RESULTS

A total of 375 studies were retrieved through our search, and 80 duplicates were removed. The titles and abstracts of the remaining 295 studies were screened to identify potentially eligible 22 studies. After the full-text screening, 18 studies were included in the systematic review. Eleven studies were conducted in the United States of America1–3,7,10–16, four studies in the United Kingdom17–20, one in the Netherlands5, one in Germany21and one in Iran6(Table 1). No other studies were identified through manual screening of references of the included studies and relevant reviews. PRISMA flow diagram is demonstrated in Figure 1. Adult patients refer to patients at least 18 years of age, and paediatric patients refer to patients under the age of 18 in the studies. Re-intervention is defined as the re-insertion of a chest drain.

Cardiac surgery adult patients

One simple randomised trial6, three prospective cohort studies5,11,19and one retrospective cohort study18evaluated the efficacy of routine chest X-rays constituting a total of 2,080 adult patients undergoing cardiac surgery procedures, which includes coronary artery bypass grafting (CABG), valve surgery and atrial septal defect repair, either as isolated procedures or in combination. The mean duration of chest drain before removal is 1.4-1.8 days11,18,19, and a routine chest X-ray is obtained within 3-4 hours after the removal.6,19
If a chest X-ray is obtained after the removal, the incidence of pneumothorax ranges from 1.3-9.3% with up to 1.3% of patients developing respiratory symptoms or haemodynamic changes and re-intervention was required in 0.5-1.3% of the patients.5,6,11,18,19If no routine chest X-ray was performed after the drain removal, 5.0-11.8% of the patients developed respiratory symptoms or haemodynamic changes, of which 0.7-2.5% would require re-intervention.6,18

Cardiac surgery paediatric patients

Two prospective cohort studies10,20and two retrospective cohort studies7,14have examined the incidence of pneumothorax and the efficacy of chest X-rays after the chest drain removal. It includes a total of 12,171 paediatric patients undergoing congenital cardiac surgery operations. The mean age of the patients ranges from 0.2-2.7 years. The mean duration of chest drain varies from 1-6.4 days after the procedure, and a chest X-ray is performed within 2-6 hours after the removal of the drain.7,10,14,20
The incidence of pneumothorax after chest drain removal is 0.21% in a study with 11,651 patients7and goes as high as 13.6% in other studies.10,14,20Clinical symptoms developed in 0.1-1.87% of the patients, and 0.1-1.6% of patients would eventually undergo re-intervention for the pneumothorax.7,14

Thoracic surgery adult patients

Three prospective studies15,17,21and two retrospective studies1,2including 921 patients explored the effectiveness of routine chest X-rays in adult patients undergoing thoracic surgical procedures, which include both video-assisted thoracoscopy (VATS) and open surgery. The patients have a mean age of 60-64 years in the studies and had the chest drains for an average duration ranging from 1-4 days. A chest X-ray is usually performed 2-4 hours after the removal of the chest drain.1
The incidence of pneumothorax on the chest X-ray after removal of the drain varies greatly from 4 to 48%.1,2,15,17,21Nonetheless, only up to 0.5% of patients need a subsequent intervention after the positive radiographic findings.1,2,17The incidence of pneumothorax in asymptomatic patients is approximately 32.8%, but none of the patients required re-intervention. They only had clinical observation and repeated the chest X-rays.1

Thoracic surgery paediatric patients

Four retrospective studies with a total of 708 paediatric patients investigated the necessity of performing routine chest X-rays after the removal of chest drains.3,12,13,16The mean age of patients in the studies ranges from 7.5 to 9.4 years. The patients underwent various thoracic surgical procedures including VATS and open surgeries. The average length of the chest drain is 3.7-7.2 days before removal, and the chest X-rays are obtained within 2-6 hours after the removal of the drain.
In the post-drain removal chest X-rays, the incidence of pneumothorax is 3.1-3.9%3,12with a re-intervention rate is 0.7-1.7%.12,13,16Clinical symptoms were present in all patients who required re-intervention. In asymptomatic patients, the incidence of pneumothorax is 1.8%13, of which 0.4-0.9% of the asymptomatic patients would undergo further re-intervention.13,16

Bedside ultrasound versus chest X-ray after removal of chest drain

There are two prospective observational studies with combined 173 patients, which evaluated the role of bedside ultrasound in comparison to using chest X-ray after removal of a chest drain to detect pneumothorax, predominantly in the thoracic adult surgical population.15,21The overall sensitivity of the bedside ultrasound is 32%, however, the sensitivity is increased to 100% in detecting pneumothoraces of 3 cm or larger, and the specificity is 85%.21There is a strong association between ultrasound and chest X-ray with a therapeutic agreement of 97%.21There is perfect agreement between the two methods with a 𝛋 statistics value of 1.000.15