Results of the implementation of integrated care after cardiorespiratory arrest in a university hospital

ABSTRACT Objectives: to identify the care measures performed after cardiorespiratory arrest (CRA) and to relate them to the neurological status and survival at four moments: within the first 24 hours, at the discharge, six months after discharge, and one year after discharge. Method: retrospective, analytical and quantitative study performed at the Emergency Department of a university hospital in São Paulo. Eighty-eight medical records of CRA patients who had a return of spontaneous circulation sustained for more than 20 minutes were included and the post-CRA care measures performed in the first 24 hours were identified, as well as its relationship with survival and neurological status. Results: the most frequent post-CRA care measures were use of advanced airway access techniques and indwelling bladder catheterization. Patients who had maintained good breathing and circulation, temperature control and who were transferred to intensive care unit had a better survival in the first 24 hours, after six months and one year after discharge. Good neurological status at six months and one year after discharge was associated with non-use of vasoactive drugs and investigation of the causes of the CRA. Conclusion: the identification of good practices in post-CRA care may help to reduce the mortality of these individuals and to improve their quality of life.


Study approved by the Ethics and Research
Committee of the Federal University of São Paulo (CAEE: 52531315.4.0000.5505).
The study had a retrospective, analytical and quantitative approach, and it was carried out in the Emergency Room (ER) of a university hospital in the city of São Paulo (SP), Brazil.
All adult patients who had CRA in out-of-hospital settings and were taken for assistance at the ER of the above mentioned service in the year 2011, and who presented RSC sustained for more than 20 minutes were included in this study, totaling 88 patients. We excluded from this study the CRA cases assisted in other sectors of the hospital.
Data collection was performed in four different moments through the analysis of medical records. At admission, the following variables were collected: age, gender, skin color, presence of comorbidities, previous CRA events, pre-CRA neurological status, presence of consciousness, breathing and pulse at the arrival of the patient in the ER, place where the CRA occurred, if there were witnesses, presumed immediate cause, initial rhythm of CRA and interventions performed during care (5) .
During the first 24 hours; the following post-CRA care measures were identified and recorded: use of advanced airway access techniques; monitoring of respiratory rate; maintenance of respiratory rate between 10 and 12 rpm; monitoring of pulse oximetry; maintenance of oxygen saturation between 94 and 96%; maintenance of CO 2 partial pressure between 40 and 45 mmHg; monitoring of capnography; maintenance of end-expiratory CO 2 (6) .
In this study, patients diagnosed with CPC 1 and 2 were considered to be in good neurological state, and those evaluated and classified as CPC 3, 4 and 5, were in poor neurological state (6) .

Results
Demographic and clinical data are presented in  The mean time between initiation of CPR and the first shock was 7.8 minutes; between the initiation of CPR and installation of advanced airway access was 4.1 minutes; between the initiation of CPR and the first dose of epinephrine was 2.1 minutes; and the mean duration of CPR was 11.1 minutes.
Post-CPR care performed in the first 24 hours after the RSC is shown in Table 3. Of the 88 medical records analyzed, 8 did not contain sufficient information to collect data, totaling 80 charts.
Monitoring of capnography and venous oxygen saturation and electroencephalogram were not performed in any patient. Of the 88 patients surveyed, 13 survived at discharge, 10 after six months, and 9 after one year. The variables that were significantly associated with greater patient survival are presented in Table 4.
Realization of post-CRA care was not associated with greater survival of individuals at hospital discharge.  and one year (p = 0.02) after discharge hospital.

