One-Lung Ventilation (OLV): Thoracic Anaesthesia Cheat Sheet

For trained anaesthesia clinicians. Follow local thoracic, ICU, and surgical protocols.

1. Physiology of OLV

What changes?

• The non-dependent operative lung is collapsed and not ventilated but remains perfused.
• This creates an obligatory right-to-left intrapulmonary shunt.
• The dependent lung receives all delivered tidal volume and is prone to:
  • Atelectasis from lateral positioning, anaesthesia, paralysis, mediastinal compression, and secretions
  • Barotrauma/volutrauma if tidal volume or pressures are excessive
  • Hyperinflation and auto-PEEP, particularly in COPD

1. Perfusion of the non-ventilated lung, producing shunt.
2. Atelectasis or low V/Q in the dependent ventilated lung.
   Miller’s Anesthesia, 10e, p. 1318.

Hypoxic pulmonary vasoconstriction (HPV)

• Hypoxia in the collapsed lung causes local pulmonary arteriolar constriction.
• Blood is diverted toward the oxygenated dependent lung.
• HPV begins within seconds, has an early phase over minutes, and reaches substantial effect by about 15-20 minutes.
• Despite HPV, shunt during OLV commonly remains around 20%-30%.

Factors that worsen oxygenation / inhibit HPV

• Hypoxia in the dependent lung
• Excessive airway pressure, excessive PEEP, hyperinflation
• Hypotension or low cardiac output
• Severe anaemia or low mixed venous oxygen saturation
• Excessive volatile anaesthetic concentrations
• Vasodilators delivered systemically
• Nitrous oxide
• Pulmonary vasodilators reaching the non-ventilated lung

2. Preoperative Assessment

Assess respiratory reserve

• Symptoms, exercise tolerance, recent infection/exacerbation, smoking, home oxygen, OSA.
• Spirometry and DLCO where lung resection is planned.
• ABG if severe disease, hypercapnia, hypoxaemia, or concern about CO2 retention.
• CT: tumour location, airway distortion, bullae, pleural adhesions, bronchial obstruction.
• Consider perfusion scan or predicted postoperative FEV1/DLCO for major resection.

Identify patients likely to desaturate during OLV

• Poor baseline oxygenation
• Low FEV1/DLCO, severe COPD, interstitial lung disease
• Contralateral lung disease
• Right-sided thoracic surgery, because the non-ventilated right lung usually represents more perfused lung
• Obesity
• Previous contralateral lung resection
• Pulmonary hypertension or impaired RV function
• Large shunt fraction or dependent-lung atelectasis

Preparation

• Discuss operation, anticipated OLV duration, need for CPAP or intermittent two-lung ventilation, risk of major haemorrhage, and postoperative destination.
• Large-bore IV access; arterial line for major resections, pneumonectomy, significant cardiopulmonary disease, or expected blood loss.
• Blood available for major resections/decortication.
• Thoracic epidural, paravertebral block, erector spinae plane block, or surgeon-performed intercostal blocks according to operation and contraindications.
• Avoid routine sedative premedication in severe respiratory disease.

3. Lung Isolation

Device choice

DLT safety steps

1. Insert in supine position.
2. Confirm with flexible bronchoscopy.
3. Reconfirm after lateral positioning, after surgical manipulation, and whenever oxygenation or airway pressures change.
4. Maintain minimal effective bronchial cuff pressure.
5. Ensure a patent suction channel and facilitate lung deflation before pleural opening.

4. Standard OLV Ventilation Strategy

Initial settings

• FiO2: 1.0 at initiation of OLV, then reduce only if oxygenation is stable and clinically appropriate.
• Tidal volume: 4-6 mL/kg ideal body weight.
• PEEP: Begin about 5 cmH2O, then individualise.
• Respiratory rate: Adjust for pH/PaCO2. Mild permissive hypercapnia is often acceptable if haemodynamically tolerated.
• I:E: Allow adequate expiratory time, particularly in COPD.
• Plateau pressure: Aim <25-30 cmH2O.
• Driving pressure: Keep as low as practical. PEEP titration guided by compliance and driving pressure is reasonable.
• Recruitment manoeuvre of the dependent lung after positioning and after disconnection/reconnection, followed by individually titrated PEEP.

