How To Understand The Physiology Of Transport

Transcription

1 Transport Physiology OBJECTIVES 1) Define the gas laws as related to patient transport 2) Identify physiological stressors of air and ground transport 3) Identify measures that can minimize stressors of transport RATIONALE Transport of patients by air or ground involves consideration of the stressors affecting those ill or injured individuals for whom we care. 1

2 RATIONALE These patients are physiologically compromised such that the events impacting them during the transport process might adversely effect their outcomes. RATIONALE Physiology of transport merits consideration when determining the best patient care outcomes. THE EARTH S ATMOSPHERE Gasses of the atmosphere: Nitrogen 78% Oxygen 21% Other Argon, Carbon Dioxide, Neon, Helium, Krypton, Xenon, Hydrogen, Ammonia 2

3 THE EARTH S ATMOSPHERE Atmospheric pressure (Barometric Pressure): The weight or force exerted by any given point in the atmosphere PSI, or mmhg, or inhg GAS DISTRIBUTION RELATED TO: Altitude: Air denser at lower altitudes which means there is a greater pressure change at lower altitudes Latitude: Cooler temps at poles = greater gas density Higher temps near equator = decreased density of gasses PHYSIOLOGIC ZONES OF THE ATMOSPHERE Efficient zone: Sea Level to 10,000ft Middle ear or sinus problems Barometric pressure ~ mmHg Adaptation 3

4 PHYSIOLOGIC ZONES OF THE ATMOSPHERE Deficient zone: 10,000 to 50,000ft Trapped gas expansion and hypoxia Barometric pressure ~ mmHg Supplemental oxygen PHYSIOLOGIC ZONES OF THE ATMOSPHERE Space equivalent zone: 50,000ft and beyond Incompatible w/life Armstrong s Line 63,000ft, the atmospheric pressure ~ 47mmHg which reduces the boiling point of body fluids to

5 THE GAS LAWS Boyle s Law Charles Law Dalton s Law Henry s Law Gay-Lussac s Law Universal Gas Law The volume of a gas is inversely proportional to the pressure to which the gas is exposed 5

6 BOYLES LAW TRANSPORT CONSIDERATIONS BOYLE S LAW Trapped gas IV fluids Endotracheal tube cuffs Pneumatic air splints Mechanical ventilators Pressure sensitive medical equipment TRANSPORT CONSIDERATIONS BOYLE S LAW Middle Ear Barotitis Media Sinuses Barosinusitis Teeth Barodontalgia GI tract Barogastralgia 6

7 The volume of a gas is directly proportional to the absolute temperature of that gas 7

8 CHARLE S LAW Temperature decreases by 2 C (1.8 F) for every 1000 ft increase in altitude. Standard Lapse Rate. TRANSPORT CONSIDERATIONS CHARLES LAW The pressure exerted by a mixture of non-reacting gasses is equal to the sum of the partial pressures of that gas. 8

9 TRANSPORT CONSIDERATIONS DALTON S LAW The quantity of gas dissolved in a solution is directly proportional to the pressure of that gas over the solution. 9

10 TRANSPORT CONSIDERATIONS HENRY S LAW Decompression sickness: Bends Chokes Parasthesias CNS Disorders Nitrogen bubbles become trapped in the joints. Mild onset of symptoms that become painful. 10

11 Nitrogen bubbles block smaller pulmonary vessels which leads to a burning sensation in sternum. The patient may have an uncontrollable desire to cough. The sense of suffocation ensues. Nitrogen bubbles form along nerve tracts. Tingling, an itchy sensation, and possibly a mottled red rash will occur Nitrogen bubbles affect spinal cord leading to visual disturbances, paralysis, one sided tingling. 11

12 HENRY S LAW - TREATMENT Rapid descent 100% oxygen Splint affected limbs Transport to a facility with hyperbaric therapy The pressure of a gas within a constant volume is proportional to it s absolute temperature. 12

13 Takes into account the pressure, volume, and temperature as it relates to gas dynamics. 13

14 PHYSIOLOGIC STRESSORS OF FLIGHT Gastrointestinal tract Ears Facial Sinuses Teeth Extremities 14

15 The Middle Ear ASCENT The Middle Ear DESCENT 15

16 Hypoxic hypoxia = Insufficient available oxygen (flight) Hypemic hypoxia = Reduced oxygen-carrying capacity (trauma, medical, poisoning, meds) Stagnant hypoxia = Inadequate circulation (restriction, pooling, posture) Histotoxic hypoxia = Interference with oxygen use (cyanide, co) 16

17 Cold - Vasoconstriction - Piloerection - Decreased perspiration - Increased muscle activity / shivering - Increased metabolism Heat - Radiation: from substance itself - Conduction: direct contact - Convection: air blowing over - Evaporation: warmer air temp Effects are dependent upon Intensity Duration Rate of onset Body area and site Impact direction 17

18 Humidity is greatest at sea level and low altitudes Air is usually driest at high altitudes and inside transport vehicles Sound is measured in three ways: Frequency (hertz) Intensity (decibels) Duration (time) Inaccurate perception of position, altitude, and motion Opposite of equilibrium Tx w/visual horizon 18

19 All modes of transport S/S increased HR, RR, metabolism, increased oxygen demand = hypoxia End product of all the physiologic stressors of transport Acute vs: chronic Hypoxia Self imposed stressors: Drugs Exhaustion Alcohol Tobacco Hypoglycemia D-E-A-T-H 19

20 Jet fuel vapors Flicker Vertigo Third spacing KEY POINTS Boyle s law is basic/important Physiology impacts both the patient and transport team. Fatigue kills Mitigating transport stressors is essential for positive patient outcomes. QUESTIONS? 20