Prospective trial evaluating sonography after thoracic surgery in postoperative care and decision making

Thoracic Ultrasound as an Alternative to Chest X-ray in Thoracic Surgery Patients: A Single-Center Experience

Background/Objectives: Chest X-ray (CXR) is currently the most used investigation for clinical follow-up after major noncardiac thoracic surgery. This study explores the use of lung ultrasound (LUS) as an alternative to CXR in the postoperative management of patients who undergo major thoracic procedures. Methods: The patients in our cohort were monitored with both a CXR and a lung ultrasonography after surgery and the day after chest drain removal. The LUS was performed by a member of the medical staff of our unit who was blinded to both the images and the radiologist's report of the CXR. Findings were compared between the two methods. Results: In the immediate postoperative evaluation, 280 patients were compared, finding general agreement between the two procedures at 84% (kappa statistic, 0.603). The LUS showed a sensibility of 84.1%, a specificity of 84.3%, a positive predictive value (PPV) of 60.9%, and a negative predictive value (NPV) of 94.8%. We evaluated 219 out of 280 patients in the postdrainage-removal setting due to technical issues. Concordance between the methods in the postdrainage-removal setting was 89% (kappa statistic, 0.761) with the LUS demonstrating an 82.2% sensibility, a 93.2% specificity, a PPV of 85.7%, and an NPV of 91.3%. Conclusions: The results of this study showed a substantial agreement between LUS and CXR, suggesting that the LUS could reduce the number of X rays in certain conditions. The high NPV allows for the exclusion of PNX and pleural effusion without the need to expose patients to radiation. Discrepancies were noted in cases of mild pneumothorax or modest pleural effusion, without altering the clinical approach.

Lung Ultrasound Reduces Chest X-rays in Postoperative Care after Thoracic Surgery: Is There a Role for Artificial Intelligence?-Systematic Review

BACKGROUND

Chest X-ray (CXR) remains the standard imaging modality in postoperative care after non-cardiac thoracic surgery. Lung ultrasound (LUS) showed promising results in CXR reduction. The aim of this review was to identify areas where the evaluation of LUS videos by artificial intelligence could improve the implementation of LUS in thoracic surgery.

METHODS

A literature review of the replacement of the CXR by LUS after thoracic surgery and the evaluation of LUS videos by artificial intelligence after thoracic surgery was conducted in Medline.

RESULTS

Here, eight out of 10 reviewed studies evaluating LUS in CXR reduction showed that LUS can reduce CXR without a negative impact on patient outcome after thoracic surgery. No studies on the evaluation of LUS signs by artificial intelligence after thoracic surgery were found.

CONCLUSION

LUS can reduce CXR after thoracic surgery. We presume that artificial intelligence could help increase the LUS accuracy, objectify the LUS findings, shorten the learning curve, and decrease the number of inconclusive results. To confirm this assumption, clinical trials are necessary. This research is funded by the Slovak Research and Development Agency, grant number APVV 20-0232.

Ultrasonography can replace chest X-rays in the postoperative care of thoracic surgical patients

Objectives

Lung ultrasound accurately identifies pulmonary and pleural pathologies. Presently it has not been accepted as a routine examination in the postoperative follow-up of thoracic surgical patients. The present study aimed to compare thoracic ultrasonography with chest X-ray for detecting and clinical relevance of pneumothorax, pleural effusion, and lung consolidation and determine whether ultrasonography could replace chest X-ray as the standard examination after surgery.

Methods

In this blinded, prospective, single-center study, lung ultrasound images were obtained within 2 hours of post-operative routine chest X-ray. A severity score was given to each examination in each technique. Lung ultrasound and chest X-ray results were compared by three methods: absolute comparison of normal to abnormal, the degree of pathology, and the clinical findings’ relevance.

Results

Eighty patients were enrolled from 2013 to 2017, and 215 ultrasonography images were obtained. For pneumothorax, the precise overlap was found in 129/180 (72%) images. In 24% of examinations, X-ray missed ultrasonography findings. There was an agreement between studies in 80/212 (38%) images for pleural effusion. 60% of pleural effusions were missed by chest X-ray and detected by ultrasonography, and only 2.4% were missed by ultrasound, all very small. Clinically relevant fluid accumulation found a precise match in 80%, and 20% were found only by lung ultrasound. For lung consolidation, a 100% overlap was found with both methods.

