Effect of Tranexamic Acid on Blood Loss, D-Dimer, and Fibrinogen Kinetics in Adult Spinal Deformity Surgery.

BACKGROUND: Antifibrinolytics such as tranexamic acid reduce operative blood loss and blood product transfusion requirements in patients undergoing surgical correction of scoliosis. The factors involved in the unrelenting coagulopathy seen in scoliosis surgery are not well understood. One potential contributor is activation of the fibrinolytic system during a surgical procedure, likely related to clot dissolution and consumption of fibrinogen. The addition of tranexamic acid during a surgical procedure may mitigate the coagulopathy by impeding the derangement in D-dimer and fibrinogen kinetics. METHODS: We retrospectively studied consecutive patients who had undergone surgical correction of adult spinal deformity between January 2010 and July 2016 at our institution. Intraoperative hemostatic data, surgical time, estimated blood loss, and transfusion records were analyzed for patients before and after the addition of tranexamic acid to our protocol. Each patient who received tranexamic acid and met inclusion criteria was cohort-matched with a patient who underwent a surgical procedure without tranexamic acid administration. RESULTS: There were 17 patients in the tranexamic acid cohort, with a mean age of 60.7 years, and 17 patients in the control cohort, with a mean age of 60.9 years. Estimated blood loss (932 ± 539 mL compared with 1,800 ± 1,029 mL; p = 0.005) and packed red blood-cell transfusions (1.5 ± 1.6 units compared with 4.0 ± 2.1 units; p = 0.001) were significantly lower in the tranexamic acid cohort. In all single-stage surgical procedures that met inclusion criteria, the rise of D-dimer was attenuated from 8.3 ± 5.0 µg/mL in the control cohort to 3.3 ± 3.2 µg/mL for the tranexamic acid cohort (p < 0.001). The consumption of fibrinogen was 98.4 ± 42.6 mg/dL in the control cohort but was reduced in the tranexamic acid cohort to 60.6 ± 35.1 mg/dL (p = 0.004). CONCLUSIONS: In patients undergoing spinal surgery, intravenous administration of tranexamic acid is effective at reducing intraoperative blood loss. Monitoring of D-dimer and fibrinogen during spinal surgery suggests that tranexamic acid impedes the fibrinolytic pathway by decreasing consumption of fibrinogen and clot dissolution as evidenced by the reduced formation of D-dimer. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Anesthesia Exposure and Risk of Dementia and Alzheimer's Disease: A Prospective Study.

OBJECTIVES: To evaluate the associations between anesthesia and dementia or Alzheimer's disease (AD) risk using prospectively collected data. DESIGN: Cohort study. PARTICIPANTS: Community-dwelling members of the Adult Changes in Thought cohort aged 65 and older and free of dementia at baseline (N = 3,988). MEASUREMENTS: Participants self-reported all prior surgical procedures with general or neuraxial (spinal or epidural) anesthesia at baseline and reported new procedures every 2 years. People undergoing high-risk surgery with general anesthesia, other surgery with general anesthesia, and other surgery with neuraxial anesthesia exposures were compared with those with no surgery and no anesthesia. Cox proportional hazards models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for dementia and AD associated with time-varying lifetime and recent (past 5 years) anesthesia exposures. RESULTS: At baseline, 254 (6%) people reported never having anesthesia; 248 (6%) had had one or more high-risk surgeries with general anesthesia, 3,363 (84%) had had one or more other surgeries with general anesthesia, and 123 (3%) had had one or more surgeries with neuraxial anesthesia. High-risk surgery with general anesthesia was not associated with greater risk of dementia (HR = 0.86, 95% CI = 0.58-1.28) or AD (HR = 0.95, 95% CI = 0.61-1.49) than no history of anesthesia. People with any history of other surgery with general anesthesia had a lower risk of dementia (HR = 0.63, 95% CI = 0.46-0.85) and AD (HR = 0.65, 95% CI = 0.46-0.93) than people with no history of anesthesia. There was no association between recent anesthesia exposure and dementia or AD. CONCLUSION: Anesthesia exposure was not associated with of dementia or AD in older adults.

