- Dexmedetomidine loading dose 1ug/Kg over 10 minutes then maintenance infusion of 0.5 ug/kg/h (range 0.3 to 0.7 ug/Kg/h), titrate to RASS of -4 (sluggish response to glabellar tap or loud stimulus)
- Fentanyl 1ug/Kg 5 minutes prior to skin infiltration with local anesthetic.
- Once sedated to RASS of -4, local anesthetic given (2ml 0.5 bupivacaine and 2ml 2% lignocaine with adrenaline) at each Burr hole site.
- Taper dexmedetomidine and stop once hemostasis achieved and skin closure commenced.
- Rescue bolus of midazolam 0.5 mg IV to max of 2.5mg given if not adequately sedated or with inadvertent movement during procedure.
Failure – switch to General Anesthesia:
- induction with fentanyl 2ug/kg IV
- thiopentone 3-5mg/kg titrate to LOC
- vecuronium 0.12 mg/Kg or atracurium 0.5mg ?kg
- Maintain anesthesia with 40% O2 in N20 and isoflurane or sevoflurane to MAC of 1
- reverse neuromuscular blockade with neostigmine and glycopyrrolate at end of procedure
Other meds for troubleshooting:
- Bradycardia: atropine 0.6mg IV
- Tachycardia: fluid bolus and esmolol 0.5mg/Ig
- Hypotension: fluid bolus then mephentermine 6mg bolus, repeat to max of 12
- Hypertension: labetalol 10mg bolus
Compared to GA, dexmedetomidine sedation with local anesthesia is:
- safe and effective
- associated with shorter OR time, lesser hemodynamic fluctuations, post-op complications and length of hospital stay.
Surve, Rohini M. et al. “Use Of Dexmedetomidine Along With Local Infiltration Versus General Anesthesia For Burr Hole And Evacuation Of Chronic Subdural Hematoma (CSDH)”. Journal of Neurosurgical Anesthesiology (2016): 1. Web.
AMERICAN SOCIETY OF ANESTHESIOLOGISTS PHYSICAL STATUS CLASSIFICATION
CLASS I No organic, physiological, biochemical or psychiatric disturbance. The pathologic process for which operation is to be performed is localized and is not a systemic disturbance.
CLASS II Mild to moderate systemic disturbance caused either by the condition to be treated or by other pathophysiological processes.
CLASS III Severe systemic disturbance or disease from whatever cause, even though it may not be possible to define the degree of disability with finality.
CLASS IV Severe systemic disorder already life‐threatening, not always correctable by the procedure.
CLASS V Moribund patient who has little chance of survival, but is submitted to the procedure in desperation. CLASS VI Organ donor.
1. Minimal sedation (anxiolysis) A drug‐induced state during which patients respond normally to verbal commands. Although cognitive function and coordination may be impaired, ventilatory and cardiovascular functions are unaffected.
2. Moderate (conscious) sedation/analgesia A drug‐induced depression of consciousness during which patients respond purposefully to verbal commands, either alone or accompanied by light tactile stimulation. No interventions are required to maintain a patent airway, and spontaneous ventilation is adequate. Cardiovascular function is usually maintained. The difference between analgesia and moderate sedation is the intent. With moderate sedation there is the intent to produce an altered mental state, for the performance of a procedure, as opposed to analgesia (for relief of pain without intentional production of altered mental state such as sedation).
3. Deep sedation/analgesia A drug‐induced depression of consciousness during which patients cannot be easily aroused but respond purposefully following repeated or painful stimulation. The ability to independently maintain ventilatory function maybe impaired. Patients may require assistance in maintaining a patent airway and spontaneous ventilation may be inadequate. Cardiovascular function is usually maintained.
4. Anesthesia Consists of general anesthesia and spinal or major regional anesthesia. It does not include local anesthesia. General anesthesia is a drug‐induced loss of consciousness during which patients are not arousable, even by painful stimulation. The ability to independently maintain ventilatory function is often impaired. Patients often require assistance in maintaining a patent airway, and positive pressure ventilation may be required because of depressed spontaneous ventilation or drug‐induced depression of neuromuscular function. Cardiovascular function may be impaired.