Conclusions

Our results suggest that lung ultrasound may replace chest X-ray as the standard examination in the postoperative care of patients undergoing thoracic surgical procedures.

Can Chest Ultrasound Replace Chest X-ray in Thoracic Surgery?

Background: There is growing evidence that supports the use of chest ultrasound (CUS) versus conventional chest X-ray (CXR) in order to diagnose postoperative complications. However, data regarding its use after thoracic surgery are scarce and contradictory. The aim of this study was to conduct a systematic review to evaluate the accuracy of CUS after thoracic surgery. Methods: An electronic search in MEDLINE (via PubMed), complemented by manual searches in article references, was conducted to identify eligible studies. Results: Six studies with a total of 789 patients were included in this meta-analysis. Performing CXR decreased in up to 61.6% of cases, with the main reasons for performing CXR being massive subcutaneous emphysema or complex hydrothorax. Agreement between CUS and routine-based therapeutic options was, in some studies, up to 97%. Conclusions: The selectively postoperative use of CUS may reduce the number of routinely performed CXR. However, if CUS findings are inconclusive, further radiological examinations are obligatory.

Sensitivity of chest ultrasound for postoperative pneumothorax in comparison to chest X-ray after lung resecting surgery

OBJECTIVES

Thoracic ultrasound is superior to chest X-ray for the detection of a pneumothorax in trauma and intensive care medicine. Data regarding its use in non-cardiac thoracic surgery are scarce and contradictory. Previous studies are heterogeneous regarding sonographic methodology and patient selection. This study aimed to evaluate the accuracy of thoracic ultrasound for pneumothorax assessment after lung resecting surgery in unselected patients.

METHODS

SONOR (SONOgraphy vs x-Ray) is a prospective observational trial (registry-ID DRKS00014557). A total of 123 consecutive patients with lung resecting surgery received a standardized thoracic ultrasound the same day and in addition to routine chest X-rays in erect position after removal of the chest tube. The sonographer was blinded to radiological findings and vice versa.

RESULTS

Sensitivity, specificity, positive and negative predictive values of ultrasound after removing the chest tube were 0.32, 0.85, 0.54, 0.69 for any pneumothorax and 1.0, 0.82, 0.19, 1.0 for pneumothorax ≥3 cm. No clinically relevant pneumothorax was missed. The agreement between sonography- and routine-based therapeutic decisions was 97%. Lung pulse was the most frequently detected sign to sonographically rule out a pneumothorax.

CONCLUSIONS

Postoperative thoracic ultrasound in unselected patients has a low overall sensitivity to detect a residual pneumothorax; however, its sensitivity and negative predictive values regarding clinically relevant pneumothorax are high. Test quality depends on the distinct sonographic methodology and patient selection. Anatomic differences in postsurgical and medical patients may be responsible for the contradictory results of previous trials. Studies with a larger population size are required to validate the accuracy of relevant pneumothoraces and identify appropriate selection criteria.

CLINICAL TRIAL REGISTRATION NUMBER

DRKS-German Clinical Trials Register, www.drks.de, registry-ID DRKS00014557.

Most patient conditions do not a priori debilitate the sensitivity of thoracic ultrasound in thoracic surgery-a prospective comparative study

Background

The few existing studies on the accuracy of lung ultrasound in the detection of a postoperative pneumothorax after thoracic surgery differ in the sonographic technique and the inclusion criteria. Several conditions are considered unfavourable in the sonographic examination of the lung. We aim to test these conditions for their impact on the diagnostic accuracy of lung ultrasound.

Methods

We compared lung ultrasound and chest roentgenograms for the detection of a pneumothorax after lung-resecting surgery in two prospective trials (register ID DRKS00014557 and DRKS00020216). The ultrasound examiners and radiologists were blinded towards the corresponding findings. We performed posthoc subgroup analyses to determine the influence of various patient or surgery related conditions on the sensitivity and specificity of ultrasound in the detection of pneumothorax.

Results

We performed 340 examinations in 208 patients. The covariates were age, gender, body mass index, smoking status, severity of chronic obstructive pulmonary disease, previous ipsilateral operation or irradiation, thoracotomy, postoperative skin emphysema, indwelling chest tube and X-ray in supine position. In univariate analysis, an indwelling chest-tube was associated with a higher sensitivity (58%, p = 0.04), and a postoperative subcutaneous emphysema with a lower specificity (73% vs. 88%, p = 0.02). None of the other subgroups differed in sensitivity or specificity from the total population .

