Inhalational Anaesthesia Cost Simulator

Agent — ISO vaporiser colour code

Gas circuit

N₂O — Blue cylinder (India) ■ D-type · 30 kg · 16 395 L at 20 °C · ₹6 000 refill · ₹0.3660/L · ₹200/kg

Fresh gas flows (L/min)

O₂ (L/min)

Air (L/min)

N₂O (L/min) Enable N₂O+O₂ circuit above

Total FGF

Patient physiology & VO₂ (Brody · Kleiber's Law)

Weight (kg) Neonates 0.5–3 kg · Children to 70 kg

Age

Adult Mapleson 1996 · max 120 yr

VO₂ — Brody (mL/min) 10 × W^0.75 · Kleiber's Law

Age-adjusted MAC Standard (age 40)

RQ 0.82 VCO₂ — mL/min O₂ consumed — mL/min MAC multiplier —

Sidestream capnograph gas loss (non-return systems — excludes Dräger Perseus/Apollo, GE Aisys)

Custom loss (mL/min)

FiO₂ — steady-state approximation (VO₂ + capno; simplified; not a full circle uptake model)

—%

02125304060100%

✓ FiO₂ safe

O₂: —

ⓘ

FGF within recommended range

Flow strategy	FGF range	Max acceptable leak	Capnograph impact
HIGH FLOW	> 3.0 L/min	< 300 mL/min	Capno / leak negligible vs FGF
MEDIUM FLOW	2.0 – 3.0 L/min	< 200 mL/min	Capno 150–200 mL/min = 5–10% FGF
LOW FLOW	0.75 – 2.0 L/min	< 150 mL/min	50–100 mL/min = 5–13% of FGF
MINIMAL FLOW	< 0.75 L/min	< 50 mL/min	Capno 150–200 mL/min exceeds limit
CLOSED CIRCUIT	= Metabolic demand	< 20 mL/min	Any capno/leak must be compensated by FGF

Measured circuit leak (mL/min)

Enter measured leak above

Leak test: APL closed, FGF = 0, observe bag/bellows volume loss per minute. Ref: Baum J. Low Flow Anaesthesia 2nd ed. · Closed circuit ≈ VO₂ demand ×1.2 (safety margin); N₂O uptake not separately modelled

Vaporizer & timing

Dial setting (%) Max 8% (Sevoflurane vaporizer)

Duration (minutes)

Altitude (atm) 1.000 = sea level · Varanasi ≈ 1.000

Volatile agent price — India 2026

₹ per 250 mL bottle Inst: Sevorane/Kelsevo tender rate

₹ per mL agent (derived)

₹ per kg N₂O D-cyl 30 kg refill ≈ ₹6 000 → ₹200/kg

Price mode active

Agent	Institutional ₹/250mL	Retail MRP ₹/250mL	Common brands
Sevoflurane	₹ 3,500	₹ 8,500	Sevorane (Abbott), Kelsevo (Celon), Sevitrue
Isoflurane	₹ 500	₹ 1,200	Forane (Abbott), Aerrane (Baxter), Isifrane, Piramal
Desflurane	₹ 5,000	₹ 9,500	Suprane 240 mL (Baxter) — only brand in India
Halothane	₹ 400	₹ 700	Fluothane (Piramal) — limited availability

Prices as of 2026 · Institutional = tender/contract rate · Retail = open market/chemist MRP · Desflurane pack is 240 mL (Suprane); price shown normalized to 250 mL equivalent

Sodalime — amortized separately (India: 5 L can standard)

₹ per can / cartridge Drägersorb 800+ 5 L · ₹1850–2250

Can / cartridge volume (L) Standard India hospital pack = 5 L

Patient VCO₂ (mL/min) ← VCO₂ = VO₂ × RQ 0.82 · edit to override

Can life (derived)

Product	Pack	₹ Institutional	CO₂ cap (L/L)	Indicator
Drägersorb 800+	5 L	₹ 2,000	221	White → Violet-blue
Intersorb Plus	5 L	₹ 1,800	265	Pink → White (exhausted)
Drägersorb CLIC	1.2 L	₹ 550	221	White → Violet (single use)

CO₂ capacity: Drägersorb 260 mL/g × 850 g/L bulk density = 221 L CO₂/L · Intersorb 265 mL/g × 1000 g/L = 265 L CO₂/L · Source: manufacturer data; Moody et al. Med Gas Res 2020