PEEP principle

Haemodynamics

• Maintain adequate MAP, preload, RV perfusion, and cardiac output.
• Avoid both fluid overload and reflexive under-resuscitation.
• Treat clinically relevant hypotension with small fluid challenges only when indicated and use vasopressors early where appropriate.
• Excessive inotropy can raise pulmonary blood flow and shunt; low cardiac output lowers mixed venous saturation and can markedly worsen arterial oxygenation.

5. Hypoxaemia During OLV: Immediate Algorithm

First: call for help and communicate with surgeon

• Inform surgeon immediately.
• Ask whether the operative field permits temporary reinflation, CPAP, or intermittent two-lung ventilation.
• If severe/refractory hypoxaemia: resume two-lung ventilation immediately.

Stepwise checklist

A. Ensure oxygen delivery

1. Set FiO2 1.0.
2. Check circuit, oxygen supply, ventilator, flowmeters, sampling line, and pulse oximeter waveform.
3. Manually ventilate if uncertain about mechanics or equipment.

B. Exclude DLT/blocker malposition or obstruction

1. Flexible bronchoscopy is the priority.
   • DLT displaced proximally or distally?
   • Bronchial cuff herniation?
   • Right upper-lobe obstruction by a right DLT?
   • Blood, secretions, mucus plug, tumour obstruction?
   • Kinked lumen or blocker migration?
2. Suction both lumens and correct tube/blocker position.

C. Optimise the dependent, ventilated lung

1. Check for:
   • Low tidal volume/minute ventilation
   • Dependent-lung atelectasis
   • Excessive PEEP or auto-PEEP
   • Bronchospasm
   • Pneumothorax of the dependent lung
   • Endobronchial secretions
2. Perform dependent-lung recruitment if appropriate.
3. Titrate PEEP using compliance, plateau pressure, driving pressure, and oxygenation.
4. Treat bronchospasm and clear secretions.
5. Avoid excessive tidal volume and high airway pressure.

D. Optimise perfusion and oxygen carrying capacity

1. Correct significant hypotension, low cardiac output, severe anaemia, arrhythmia, or major blood loss.
2. Maintain normothermia.
3. Avoid unnecessary pulmonary vasodilators and high concentrations of volatile anaesthetic.

E. Improve oxygenation from the operative lung

1. If surgery permits, apply CPAP 1-5 cmH2O with oxygen to the non-dependent lung.
   • Start low because higher CPAP can impair exposure.
   • In VATS, CPAP may significantly interfere with the field and is generally a later manoeuvre.
2. Consider apnoeic oxygen insufflation to the operative lung in selected cases.
3. Intermittent two-lung ventilation is appropriate if hypoxaemia is persistent or severe.

F. Rescue

1. Request temporary surgical pause and reinflation of the operative lung.
2. Convert surgical approach if necessary.
3. If oxygenation remains unacceptable, abandon OLV until the cause is corrected.

6. VATS Anaesthetic Management

Key differences from open thoracotomy

• Usually requires reliable lung isolation and complete operative-lung collapse.
• VATS port insertion occurs before the lung may be fully collapsed. During this phase, shunt can increase and desaturation may occur.
• Limited direct access to the patient after positioning and draping.
• High risk events: pulmonary artery injury, major haemorrhage, sudden conversion to thoracotomy, capnothorax-related hypotension/arrhythmia when CO2 insufflation is used.

VATS plan

• Standard monitoring plus arterial line for major resections/high-risk patients.
• Left DLT in most cases; bronchoscopy after positioning.
• Protective OLV, judicious fluids, temperature management.
• Have a clear conversion plan:
  • Access to patient’s airway
  • Unobstructed side for emergency thoracotomy
  • Rapid infusion/blood availability
  • Team briefing for massive haemorrhage
• Multimodal analgesia: paravertebral/ESP block or intercostal blocks plus regular non-opioids if appropriate.
• Encourage early extubation, mobilisation, chest physiotherapy, and nausea prophylaxis.

7. Pneumonectomy Management

Intraoperative

• Arterial line and large-bore access.
• Consider central access when vasoactive support, complex fluid management, or major blood loss is anticipated.
• Careful OLV: protect the future single remaining lung.
• Avoid fluid excess. Use haemodynamic assessment and vasopressors rather than indiscriminate fluid administration.
• Prevent hypoxaemia, hypercapnia, acidosis, hypothermia, and high airway pressures, all of which may increase pulmonary vascular resistance and RV load.
• Expect haemodynamic changes when the pulmonary artery is clamped and after lung removal.

