الفهرس 
ANATOMY AND PHYSIOLOGY OFOnly 14 pages are availabe for public view
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Abstract
Pressor effects of laryngoscopy and tracheal intubation (TI) are due to reflex sympatho-adrenal discharge provoked by epilaryngeal and laryngotracheal stimulation subsequent to laryngoscopy and TI, which results in hypertension, tachycardia, arrhythmia and a change in plasma catecholamine concentrations leading to a decrease in the left ventricular ejection fraction (stroke volume/end-diastolic volume) and ST-segment changes that indicate myocardial ischemia. These responses can be problematic to patients suffering from cardio-vascular, cerebro-vascular or abdomino-vascular disease in which hypertension can lead to hemorrhage.
Sympathetic stimulation from TI also increases the ICP which can be harmful in patients with intracranial mass lesions or increased ICP from other pathology, and increases IOP which is dangerous in patients with impending perforation of eye, perforating eye injuries and. glaucoma. Control of IOP during ophthalmic surgery is also clinically important, because airway manipulation may worsen ocular morbidity.
Many attempts have been made to attenuate the pressor effects of laryngoscopy and TI including drugs as: General anesthetics (IV thiopentone, propofol and nitrous oxide), intravenous lidocaine, opioids, selective β- adrenoceptor blockers, calcium channel blockers, α-2 adrenoceptor agonists (clonidine and dexmedetomidine) and other drugs such as magnesium sulphate, gabapentin and pregabalin.
This pressor response can be decreased non pharmacologically as a supplementary or complementary methods to the pharmacological agents, thus improving morbidity and mortality while decreasing or avoiding the side effects of these agents.
McCoy laryngoscope (as one of the non pharmacological methods) shows a greater benefit over the Macintosh laryngoscope as it results in less force being applied on the tissues of the upper airway during laryngoscopy and thus stress response is reduced.
Fiberoptic bronchoscope, video assisted devices and Lightwand intubation may not require a laryngoscope to elevate the epiglottis, has shown faster times to intubation, fewer intubation attempts and less trauma than direct laryngoscopy, and significantly attenuates the pressor response to TI in hypertensive patients and also during awake TI.
The LMA offers a safer and more effective option than TI because it rarely requires direct laryngoscopy, clearly decreasing this type of trauma and it is one major reason for the observed attenuated pressor responses to LMA.
Laser acupuncture has been identified recently as a method to aid in ameliorating the deleterious effects of endotracheal intubation, especially in pediatric age group.
Superior laryngeal n. and glossopharyngeal n. blocks are also effective methods in blunting adverse hemodynamic responses, which is also appropriate for patient requiring awake TI before anesthetic induction.