fference in the effectiveness of topical and intravenous application of lidocaine for the blunting of increased heart rate and blood pressure in patients undergoing laryngoscopy and intubation.
The nursing anesthesiest has the goal of assisting the patient to the greatest degree, without harm. This expertise will return the patient to a healthy state. To reach these goals, the use of any anestesia, including lidocaine, requires an understanding of the most appropriate administration route. The negative effects of laryngoscopy and tracheal intubation are recognized to include increased heart rate and blood pressure. Lidocaine offers a solution to these problems, and an understanding of the most effective method of administration will be of assistance to the nurse anesthetist.
Laryngoscopy and intubation interrupt an individual's reflex action. Protective airway reflexes are in place and when violated they lead to tachycardia and hypertension. These responses can be blunted with the use of intravenous and topical administration of lidocaine (1.5 mg/kg 1-2 minutes before laryngoscopy has been recommended) (Morgan & Mikhail, 1992).
Lidocaine causes vasodilatation due to direct smooth muscle relaxation. The sympathetic nervous system (SNS) involves a network of neurons and fibers located in the central and peripheral nervous systems. Stimulation of the SNS results in the release of catecholamines (epinephrine, norepinephrine, and dopamine). Epinephrine stimulates alpha and beta-adrenergic receptors. The stimulation of beta receptors results in increased heart rate and systolic blood pressure; the most important beta receptors are found on post-synaptic membranes in the heart. Norepinephrine stimulates vascular resistance with a decrease of venous return and it increases mean arterial pressure (systolic and diastolic) (Morgan & Mikhail, 1996).
The cardiac impulse originates in the sinoatrial (SA) node, which is a ...