Long-term outcomes of post-cardiac arrest patients with severe neurological and functional impairments at hospital discharge

Abstract

Background:

Patients resuscitated from cardiac arrest who have severe neurological or functional disability at discharge require high-intensity long-term support. However, few data describe the long-term survival and health-care utilization for these patients.

Methods:

We identified a cohort of cardiac arrest survivors ≥ 18 years of age, treated at a single center in Western Pennsylvania from January 2010 to December 2019, with a modified Rankin scale (mRS) of 5 at hospital discharge. We recorded demographics, cardiac arrest characteristics, and neurological exam at hospital discharge. We characterized long term survival and mortality through December 31, 2020 through National Death Index query. We described survival time overall and in subgroups using Kaplan-Meier curves and compared using log-rank tests. We linked cases with administrative data to determine 30, 90 day, and one-year hospital readmission rate. For subjects unable to follow commands at discharge, we reviewed records from index hospitalization to the present to describe improvement in neurological status and return home.

Results:

We screened 2,687 patients of which 975 survived to discharge. We identified 190 subjects with mRS of 5 at hospital discharge who were sent to non-hospice settings. Of these, 43 (23%) did not follow commands at discharge. One-year mortality was 38% (n = 71) with a median survival time of 4.2 years (IQR 0.3–10.9). Duration of survival was shorter in older subjects but did not differ based on, sex, or ability to follow commands at hospital discharge. Within the first year of discharge, 58% (n = 111) of subjects had at least one hospitalization with a median length of stay of 8 days [IQR 3–19]. Of subjects who did not follow commands at hospital discharge, 5/43 (11%) followed commands and 9 (21%) were reportedly living at home on subsequent encounters.

Conclusions:

Of survivors treated over a decade at our institution, 20% (n = 190) were discharged from the hospital with severe functional disability. One-year mortality was 38%, and hospital readmissions were frequent. Few patients discharged unable to follow commands regained the ability over the period of observation, but many did return to living at home. These data can help inform decision maker expectations for patient trajectory and life expectancy.

Introduction

Cardiac arrest is common, with a total of 650,000 Americans suffering in-hospital or out-of-hospital cardiac arrest each year.¹ Hypoxia and ischemia sustained by the brain during arrest causes an injury cascade that may include excitotoxicity, disrupted calcium homeostasis, free radical formation, and pathological protease pathways, which are associated with cell death and neurological dysfunction.^2,3 A majority of patients who are resuscitated after cardiac arrest and survive intensive care have some neurological impairments that can range from mild cognitive deficits to coma.⁴ In many cases, decision makers may withdraw life-sustaining treatment (WLST) when neurological prognosis is perceived as poor or when return to a functional capacity acceptable to the patient seems unlikely.⁵ It is critically important that decisions about WLST should be informed by reliable data about the usual clinical course for patients who are functionally dependent or who have disorders of consciousness (DoC) near the completion of acute hospitalization.

Many data concerning the long-term course of patients who survive CA with a high degree of functional dependence or DoC come from highly specialized rehabilitation settings.^6,7 In these programs, neurological and functional improvement are possible, and referral of DoC patients to these settings is recommended.⁸ However, data from rehabilitation settings may select for patients with higher probability of recovery, and reported outcomes may be better than in unselected DoC or high functional dependency patients.⁷ Many of these patients after acute hospitalization go to skilled nursing or long term care facilities, where outcomes are poorly described.

In this study, we describe the long-term survival and hospital readmissions of post cardiac arrest patients with severe functional dependence at the end of their acute care hospitalization for whom families and care teams did not choose WLST. We hypothesized that most of these patients would survive for less than one year, that hospital readmission would be frequent, and that few patients that were unable to follow commands at hospital discharge would regain communication or return home.