Postoperative priorities

• Extubate early when feasible. Avoid prolonged positive-pressure ventilation.
• ICU/HDU monitoring for major comorbidity, right pneumonectomy, borderline physiology, significant blood loss, or intraoperative instability.
• Effective regional/multimodal analgesia to allow cough and mobilisation.
• Manage atrial fibrillation, ischaemia, RV failure, and hypoxaemia promptly.
• Chest radiograph on arrival in PACU/ICU to assess mediastinal position.

Postpneumonectomy chest drain warning

• Do not apply routine suction to an empty postpneumonectomy space.
• A standard underwater seal or suction can cause mediastinal shift and haemodynamic collapse.
• Drain management must follow the thoracic surgeon’s specified plan, often using no drain, a balanced system, or temporary controlled aspiration.

Postpneumonectomy pulmonary oedema / acute lung injury

• Restrictive, individualised fluid strategy
• Avoid excessive transfusion where possible
• Protective ventilation
• Avoid high airway pressures and unnecessary hyperoxia
• Early recognition of RV dysfunction and pulmonary hypertension

• ICU care
• Exclude cardiogenic oedema, aspiration, pneumonia, pulmonary embolism, transfusion-related lung injury, and bronchopleural fistula
• Conservative fluid strategy and gentle diuresis if volume overloaded
• Lung-protective ventilation if intubation is unavoidable
• Early senior thoracic, ICU, and cardiology input where RV failure is present

8. Pleural Decortication Management

Major anaesthetic issues

• Sepsis, malnutrition, anaemia, chronic infection, restrictive physiology, hypoxaemia.
• Dense pleural adhesions make lung collapse incomplete and surgical dissection prolonged.
• Bleeding can be substantial due to inflamed pleura/chest wall adhesions.
• Air leaks and visceral pleural injury are common.
• Re-expansion pulmonary oedema is a concern when a chronically collapsed lung is re-expanded.
• Severe postoperative pain impairs cough and secretion clearance.

Management plan

• Correct dehydration, electrolyte disorders, coagulopathy, and anaemia where possible.
• Culture-directed antimicrobial therapy for empyema.
• Assess sepsis, respiratory reserve, and contralateral lung.
• Plan blood availability and postoperative critical-care level.

• DLT usually preferred for suction, isolation, and intermittent reinflation.
• Arterial line and blood products for extensive decortication.
• Protective dependent-lung ventilation.
• Anticipate difficult exposure, incomplete deflation, sudden bleeding, air leaks, and conversion from VATS to thoracotomy.
• Avoid excessive fluids while maintaining perfusion.
• Re-expand the released lung gradually, with surgeon communication, and avoid aggressive high-pressure recruitment.

• Extubate if gas exchange, haemostasis, and temperature allow.
• Monitor for bleeding, persistent air leak, bronchopleural fistula, sepsis, recurrent collection, and re-expansion pulmonary oedema.
• Regional analgesia, humidification, chest physiotherapy, early mobilisation, and lung expansion measures.
• Chest drain strategy is surgical-pathology specific. Unlike pneumonectomy, decortication commonly requires drains, often with suction initially if the surgeon requests it.

9. Postoperative Thoracic Anaesthesia Bundle

• Multimodal analgesia plus regional technique when appropriate.
• Avoid oversedation and excessive opioids.
• Incentive spirometry or coached deep breathing where used locally.
• Cough support, chest physiotherapy, early mobilisation.
• VTE prophylaxis.
• Treat nausea so the patient can mobilise and cough.
• Watch for: atelectasis, pneumonia, air leak, bronchopleural fistula, bleeding, atrial fibrillation, pulmonary embolism, respiratory failure, and post-resection lung injury.

One-line exam summary

Bariatric Surgery: Anaesthetic Management - 10-Mark Answer

1. Preoperative assessment and optimisation

• Assess BMI, functional capacity, hypertension, diabetes, ischaemic heart disease, heart failure, pulmonary hypertension, GERD, fatty liver, and difficult IV access.
• Screen for obstructive sleep apnoea (OSA) using STOP-BANG; establish home CPAP/BiPAP use and arrange postoperative use.
• Evaluate airway: large neck circumference, reduced neck movement, limited mouth opening, high Mallampati grade, prior difficult airway.
• Check Hb, glucose/HbA1c, electrolytes, renal function, ECG, and further cardiopulmonary investigations when indicated.
• Continue CPAP where prescribed; optimise diabetes and blood pressure. Plan postoperative destination early if severe OSA, obesity hypoventilation, poor room-air saturation, or major cardiorespiratory disease.