The Prevention of Delirium and Complications Associated with Surgical Treatments (PODCAST) study: protocol for an international multicentre randomised controlled trial.

INTRODUCTION: Postoperative delirium is one of the most common complications of major surgery, affecting 10-70% of surgical patients 60 years and older. Delirium is an acute change in cognition that manifests as poor attention and illogical thinking and is associated with longer intensive care unit (ICU) and hospital stay, long-lasting cognitive deterioration and increased mortality. Ketamine has been used as an anaesthetic drug for over 50 years and has an established safety record. Recent research suggests that, in addition to preventing acute postoperative pain, a subanaesthetic dose of intraoperative ketamine could decrease the incidence of postoperative delirium as well as other neurological and psychiatric outcomes. However, these proposed benefits of ketamine have not been tested in a large clinical trial. METHODS: The Prevention of Delirium and Complications Associated with Surgical Treatments (PODCAST) study is an international, multicentre, randomised controlled trial. 600 cardiac and major non-cardiac surgery patients will be randomised to receive ketamine (0.5 or 1 mg/kg) or placebo following anaesthetic induction and prior to surgical incision. For the primary outcome, blinded observers will assess delirium on the day of surgery (postoperative day 0) and twice daily from postoperative days 1-3 using the Confusion Assessment Method or the Confusion Assessment Method for the ICU. For the secondary outcomes, blinded observers will estimate pain using the Behavioral Pain Scale or the Behavioral Pain Scale for Non-Intubated Patients and patient self-report. ETHICS AND DISSEMINATION: The PODCAST trial has been approved by the ethics boards of five participating institutions; approval is ongoing at other sites. Recruitment began in February 2014 and will continue until the end of 2016. Dissemination plans include presentations at scientific conferences, scientific publications, stakeholder engagement and popular media. REGISTRATION DETAILS: The study is registered at clinicaltrials.gov, NCT01690988 (last updated March 2014). The PODCAST trial is being conducted under the auspices of the Neurological Outcomes Network for Surgery (NEURONS). TRIAL REGISTRATION NUMBER: NCT01690988 (last updated December 2013).

The Seattle Spine Team Approach to Adult Deformity Surgery: A Systems-Based Approach to Perioperative Care and Subsequent Reduction in Perioperative Complication Rates.

STUDY DESIGN: Retrospective consecutive case review pre- and postintervention. OBJECTIVES: Characterize the effects of the intervention. SUMMARY OF BACKGROUND DATA: Complication rates in adult spinal deformity surgery are unacceptable. System approaches are necessary to increase patient safety. This group reported on the dual-attending surgeon approach, a live multidisciplinary preoperative screening conference, and the intraoperative protocol for the management of coagulopathy. The outcomes were demonstrated by complication rates before and after the institution of this protocol. METHODS: Forty consecutive patients in Group A were managed without the 3-pronged approach. A total of 124 consecutive patients in Group B had a dual-attending surgeon approach, were presented and cleared by a live multidisciplinary preoperative conference, and were managed according to the intraoperative protocol. RESULTS: Group A had an average age of 62 years (range, 39-84 years). Group B had an average age of 64 years (range, 18-84 years). Most patients in both groups had fusions from 9 to 15 levels. Complication rates in Group B were significantly lower (16% vs. 52%) (p < .001). Group B showed significantly lower return rates to the operating room during the perioperative 90-day period (0.8% vs. 12.5%) (p < .001). Group B also had lower rates of wound infection requiring debridement (1.6% vs. 7.5%), lower rates of deep vein thrombosis/pulmonary embolism (3.2% vs. 10%), and lower rates of postoperative neurological complications (0.5% vs. 2.5%) (not significant). Group B had significantly lower rates of urinary tract infection requiring antibiotics (9.7% vs. 32.5%) (p < .001). CONCLUSIONS: These data suggests that a team approach consisting of a dual-attending surgeon approach in the operating room, a live preoperative screening conference, and an intraoperative protocol for managing coagulopathy will significantly reduce perioperative complication rates and enhance patient safety in patients undergoing complex spinal reconstructions for adult spinal deformity.

