Identify the law of Anesthesia shown in the image.
A. Boyle’s Law
B. Charle’s Law
C. Graham’s Law
D. Poiseuille Law
Ans:D. Poiseuille Law
- It states that the flow of liquid depends on following factors like the pressure gradient (∆P), the length of the narrow tube (L) of radius (r) and the viscosity of the fluid (η) along with relationship among them.
- It is useful in determining the flow rate of intravenous fluids that may be achieved using various sizes of peripheral and central cannulas.
- The entire relation or the Poiseuille’s Law formula is given by,
- Q = ΔPπr4 / 8ηl
- The Pressure Gradient (∆P) : Shows the difference in the pressure between the two ends of the tube, determined by the fact any fluid will always flow from high pressure (p1) to low pressure region(p2) and the flow rate is determined by the pressure gradient (P1 – P2)
- Radius of tube: The liquid flow varies directly with the radius to the power 4.
- Viscosity (η): The flow of the fluid varies inversely with the viscosity of the fluid and as the viscosity of the fluid increases, the flow decreases vice versa.
- Length of the Tube (L): The liquid flow is inversely proportional to the length of the tube, therefore longer the tube, greater is the resistance to the flow.