Perioperative Plasma in Addition to Red Blood Cell Transfusions Are Associated With Increased Venous Thromboembolism Risk Postoperatively.

BACKGROUND: Perioperative red blood cell (RBC) transfusions increase venous thromboembolic (VTE) events. Although a previous study found that plasma resuscitation after trauma was associated with increased VTE, the risk associated with additional perioperative plasma is unknown. METHODS: A US claims and EHR database (TriNetX Diamond Network) was queried. We compared surgical patients who received perioperative plasma and RBC to patients who received perioperative RBC but not plasma. Subanalyses included (1) all surgeries (n = 48,580) and (2) cardiovascular surgeries (n = 38,918). Propensity score matching was performed for age at surgery, ethnicity, race, sex, overweight and obesity, type 2 diabetes, disorders of lipoprotein metabolism, essential hypertension, neoplasms, nicotine dependence, coagulopathies, sepsis, chronic kidney disease, liver disease, nonsteroidal anti-inflammatory analgesics, platelet aggregation inhibitors, anticoagulants, hemoglobin level, outpatient service utilization, and inpatient services; surgery type was included for "all surgeries" analyses. Outcomes included 30-day mortality, postoperative VTE, pulmonary embolism (PE), and disseminated intravascular coagulation (DIC). RESULTS: After matching the surgical cohorts, compared to only RBC, plasma + RBC was associated with higher risk of postoperative mortality (4.52% vs 3.32%, risk ratio [RR]: 1.36 [95% confidence interval, 1.24-1.49]), VTE (3.92% vs 2.70%, RR: 1.36 [1.24-1.49]), PE (1.94% vs 1.33%, RR: 1.46 [1.26-1.68]), and DIC (0.96% vs 0.35%, RR: 2.75 [2.15-3.53]). Among perioperative cardiovascular patients, adding plasma to RBC transfusion was associated with similar increased risk. CONCLUSIONS: When compared with perioperative RBC transfusion, adding plasma was associated with increased 30-day postoperative mortality, VTE, PE, and DIC risk among surgical and cardiovascular surgical patients. Reducing unnecessary plasma transfusion should be a focus of patient blood management to improve overall value in health care.

Dose-dependent effects of red blood cell transfusion and case mix index on venous thromboembolic events in spine surgery.

BACKGROUND AND OBJECTIVES: Venous thromboembolic (VTE) events represent a major source of morbidity and mortality in spine surgery. Our goal was to assess whether a dose-response relationship exists between red blood cell (RBC) transfusion and postoperative VTE events among spine surgery patients. MATERIALS AND METHODS: A total of 786 spine surgery patients at a single institution who received at least 1 RBC unit perioperatively were included (2016-2019). Patients were stratified based on RBC transfusion volume: 1-2 units (39.3%), 3-4 units (29.4%), 5-6 units (15.9%) and ≥7 units (15.4%). Subgroup analyses were performed after stratification by case mix index, a standardized surrogate for patients' disease severity and comorbidities. Multivariable regression was used to assess risk factors for the development of postoperative VTE events. RESULTS: The overall VTE event rate was 2.4% (n = 19). A dose-response relationship was seen between RBC transfusion volume and VTE events (1-2 units: 0.97%, 3-4 units: 1.30%, 5-6 units: 3.20%, ≥7 units: 7.44%; p < 0.01). Similar dose-response relationships were seen between case mix index and VTE events (1.00-3.99: 0.52%, 4.00-6.99: 2.68%, ≥7.00: 9.00%; p < 0.01). On multivariable regression, larger RBC transfusion volumes (adjusted odds ratio [OR] 1.18 per RBC unit, 95% confidence interval [CI] 1.07-1.29; p < 0.01) and higher case mix index scores (adjusted OR 1.39 per unit increase, 95% CI 1.14-1.69; p < 0.01) were associated with an increased risk of thrombosis. CONCLUSION: Larger RBC transfusion volumes and higher case mix index scores were associated with an increased risk of VTE events. Physicians should be aware of how these dose-response relationships can influence a patient's risk of developing thrombotic complications postoperatively.