Conclusions

Most of the patient- or surgery related conditions usually considered unfavourable for lung ultrasound did not impair the sensitivity or specificity of lung ultrasound. Further studies should not excluce patients with these conditions, but test the accuracy under routine conditions.

Trial registration

DRKS, DRKS00014557, registered 06/09/2018, https://www.drks.de/drks_web/navigate.do?navigationId=trial.HTML&TRIAL_ID=DRKS00014557 and DRKS00020216, registered 03/12/2019, https://www.drks.de/drks_web/navigate.do?navigationId=trial.HTML&TRIAL_ID=DRKS00020216

Supplementary Information

The online version contains supplementary material available at 10.1186/s13019-021-01454-6.

Assessment of lung ultrasound for early detection of respiratory complications in thoracic surgery

BACKGROUND AND OBJECTIVES

To assess lung ultrasound for the diagnosis and monitoring of respiratory complications in thoracic surgery.

METHODS

Prospective observational study in a University hospital, single institution. Adult patients scheduled for pulmonary resection surgery excluding pneumonectomy. An ultrasound follow-up was performed from the day before the surgery to the third day after surgery with calculation of B-line and lung score (reaeration and loss of aeration scores). Respiratory complications were collected throughout the hospitalization period.

RESULTS

Fifty-six patients were included. Eighteen patients presented a respiratory complication (32%), and they presented significantly higher BMI and ASA scores. Patients operated by videothoracoscopy were less at risk of complications. At day 3, a reaeration score ≤ 2 on the ventilated side or ≤ -2 on the operated side, and a B-line score>6 on the operated side were in favor of a complication.

CONCLUSION

Lung ultrasound can help in the diagnosis of respiratory complications following pulmonary resection surgery.

Chest Ultrasound Can Reduce the Use of Roentgenograms in Postoperative Care After Thoracic Surgery

BACKGROUND

Roentgenography remains the standard imaging modality after thoracic surgery. Trials from intensive medicine proved a high accuracy of ultrasound examination in the diagnosis of various conditions. The assumption was that ultrasound examination could reduce the number of roentgenograms after thoracic surgery.

METHODS

This prospective study compared ultrasound examinations performed by thoracic surgeons with roentgenograms in the diagnosis of pneumothorax and pleural effusion after noncardiac thoracic surgery. Patients received 2 ultrasound scans, the first on the day of surgery and the second before chest tube removal.

RESULTS

A total of 297 patients underwent 545 examinations; 336 ultrasound scans (61.6%) showed neither pneumothorax nor pleural effusion. Pneumothorax was detected on 69 roentgenograms and 51 ultrasound scans. Both modalities showed positive results in 32 cases and negative results in 395 cases (Cohen's κ, 53.4%). Ultrasound missed 37 clinically irrelevant pneumothoraces. Roentgenograms missed 19 pneumothoraces; 15 of them were clinically irrelevant. Sensitivity and specificity were 59.4% and 95.9% in the first examination and 50.0% and 94.8% in the second examination, respectively. Pleural effusion was detected on 169 roentgenograms and 117 ultrasound scans. Both modalities showed positive results in 88 cases and negative results in 336 cases (Cohen's κ, 49.6%). Ultrasound scans missed 81 pleural effusions; except for 5 cases, the clinical decisions would not have changed. Roentgenograms missed 29 clinically irrelevant pleural effusions. Sensitivity and specificity were 44.4% and 92.6% in the first examination and 60.9% and 91.3% in the second examination, respectively.

CONCLUSIONS

Given high specificities, a large share of results without pneumothorax and pleural effusion, and mismatch analysis, we could reduce the number of roentgenograms by 61.6% by using ultrasound as a primary imaging modality.

Sensitivity of lung ultrasound for the detection of pneumothorax one day after pulmonary resection—a prospective observational study

Background

Chest X‑ray (CXR) after thoracic surgery contributes to patient discomfort and costs and is of limited therapeutic value. Lung ultrasound (LU) for pneumothorax may be an alternative to CXR, but diagnostic accuracy data are heterogeneous and biased by insufficient sonographic technique and patient selection. Reported sensitivities range from 0.21 to 1.0. We evaluated the sensitivity of LU on the first day after thoracic surgery under routine conditions.