Methods

We conducted a retrospective, single-center cohort study of cardiac arrest patients treated at a regional referral center for post-cardiac arrest care in Western Pennsylvania. The University of Pittsburgh Human Research Protection Office deemed this to be minimal risk research and exempt from the requirement of informed consent. We included both in-hospital and out-of-hospital cardiac arrest survivors who were ≥18 years of age, who were hospitalized between January 2010 and December 2019, and had a modified Rankin scale (mRS) of 5 at hospital discharge.

Patients were identified from a prospective quality improvement and research database for our institution, which includes all identified cardiac arrest patients in our hospital during the observation period.^9,10 Within the study center, our Post Cardiac Arrest Service (PCAS) is consulted in the Emergency Department and Intensive Care Units for workup of underlying etiology, consideration of cardiac catheterization, neurological resuscitation, targeted temperature management (TTM), prognostic testing, goals of care discussions, and in survivors, neurocognitive testing and coordination of neurological rehabilitation evaluations. All patients in this cohort were evaluated by this service. We utilized multimodal prognostic testing to guide prognostic workup and held regular quality assurance meetings with case review during the decade when these patients were treated. As an integrated component of the service line, cases are discussed with Physical Medicine and Rehabilitation who are formally consulted when patients are deemed to have brain injury specific or other rehabilitation needs. Discharge planning and disposition is coordinated by case management, with input from the primary medical or surgical service, consultants, physical, speech, and occupational therapy. In addition to these services, disposition is influenced by other factors including degree of medical complexity, bed availability, family preference of location, and insurance. We determined mRS specifically for the database using standardized instruments by abstractors with experience reviewing the entirety of the record.¹¹

We abstracted demographics, arrest characteristics, arrest etiology categorized as cardiac, respiratory, toxicological, unknown or other,⁹ initial illness severity using the Pittsburgh Cardiac Arrest Category (PCAC),^4,12 percutaneous or surgical feeding tube placement, tracheostomy placement, discharge disposition, and neurological exam at time of hospital discharge for all patients. Several of our local rehabilitation centers accept patients who require enteral access with flexible nasogastric tubes, which had become preferred to percutaneous or surgical feeding tube placement during the study period. We only documented feeding tubes or tracheostomy placed prior to discharge from the index hospitalization.

We determined survival by linking patient information with the National Death Index (NDI) through to December 31 2020 as previously described.¹³ We chose this date as the end point of observation to allow at least one year of potential observation time for each subject. We identified all-cause hospital readmissions to any one of the 42 hospitals across Western Pennsylvania and neighboring portions of Ohio, New York, West Virginia and Maryland within the University of Pittsburgh Medical Center (UPMC) network within 30 days, 90 days, and one year of index hospitalization discharge through administrative query.

While only severely disable (mRS 5) patients were included, some patients were able to follow commands, whereas others were still unresponsive at hospital discharge. For subjects unable to follow commands at discharge, we recorded details of neurological prognostic testing. Specifically, we recorded initial EEG pattern, brain computed tomography (CT) findings, somatosensory evoked potentials (SSEPs), and brain magnetic resonance imaging (MRI) findings. We defined malignant neurological prognostic features as burst suppression with identical bursts (BSIB) on EEG, somatosensory evoked potentials (SSEP) with absent N20 cortical response, and cerebral edema defined as a ratio of x-ray attenuation (Hounsfeld units) in grey matter to white matter less than or equal to 1.2 on initial brain CT.^14,15 We reviewed the clinical neuroradiology interpretation of the brain MRI and noted the presence of diffusion restriction in cortex (no diffusion restriction, 1–2 lobes, ≥ 3 lobes) and midbrain (present or absent).

