Cardiopulmonary resuscitation (2024)

The explosion of the atomic bomb in 1945 has become a symbol of the explosion of technology during this century. Unfortunately, the human ability to oversee technological advancements in logical and sensible ways has lagged. In 20^th century medicine, the universal application of the procedure of cardiopulmonary resuscitation (CPR) exemplifies this problem. One should ask whether CPR is always indicated. Fortunately, alternative approaches for managing the end of life, withdrawing life sustaining care and not providing CPR, have been proposed (Prendergast et al. 1998). These proposals focus primarily on recognition of futile care. A secondary consideration is the recognition that the cost of injudiciously applied CPR has been estimated to average hundreds of thousands of dollars for each survivor (Lee et al. 1996). Survival rates of CPR are variable, but average approximately 10%. Cardiopulmonary resuscitation is unquestionably one of the least constructive procedures performed in the intensive care unit (ICU).

Medical decision making regarding the therapies of CPR is unique. Basic life support (BLS) and advanced cardiac life support (ACLS) techniques are performed with implicit patient consent. Advance directives provide the only opportunity for patient autonomy. In the absence of a known advanced directive demonstrating that the patient wishes to refuse CPR therapies, the standard response by health care providers is to perform BLS and ACLS. The application of CPR is often viewed by patients, families, and health care providers as undignified and grotesque. It is often emotionally draining to families and health care teams. Because of these features and since the outcomes are almost universally poor, it is useful to apply common sense and the ethical concept of futility when considering CPR in the ICU.

Definition, pathogenesis, and epidemiology

Cardiopulmonary arrest is loss of airway, breathing, or meaningful circulation.

Cardiopulmonary resuscitation (CPR) is the use of therapeutic interventions, primarily BLS and ACLS, that are designed to restore spontaneous circulation following cardiac or pulmonary arrest. Once spontaneous circulation has been restored, patients require continued aggressive resuscitation to treat additional problems-for example, cardiac dysrhythmias, hypovolemia, metabolic acidosis, and acute renal failure. This stabilization phase is carried out in the ICU. Additionally, supportive ICU care is provided until a prognosis can be determined.

BLS - The goal of BLS is to provide support of breathing and circulation until the cause of the arrest can be corrected. BLS techniques involve establishing an airway (excluding tracheal intubation), breathing, and closed chest compression.

ACLS - The goal of ACLS is to treat the underlying cause of the arrest. For example, cardiac dysrhythmias are treated with drugs and electric shock; a tension pneumothorax is treated by decompression of the pleural space; and, hypovolemia is treated with volume expansion.

Medical futility exists when a therapy or supportive care fails to provide any benefit to the patient. The act of a physician, serving as the patient's surrogate decision maker, withholding futile therapy without obtaining consent from the patient is gaining acceptance. Although futility can be an unclear term, its clinical application is more effective when considered as quantitative or qualitative.

Quantitative futility describes a clinical situation where the application of an intervention has a very low probability of producing a satisfactory outcome. This minimum threshold probability is controversial; and, consequently, best set on an individual case basis.

Qualitative futility describes the clinical situation where the outcome is survival but with an unsatisfactory quality of life, as defined by the patient. Excellent examples of qualitative futility include patients in a persistent vegetative state or patients dependent upon intensive medical care.

Patient autonomy - The patient or the patient's surrogate decision maker has the right to participate in all health care decisions, including the right to refuse unwanted life-saving care. In contrast, an important exception to patient autonomy is that physicians are not required to provide futile interventions that offer no benefit.

Patient outcome from cardiopulmonary arrest is a function of many factors, including etiology, initial rhythm of a cardiac arrest, timing of response, location, and duration of the arrest. One subgroup of patients with a relatively good outcome was witnessed out-of-hospital cardiac arrest cases in Seattle, USA, when the response time was less than four minutes and the initial rhythm was ventricular fibrillation (Cobb et al. 1999). 36% of these patients survived with favorable neurologic recovery. Unfortunately, more than 50% of these survivors died within one year. In contrast, survival for out-of-hospital arrest in other geographic regions where the initial rhythms were pulseless electrical activity and asystole have been reported as 2.5 and 0.3%, respectively (Stiell et al. 1999). Furthermore, if return of spontaneous circulation cannot be reestablished by emergency medical service (EMS) personnel in the out-of-hospital cardiac arrest patient, meaningful survival is exceedingly rare (Kellermann et al. 1993).