Methods

We performed a prospective observational study (trial-ID DRKS00014557). Consecutive patients undergoing lung resection received standardized LU in addition to routine CXR on the first postoperative day. Ultrasound examiner and radiologist were blinded to corresponding X‑ray and ultrasound findings. CXR was used as reference to determine diagnostic test performance of ultrasound. The conformity of sonography- and routine-based therapeutic decisions was evaluated.

Results

A total of 68 patients were examined. The mean duration of ultrasound was 145 ± 64 s. CXR identified 23 patients with pneumothorax with a mean apex-to-cupola size of 1.5 ± 1.0 cm. Ultrasound detected 18 patients with pneumothorax. The computed sensitivity of LU was 0.48 (95% confidence interval [0.36; 0.60]). Specificity was between 0.81 and 1.0, the negative predictive value 0.76 [0.66; 0.86]. The sensitivity of CXR was 0.56 [0.44; 0.68]. Air leakage via chest tube correlated weakly with CXR (spearman’s rho = 0.26) and moderately with LU (rho = 0.43). The conformity between sonographically based recommendations and the actual therapy based on routine diagnostics was 96%.

Conclusions

Sensitivity of ultrasound for pneumothorax detection nearly reached CXR and resulted in equally safe patient management. Our data can serve as a pilot study for upcoming larger-scaled controlled trials.

Routine lung ultrasound to detect postoperative pulmonary complications following major abdominal surgery: a prospective observational feasibility study

Background

Postoperative pulmonary complications after major abdominal surgery are associated with adverse outcome. The diagnostic accuracy of chest X-rays (CXR) to detect pulmonary disorders is limited. Alternatively, lung ultrasound (LUS) is an established evidence-based point-of-care diagnostic modality which outperforms CXR in critical care. However, its feasibility and diagnostic ability for postoperative pulmonary complications following abdominal surgery are unknown. In this prospective observational feasibility study, we included consecutive patients undergoing major abdominal surgery with an intermediate or high risk developing postoperative pulmonary complications according to the Assess Respiratory risk In Surgical patients in CATalonia (ARISCAT) score. LUS was routinely performed on postoperative days 0–3 by a researcher blinded for CXR or other clinical findings. Then, reports were drawn up for LUS concerning feasibility and detection rates of postoperative pulmonary complications. CXRs were performed on demand according to daily clinical practice. Subsequently, we compared LUS and CXR findings.

Results

A total of 98 consecutive patients with an ARISCAT score of 41 (34–49) were included in the study. LUS was feasible in all patients. In 94 (95%) patients, LUS detected one or more postoperative pulmonary complications during the first four postoperative days. On day 0, LUS detected 31 out of 43 patients (72.1%) with one or more postoperative pulmonary complications, compared to 13 out of 36 patients (36.1%) with 1 or more postoperative pulmonary complications detected with CXR RR 2.0 (95 CI [1.24–3.20]) (p = 0.004). The number of discordant observations between both modalities was high for atelectasis 23 (43%) and pleural effusion 29 (54%), but not for pneumothorax, respiratory infection and pulmonary edema 8 (15%), 3 (5%), and 5 (9%), respectively.

Conclusions

This study shows that LUS is highly feasible and frequently detects postoperative pulmonary complications after major abdominal surgery. Discordant observations in atelectasis and pleural effusions for LUS and CXR can be explained by a superior diagnostic ability of LUS in detecting these conditions. The effects of LUS as primary imaging modality on patient outcome should be evaluated in future studies.

Postoperative chest ultrasound findings and effectiveness after thoracic surgery: A pilot study

The aim of this study was to analyze the information from post-operative chest ultrasound (CU) to evaluate the possibility to use this method instead of chest X-ray (CXR) after thoracic surgery. Patients who underwent thoracic surgery were evaluated with CU blinded to CXR after surgery, deciding if it was useful or CU was exhaustive. Twenty-four patients were enrolled prospectively. The CU allowed a further discrimination of the lung abnormalities, discriminating between atelectasis, infections or hematoma. CXR was required in only 5 cases due to the presence of massive subcutaneous emphysema or absence of lung point. In the remaining 19 cases, CU was considered exhaustive and effective. In particular, CU was considered exhaustive in 67% of cases after open surgery and in 85% of cases after video-assisted thoracic surgery. In conclusion, CU appears to be effective in post-operative management after thoracic surgery and it can increase the diagnostic accuracy reducing any unnecessary X-ray exposure.