Discussion
According to the guidelines of the American Heart Association, post-CRA care aims to reduce early mortality due to hemodynamic instability and to limit later multiple organ failure and brain injury. This care includes adequate cardiopulmonary conditions and perfusion of vital organs; safe transportation to intensive care units; early recognition of the causes of the event, and treating and preventing its recurrence; controlled temperature to minimize neurological damage; diagnosis and treatment of acute myocardial ischemia; ventilatory support with mechanical ventilation to limit lung injury; reducing the risk of multiple organ failure; assessment of neurological recovery prognosis; and promotion of rehabilitation of survivors (3) .
The mean age of the patients in this study was 66.2 years, as in a study carried out in Singapore by the National Emergency Ambulance System (7) . There was a prevalence of conscious, white people, breathing and with pulse at admission, and the predominant rhythm was pulseless electrical activity, a result that is different from that reported in the international literature (7) . Such findings may be associated with the fact that most events occurred in the in-hospital setting, in more complex patients, and with other associated comorbidities (8) .
In this study, maintenance of systolic blood and system perfusion, since death due to multiple organ failure is associated with a persistent low cardiac output in the first 24 hours after CPR (2) .
Advanced airway access was frequently performed in the patients in this study. In these cases, ventilation and oxygenation should be immediately optimized, thus avoiding hyperoxia, which contributes to an increase in oxidative stress and is associated with a worse neurological prognosis (2,6) . A study evaluated 173 comatose patients after sudden cardiac arrest and found that those who had lower maximum partial pressure of arterial oxygen in the first 24 hours after cardiac arrest had higher survival rates at discharge compared to the others (9) . In addition, cerebral vasoconstriction aggravated by hyperventilation potentiates ischemic brain injury (10) and reduces cardiac output at the expense of an increase in intrathoracic pressure (3) .
As for prevention of brain injury, the most frequent care measure in this study was the prevention of hyperthermia and continuous sedation. Studies have shown that patients who reached temperature above 37.6ºC after the return of the spontaneous circulation had lower survival chance and worse neurological prognosis in relation to the normothermic ones (3) . Evidence on prevention of post-CRA hyperthermia is still not well established, but the occurrence of fever is associated with worsening of neurological injury in patients undergoing intensive care for other conditions (11) . Thus, the fight against fever is recommended because of the potential aggravation of ischemic brain damage (3) . Other neuroprotective measures are recommended, such as the prevention of seizures and the continuous monitoring of brain activity through electroencephalogram (6) .
When post-CRA care and 24-hour survival were associated, the variables: respiratory rate; oxygen saturation; IBP and NIBP; body temperature; maintenance of oxygen saturation between 94 and 96%; SBP greater than or equal to 90 mmHg; MAP greater than or equal to 65 mmHg; urine output of 0.5-1 ml/kg/ Six months after discharge, maintenance of oxygen saturation between 94 and 96%, non-administration of vasoactive drugs and transfer of the patient to the ICU were related to higher survival rates. In a study performed with out-of-hospital cardiorespiratory arrest patients, it was observed that increased partial oxygen pressure (PaO 2 ), greater than 300 mmHg, during CPR were associated with higher rates of return to spontaneous circulation and better neurological outcomes when compared to normal or lower partial oxygen pressure (PaO 2 of less than 60 mmHg) (12) .
Prevention of hypoxemia is considered more important than avoiding any potential risk of hyperoxia (3) .
Regarding the administration of vasoactive drugs, studies evaluating specific strategies to improve blood pressure comparing vasopressors and fluids are scarce.
A study performed with patients who achieved a return to spontaneous circulation after CPR found that MAP greater than 70 mmHg in the first 6 hours after CPR was associated with good neurological function (13) . Although there was no consensus regarding the ideal values of MAP, the importance of strict monitoring to maintain effective circulation is emphasized, mainly in order to avoid hypotension in order to obtain better results after a CRA.
Transfer of post-CRA patients to the ICU may be related to greater survival rates because an ICU is a safer and better treatment environment for critical patients in view of its infrastructure with more advanced materials and equipment, as well as qualified personnel to provide specialized assistance (2)(3) .
In this study, at one year after discharge, the variables that were significantly associated with  (3) .
Regarding the neurological state of the individuals, those who did not receive vasoactive drugs had a better six-month and one-year neurological prognosis. Brain injury is an important cause of post-CRA morbidity and mortality. Recognition of its pathophysiological mechanisms and its correlation with patient characteristics, CPR maneuvers, and post-CRA care may improve the prognosis of these individuals (14) .
Hemodynamic stabilization, MAP greater than 65 mmHg, can often only be achieved with the use of vasoactive drugs and is critical for effective cerebral circulation after a CRA. Good hemodynamic parameters are related to higher survival rates at hospital discharge and better long-term neurological outcomes (3) . However, further studies on vasoactive drugs are necessary because, depending on the mechanism of action of such drugs, they may lead to changes in peripheral vascular resistance, heart rate, arrhythmias and myocardial ischemia (15) .
Differential diagnosis of the cause of CRA is paramount for establishing definitive treatment (2) , and in this study, it was related to a higher patient survival at six months and one year after hospital discharge.
Detecting the cause of the CRA can be difficult and often implies frequent reassessment of the patient through collection of information, clinical evaluation, blood profile and imaging tests (2) . More studies on this subject are necessary to elucidate the role of new resources to optimize the diagnosis of the causes of CRA and their reversal, as well as measures to help in the determination of patient prognosis (16) .
The main limitation of this study was to have been performed in a single center, which may not represent other realities. In addition, because this was a retrospective study, there were difficulties during collection, such as medical records with incomplete data and difficult to interpret.