Carbon Footprint of Total Intravenous and Inhalation Anesthesia in the Transcatheter Aortic Valve Replacement Procedure.

OBJECTIVES: To quantify and compare the emissions for deep sedation with total intravenous anesthesia (TIVA) and general anesthesia with inhaled agents during the transcatheter aortic valve replacement procedure. DESIGN: A retrospective study. SETTING: A tertiary hospital in Boston, Massachusetts. PARTICIPANTS: The anesthesia records of 604 consecutive patients who underwent the transcatheter aortic valve replacement procedure between January 1, 2018, and March 31, 2022, were reviewed and analyzed. INTERVENTIONS: Data were examined and compared in the following 2 groups: general anesthesia with inhaled agents and deep sedation with TIVA. MEASUREMENTS AND MAIN RESULTS: The gases, drugs, airway management devices, and anesthesia machine electricity were collected and converted into carbon dioxide emissions (CO2e). The carbon emissions of intravenous medications were converted with the CO2e data for anesthetic pharmaceuticals from the Parvatker et al. study. For inhaled agents, inhaled anesthetics and oxygen/air flow rate were collected at 15-minute intervals and calculated using the anesthetic gases calculator provided by the Association of Anesthetists. The airway management devices were converted based on life-cycle assessments. The electricity consumed by the anesthesia machine during general anesthesia was estimated from the manufacturer's data (Dräger, GE) and local Energy Information Administration data. The data were analyzed in the chi-squared test or Wilcoxon rank-sum test. There were no significant differences in the patients' demographic characteristics, such as age, sex, weight, height, and body mass index. The patients who received general anesthesia with inhaled agents had statistically higher total CO2e per case than deep sedation with TIVA (16.188 v 1.518 kg CO2e; p < 0.001), primarily due to the inhaled agents and secondarily to airway management devices. For deep sedation with TIVA, the major contributors were intravenous medications (71.02%) and airway management devices (16.58%). A subgroup study of patients who received sevoflurane only showed the same trend with less variation. CONCLUSIONS: The patients who received volatile anesthesia were found to have a higher CO2e per case. This difference remained after a subgroup analysis evaluating those patients only receiving sevoflurane and after accounting for the differences in the duration of anesthesia. Data from this study and others should be collectively considered as the healthcare profession aims to provide the best care possible for their patients while limiting the harm caused to the environment.

Midsagittal tissue bridges are associated with walking ability in incomplete spinal cord injury: A magnetic resonance imaging case series.

Context: Following spinal cord injury (SCI), early prediction of future walking ability is difficult, due to factors such as spinal shock, sedation, impending surgery, and secondary long bone fracture. Accurate, objective biomarkers used in the acute stage of SCI would inform individualized patient management and enhance both patient/family expectations and treatment outcomes. Using magnetic resonance imaging (MRI) and specifically a midsagittal T2-weighted image, the amount of tissue bridging (measured as spared spinal cord tissue) shows potential to serve as such a biomarker. Ten participants with incomplete SCI received MRI of the spinal cord. Using the midsagittal T2-weighted image, anterior and posterior tissue bridges were calculated as the distance from cerebrospinal fluid to the damage. Then, the midsagittal tissue bridge ratio was calculated as the sum of anterior and posterior tissue bridges divided by the spinal cord diameter. Each participant also performed a 6-minute walk test, where the total distance walked was measured within six minutes.Findings: The midsagittal tissue bridge ratio measure demonstrated a high level of inter-rater reliability (ICC = 0.90). Midsagittal tissue bridge ratios were significantly related to distance walked in six minutes (R = 0.68, P = 0.03).Conclusion/clinical relevance: We uniquely demonstrated that midsagittal tissue bridge ratios were correlated walking ability. These preliminary findings suggest potential for this measure to be considered a prognostic biomarker of residual walking ability following SCI.

Establishing the inter-rater reliability of spinal cord damage manual measurement using magnetic resonance imaging.

Study design: Retrospective study. Objectives: To establish the inter-rater reliability in the quantitative evaluation of spinal cord damage following cervical incomplete spinal cord injury (SCI) utilizing magnetic resonance imaging (MRI). MRI was used to perform manual measurements of the cranial and caudal boundaries of edema, edema length, midsagittal tissue bridge ratio, axial damage ratio, and edema volume in 10 participants with cervical incomplete SCI. Setting: Academic university setting. Methods: Structural MRIs of 10 participants with SCI were collected from Northwestern University's Neuromuscular Imaging and Research Lab. All manual measures were performed using OsiriX (Pixmeo Sarl, Geneva, Switzerland). Intraclass correlation coefficients (ICC) were used to determine inter-rater reliability across seven raters of varying experience. Results: High-to-excellent inter-rater reliability was found for all measures. ICC values for cranial/caudal levels of involvement, edema length, midsagittal tissue bridge ratio, axial damage ratio, and edema volume were 0.99, 0.98, 0.90, 0.84, and 0.93, respectively. Conclusions: Manual MRI measures of spinal cord damage are reliable between raters. Researchers and clinicians may confidently utilize manual MRI measures to quantify cord damage. Future research to predict functional recovery following SCI and better inform clinical management is warranted.