Le Dead Volume Calculator is a tool used to determine the residual volume of air or liquid that remains in a system and is not efficiently utilized. It is widely applied in respiratory physiology, liquid storage systems, and laboratory equipment such as pipettes and tubing.
LUMIÈRE SUR NOS volume mort est cruciale dans medical, engineering, and laboratory settings because it helps optimize resource usage, improve efficiency, and minimize waste.
Formula of Dead Volume Calculator
Dead volume calculations vary depending on the application. Below are the clé formulas used in different fields.
1. Dead Volume in Respiratory Physiology
Dead volume in the respiratory system refers to the air that does not participate in gas exchange. It includes anatomique espace mort et les physiological dead space.
Anatomical Dead Space:
Dead Volume = 2.2 mL × Ideal Body Weight (kg)
Physiological Dead Space (Using Bohr’s Equation):
VD = (PaCO2 – PeCO2) / PaCO2 × Tidal Volume (VT)
Où :
- PaCO2 = Arterial CO₂ pressure
- PeCO2 = Expired CO₂ pressure
- VT = Tidal volume (air inhaled/exhaled per breath)
2. Dead Volume in Liquid Storage Systems
In tanks, pipes, or reactors, dead volume is the remaining liquid that cannot be drain. Il est calculé comme suit :
Dead Volume = (Volume du conteneur – Minimum Drainable Volume)
Pour réservoirs coniques, where liquid residue remains at the bottom:
Dead Volume ≈ (π × r² × h) / 3
Où :
- r = Rayon de the conical section
- h = Height of the conical residue
3. Dead Volume in Pipetting or Lab Equipment
In pipettes, tubing, or small lab containers, dead volume refers to the liquid left behind in the system due to internal dimensions.
Dead Volume = (Inner Diameter² × Longueur × π) / 4
Où :
- Diamètre intérieur = Tube or pipette bore size
- Longueur = Section of the tube holding liquid
These formulas ensure accurate dead volume estimation, reducing material loss in industrial and laboratory applications.
Tableau des conditions générales
The following table provides a reference for commonly used terms in dead volume calculations.
| Long | Définition | Exemple de calcul |
|---|---|---|
| PaCO2 (mmHg) | Arterial CO₂ partial pressure | 40 mmHg |
| PeCO2 (mmHg) | Expired CO₂ partial pressure | 30 mmHg |
| VT (mL or L) | Tidal volume (air per breath) | 500 ml |
| Ideal Body Weight (kg) | Standard weight for lung function calculations | 70 kg |
| Volume du conteneur (L) | Total liquid storage capacity | 1000 L |
| Drainable Volume (L) | Volume that can be fully drained | 950 L |
| Rayon (m) | Radius of conical bottom in tanks | 0.5 m |
| Hauteur (m) | Height of the liquid residue | 0.2 m |
| Diamètre intérieur (mm) | Bore size of a pipette or tubing | 2 mm |
| Longueur du tube (cm) | Length of the liquid-filled tube | 10 cm |
This table helps in quickly understanding common dead volume factors à travers différentes applications.
Example of Dead Volume Calculator
Example 1: Dead Volume in Respiratory Physiology
A patient with an ideal body weight of 70 kg a anatomical dead space calculated as:
Dead Volume = 2.2 × 70
Dead Volume = 154 ml
Pour physiological dead space, si:
- PaCO2 = 40 mmHg
- PeCO2 = 30 mmHg
- Volume courant = 500 ml
Using Bohr’s Equation:
VD = (40 – 30) / 40 × 500
VD = (10 / 40) × 500 = 125 ml
Ainsi, 125 ml of each breath is wasted due to dead space.
Example 2: Dead Volume in Liquid Storage Tanks
For a conical tank with:
- Radius = 0.5 m
- Height of residual liquid = 0.2 m
Dead Volume = (π × 0.5² × 0.2) / 3
Dead Volume = (3.1416 × 0.25 × 0.2) / 3 = 0.0523 m³ = 52.3 L
En d'autres termes, 52.3 litres of liquid cannot be drained.
Example 3: Dead Volume in Pipettes
For a tube with:
- Inner Diameter = 2 mm (0.002 m)
- Length = 10 cm (0.1 m)
Dead Volume = (0.002² × 0.1 × π) / 4
Dead Volume = 3.14 × 10⁻⁷ m³ ≈ 0.314 µL
This means the pipette retains 0.314 XNUMX microlitres de liquide.
FAQ les plus courantes
Dead volume is crucial in assessing lung efficiency and optimizing ventilator settings. Increased dead space can lead to poor oxygen exchange and respiratory distress.
In tanks and pipes, dead volume reduces usable liquid et les increases material waste. Proper design helps minimize this effect.
Oui, low-retention pipettes and proper technique help minimize liquid retention, improving accuracy in expériences de laboratoire.