critical care medicine
Cardiopulmonary Resuscitation (CPR) in Adults
Postresuscitative Care
Restoration of spontaneous circulation (ROSC) is only an intermediate goal in resuscitation. The ultimate goal is survival to hospital discharge with good neurologic function, which is achieved by only a minority of patients with ROSC. To maximize the likelihood of a good outcome, clinicians must provide good supportive care (eg, manage blood pressure, temperature, and cardiac rhythm) and treat underlying conditions, particularly Overview of Acute Coronary Syndromes (ACS) . Postresuscitative care includes mitigation of reperfusion injury occurring after the period of ischemia. Postresuscitative care should begin immediately after spontaneous circulation is determined. Oxygen administration should be titrated down to an SpO2 of 94% to minimize hyperoxic damage to lungs. Ventilation rate and volume should be titrated to an end-tidal carbon dioxide reading of 35 to 40 mm Hg. A fluid bolus should be administered if tolerated, as well as vasopressor infusion. Postresuscitation laboratory studies include arterial blood gases (ABG), complete blood count (CBC), and blood chemistries, including electrolytes, glucose, BUN (bloodureanitrogen), creatinine, and cardiac markers. (Creatine kinase is usually elevated because of skeletal muscle damage caused by CPR; troponins, which are unlikely to be affected by CPR or defibrillation, are preferred.) Arterial PaO2 should be kept near normal values (80 to 100 mm Hg). Hematocrit should be maintained at≥30% (if cardiac etiology is suspected), and glucose at 140 to 180 mg/dL (7.7 to 9.9 mmol/L); electrolytes, especially potassium, should be within the normal range. The decision to do Cardiac Catheterization after resuscitation from cardiac arrest should be individualized based on the electrocardiogram (ECG), the interventional cardiologist's clinical impression, and the patient's prognosis. Current guidelines suggest doing emergency angiography (within 2 to 6 hours) for adult patients in whom a cardiac cause is suspected and who have ST-segment elevation (STEMI) on ECG. It is unclear whether emergency (within 2 hours) or more delayed (median about 120 hours after arrest) cardiac catheterization in patients without STEMI on ECG results in any clinical benefit ( Postresuscitative care references ). Some researchers advocate liberal use of cardiac catheterization after ROSC, doing the procedure on most patients unless the etiology is clearly unlikely to be cardiac (eg, drowning) or there are contraindications (eg, intracranial bleeding). ) at hospital discharge. A CPC score of 1 is indicative of good cerebral performance (patient is conscious, alert, able to work but may have mild neurologic or psychologic deficit). A CPC score of 2 is indicative of moderate cerebral performance (patient is conscious, able to do activities of daily living [ADLs] and work in a simple environment). Hypoxic brain injury is a result of ischemic damage and cerebral edema (see Pathophysiology ). Both damage and recovery may evolve over 48 to 72 hours after resuscitation. Maintenance of oxygenation and cerebral perfusion pressure (avoiding hyperventilation, hyperoxia, hypoxia, and hypotension) may reduce cerebral complications. Both hypoglycemia and hyperglycemia may damage the post-ischemic brain and should be treated. is recommended for patients who remain unresponsive after spontaneous circulation has returned ( Postresuscitative care references ). Current recommendations are to target normothermia (< 37.5º C), although many researchers and clinicians continue to advocate for hypothermia (body temperature of 32 to 36° C). Regardless of the chosen target temperature, active temperature management is begun as soon as spontaneous circulation has returned. Techniques to induce and maintain hypothermia can be either external or invasive. External cooling methods are easy to apply and range from the use of external ice packs to several commercially available external cooling devices that circulate high volumes of chilled water over the skin. For internal cooling, chilled IV fluids (4° C) can be rapidly infused to lower body temperature, but this method may be problematic in patients who cannot tolerate much additional fluid volume. Also available are external heat-exchange devices that circulate chilled saline to an indwelling IV heat-exchange catheter using a closed-loop design in which chilled saline circulates through the catheter and back to the device, rather than into the patient. Another invasive method for cooling uses an extracorporeal device that circulates and cools blood externally then returns it to the central circulation. Regardless of the method chosen, the goal is to cool the patient rapidly and to maintain the core temperature at target (< 37.5º C for normothermia or between 32° C and 36° C for hypothermia) for 24 hours after restoration of spontaneous circulation. Currently, there is no evidence that any specific temperature within this range is superior, but it is imperative to avoid hyperthermia ( Numerouspharmacologic treatments,including free