Brief Report

cranial computed tomography in the resuscitated patient with cardiac arrest

Robin Naples MD, Elizabeth Ellison MD, William J. Brady MD?

Department of Emergency Medicine, University of Virginia, Charlottesville, VA 22908, USA

Received 17 October 2007; revised 22 December 2007; accepted 1 January 2008

Abstract

Introduction: The incidence of out-of-hospital and in-hospital cardiorespiratory arrest from all causes in the United States occurs not infrequently. postresuscitation care should include the identification of the inciting arrest event as well as therapy tailored to support the patient and treat the primary cause of the decompensation. The application of one particular testing modality, Cranial computed tomography of the head, has not yet been determined. We undertook an evaluation of the use of head CT in patients who were resuscitated from cardiac arrest.

Methods: Prehospital (emergency medical services), ED, and hospital records were reviewed for patients of all ages with cardiorespiratory arrest over a 4-year period (July 1996-June 2000). Information regarding diagnosis, management, and outcome was recorded. The results of cranial CT, if performed, and any apparent resulting therapeutic changes were recorded. Patients with a known traumatic mechanism for the cardiorespiratory arrest were excluded.

Results: A total of 454 patients (mean age 58.3 years with 60% male) with cardiorespiratory arrest were entered in the study with 98 (22%) individuals (mean age 58.5 years with 53% male) undergoing cranial CT. Arrest location was as follows: emergency medical services, 41 (42%); ED, 11 (11%); and hospital, 46 (47%). Seventy-eight (79%) patients demonstrated 111 CT abnormalities: edema, 35 (32%); atrophy,

24 (22%); extra-axial hemorrhage, 14 (13%); old infarct, 12 (11%); new infarct, 11 (10%);

Intraparenchymal hemorrhage, 6 (5%); Skull fracture, 5 (4%); mass, 3 (2%); and foreign body, 1 (1%). Therapeutic and diagnostic alterations in care were made in 38 (39%) patients-35 abnormal and 3 normal CTs. The following alterations occurred: medication administration, 26; withdrawal of life support, 7; additional diagnostic study, 6; neurologic consultation, 6; and intracranial pressure monitoring. 4. No patient survived to discharge.

Conclusion: In this subset of resuscitated patients with cardiac arrest, abnormalities on the head CT were not uncommon. Alterations in management did occur in those patients with abnormalities. The indications and impact of head CT in the population of resuscitated patients with cardiac arrest remain unknown, warranting further investigation.

(C) 2009

Introduction

* Corresponding author.

E-mail address: [email protected] (W.J. Brady).

The incidence of out-of-hospital cardiorespiratory arrest from all causes in the United States is estimated to be 55 cases per 100000 people [1]. In-hospital cardiorespiratory arrests

0735-6757/$ - see front matter (C) 2009 doi:10.1016/j.ajem.2008.01.014

from all causes account for an additional 54.1 events per hospital per year [2]. Recent advances have been made in the postresuscitation care of a subset of these patients with the initiation of Serum glucose control, blood pressure manage- ment, and therapeutic hypothermia, among other techniques, that can alter the outcome in these extremely ill individuals [3]. In another area of important postresuscitation care, the most appropriate use of Cranial computed tomography , however, has not yet been determined [4]. The determination of significant intracranial abnormality in these resuscitated patients has bearing on their immediate care. For instance, the patient with significant subarachnoid hemorrhage likely would require a number of therapeutic interventions tailored to the central nervous system event, including the avoidance of anticoagulant/antiplatelet therapies, perfor- mance of CT angiography, and neuro-critical care consulta- tion. Without the clinical awareness of this diagnosis provided by CT scanning, none of these therapies would be considered. We retrospectively reviewed the charts of resuscitated patients with cardiorespiratory arrest at our facility to assess how often CT was performed, whether abnormal findings were present, and if so, what Changes in management were

made based on these findings.

Methods

Study design

Prehospital, ED, and hospital records were reviewed for patients of all ages with cardiorespiratory arrest. Patients were identified as noted in the Population subsection of this section; a retrospective cohort analysis of this population was performed. The use of cranial CT scanning was determined based upon review of medical records. The study was reviewed by the institution’s internal review board and considered exempt owing to its retrospective nature.

