Glasgow Coma Scale Calculator
Structured neurological assessment for clinicians operating beyond the reach of CT scanners and neurosurgical teams.
Do not enter names, cabin numbers, booking numbers, dates of birth, or other patient-identifiable information. Use anonymized clinical details only. This tool is for education, structure and operational readiness only.
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--Verbal Response (V)
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--Total GCS Score
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Awaiting inputSelect all three GCS components above to receive maritime-specific interpretation and recommended actions for your clinical scenario at sea.
Why GCS Matters at Sea
The Glasgow Coma Scale is the global standard for assessing consciousness level, but its significance takes on a different dimension in maritime medicine. On land, a declining GCS triggers a cascade of resources: CT imaging within minutes, neurosurgical consultation, intracranial pressure monitoring, and definitive airway management by an anaesthetic team. At sea, the ship doctor has none of these. The GCS becomes not just an assessment tool but the primary decision-making framework for some of the most consequential calls in maritime clinical practice.
When a crew member falls from a ladder in the engine room and sustains a head injury, the GCS is often the only objective measure the ship doctor can use to determine whether this patient can be monitored aboard or requires immediate evacuation. There is no CT scanner to rule out an extradural haematoma. There is no neurosurgeon to call for a second opinion at 0300. The GCS, tracked serially over time, becomes the clinician's primary window into what is happening inside the cranium.
A falling GCS at sea is an emergency of the highest order. It may indicate expanding intracranial pathology that, without intervention, will kill the patient. The maritime clinician must recognise this trajectory early and initiate evacuation before the patient deteriorates beyond the point where transfer is safe or even possible. A patient with a GCS of 8 or below requires definitive airway management, and most ship medical facilities are not equipped or staffed for prolonged ventilation.
Maritime Clinical Application
Serial GCS assessment is the cornerstone of head injury management at sea. A single GCS score is a snapshot; a trend tells the story. The ship doctor should record GCS at presentation and then at regular intervals: every 15 minutes for the first two hours, every 30 minutes for the next four hours, and hourly thereafter if the patient remains stable. Any drop of two or more points, or any fall below 13, should trigger immediate escalation.
When to Escalate Based on GCS
GCS 13-15 (Minor): Monitor aboard with serial assessments. Establish telemedical contact if GCS was ever below 15 post-injury. Document mechanism of injury, anticoagulant status, and any loss of consciousness. Most patients in this range can be safely managed aboard with close observation.
GCS 9-12 (Moderate): Initiate telemedical consultation immediately. Begin active evacuation planning. Notify the bridge. Prepare for potential deterioration including airway compromise. Document GCS trend every 15 minutes. Consider the patient's position relative to the nearest port with CT capability.
GCS 3-8 (Severe): This is a time-critical emergency. The patient requires definitive airway management and neurosurgical intervention that cannot be provided aboard. Request immediate medevac. If intubation capability exists and is within the clinician's competence, secure the airway. Notify the Master for potential diversion. Every minute counts.
The MCA Ship Captain's Medical Guide and WHO International Medical Guide for Ships both emphasise the importance of GCS in maritime head injury assessment. The MCA guidance specifically recommends that any patient with a GCS below 13 following head trauma should be considered for evacuation, and any patient with a GCS of 8 or below should be treated as requiring emergency transfer to a facility with neurosurgical capability.
Medevac decision-making based on GCS must account for maritime-specific factors. A patient with a GCS of 10 who is 4 hours from a helicopter and 18 hours from port presents a different challenge than the same patient 30 minutes from a helipad. The clinician must communicate not just the GCS score but its trajectory, the time since injury, the patient's anticoagulant status, and any focal neurological signs. These details allow the telemedical adviser and coastguard to triage evacuation resources appropriately.
| GCS Range | Severity | Maritime Action |
|---|---|---|
| 13 - 15 | Minor | Monitor aboard, serial GCS, telemedical contact if post-traumatic |
| 9 - 12 | Moderate | Telemedical consult, active evacuation planning, bridge notification |
| 3 - 8 | Severe | Immediate medevac request, airway management, Master notification |
References: MCA Ship Captain's Medical Guide (2019 edition), Chapter 5; WHO International Medical Guide for Ships, 3rd edition (2007), Chapter 10; Teasdale G, Jennett B. Assessment of coma and impaired consciousness: a practical scale. Lancet. 1974;2(7872):81-84.
Last updated: May 2026
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