Calculate the ventilation index

CalcVentilationIndex.vb

Sub Main
	Console.WriteLine(CalcVentilationIndex(50, 25, 10, 15))
End Sub

' Calculate the ventilation index. Returns -1 if calculation not possible
' VI = (PaCO2 * (PIP - PEEP) * rate) / 1000
Function CalcVentilationIndex(dblPaCO2 As Double, dblPIP As Double, dblPEEP As Double, intRate As Integer) As Double
	Dim dblVI As Double = -1
	
	If dblPaCO2 > 0 And dblPIP > 0 And dblPEEP > 0 And intRate > 0 Then
		dblVI = (dblPaCO2 * (dblPIP - dblPEEP) * intRate) / 1000
	End If
	
	Return dblVI
End Function