01Purpose and principlesWhat the assessment is for and the core concepts behind it.
Device interpretation is a structured safety task. First confirm the current image belongs to the correct patient and was acquired after the relevant insertion or adjustment. Identify all devices, determine their purpose, trace each entire course, locate tip and side holes, and inspect the organs traversed. Then search for complications and issue an unambiguous action statement. A list of centimetre targets without this reasoning can miss a device in the wrong structure.
Airway tubes move with neck flexion and extension. An endotracheal tip should lie in the trachea at a safe distance from the carina for the patient and head position; right mainstem placement can collapse the left lung. Enteric tubes require a continuous oesophageal course, passage below the diaphragm and an appropriate gastric endpoint before use. A tip below the diaphragm alone is unsafe if the tube first travelled through a bronchus.
Vascular devices follow expected anatomy. A catheter may be too proximal for reliable therapy, too deep with arrhythmia or perforation risk, or outside the venous system. Chest drains need intrapleural side holes and a patent external system. Pacemaker and defibrillator leads should have intact generators and expected chamber trajectories, but function cannot be certified from radiography alone. Clinical review and device interrogation remain necessary.
Key points
- Identify every visible device and trace it continuously from entry point to tip; checking only the tip misses knots, kinks, wrong-lumen course and side holes outside the body.
- For an NG tube film, confirm the current correct patient, adequate lower-centred image, oesophageal course, passage across the diaphragm and tip within the stomach before documenting whether use may proceed.
- If the patient deteriorates or a device course is unsafe or indeterminate, stop using it, treat the complication, escalate directly and obtain further imaging only when it does not delay urgent care.
- Judge endotracheal and tracheostomy devices relative to the carina, head position and airway anatomy and look for lobar collapse or pneumothorax.
- Judge vascular catheters by their entire expected venous course, tip location, indication and complication; acceptable positions differ between temporary CVCs, dialysis lines, PICCs and ports.
- After any adjustment, verify the current position and document the explicit action because an earlier satisfactory film does not validate a moved device.
02Indications, selection and cautionsWhen it is useful, when urgency changes and important limitations.
Trace the airway tube and relate its tip to the carina and head position; assess both lungs for collapse, aspiration and procedure-related pleural air.
The tube should descend through the oesophagus, cross the diaphragm centrally and end in the stomach; use requires documented competent review of the current image.
Follow the expected venous route to the lower superior vena cava or cavoatrial region appropriate to device purpose and examine for pneumothorax, bleeding or maldirection.
Confirm side holes lie within the thorax and tubing is not kinked; intrafissural or extrapleural location may fail to drain the intended collection.
Identify generator and lead count, continuity and chamber trajectories and compare prior images; suspected displacement or fracture needs ECG and device interrogation.
New shock, hypoxia, arrhythmia or pleural change after insertion demands immediate clinical assessment and direct communication before device use.
03Method and interpretationA systematic approach to the test and its findings.
Read from the initial assessment onwards. Tests may run in parallel in urgent care; first-line, preferred, confirmatory, definitive and gold-standard labels appear only when the chapter explicitly states them.
- 01
Current post-procedure chest radiographFirst step - Why
- Assess the complete device course, endpoint and immediate thoracic complications.
- Interpretation and limitations
- Confirm timing and projection and compare with the insertion record; a limited image that excludes the tip or both pleurae cannot answer the safety question.
- 02
Aspirate pH testing for NG placement - Why
- Provide the initial bedside method for confirming nasogastric tube placement when aspirate is obtainable.
- Interpretation and limitations
- Use only approved pH strips and the current national or local threshold; chest radiography is the second-line test when bedside confirmation is unsuccessful or inappropriate.
- 03
Targeted repeat radiograph - Why
- Confirm position after repositioning or improve an image that did not include essential anatomy.
- Interpretation and limitations
- State the exact changed device and do not rely on an older film acquired before movement, transport or retaping.
- 04
CT or fluoroscopic device assessment - Why
- Resolve an indeterminate or apparently extravascular course and define suspected perforation or deep complication.
