Physics: Temperature and Gas Laws

Questions and Answers

What is the formula to convert Fahrenheit to Celsius?

°C = (°F - 32) / 1.8

What is the formula for Cardiac Output (QT)?

QT = SV x HR

What is the formula for Stroke Volume (SV)?

SV = QT / HR

What is Boyle's Law?

(P1 x V1) = (P2 x V2) Signup and view all the answers

What is Charles' Law?

V1/T1 = V2/T2 Signup and view all the answers

What is Gay-Lussac's Law?

(P1/T1 = P2/T2) Signup and view all the answers

What does the Ideal Gas Law state?

(P1 x V1)/T1 = (P2 x V2)/T2 Signup and view all the answers

What is the formula for the partial pressure of oxygen in the atmosphere?

PiO2 = FiO2 x PB Signup and view all the answers

How do you calculate the subtraction of water vapor pressure at 37 degrees when fully saturated?

H2O vapor saturated - Body humidity = 47mm Hg or 43.8mg/L Signup and view all the answers

What is the formula for the partial pressure of oxygen in the lungs?

PIO2 = FIO2 x PB Signup and view all the answers

What is the formula for Total Cycle Time (TCT)?

TCT = 60/RR Signup and view all the answers

What does the I:E Ratio represent?

1: Te/Ti Signup and view all the answers

What does the Inverse I:E Ratio indicate?

Inspiratory time is more than expiratory time. Ti/Te :1 Signup and view all the answers

What are the formulas for Inspiratory Time (Ti) and Expiratory Time (Te)?

Ti = TCT/#, Te = TCT - Ti Signup and view all the answers

What is the formula for Static Compliance (Cs)?

Cs = Vt/Plat - PEEP Signup and view all the answers

What is the formula for Dynamic Compliance (Cd)?

Cd = Vt/PIP - PEEP Signup and view all the answers

How is Relative Humidity (%RH) calculated?

%RH = (Absolute humidity)/(Humidity capacity) x 100 Signup and view all the answers

To find the total flow of a venture mask system, you need to add both parts of the Air:O2 ratio together and multiply by the given oxygen flow set. What is this total flow called?

Total flow Signup and view all the answers

What is the formula for the Oxygen Entrainment Ratio?

Air/O2 = (100 - Desired O2)/(Desired O2 - 21*) Signup and view all the answers

What is Minute Ventilation (Ve) calculated as?

Ve = RR x VT Signup and view all the answers

How is the Peak Inspiratory Flow (Vi) determined?

Vi = Ve (3) Signup and view all the answers

What is the formula for Tank Duration of Flow for an H Tank?

Cylinder pressure (psi) x Cylinder factor / Flow rate of gas (L/min), H tank = 3.14 Signup and view all the answers

What is the formula for Duration of Flow for an E Tank?

{Cylinder pressure (psi)} x {Cylinder factor}/{Flow rate of gas (L/min)}, E tank = 0.28 Signup and view all the answers

What is the Ideal Body Weight Formula (IBW) in pounds for adult males?

Male: 106 + (height - 60 x 6) Signup and view all the answers

What is the Ideal Body Weight Formula (IBW) in kilograms for adult males?

Men: 50 + 2.3 x (Ht - 60) Signup and view all the answers

What does a 1% solution equate to in terms of mg?

1g = 1000mgs in 100ml, 10mg/ml Signup and view all the answers

How do you calculate the mg/ml for a 10% solution?

10g = 10000mg/100ml = 100mg/ml Signup and view all the answers

What is the mg/ml for a 1:10000 solution?

0.1mg/1ml Signup and view all the answers

What is the formula established for Anatomic Deadspace?

1ml per pound of body weight Signup and view all the answers

What is the Physiologic Deadspace (Bohr Equation)?

Vd/Vt = PaCO2 - PeCO2/PaCO2 Signup and view all the answers

What is the formula for Alveolar Ventilation (Va)?

Va = Ve - Vd Signup and view all the answers

How is % Predicted calculated?

% Predicted = (Actual FVC/Predicted FVC) X 100 Signup and view all the answers

What is the formula for calculating % Change?

% Change = (Post value - Pre value)/ Pre value X 100 Signup and view all the answers

What is the definition of Patient Effort in respiratory terms?