Effect of chronic ß-blockade on the utility of an epinephrine-containing test dose to detect intravascular injection in nonsedated patients.

BACKGROUND AND OBJECTIVES: A test dose containing epinephrine is routinely used during epidural blockade to detect accidental intravenous needle or catheter placement before the administration of local anesthetics to avert local anesthetic systemic toxicity. ß-Blocker therapy may interfere with the expected hemodynamic response from an intravascular injection. This study describes a cohort of 24 patients and their response to an epinephrine test dose (ie, if expected increased heart rates during test-dose administration are valid in this population.) METHODS: Twenty-four nonsedated, chronically ß-blocked patients were enrolled in a prospective, order-randomized, crossover, double-blind study with injections of both placebo and a 15-µg epinephrine test dose in each individual. After injection into a peripheral vein, we observed blood pressure and pulse rate for 5 minutes, injected the other remaining solution (placebo or epinephrine), and observed hemodynamic parameters in the same fashion. RESULTS: Epinephrine raised the heart rate 17.8 beats per minute (bpm) (95% confidence interval [CI], 15.5-20.1) versus placebo 2.0 bpm (95% CI, - 0.3-4.3 P < 0.001) and the systolic blood pressure 23 mm Hg (95% CI, 17.2-28.9) versus placebo 4.4 (95% CI, - 1.5-10.3); P < 0.001 in our chronically ß-blocked population. A threshold increase of 20 bpm yielded a sensitivity of 37.5% (95% CI, 18.8%-59.4%) and specificity of 100% (95% CI, 85.8%-100%). Revising a threshold to include a change of 10 bpm or increase in systolic blood pressure of 15 mm Hg or greater yielded 100% (95% CI, 85.8%-100%) sensitivity and 87.5% (95% CI, 67.6%-97.3%) specificity. CONCLUSIONS: Epinephrine test-dose administration in nonsedated, chronically ß-blocked patients cannot distinguish intravenous injection at the classic threshold increase of 20 bpm. The response in individuals is varied, and thresholds for a positive test need revising for this population of patients on therapeutic ß-blockers.

Does a paresthesia during spinal needle insertion indicate intrathecal needle placement?

BACKGROUND AND OBJECTIVES: Paresthesias are relatively common during spinal needle insertion, however, the clinical significance of the paresthesia is unknown. A paresthesia may result from needle-to-nerve contact with a spinal nerve in the epidural space, or, with far lateral needle placement, may result from contact with a spinal nerve within the intervertebral foramen. However, it is also possible and perhaps more likely, that paresthesias occur when the spinal needle contacts a spinal nerve root within the subarachnoid space. This study was designed to test this latter hypothesis. METHODS: Patients (n = 104) scheduled for surgery under spinal anesthesia were observed during spinal needle insertion. If a paresthesia occurred, the needle was fixed in place and the stylet removed to observe whether cerebrospinal fluid (CSF) flowed from the hub. The presence of CSF was considered proof that the needle had entered the subarachnoid space. RESULTS: Paresthesias occurred in 14/103 (13.6%) of patients; 1 patient experienced a paresthesia twice. All paresthesias were transient. Following a paresthesia, CSF was observed in the needle hub 86.7% (13/15) of the time. CONCLUSIONS: Our data suggest that the majority of transient paresthesias occur when the spinal needle enters the subarachnoid space and contacts a spinal nerve root. Therefore, when transient paresthesias occur during spinal needle placement it is appropriate to stop and assess for the presence of CSF in the needle hub, rather than withdraw and redirect the spinal needle away from the side of the paresthesia as some authors have suggested.