCS score increased the likelihood that the patient would have limited LST.5,10,11,13,14,18,22 Additionally, Geocadin and colleagues discussed the difficulty with neurological prognostication in clinical practice; they reported that the cortical evoked potential (CEP) was correlated with the time to withdrawLST if the CEP was malignant, and the time to withdraw LST was less in malignant than in benign CEP.27
Mortality and End Effects of Limiting LST
Chen and colleagues used propensity scores to control for mortality differences between patients who had full interventions versus those with limitations and found that higher mortality correlated with the decision to withhold or withdraw LST.10 Weimer and colleagues used modeling to predict the probable outcome of patients who experienced an intracranial hemorrhage who had limitation of LST. Based on this model, nearly all the patients in their study would have died or had severe disability at 12 months despite having maximal therapy; they concluded that withdrawal of LST may not have been a self-fulfilling prophecy as others have proposed.28 Mulder and colleagues reported that in a small cohort of out-of-hospital cardiac arrest survivors admitted to the hospital, over one-third had good neurological outcomes after coding after 72 hours.29 The study highlighted the importance of timing in neurological prognostication.
Variation in Limitation Rates among Centers
In the 36 studies, we found an overall range of DNR orders from 5.4%7 to 82.0%.30 For other limitations, the rates ranged from 6.3%13 to 80.4%.31 Hart reported a low rate of limitations (4.8%) at the time of ICU admission.16 Four large, multicenter studies drew attention to the large variability between critical care centers and the limitation of end-of-life care.3-5,14 Jayes first described this phenomenon when examining the frequency of DNR orders from 1979 to 1980 and 1988 to 1990.3 This study found a range from 1.5% to 22%. Later, in another large, multicenter study, Prendergast et al. looked at 131 ICUs at 110 different institutions in 38 states that participated in postgraduate training and found variability in CPR attempts prior to death between 4% and 79%.4 In 2008, Nathens et al. reported significant variation in DNR rates across trauma centers; they found a higher incidence of DNR orders when there was an open ICU structure.14
Overall, there was wide variation in the proportion of deaths preceded by limitation of LST, ranging from 29.5% in one study of trauma patients8 to 92% in another study of trauma patients whose death occurred after 24 hours of care.9 In the largest study to date by Quill and colleagues utilizing the IMPACT database, they found large variability in the number of deaths preceded by full intervention based on differences in practice patterns of critical care centers.5
