Usefulness of Clinical Prediction Rules, D-dimer, and Arterial Blood Gas Analysis to Predict Pulmonary Embolism in Cancer Patients

PrEdictive value of coMbined pre-test proBability and blOod gas anaLysis In pulmonary emboliSM-the EMBOLISM study

In patients with suspected pulmonary embolism (PE), the number of unnecessary computed tomography pulmonary angiography (CTPA) scans remains high, especially in patients with low pre-test probability (PTP). So far, no study showed any additional benefit of capillary blood gas analysis (BGA) in diagnostic algorithms for PE. In this retrospective analysis of patients with suspected PE and subsequent CTPA, clinical data, D-dimer levels and BGA parameters (including standardized PaO2) were analyzed. Logistic regression analyses were performed to identify independent predictors for PE and reduce unnecessary CTPA examinations in patients with low PTP according to Wells score. Of 1538 patients, PE was diagnosed in 433 patients (28.2%). The original Wells score (odds ratio: 1.381 [95% CI 1.300-1.467], p < 0.001) and standardized PaO2 (odds ratio: 0.987 [95% CI 0.978-0.996], p = 0.005) were independent predictors for PE. After cohort adjustment for low PTP a D-dimer cut-off < 1.5 mg/L (278 patients (18.1%) with 18 PE (6.5%)) was identified in which a standardized PaO2 > 65 mmHg reduced the number of unnecessary CTPA by 31.9% with a 100% sensitivity. This approach was further validated in additional 53 patients with low PTP. In this validation group CTPA examinations were reduced by 32.7%. No patient with PE was missed. With our novel algorithm combining BGA testing with low PTP according to Wells score, we were able to increase the D-Dimer threshold to 1.5 mg/L and reduce CTPA examinations by approximately 32%.

D-dimer value in the diagnosis of pulmonary embolism-may it exclude only?

Background

Pulmonary embolism (PE) is the third most common cause of death for cardiovascular diseases in Europe. Quick PE diagnosis is therefore crucial for prognosis improvement. It is critical to have suitable screening tests both to exclude PE as well to select patient with highest likelihood of PE occurrence. Currently D-dimer test is accepted as important tool useful to exclude PE in low risk patients. Our goal was to assess the D-dimer test positive prognostic value.

Methods

A retrospective study based on medical record analysis of consecutively admitted patients to 9 wards of The University Clinical Center in Katowice who were hospitalized during four consecutive years was performed. Three hundred and seventy patients met the inclusion criteria for the study, which involved the D-dimer tests and computed tomographic pulmonary angiography (CTPA) performed during hospitalization. Assessed patients were divided into two groups: PE confirmed and PE excluded by CTPA.

Results

We have found that patients with D-dimer levels higher than 2,152 ng/mL had significantly increased risk of PE [area under curve (AUC) of 0.69; 95% CI, 0.64-0.75; P<0.05]. Positive predictive value (PPV) reached the level of 53%, whereas negative predictive value (NPV) reached 82%. We also found that patients with the history of neoplasm and at >65 years of age had D-dimer cut-off point moved to the level of 2,652 ng/mL (AUC of 0.67; 95% CI, 0.52-0.81; P<0.05).

Conclusions

Whereas the NPV of the D-dimer test is generally accepted our results suggest that, in selected cases, an increased plasmatic D-dimer levels may have PPV in PE diagnosis. Patients with the history of neoplasm have higher cut-off D-dimer points above which we should consider increased PE likelihood. CTPA should be considered even for patients with low probability of PE when D-dimer values exceed four times the normal level.

[Effect of High-frequency Chest Wall Oscillatory on Lung Function in Patient After Single Port Video-assisted Thoracoscopic Surgery Lobectomy]

BACKGROUND

It has been confirmed that high-frequency chest wall oscillatory (HFCWO) is a new type of auxiliary sputum discharge device. However, up to now, the specific therapeutic effect of HFCWO is still uncertain. This study aimed to compare the changes of the sputum volume before and after the treatment of HFCWO, and to investigate the effect of HFCWO on lung function and arterial blood gas analysis after single port video-assisted thoracoscopic surgery lobectomy (S-VATS).

METHODS

A total of 90 patients with S-VATS lobectomy were collected in the Second Affiliated Hospital of Soochow University from January 2017 to December 2017, which were randomly divided into the experimental group with HFCWO (n=45) and the control group (n=45) with routine clapping, respectively. The sputum volume of the two groups was measured 5 days before operation. Lung function and arterial blood gas analysis was measured before and 7th days after surgery.

RESULTS

The sputum volume was higher in the experimental group than that of the control group after surgery, there was statistically significant difference for the first three days (P<0.05). There was no statistically significant difference between the two groups in forced expiratory volume in one second (FEV₁), forced vital capacity (FVC) and oxygen partial pressure (PaO₂) before surgery (P>0.05); Compared with those before surgery, FEV₁, FVC and PaO₂ decreased in both groups after surgery (P<0.05); However, FEV₁, FVC and PaO₂ in the experimental group were higher than those in the control group (P<0.05); There was no statistically significant difference in preoperative and postoperative partial pressure of carbon dioxide (PaCO₂) between the two groups (P>0.05).

CONCLUSIONS

HFCWO can significantly increase the amount of sputum excretion, improve lung function and alleviate hypoxia status after S-VATS lobectomy. This study provides a promising approach for HFCWO toward hypoxia status after S-VATS lobectomy.
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