radical scavengers, antioxidants, glutamate inhibitors, and calcium channel blockers, are of theoretic benefit. Many have been successful in animal models, but none have proved effective in human trials. Current recommendations are to maintain a mean arterial pressure (MAP) of>65 mm Hg and systolic blood pressure>90 mm Hg. In patients known to be hypertensive, a reasonable target is systolic blood pressure 30 mm Hg below prearrest level. MAP is best measured with an intra-arterial catheter. Use of a flow-directed pulmonary artery catheter for hemodynamic monitoring has been largely discarded. Blood pressure support includes IV crystalloid infusion (normal saline or lactated Ringer's) Inotropic or vasopressor drugs with a goal of maintaining systolic blood pressure of at least 90 mm Hg and MAP of at least 65 mm Hg Rarely intra-aortic balloon counterpulsation Patients with low MAP and low central venous pressure should have IV fluid challenge with 0.9% saline infused in 250-mL increments. Although use of inotropic and vasopressor drugs has not proved to enhance long-term survival, older adults with moderately low MAP (70 to 80 mm Hg) and normal or high central venous pressure or widened IVC as assessed by bedside ultrasonography may receive an infusion of an inotrope (eg,dobutaminestarted at 2 to 5 mcg/kg/minute). Amrinone ormilrinoneare alternatives that are rarely used (see table). If this therapy is ineffective, the inotrope and vasoconstrictordopaminemay be considered. Alternatives areepinephrineand the peripheral vasoconstrictorsnorepinephrineandphenylephrine(see table). However, vasoactive drugs should be used at the minimal dose necessary to achieve low-normal MAP because they may increase vascular resistance and decrease organ perfusion, especially in the mesenteric bed. They also increase the workload of the heart at a time when its capability is decreased because of postresuscitation myocardial dysfunction. If MAP remains<70 mm Hg in patients who may have sustained a myocardial infarction (MI), intra-aortic balloon counterpulsation should be considered. Patients with normal MAP and high central venous pressure or widened IVC may improve with either inotropic therapy or afterload reduction withnitroprussideornitroglycerin. Intra-aortic balloon counterpulsation can assist low-output circulatory states due to left ventricular pump failure that is refractory to drugs. A balloon catheter is introduced via the femoral artery, percutaneously or by arteriotomy, retrograde into the thoracic aorta just distal to the left subclavian artery. The balloon inflates during each diastole, augmenting coronary artery perfusion, and deflates during systole, decreasing afterload. Its primary value is as a temporizing measure when the cause of shock is potentially correctable by surgery or percutaneous intervention (eg, acute MI with major coronary obstruction, acute mitral insufficiency, ventricular septal defect). Although Ventricular Fibrillation (VF) (VF) or Postresuscitation rapid supraventricular tachycardias occur frequently because of high levels of beta-adrenergic catecholamines (both endogenous and exogenous) during cardiac arrest and resuscitation. These rhythms should be treated if extreme, prolonged, or associated with hypotension or signs of coronary ischemia. AnesmololIV infusion is given, beginning at 50 mcg/kg/min. Patients who had arrest caused by VF or VT not associated with acute myocardial infarction are candidates for an Implantable Cardioverter-Defibrillators (ICD) (ICD). ICDs are implanted similarly to pacemakers and have intracardiac leads and sometimes subcutaneous electrodes. They can sense arrhythmias and deliver either cardioversion or cardiac pacing as indicated. 1.Spoormans EM, Lemkes JS, Janssens GN, et al: Ischaemic electrocardiogram patterns and its association with survival in out-of-hospital cardiac arrest patients without ST-segment elevation myocardial infarction: a COACT trials' post-hoc subgroup analysis.Eur Heart J Acute Cardiovasc Care11(7):535-543, 2022. doi:10.1093/ehjacc/zuac060 2.Bernard SA, Gray TW, Buist MD, et al: Treatment of comatose survivors of out-of-hospital cardiac arrest with induced hypothermia.N Engl J Med346:557–563, 2002. doi: 10.1056/NEJMoa003289 3.Nielsen N, Wetterslev J, Cronberg T, et al: Targeted temperature management at 33°C versus 36°C after cardiac arrest.N Engl J Med369:2197–2206, 2013. doi: 10.1056/NEJMoa1310519 4.Granfeldt A, Holmberg MJ, Nolan JP, Soar J, Andersen LW; International Liaison Committee on Resuscitation (ILCOR) Advanced Life Support Task Force: Targeted temperature management in adult cardiac arrest: Systematic review and meta-analysis.Resuscitation167:160–172, 2021. doi:10.1016/j.resuscitation.2021.08.040 5.Wyckoff MH, Greif R, Morley PT, et al: 2022 International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science With Treatment Recommendations: Summary From the Basic Life Support; Advanced Life Support; Pediatric Life Support; Neonatal Life Support; Education, Implementation, and Teams; and First Aid Task Forces.Circulation146(25):e483–e557, 2022. doi:10.1161/CIR.0000000000001095 