Our local electronic medical record allows for review of medical records from the entire UPMC hospital system as well as outpatient encounters at any of the 800 healthcare offices and outpatient clinics within the network. This health system has a catchment area of 5.7 million people, with approximately 900,000 emergency department encounters and 355,000 inpatient and observation admissions annually.¹⁶ Additionally, the health system participates in the Clinical Connect Health Information Exchange, a clinical record sharing system that allows for review of medical inpatient, outpatient, and emergency encounters across health systems in Western Pennsylvania.¹⁷ An author reviewed clinical notes and documentation for each subsequent encounter to specifically assess neurological examination, and whether or not the patient was reported to follow commands. Patient living situation was recorded at the time of hospital discharge and for each subsequent healthcare encounter. We identified patients that were reported as living at home at any encounter.

We describe the features and subsequent events for included patients considering separately those who did and did not follow commands. We also report separately those who were discharged from the hospital to hospice. We used mean and standard deviation (SD) to describe continuous variables with normal distribution. We used medians, counts, proportions, and interquartile ranges (IQR) to describe categorical or ordinal variables and variables with non-normal distributions. We did not conduct a formal power calculation because this study is descriptive, and we used all available cases. Our primary outcome was the duration of survival from index hospitalization. Survival time was described using Kaplan-Meier curves. We considered date of index cardiac arrest hospital discharge as time zero of observation. We performed log-rank tests to compare mortality between subgroups of interest including age ≥ 65, female sex, follow vs. not follow commands at hospital discharge and presence of malignant neurological prognostic testing. As secondary outcomes, we describe the frequency and duration of readmission after hospital discharge. We also report the proportion and characteristics of patients unable to follow commands at index hospitalization discharge, who were noted to be following commands at subsequent encounters. We evaluated if any malignant neurological findings were present in these subjects. We report the number of patients discharged unable to follow commands who were ultimately living at home instead of at an institutional facility on subsequent encounters.

Results

Among 2,687 cardiac arrest patients treated during the study period, 234 had mRS of 5 at hospital discharge (Fig. 1; characteristics of excluded patients- Supplemental Table 1). Forty-seven of these patients were discharged from the acute care hospital to hospice, which more than half were unable to follow commands (n = 25, 67%). Among 47 subjects discharged to hospice after acute hospitalization, one-year mortality was 89% (n = 42) with a median survival time of 4 days [IQR 2–17].

Fig. 1 –

Study inclusion.

Among the remaining 190 subjects who were discharged to acute rehabilitation, skilled nursing, and long-term acute care facilities, 43 (23%) had a were unable to follow commands at hospital discharge. Median age was 62 [Interquartile Range (IQR) 50–71], 74 (39%) were female, and 113 (59%) collapsed outside of the hospital (Table 1). Median length of hospital stay was 21 days [IQR 15–33]. We report the characteristics of patients that had WLST for poor neurological prognosis listed in Table 1 for comparison. Of patients that had WLST prior to discharge, 70% (n = 499) had at least one malignant prognostic test result (cerebral edema: n = 154, 22%; BSIB: n = 317, 44%; absent n20 response: n = 184, 26%).

Table 1–

Characteristics of subjects discharged to non-hospice settings.