Acetate, a Short-Chain Fatty Acid, Acutely Lowers Heart Rate and Cardiac Contractility Along with Blood Pressure.

Short-chain fatty acids (SCFAs) are metabolites produced almost exclusively by the gut microbiota and are an essential mechanism by which gut microbes influence host physiology. Given that SCFAs induce vasodilation, we hypothesized that they might have additional cardiovascular effects. In this study, novel mechanisms of SCFA action were uncovered by examining the acute effects of SCFAs on cardiovascular physiology in vivo and ex vivo. Acute delivery of SCFAs in conscious radiotelemetry-implanted mice results in a simultaneous decrease in both mean arterial pressure and heart rate (HR). Inhibition of sympathetic tone by the selective ß-1 adrenergic receptor antagonist atenolol blocks the acute drop in HR seen with acetate administration, yet the decrease in mean arterial pressure persists. Treatment with tyramine, an indirect sympathomimetic, also blocks the acetate-induced acute drop in HR. Langendorff preparations show that acetate lowers HR only after long-term exposure and at a smaller magnitude than seen in vivo. Pressure-volume loops after acetate injection show a decrease in load-independent measures of cardiac contractility. Isolated trabecular muscle preparations also show a reduction in force generation upon SCFA treatment, though only at supraphysiological concentrations. These experiments demonstrate a direct cardiac component of the SCFA cardiovascular response. These data show that acetate affects blood pressure and cardiac function through parallel mechanisms and establish a role for SCFAs in modulating sympathetic tone and cardiac contractility, further advancing our understanding of the role of SCFAs in blood pressure regulation. SIGNIFICANCE STATEMENT: Acetate, a short-chain fatty acid, acutely lowers heart rate (HR) as well as mean arterial pressure in vivo in radiotelemetry-implanted mice. Acetate is acting in a sympatholytic manner on HR and exerts negative inotropic effects in vivo. This work has implications for potential short-chain fatty acid therapeutics as well as gut dysbiosis-related disease states.

Balancing the Blood Component Transfusion Ratio for High- and Ultra High-Dose Cell Salvage Cases.

OBJECTIVE: To assess the ratio of non-red blood cell to red blood cell components required to avoid coagulopathy when transfusing large amounts of salvaged blood using laboratory test-guided therapy. DESIGN: Retrospective cohort study. SETTING: Single-center, academic hospital. PARTICIPANTS: Thoracoabdominal and abdominal open aortic surgery patients. MEASUREMENT AND MAIN RESULTS: Thirty-eight patients in whom at least 1,000 mL of salvaged red blood cells were transfused were identified and divided into the following 2 cohorts: 1,000-to-2,000 mL of salvaged red blood cells (high dose) (n = 20) and >2,000 mL of salvaged red blood cells (ultra-high dose) (n = 18). Compared with the high-dose cohort, the ultra high-dose cohort received ∼4 times more salvaged red blood cells (1,240 ± 279 mL v 5,550 ± 3,801 mL). With transfusion therapy guided by intraoperative coagulation tests and thromboelastography, the adjusted ratio of non-red blood cell to red blood cell components (plasma + platelets + cryoprecipitate:allogeneic + salvaged red blood cells) was 0.59 ± 0.66 in the high-dose and 0.93 ± 0.27 in the ultra high-dose cohorts. Multiple coagulation parameters were normal and similar between cohorts at the end of surgery, as determined by the mean, median, and 95% confidence intervals. CONCLUSIONS: When transfusing large volumes of salvaged blood, it is important to balance the ratio between non-red blood cell and red blood cell components. Through a laboratory test-guided approach, coagulopathy was not detected when transfusing blood in ratios of approximately 1:2 for patients receiving 1,000-to-2,000 mL of salvaged blood and 1:1 for patients receiving >2,000 mL of salvaged blood.

