To pretreat or not to pretreat: prophylactic anticholinergic administration before dexmedetomidine in pediatric imaging. (Betters)

Subramanyam R, et al. To pretreat or not to pretreat: prophylactic anticholinergic administration before dexmedetomidine in pediatric imaging. Anesth Analg. 2015 Aug;121(2):479-85.

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BACKGROUND: Dexmedetomidine (Dex) appears to be very effective as a sole sedative for pediatric imaging when used at high doses, but at an increased risk of transient hypertension, hypotension, and bradycardia. There are no clinical evidence/guidelines to guide anesthesia providers as to whether patients should be pretreated with ananticholinergic. The aim of this study was to demonstrate the changes in hemodynamic parameters after Dex sedation attributed to receiving or not receiving an anticholinergic pretreatment and compare for any differences or similarities. A subgroups analysis was performed in children with Down syndrome (DS).

METHODS: In this retrospective descriptive study, we reviewed the records of 163 children receiving Dex anesthesia during MRI studies. Data analyzed included demographics, history of DS, and hemodynamics (heart rate [HR], systolic blood pressure [SBP], and diastolic blood pressure [DBP]) following Dex loading and infusion and the administration of an anticholinergic (atropine or glycopyrrolate).

RESULTS: The mean age was 94.5 months, and 52 (32%) patients had DS. The generalized linear mixed-effects regression model showed a significant reduction in HR and SBP in all patients when no anticholinergic was administered compared with when it was administered. There was no significant change with DBP. During the scan period, the HR of the no-anticholinergic group decreased 26.6%, whereas that of the anticholinergic group decreased by only 16.7% from baseline (P < 0.01). The maximal SBP increased by a significantly greater percentage, compared with baseline, in the anticholinergic group in comparison with the no-anticholinergic group (20.2% vs 10.4%, respectively; P = 0.02). In the DS group, the difference in the maximal SBP change during the scan period was exaggerated, with a percentage increase that was 36 times larger in the anticholinergic group compared with the no-anticholinergic group (22% vs 0.6%, respectively; P< 0.01).

CONCLUSIONS: Administration of a prophylactic anticholinergic with Dex shows no advantage other than a transient clinically insignificant increase in HR and SBP, and it may precipitate transient exaggerated SBP in more patients compared with not using a prophylactic anticholinergic.

The association of serum vitamin D concentration with serious complications after noncardiac surgery. (Vats)

Turan A, Hesler BD, You J, Saager L, Grady M, Komatsu R, Kurz A, Sessler DI. The association of serum vitamin D concentration with serious complications after noncardiac surgery. Anesth Analg. 2014 Sep;119(3):603-12.

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BACKGROUND: Vitamin D deficiency is a global health problem. Epidemiological studies demonstrate that vitamin D is both cardioprotective and neuroprotective. Vitamin D also plays a substantial role in innate and acquired immunity. Our goal was to evaluate the association of serum vitamin D concentration on serious postoperative complications and death in noncardiac surgical patients.

METHODS: We retrospectively analyzed the data of 3509 patients who had noncardiac surgery at the Cleveland Clinic Main Campus and had a serum vitamin D measurement. The relationship between serum vitamin D concentration and all-cause in-hospital mortality, in-hospital cardiovascular morbidity, and serious in-hospital infections was assessed as a common effect odds ratio (OR) by using a multivariate generalized estimating equation model with adjustment for demographic, medical history variables, and type and duration of surgery.

RESULTS: Higher vitamin D concentrations were associated with decreased odds of in-hospital mortality/morbidity (P = 0.003). There was a linear reduction of the corresponding common effect odds ratio (OR 0.93, 95% confidence interval, 0.88-0.97) for severe in-hospital outcomes for each 5 ng/mL increase in vitamin D concentration over the range from 4 to 44 ng/mL. In addition, we found that the odds versus patients with vitamin D <13 ng/mL (i.e., 1st quintile) were significantly lower in patients with vitamin D 13-20, 20-27, 27-36, and > 36 ng/mL (i.e., 2nd-5th quintiles); the corresponding estimated ORs were 0.65 (99% confidence interval, 0.43-0.98), 0.53 (0.35-0.80), 0.44 (0.28-0.70), and 0.49 (0.31-0.78), respectively. However, there was no statistically significant difference among individual quintiles >13 ng/mL.