- Interpretation and limitations
- Choose the modality for the device and urgency; unstable physiology may require immediate treatment before cross-sectional confirmation.
- 05
ECG and electronic device interrogation - Why
- Assess pacemaker or defibrillator function when lead displacement, fracture or failure is suspected.
- Interpretation and limitations
- Normal radiographic appearance does not prove capture or sensing, and abnormal function can occur without a visible break.
04Clinical next stepsHow the result changes management or prompts escalation.
01Worked case: NG confirmationTube position before first feedFirst stepAspirate pH is unavailable and a lower-centred chest radiograph has been obtained after NG insertion.+
- 1Confirm the current correct-patient film includes the entire tube from upper oesophagus through both hemidiaphragms and is technically adequate.
- 2Trace the tube down the oesophagus, through the diaphragm and to a gastric tip, making sure it does not follow either bronchial tree.
- 3EscalationIf every criterion is satisfied, a trained competent interpreter records the evaluation and explicit suitability for use; otherwise withhold feed and escalate removal or repositioning.
- 4Verify that the ward receives and follows the action, and use a new confirmation process after any significant movement or replacement.
02Central-line emergencyDeterioration after venous accessA patient becomes acutely breathless or shocked immediately after central venous catheter insertion.+
- 1Stop line use, assess airway, breathing and circulation and call senior procedural and resuscitation help.
- 2Review both pleural spaces, catheter route and tip for pneumothorax, haemothorax, arterial course, perforation and deep cardiac position.
- 3During cardiac arrest, begin adult advanced life support and treat suspected tension pneumothorax immediately as a reversible cause; after return of circulation, resolve catheter position and complications before use.
03Routine device surveyMultiple devices on an ICU filmA portable film contains an airway tube, enteric tube, vascular catheters, drains and cardiac leads.+
- 1List each device by type and trace it independently from entry to endpoint using expected anatomy and its intended function.
- 2ConfirmatoryFor each device, state satisfactory, unsafe or indeterminate and name the immediate corrective or confirmatory action.
- 3Restart the survey for lung, pleural, cardiac and upper abdominal complications so device density does not conceal new disease.
05Risks, monitoring and follow-upComplications, safety checks and further assessment.
- Reassess all devices after patient transfer, significant position change, accidental traction, replacement or new unexplained deterioration.
- For NG tubes, follow the current bedside rechecking policy before use and after events that may cause displacement; do not use auscultation of insufflated air as confirmation.
- Inspect vascular and pleural insertion sites, tubing, connections and documented external length alongside the image.
- Trend ventilation, airway pressures and bilateral breath sounds after airway-device adjustment and confirm position when clinically indicated.
- Record the person, time and recipient of any urgent device-position communication and verify that the required action occurred.
06Special situationsVariants, exceptions and circumstances that change the usual approach.
Course matters more than endpoint
A tube can project below the diaphragm after traversing a bronchus and perforating lung, so the entire path must be anatomically plausible.
The film has a timestamp
A satisfactory image validates only the device position at acquisition; movement, retaping and transfer can make it obsolete.
Side holes determine drainage
A chest-drain tip may appear intrathoracic while a proximal side hole lies outside, allowing air entry and ineffective drainage.
Function needs another test
Radiography shows lead continuity and gross position, whereas ECG and interrogation establish sensing, capture and battery or circuit performance.
Words should trigger action
Reports such as tube present are inadequate when the clinical question is whether administration can begin or a device requires correction.
07Common pitfallsFrequent interpretation and management errors.
- 01
Checking only the tip of an NG tube and missing a bronchial course.
- 02
Using a central line before an unexpected course or post-procedure pleural abnormality has been resolved.
- 03
Quoting a universal endotracheal tube distance without considering head position, carina visibility and patient anatomy.
- 04
Assuming a chest drain works because its tip lies inside the thorax while its side holes or tubing are malpositioned.
- 05
Failing to communicate a dangerous device finding directly and verify the corrective action.