How do I audit intraoperative blood component utilization in cardiac surgery?

BACKGROUND: Patient blood management programs are tasked with auditing transfusions for appropriateness; however, cardiac surgical programs have high variability in blood utilization. After benchmarking intraoperative blood utilization as higher than expected, we devised effective methods for audits with feedback to the cardiac anesthesiologists that are described in this report. STUDY DESIGN AND METHODS: Red blood cell (RBC), plasma, platelet (PLT), and cryoprecipitate transfusion data were collected from the electronic record system for 2242 patients having cardiac surgery from July 2016 until July 2018. In July 2017, we performed audits with feedback using rank-order bar graphs displayed on the anesthesiology office door for intraoperative blood utilization. Individual providers were compared to their peers for all four major blood components, with the goal of improving practice by reducing variability. RESULTS: After the audits with feedback, the intraoperative mean units/patient decreased for RBCs (from 1.9 to 1.2 units/patient; p = 0.0004), for plasma (from 1.8 to 1.2 units/patient; p = 0.0038), and for PLTs (from 0.7 to 0.4 units/patient; p < 0.0001), but not for cryoprecipitate (from 0.24 to 0.18 units/patient; p = 0.13). Whole hospital (from admit to discharge) utilization decreased significantly for plasma and PLTs, but the changes for RBCs and cryoprecipitate were nonsignificant. CONCLUSION: Despite challenges in abstracting data from the electronic medical record, using such data to create provider-specific audits with feedback can be an effective tool to promote quality improvement. Future plans include audits with feedback for providers who order transfusion outside the operating room.

Perioperative Care of the Obese Cardiac Surgical Patient.

Morbid obesity is associated with impairment of cardiovascular, pulmonary, gastrointestinal, and renal physiology with significant perioperative consequences and has been linked with higher morbidity and mortality after cardiac surgery. Cardiac surgery patients have a higher incidence of difficult airway and difficult laryngoscopy than general surgery patients do, and obesity is associated with difficult mask ventilation and direct laryngoscopy. Positioning injuries occur more frequently because obese patients are at greater risk of pressure injury, such as rhabdomyolysis and compartment syndrome. Despite the association between obesity and several chronic disease states, the effects of obesity on perioperative outcomes are conflicting. Studies examining outcomes of overweight and obese patients in cardiac surgery have reported varying results. An "obesity paradox" has been described, in which the mortality for overweight and obese patients is lower compared with patients of normal weight. This review describes the physiologic abnormalities and clinical implications of obesity in cardiac surgery and summarizes recommendations for anesthesiologists to optimize perioperative care of the obese cardiac surgical patient.

Continuous Intraoperative Cefazolin Infusion May Reduce Surgical Site Infections During Cardiac Surgical Procedures: A Propensity-Matched Analysis.

OBJECTIVES: The authors sought to determine whether an institutional transition from intermittent to continuous dosing of intraoperative antibiotics in cardiac surgery affected surgical site infection (SSI) outcomes. DESIGN: A retrospective chart review utilizing propensity matching. SETTING: A single academic, tertiary care hospital. PARTICIPANTS: One thousand one hundred seventy-nine patients undergoing coronary artery bypass grafting (CABG) and/or cardiac valvular surgery between April 2013 and November 2014 who received perioperative cefazolin. INTERVENTIONS: By method of cefazolin administration, patients were divided into an "intermittent-dosing" (ID) group and a "continuous-infusion" (CI) group. MEASUREMENTS AND MAIN RESULTS: Of the 1,179 patients who underwent cardiac surgery during the study period, 1:1 propensity score matching yielded 399 patients in each group. Rates of diabetes (33.6% ID v 33.8% CI, p = 0.94), coronary artery bypass (62.3% v 61.4%, p = 0.66), and bilateral internal mammary artery harvesting (6.0% v 8.3%, p = 0.22) were similar between groups. SSIs occurred in more ID patients than CI patients (2.3% v 0.5%, p = 0.03). This difference was driven by decreases in extremity and conduit harvest site SSIs (1.8% v 0.3%, p = 0.03), as there were no episodes of mediastinitis, and superficial sternal SSI rates did not differ (0.5% v 0.3%, p = 0.56). There also were significantly fewer episodes of pneumonia in the CI group (6.0% v 2.3%, p = 0.008). Intensive care unit and total lengths of stay did not differ. Thirty-day mortality was 2.8% in both groups (p = 1.00). CONCLUSIONS: As compared to ID regimens, CI cefazolin infusion may reduce post-cardiac surgery infectious complications. Further study in larger patient populations is needed.

