Carbon Dioxide Pyelography: A Convenient and Safe Alternative to Both Room Air and Iodinated Contrast Pyelography During Endourologic Procedures.

Introduction/Background: There are increasing reports of serious complications related to the air pyelography technique, which raise concerns about the safety of room air (RA) injection into the renal collecting system. Carbon dioxide (CO2) is much more soluble in blood than nitrogen and oxygen and thus considerably less likely to cause gas emboli. Iodinated contrast medium (ICM) is expensive, and supplies may not be as reliable as previously assumed. CO2 pyelography (CO2-P) techniques using standard fluoroscopy and digital subtraction fluoroscopy (CO2 digital subtraction pyelography [CO2-DSP]) are described. Materials and Methods: During the endourologic stone cases, 15 to 20 mL of CO2 gas was typically injected into the renal pelvis through a catheter or sheath. Imaging was usually obtained with endovascular CO2 digital subtraction angiography settings using either a traditional fluoroscopy system (TFS) or robotic arm multiplanar fluoroscopy system (RMPFS) (Artis Zeego Care+Clear®; Siemens). Results: CO2-P was performed in 22 endoscopic stone treatment cases between March 2021 and August 2022, primarily using digital subtraction settings in 20 cases. CO2-DSP overall provided higher quality images of the renal pelvis and collecting system than CO2-P, but with a relatively higher radiation dose. Following a quality intervention, fluoroscopy doses for CO2-DSP cases were decreased by 81% overall. The use of CO2-P avoided fluoroscopic or intraoperative CT (ICT) artifacts seen with intraluminal ICM. Conclusions: CO2-P allows the urologist to obtain imaging of the renal collecting system without ICM and with much lower risk of air embolism compared with RA pyelography. CO2 is a nearly cost-free alternative to ICM. Because CO2 is widely available and the technique is easy to perform, we propose that CO2-P should be favored over traditional air pyelography to improve patient safety.

Perioperative Clerkship Design for Students with Physical Disabilities: A Model for Implementation.

OBJECTIVE: Disability inclusion is an important and growing area of focus for medical education that may be stymied by stereotypes about disabilities, lack of knowledge about accommodations for students with physical disabilities, or outdated technical standards that preclude participation of people with mobility disabilities. To support the inclusion of students with physical disability in surgical clerkships, we describe a proactive, progressive approach to the accommodations process for a student with a thoracic spinal cord injury entering a surgical clerkship. DESIGN: Working proactively, medical school leadership, disability professionals and the clerkship team collaborated on the development of reasonable accommodations for a student with a thoracic spinal cord injury entering a surgical clerkship. SETTING: University of Colorado, Department of Surgery and Department of Medical Education, Aurora, CO. PARTICIPANTS: A third-year medical student and faculty from the medical school and surgical clerkship leaders. RESULTS: An M3 student with a thoracic spinal cord injury successfully completed an 8-week surgical clerkship completing all required procedural and clinical skills utilizing reasonable accommodation. The student achieved a grade of honors for the rotation. CONCLUSIONS: Early communication and planning for disability-related adjustments are critical to ensure an accessible experience for students with physical disabilities. The addition of a student with a disability adds to a better understanding of inclusive practices for surgical education and adds to the diversity of thought and experience for the medical education community.

Right Ventricular Longitudinal Strain In Left Ventricular Assist Device Surgery-A Retrospective Cohort Study.

OBJECTIVES: Right ventricular (RV) failure is common after left ventricular assist device (LVAD) surgery and is associated with higher mortality. Measurement of longitudinal RV strain using speckle-tracking technology is a novel approach to quantify RV function. The authors hypothesized that depressed peak longitudinal RV strain measured by intraoperative transesophageal echocardiography (TEE) examinations would be associated with adverse outcomes after LVAD surgery. DESIGN: Retrospective cohort study. SETTING: Tertiary academic medical center. PARTICIPANTS: Following Institutional Review Board approval, the authors retrospectively identified adult patients who underwent implantation of non-pulsatile LVAD. Exclusion criteria included inadequate TEE images and device explantation within 6 months for heart transplantation. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The postoperative adverse event outcome was defined as a composite of one or more of death within 6 months, ≥14 days of inotropes, mechanical RV support, or device thrombosis. Intraoperative TEE images were analyzed for peak RV free wall longitudinal strain by two blinded investigators. Simple logistic regression was used to assess the relationship between adverse outcome and the mean of the strain measurements of the two raters. Agreement between the raters was assessed by intra-class correlation (0.62) and Pearson correlation coefficient (0.63). Of the 57 subjects, 21 (37%) had an adverse outcome. The logistic regression indicated no significant association between RV peak longitudinal strain and adverse events. CONCLUSIONS: In this retrospective study of patients undergoing non-pulsatile LVAD implantation, peak longitudinal strain of the RV free wall was not associated with adverse outcomes within 6 months after surgery. Additional quantitative echocardiographic measures for intraoperative RV assessment should be explored.

Ultrasonography for haemodynamic monitoring.

Echocardiography has become an indispensable tool in the evaluation of medical and surgical patients. As ultrasound (US) machines have become more widely available and significantly more compact, there has been an exponential growth in the use of transthoracic echocardiography (TTE), transoesophageal echocardiography (TOE) and other devices in the perioperative setting. Here, we review recent findings relevant to the use of perioperative US, with a special focus on the haemodynamic management of the surgical patient.

Clonidine prolongation of lidocaine analgesia after sciatic nerve block in rats Is mediated via the hyperpolarization-activated cation current, not by alpha-adrenoreceptors.

BACKGROUND: Although clonidine is commonly combined with local anesthetics to extend duration of peripheral nerve block, the mechanism by which clonidine potentiates local anesthetic action in vivo is unclear. METHODS: Male Sprague-Dawley rats received percutaneous injections of 1% lidocaine with/without clonidine or epinephrine into the sciatic notch and duration of sensory blockade was quantified by inhibition of pinprick foot withdrawal. The antagonists prazosin or yohimbine were injected before lidocaine with clonidine or epinephrine to determine the role of alpha-adrenergic receptors. The role of the hyperpolarization-activated cation current (Ih) was evaluated by injecting the current blocker ZD 7288 as well as the current enhancers forskolin and 8-Br-cAMP before lidocaine alone or with 15 micrograms/ml clonidine. RESULTS: Mean duration of sensory block for lidocaine alone was 69 +/- 2 min. Sensory block duration increased monotonically with increasing doses of added clonidine or epinephrine. Preinjection of prazosin but not yohimbine prevented the increase in block duration seen with epinephrine. Neither alpha-adrenergic antagonist attenuated the extended duration of block with clonidine. ZD 7288 extended sensory blockade equivalent to the prolongation observed with clonidine. There was no additive effect when ZD 7288 and clonidine were combined, and a decreased duration of nerve block when either forskolin or 8-Br-cAMP preceded injection of lidocaine with clonidine. CONCLUSIONS: The findings indicate that prolongation of duration of in vivo lidocaine nerve blockade by clonidine is not mediated by an alpha-adrenergic mechanism but likely involves the Ih current.