• 3% saline is hypertonic. It raises serum sodium and plasma osmolality.
• With an intact or partly intact blood-brain barrier, this creates an osmotic gradient that draws water from swollen brain tissue into the intravascular space.
• Result: reduced brain water and edema, lower ICP, and improved cerebral perfusion pressure (CPP). [Miller's Anesthesia, 10e, p. 6412]

• It reduces ICP without causing osmotic diuresis, so it is less likely to produce hypovolemia or hypotension.
• Maintaining blood pressure matters in SDH/ICH because hypotension can lower CPP and worsen secondary brain injury.
• The Neurocritical Care Society suggests hypertonic saline over mannitol for ICP elevation or cerebral edema in intracerebral hemorrhage, although the certainty of evidence is low. The NCS cerebral-edema guideline permits either symptom-triggered boluses or sodium-targeted therapy in ICH.

• Declining consciousness or focal neurologic deterioration
• Unequal/fixed pupils or other features of herniation
• CT evidence of significant mass effect, midline shift, compressed basal cisterns
• Documented raised ICP

• It is a temporizing treatment. A sizeable SDH with mass effect may need urgent neurosurgical evacuation, and ICH may require surgery or other definitive management.
• Monitor sodium, chloride, serum osmolality, renal function, fluid status, and acid-base balance.
• Avoid overly rapid correction if the patient has chronic hyponatremia because of osmotic demyelination risk.
• Do not use routine continuous hypertonic saline solely to maintain hypernatremia without a clear ICP/edema indication. [Miller's Anesthesia, 10e, p. 6412]

• Decreases cerebral edema and ICP
• Reduces mass effect and risk of herniation
• Improves cerebral perfusion pressure, helping maintain blood flow to the brain

What must be addressed before any transfer

1. Immediate neurosurgical decision
   • The treating hospital should urgently reassess whether the SDH needs evacuation or the intraparenchymal bleed needs an intervention before travel.
   • CT details matter: hematoma sizes, midline shift, cisternal effacement, intraventricular extension/hydrocephalus, location, and change from prior imaging.
   • Increasing bleed or declining neurological status should favor treatment locally or transfer to the nearest neurosurgical center, not a routine long-distance commercial flight.
2. Do not use an ordinary commercial flight for an unstable patient
   • No unescorted travel.
   • A patient with a progressing intracranial bleed needs critical-care air ambulance transport if transfer is unavoidable: physician/critical-care escort, continuous ECG, oxygen saturation and blood-pressure monitoring, airway and ventilator capability, suction, IV pumps, emergency medications, and ability to manage raised ICP or seizures.
   • The receiving hospital in India must have a confirmed ICU/neurosurgery bed and accept the patient before departure.
3. Stabilize and monitor before departure
   • Serial neurologic observations including GCS, pupils, limb power, speech, headache and vomiting.
   • Continuous oxygen saturation, ECG, respiratory rate, and frequent or continuous blood-pressure monitoring.
   • Avoid hypoxia, hypotension, fever, hypoglycemia, and large sodium/osmolality shifts, because all can worsen secondary brain injury.
   • Maintain head elevation around 30 degrees and neutral neck position if clinically appropriate.
   • Avoid excess hypotonic IV fluid. Hypertonic saline is used only under the treating team’s monitored protocol if there is raised ICP/edema or herniation concern, not as a substitute for surgical care.
   • Stop and urgently reverse anticoagulants when relevant, and correct significant coagulopathy or thrombocytopenia according to the treating team. Careful BP control and anticoagulant reversal reduce risk of further ICH expansion. Goldman-Cecil acute ICH treatment
4. Seizure and airway preparedness
   • Treat witnessed seizures promptly; have rescue seizure medication available in transport.
   • A patient who is drowsy, repeatedly vomiting, unable to protect their airway, has falling GCS, abnormal pupils, or unstable breathing may need airway protection before transfer, as decided by an experienced critical-care/anesthesia team.
5. Travel documentation and handover
   • Carry CT images in DICOM format and reports, including both scans and timestamps.
   • Include a concise timeline, GCS/pupil chart, medication administration times, anticoagulant/antiplatelet history, allergies, labs, blood group, coagulation tests, and contact details of the treating neurosurgeon.
   • Arrange direct handover to the named receiving neurosurgeon/ICU, not just emergency-department arrival.

Red flags that mean do not depart and require immediate emergency reassessment

• Any drop in GCS, increasing drowsiness, agitation, confusion, or new weakness
• Unequal, dilated, or poorly reactive pupils
• Repeated vomiting, worsening severe headache, seizure
• New abnormal breathing, low oxygen level, bradycardia with hypertension, or unstable BP
• CT showing ongoing expansion, significant midline shift, hydrocephalus, or mass effect
• Inability to maintain airway or control pain/vomiting

Before repatriation, ask the treating team these specific questions

1. What exactly increased on CT? Obtain the SDH thickness, ICH volume/location, midline shift in mm, basal-cistern status, edema, ventricular extension, and whether there is hydrocephalus.
2. Has a neurosurgeon reviewed both scans and documented that surgery is not urgently needed before travel?
3. Is the patient approved for a 7-hour flight by an aeromedical physician, not only by the airline?
4. Is the plan a critical-care air ambulance or a commercial aircraft? With an enlarging untreated intracranial bleed, a routine commercial flight, even with a family member, is not an appropriate substitute for medical transfer.
5. Is there a confirmed receiving ICU/neurosurgical bed and named neurosurgeon in India? CT images and reports should be sent ahead and physically carried too.

If transfer is accepted, minimum safety requirements

• Physician-led critical-care/aeromedical transfer, with continuous monitoring, oxygen, suction, IV infusion pumps, emergency airway capability, and medications for seizure, vomiting, BP control, and raised ICP.
• Frequent GCS and pupil checks during all ground and air segments.
• Head elevated about 30 degrees, neutral neck, avoid agitation/straining and avoid hypoxia or hypotension.
• Continue 3% saline only under the transporting clinician's protocol, with a defined sodium target and monitoring plan. Do not stop, start, or alter the infusion independently.
• Avoid anticoagulants, antiplatelet medicines, NSAIDs, alcohol, and unnecessary sedating medication unless the treating doctor specifically orders them. Any anticoagulant-related coagulopathy should be urgently reversed when applicable.
• Ensure smooth BP control, avoiding both severe hypertension and hypotension. Hematoma expansion is associated with worse outcome, and guideline-based ICH care emphasizes rapid access to neurosurgical/neurocritical capability. AHA ICH guidance

Do not depart, or divert immediately, for

• New headache, vomiting, confusion, sleepiness, agitation, weakness, seizure, speech difficulty, or visual changes
• A fall in GCS from 15
• Unequal or sluggish pupils
• Abnormal breathing, oxygen desaturation, persistent high BP, or bradycardia with hypertension
• Any further CT expansion, significant midline shift, hydrocephalus, or neurosurgical concern

• Why it was started: raised ICP/edema, sodium level, or both
• Latest sodium, chloride, osmolality, kidney function, and fluid balance
• CT findings such as midline shift, edema, mass effect, or hydrocephalus
• Current BP, GCS, pupils, and planned mode of medical transport