2.2 Cardiogenic & Obstructive Shock: Recognition, Tamponade, PE & Tension Pneumothorax

Cardiogenic & Obstructive Shock: Recognition, Tamponade, PE & Tension Pneumothorax

Clinical core: Recognize hypoperfusion, establish whether cardiac dysfunction or a mechanical barrier is contributing, and treat the cause while supporting circulation. A child can have cardiogenic shock with preserved blood pressure or without obvious congestion.

Recognize impaired pump function and assess congestion

The 2026 AHA pediatric cardiogenic shock statement frames cardiogenic shock as known or suspected cardiac dysfunction with clinical or biochemical evidence of tissue hypoperfusion. Examine pulses, capillary refill, skin temperature, mentation, and urine output. Follow lactate and renal and hepatic function as appropriate. Tachycardia, cool extremities, and a narrow pulse pressure can reflect low stroke volume, even before hypotension develops.

Consider myocarditis, cardiomyopathy, postoperative ventricular dysfunction, transplant rejection, or sustained tachyarrhythmia or bradyarrhythmia. Structural disease can produce the same low-flow presentation. In an infant, consider ductal-dependent systemic circulation or an anomalous left coronary artery from the pulmonary artery. Obtain an ECG and urgent echocardiography with pediatric cardiology when available. Focused ultrasound by a trained clinician can rapidly identify gross ventricular dysfunction or an effusion. Formal echocardiography evaluates anatomy and potential causes.

Match fluid, inotropes, and escalation to the physiology

If congestion is apparent, avoid routine large crystalloid boluses. If there is evidence of inadequate preload despite myocardial dysfunction, give small amounts with frequent reassessment. The AHA statement describes $5–7.5\text{ mL/kg}$ at a time over longer intervals such as 2–4 hours as one option when volume is needed and the patient can tolerate that approach. A hypotensive child with poor perfusion needs prompt hemodynamic support and expert involvement while the team establishes the cause. A fluid challenge must never delay that support. Reassess clinical perfusion, breathing, and ventricular filling after any fluid. In a congested child with adequate pressure, consider decongestion with the cardiac team.

If perfusion worsens, involve a pediatric cardiac intensive care and mechanical support team early. VA-ECMO can provide temporary circulatory and gas-exchange support. A ventricular assist device supports circulation and may serve as a bridge to recovery or transplant in selected patients. Selection depends on the cause, ventricular involvement, respiratory failure, and clinical trajectory.

Worked distinction: An infant with cool skin and delayed refill after several days of viral symptoms may initially resemble a child with dehydration or infection. New crackles, an enlarged liver, and a gallop with persistent hypotension raise concern for pump failure. Start appropriate inotropic support and obtain urgent cardiac assessment while limiting further fluid. An infant with substantial gastrointestinal losses, clear lungs, and a clear volume-loss history needs a different initial fluid strategy.

Relieve tamponade or tension pneumothorax

In cardiac tamponade, pressure from fluid or blood in the pericardial space limits cardiac filling and lowers stroke volume. Consider it after cardiac surgery, penetrating injury, pericarditis, or central catheter complications. Beck's triad is hypotension, muffled heart sounds, and jugular venous distention. The triad can be incomplete. An inspiratory systolic pressure drop greater than 10 mmHg during spontaneous breathing is pulsus paradoxus and can support the diagnosis. Low voltage or electrical alternans can occur with a large effusion.

Use urgent bedside echocardiography to look for pericardial fluid and impaired filling, such as right-sided chamber collapse. An effusion alone does not establish tamponade. An unstable child requires prompt drainage by an experienced team. When percutaneous drainage is appropriate, use ultrasound to select the safest fluid pocket and needle path. A subxiphoid approach is one option. Postoperative bleeding, traumatic hemopericardium, or purulent fluid can require surgical drainage or repair. Temporary volume support can help selected patients while drainage is arranged. Positive-pressure ventilation may further impair venous return, so coordinate the airway and drainage plan if ventilatory support is necessary. Pericardial guideline

In tension pneumothorax, rising pleural pressure compresses the lung and impairs venous return. Suspect it with sudden respiratory compromise, unilateral reduced air entry, and hypotension, especially after trauma or during positive-pressure ventilation. Tracheal deviation may occur late. Treat an unstable child with a convincing clinical presentation immediately, without waiting for radiography.

Use the local pediatric trauma technique and equipment. Needle decompression sites used in pediatric protocols include the second intercostal space at the midclavicular line or the fourth or fifth intercostal space at the anterior axillary line. Enter just above the rib at the protocol-selected site. In a trauma setting, trained clinicians may perform finger thoracostomy as appropriate. Reassess immediately for improvement or recurrent tension and proceed to definitive chest drainage. Pediatric resuscitation guidance

Recognize and treat high-risk pulmonary embolism

A pulmonary embolus can abruptly increase right ventricular afterload, reduce left ventricular filling, and cause obstructive shock. Consider it with acute dyspnea, pleuritic pain, unexplained hypoxemia, or collapse. Risk factors include an indwelling central line, active nephrotic syndrome, malignancy or asparaginase exposure, immobility, and thrombophilia. A line is a risk factor even when the source of a particular embolus is unknown.

CT pulmonary angiography can confirm PE when feasible. In an unstable child, initiate resuscitation and consult pediatric critical care, hematology, and the PE response team where available. Bedside echocardiography can identify acute right ventricular dilation or dysfunction and help evaluate other causes of shock when transfer for CT is unsafe. Right ventricular strain and ECG findings such as sinus tachycardia or an $S_1Q_3T_3$ pattern are supportive in context and cannot confirm or exclude PE alone.

The ASH/ISTH pediatric VTE guideline bases thrombolysis on hemodynamic compromise, such as sustained hypotension or shock. For that group it conditionally suggests thrombolysis followed by anticoagulation, with very low certainty. For right ventricular dysfunction without hemodynamic compromise, it conditionally suggests anticoagulation alone. The presence of a saddle embolus does not replace this assessment. Use the local pediatric regimen and assess bleeding risk. Systemic alteplase is an option when appropriate. If systemic lysis is unsafe or fails, consult the response team promptly about catheter-based or surgical reperfusion.