CONCLUSIONS: Vitamin D concentrations were associated with a composite of in-hospital death, serious infections, and serious cardiovascular events in patients recovering from noncardiac surgery. While causality cannot be determined from our retrospective analysis, the association suggests that a large randomized trial of preoperative vitamin D supplementation and postoperative outcomes is warranted.

Length of red cell unit storage and risk for delirium after cardiac surgery. (Pham)

Brown CH 4th, Grega M, Selnes OA, McKhann GM, Shah AS, LaFlam A, Savage WJ,
Frank SM, Hogue CW, Gottesman RF. Length of red cell unit storage and risk for
delirium after cardiac surgery. Anesth Analg. 2014 May 22. [Epub ahead of print]

BACKGROUND: The time that red cell units are stored before transfusion may be associated with postoperative complications, although the evidence is conflicting. However, the association between the length of red cell unit storage and postoperative delirium has not been explored. We hypothesized that the length of storage of transfused red cell units would be associated with delirium after cardiac surgery.

METHODS: We conducted a case-control study in which patients undergoing coronary artery bypass, valve, or ascending aorta surgery with cardiopulmonary bypass at Johns Hopkins from 2005 to 2011 were eligible for inclusion. Patients were excluded if they did not receive red cell units, received >4 red cell units during hospitalization, received any transfusion after the first postoperative day, or received red cell units that were not exclusively stored for ≤14 days or >14 days. Eighty-seven patients met transfusion-related inclusion criteria and developed postoperative delirium. Controls who did not develop delirium were selected from the same source population of eligible patients and were matched 1:1 based on age (± 5 years), 2- to 2.5-year band of date of surgery, and surgical procedure. For each patient, we calculated the average storage duration of all transfused red cell units. The primary outcome was odds of delirium in patients who were transfused red cell units with exclusive storage duration >14 days compared with that of ≤14 days. Secondary outcomes were odds of delirium with each increasing day of average red cell unit storage duration. We used conditional multivariable regression to test our hypotheses.

RESULTS: In conditional multivariable analysis of 87 case-control pairs, there was no difference in the odds of patients developing delirium if they were transfused red cell units with an exclusive storage age >14 days compared with that ≤14 days (odds ratio [OR] 1.83; 95% confidence interval, 0.73-4.58, P=0.20). Each additional day of average red cell unit storage beyond 14 days was associated with a 1.01- to 1.13-fold increase in the odds of postoperative delirium (OR, 1.07; P=0.03). Each additional day of average storage beyond 21 days was associated with a 1.02- to 1.23-fold increase in the odds of postoperative delirium (OR, 1.12; P=0.02).

CONCLUSIONS: Transfusion of red cell units that have been stored for >14 days is not associated with increased odds of delirium. However, each additional day of storage >14 or 21 days may be associated with increased odds of postoperative delirium in patients undergoing cardiac surgery. More research is needed to further characterize the association between delirium and storage duration of transfused red cell units.

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The hemodynamic response to dexmedetomidine loading dose in children with and without pulmonary hypertension. (Kamat)

Friesen RH, Nichols CS, Twite MD, Cardwell KA, Pan Z, Pietra B, Miyamoto SD, Auerbach SR, Darst JR, Ivy DD. The hemodynamic response to dexmedetomidine loading dose in children with and without pulmonary hypertension. Anesth Analg. 2013 Oct;117(4):953-9.

BACKGROUND: Dexmedetomidine, an α-2 receptor agonist, is widely used in children with cardiac disease. Significant hemodynamic responses, including systemic and pulmonary vasoconstriction, have been reported after dexmedetomidine administration. Our primary goal of this prospective, observational study was to quantify the effects of dexmedetomidine initial loading doses on mean pulmonary artery pressure (PAP) in children with and without pulmonary hypertension.

