two male patients were scheduled for reconstruction of their aneurysmal aortic roots . the intraoperative and postoperative management along with the clinical course are detailed in table 1 . these case reports are presented retrospectively ; informed consent was obtained from these patients prior to all interventions . approval to report the cases was received from the university of florida institutional review board , and obtaining informed consent for this report was waived . on the day of surgery , our patients had standard monitors and an arterial catheter was placed . under sterile conditions , while in a sitting position , intrathecal preservative - free morphine was injected via the l2 - 3 interspace midline approach , using a 27-gauge whitacre and introducer needle ( table 1 ) . each patient was then transported to the operating room and after reapplication of monitors , vital sign assessment and preoxygenation anesthesia was induced with propofol and neuromuscular blockade . isoflurane and neuromuscular blockade were used for maintenance . a pulmonary artery catheter and transesophageal echoprobe were inserted , and bispectral monitoring , capnography , and cerebral oximetry were established . in addition , cardiac indices , blood gases , coagulation ( act , inr , aptt , teg ) , neuromuscular blockade , temperature ( esophageal , bladder , rectal ) , and urine output were monitored in the standard fashion . deep hypothermic circulatory arrest was performed by cooling the patients to 18 and placing the head in an ice cap . after rewarming and obtaining adequate indices , cardiopulmonary bypass was discontinued , and protamine was administered for heparin reversal ( act at baseline prior to heparinization ) . once the patients ' hemodynamics and coagulation were stable in the operating room , they were awakened for a neurologic examination and then re - sedated with propofol . our patients remained intubated in the intensive care unit ( icu ) until immediate surgical complications , such as hemorrhage , were excluded . a propofol infusion was used for patient comfort while intubated , and was titrated to allow the patients to interact . extubation , oral intake , and ambulation were determined by the icu provider or cardiac surgeon . studies have shown that a high - dose narcotic regimen does not affect the systemic stress response to surgery . these findings led to an increasing interest in the use of neuraxial techniques , such as intrathecal or epidural drug administration . indeed , local anesthetics and narcotics delivered to the neuraxis are able to attenuate the stress response after cardiac surgery . a prospective randomized study of patients undergoing coronary artery bypass grafting showed significantly better outcomes in regards to supraventricular arrhythmias , respiratory infection , renal failure , and confusion in patients who received a thoracic epidural infusion of bupivacaine and clonidine , compared to that of the control group , who received a general anesthetic and intravenous narcotics . however , that study had some limitations , one being that beta - blockers were allowed . another study by priestly et al .   found improved pain scores and enhanced early extubation , but no effects on arrhythmias , hospital discharge , or overall outcome . nonetheless , both studies provide strong evidence that excellent analgesia can be provided by an epidural technique , even allowing for performing cardiac surgery in awake , nonintubated patients . in our estimation , a significant limitation of the epidural technique is that a catheter has to be placed in patients who are scheduled to receive high - dose heparin , may require immediate postoperative anticoagulation , and could be subject to major alterations of their hemostatic system . thereby , it increases the risk of epidural hematoma formation , which could result in paraplegia . the intrathecal single - shot administration of drugs , such as morphine , offers an elegant alternative in these patients , making catheter placement unnecessary and reducing the risk of hematoma formation . furthermore , both intrathecal and epidural narcotic administration are equal in analgesic potency . this rationale - to use the intrathecal route - proved effective in our patients who were undergoing a complex aortic root reconstruction using cardiopulmonary bypass and circulatory arrest under deep hypothermia , which requires full heparinization . additionally , given the extracorporeal circulation and deep hypothermia , major changes in their hemostatic system and an exaggerated stress response were expected . intrathecal morphine has been extensively studied in cardiac surgery patients , and no reports of spinal hematoma , to our knowledge , have been reported . as in our patients , the majority of published studies have used full heparinization , but with only mild hypothermia ( 28 - 32 ) and no circulatory arrest . a trial of intrathecal morphine in patients undergoing deep hypothermic cardiac arrest has not been reported , and we can only speculate that concerns regarding the possibility of developing a spinal hematoma may have played a role . statistically , the risk of a spinal hematoma following a dural puncture is 1 : 220,000 . the strategy we implemented , the avoiding of full heparinization within two hours after dural puncture , abandoning the puncture if more than three attempts are necessary , and postponing the surgery for 24 hours if a traumatic puncture occurred , is compliant with the literature . the potential necessity to postpone surgery should be discussed and agreed upon by the patient and the surgeon before proceeding with an intrathecal approach . in both of our cases , we are able to attest to the intense and lasting analgesia of intrathecal morphine , as neither of our patients requested narcotics during the first 24 hours of the postoperative period ( table 1 ) . this finding is remarkable even further , as we did not administer supplemental narcotics during surgery in the first patient and only 100 g of fentanyl in the second patient . in addition , administration of narcotics in the postoperative period was left completely up to the icu provider , and was not influenced by the anesthesia team . other studies reported morphine consumption of 21.3 mg in the control group versus 13.6 or 11.7 mg in patients receiving intrathecal morphine . side effects , such as pruritus , which can be severe in up to 1% and mild in up to 30% of patients receiving intrathecal morphine , were not observed in our two patients . we did not assess the effects of intrathecal morphine on the return of function in our two cases , as our investigation was preliminary , but we can state that both of our patients were extubated , ambulating or sitting , and successfully started on oral intake within 24 hours after admission to the icu ( table 1 ) . studies are inconclusive with regard to improved functional outcome after intrathecal morphine administration . there was no improvement in pulmonary function ; however , improvement in the airway clearance and coughing , and ambulation was noted . overall , the medical literature persistently shows a clear benefit of intrathecal morphine in providing excellent and lasting analgesia . in summary , the two cases we have presented with the use of intrathecal morphine , for the first time , in patients undergoing circulatory arrest and deep hypothermia , we observed high quality analgesia without associated side effects . precautions with regard to the risk of hematoma formation , however , have to be followed in these types of patients .
we retrospectively report the first use of intrathecal morphine prior to incision in two male patients undergoing a complex aortic reconstruction , who required complete circulatory arrest under deep hypothermia for intraoperative and postoperative pain control . 
 we administered intrathecal morphine to two male patients undergoing circulatory arrest and deep hypothermia . 
 patients were fully heparinized prior to cardiopulmonary bypass . 
 deep hypothermic circulatory arrest was performed by cooling the patients to 18. following the surgery , the neurologic status was monitored . 
 the management of postoperative pain is a quality standard in health care . during the first 24 hours after surgery 
 , we observed excellent analgesia without the associated side effects , thus , reducing the time required for pain control by the nursing staff . 
 a successful analgetic strategy not only enhances the patient satisfaction , but may improve the postoperative outcome . 
 however , complications , such as increased risk of epidural hematoma formation , are of special concern in cardiac surgery .