2. Equipment, transfer, positioning, and monitoring

• Confirm the operating table, transfer equipment, BP cuff, positioning aids, and bed are rated for the patient's weight.
• Use adequate staff and safe manual-handling equipment. A Hercules bariatric operating table is a high-capacity table designed for bariatric patients and permits safe articulation/positioning. It should be checked before transfer, including safe limits in the reverse-Trendelenburg position.
• Ramp the patient using a ramp or head-elevated laryngoscopy position (HELP), aligning the external auditory meatus with the sternal notch.
• Preoxygenate at ≥30° head-up. High-flow nasal oxygen or nasal cannula oxygen during apnoea can extend safe apnoea time.
• Standard monitoring; use arterial pressure monitoring selectively in severe obesity, pulmonary hypertension, major cardiovascular disease, difficult non-invasive BP monitoring, or anticipated prolonged/complex surgery.
• Apply forced-air warming, protect pressure areas, secure arms, and repeatedly check positioning after reverse Trendelenburg.

3. Airway and induction

• General anaesthesia with a cuffed tracheal tube is standard.
• Prepare for difficult mask ventilation and difficult intubation: videolaryngoscope, bougie/stylet, supraglottic airway, flexible bronchoscope, difficult-airway trolley, and a clear failed-airway plan.
• Preoxygenate thoroughly in the ramped, head-up position. Consider CPAP/NIV during preoxygenation in severe OSA or marked hypoxaemia.
• Use modified rapid-sequence induction when aspiration risk is increased, for example symptomatic reflux, diabetic gastroparesis, obstruction, or inadequate fasting.
• Avoid prolonged apnoea. Confirm tube position with capnography and secure the tube carefully, as reverse Trendelenburg and surgical manipulation may cause migration.

4. Drug dosing

• Propofol induction: commonly lean body weight or adjusted body weight, titrated to effect.
• Opioids and sedatives: ideal or adjusted body weight, with titration and caution because of OSA/hypoventilation.
• Rocuronium: commonly ideal body weight based, depending on institutional practice.
• Succinylcholine: generally total body weight based.
• Sugammadex: dose according to the depth of block and local protocol; ensure full reversal with quantitative monitoring.
• Avoid routine long-acting sedatives and minimise systemic opioids.

5. Ventilation during laparoscopy

• Pneumoperitoneum, Trendelenburg positioning, reduced FRC, and reduced chest-wall compliance promote atelectasis, raised airway pressure, hypercapnia, and hypoxaemia.
• Use lung-protective ventilation:
  • Tidal volume 6-8 mL/kg ideal body weight
  • Individualised PEEP, commonly 8-12 cmH2O initially
  • Recruitment manoeuvres when appropriate, followed by adequate PEEP
  • Adjust respiratory rate to control CO2
  • Maintain plateau/driving pressures as low as practicable
• Reverse Trendelenburg improves diaphragmatic movement, FRC, oxygenation, and surgical exposure.
• Watch for haemodynamic impairment from pneumoperitoneum and high PEEP.

6. Fluids, metabolic care, and VTE prevention

• Use balanced crystalloid with a goal-directed, restrictive-but-adequate strategy. Avoid fluid overload, which worsens pulmonary mechanics.
• Treat hypotension with vasopressors when appropriate rather than repeated large fluid boluses.
• Monitor glucose regularly in diabetes; avoid both hypoglycaemia and marked hyperglycaemia.
• Use mechanical VTE prophylaxis, pharmacological prophylaxis according to local protocol and bleeding risk, early mobilisation, and adequate hydration.

7. Analgesia and PONV prevention

• Use multimodal, opioid-sparing analgesia:
  • Paracetamol
  • NSAID/COX-2 inhibitor if appropriate and accepted by the bariatric surgeon
  • Local anaesthetic port-site infiltration
  • TAP block or other abdominal wall block where indicated
  • Low-dose ketamine, dexmedetomidine, or lidocaine infusion in selected patients
• Give multimodal PONV prophylaxis, commonly dexamethasone plus a 5-HT3 antagonist, with additional agents for high-risk patients.
• Minimise opioids because they increase postoperative airway obstruction and hypoventilation in OSA.

