Lasers in Medicine: Healing with Light
Suzanne Amador Kane, Boris A. Gelman in Introduction to Physics in Modern Medicine, 2020
Figure 3.24 shows absorption spectra characteristic of the blood's oxygen-carrying protein, hemoglobin. Hemoglobin has a chemical group, called a heme, a complex of iron and other atoms with loosely bound electrons, which absorbs visible light. This heme group is responsible both for the molecule's color and for its ability to bind oxygen. The heme group has different absorption spectra depending on whether or not it is bound to oxygen. When bound to oxygen (oxyhemoglobin), hemoglobin appears red because short wavelengths are heavily absorbed – the blues less strongly than the greens and yellows – and longer, red ones are hardly at all. (You can see this from Figure 3.24, which has low extinction coefficient values for wavelengths over 600 nm [the red], larger values throughout the yellow and green [590 to 520 nm], and intermediate values for less than 520 nm [the blue-green and blue].) Hemoglobin not bound to oxygen (deoxyhemoglobin) absorbs light with wavelengths in the blue range less strongly than when it is oxygenated (Figure 3.24). Hence appreciable amounts of both red and blue light get transmitted. This is why oxygen-rich arterial blood is deep red and oxygen-poor venous blood has a purplish tint.
Extracorporeal life support for neonatal cardiorespiratory failure
Prem Puri in Newborn Surgery, 2017
Venoarterial (VA) ECMO involves drainage of venous blood from the infant (typically from the right atrium, through a cannula placed in the right internal jugular vein) and return of oxygenated blood into the aorta (typically through a cannula placed in the right common carotid artery). This mode augments or replaces the function of both the heart and lungs. For infants with respiratory failure but preserved hemodynamics, venovenous (VV) ECMO support may be appropriate. VV ECMO is most often delivered through a dual lumen cannula directed into the right atrium through the right internal jugular vein. Venous blood is drained from the atrium to the circuit, and the oxygenated blood is returned to the atrium, with flow directed toward the tricuspid valve in an attempt to avoid mixing and recirculation through the circuit. Though cannula design is intended to minimize recirculation, cardiac output is the greatest determinant, and poor cardiac function will cause the recirculation of oxygenated blood through the ECMO circuit, diminishing the delivery of oxygenated blood to the patient. Bicaval dual lumen cannulas are used extensively in adults and older children. These cannulas are positioned across the right atrium into the inferior vena cava, and blood is drained from the superior vena cava (SVC) and the inferior vena cava (IVC) and returned to the atrium, reducing recirculation. In infants, however, the rate of atrial perforation related to bicaval cannula use is considered by some practitioners to be unacceptably high,17 and so dual lumen atrial, rather than bicaval, cannulas are preferred (Figure 44.1).
Venous and Arterial Access, EP Catheters, Positioning of Catheters
Andrea Natale, Oussama M. Wazni, Kalyanam Shivkumar, Francis E. Marchlinski in Handbook of Cardiac Electrophysiology, 2020
The internal jugular vein is located anterior and lateral to the carotid artery. It lies behind the clavicular head of the sternocleidomastoid muscle. The site of puncture is approximately at the level of the apex formed by both heads of the sterno-cleidomastoid muscle and medial to the lateral border of the clavicular head. The Trendelenberg position is helpful in distending the vein. The syringe and needle are directed lateral to the carotid artery. When a free flow of venous blood is encountered, the syringe is detached, the needle held firmly, and a guide-wire advanced. At all times the guide-wire should be advanced without any perceived resistance. The needle is then removed and an intravascular sheath advanced as described previously. The potential complications of internal jugular vein access include carotid artery puncture with resultant hematoma, potential air embolism, and pneumothorax. Digital pressure should be maintained for 5–10 min in the event of inadvertent carotid artery puncture. Air embolism can be prevented by keeping the patient in the Trendelenberg position until the sheath is advanced. The risk of pneumothorax can be minimized by obtaining access in the neck at a higher level.
A genetic variation in CHI3L1 is associated with bronchial asthma
Published in Archives of Physiology and Biochemistry, 2021
Jinlian Shao, Xuexi Yang, Dunqiang Ren, Yaling Luo, Wenyan Lai
Peripheral venous blood was collected from all subjects. DNA was extracted with kits (TIANamp Genomic DNA Kit, TianGen, Beijing, China). A previous genome-wide association study showed tight linkage disequilibrium in CHI3L1 in Asian populations (Rathcke et al. 2009). Ober et al. (2008) found that CHI3L1 is a susceptibility gene for asthma, bronchial hyperresponsiveness and reduced lung function; four SNPs (rs2153101, rs4950928, rs4950929 and rs946263) showed the strongest association with serum YKL-40 levels and asthma in the Hutterites. However, to our knowledge, no study has reported the genetic variation in CHI3L1 in Chinese asthmatic patients. Based on previous studies, we analyzed four CHI3L1 SNPs (rs2153101, rs4950928, rs4950929 and rs946263) in our patients. All SNPs were genotyped using the SEQUENOM MassARRAY matrix-assisted laser desorption ionization-time of flight mass spectrometry platform (Sequenom, San Diego, CA, USA).
Management of asymptomatic severe hypertriglyceridemia
Published in Baylor University Medical Center Proceedings, 2022
Nathalie V. Scherer, Dipesh Bista
A recently pregnant 33-year-old woman with known mild hyperlipidemia presented to an emergency department with fatigue, polyuria, polydipsia, and new onset yellow-pigmented papules on her chest and back. Initial workup showed blood glucose >1000 mg/dL, total cholesterol >900 mg/dL, TG 2788 mg/dL, high-density lipoprotein cholesterol 78 mg/dL, and low-density lipoprotein cholesterol 483 mg/dL. The patient was admitted for a hyperglycemic hyperosmolar state and started on an intravenous insulin drip along with intravenous hydration. Overnight, as her blood glucose was controlled, the intravenous insulin drip was stopped and transitioned to subcutaneous insulin. The next morning, however, her blood TG level was significantly elevated at 13,800 mg/dL. She was restarted on an intravenous insulin drip for acute management of severe hypertriglyceridemia. Repeat laboratory tests showed that blood TG had further increased to 20,100 mg/dL. A venous blood sample was notably milky and light pink. The patient did not show any evidence of acute pancreatitis but did have an elevated lactic acid level, which was concerning for impending end-organ dysfunction due to blood hyperviscosity.3 Despite being on an insulin drip, fenofibrate, and omega-3 fatty acid, she had persistent, severe hypertriglyceridemia.
Propulsion of blood through the right heart circulatory system
Published in Scandinavian Cardiovascular Journal, 2018
Torvind Næsheim, Ole-Jakob How, Truls Myrmel
An important but less focused model of venous return, was proposed by the Danish physiologist and Nobel laureate Schack August Steenberg Krogh (1874–1949) in 1912 [9]. Krogh clarified the capillary circulation, and the Krogh-model demonstrates how blood can flow through the various venous compartment depending on local heterogeneous resistances oriented in parallel systems (Figure 2). Local metabolism, neurohormonal reflexes and probably paracrine factors can alter local flow fractions and also the time constant [3] of venous blood flow in various compartments. This is in the figure illustrated in a two-compartment model of venous return with the splanchnic and peripheral muscle compartments as model systems. The model can, however, be expanded to include all venous compartments. Mathematically, venous return (VR) can be expressed as; 3]. The time spent in “storage” will of course greatly determine the functional return of venous blood in the body.