Publications

Spinal drain placement to prevent spinal cord ischemia during thoracic aorta surgery is a necessary yet complex undertaking in patients with coagulopathies. Thromboelastography (TEG) can be used as a point-of-care management tool to monitor coagulation status before drain placement and removal. We present 2 cases: a case of a patient with factor VII deficiency and a case of a patient with thrombocytopenia for whom TEG was an important procedural adjunct during coagulopathy reversal. TEG parameters are also discussed to encourage more frequent TEG use as an adjunct during these complex cases.

Ultrasonography (US) proficiency has become a desirable skill for anesthesia providers. It is commonly used in the perioperative arena for establishing peripheral and central vascular access. Establishing intravenous access is one of the most common procedures performed by Certified Registered Nurse Anesthetists (CRNAs) as frontline anesthesia providers. However, there is no structured US training program for CRNAs for vascular access at our institution. We designed and implemented a multimodality US training program specifically for the use of surface US for central and peripheral vascular access for CRNAs. The course was conducted over 2 days and consisted of an online self-paced didactic component, integrated proctored hands-on workshops, and a posttraining examina-tion to quantify knowledge gain. Twenty-five CRNAs attended the course, with significant improvement in knowledge (pretest mean (SD) score = 59.13% (15.74%) vs posttest mean score = 70.0% (9.43%), P = .03). Two weeks after the course, each participant reported that they attempted 1.46 (1.56) ultrasound-guided vascular access procedures on average. Therefore, it is feasible to design short, focused, multimodality training programs for proficiency in the use of surface US for obtaining venous access. The CRNA's proficiency in US is likely to improve efficiency, patient experience, and safety.

BACKGROUND AND OBJECTIVES: Advanced haptic simulators for neuraxial training are expensive, have a finite life, and are not patient specific. We sought to demonstrate the feasibility of developing a custom-made, low-cost, 3-dimensionally printed thoracic spine simulator model from patient computed tomographic scan data. This study assessed the model's practicality, efficiency as a teaching tool, and the transfer of skill set into patient care.

METHODS: A high-fidelity, patient-specific thoracic spine model was used for the study. Thirteen residents underwent a 1-hour 30-minute training session prior to performing thoracic epidural analgesia (TEA) on patients. We observed another group of 14 residents who were exposed to the traditional method of training during their regional anesthesia rotation for thoracic epidural placement. The TEA was placed for patients under the supervision of attending anesthesiologists, who were blinded to the composition of the study and control groups. As a primary outcome, data were collected on successful TEAs, which was defined as a TEA that provided full relief of sensation across the entire surgical area as assessed by both a pinprick and temperature test. Secondary outcomes included whether any assistance from the attending physician was required and failed epidurals.

RESULTS: A total of 27 residents completed the study (14 in the traditional training, 13 in the study group). We found that the residents who underwent training with the simulator had a significantly higher success rate (11 vs 4 successful epidural attempts, P = 0.002) as compared with the traditional training group. The control group also required significantly more assistance from the supervising anesthesiologist compared with the study group (5 vs 1 attempt requiring guidance). The number needed to treat (NNT) for the traditional training group was 1.58 patients over the study period with a 95% confidence interval of 1.55 to 1.61.

CONCLUSIONS: By using patient-specific, 3-dimensionally printed, thoracic spine models, we demonstrated a significant improvement in clinical proficiency as compared with traditional teaching models.

During standard transesophageal echocardiographic examinations in sinus rhythm (SR) patients, the left atrial appendage (LAA) is not routinely assessed with Doppler. Despite having a SR, it is still possible to have irregular activity in the LAA. This situation is even more important for SR patients where assessment of the left atrium is often foregone. We describe a case where we encountered this situation and briefly review how to assess the left atrium and its appendage in such a case scenario.

BACKGROUND: In some institutions, the current blood ordering practice does not discriminate minimally invasive endovascular aneurysm repair (EVAR) from open procedures, with consequent increasing costs and likelihood of blood product wastage for EVARs. This limitation in practice can possibly be addressed with the development of a reliable prediction model for transfusion risk in EVAR patients. We used the American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP) database to create a model for prediction of intraoperative blood transfusion occurrence in patients undergoing EVAR. Afterward, we tested our predictive model on the Vascular Study Group of New England (VSGNE) database.

