High Spinal Anesthesia and the Incidence of Delirium After Cardiac Surgery

High Spinal Anesthesia and the Incidence of Delirium After Cardiac Surgery: a Randomized-controlled Feasibility Trial

This is a feasibility study to determine if enough patients undergoing elective or urgent cardiac surgery, can be enrolled in a study where patients are randomized to receive high spinal anesthesia as an adjunct to general anesthesia for their cardiac surgery. The primary clinical outcome will be the incidence of post-operative delirium.

Intervention

Patients will be randomized to either general anesthesia (GA) or HSA + GA.

1. Spinal group: will receive high spinal anesthesia with hyperbaric bupivacaine (0.3 to 0.6 mgs/kg) + preservative free morphine (3 mcg/kg).
2. Standard intraoperative monitors will include ECG, pulse oximetry, end-tidal CO2 and anesthetic gas measurement, quantitative EEG monitoring (BIS monitor), arterial line, central venous pressure line and any other monitor as clinically indicated.
3. Conduct of the general anesthetic will not be protocolized. It will be a pragmatic study. The attending anesthesiologist will attempt to have a BIS score of 20- 40 during the operation.
4. Intraoperative physiological data (mean blood pressure, end-tidal anesthetic gas concentrations, BIS score) will be recorded and downloaded to a laptop computer using the Trend Face Solo acquisition system for subsequent analysis.
5. The routine postoperative care map for the postoperative cardiac intensive care unit (ICCS) will be followed.
6. All patients will be assessed by the study investigator for presence/absence of delirium on postoperative days 1,2 & 3, as well as routine nursing assessment by the delirium assessment tool CAM-ICU, routinely done by nursing staff. Chart reviews will be conducted to confirm any additional incidence of delirium.
7. All patients will be contacted at one and three months after surgery and asked to complete a ten-minute survey (Postop QoR-15 questionnaire) assessing their quality of recovery.

Inclusion Criteria:

• Adult (>18 years old) patients
• Undergoing elective or urgent cardiac surgical procedures with cardiopulmonary bypass

Exclusion Criteria:

• Contraindications to spinal anesthesia such as active anticoagulation, clopidogrel within 7 days of surgery, ticagrelor within 3 days of surgery and all other contraindications to lumbar puncture
• Pre-existing psychiatric diagnoses such as schizophrenia or manic-depressive disorder
• Complex aortic surgery (> hemi-arch repair, descending thoracic surgery)
• Difficult airway requiring an awake intubation
• BMI > 50