Oxygen Tank Duration and O₂ Tools Calculator for Nurses
E and H/K cylinder duration estimates. Conservative calculations for safety.
Common clinical questions about this calculator and its applications
How do I calculate how long my oxygen tank will last?
Duration = (Tank Pressure × Tank Factor) ÷ Flow Rate. Tank factors: E cylinder = 0.28, D cylinder = 0.16, M cylinder = 1.56, H/K cylinder = 3.14. For example, a full E cylinder (2000 psi) at 2 L/min: (2000 × 0.28) ÷ 2 = 280 minutes ≈ 4.7 hours. Always check pressure gauge before transport and plan for safety margin.
When should I switch from nasal cannula to mask?
Nasal cannula delivers 1-6 L/min (24-44% FiO2). Switch to simple face mask (5-10 L/min, 35-60% FiO2) when patient needs >6 L/min, has significant mouth breathing, or requires higher FiO2. Non-rebreather masks (10-15 L/min, 60-95% FiO2) are for critical hypoxemia. Venturi masks provide precise FiO2 control.
What flow rate do I need for a non-rebreather mask?
Minimum 10 L/min, typically 10-15 L/min. Flow must be high enough to prevent bag collapse during inspiration - the reservoir bag should remain at least 1/3 to 1/2 inflated throughout the respiratory cycle. If bag collapses, increase flow rate. This is critical for maintaining high FiO2.
How accurate is pulse oximetry for assessing oxygenation?
SpO2 is generally accurate ±2-4% when >90%, but less reliable at lower saturations. Factors affecting accuracy include poor perfusion, nail polish, movement, carbon monoxide poisoning, and dark skin pigmentation. Always correlate with clinical assessment and consider arterial blood gas for critical decisions.
What's a safe oxygen saturation target for COPD patients?
Target SpO2 88-92% for COPD patients at risk of hypercapnic respiratory failure (those with previous CO2 retention). Higher oxygen can suppress hypoxic drive in chronic CO2 retainers. However, never withhold oxygen in acute severe hypoxemia - prioritize oxygenation first, then titrate down carefully while monitoring.
About Our Validation & Sources
All calculators on Nurside use evidence-based formulas from standard clinical practice guidelines. Our validation thresholds are derived from clinical experience, published literature, and expert consultation.
Safety Features: Built-in validation catches common entry errors (like unit confusion), flags unusually high or low values, and requires explicit confirmation for potentially dangerous calculations. This is designed to support, not replace, your clinical judgment.
Formula Transparency: Click "Methods Used" in any calculator to see the exact formula and safety thresholds being applied. We believe you should always understand how your clinical tools work.
Educational Purposes Only: These calculators are provided for educational and clinical support purposes. They do not constitute medical advice and should not replace independent clinical judgment. Always verify calculations against your facility's protocols and the patient's specific clinical context.