ACE2 and TAS2R38 receptor expression in pediatric and adult patients in the nasal and oral cavity.

Objective: To investigate differences in angiotensin-converting-enzyme-2 (ACE2) and bitter taste receptor (TAS2R38) expression between patient age groups and comorbidities to characterize the pathophysiology of coronavirus 19(COVID-19) pandemic. ACE2 is the receptor implicated to facilitate SARS-CoV-2 infections and levels of expression may correlate to the severity of COVID-19 infection. TAS2R38 has many non-gustatory roles in disease, with some evidence of severe COVID-19 disease in certain receptor phenotypes. Methods: We conducted a prospective cohort study and collected nasal and lingual tissue from healthy pediatric (n = 22) and adult (n = 25) patients undergoing general anesthesia for elective procedures. RNA isolation and qPCR were performed with primers targeting ACE2 and TAS2R38. Results: A total of 25 adult (52% male; 44% obese) and 22 pediatric (50% male; 36% obese) patients were enrolled, pediatric tissue had 43% more nasal ACE2 RNA expression than adults with a median fold change of 0.69 (IQR 0.37, 0.98) in adults and 0.99 (IQR 0.74, 1.43) in children (p < .05). There were no differences between the age groups in ACE2 expression of lingual tissue (p = .14) or TAS2R38 expression collected from either nasal (p = 049) or lingual tissue (p = .49). Stratifying for obesity yielded similar differences between nasal ACE2 expression between adults and children with median fold change of 0.56 (IQR 0.32, 0.87) in adults and 1.0 (IQR 0.82, 1.52) in children (p < .05). Conclusions: ACE2 receptor expression is higher in nasal tissue collected from children compared to adults, suggesting COVID-19 infectivity is more complicated than ACE2 and TAS2R38 mRNA expression. Level of Evidence: NA.

Anesthetic Management for Open Thoracoabdominal and Abdominal Aortic Aneurysm Repair.

Open thoracoabdominal and abdominal aortic aneurysm repairs are some of the most challenging cases for anesthesiologists because of the potential for rapid blood loss combined with clamping and reperfusion, potential use of left heart bypass, the potential need for lung isolation, and potential placement and management of a spinal drain. In addition, patients often present with other significant comorbidities and a detailed understanding of the disease process, the complex physiology throughout the case, and the intricacies of organ protection are critical.

Assessment of left ventricle myocardial deformation in a hemorrhagic shock swine model by two-dimensional speckle tracking echocardiography.

