Intraoperative Ketamine for Analgesia Post-Coronary Artery Bypass Surgery: A Randomized, Controlled, Double-Blind Clinical Trial.

OBJECTIVES: To determine whether the administration of ketamine during coronary artery bypass grafting (CABG) surgery leads to a reduction in the quantity of opioids required over the first 48 hours after surgery. DESIGN: Randomized, controlled, double-blind clinical trial. SETTING: Single university academic center. PARTICIPANTS: Patients undergoing CABG surgery with a normal left ventricular ejection fraction. INTERVENTIONS: Ketamine administered intravenously as a bolus dose of 0.5 mg/kg before skin incision, followed by an infusion of 0.5 mg/kg/h until the end of surgery. MEASUREMENTS AND MAIN RESULTS: One hundred eighty-three patients were screened, and 80 patients were randomized. Baseline characteristics were similar between the 2 groups. The intervention group received 53.6 mg (95% confidence interval [CI] 47.1-60.1 mg) of morphine equivalents in the first 48 hours after surgery, whereas the placebo group received 55.7 mg (95% CI 48.4-63.1 mg) over the same time period (p = 0.66). No significant difference was noted in morphine equivalents over the first 6, 12, or 24 hours postoperatively or in maximum, minimum, or average pain scores on postoperative days 1 or 2. CONCLUSIONS: The administration of ketamine during CABG surgery did not result in reduced opioid consumption or pain scores postoperatively.

Anatomical Variations of the Vertebral Artery in the Upper Cervical Spine: Clinical Relevance for Procedures Targeting the C1/C2 and C2/C3 Joints.

BACKGROUND AND OBJECTIVES: Accidental breach of the vertebral artery (VA) during the performance of cervical pain blocks can result in significant morbidity. Whereas anatomical variations have been described for the foraminal (V2) segment of the VA, those involving its V3 portion (between the C2 transverse process and dura) have not been investigated and may be of importance for procedures targeting the third occipital nerve or the lateral atlantoaxial joint. METHODS: Five hundred computed tomography angiograms of the neck performed in patients older than 50 years for the management of cerebrovascular accident or cervical trauma (between January 2010 and May 2016) were retrospectively and independently reviewed by 2 neuroradiologists. Courses of the VA in relation to the lateral aspect of the C2/C3 joint and the posterior surface of the C1/C2 joint were examined. For the latter, any medial encroachment of the VA (or one of its branches) was noted. The presence of a VA loop between C1 and C2 and its distance from the upper border of the superior articular process (SAP) of C3 were also recorded. If the VA loop coursed posteriorly, its position in relation to 6 fields found on the lateral aspects of the articular pillars of C2 and C3 was tabulated. RESULTS: At the C1/C2 level, the VA coursed medially over the lateral quarter of the dorsal joint surface in 1% of subjects (0.6% and 0.4% on the left and right sides, respectively; P = 0.998). A VA loop originating between C1 and C2 was found to travel posteroinferiorly over the anterolateral aspect of the inferior articular pillar of C2 in 55.5% of patients on the left and 41.9% on the right side (P < 0.001), as well as over the SAP of C3 in 0.4% of subjects. When present in the quadrant immediately cephalad to the C3 SAP, VA loops coursed within 2.0 ± 1.5 and 3.3 ± 2.5 mm on the left and right sides, respectively, of its superior aspect (P < 0.001). CONCLUSIONS: The VA commonly travels adjacent to areas targeted by third occipital nerve procedures and more rarely over the access point for lateral atlantoaxial joint injections. Modifications to existing techniques may reduce the risk of accidental VA breach.

Antibiotics in the treatment of patients with lower back pain associated with Modic changes: a case series.

