Pulmonary embolism: recognition and first response

A pulmonary embolism is a thrombus, most often carried up from a deep vein of the leg or pelvis, that lodges in the pulmonary circulation and blocks blood flow to lung that is still being ventilated, so the patient becomes hypoxaemic and the right ventricle is suddenly made to pump against an obstruction it cannot overcome -- and because it arrives without warning and announces itself through signs that belong to commoner and more innocent things, the nurse suspects it from the suddenness and from the patient's risk profile rather than waiting for a complete picture: immobility, recent surgery, trauma or a fracture, a previous clot, cancer and its treatment, pregnancy and the period after it, oestrogen-containing hormones, obesity, smoking, heart failure, a central venous catheter, prolonged travel and inherited clotting disorders; the presentation is most often sudden breathlessness and a rising respiratory rate with a fast heart, and may carry pleuritic chest pain, a cough, blood in the sputum, sweating, restlessness, anxiety and a sense that something is badly wrong, fainting or near-fainting, and in the large embolism a falling blood pressure, cyanosis, distended neck veins and a cold clammy skin -- while nothing about the patient rules it out: the chest may sound clear and the chest film look normal, the oximeter may not yet have fallen and can read normally when perfusion or the probe are the problem, the legs are frequently silent because the vein that produced the clot gives no symptoms, and the diagnosis is not made at the bedside at all but rests on clinical probability assessed against a validated rule, a D-dimer where that probability is not high, and imaging of the pulmonary arteries; so the nurse's response is to treat the suspicion as the emergency it is -- staying with the patient and sending someone else for help and for the rapid-response or resuscitation team rather than leaving to fetch anything, sitting the patient upright unless the blood pressure will not allow it, giving high-concentration oxygen, putting the patient on continuous monitoring of rate, rhythm, blood pressure and saturation, securing intravenous access, recording an electrocardiogram, keeping the patient at rest and not walking, straining or massaging a painful calf, and preparing for the imaging and the anticoagulation the team will order, which is begun on a strong suspicion rather than held until the scan confirms it unless bleeding forbids it -- and then keeps watching for the deterioration that is the real danger: a blood pressure that is falling, a heart rate and respiratory rate that are climbing, a saturation that will not come up on oxygen, neck veins that are filling, a patient who is becoming drowsy or confused, all of them the failing right ventricle producing obstructive shock, which can end in cardiac arrest that is sometimes the first sign anyone sees.