Setting

The setting of the study was a university hospital ED level 1 trauma center with an Annual patient volume of 60000 serving a primarily suburban and rural area with an urban section of approximately 40 000 persons; the general population of the area is approximately 120000. The study period was 1 year, from July 1996 to June 2000.

Population

The patients were located using a medical records search of both hospital and ED registries. Patients were considered to have cardiac arrest if they were determined to be pulseless and apneic, cardiopulmonary requiring resuscitation. The patient was considered to have return of spontaneous circulation if pulse and blood pressure were recorded in the

setting of a perfusing cardiac rhythm. Resuscitated patients underwent cranial CT scanning at the discretion of the treating physician. Patients with a known traumatic mechan- ism for the cardiorespiratory arrest were excluded.

Measurements

Medical records (out-of-hospital, ED, and hospital charts) were reviewed by the investigators using a standardized data collection form. This form was reviewed and agreed upon by the investigators before the initiation of the study. Informa- tion was then entered into a computer database by the investigators using Microsoft Excel 5.0 software (Microsoft Corp, Redmond, Wash). Clinical data regarding diagnosis, management, and outcome were recorded. The results of cranial CT, if performed, and any apparent resulting therapeutic changes were recorded. Therapeutic alterations were noted if the change occurred after performance of the cranial CT result was available.

Results

Four hundred fifty-four patients (mean age 58.3 years with 60% male) with cardiorespiratory arrest were entered in the study with 98 (22%) individuals (mean age 58.5 years with 53% male) undergoing cranial CT (Fig. 1). Arrest location was as follows: emergency medical services, 41 (42%); ED, 11 (11%); and hospital, 46 (47%). Seventy-eight (79%) patients demonstrated 111 CT abnormalities (Fig. 2):

edema, 35 (32%); atrophy, 24 (22%); extra-axial hemor-

rhage, 14 (13%); old infarct, 12 (11%); new infarct, 11 (10%); intraparenchymal hemorrhage, 6 (5%); skull fracture, 5 (4%); mass, 3 (2%); and foreign body, 1 (1%). Therapeutic and diagnostic alterations in care were made in 38 (39%) patients-35 abnormal and 3 normal CTs. The following alterations occurred (Fig. 3): medication administration, 26; withdrawal of life support, 7; additional diagnostic study, 6; neurologic consultation, 6; and intracranial pressure mon- itoring, 4. No patient survived to discharge.

Discussion

In our study, cranial CT was performed infrequently after cardiorespiratory arrest. In those patients who did undergo CT examination, however, a significant number and range of abnormalities were found. Changes were made in the therapeutic plans of not only the patients with abnormal findings, but also in a small percentage of those with Normal CT scan results. A normal cranial CT may allow the treating physician more aggressive pharmacologic management after arrest. Conversely, many of the abnormalities found could preclude the use of anticoagulation or even necessitate directed pharmacologic or surgical therapy.

Fig. 1 Study patients.

Approximately one third of the patients undergoing CT demonstrated edema, an indicator of hypoxic injury. Cytotoxic edema has been shown in the feline model to occur in the brain resulting from decreased levels of adenosine triphosphate from hypoperfusion and global ischemia [5,6]. In addition, the medullary draining veins become distended with blood causing increased white matter density [5,7,8]. A combination of edema and venous distension can occasionally cause significant increases in intracerebral pressure necessitating intracerebral pressure monitoring as demonstrated in 4 of our patients. Limited data

Fig. 2 The abnormalities noted on cranial CT scan (n = 78 patients with 111 abnormalities).

also suggest that cerebral edema and loss of gray-white matter differentiation can be used for predicting the severity of hypoperfusion and neurologic outcome-thus serving as a prognostic marker for patient recovery [9,10].