METHODS: We used the ACS NSQIP database for patients who underwent EVAR from 2011 to 2013 (N = 4709) as our derivation set for identifying a risk index for predicting intraoperative blood transfusion. We then developed a clinical risk score and validated this model using patients who underwent EVAR from 2003 to 2014 in the VSGNE database (N = 4478).

RESULTS: The transfusion rates were 8.4% and 6.1% for the ACS NSQIP (derivation set) and VSGNE (validation) databases, respectively. Hemoglobin concentration, American Society of Anesthesiologists class, age, and aneurysm diameter predicted blood transfusion in the derivation set. When it was applied on the validation set, our risk index demonstrated good discrimination in both the derivation and validation set (C statistic = 0.73 and 0.70, respectively) and calibration using the Hosmer-Lemeshow test (P = .27 and 0.31) for both data sets.

CONCLUSIONS: We developed and validated a risk index for predicting the likelihood of intraoperative blood transfusion in EVAR patients. Implementation of this index may facilitate the blood management strategies specific for EVAR.

OBJECTIVE: Preoperative type and cross are often routinely ordered before elective endovascular aneurysm repair (EVAR), but the cost of this practice is high, and transfusion is rare. We therefore aimed to stratify patients by their risk of transfusion to identify a cohort in whom a type and screen would be sufficient.

METHODS: We queried the targeted vascular module of the National Surgical Quality Improvement Program (NSQIP) for all elective EVARs from 2011 to 2015. We included only infrarenal aneurysms and excluded ruptured aneurysms and patients transfused within 72 hours preoperatively. Two-thirds of the cases were randomly assigned to a model derivation cohort and one third to a validation cohort. We created and subsequently validated a risk model for transfusion within the first 24 hours of surgery (including intraoperatively), using logistic regression.

RESULTS: Between 2011 and 2015, there were 4875 patients who underwent elective infrarenal EVAR, only 221 (4.5%) of whom received a transfusion within 24 hours of surgery. The frequency of transfusion during the study period declined monotonously from 6.5% in 2011 to 3.2% in 2015. The factors independently associated with transfusion were preoperative hematocrit <36% (odds ratio [OR], 3.4 [95% confidence interval, 2.1-5.4]; P < .001), aortic diameter (per centimeter increase: OR, 1.2 [1.03-1.4]; P = .02), preoperative dependent functional status (OR, 2.5 [1.1-5.5]; P = .03), and chronic obstructive pulmonary disease (OR, 1.7 [1.04-2.9]; P = .04). A risk prediction model based on these criteria produced a C statistic of 0.69 in the prediction cohort and 0.76 in the validation cohort and a Hosmer-Lemeshow goodness of fit of 0.62 and 0.14, respectively. A score of <3 of 9, corresponding to a <5% probability of transfusion, would avoid preoperative type and cross in 86% of patients. Of the 4203 patients (86%) with a hematocrit >36%, only 6 (0.1%) had a risk score of >3.

CONCLUSIONS: Perioperative transfusion for EVAR is becoming increasingly uncommon and is predicted well by a transfusion risk score or simply a hematocrit of <36%. Application of this risk score would avoid unnecessary type and cross in the majority of patients, leading to significant savings in both time and cost.

METHODS: Anonymized CT DICOM data was segmented to create a 3D model of the lumbar spine. The 3D model was modified, placed inside a digitally designed housing unit and fabricated on a desktop 3D printer using polylactic acid (PLA) filament. The model was filled with an echogenic solution of gelatin with psyllium fiber. Twenty-two staff anesthesiologists performed a spinal and epidural on the 3D printed simulator and a commercially available Simulab phantom. Participants evaluated the tactile and ultrasound imaging fidelity of both phantoms via Likert-scale questionnaire.

RESULTS: The 3D printed neuraxial phantom cost $13 to print and required 25 hours of non-supervised printing and 2 hours of assembly time. The 3D printed phantom was found to be less realistic to surface palpation than the Simulab phantom due to fragility of the silicone but had significantly better fidelity for loss of resistance, dural puncture and ultrasound imaging than the Simulab phantom.

CONCLUSION: Low-cost neuraxial phantoms with fidelity comparable to commercial models can be produced using CT data and low-cost infrastructure consisting of FLOS software and desktop 3D printers.