Characteristic	Total cohort n = 190	Followed commands at discharge n = 147	Did not follow commands at discharge n = 43	WLST prior to discharge n = 714
Age, years	62 [50–71]	63 [51–71]	59 [46–71]	61 [50–71]
Female sex	74 (39%)	58 (39%)	16 (37%)	275 (38%)
Out-of-hospital cardiac arrest	113 (59%)	78 (53%)	35 (81%)	619 (87%)
Initial rhythm
VT/VF	60 (31%)	48 (33%)	12 (28%)	141 (20%)
PEA	80 (42%)	67 (45%)	13 (30%)	259 (26%)
Asystole	41 (22%)	26 (18%)	15 35%)	266 (37%)
Unknown	9 (5%)	6 (4%)	3 (7%)	48 (7%)
Witnessed status for out-of-hospital cardiac arrests
Bystander witnessed	47 (41%)	25 (32%)	22 (63%)	316 (51%)
EMS witnessed	19 (17%)	14 (18%)	5 (14%)	85 (14%)
Unwitnessed	19 (17%)	13 (17%)	6 (17%)	180 (29%)
Arrest in emergency department	28 (25%)	26 (33%)	2 (6%)	38 (6%)
CPR duration	10 [5–18]	9 [4–17]	15 [9–28]	22 [14–33]
Epinephrine doses (mg)	2 [1–3]	2 [1–3]	2 [1–4]	3 [2–5]
Pittsburgh Cardiac Arrest Category
I	57 (30%)	56 (38%)	1 (2%)	2 (1%)
II	53 (28%)	41 (28%)	12 (28%)	90 (13%)
III	21 (11%)	13 (9%)	8 (19%)	50 (7%)
IV	25 (13%)	15 (10%)	10 (23%)	511 (71%)
Unknown	34 (18%)	22 (15%)	12 (28%)	61 (8%)
Arrest etiology
Cardiac	41 (21%)	33 (22%)	8 (19%)	146 (20%)
Respiratory	41 (21%	35 (24%)	6 (14%	134 (19%
Toxicological	15 (8%)	8 (5%)	7 (16%)	76 (11%)
Unknown	37 (19%)	25 (17%)	12 (28%)	214 (30%)
Other	56 (31%)	46 (32%)	10 (39%)	144 (20%)
Length of hospital stay, days	21 [15–33]	20 [14–31]	25 [18–44]	3 [2–5]
Tracheostomy	120 (63%)	77 (52%)	43 (100%)	-
Prior tracheostomy	3 (2%)	3 (2%)	0 (0%)	-
Percutaneous or surgical feeding tube	61 (32%)	32 (22%)	29 (67%)	-
Prior percutaneous or surgical feeding tube	9(5%)	8 (5%)	1 (2%)	-
Motor exam at hospital discharge				-
Follows commands		147 (100%)	-	-
Localizing to pain			15 (35%)	-
Flexion to pain			3 (7%)	-
Extension to pain			3 (7%)	-
No response to pain			16 (37%)	-
Unable to determine			6 (14%)	-
Disposition from acute care hospital
Home	7 (4%)	7 (5%)	0 (0%)	-
Acute inpatient rehab	53 (28%)	48 (32%)	5 (12%)	-
Skilled nursing facility	64 (34%)	47 (32%)	17 (40%)	-
Long-term acute care	59 (31%)	39 (27%)	20 (46%)	-
Other inpatient hospital	7 (3%)	6 (4%)	1 (2%)	-

Data are presented as median [interquartile range] or number (percentage).

WLST- withdrawal of life sustaining therapies due to perceived poor neurological prognosis.

One subject died on the same day as hospital discharge and one subject could not be linked with NDI data, leaving 188 subjects with non-hospice disposition for survival analysis. In total, 94 subjects (50%) died during 493.5 person-years of observation. One-year mortality was 38% (n = 71) with a median survival time of 4.2 years (IQR 0.3–10.9) (Fig. 2). Hazard of death was higher in subjects age ≥ 65 (p = 0.028), but did not differ by sex, ability to follow commands at discharge, or presence of malignant neurological test results. Hospital readmissions were frequent, with 86 within 30 days, 150 within 90 days, 246 within one year. A total of 19% (n = 37) of patients had three or more hospital readmissions within one year of discharge. In total, 35% (n = 66), 48% (n = 101), and 58% (n = 111) of subjects were rehospitalized within 30, 90 days, and one year respectively. Median length of stay during readmissions was 8 days [IQR 3–19].

Fig. 2 –

Kaplan-Meier survival curve for entire cohort (A) and stratified by following commands at discharge (B), female sex (C), and age ≥ 65 (D).

