Poiseuille’s law states the volume in a tube is directly proportional to pressure difference between both ends of the tube and inversely related to the length. Poiseuille’s law was discovered by Jean Louis Marie Poiseuille in 1840 (Poiseuille’s). Jean Louis used his experiments to find the smooth, laminar flow in circular tubing (Jean-Louis). His findings can be described as the flow of blood through the body and bronchial smooth muscle.
When the resistance of a fluid increases, the flow will decrease. One example of this is gravy and milk. Gravy has a greater resistance than milk and will take longer to flow out of a pitcher. The same can be said about respiratory therapy equipment. An increase in viscosity will decrease the flow. When Jean Poiseuille was creating his experiments, he used the circulation of blood through the body to explain his findings. Respiratory therapists must understand Poiseuille’s law of flow because blood vessels in the lungs vary both in size and pressure. As the vessels move farther away from the heart, they reduce in size and increase in surface area. Capillaries in the lungs are extremely small, but have a vast amount of surface area they can cover.
When a patient is exercising, blood vessels will become dilated and blood pressure will increase (Connexions). Patients who have a constantly high blood pressure will have a decrease in cardiac muscle tone and thin blood vessel walls. Capillaries tend to be extremely small, which causes them to have a decreased radius and an increase in airway resistance. Poiseuille’s law states that a decrease in half the radius will cause an increase of airway resistance by sixteen percent (Connexions).
Poiseuille’s law concerns mainly with laminar flow, but can extend to turbulent flow (Poiseuille’s). Laminar flow is classified as having a smooth parallel flow without mixture. Turbulent flow is classified as a twisted and mixed flow. Laminar flow can be described in the lungs and turbulent flow can be described in the vestibular region of the nasopharynx. Airway resistance can be determined by three things: length, diameter, and viscosity (Livemedical). Increasing in the length of the endotracheal tube will require additional pressure to be needed to get the adequate amount of oxygen into the lungs.
The bronchial tubes increase...