Overview
The goal of this observational study is to learn whether ketamine given for procedural analgesia changes intracranial pressure in adult emergency department patients. Intracranial pressure is assessed non-invasively by measuring optic nerve sheath diameter (ONSD) with bedside ultrasonography. The main questions it aims to answer are:
- Does ONSD change after ketamine administration compared with the measurement taken before ketamine?
- Does the change in ONSD differ between patients receiving 0.5 mg/kg and 1 mg/kg ketamine? Participants who receive intravenous ketamine as part of their routine emergency care will have ONSD, vital signs, and pain scores recorded before ketamine administration and at 2, 5, 15, and 30 minutes after administration.
Description
This prospective observational study is conducted in the Emergency Department of Ankara Etlik City Hospital. Adult patients who receive intravenous ketamine for procedural analgesia are enrolled consecutively after written and verbal informed consent. The decision to use ketamine and the dose (0.5 mg/kg or 1 mg/kg) are made by the treating emergency physician as part of routine care; the study does not assign, change, or interfere with any treatment. Patients are grouped according to the ketamine dose they receive.
Optic nerve sheath diameter (ONSD) is measured with bedside ocular ultrasonography immediately before ketamine administration (minute 0) and at 2, 5, 15, and 30 minutes after administration. Systolic and diastolic blood pressure, heart rate, oxygen saturation, body temperature, and pain intensity (Numeric Rating Scale) are recorded at the same time points. Adverse events related to ketamine are recorded during the 30-minute observation period. Ocular ultrasonography is the only study-specific procedure; it is non-invasive and painless. The planned sample size is 160 patients.
Eligibility
Inclusion Criteria:
- Age 18 years or older
- Hemodynamically stable
- Receiving intravenous ketamine for procedural analgesia for any clinical indication
- Written and verbal informed consent
Exclusion Criteria:
- Pregnancy or suspected pregnancy
- History of moderate or severe head trauma
- History of cerebrovascular disease
- Intracranial mass
- Previous intracranial surgery
- Signs of increased intracranial pressure
- Chronic obstructive pulmonary disease
- Hypercapnia
- Porphyria
- Liver failure
- Chronic kidney disease
- Cerebral palsy
- Multiple sclerosis
- Use of antidepressant medication
- Optic neuritis
- Globe rupture
- Glaucoma
- Use of an agent other than ketamine for procedural analgesia
- Known allergy or intolerance to ketamine
- Disorientation, inability to cooperate, or inability to communicate