A smaller, though significant, portion of our patients demonstrated intracranial hemorrhage, either extra-axial (13%) or intraparenchymal (5%). These patients present an interesting and challenging subset of patients with post- cardiorespiratory arrest. From the study by Kurkciyan et al [11], 4% of patients presenting to their hospital had spontaneous SAH as a cause of their cardiorespiratory arrest. Of the patients who were found to have spontaneous

Fig. 3 Therapeutic and diagnostic alterations in care after cranial CT scan were noted in 38 (39%) patients-35 with abnormal and 3 with normal cranial CTs.

SAH, 39% of them complained of headache prearrest [11]. Often, it is difficult to obtain an accurate history from family or bystanders in the critical early phase of care in the ED. Also, Neurologic examinations on postarrest patients can be unreliable owing to medications which they have received during their prehospital care or the limitations of their comatose state. The presence of intracranial hemorrhage may have important implications in treatment plans with the administration of fresh frozen plasma to reverse coagulopathies, addition of anticonvul- sants for seizure prophylaxis, or involvement of neuro- intensivists. The presence of intracerebral hemorrhage may also limit the use of therapeutic hypothermia which could cause increased bleeding.

In addition to cerebral edema and intracranial hemor- rhage, other substantial abnormalities were found. The discovery of Skull fractures, masses, and foreign body impacts the continued management of resuscitated patients with cardiorespiratory arrest. Skull fractures may occur from the trauma of the inciting arrest event. Although large, open, or depressed skull fractures will likely be found on examination, more subtle closed skull fractures may be missed. The presence of skull fractures may indicate more significant closed head injury in the comatose patient. In addition, the location of the skull fracture may necessitate neuroSurgical consultation and monitoring for the develop- ment of extra-axial hemorrhage, specifically epidural hematomas, in a patient whose clinical exam may be limited. Along with skull fractures, the presence of intracerebral masses and foreign bodies would prompt subspecialty consultation. The diagnosis of a new cerebral mass would have implications on medical management and possible surgical intervention. The long-term prognosis and goals of care in the patient subsequently may be changed based on the type of mass or the need for surgery.

The presence of new infarction on the cranial CT, which was seen in 10% of our population, clearly has import for acute management issues as well as long-term recovery plans. Although none of our patients survived to discharge, the presence of recent infarction allows the management team to include neurologic critical care as well as aid in family discussion regarding expectations of postarrest rehabilitation and to establish appropriate long-term therapy goals.

The detection of prior Ischemic infarction, although important to understanding the patient’s overall clinical situation, likely has little impact on immediate management issues. Prior infarction, of course, can signify the presence of other comorbid illnesses that patients with cardiorespiratory arrest often have-which can influence potential recovery and rehabilitation [3].

Finally, certain CT findings can be age related. For instance, cerebral atrophy may be expected in this patient population. The median age was more than 58 years in our study and from prior investigations, atrophy can be commonly found in men after the age of 40 and women

after 50 years of age [12-14]. This finding, although an abnormality, is not only expected in this patient population but also has little impact on management strategies in the postresuscitation care phase of the hospital course.

Limitations

This investigation is a limited, retrospective study considering both out-of-hospital and in-hospital cardior- espiratory arrest. One would presume that there is variability in the etiology of cardiorespiratory arrest in out-of-hospital vs in-hospital patients and that patients currently receiving in-patient medical care would have a greater rate of known cause of arrest obviating the need for a CT. This issue demonstrates the heterogeneous nature of this patient population-and the resultant implications for management. Also, we were unable to ascertain the clinical findings that prompted the performance of the cranial CT; thus, it is unknown whether there were focal neurologic deficits after return of spontaneous circulation or pertinent preceding history that would prompt further diagnostic work-up with CT. As there were no survivors in this cohort, it is impossible to say whether changes in management had any impact.

Conclusion

Cranial CT is applied in a minority of patients with cardiorespiratory arrest in our institution. However, when CT is performed, abnormalities are found frequently and alterations in management are made in certain cases. At this time, it is the discretion of the treating physician whether or not to obtain neurologic imaging after successful resuscitation based on historical and clinical data. Further investigation is required to aid the physician in determining the appropriate patient population for CT as well as the true impact of such radiographic imaging.

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