Equations for Primary FRCA

Transcription

1 Equations for Primary FA Pharmacology : concentration t: time Bioavailability Bioavailab ility AU AU OAL IV AU: area under concentration time curve Exponential Function d d or K. dt dt e.78 or e O. e Kt (for a negative exponential relationship) O is the concentration at t 0 K: rate constant Pharmacodynamics D: free drug : unoccupied receptors D: drug occupied receptors K D : dissociation constant [ D][ ] K D [ D] affinity K D Enzyme Kinetics

2 V V K max[ m + S] [ S] V: initial velocity V max : maximum initial velocity K m : concentration at which the initial velocity is half the maximal initial velocity S: substrate Pharmacokinetics l: clearance Vd: volume of distribution τ: time constant K: rate constant D: dose Vd D 0 τ K el Vd τ l t τ log e Loading dose Vd. p Maint enance dose p. l hree ompartment Model p αt γt A. e + G. e + B. e βt A/α B/ β G/γ: kinetic constants Physics and Measurement: Pressure & Fluids Pressure

3 Pr essure force area Absolute pressure gauge pressure + atmospheric pressure Fluids Q: flow d: tube diameter P: pressure η: viscosity l: length of tube v: fluid velocity p: density Laminar flow. Hagen-Poiseuille Equation 4 πpd Q 8η l eynolds Number vpd η urbulent Flow Q Q Q P l p Bernoulli s Equation pv + P K P: potential energy Physics and Measurement: Gas Laws

4 P: pressure V: volume : temperature K: constant Boyle s Law: PV K harles Law: V K 3 rd P Law: K PV K PV n n: number of moles : universal gas constant Physics and Measurement: Electricity V: potential difference (volts) I: current (amps) : resistance (ohms) V I Power Power (watts) VI I harge Q amperes( A) seconds( s) Q: charge (coulombs) apacitance Q V : capacitance (farads) Defibrillator

5 Stored Energy esistors V Parallel: +... Series: +... QV Wheatstone Bridge: 3 4 Physics and Measurement: Other ension : tension : radius P: pressure gradient ube: P r Sphere: P r Work Work done force X distance Unit of work Nm Humidity elative humidity Linear Function y Mx + M: gradient of a straight line : y axis intercept actual vapour pressure saturated vapour pressure

6 Light Lambert-Bouguer law I I e O ad I: transmitted light I O : incident light a: extinction coefficient for the solution d: thickness Lambert-Beer law Absorbance ξcd ξ: molar extinction coefficient c: molar concentration d: thickness Physics and Measurement: Statistics ( ) x x Variance SD n Standard Error of the Mean SD n SD: standard deviation Physiology: cellular Diffusion A Q k ( ) p Q: rate of diffusion k p : permeability constant A: area of membrane : thickness of membrane permeability solubility MW

7 : concentration gradient otal Blood Volume (V BL ) V PL 00 (00 Hct) V PL : volume plasma Hct: haematocrit Measurement of Fluid ompartments mass of indicator volume of compartment concentration in compartment Osmotic Pressure (van t Hoff equation) π π: osmotic pressure : universal gas constant : absolute temperature : osmolality (mosm/kg H O) Plasma Osmolality Plasma Osmolality (mosm/kg H O) [Na] + [glucose] + [urea] Gibbs-Donnan [ cation ] [ anion] [ cation] [ anion] A A B B Nernst Equation For example, sodium: capillary wall potential (mv) : universal gas constant : absolute temperature F: Faraday constant Z: valency Int: interstitial c: capillary Starling Forces FZ Na [ Na] int loge [ Na]

8 Pressure Gradient ate of (P + π ( P + π ) Int ) Int π Int ) ( Int + π Filtration K (P + P π: colloid osmotic pressure P: hydrostatic pressure Int: interstitial c: capillary ) Physiology: ardiac SV: stroke volume O: cardiac output SV: systemic vascular resistance (dynes.s/cm 5 ) BP: blood pressure (mmhg) MAP: mean arterial blood pressure H: heart rate VP: central venous pressure (mmhg) Stroke Volume SV EDV ESV Ejection Fraction SV EDV EDV: end diastolic volume ESV: end systolic volume ardiac Output O H SV ardiac Index O BSA BSA: body surface area Systemic Vascular esistance SV MAP VP 80 O Mean Arterial Blood Pressure MAP VP O SV

9 Q interval corrected (Q c ) Q c Q -: interval between two consecutive waves Fick Method O V O ( ao ) vo VO : oxygen uptake ao : oxygen content of arterial blood vo : oxygen content of venous blood Physiology: espiratory V : volume of gas per unit time V: volume of gas D: dead space : content P: pressure or partial pressure Ventilation V V + V A D V O V A K PAO Bohr equation VD PAO PEO V PAO (for physiological dead space) Alveolar Gas Equation PAO PAO PIO

10 V O : respiratory quotient VO Venous to Arterial Shunt QS Q co ao co vo Q: volume of blood per unit time S: shunt : total c: end capillary ompliance compliance ΔV ΔP L + W : respiratory system compliance L : lung compliance W : wall compliance Oxygen ontent % sat ontent (ml O / g Hb) (.39 [Hb] ) + (0.03 Po) 00 Po : partial pressure in kpa Physiology: Other learance U xv x Px x : clearance of x (ml/min) U x : urine concentration of x P x : plasma concentration of x V: urine flow (ml/min) pk

11 pk log K + [ H ][ A ] k [ HA] Henderson-Hasselbach [ conjugate base] ph pk + log [ acid] ph ph [ HO3 ] pk + log [ H O ] [ HO3 ] pk + log 0.3 Pco erebral Perfusion Pressure PP MAP ( IP + VP) 3