Most out-of-hospital resuscitation studies focus on primary cardiac arrests and exclude traumatic mechanisms. Arrest from a blunt mechanism is due to severe brain injury, high cervical spinal cord injury, cardiac or great vessel injury, or exsanguination from pelvic or abdominal injuries. The mortality of these patients is essentially 100%. It is undeniable that BLS and ACLS are ineffective therapies. Arrest from a penetrating mechanism is due chiefly to exsanguination and pericardial tamponade. The survival rates range from 0% to 20% and depend on the presence of signs of life, duration of the arrest, injuries, and skills of the trauma team. Of course, in these cases, the goals are to restore intravascular volume, evacuate the tamponade, and simultaneously control hemorrhage.

The outcome of in-hospital cardiopulmonary arrests is also sobering. Of 255 patients who suffered an in-hospital arrest in a noncritical care unit, 11% survived and were discharged from the hospital (Berger et al. 1994). These survivors spent on average 17 days in the ICU and 14 additional days on the hospital ward. Ultimately, only 4% survived to the end of the follow-up period (mean, 22 months). In an analysis of comorbidities, including age, cardiac disease was the only significant factor; the presence of cardiac disease was associated with reduced post-CPR survival.

An extensive prospective analysis of CPR was similarly examined in a surgical ICU (Smith et al. 1995). The incidence of cardiopulmonary arrest was 1.1% (55 of 5237 patients).

71% of these patients died within 24 hours. Only seven (13%) of these 55 patients survived to discharge. Other studies have found that survival from arrest occurring in the ICU was ~5–10%. Arrest in these ICU patients was usually the result of the final evolution of the underlying illness. This high mortality rate, therefore, is expected.

Cardiopulmonary arrest occurs from primary cardiac disease, loss of airway, cessation of spontaneous breathing, traumatic injury, and progression of critical illness. Patients surviving a cardiopulmonary arrest are transferred to the ICU. When organ failure develops or when neurologic function fails to improve during the first 72 hours following arrest, mortality rates are prohibitively high (Smith et al. 1995, Grubb et al. 1995). Therefore, factors adversely affecting prognosis include the following: absence of a correctable etiology, development of organ failure, and failure of neurologic improvement. When any of these factors are present, it is the physician's duty to discuss the patient's terminal condition with family members and to make recommendations on withdrawal of care.

Diagnosis

The diagnosis of cardiopulmonary arrest is straightforward. Patients are non-responsive and fail to have either spontaneous effective circulation as demonstrated by the absence of peripheral and central pulses or fail to have spontaneous breathing. Many etiologies are possible.

Therapy

In a patient who is resuscitated, BLS and ACLS protocols are typically followed. These treatments include endotrachial intubation, intravenous access for the delivery of fluids and drugs, closed chest compression, and direct current for cardioversion or defibrillation. Several trials have been conducted in attempt to improve outcome of CPR. No difference in outcome has been seen when high dose epinephrine was compared to standard dose epinephrine (grade A). Similarly, the use of sodium bicarbonate has been shown ineffective (grade B and C). Other studies have assessed the impact of closed chest compression effectiveness, of alternative techniques of closed chest compressions, and of the ability of the “code leader” to follow ACLS protocols (grade B). Although some statistically significant differences were found, it is our opinion that these modest differences were not clinically significant. Lastly, thrombolytic drugs, for the treatment of suspected pulmonary embolus, and vasopressin, as an alternative pressor to epinephrine, may offer benefit in selected cases (grade C). Interest in aggressive surgical treatment of cardiopulmonary arrest has been reported. Thoracotomy for performing open cardiac massage, clamping the descending aorta, decompressing the pericardium, treating pulmonary embolism, and controlling hemorrhage has been described. These are invariably heroic efforts in moribund patients. The only reasonable potential for survival is in the victim of penetrating thoracic injury and in the post-operative cardiac surgical patient (grade C). Lastly, cardiopulmonary bypass and extracorporeal life support techniques have been used in highly selected cases with limited success (grade C).