Sevoflurane — per-minute consumption & cost

Vapor output

—

mL vapor / min

Liquid consumed

—

mL liquid / min

Mass consumed

—

mg / min

Agent cost

—

₹ / min

N₂O cost

—

₹ / min

Sodalime cost

—

₹ / min

Total cost / minute

—

agent + N₂O + sodalime (workstation & CMC excluded)

Cost / MAC-hour

—

volatile agent only

MAC fraction delivered

— MAC

—

Cumulative costs — 60 minutes

Volatile liquid consumed—

Fraction of 250 mL bottle—

N₂O consumed—

Sodalime consumed—

Agent cost—

N₂O cost—

Sodalime cost—

Total anaesthetic gas cost—

🌿 Environmental impact — Global Warming Potential (GWP₁₀₀)

Low impact

Agent CO₂-eq / min

—

g CO₂-eq / min

N₂O CO₂-eq / min

—

g CO₂-eq / min (GWP 273)

Total CO₂-eq / min

—

g CO₂-eq / min

Session total CO₂-eq

—

kg CO₂-eq for 60 min

Agent GWP₁₀₀

—

× CO₂ over 100 yr

Equivalent driving

—

km (120 g CO₂/km avg car)

GWP relative to agents (Sevo=1) —

GWP₁₀₀ source: Sulbaek Andersen MG et al. J Phys Chem A 2010 · N₂O: IPCC AR6 2021 (GWP=273) · Sevo 130 · Iso 510 · Des 2540 · Halo ~40 (approximate — limited atmospheric measurement data) · Sherman J et al. Anesth Analg 2012;114:1086 · McGain F et al. Anaesth Intens Care 2021

Agent physical properties & MAC — reference

† mL vapour per mL liquid at 20 °C, 1 atm — derived: (ρ/MW) × 24 040 mL/mol. MAC: Eger EI, Am J Health Syst Pharm 2004;61(S4):S3–10. N₂O: 1 kg = 546.5 L at 20 °C. Colour codes: ISO vaporiser convention (Dräger / GE / Penlon).

Core formula — ideal gas law at 20 °C, 1 atm (molar volume 24.04 L/mol):

V_vapor (mL/min) = FGF_total (mL/min) × dial% / 100
n (mol/min) = V_vapor / 24 040
m (g/min) = n × MW_agent
V_liq (mL/min) = m / ρ_agent

N₂O: 1 kg → (1 000/44.01) mol × 24.04 L/mol = 546.5 L at 20 °C
Sodalime (g/min) = CO₂_production (mL/min) ÷ capacity (mL CO₂/g)

References:

1. Biro P. Calculation of volatile anaesthetics consumption from agent concentration and FGF. Acta Anaesthesiol Scand 2014;58(8):968–72. PMID 25060161

2. Moody AE et al. Predicting cost of inhalational anaesthesia at low FGF. Med Gas Res 2020;10(2):64–66. PMC7885709

3. Pierce JMT et al. Validation of anaesthetic impact calculator mathematics. Anaesthesia 2020;75(1):112–15. doi:10.1111/anae.14896

4. Eger EI. Characteristics of anaesthetic agents. Am J Health Syst Pharm 2004;61(S4):S3–10.

5. Weinberg L et al. Pharmacoeconomics of volatile agents. Anaesth Intensive Care 2010;38(5). DOI

6. Boldt J et al. Economic considerations: propofol vs volatiles. Anesth Analg 1998;86:504–9. PMID 9495402

7. Odin I, Feiss P. Low flow and economics. Best Pract Res Clin Anaesthesiol 2005;19:399–413.

8. Tollinche L et al. Volatile consumption audit by FGF. Int J Anesthetic Anesthesiol 2018;5:064. Open access

⚠ Workstation purchase price and annual 5% CMC are excluded from amortized cost. Sodalime is an amortized line item separate from agent cost. Cost/MAC-hour is for volatile agent only. Medical oxygen constitutes an essential infrastructure requirement for critical care and anesthesia; consequently, its separate billing is considered unfair business practice under current Indian regulatory guidelines. Disclaimer: This software is intended to be used only for medical education and training. It is not a regulator approved anaesthesia billing software.

Inhalational Anaesthesia Cost Simulator - IACS-v3