BACKGROUND: Trauma-induced secondary cardiac injury has been associated with significant adverse cardiovascular events. Speckle tracking echocardiography is a novel technology that allows an accurate and reproducible cardiac structure and function assessment. We evaluated the left ventricle (LV) myocardial deformation by speckle tracking echocardiography in a hemorrhagic shock (HS) swine model. METHODS: Seven healthy male Landrace pigs were included in this study. Severe HS was reached through three sequentially blood withdraws of 20% of estimated blood volume, and it was maintained for 60 minutes. Volume resuscitation was performed using all precollected blood volume. A 1.8- to 4.2-MHz phased-array transducer was used to acquire the two-dimensional echocardiography images. Strain measurements were obtained semiautomatically by wall motion tracking software. Results are presented as medians and interquartile ranges and compared using Wilcoxon rank-sum test. A p value of <0.05 was considered statistically significant. RESULTS: The median weight was 32 (26.1-33) kg, and the median total blood volume withdrawn was 1,100 (1,080-1,190) mL. During the severe HS period, the median arterial systemic pressure was 39 (36-46) mm Hg, and the cardiac index was 1.7 (1.6-2.0) L/min/m 2 . There was statistically significant absolute decrease in the global longitudinal strain 2 hours postresuscitation comparing with the basal measurements (-9.6% [-10.7 to -8.0%] vs. -7.9% [-8.1 to -7.4%], p = 0.03). There were no statistically significant differences between the basal and 2 hours postresuscitation assessments in the invasive/noninvasive hemodynamic, other two-dimensional echocardiogram (LV ejection fraction, 49.2% [44-54.3%] vs. 53.2% [51.5-55%]; p = 0.09), and circumferential strain (-10.6% [-14.4 to -9.0%] vs. -8.5% [-8.6 to -5.2%], p = 0.06) parameters. CONCLUSION: In this experimental swine model of controlled HS, LV global longitudinal strain analysis accurately characterizes the timing and magnitude of subclinical cardiac dysfunction associated with trauma-induced secondary cardiac injury.

Selected Transesophageal Echocardiographic Parameters of Left Ventricular Diastolic Function Predict Length of Stay Following Coronary Artery Bypass Graft-A Prospective Observational Study.

(1) Importance: Abnormal left ventricular (LV) diastolic function, with or without a diagnosis of heart failure, is a common finding that can be easily diagnosed by intra-operative transesophageal echocardiography (TEE). The association of diastolic function with duration of hospital stay after coronary artery bypass (CAB) is unknown. (2) Objective: To determine if selected TEE parameters of diastolic dysfunction are associated with length of hospital stay after coronary artery bypass surgery (CAB). (3) Design: Prospective observational study. (4) Setting: A single tertiary academic medical center. (5) Participants: Patients with normal systolic function undergoing isolated CAB from September 2017 through June 2018. (6) Exposures: LV function during diastole, as assessed by intra-operative TEE prior to coronary revascularization. (7) Main Outcomes and Measures: The primary outcome was duration of postoperative hospital stay. Secondary intermediate outcomes included common postoperative cardiac, respiratory, and renal complications. (8) Results: The study included 176 participants (mean age 65.2 ± 9.2 years, 73% male); 105 (60.2%) had LV diastolic dysfunction based on selected TEE parameters. Median time to hospital discharge was significantly longer for subjects with selected parameters of diastolic dysfunction (9.1/IQR 6.6−13.5 days) than those with normal LV diastolic function (6.5/IAR 5.3−9.7 days) (p < 0.001). The probability of hospital discharge was 34% lower (HR 0.66/95% CI 0.47−0.93) for subjects with diastolic dysfunction based on selected TEE parameters, independent of potential confounders, including a baseline diagnosis of heart failure. There was a dose−response relation between severity of diastolic dysfunction and probability of discharge. LV diastolic dysfunction based on those selected TEE parameters was also associated with postoperative cardio-respiratory complications; however, these complications did not fully account for the relation between LV diastolic dysfunction and prolonged length of hospital stay. (9) Conclusions and Relevance: In patients with normal systolic function undergoing CAB, diastolic dysfunction based on selected TEE parameters is associated with prolonged duration of postoperative hospital stay. This association cannot be explained by baseline comorbidities or common post-operative complications. The diagnosis of diastolic dysfunction can be made by TEE.

Factors Associated With Pediatric Emergency Airway Management by the Difficult Airway Response Team.

