Is a chest tube output of 5ml per hour 8 hours after surgery considered acceptable?

Chest Tube Output of 5ml/hour at 8 Hours Post-Surgery is Acceptable

A chest tube output of 5ml per hour (40ml over 8 hours) is well within normal limits and does not require intervention. This minimal drainage volume is far below any threshold that would raise concern for complications or warrant chest tube removal delays.

Expected Drainage Patterns After Surgery

Normal Post-Cardiac Surgery Drainage

• Traditional practice typically removes chest tubes when drainage is 100-200 mL per 24 hours, though this threshold lacks robust validation 1
• Studies in thoracic surgery demonstrate safety with higher thresholds up to 450-500 mL/day 2, 1
• Your patient's output of 5ml/hour (120ml/24 hours if sustained) falls comfortably within acceptable ranges 1

Critical Thresholds to Monitor

• Concerning drainage is defined as >200 mL/hour or >1000 mL in the first 12 hours, requiring immediate surgical notification 2
• Hemorrhagic drainage (bright red blood or sudden increase in bloody output) requires urgent intervention 2
• Your patient's minimal output of 5ml/hour is approximately 40-fold lower than the concerning threshold 2

What Matters More Than Volume Alone

Character of Drainage

• The character of fluid (serous versus bloody) matters more than volume alone 1
• Serous fluid at low volumes like 5ml/hour indicates normal postoperative drainage 2, 1
• Sudden increases in volume or change to bloody drainage would be more concerning than stable low output 2

Hemodynamic Stability

• Assess for signs of hypovolemic shock including tachycardia >100 bpm, systolic BP <90 mmHg, decreased urine output <0.5 mL/kg/hour 2
• With minimal drainage of 5ml/hour, hemodynamic instability would be unexpected unless there is occult bleeding not captured by the chest tube 2

Clinical Decision-Making at This Point

Continue Monitoring

• Monitor drainage volume, character, and clinical status continuously 1
• Document hourly output for the first 4-6 hours, then every 2-4 hours 2
• At 5ml/hour, your patient is trending toward early chest tube removal criteria 2, 1

Chest Tube Removal Criteria

• Drainage <450 mL/day of serous fluid is a safe threshold for chest tube removal 2
• Air leak <20 mL/min for 6 hours (if using digital system) or no bubbling in water seal for 6 hours 2
• Hemodynamic stability maintained for >12 hours 2
• Your patient's 5ml/hour output (120ml/24 hours projected) already meets the drainage criterion 2

Important Caveats

Avoid Premature Removal

• Early chest tube removal (within 24 hours) when output is <150ml in last 4 hours is associated with increased risk of pleural/pericardial effusions requiring reintervention (adjusted RR 1.70,95% CI: 1.24-2.33) 3
• Even with low output, waiting until postoperative day 1 morning rather than removing tubes on day of surgery reduces complications 3

Do Not Focus Solely on Volume

• Do not focus solely on drainage volume without assessing character, hemodynamics, and trend over time 2
• Sudden increases are more concerning than stable high output 2
• Do not remove chest tubes with ongoing air leak, regardless of fluid volume 2

Fluid Management Considerations

• Do not administer liberal IV fluids (>3 L in the first 24 hours) as this increases risk of acute lung injury with mortality up to 50% after lung resection 2
• Avoid positive fluid balance >1.5 L in the first 24 hours to prevent pulmonary edema 2