Browsing by Author "Dunn, Lauren K"

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    Postoperative Low-Dose Tranexamic Acid After Major Spine Surgery: A Matched Cohort Analysis.
    (Neurospine, 2020-12-31) Dunn, Lauren K; Chen, Ching-Jen; Taylor, Davis G; Esfahani, Kamilla; Brenner, Brian; Luo, Charles; Buell, Thomas J; Spangler, Sarah N; Buchholz, Avery L; Smith, Justin S; Shaffrey, Christopher I; Nemergut, Edward C; Durieux, Marcel E; Naik, Bhiken I

    Objective

    This was a retrospective, cohort study investigating the efficacy and safety of continuous low-dose postoperative tranexamic acid (PTXA) on drain output and transfusion requirements following adult spinal deformity surgery.

    Methods

    One hundred forty-seven patients undergoing posterior instrumented thoracolumbar fusion of ≥ 3 vertebral levels at a single institution who received low-dose PTXA infusion (0.5-1 mg/kg/hr) for 24 hours were compared to 292 control patients who did not receive PTXA. The cohorts were propensity matched based on age, sex, American Society of Anesthesiologist physical status classification, body mass index, number of surgical levels, revision surgery, operative duration, and total intraoperative TXA dose (n = 106 in each group). Primary outcome was 72-hour postoperative drain output. Secondary outcomes were number of allogeneic blood transfusions.

    Results

    There was no significant difference in postoperative drain output in the PTXA group compared to control (660 ± 420 mL vs. 710 ± 490 mL, p = 0.46). The PTXA group received significantly more crystalloid (6,100 ± 3,100 mL vs. 4,600 ± 2,400 mL, p < 0.001) and red blood cell transfusions postoperatively (median [interquartile range]: 1 [0-2] units vs. 0 [0-1] units; incidence rate ratio [95% confidence interval], 1.6 [1.2-2.2]; p = 0.001). Rates of adverse events were comparable between groups.

    Conclusion

    Continuous low-dose PTXA infusion was not associated with reduced drain output after spinal deformity surgery. No difference in thromboembolic incidence was observed. A prospective dose escalation study is warranted to investigate the efficacy of higher dose PTXA.
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    Rotational thromboelastometry-guided transfusion during lumbar pedicle subtraction osteotomy for adult spinal deformity: preliminary findings from a matched cohort study.
    (Neurosurgical focus, 2019-04) Buell, Thomas J; Taylor, Davis G; Chen, Ching-Jen; Dunn, Lauren K; Mullin, Jeffrey P; Mazur, Marcus D; Yen, Chun-Po; Shaffrey, Mark E; Shaffrey, Christopher I; Smith, Justin S; Naik, Bhiken I
    OBJECTIVESignificant blood loss and coagulopathy are often encountered during adult spinal deformity (ASD) surgery, and the optimal intraoperative transfusion algorithm is debatable. Rotational thromboelastometry (ROTEM), a functional viscoelastometric method for real-time hemostasis testing, may allow early identification of coagulopathy and improve transfusion practices. The objective of this study was to investigate the effect of ROTEM-guided blood product management on perioperative blood loss and transfusion requirements in ASD patients undergoing correction with pedicle subtraction osteotomy (PSO).METHODSThe authors retrospectively reviewed patients with ASD who underwent single-level lumbar PSO at the University of Virginia Health System. All patients who received ROTEM-guided blood product transfusion between 2015 and 2017 were matched in a 1:1 ratio to a historical cohort treated using conventional laboratory testing (control group). Co-primary outcomes were intraoperative estimated blood loss (EBL) and total blood product transfusion volume. Secondary outcomes were perioperative transfusion requirements and postoperative subfascial drain output.RESULTSThe matched groups (ROTEM and control) comprised 17 patients each. Comparison of matched group baseline characteristics demonstrated differences in female sex and total intraoperative dose of intravenous tranexamic acid (TXA). Although EBL was comparable between ROTEM versus control (3200.00 ± 2106.24 ml vs 3874.12 ± 2224.22 ml, p = 0.36), there was a small to medium effect size (Cohen's d = 0.31) on EBL reduction with ROTEM. The ROTEM group had less total blood product transfusion volume (1624.18 ± 1774.79 ml vs 2810.88 ± 1847.46 ml, p = 0.02), and the effect size was medium to large (Cohen's d = 0.66). This difference was no longer significant after adjusting for TXA (β = -0.18, 95% confidence interval [CI] -1995.78 to 671.64, p = 0.32). More cryoprecipitate and less fresh frozen plasma (FFP) were transfused in the ROTEM group patients (cryoprecipitate units: 1.24 ± 1.20 vs 0.53 ± 1.01, p = 0.03; FFP volume: 119.76 ± 230.82 ml vs 673.06 ± 627.08 ml, p < 0.01), and this remained significant after adjusting for TXA (cryoprecipitate units: β = 0.39, 95% CI 0.05 to 1.73, p = 0.04; FFP volume: β = -0.41, 95% CI -772.55 to -76.30, p = 0.02). Drain output was lower in the ROTEM group and remained significant after adjusting for TXA.CONCLUSIONSFor ASD patients treated using lumbar PSO, more cryoprecipitate and less FFP were transfused in the ROTEM group compared to the control group. These preliminary findings suggest ROTEM-guided therapy may allow early identification of hypofibrinogenemia, and aggressive management of this may reduce blood loss and total blood product transfusion volume. Additional prospective studies of larger cohorts are warranted to identify the appropriate subset of ASD patients who may benefit from intraoperative ROTEM analysis.
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    The Impact of Alvimopan on Return of Bowel Function After Major Spine Surgery - A Prospective, Randomized, Double-Blind Study.
    (Neurosurgery, 2019-08) Dunn, Lauren K; Thiele, Robert H; Lin, Michelle C; Nemergut, Edward C; Durieux, Marcel E; Tsang, Siny; Shaffrey, Mark E; Smith, Justin S; Shaffrey, Christopher I; Naik, Bhiken I