Background The goal of this study was to determine if difficult airway risk factors were similar in children cared for by the difficult airway response team (DART) and those cared for by the rapid response team (RRT). Methods In this retrospective database analysis of prospectively collected data, we analyzed patient demographics, comorbidities, history of difficult intubation, and intubation event details, including time and place of the emergency and devices used to successfully secure the airway. Results Within the 110-patient cohort, median age (IQR) was higher among DART patients than among RRT patients [8.5 years (0.9-14.6) versus 0.3 years (0.04-3.6); P < 0.001]. The odds of DART management were higher for children ages 1-2 years (aOR, 43.3; 95% CI: 2.73-684.3) and >5 years (aOR, 13.1; 95% CI: 1.85-93.4) than for those less than one-year-old. DART patients were more likely to have craniofacial abnormalities (aOR, 51.6; 95% CI: 2.50-1065.1), airway swelling (aOR, 240.1; 95% CI: 13.6-4237.2), or trauma (all DART managed). Among patients intubated by the DART, children with a history of difficult airway were more likely to have musculoskeletal (P = 0.04) and craniofacial abnormalities (P < 0.001), whereas children without a known history of difficult airway were more likely to have airway swelling (P = 0.04). Conclusion Specific clinical risk factors predict the need for emergency airway management by the DART in the pediatric hospital setting. The coordinated use of a DART to respond to difficult airway emergencies may limit attempts at endotracheal tube placement and mitigate morbidity.

Low-dose ketamine for analgesia in the ED: a retrospective case series.

OBJECTIVES: The aim of this study was to describe the use and effect of low-dose ketamine (LDK) for analgesia in the emergency department (ED). METHODS: A chart review was performed to identify all adult patients who received LDK for analgesia in our ED. Cases were identified by pharmacy record of ketamine administration. Low-dose ketamine was defined as the administration of 0.1 to 0.6 mg/kg of ketamine for pain control. Use of ketamine during procedural sedation was excluded. Data were analyzed descriptively. RESULTS: Thirty-five cases in which patients received LDK in the ED for a 2-year period were identified. Doses ranged from 5 to 35 mg. Administration was intravenous in 30 (86%) of 35 cases and intramuscular in 5 (14%) of 35 cases. Opioids were administered before or coadministered with LDK in 32 (91%) of 35 cases, and in the remaining 3 cases, opioids were used before the patient came to the ED. Improvement in pain was observed in 19 (54%) of 35 cases in which patients received LDK. Pain scores did not improve in 8 (23%) of 35 cases. Insufficient data were available to determine LDK effect for 8 (23%) of 35 cases. No significant adverse events were identified in any of the 35 cases. CONCLUSIONS: The administration of LDK in the ED may be a safe and effective adjunct for analgesia in some patients. However, prospective randomized controlled trials are needed before widespread use of LDK for analgesia in the ED can be recommended.

Using the SuperNO2VA Device on a Patient With a Known Difficult Airway: A Case Report Facilitating Fiberoptic Intubation and Postoperative Nasal Positive Pressure.

Upper airway obstruction during anesthesia is the leading cause of complications during sedation, intubation, and emergence. Devices to support oxygenation and ventilation are costly, require capital equipment, and cannot be used during transport. We present a 46-year-old man with sleep apnea and anticipated difficult airway undergoing a cardiac ablation under general endotracheal intubation. The SuperNO2VA nasal mask provided high-flow nasal oxygen and positive pressure during awake fiberoptic intubation and on extubation, maintaining airway patency in the operating room, during transport, and in recovery. The SuperNO2VA is inexpensive and portable and should be considered for high-risk patients with difficult airways.

A Decade of Difficult Airway Response Team: Lessons Learned from a Hospital-Wide Difficult Airway Response Team Program.

A decade ago the Difficult Airway Response Team (DART) program was created at The Johns Hopkins Hospital as a multidisciplinary effort to address airway-related adverse events in the nonoperative setting. Root cause analysis of prior events indicated that a major factor in adverse patient outcomes was lack of a systematic approach for responding to difficult airway patients in an emergency. The DART program encompasses operational, safety, and educational initiatives and has responded to approximately 1000 events since its initiation, with no resultant adult airway-related adverse events or morbidity. This article provides lessons learned and recommendations for initiating a DART program.