Tachypnea in a Patient After Hip Repair Surgery

Case Study

Rapid response event was activated by bedside nurse for a patient with tachypnea and tachycardia (heart rate of 180 beats per min). On arrival of the rapid response team, the patient was quickly assessed along with a brief history from the bedside nurse. The patient was a 69-year-old male with no known comorbidities who was admitted to the hospital for the past five days after suffering a ground-level fall one week ago and a left femoral neck fracture. He underwent hip repair surgery four days ago and was doing fine with rehabilitation until the morning of this event when the nurse saw his elevated heart rate on routine vital monitoring.

Vital Signs

Temperature: 98.4 °F, axillary
Blood Pressure: 110/78 mm of Hg
Heart Rate: 160 beats per min, sinus tachycardia on telemetry monitor ( Fig. 19.1 )

Fig. 19.1

Cardiac rhythm strip showing sinus tachycardia at a rate of ~180 beats per min, with ST-segment depression.
Respiratory Rate: 44 breaths per min
Oxygen Saturation: 82% on room air

Focused Physical Examination

A quick exam showed a middle-aged man with moderate respiratory distress, who was tachypneic and sitting up in bed. His chest auscultation was not significant for wheezing or crackles, and his breath sounds were equal bilaterally. His heart sounds were difficult to comprehend because of severe tachycardia. He denied any chest pain or pain anywhere else in the body.

Interventions

The patient was supplied with supplementary oxygen through a nasal cannula. A stat troponin, lactate level, complete blood count (CBC), arterial blood gas, and portable chest X-ray were ordered. Cardiac monitor pads were attached to the patient’s chest. A 12-lead electrocardiogram (EKG) showed sinus tachycardia. Chest X-ray did not show any acute cardiopulmonary disease. Arterial blood gas showed a pH of 7.52, paO ₂ of 50, pCO ₂ of 30, and SPO ₂ of 84%. At this time it was determined that the most likely (EKG) differential diagnosis for this event was an acute pulmonary embolism (PE). The patient was prophylactically started on a therapeutic heparin drip and sent down to the radiology department for computed tomography (CT) of the chest for the evaluation of PE. CT scan showed a large saddle embolus with signs of right ventricular (RV) strain. The patient was transferred to the intensive care unit (ICU) directly from the radiology department to monitor his hemodynamic status closely.

Final Diagnosis

Acute submassive PE.

Alternative Diagnosis: Pulmonary fat embolism (can be primary diagnosis in a similar patient who did not get the fracture repaired); it can be differentiated from a PE on CT.

Pulmonary Embolism

PE is one of those clandestine conditions that occur in patients with decreased mobility and those with other risk factors that might provoke thrombosis. Our patient is one such prime example where he was immobile after suffering a fall and having a hip fracture. Although his fracture was repaired, his pain and post-operative status impaired his mobility level. Historical data suggests that PE and deep vein thrombosis (DVT) are most common in patients five to seven days after hip repair surgery, and to prevent this, almost all these patients are given high-dose prophylactic anticoagulation from post-operative day one. Enoxaparin is the preferred drug for this indication and although it reduces the incidence of PE, some patients still develop thrombosis post-operatively.

Definition

Pulmonary embolism is defined as a sudden blockage in one of the pulmonary arteries. It is usually the result of DVT in one of the veins in extremities which gets dislodged and travels up toward the heart, crosses the right heart, and gets stuck in the pulmonary vasculature.

PE can be classified as massive, submassive, and low-risk PE ( Table 19.1 ). Identifying different clinical signs and symptoms associated with PE is crucial for the prompt start of appropriate management and helping rule out other causes of hypoxia ( Table 19.2 ).

Table 19.1

Classification of pulmonary embolism per American Heart Association

Massive PE	Submassive PE	Low Risk PE
Acute PE with sustained hypotension (SBP <90 mmHg) for more than 15 min or requiring inotropic support	Acute PE with SBP >90 mmHg and either: a) RV dysfunction (computed tomography, BNP/pro-BNP, electrocardiogram changes) or b) myocardial necrosis (elevated troponins)	Acute PE with an absence of systolic hypotension, right ventricular dysfunction, and myocardial necrosis
High mortality – 25%-65%	Low mortality – 3%	Lowest mortality –<1%
Also known as – PE with hypotension – High risk PE	Also known as – PE without hypotension – Intermediate risk PE	Known as low risk PE for all classifications
Therapy: systemic anticoagulation +/− thrombolysis	Therapy: systemic anticoagulation	Therapy: systemic anticoagulation. Some clinicians will decide not to anticoagulate patients with sub-segmental PE, as per the latest evidence
Setting: intensive care unit	Setting: better to monitor in an intensive care unit	Setting: can be monitored on a medical ward