    Background

    Pain management following major spine surgery requires high doses of opioids and is associated with a risk of opioid-induced constipation. Peripheral mu-receptor antagonists decrease the gastrointestinal complications of perioperative systemic opioid administration without antagonizing the analgesic benefits of these drugs.

    Objective

    To investigate the impact of alvimopan in opioid-naive patients undergoing major spine surgery.

    Methods

    Patients undergoing >3 levels of thoracic and/or lumbar spine surgery were enrolled in this prospective, randomized, double-blind study to receive either alvimopan or placebo prior to and following surgery. Opioid consumption; pain scores; and time of first oral intake, flatus, and bowel movement were recorded.

    Results

    A total of 24 patients were assigned to the active group and 25 were assigned to the placebo group. There was no significant difference in demographics between the groups. Postoperatively, the alvimopan group reported earlier time to first solid intake [median (range): alvimopan: 15 h (3-25) vs placebo: 17 h (3-46), P < .001], passing of flatus [median (range): alvimopan: 22 h (7-63) vs placebo: 28 h (10-58), P < .001], and first bowel movement [median (range): alvimopan: 50 h (22-80) vs placebo: 64 h (40-114), P < .001]. The alvimopan group had higher pain scores (maximum, minimum, and median); however, there was no significant difference between the groups with postoperative opioid use.

    Conclusion

    This study shows that the perioperative use of alvimopan significantly reduced the time to return of bowel function with no increase in postoperative opioid use despite a slight increase in pain scores.
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    Ventilator Mode Does Not Influence Blood Loss or Transfusion Requirements During Major Spine Surgery: A Retrospective Study.
    (Anesthesia and analgesia, 2020-01) Dunn, Lauren K; Taylor, Davis G; Chen, Ching-Jen; Singla, Priyanka; Fernández, Lucas; Wiedle, Christopher H; Hanak, Mark F; Tsang, Siny; Smith, Justin S; Shaffrey, Christopher I; Nemergut, Edward C; Durieux, Marcel E; Blank, Randal S; Naik, Bhiken I

    Background

    Blood loss during adult spinal deformity surgery is multifactorial. Anesthetic-related factors, such as mode of mechanical ventilation, may contribute to intraoperative blood loss. The aim of this study was to determine the influence of ventilator mode and ventilator parameters on intraoperative blood loss and transfusion requirements in patients undergoing prone position spine surgery.

    Methods

    This single-center retrospective study examined electronic medical records of patients ≥18 years of age who underwent elective prone position spine surgery between May 2015 and June 2016. Associations between ventilator mode and ventilator parameters with intraoperative estimated blood loss (EBL), packed red blood cells (PRBCs), fresh-frozen plasma (FFP), cryoprecipitate and platelet transfusions, and subfascial drain output were examined using multiple linear regression models controlling for age, sex, American Society of Anesthesiologist (ASA) physical status score, body mass index (BMI), preoperative blood coagulation parameters and laboratory values, operative levels, cage constructs, osteotomies, transforaminal lumbar interbody fusions, laminectomies, reoperation, spine surgery invasiveness index, and operative time. In a secondary analysis, EBL, blood product transfusions, and postoperative drain output were compared between pressure-controlled ventilation (PCV) and volume-controlled ventilation (VCV) propensity score-matched cohorts.

    Results

    Nine hundred forty-six records were reviewed, and 822 were included in the analysis. After adjusting for confounding, no statistically significant associations were observed between mode of ventilation and intraoperative EBL (estimate, -2; 95% confidence interval [CI], -248 to 245; P = .99) or blood product transfusions (PRBC: estimate, -9; 95% CI, -154 to 135; P = .90; FFP: estimate, -3; 95% CI, -59 to 54; P = .93; cryoprecipitate: estimate, -14; 95% CI, -70 to 43; P = .63; platelets: -7; 95% CI, -39 to 24; P = .64). After propensity score matching (n = 27 per group), no significant differences were observed in EBL (mean difference, 525 mL; 95% CI, -15 to 1065; P = .056) or blood transfusions (PRBC: mean difference, 208 mL; 95% CI, -23 to 439; P = .077; FFP (mean difference, 34 mL; 95% CI, -17 to 84; P = .19); cryoprecipitate (mean difference, 55 mL; 95% CI, -24 to 133; P = .17); or platelets (mean difference, 26 mL; 95% CI, -12 to 64; P = .18) between PCV and VCV groups.

    Conclusions

    In prone position spine surgery, neither mode of mechanical ventilation nor airway pressure is associated with intraoperative blood loss or need for allogeneic transfusion. Use of modern ventilation strategies using lung protective techniques may mitigate differences in blood loss previously observed between PCV and VCV modes.