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1、Hemorrhage that the machinery of life has been rudely unhinged, and the whole system profoundly shocked; in a word, that the nervous fluid has been exhausted” ( A System of Surgery, 1859)1800s Injury to one part of the body results in often fatal effect Strychnine to stimulate NS; seizures Electrica
2、l current alcohol“shock was not a process of dying, rather a marshaling of the bodily defenses in a struggle to live” Realized a fall in BP could account for all symptoms of shock Represents a generalized failure of the body to deliver sufficient amounts of O2 to its tissues S/S represent compensati
3、on measures utilized by the body to maintain delivery of O2 to vital organs Delay of appropriate therapy, cascade of events results in damage to organsTreatment GoalsRecognition of early shock Appropriate airway management Rapid transportation to appropriate facilityHemorrhage Circulatory System Hem
4、orrhage Classification Clotting Factors Affecting Clotting Hemorrhage Control Stages of Hemorrhage Hemorrhage Assessment Hemorrhage ManagementCardiovascular System Delivery of nutrients and O2 to tissues and cells Transportation of waste products produced by metabolism to liver and kidneys Delivery
5、of CO2 to lungsComponentsHeart or pump Blood vessels or pipes Blood or fluidCirculatory System Review Terminology Stroke Volume Preload Ventricular Filling Frank-Starling Mechanism Afterload Cardiac OutputSVxHR=CO5L/min Fick Principle Heart Parasympathetic Nervous SystemSlows rateVagus Nerve Sympath
6、etic Nervous SystemIncreases rateCardiac PlexusCardiac Output Volume of blood pumped in 1 minute = 4-6L SV x HR SV = amount of blood ejected from left ventricle with each contractionBlood Pressure Directly proportional to the product of the CO multiplied by SVR BP = CO x SVR SVR, resistance to flow
7、in the system (systemic vascular resistance)Stroke Volume Preload Represents filling of the ventricle Volume of blood delivered to atria prior to ventricular diastole Dependent on venous return Afterload Amount of resistance heart must overcome to eject blood Contractility Ability to contract, inotr
8、opy Frank Starlings LawInotropy Negative Scar tissue, CHF Beta adrenergic blockers Calcium channel blockers Positive Beta adrenergic agonists, B1 List some B blockers, Ca channel blockers, B agonists Names Indications Contraindications What would you expect to see if you administered this medication
9、? Why?Fick Principle Factors necessary for systemic O2 delivery Ability of O2 to diffuse across alveolar membrane into blood stream Adequate number of RBCs to transport O2 Adequate blood flow to transport RBCs Ability of RBCs to off-load O2O2 Delivery Normal circumstances body extracts about 20% of
10、O2 and 80% returned to heart for reoxygenation Normal ratio of delivered to consumed 5:1 Shock may increase extraction to 50% Ratio drops to 2:1Cellular Metabolism Glycolysis Krebs Cycle Electron TransportGlycolysis Occurs in cytoplasm Glucose converted to pyruvic acid 2 ATP created O2 present furth
11、er aerobic metabolism No O2 present, hypoperfusion, pyruvic acid converted to lactic acid Liver converts some lactic acid Generalized shock Amount of lactic acid exceeds the livers ability to convert it Muscle and skin can function in aerobic conditions for short period Brain most sensitive to hypox
12、iaKrebs CycleAerobic conditions pyruvic acid enters mitochondria Produces 6 CO2 molecules and 4 ATPElectron Transport Occurs in proteins bound to mitochondrial membrane Additional 32 ATP produced Primary site of O2 utilization within cell Produce very little ATP on anarerobic conditionsCellular Meta
13、bolism Two Step Process GlycolysisCell utilizing energy sourceReleases energy Aerobic Metabolism: 95% of cellular EnergyRequires oxygen and glucoseKrebs cycle (citric acid cycle) Uses carbohydrates, proteins and fats to release energy Other Processes Anaerobic MetabolismInadequate oxygen pathwayBypr
14、oducts: Pyruvic Acid Lactic AcidCellular death eventually occurs due to inadequate perfusionCirculatory System Vascular System ArteriesTunica AdventitiaTunica MediaTunica Intima Arteriole Capillary: 7% of blood volume Venule VeinConstriction returns 20% (1 L) of blood to active circulation13% of blo
15、od volume64% of blood volumeBlood Vessels Sympathetic innervation Vasoconstriction Alpha 1 agonist List some drugs that have alpha 1 agonsist/ blocker effects Names Indications Contraindications What physiological response would you expect? Why?Hydrostatic and Oncotic Pressure Two opposing forces that control net flow of fluid and nutrients out of proximal capillaries and flow of waste products and fluid into distal capillaries Hydrostatic pressure Pressure of fluid (BP) serves to drive fluid out of capillary into