FEV1 x 35 Signup and view all the answers

What is the Ideal Alveolar Gas Equation (PAO2)?

PAO2 = [PB - PH2O]FIO2 - PaCO2 (1.25) Signup and view all the answers

What does Fick's Law describe?

V (diffusion) gas = AD(P1 - P2)/T Signup and view all the answers

What is the formula for Oxygen content of arterial blood (CaO2)?

CaO2 = (Hb x 1.34 x SaO2) + (PaO2 x 0.003) Signup and view all the answers

What is the formula for Oxygen Content of Pulmonary Capillary Blood (CcO2)?

CcO2 = (Hb x 1.34) + (PAO2 x 0.003) Signup and view all the answers

What is the formula for Oxygen content of mixed venous blood (CvO2)?

CvO2 = (Hb x 1.34 x SvO2) + (PvO2 x 0.003) Signup and view all the answers

What is the formula for pulmonary shunt (Qs/Qt)?

Qs/Qt = % Pulmonary shunt CcO2 - CaO2/CcO2 - CvO2 Signup and view all the answers

How do you calculate total oxygen delivery (DO2)?

DO2 = QT x (CaO2 x 10) Signup and view all the answers

What is the formula for oxygen consumption (VO2)?

VO2 = QT (CaO2 - CvO2) x 10 Signup and view all the answers

What is the Oxygen Extraction Ratio (O2ER)?

ERO2 = (CaO2 - CVO2) / CaO2 Signup and view all the answers

How much dissolved oxygen is there in blood for each mmHg of PO2?

0.003 ml O2 will dissolve in 100 ml of blood Signup and view all the answers

What is Hemoglobin's carrying capacity and saturation?

1.34ml of O2 per g%, 15g% = 100% Hb sat, 1.34 x 15 = 20.1 vol% Signup and view all the answers

What is the formula for Airway Resistance (Raw)?

Raw = PIP - PLAT/Flow Signup and view all the answers

What is the formula for FIO2 when determining desired PaO2?

FIO2 = PaO2 Desired x FiO2 known/ PaO2 Signup and view all the answers

What is the formula for Ve when determining desired PaCO2?

Ve = Known PaCO2 x known Ve/Desired PaCO2 Signup and view all the answers

What is the formula for RR when determining desired PaCO2?

RR = Known PaCO2 x known RR/Desired PaCO2 Signup and view all the answers

What is the formula for Vt when determining desired PaCO2?

Vt = Known PaCO2 x known Vt (ml)/Desired PaCO2 Signup and view all the answers

What is Poiseuille's Law for Flow?

Flow = Change in Pressure (P) x r^4 Signup and view all the answers

What is Poiseuille's Law for Pressure?

Change in Pressure (P) = Flow/r^4 Signup and view all the answers

What is the formula for Time Constants (Tc)?

Tc = Raw x Cd Signup and view all the answers

Study Notes

Temperature Conversion

Fahrenheit (°F) can be converted to Celsius (°C) using the formula: °C = (°F - 32) / 1.8.

Cardiac Measurement

Cardiac Output (QT) is determined by multiplying Stroke Volume (SV) with Heart Rate (HR): QT = SV x HR.
Stroke Volume (SV) is calculated by dividing Cardiac Output by Heart Rate: SV = QT / HR.

Gas Laws

Boyle's Law states that the product of pressure (P) and volume (V) remains constant when temperature is unchanged: (P1 x V1) = (P2 x V2).
Charles' Law relates volume and temperature with a constant pressure: V1/T1 = V2/T2.
Gay-Lussac's Law connects pressure and temperature with a constant volume: P1/T1 = P2/T2.
The Ideal Gas Law combines pressure, volume, and temperature: (P1 x V1)/T1 = (P2 x V2)/T2.

Pressure and Humidity Calculations

The partial pressure of oxygen in the atmosphere is given by: PiO2 = FiO2 x PB.
To account for water vapor pressure at 37 degrees Celsius, the equation is: H2O vapor saturated - Body humidity = 47 mm Hg or 43.8 mg/L.
The partial pressure of oxygen in the lungs is calculated similarly: PIO2 = FIO2 x PB.