PURPOSE: To determine the clinical effect of antibiotic treatment for patients with low back pain and Modic 1 changes. METHODS: This is a retrospective case series of patients treated at the Canadian Forces Health Services Centre in Ottawa and the McGill University Health Centre. Where available, pain, functional, and imaging outcomes in 11 patients treated between 2013 and 2015 were analyzed to determine effect of antibiotic treatment for patients with low back pain and associated Modic 1 changes on magnetic resonance imaging. RESULTS: Conservatively, only 3 of 11 patients met the criteria for improvement for pain and/or function. While a larger proportion improved in the long term, outcomes were not thought to be temporally attributable to antibiotic treatment, as in most cases, ongoing therapy, medications, and/or injections were required. There did not appear to be a correlation between clinical improvement and associated end plate volume involvement for Modic changes. CONCLUSION: Antibiotics for the treatment of low back pain in the context of Modic changes on MRI did not generally provide significant improvement in pain and function for patients in this small cohort. Despite early excitement regarding this treatment, further research is required.

Electrical stimulation of the epidural space using a catheter with a removable stylet.

BACKGROUND AND OBJECTIVES: Electrical stimulation can be used to verify the location of epidural catheters. With the traditional technique, the latter must be primed with saline to allow for electrical conduction: any air lock will, thus, hinder the flow of current. Therefore, we set out to explore an alternative mode of stimulation by use of a catheter containing a removable stylet. This study examines the reliability of this new technique. METHODS: In 71 patients undergoing surgery, a thoracic epidural catheter was inserted preoperatively. Loss of resistance was used to identify the epidural space. The TheraCath was introduced 5 cm into the space and connected to a neurostimulator via a 2-headed alligator clip. The intensity, pulse width, and level of myotomal contractions were recorded upon stimulation of the epidural space. A bolus of lidocaine was then injected and the patient assessed for sensory block to ice. RESULTS: The failure rate in proper epidural catheter placement was 8.5%. Epidural stimulation yielded a mean threshold of 1.90 +/- 1.80 nanocoulombs. A total of 37 catheters produced a unilateral muscular response; however, block to ice was bilateral. When compared with the ice test, the sensitivity, specificity, positive predictive value, and negative predictive value of epidural stimulation with the TheraCath were 92%, 83%, 98%, and 50%, respectively. CONCLUSION: We conclude that the TheraCath, because of the removable stylet, provides effective electrostimulation of the epidural space. Its use was simple and devoid of complications. Nonetheless, further studies are required before implementing its routine use in clinical settings.

Patient controlled i.v. analgesia is an acceptable pain management strategy in morbidly obese patients undergoing gastric bypass surgery. A retrospective comparison with epidural analgesia.

PURPOSE: To examine the hypothesis that pain treatment with patient controlled analgesia (PCA) using iv morphine is a suitable and safe alternative to epidural analgesia in morbidly obese patients undergoing gastric bypass surgery. We retrospectively compared the postoperative periods in all patients undergoing this procedure in our institution between November 1999 and November 2001. METHODS: According to their perioperative pain treatment, patients were assigned to a PCA group (with iv morphine) or an epidural analgesia group, in which patients received either intermittent doses of morphine or continuous infusions of bupivacaine/fentanyl. Study endpoints included quality of pain control, incidence of cardiovascular and respiratory complications, analgesia related side effects, time to ambulation and first flatus, length of hospital stay, and wound infections. RESULTS: Data from 86 patients were analyzed with 40 patients in the PCA group and 46 patients in the epidural group. Groups were similar with respect to age, body mass index, and gender. The type of analgesia did not affect the quality of pain control at rest, the frequency of nausea and pruritus, the time to ambulation and return of gastrointestinal function, and the length of hospital stay. Patients receiving epidural analgesia had a greater risk of wound infection than subjects with PCA (epidural group: 39%, PCA group: 15%, P = 0.01). CONCLUSION: We conclude that in grossly obese patients undergoing gastric bypass surgery PCA with iv morphine is an acceptable strategy for pain management and may confer some advantages when compared to epidural analgesia.