Approach to postoperative respiratory distress: Clinical sciences

Postoperative respiratory distress can occur after any operation due to issues with the airway and lung parenchyma itself, or from respiratory muscle dysfunction. It can be life-threatening if left untreated. Although there are many different causes, the life-threatening conditions you must first identify are tension pneumothorax, acute respiratory distress syndrome or ARDS, upper airway obstruction, and pulmonary embolism. Other urgent causes include atelectasis, pneumonia, pleural effusion, pulmonary edema, aspiration pneumonitis, and bronchospasm. Keep in mind that any cause of postoperative respiratory distress can become life-threatening if not managed appropriately, and any of these complications require immediate intervention.

Your first step in assessing a patient with postoperative respiratory distress is to evaluate their ABCDE. If you determine that the patient is unstable, initiate acute management immediately. First, stabilize the airway. Keep in mind that some patients might require intubation or even a surgical airway like a cricothyroidotomy. Next, provide supplemental oxygen and support with mechanical ventilation, obtain IV access, and monitor their vitals. Once these important steps are done, you should perform a focused history and physical exam to quickly assess for life-threatening conditions.

Here’s a clinical pearl! Regardless of the cause, many patients will have similar signs and symptoms, such as dyspnea, tachypnea, increased work of breathing, and hypoxemia. So if you see any of these in a postoperative patient, make sure to act quickly!

Alright, let’s first talk about tension pneumothorax. If the patient required high positive airway pressure during surgery or a central line placement, or if they had a difficult airway, and on the exam you find absent lung sounds, unequal breath sounds, hyperresonance to percussion, and tracheal deviation, you can make your diagnosis of tension pneumothorax. Remember, tension pneumothorax is a clinical diagnosis, so you should go directly to treatment such as needle decompression or tube thoracostomy.

Okay, let's go back to history and physical exam to go over ARDS. History might reveal a severe inflammatory state like sepsis or a high-risk operation such as oncologic resection for cancer. The physical exam typically reveals crackles and severe hypoxemia. In this case, you should think about ARDS. Your next step is to obtain an arterial blood gas, or ABG, and a chest x-ray. The ABG will show hypoxemia, and either a respiratory acidosis or alkalosis, depending on how sick the patient is. The chest x-ray will show severe bilateral lung infiltrates. These findings indicate ARDS, so you’ll need to provide positive pressure by intubating the patient, which recruits more alveoli and improves gas exchange.

Next, let’s go over upper airway obstruction. Your patient may have a history of difficult intubation, obesity, obstructive sleep apnea, anaphylaxis, or postoperative soft tissue swelling or hematoma. Also, surgeries involving the thyroid and parathyroid can cause damage to the recurrent laryngeal nerve and cause vocal cord paralysis and laryngospasm. Here, you need to examine their neck and oropharynx quickly. If you see angioedema of the tongue, oropharyngeal swelling, and face or neck swelling, and hear stridor due to laryngeal swelling, you can make your diagnosis of upper airway obstruction.

Let’s move on to our last life-threatening condition, pulmonary embolism. Your patient may have a history of a deep venous thrombosis, or DVT, or a hypercoagulable state, which can be due to an underlying condition like malignancy. Physical exam will show signs of respiratory collapse, including hypoxemia and hyperventilation, due to V/Q mismatch. You may also see hemodynamic collapse due to pulmonary hypertension, resulting in symptoms like cyanosis, tachycardia, arrhythmias, and, if severe enough, hypotension. If any of these findings are present, consider pulmonary embolism. Your next step is to order a CT angiogram of the chest to visualize any filling defects in the pulmonary arteries, which will confirm your diagnosis.

Alright, now let’s talk about stable patients. Even if on initial assessment the patient is stable, you should always move to quickly determine the etiology of postoperative respiratory distress, as even the urgent causes can progress to life-threatening conditions if not managed appropriately.

Your first step in assessing a stable patient is to obtain a focused history and physical exam. Additionally, consider an ABG, which is not always needed to make your diagnosis, but may help this workup. You might also consider other labs, like a CBC, depending on the situation. Finally, in all patients, obtain a chest x-ray.

The most common cause of postoperative respiratory distress is atelectasis. Let’s say you have a recent postoperative patient who reports a cough with or without sputum, and dyspnea. On exam, you’ll see decreased chest expansion and shallow breathing, as well as decreased breath sounds and crackles on auscultation. ABG will often show hypoxemia, while the chest x-ray will show increased opacification, displacement of lung fissures, narrowing of intercostal spaces, or elevation of hemidiaphragm on the affected side. If you see these findings, you can diagnose atelectasis.