Respiratory Ratios and Timings

Total Cycle Time (TCT) can be calculated by dividing 60 by Respiratory Rate (RR): TCT = 60/RR.
The Inspiratory:Expiratory (I:E) Ratio is defined as 1: Te/Ti, and an inverse I:E ratio indicates longer inspiratory time compared to expiratory time: Ti/Te :1.
Inspiratory Time (Ti) can be calculated as Ti = TCT/#, while Expiratory Time (Te) is determined as Te = TCT - Ti.

Compliance Measurements

Static Compliance (Cs) can be calculated with the formula: Cs = Vt / (Plat - PEEP).
Dynamic Compliance (Cd) is calculated as: Cd = Vt / (PIP - PEEP).

Humidity and Flow Rates

Relative Humidity (%RH) is calculated by dividing absolute humidity by humidity capacity and multiplying by 100: %RH = (Absolute humidity)/(Humidity capacity) x 100.
The total flow of a venturi mask system can be derived by finding the sum of both Air:O2 ratios and multiplying by the oxygen flow set.

Oxygen Entrainment and Ventilation

The Oxygen Entrainment Ratio is determined using the equation: Air/O2 = (100 - Desired O2)/(Desired O2 - 21*), with a stipulation to use 20% if the desired O2 is greater than 35%.
Minute Ventilation (Ve) is calculated as: Ve = RR x VT.
Peak Inspiratory Flow (Vi) is determined using: Vi = Ve (3).

Flow Capacity and Duration

Tank duration for an H tank is calculated using: Cylinder pressure (psi) x Cylinder factor/Flow rate of gas (L/min) with H tank = 3.14.
For an E tank, it is: {Cylinder pressure (psi)} x {Cylinder factor}/{Flow rate of gas (L/min)} with E tank = 0.28.

Body Weight Calculations

The Ideal Body Weight formula in pounds: Male: 106 + (height - 60 x 6), Female: 105 + (height - 60 x 5).
In kilograms, the IBW formula is: Men: 50 + 2.3 x (Ht - 60), Women: 45.4 + 2.3 x (Ht - 60).

Solution Concentration

A 1% solution converts to 10 mg/ml, while a 10% solution equals 100 mg/ml.
A ratio such as 1:10000 translates to 0.1 mg/ml.

Deadspace and Ventilation Calculations

Anatomic Deadspace is approximately 1 ml per pound of body weight.
Physiologic Deadspace (Bohr Equation): Vd/Vt = (PaCO2 - PeCO2)/PaCO2, where Physiologic VD = Anatomic VD + Alveolar VD.
Alveolar Ventilation (Va): Va = Ve - Vd, or Va = (Vt - Vd) (RR).

Predicted Values

% Predicted: % Predicted = (Actual FVC/Predicted FVC) x 100.
% Change: % Change = (Post value - Pre value)/ Pre value x 100.

Oxygen and Hemoglobin Measurements

Oxygen content in arterial blood: CaO2 = (Hb x 1.34 x SaO2) + (PaO2 x 0.003).
Pulmonary shunt: Qs/Qt = % Pulmonary shunt = (CcO2 - CaO2)/(CcO2 - CvO2).
Fick's Law of diffusion: V (gas) = AD(P1 - P2)/T.

Other Oxygen Metrics

Total oxygen delivery (DO2): DO2 = QT x (CaO2 x 10).
Oxygen consumption/uptake (VO2): VO2 = QT (CaO2 - CvO2) x 10.
Oxygen Extraction Ratio (O2ER): ERO2 = (CaO2 - CVO2) / CaO2.

Airway Resistance and Optimization

Airway Resistance (Raw): Raw = (PIP - PLAT)/Flow, adjusting flow from L/min to L/sec for calculations.
Formulas for FIO2, Ve, RR, and Vt are provided to maintain desired arterial blood gas levels.

Poiseuille's Law

Flow is calculated as: Flow = Change in Pressure (P) x r^4.
Pressure can also be computed using: Change in Pressure (P) = Flow/r^4.

Time Constants

Time Constants (Tc): Tc = Raw x Cd, providing insight into respiratory mechanics.

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Description

This quiz covers essential concepts in physics, including temperature conversion between Fahrenheit and Celsius, cardiac measurements, and various gas laws. You will explore Boyle's Law, Charles' Law, Gay-Lussac's Law, and the Ideal Gas Law, as well as pressure and humidity calculations. Test your understanding of these fundamental principles!