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. Spinal group: will receive high spinal anesthesia with hyperbaric bupivacaine (0.3 to 0.6 mgs/kg) + preservative free morphine (3 mcg/kg). 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. 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. 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. The routine postoperative care map for the postoperative cardiac intensive care unit (ICCS) will be followed. 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. 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.

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. The data collectors will not be aware whether the patient had a spinal anesthetic or not.

Spinal group: will receive high spinal anesthesia with hyperbaric bupivacaine (0.3 to 0.6 mgs/kg) + preservative free morphine (3 mcg/kg). 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. 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.

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. 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.

Spinal group: will receive high spinal anesthesia with hyperbaric bupivacaine (0.3 to 0.6 mgs/kg) + preservative free morphine (3 mcg/kg).

In order to assess protocol adherence (%), in patients randomized to spinal anesthesia, an 80% success rate in establishing a spinal anesthetic will be considered as protocol adherence.

In order to assess protocol adherence (%), completion of 90% of scheduled delirium assessments will be considered protocol adherence.

Duration of delirium (days) as assessed by the number of positive Confusion Assessment Method (CAM) as assessed by study investigator

Duration of delirium (days) as assessed by the number of positive CAM Scores as assessed by nursing/physicians (by chart review).

Duration of delirium (days) as assessed by the number of positive CAM scores as assessed by study investigator from post-operative day 6 to post-operative day 14 or discharge from hospital

Duration of delirium (days) as assessed by the number of positive CAM scores as assessed by nursing/physicians (by chart review) from post-operative day 6 to discharge from hospital

Incidence (%) and total dose of haloperidol, in milligrams, for treatment of agitation as ordered by attending medical staff from day of surgery to discharge from hospital

Incidence (%) and total dose of quetiapine, in milligrams, for treatment of agitation as ordered by attending medical staff from day of surgery to discharge from hospital.

Incidence (%) and total dose of risperidone, in milligrams, for treatment of agitation as ordered by attending medical staff from day of surgery to discharge from hospital.

Incidence (%) of use of dexmedetomidine infusions, for treatment of agitation as ordered by attending medical staff from day of surgery to discharge from the intensive care unit.

Day of surgery until post-operative day 5 or discharge from the intensive care unit whichever comes first..

VAS pain scores (visual analog score) (0 is no pain, 10 is the worst pain possible) at rest for 3 days post-operatively.

VAS pain scores (0 is no pain, 10 is the worst pain possible) with deep breathing for 3 days post-operatively.

Total hydromorphone use including intravenous and oral administration will be recorded for the first 48 hours postoperatively. Hydromorphone totals will be converted to morphine equivalents using MD Calcs algorithm (https://www.mdcalc.com/morphine-milligram-equivalents-mme-calculator).

Total fentanyl use including intravenous and oral administration will be recorded for the first 48 hours postoperatively. Fentanyl totals will be converted to morphine equivalents using MD Calcs algorithm (https://www.mdcalc.com/morphine-milligram-equivalents-mme-calculator).

Total codeine use including intravenous and oral administration will be recorded for the first 48 hours postoperatively. Codeine totals will be converted to morphine equivalents using MD Calcs algorithm (https://www.mdcalc.com/morphine-milligram-equivalents-mme-calculator).

Total morphine use, in milligrams, including intravenous and oral administration will be recorded for the first 48 hours postoperatively.

Mean intraoperative bispectral index (BIS). The BIS scale range is from 0 to 100, with 0 representing no measurable electrical brain activity and 100 the electrical activity of an awake, conscious individual. Currently BIS scores are attempted to be kept between 20 and 40 during surgery to ensure adequate depth of anesthesia.

Total dose of intraoperative sufentanil in micrograms. Sufentanil dosage will be converted to morphine equivalents using the MD Calcs algorithm (https://www.mdcalc.com/morphine-milligram-equivalents-mme-calculator)

Total dose of intraoperative hydromorphone in milligrams. Hydromorphone doses will be converted to morphine equivalents using the MD Calcs algorithm (https://www.mdcalc.com/morphine-milligram-equivalents-mme-calculator)

Total RBC administered (units) both intraoperatively, and postoperatively until post-operative day 3..

Total units of platelets administered (adult doses of platelets ) both intraoperatively, and postoperatively until post-operative day 3

Incidence of use of either norepinephrine, phenylephrine or vasopressin at 12 hours postoperatively (%)

Incidence of use of norepinephrine, phenylephrine or vasopressin administered at 24 hours postoperatively (%)

Incidence of norepinephrine, phenylephrine or vasopressin use longer than 24 hours postoperatively (%)

Incidence of re-admission to ICU for any reason from post-operative day 2 to post-operative day 14 or discharge from hospital (%)

Incidence of major medical complications (%) defined as one or more of: a. Atrial fibrillation b. Pneumonia c. Acute kidney injury (defined as a doubling of pre-operative creatinine) d. Need for dialysis e. Wound infection f. Stroke g. Other

Postoperative quality of life score (Postop QoR-15) will be used to assess quality of recovery at one month postoperatively. The Post QoR-15 scale ranges from 0 to 150, with 0 representing the poorest quality of recovery and 150 the best quality of recovery.

Postoperative quality of life score (Postop QoR-15) will be used to assess quality of recovery at three month postoperatively. The Post QoR-15 scale ranges from 0 to 150, with 0 representing the poorest quality of recovery and 150 the best 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