METHODS: Subjects were children undergoing cardiac catheterization for either routine surveillance after cardiac transplantation (n = 21) or pulmonary hypertension studies (n = 21). After anesthetic induction with sevoflurane and tracheal intubation, sevoflurane was discontinued and anesthesia was maintained with midazolam 0.1 mg/kg IV (or 0.5 mg/kg orally preoperatively) and remifentanil IV infusion 0.5 to 0.8 μg/kg/min. Ventilation was mechanically controlled to maintain Pco2 35 to 40 mm Hg. When end-tidal sevoflurane was 0% and fraction of inspired oxygen (Fio2) was 0.21, baseline heart rate, mean arterial blood pressure, PAP, right atrial pressure, pulmonary artery occlusion pressure, right ventricular end-diastolic pressure, cardiac output, and arterial blood gases were measured, and indexed systemic vascular resistance, indexed pulmonary vascular resistance, and cardiac index were calculated. Each subject then received a 10-minute infusion of dexmedetomidine of 1 μg/kg, 0.75 μg/kg, or 0.5 μg/kg. Measurements and calculations were repeated at the conclusion of the infusion.

RESULTS: Most hemodynamic responses were similar in children with and without pulmonary hypertension. Heart rate decreased significantly, and mean arterial blood pressure and indexed systemic vascular resistance increased significantly. Cardiac index did not change. A small, statistically significant increase in PAP was observed in transplant patients but not in subjects with pulmonary hypertension. Changes in indexed pulmonary vascular resistance were not significant.

CONCLUSION: Dexmedetomidine initial loading doses were associated with significant systemic vasoconstriction and hypertension, but a similar response was not observed in the pulmonary vasculature, even in children with pulmonary hypertension. Dexmedetomidine does not appear to be contraindicated in children with pulmonary hypertension.

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The impact of video laryngoscopy use during urgent endotracheal intubation in the critically ill. (Chandler)

Anesth Analg. 2013 Jul;117(1):144-9. PMID: 23687228

BACKGROUND: The video laryngoscope (VL) has been shown to improve laryngoscopic views and first-attempt success rates in elective operating room and simulated tracheal intubations compared with the direct laryngoscope (DL). However, there are limited data on the effectiveness of the VL compared with the DL in urgent endotracheal intubations (UEIs) in the critically ill. We assessed the effectiveness of using a VL as the primary intubating device during UEI in critically ill patients when performed by less experienced operators.

METHODS: We compared success rates of UEIs performed by Pulmonary and Critical Care Medicine (PCCM) fellows in the medical intensive care unit and medical or surgical wards. A cohort of PCCM fellows using GlideScope VL as the primary intubating device was compared with a historical cohort of PCCM fellows using a traditional Macintosh or Miller blade DL. The primary measured outcome was first-attempt intubation success rate. Secondary outcomes included total number of attempts required for successful tracheal intubation, rate of esophageal intubation, need for supervising attending intervention, duration of intubation sequence, and incidence of hypoxemia and hypotension.

RESULTS: There were 138 UEIs, with 78 using a VL and 50 using a DL as the primary intubating device. The rate of first-attempt success was superior with the VL as compared with the DL (91% vs 68%, P < 0.01). The rate of intubations requiring ≥3 attempts (4% vs 20%, P < 0.01), unintended esophageal intubations (0% vs 14%, P < 0.01), and the average number of attempts required for successful tracheal intubation (1.2 ± 0.56 vs 1.7 ± 1.1, P < 0.01) all improved significantly with use of the VL compared with the DL.

CONCLUSIONS: UEI using a VL as the primary device improved intubation success and decreased complications compared with a DL when PCCM fellows were the primary operators. These data suggest that the VL should be used as the primary device when urgent intubations are performed by less experienced operators.

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Case report: profound hypotension after anesthetic induction with propofol in patients treated with rifampin. (Chandler)

Anesth Analg. 2013 Jul;117(1):61-4. PMID: 23687230

Rifampin is commonly used for the treatment of tuberculosis and staphylococcal infections, as well as for prevention of infection in cardiac valve and bone surgeries. We report a case of profound hypotension after anesthesia induction with propofol in a patient who was treated with two 600 mg doses of rifampin for prophylaxis of infection before surgery. In a retrospective case-control study of 75 patients, we confirmed this potentially serious drug-drug interaction. After rifampin, there was a significant and prolonged arterial blood pressure reduction when patients received propofol, but not thiopental.

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