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Introduction Invasive blood pressure monitoring is essential in liver transplant surgery due to expected major hemodynamic shifts. The use of central versus peripheral arterial access, however, is institution-dependent, which can affect clinical decisions regarding vasopressor therapy. Although there are studies that demonstrate inconsistencies based on arterial cannulation sites, few studies have compared femoral and radial artery blood pressures in patients undergoing liver transplant surgery. To our knowledge, there are no studies investigating the differences between continuous minute-to-minute femoral and radial artery measurements during all three phases of liver transplant surgery. Objective The main objective of this study was to evaluate for any differences between central and peripheral blood pressure measurements in liver transplant surgery and to assess for any correlation between vasopressor infusion dose and femoral-arterial pressure differences. Methods In this retrospective study, we reviewed and studied the data of 61 patients with American Society of Anesthesiologists (ASA) grade 4 who underwent liver transplant surgery at Loma Linda University Medical Center between January and December of 2019. All patients had both femoral and radial arterial lines placed for liver transplant surgery. Femoral and radial arterial blood pressure values were obtained continuously over 60 minutes in the pre-anhepatic phase, 45 minutes during the anhepatic phase, and 60 minutes into the neo-hepatic phase. Vasopressor infusion doses were also recorded for each patient during these time frames. Results This pilot study found statistically significant differences between the mean femoral and radial systolic blood pressure (SBP; p < 0.0001), diastolic blood pressure (DBP; p < 0.0001), and mean arterial pressure (MAP; p < 0.0001) during all phases of liver transplantation. The meanSBP and MAP differences between femoral and radial arteries were highest (femoral blood pressure reading higher than radial blood pressure measurements) in the late anhepatic and early neo-hepatic phases with SBP differences of 20.8 ± 0.8 mmHg and 22.8 ± 0.8 mmHg, respectively, and MAP differences of 10.0 ± 0.4 mmHg and 9.8 ± 0.4 mmHg, respectively. Higher vasopressor infusion doses were strongly associated with greater differences in femoral-radial SBP and MAP measurements (r = 0.69 for vasopressin, 0.68 for norepinephrine, and 0.68 for epinephrine; p < 0.0001) during the anhepatic phase. Conclusions Peripheral invasive blood pressure monitoring may result in underestimation of the central blood pressure, as was seen in all phases of liver transplantation. This may lead to excessive vasopressor use with potentially adverse effects. Although the cause for the difference between femoral and radial artery measurements is unclear, increasing vasopressor infusion dosages appears to contribute. Femoral artery blood pressure monitoring allows clinicians to interpret hemodynamic status and administer appropriate vasopressors more accurately.
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The Eustachian valve is an embryologic remnant at the junction of the inferior vena cava (IVC) and right atrium (RA). While it typically does not have any pathologic significance, veno-arterial shunting can rarely occur in patients with prominent eustachian valves and atrial septal defects (ASD), causing cyanosis and hypoxemia despite normal pulmonary pressures. We present a case of a patient with iatrogenic residual sinus venosus IVC-type ASD secondary to a prominent Eustachian valve that was misinterpreted as the inferior rim of the atrial septum during initial ASD repair.
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INTRODUCTION: Accuracy of fluoroscopy in predicting septal placement of the right ventricular (RV) leads is poor. This pilot study evaluated the feasibility and impact of real-time transthoracic echocardiogram (TTE) during RV lead placement. METHOD: Consecutive patients undergoing transvenous RV lead placement and had a point of care ultrasound team available for TTE guidance were included in the study. TTE was performed to confirm or refute the septal position of RV lead initially positioned using fluoroscopy; leads were repositioned until a septal position was confirmed on TTE. The primary outcome measured was whether the use of TTE resulted in lead repositioning. RESULT: Among the 26 patients included in the study, real-time TTE during RV lead placement resulted in reposition of the lead to a septal position in 38.5% of patients. CONCLUSION: Use of real-time TTE guidance during fluoroscopic RV lead placement is feasible and can aid in confirming a septal position.
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Anesthetic management for patients with certain neuromuscular disorders may be challenging due to contraindications to triggering agents secondary to increased susceptibility for malignant hyperthermia (MH). Inclusion body myositis (IBM) is an inflammatory muscle disease that causes concern for the anesthesiologist due to potential respiratory muscle weakness and hyperkalemia with succinylcholine. Elevated serum creatinine kinase levels found in IBM also raise the possibility of increased susceptibility to MH. This case report describes a successful anesthetic course with special considerations in a patient with IBM undergoing general anesthesia for coronary artery bypass grafting (CABG) under cardiopulmonary bypass (CPB) using total intravenous anesthesia (TIVA).
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This review aims to broadly describe drug infusion technologies and raise subtle but important issues arising from infusion therapy that can potentially lead to patient instability and morbidity. Advantages and disadvantages of gravity-dependent drug infusion are described and compared with electromechanical approaches for precise control of medication infusion, including large-volume peristaltic and syringe pumps. This review discusses how drugs and inert carriers interact within infusion systems and outlines several complexities and potential sources of drug error. Major topics are (1) the importance of the infusion system dead volume; (2) the quantities of coadministered fluid and the concept of microinfusion; and (3) future directions for drug infusion.The infusion system dead volume resides between the point where drug and inert carrier streams meet and the patient's blood. The dead volume is an often forgotten reservoir of drugs, especially when infusion flows slow or stop. Even with medications and carriers flowing, some mass of drug always resides within the dead volume. This reservoir of drug can be accidentally delivered into patients. When dose rate is changed, there can be a significant lag between intended and actual drug delivery. When a drug infusion is discontinued, drug delivery continues until the dead volume is fully cleared of residual drug by the carrier. When multiple drug infusions flow together, a change in any drug flow rate transiently affects the rate of delivery of all the others. For all of these reasons, the use of drug infusion systems with smaller dead volumes may be advantageous.For critically ill patients requiring multiple infusions, the obligate amount of administered fluid can contribute to volume overload. Recognition of the risk of overload has given rise to microinfusion strategies wherein drug solutions are highly concentrated and infused at low rates. However, potential risks associated with the dead volume may be magnified with microinfusion. All of these potential sources for adverse events relating to the infusion system dead volume illustrate the need for continuing education of clinical personnel in the complexities of drug delivery by infusion.This review concludes with an outline of future technologies for managing drug delivery by continuous infusion. Automated systems based on physiologic signals and smart systems based on physical principles and an understanding of dead volume may mitigate against adverse patient events and clinical errors in the complex process of drug delivery by infusion.