Of 43 subjects who were unable to follow commands at discharge, 42% (n = 18) had at least one malignant neurological prognostic finding. Three subjects did not have any subsequent healthcare encounters noted in any available health record. Five (11%) followed commands on subsequent encounters (median time from discharge to a visit where they followed commands: 155 days, [IQR 39–198] (Tables 2 and 3). Only one of these subjects had a malignant prognostic finding: a 19-year-old male with brief out of hospital cardiac arrest, concomitant traumatic brain injury, and polytrauma had absent cortical (N20) responses on somatosensory evoked potentials. He began following commands 6.5 months after hospital discharge. In clinical notes, providers conveyed that his traumatic brain injury (TBI) rather than his cardiac arrest was the primary contributor to his brain injury and mental status. Nine patients (21%) were reported to be living at home on a repeat healthcare encounters. Of these, two were initially discharged to LTAC and seven were initially discharged to acute inpatient rehabilitation.

Table 2–

Characteristics and neurological testing of patients who did not follow commands at hospital discharge.

Characteristic	Did not follow commands during follow-up n = 38	Followed commands during follow-up n = 5
Age, years	59 [47–72]	55 [26–65]
Female sex	14 (37%)	2 (40%)
Out-of-hospital cardiac arrest	30 (78%)	5 (100%)
Initial rhythm
VT/VF	10 (26%)	2 (40%)
PEA	11 (29%)	2 (40%)
Asystole	14 (37%)	1 (20%)
Unknown	3 (8%)	0 (0%)
Witnessed status for out-of-hospital cardiac arrests
Bystander witnessed	18 (60%)	4 (80%)
EMS witnessed	4 (13%)	1 (20%)
Unwitnessed	6 (20%)	0 (0%)
Arrest in emergency department	2 (7%)	0 (0%)
CPR duration	15 [9 – 27]	16 [14–28]
Epinephrine doses (mg)	2 [1–4]	3 [3–5]
Pittsburgh Cardiac Arrest Category
I	1 (3%)	0 (0%)
II	11 (29%)	1 (20%)
III	4 (10%)	4 (80%)
IV	10 (26%)	0 (0%)
Unknown	12 (32%)	0 (0%)
Neurological prognostic testing
CT brain obtained	32 (84%)	3 (60%)
CT grey-white ratio	1.34 [1.27–1.36]	1.36 [1.29–1.44]
Grey-white ratio <1.2	3 (8%)	0 (0%)
Somatosensory evoked potentials obtained	22 (58%)	3 (60%)
N20 response
Bilaterally present	11 (50%)	2 (67%)
One side present, one side absent	2 (9%)	0 (0%)
Bilaterally absent	9 (41%)	1 (33%)
EEG obtained	35 (87%)	4 (80%)
BSIB	11 (31%)	0 (0%)
MRI brain obtained	22 (58%)	5 (100%)
Cortical diffusion restriction
No diffusion restriction	8 (36%)	1 (20%)
1–2 lobes	6 (28%)	2 (40%)
>3 lobes	8 (36%)	2 (40%)
Basal ganglia diffusion restriction Present
One or more malignant prognostic findings	17 (45%)	1 (20%)
Motor exam at hospital discharge
Localizing to pain	12 (34%)	3 (60%)
Flexion to pain	2 (6%)	1 (20%)
Extension to pain	3 (9%)	0 (0%)
No response to pain	15 (43%)	1 (20%)
Unable to determine	6 (16%)	0 (0%)
Disposition from acute care hospital
Home	0 (0%)	0 (0%)
Acute rehabilitation	4 (10%)	1 (20%)
Skilled nursing facility	17 (45%)	0 (0%)
Long-term acute care	16 (42%)	4 (80%)
Other inpatient hospital	1 (3%)	0 (0%)
Survived > 1 year after discharge	20 (53%)	0 (0%)

Abbreviations: CT – computed tomography; EEG – electroencephalography; BSIB – burst suppression with identical bursts; MRI – magnetic resonance imaging.

Table 3–

Characteristics of subjects that were noted to follow commands during subsequent encounters and did not follow commands at hospital discharge.

