Background.
Pleural effusion (PE) is a common complication after cardiac surgery and is associated with postoperative heart failure and adverse outcomes. Lung ultrasound (LU) has been shown to be more accurate than chest x-ray (CXR) in the diagnosis and evaluation of PE. Other advantages include bedside applicability, no radiation exposure, and low cost. However, the use of LU in the rehabilitation setting of post-cardiac surgery patients is still limited.
Objective.
To determine the extent of the use of LU compared with CXR in the evaluation of PE in post-cardiac surgery follow-up (FUP) in an Italian rehabilitation hospital.
Methods.
Fifty consecutive patients (pts) (mean age: 67+9 years, 28 males, 22 females) admitted to our rehabilitation center 9+2 days after cardiac surgery (25 valve surgery, 16 coronary artery bypass graft (CABG), 6 valve surgery + CABG, 3 pulmonary endarterectomy) were included in the study and underwent baseline LU + CXR (time T0). Based on the clinical condition of each patient, the treating cardiologist decided whether to perform follow-up assessment by LU alone (GROUP1, less severe patients) or by CXR + LU (GROUP2, more severe patients) (time T1). The severity of PE was graded by the radiologist/sonographer using a 4-point scale (0=none, 1=mild, 2=moderate, 3=severe PE). The presence of pulmonary atelectasis on LUS was reported to the physician. Patients performed a 6MWT at baseline and at discharge.
Results.
Figure 1 shows the study flow chart and Table 1 shows the main patient characteristics in both Groups. Table 2 shows the comparison between the two methods of PE assessment. At T0, the severity of PE as assessed by LU was similar in both groups and was underestimated by CXR. Of the 18 patients who underwent CXR+LU at T1, 9 (50%) required CXR evaluation for the following pulmonary complications: 5 suspected pneumonia (2 confirmed), 2 congestive heart failure, 1 hypoxemia, 1 parenchymal nodule. Medical therapy and the percentage of patients with bilateral atelectasis were similar in the two groups.
Conclusions.
Our data show that CXR underestimate the severity of PE. CXR is still unnecessarily ordered by the treating cardiologist in approximately one third of patients with moderate/severe PE and no other pulmonary complications.