Obstructive shock

Question 1

Obstructive Shock — Identification & Emergency Management

Answer 1

=>Obstructive shock causes acute hypotension with impaired venous return or impaired cardiac filling. Diagnosis requires rapid, structured evaluation for:
* Tension Pneumo
* Cardiac Tamponade
* Abdominal compartment
* DHI

Question 2

Abdominal Compartment Syndrome

Answer 2

=>Caused by
* ↑ Intraluminal pressure eg- bowel obstruction
* ↑Extraluminal pressure eg- capillary leak, or fluid overload.
* ↓ abdominal wall compliance- eg- burns/ obesity

->Suspect when intra-abdominal pressure >25 mmHg.

->Consequences: organ failure eg- impaired cardiac, pulmonary, renal and CNS function.

->Diagnosis: bladder pressure measurement.
* Treat according to abdominal compartment syndrome guidelines (decompression etc.).

Question 3

Auto-PEEP (Dynamic Hyperinflation)

Answer 3

• Originates in the thorax (obstructive shock due to ventilatory mechanics).
• Failure to empty adequately before next breath → ↑ intrathoracic pressure → ↓ venous return → ↓ cardiac output.
• Causes: short expiratory times, high MV, obstructive lung disease.
• Hallmark: persistent low end-expiratory flow on ventilator waveform.

=>Management:
* Immediate disconnect from ventilator (manual decompression).
* ↓ Respiratory rate and/or ↓ I:E ratio → ↑ expiratory time.

Question 4

Tension Pneumothorax

Answer 4

• Air enters pleural space without escape → ↑ intrapleural pressure → mediastinal shift → ↓ venous return.
• Signs: unilateral breath sounds, shock.
• Ultrasound can aid diagnosis.
• Immediate needle decompression → chest tube.

Question 5

Cardiac Tamponade

Answer 5

• Extracardiac fluid compresses heart → ↓ ventricular filling → ↓ stroke volume.
• Highly compliant right ventricle affected first.
• Causes: bloody or exudative effusion, RVAD complications, mediastinal fluid.
• Signs: hypotension, tachycardia, pulsus paradoxus (>10 mmHg), electrical alternans.
• Bedside echo = essential (pericardial effusion, chamber collapse).
• Urgent pericardiocentesis required.

Tamponade- >10% or 12mm hg ⬇️ in systemic BP during inspiration