Preoperative assessment of chest wall invasion in non-small cell lung cancer using surgeon-performed ultrasound

BACKGROUND

Chest wall invasion in operable lung cancer upgrades the stage and can affect operative planning. Diagnosing chest wall invasion preoperatively is important in patient consent, in the choice of operative incision placement, and can be helpful in choosing an operative approach (open vs thoracoscopic). The objectives of this study were to determine the diagnostic accuracy of preoperative, surgeon-performed ultrasound (US) in assessing tumoral chest wall invasion (T3) in non-small cell lung cancer (NSCLC) patients and to compare its accuracy vs preoperative computed tomography (CT).

METHODS

This study was a prospective clinical trial (ClinicalTrials.gov: NCT01206894) that prospectively enrolled patients between September 2010 and January 2013. Eligible patients included those with NSCLC abutting the parietal pleura or invading the chest wall on preoperative CT scan of the chest and who were planned for surgical resection. Criteria for chest wall invasion on US included (1) disruption of the parietal pleura, (2) invasion of the ribs, or (3) impairment of pleural movement with respiration. The US chest wall examination was performed by the thoracic surgical team immediately before the surgical intervention. Sensitivity and specificity for CT scan and US in assessing chest wall invasion were calculated using definitive chest wall invasion on final pathologic analysis as the gold standard for chest wall invasion.

RESULTS

During a 28-month period, 28 patients (15 men and 13 women) patients were prospectively enrolled. Mean age was 62 ± 11 years, and mean body mass index was 25.3 ± 4.5 kg/m(2). The average time for surgeon-performed US assessment looking for chest wall invasion was 5.3 ± 5 minutes. The sensitivity of US in evaluating chest wall invasion was 90.9% and the specificity was 85.7%. CT scan was associated with a sensitivity of 61.5% and a specificity of 84.6%. The positive and negative predictive values of surgeon-performed US for tumoral chest wall invasion were 83.3% and 92.3%, respectively, compared with 80% and 68.8% for CT scan.

CONCLUSIONS

Surgeon-performed preoperative chest wall US can reliably diagnose tumoral chest wall invasion in patients with NSCLC. CT scan has poor sensitivity in predicting chest wall invasion preoperatively. Surgeon-performed US can be considered as a complementary adjunct to preoperative imaging in patients with pulmonary lesions abutting the chest wall to improve preoperative diagnosis, staging, and operative planning.

The feasibility of nurse practitioner-performed, telementored lung telesonography with remote physician guidance - 'a remote virtual mentor'

Background

Point-of-care ultrasound (POC-US) use is increasingly common as equipment costs decrease and availability increases. Despite the utility of POC-US in trained hands, there are many situations wherein patients could benefit from the added safety of POC-US guidance, yet trained users are unavailable. We therefore hypothesized that currently available and economic ‘off-the-shelf’ technologies could facilitate remote mentoring of a nurse practitioner (NP) to assess for recurrent pneumothoraces (PTXs) after chest tube removal.

Methods

The simple remote telementored ultrasound system consisted of a handheld ultrasound machine, head-mounted video camera, microphone, and software on a laptop computer. The video output of the handheld ultrasound machine and a macroscopic view of the NP's hands were displayed to a remote trauma surgeon mentor. The mentor instructed the NP on probe position and US machine settings and provided real-time guidance and image interpretation via encrypted video conferencing software using an Internet service provider. Thirteen pleural exams after chest tube removal were conducted.

Results

Thirteen patients (26 lung fields) were examined. The remote exam was possible in all cases with good connectivity including one trans-Atlantic interpretation. Compared to the subsequent upright chest radiograph, there were 4 true-positive remotely diagnosed PTXs, 2 false-negative diagnoses, and 20 true-negative diagnoses for 66% sensitivity, 100% specificity, and 92% accuracy for remotely guided chest examination.

Conclusions

Remotely guiding a NP to perform thoracic ultrasound examinations after tube thoracostomy removal can be simply and effectively performed over encrypted commercial software using low-cost hardware. As informatics constantly improves, mentored remote examinations may further empower clinical care providers in austere settings.