Diagnostic Accuracy of Using Point-of-care Ultrasonography for Confirming Nasogastric Tube Placement

Active, not recruiting

• Conditions: Nasogastric Tube Placement; Ultrasound; Nasogastric Tube

• Registration Number: NCT06821737
• Lead Sponsor: Pamela Youde Nethersole Eastern Hospital

Brief Summary

A prospective observational diagnostic study will be conducted to assess the sensitivity and specificity of ultrasound in verifying the correct nasogastric tube placement, using X-ray as the reference standard.

Detailed Description

This study is a prospective observational diagnostic investigation aimed at evaluating the accuracy of ultrasound in confirming nasogastric tube (NGT) placement. Participants aged 18 years or older requiring NGT insertion will be recruited via convenience sampling from community nursing centres across five clusters and medical and geriatric wards in four acute or convalescent hospitals. Nurses performing index tests will complete standardized POCUS training (8-hour theory and practical sessions, written exams, 3-month bedside practicum with ≥20 positive scans) prior to competency assessment. Direct visualisation of an NGT in both the oesophagus and stomach will be interpreted as correct stomach placement. When the acoustic shadow of an NGT was not seen in the stomach, 50cc of air was injected through the NGT, and it was considered well-placed if the ultrasonography showed dynamic fogging. Correct gastric placement is assumed if the acoustic shadow of an NGT is visible in the oesophagus and stomach, even if fogging is not detectable. The reference standard will be post-index test X-ray confirmation. Diagnostic performance metrics, including sensitivity, specificity, positive and negative predictive values, and likelihood ratios, will be calculated to assess the efficacy of ultrasound. Variability in diagnostic accuracy across participant characteristics will be analyzed. Additionally, the study will compare the time intervals between ultrasound and X-ray, delays in feeding initiation post-placement, and associated costs, including emergency department admissions, unplanned hospitalizations, and ambulance transportation.

The findings will provide critical evidence on the diagnostic utility of ultrasound for NGT placement verification, informing potential revisions to clinical practice guidelines and supporting stakeholder decisions on integrating ultrasound as a reference test.

Study Timeline

• Study First Submitted: 2025-02-06
• Study First Submitted QC: 2025-02-06
• Study First Posted: 2025-02-12
• Study Start: 2025-04-28
• Status Verified: 2025-07
• Last Update Submitted: 2025-07-04
• Last Update Posted: 2025-07-09
• Primary Completion: 2026-10
• Study Completion: 2028-10-01

Recruitment & Eligibility

• Status: ACTIVE_NOT_RECRUITING
• Sex: All
• Target Recruitment: 530

Inclusion Criteria

• Aged 18 or older;
• Living in the community or admitted to a medical and geriatric ward;
• Requiring the use of an NGT during the recruitment period for assessment, monitoring, nutritional assistance, drainage, and/or medication administration;
• Aspirated fluids with a pH value of more than 5.5 after insertion or with insufficient fluids for pH testing after insertion;

Exclusion Criteria

• Uncooperative patients;
• Had head and neck injury
• Have had a gastrectomy or by-pass surgery;
• History of abdominal trauma or receiving emergency life support intervention at time of recruitment.

Study & Design

• Study Type: OBSERVATIONAL
• Study Design: Not specified

Primary Outcome Measures

Name	Time	Method
Diagnostic Accuracy of Ultrasound in correct Nasogastric Tube placement confirmation	An average of 18 months	Sensitivity: True Positive / (True Positive + False Negative) x 100% Specificity: True Negative / (True Negative + False Positive) x 100% Positive Predictive Value: True Positive / (True Positive + False Positive) x 100% Negative Predictive Value: True Negative / (True Negative + False Negative) x 100% Positive Likelihood Ratio: sensitivity / 1 - specificity Negative Likelihood Ratio: 1 - sensitivity / specificity

Secondary Outcome Measures

Name	Time	Method
Time lag between USG & x-ray	An average of 18 months	The study will assess the time lag between ultrasound confirmation and subsequent X-ray imaging for nasogastric tube placement verification.
Delay between tube placement and feeding by x-ray	An average of 18 months	The study will evaluate the delay between nasogastric tube placement and the initiation of feeding, as confirmed by X-ray.
Cost of ED admission, unplanned admission, ambulance transportation	An average of 18 months	The study will analyze costs associated with Emergency Department admissions, unplanned hospital admissions, and ambulance transportation related to nasogastric tube placement confirmation.

Trial Locations

Locations (1)

Hospital Authority, HKSAR; 🇭🇰 Hong Kong, Hong Kong