Since therapies for cardiopulmonary arrest are ineffective and often futile, it is critical to recognize their limitations. Arrest in the critically ill ICU patient should be anticipated and a “do not resuscitate” plan should be established. Discussions with family members should be forthright and compassionate. Additionally, the duration of CPR should be limited and placed in the context of the patient's underlying disease process. Failure to restore spontaneous circulation after 15–25 minutes of CPR indicates a non-salvageable patient (grade C).

With increasing application of patient autonomy, cardiopulmonary resuscitation in the ICU has been applied in several ways. Increased patient understanding of the outcomes of CPR has resulted in limited applications. Patients have requested that resuscitations be limited in scope and duration. One of the more common decisions by patients is the limitation of CPR to drug therapy only. The underlying assumption is that reversible problems may be effectively treated by drug therapy, whereas non-reversible problems would not be effectively treated regardless of which CPR therapies were applied. In this way, long and futile resuscitations are avoided, while reversible dysrhythmias are treated. The medical benefit to the patient of this approach is unproven; however, limiting the therapies of CPR due to patient preference is encouraged on the basis of patient autonomy.

In contrast to limiting treatment at the end of life, some patients wish that therapies be actively withdrawn in order to not prolong their death. When withdrawing life sustaining therapies - for example, mechanical ventilation, vasoactive drugs, nutrition, and fluids - it is best to individualize these decisions to each patient and family situation. Factors that influence the process of withdrawal of support include patient, family, and physician beliefs. For some patients, all care may be promptly withdrawn and death may rapidly follow. However, in patients that maintain a patent airway and breathing, death may not promptly follow removal of care (i.e., removal of endotracheal tube, discontinuing vasoactive drugs, discontinuing fluid administration, etc.). Human beliefs may then dictate that some therapy (e.g., fluid and nutrition) still be provided. When present, these beliefs should be honored. However, since these therapies will only prolong death, it seems most appropriate to not provide them. We would also advocate appropriate sedation and pain management. These patients dying over days should be transferred to hospice centers whenever possible.

Additionally, family visitation at the end of life can vary. Of course, withdrawal of care may be delayed to allow family members travel time to arrive to see the patient prior to death. Some family members may want to be present when the patient dies. This desire should be honored. Discussions with families should recognize unique circumstances. Families should not be put in a position where they feel responsible for their loved one's death. It is emphasized that the illness is causing the death and that the family is preventing a prolonging of death. Finally, once the decision to withdraw support has been made, most families prefer the process to be prompt. Other families request incremental therapy withdrawal.

Patients and families are also encouraged to have support from clergy or social workers while making end of life decisions. Such individuals can also reassure physicians and nurses that the family is acting in the best interests of the patient. These professionals are particularly important when there is no family member with clear legal authority to make decisions on the patient's behalf and when family members have different beliefs. During withdrawal of support, narcotics or sedatives should be administered liberally to dying patients. These agents ensure patient comfort during death. Families are reassured that their loved ones are not suffering. Patients, families, physicians, and nurses should not fear administering these drugs because they may cause significant respiratory depression.

Conclusion

Cardiopulmonary arrest reflects the end point in the progression of a severe underlying derangement. Expectation for patient survival is possible if the underlying cause can be promptly identified and corrected. In out-of-hospital arrest from ventricular fibrillation, this principle translates to an EMS response time of within four minutes. In contrast, cardiac arrest occurring in the ICU most commonly reflects the natural history of the patient's illness, resulting in the patient's death. The application of therapies to this group of patients results in prolonging the patient's death. CPR should be withheld in this group on the basis of futility. It is critical that this type of patient be distinguished from a patient with a reversible cause of arrest. It is somewhat ironic that CPR is so widely employed while its efficacy is so poor. As long as human nature remains unchanged and outcomes from CPR remain poor, it is likely that CPR will continue to be over-utilized. Applying evidence based principles to future studies of out-of-hospital cardiac arrests will hopefully result in more effective strategies. Evidence based principles applied to investigations of new therapies for arrests of ICU patients is likely to be limited by variations of patient population, factors such as ethnicity and religion, and variations in judgement, dexterity, skill, and ethical beliefs of intensivists.

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