Is α-Amylase an Important Biomarker to Detect Aspiration of Oral Secretions in Ventilated Patients?

Predicting ventilator-associated pneumonia in elderly patients requiring mechanical ventilation through the detection in tracheal aspirates

OBJECTIVE

In this study, we evaluated the clinical utility of tracheal aspirates α-amylase (AM), pepsin, and lipid-laden macrophage index (LLMI) in the early diagnosis of ventilator-associated pneumonia (VAP) in elderly patients on mechanical ventilation.

METHODS

Within 96 hours of tracheal intubation, tracheal aspirate specimens were collected from elderly patients on mechanical ventilation; AM, pepsin, and LLMI were detected, and we analyzed the potential of each index individually and in combination in diagnosing VAP.

RESULTS

Patients with VAP had significantly higher levels of AM, pepsin, and LLMI compared to those without VAP (P < 0.001), and there was a positive correlation between the number of pre-intubation risk factors of aspiration and the detection value of each index in patients with VAP (P < 0.001). The area under a receiver operating characteristic (ROC) curve (AUC) of AM, pepsin, and LLMI in diagnosis of VAP were 0.821 (95% CI:0.713-0.904), 0.802 (95% CI:0.693-0.892), and 0.621 (95% CI:0.583-0.824), the sensitivities were 0.8815, 0.7632, and 0.6973, the specificities were 0.8495, 0.8602, and 0.6291, and the cutoff values were 4,321.5 U/L, 126.61 ng/ml, and 173.5, respectively. The AUC for the combination of indexes in diagnosing VAP was 0.905 (95% CI:0.812-0.934), and the sensitivity and specificity were 0.9211 and 0.9332, respectively. In the tracheal aspirate specimens, the detection rate of AM ≥ cutoff was the highest, while it was the lowest for LLMI (P < 0.001). The detection rates of AM ≥ cutoff and pepsin ≥ cutoff were higher within 48 hours after intubation than within 48-96 hours after intubation (P < 0.001). In contrast, the detection rate of LLMI ≥ cutoff was higher within 48-96 hours after intubation than within 48 hours after intubation (P < 0.001). The risk factors for VAP identified using logistic multivariate analysis included pre-intubation aspiration risk factors (≥3), MDR bacteria growth in tracheal aspirates, and tracheal aspirate AM ≥ 4,321.5 U/L, pepsin ≥ 126.61 ng/ml, and LLMI ≥ 173.5.

CONCLUSION

The detection of AM, pepsin, and LLMI in tracheal aspirates has promising clinical utility as an early warning biomarker of VAP in elderly patients undergoing mechanical ventilation.

Thoracic ultrasound alone or in combination with tracheal amylase as a tool predictor of ventilator-associated pneumonia in neurocritical patients

In this study, we aim to evaluate whether thoracic ultrasound (TUS) and tracheal amylase (TA) alone or in combination can predict the development of ventilator-associated pneumonia (VAP) in neurocritical patients. Consecutive adult patients with neurocritical disease with normal chest radiographs who required intensive care unit admission and mechanical ventilation between March 2015 and July 2018 were included. TUS and Amylase levels were measured during the first 24 hours and repeated 48 hours after orotracheal intubation. Forty-three patients with a median age of 34 years (17-82) were included. TUS had a sensitivity of 100% and specificity of 96.3% as a predictor of VAP within the first 48 hours when nonpattern A was observed. TA levels > 200 UI/L in the first 48 hours had a sensitivity of 87.5%, and specificity of 63% as a predictor of VAP. Moreover, no benefit of TUS plus TA compared to TUS alone as a predictor of VAP was found. The identification of abnormal TUS patterns in the first 48 hours of orotracheal intubation is a significant predictor of VAP in neurocritical patients.

Neuromuscular electrical stimulation improves swallowing initiation in patients with post-stroke dysphagia

Objective

More than half of post-stroke patients develop dysphagia, which manifests as delayed swallowing and is associated with a high risk of aspiration. In this study, we aimed to investigate the immediate effect of neuromuscular electrical stimulation (NMES) on swallowing initiation in post-stroke patients using videofluoroscopic swallowing study (VFSS) data.

Materials and methods

This randomized, self-controlled crossover study included 35 patients with post-stroke dysphagia. All selected patients received real and sham NMES while swallowing 5 ml of thin liquid. Participants completed the conditions in random order, with a 10-min interval between conditions. The primary evaluation indicators included the Modified Barium Swallow Impairment Profile-6 (MBSImp-6) and Penetration-Aspiration Scale (PAS). Secondary indicators included oral transit time (OTT), pharyngeal transit time (PTT), and laryngeal closure duration (LCD).

Results

Modified Barium Swallow Impairment Profile-6 (P = 0.008) and PAS (P &lt; 0.001) scores were significantly lower in the Real-NMES condition than in the Sham-NMES condition. OTT (P &lt; 0.001) was also significantly shorter during Real-NMES than during Sham-NMES. However, LCD (P = 0.225) and PTT (P = 0.161) did not significantly differ between the two conditions.

Conclusion

Neuromuscular electrical stimulation may represent a supplementary approach for promoting early feeding training in patients with post-stroke dysphagia.

Clinical trial registration

[https://clinicaltrials.gov/], identifier [ChiCTR2100052464].

Pepsin A in Tracheal Secretions From Patients Receiving Mechanical Ventilation

BACKGROUND

In patients in the intensive care unit (ICU) receiving mechanical ventilation, aspiration of gastric contents may lead to ventilator-associated events and other adverse outcomes. Pepsin in pulmonary secretions is a biomarker of microaspiration of gastric contents.

OBJECTIVES

To evaluate the association between tracheal pepsin A and clinical outcomes related to ventilator use.

METHODS

A subset of 297 patients from a larger clinical trial on aspiration of oral secretions in adults receiving mechanical ventilation consented to have pepsin A measured in their tracheal aspirate samples. A concentration ≥6.25 ng/mL indicated a positive result. Abundant microaspiration was defined as pepsin A in ≥30% of samples. Statistical analyses included analysis of variance, analysis of covariance, and χ2 tests.

RESULTS

Most patients were White men, mean age 59.7 (SD, 18.8) years. Microaspiration was found in 43.8% of patients (n = 130), with abundant microaspiration detected in 17.5% (n = 52). After acuity was controlled for, patients with tracheal pepsin A had a longer mechanical ventilation duration (155 vs 104 hours, P < .001) and ICU stay (9.9 vs 8.2 days, P = .04), but not a longer hospital stay.

CONCLUSIONS

Microaspiration of gastric contents occurred in nearly half of patients and was associated with a longer duration of mechanical ventilation and a longer stay in the ICU. Additional preventative interventions beyond backrest elevation, oropharyngeal suctioning, and management of endotracheal tube cuff pressure may be needed. Also, the timing of pepsin measurements to capture all microaspiration events requires additional exploration.