Subject	Clinical scenario	Arrest details	Arrest etiology	CTH GWR	SSEP	MRI radiologist interpretation	Discharge disposition and exam	Time to commands
1	26-year-old man with history of opioid use disorder found in bed unresponsive.	No bystander CPR, PEA initial rhythm, 14 minutes CPR, 5 mg epinephrine and 1 shock.	Toxicological	NA	NA	Diffusion restriction of cortical white matter of all lobes as well as dentate nuclei and the lentiform nuclei. Unclear if result of heroin inhalation vs. anoxic changes.	Long term acute care. No response to painful stimuli	155 days
2	55-year-old woman with history of hypothyroidism complained of shortness of breath, then collapsed in front of family.	Witnessed collapse, bystander CPR, asystolic initial rhythm, 37 minutes CPR, 7 mg epinephrine, 8 shocks.	Structural heart disease	NA	Present N20 response	Diffusely abnormal gyral edema and restricted diffusion compatible with severe hypoxic ischemic injury, also involving the caudate nuclei.	Long term acute care. Tracked examiner but fid not follow commands.	3 yrs & 2 months Noted following commands at well patient visit. Discharge from long term acute care to brain injury rehab is not in health system.
3	65-year-old man with history of schizophrenia and atrial fibrillation had a witnessed shaking episode and became unresponsive in front of family.	Witnessed collapse, bystander CPR, aystolic initial rhythm, 16 minutes CPR, 3 mg epinephrine, 3 shocks.	Unknown, inconclusive workup but presumed seizure with unclear cause	1.36	NA	No territorial infarct or evidence of diffuse anoxic brain injury.	Long term acute care. Startles but does not track or follow commands	21 days
4	67-year-old woman with history of hypertension pulled off road while driving and collapsed in view of bystanders.	Witnessed collapse, bystander CPR, VT/VF initial rhythm, 28 minutes CPR, 3 mg epinephrine, 6 shocks.	Acute coronary syndrome	1.44	Present N20 response	Cortical edema and gyriform restricted diffusion in the bilateral parietal, medial frontal, and posterior temporal lobes consistent with hypoxic ischemic injury.	Long term acute care. Tracked examiner but did not follow commands.	39 days
5	19-year-old man with no medical history fell and was pinned by bulldozer, with concomitant TBI and polytrauma.	Witnessed trauma, bystander CPR, VT/VF initial rhythm, 5 minutes CPR, 0 mg epinephrine, 1 shock.	Tension pneumothorax	1.29	Absent N20 response	Bilateral decompressive craniectomies with unchanged herniation of the brain through the surgical defects. Findings consistent with diffuse axonal injury corresponding to grade II given the involvement of the corpus callosum.	Acute rehabilitation. Startles but does not track or follow commands	198 days

Discussion

We report long-term survival and hospital readmission in cardiac arrest survivors with severe functional impairment at the end of acute care hospitalization. These patients are frequently discharged to SNFs or LTACs. Hospital readmissions are common. About 11% of patients who were unable to follow commands at discharge ultimately followed commands during subsequent healthcare encounters and 21% returned to living at home.

Hospital and long-term survival after in and out of hospital cardiac arrest have steadily improved.¹⁸ The American Heart Association has issued a scientific statement highlighting the needs and unique symptoms including chronic musculoskeletal, neurological, and cognitive impairments of this growing patient population.¹⁹ While these guidelines focus on reintegrating survivors who have mild to moderate impairments into society and addressing their family needs, there is a knowledge gap about the course of survivors with high functional dependence or persistent DoC. Our data provide a description of this subgroup.

Long-term outcomes vary among cardiac arrest survivors with DoC who are admitted to specialized rehabilitation centers.^6,7 Some patients have potential to gain considerable independence in mobility and self-care despite persistent cognitive impairment.^6,7 However, in our cohort only 12% of our patients with who were unable to follow commands were accepted to inpatient rehabilitation immediately after the acute hospitalization. Moreover, specialized DoC programs are scarce and often limited to younger patients.²⁰ More than half of the subjects of our study were dispositioned to skilled nursing facilities and long-term acute care facilities. Including this less-selected cohort of survivors may explain the overall worse trajectories we observed in this study compared to those reported in rehabilitation cohorts.

