Sympathetic Crashing Acute Pulmonary Edema (SCAPE): An Overview

Introduction

Sympathetic crashing acute pulmonary edema (SCAPE) is also called flash pulmonary edema, crashing pulmonary edema, severe acute pulmonary edema, or acute decompensated heart failure. Excess fluid in the lungs leads to a condition called pulmonary edema. Accumulation of the fluid within the air sacs makes it difficult for the person to breathe comfortably. Pulmonary edema can be of different types based on the causes. Pulmonary edema may be due to increased cardiac pressure or other factors unrelated to the heart. It can be acute (sudden onset) or chronic (slow onset). SCAPE is an extreme type of acute pulmonary edema.

What Is Sympathetic Crashing Acute Pulmonary Edema (SCAPE)?

Critical patients admitted to the emergency department may experience difficulty breathing or dyspnea. It may be due to acute heart failure syndrome (AHFS). AHFS leads to a sudden or gradual development of the signs of heart failure. Patients with SCAPE or flash pulmonary edema may have severe acute heart failure syndrome. It is a syndrome that develops rapidly and is life-threatening.

What Are the Causes of Sympathetic Crashing Acute Pulmonary Edema?

The following underlying causes can lead to sympathetic acute pulmonary edema:

• Congestive Heart Failure: Congestive heart failure is a chronic condition in which the heart cannot pump enough blood to supply the entire body. This leads to the backing up of blood and the accumulation of fluids, leading to swelling.

• Toxic Chemical Inhalation: Oxides of nitrogen, like nitric oxide and nitrogen dioxide, causes damage to the lungs. These gases, on inhalation, get converted to nitric acid and nitrous acid, which damages the respiratory cells. It also leads to the generation of free radicals that further damages the system. These gases irritate, even when inhaled in a lower concentration.

• Pneumonia: Pneumonia is a lung infection caused by bacteria or viruses leading to the accumulation of fluid and pus in the alveoli.

• Medications: Certain medications may cause allergic reactions, bleeding in the alveoli, inflammation or swelling within the respiratory components, lung tissue damage, fluid buildup, etc. Sulfa drugs and chemotherapy drugs are some examples.

What Are the Symptoms of Sympathetic Crashing Acute Pulmonary Edema?

The following are the clinical features of SCAPE:

• The patient may experience dyspnea or shortness of breath, progressing to severe pulmonary edema. They may wheeze.

• Acute respiratory distress syndrome (ARDS) may develop due to fluid buildup in the alveoli, leading to decreased oxygen levels in the bloodstream and reduced oxygen supply to the organs.

• Patients may get restless.

• The patients may sweat excessively, leading to diaphoresis.

• The patient might feel anxious.

• The skin becomes cold and highly moist.

• The patient may experience pain in the chest and adjacent areas.

• The mucous discharge from the throat or lungs may have an altered color, like pinkish or bloody.

• Lack of oxygen in the tissue level leads to a condition called hypoxia.

• The patient's heart rate may rise above 100 beats per minute, causing tachycardia.

• The blood pressure increases to more than the normal range, making the patient hypertensive.

• The patient may get dizzy.

• The patient may cough productively with bloody and frothy sputum.

What Are the Risk Factors Of SCAPE?

Certain underlying medical conditions or lifestyle factors may put a person at risk for developing a flash pulmonary edema. The following are the risk factors:

• Hypertension (increased blood pressure).

• Diabetes (high blood sugar level).

• Unhealthy lifestyle practices like chronic alcoholism.

• Preexisting heart disaeses.

• Sleep apnoea.

How to Manage Sympathetic Crashing Acute Pulmonary Edema?

Patients with flash pulmonary edema will be admitted to an intensive care unit (ICU) to initiate emergency treatments to prevent morbidity and mortality. Management steps include the following:

• Invasive Mechanical Ventilation: The patient will be given high-dose nitroglycerine and noninvasive ventilation to manage SCAPE. Some patients may require intubation. During this procedure, an intubation tube will be inserted into the nose or mouth of the patient. The tube will be connected to an oxygen-delivering machine. This keeps the trachea open for the passage of air.

• Noninvasive Ventilation: Bilevel positive airway pressure (BiPAP or BPAP) is a ventilator that helps the patient to breathe. It is a concise device with a tube connected to a mask. In noninvasive ventilation, the patient has to wear a mask on the mouth and nose. The BiPAP machine pushes air into the lungs under pressure. Continuous positive airway pressure (CPAP) machines will also be used for noninvasive ventilation. CPAP machines use mild pressure to keep the patient breathing.

• Nitrates: Depending on the dosage given, nitrates cause venodialtion or arteriodilation. It also reduces blood pressure. It may be given sublingually or through intravenous (IV) routes. Nitroglycerine and Nitroprusside are some blood pressure-controlling drugs used to manage SCAPE.

• Diuretics: Diuretics or water pills are medicines that help the body get rid of excess fluid and salt or sodium. Reducing excess fluid accumulation leads to a decrease in the pressure caused by the accumulation in the lungs or the heart, reducing the symptoms of flash pulmonary edema. Furosemide is an example of diuretics used for this purpose.

• Morphine: Morphine is an opiate used to relieve moderate to severe pain. It is also used to treat sympathetic crashing acute pulmonary edema. Morphine cause relief by dilating the vein and reducing the preload. Pain and anxiety may also get relieved using morphine. But, the medication can cause potential side effects which outweigh the benefits. Therefore it is currently not prescribed by the doctors.

• Inotropic Agents: Inotropic agents or inotropes are medications that control the power by which the heart muscles contract. It keeps the heart pumping and also regulates the blood pressure. It is usually given through the intravenous (IV) route.

Conclusion

Sympathetic crashing acute pulmonary edema or SCAPE, is a life-threatening condition that requires emergency department admission and treatment. A person should seek immediate medical help in case of sudden dyspnea, suffocation, coughs with bloody phlegm, wheezing while breathing, severe sweating, or feeling dizzy, lightheaded, or extremely weak. These symptoms may be due to pulmonary edema and require immediate treatment. Heart failure may be the underlying cause of these symptoms, and it develops unnoticed.