In addition to the neurological sequela of cardiac arrest, critical illness can leave patients with neuromuscular weakness and muscle wasting,²¹ as well as exacerbate or uncover frailty,²² both of which can lead to reduced functional capacity and limited ability to participate in rehabilitation activities at hospital discharge. Severity of functional dependency is an independent predictor of subacute mortality in general ICU patients that survive to hospital discharge.²³ Medical complications are associated with poorer outcomes in rehabilitation cohorts.^24–26 We found hospital readmission to be frequent. Our study may underestimate the total burden of healthcare utilization because we only examined encounters that result in hospitalization, and many other complications may arise have been treated at the patient’s residence, outpatient visits, or the emergency department.

Of subjects discharged from the hospital unable to follow commands, 5 (11%) regained this function with only one case having a malignant prognostic test. In this particular case, traumatic brain injury was felt to be the prominent neurological injury, illustrating that absent N20 cortical responses on SSEP may have different prognostic implications after trauma than after cardiac arrest.²⁷ Our data are similar to another series of 63 cardiac arrest patients with persistent unresponsive wakefulness syndrome at hospital discharge, of whom only 2 of 63 improved during follow up.²⁸

While a wide array of neurological prognostic tests, biomarkers, and examination features are felt to be highly specific for poor neurological outcome,¹⁴ many patients have indeterminate prognostic results. It is difficult to predict the potential degree of return of cognitive ability and functional capacity in this clinical scenario. Further characterizing DoC patients with functional MRI, specialized EEG analyses, or other modalities may provide future strategies to predict who will improve over subsequent months.^29,30 Until these techniques are more widely available, decision makers and clinical teams still face difficult decisions about WLST or longer-term support in DoC patients with uncertain potential for recovery. Caregivers and families also have risk for being unable to provide the high-intensity support that these patients require.^31,32 Our data may help inform such decisions and allow families to anticipate the burden or preemptively seek additional emotional, financial, and social support.

Limitations

Our work has several limitations. While over 3,000 cardiac arrest patients were treated over a 10-year period at our facility, we only identified 190 patients discharged with severe functional disability and 43 who were unable to follow commands. This is likely because WLST for anticipated poor neurological outcomes is common in North America, raising the possibility that our cohort is somehow selected for patient with higher probability of improvement. Other cultures where WLST is rare and long-term support of DoC patients is common may have less selected cohort in whom to measure outcomes. Severity of DoC is broad, ranging from persistent coma to minimally conscious.²⁹ We were unable to definitively classify patients into severity of DoC or define trajectory of examination retrospectively, thus chose to classify patients based on ability to follow commands at discharge. Prospective evaluation of these patients with serial, formal coma recovery scale examinations is required to overcome this limiation. We reviewed for improvement in neurological status by reviewing available data but 7% of the cohort had no subsequent healthcare encounters. This likely reflects both imperfect capture, where patients received care outside our health record system and mortality bias, where subjects died before an encounter could occur. This limitation may bias our results towards more pessimistic estimates of improvement. A multi-center registry of cardiac arrest patients with DoC might address these limitations and better characterize the long-term trajectory of this population. Finally, it is unclear from our data if deaths during the follow up period were from medical complications or represent WLST or limitations of care.

Conclusions

Over a ten-year period, about 20% of cardiac arrest survivors were discharged from the hospital with severe functional and neurological disability. A majority of these patients are discharged to skilled nursing or long-term acute care facilities. Mortality is high, and hospital readmissions are frequent. Of patients with DoC at hospital discharge, over half had indeterminant neurological prognosis and few (11%) regained the ability to follow commands. These data can help inform decision maker expectations for patient trajectory and life expectancy.