8. Emergence and extubation

• Extubate only when fully awake, warm, haemodynamically stable, and breathing adequately.
• Position head-up or semi-sitting.
• Preoxygenate before extubation.
• Confirm complete neuromuscular recovery using quantitative monitoring, ideally TOF ratio ≥0.9.
• Have a reintubation plan, with airway equipment immediately available.
• Restart CPAP/BiPAP early in patients who use it at home or who develop obstruction/hypoxaemia.

9. Postoperative care

• Observe carefully for airway obstruction, hypoventilation, hypercapnia, desaturation, aspiration, bleeding, anastomotic/staple-line leak, tachycardia, and VTE.
• Head-up nursing, early mobilisation, incentive breathing/physiotherapy according to local practice, and opioid minimisation.
• PACU monitoring should include continuous pulse oximetry. Consider HDU/ICU when there is severe OSA/obesity hypoventilation, persistent oxygen requirement, difficult airway, opioid need, or significant cardiopulmonary disease.

10. Tube management: Hercules/calibration tube and Ryle's tube

Gastric calibration tube/bougie

• Usually passed orally by the anaesthetist after induction, on the surgeon’s instruction.
• It calibrates the gastric sleeve and guides the staple line, often in the 32-40 Fr range.
• It may also permit gastric decompression and, depending on the device, leak testing.
• Maintain continuous communication:
  • Advance only to the requested depth.
  • Do not force against resistance.
  • The surgeon should confirm position laparoscopically when needed.
  • Withdraw it completely from the stapling field before firing staplers, as requested by the surgeon.
  • Never leave any tube across a staple line unintentionally.

Ryle's tube / nasogastric tube placement

1. Confirm indication and surgeon agreement.
2. Avoid nasal placement in facial/base-of-skull trauma; use an oral route if needed.
3. Lubricate, insert gently through the most patent nostril or mouth.
4. Advance without force. Stop if persistent resistance, coiling, bleeding, cough, desaturation, or haemodynamic instability occurs.
5. In an intubated patient, direct laryngoscopy or video-laryngoscopy can help prevent pharyngeal coiling. Intraoperative placement may be performed under direct laparoscopic/endoscopic guidance.
6. Confirm gastric position by an accepted institutional method. pH testing of aspirate and radiography are preferred confirmation methods. Do not rely on epigastric air insufflation alone.
7. Secure, document external length, function, and confirmation method.

• Do not insert a Ryle's/NG tube blindly.
• Altered anatomy, a small gastric pouch/sleeve, fresh staple lines, and anastomoses create a risk of perforation, staple-line disruption, or false passage.
• If decompression is essential, it must be discussed with the bariatric surgeon and ideally performed under direct endoscopic, fluoroscopic, or surgical guidance.

Anaesthetic Management of a Patient with Hepatic Encephalopathy and Choledocholithiasis

1. Preoperative assessment and optimisation

• Assess the severity and cause of encephalopathy: grade of consciousness, asterixis, agitation, ability to protect airway, history of prior episodes, and baseline cognition.
• Determine the severity of liver disease: Child-Pugh class, MELD score, jaundice, ascites, varices, spontaneous bacterial peritonitis, hepatorenal syndrome, coagulopathy, thrombocytopenia, malnutrition, and sarcopenia.
• Look actively for precipitants:
  • Cholangitis or other sepsis: fever, hypotension, leucocytosis, blood cultures
  • GI bleeding
  • Constipation
  • Dehydration or over-diuresis
  • Hypokalaemia, hyponatraemia, alkalosis
  • Renal dysfunction
  • Sedatives, alcohol, opioids, benzodiazepines
• Investigations: CBC and platelets, LFTs including bilirubin and albumin, PT/INR, fibrinogen, U&E, creatinine, glucose, ABG/VBG with lactate, ECG, group and cross-match. Blood cultures and imaging are indicated if cholangitis is suspected.
• Optimise before anaesthesia:
  • Lactulose, with rifaximin when indicated, and correction of the precipitating cause under hepatology/gastroenterology guidance.
  • Broad-spectrum antibiotics and urgent biliary drainage for cholangitis.
  • Correct hypoglycaemia, significant potassium/magnesium abnormalities, dehydration, and acid-base disturbance.
  • Avoid routine correction of INR solely because it is prolonged. Instead, assess bleeding history, platelet count, fibrinogen, procedure risk, and use viscoelastic testing where available.
  • Avoid unnecessary sedatives and benzodiazepines because they may worsen encephalopathy.

2. Anaesthetic planning

• Discuss jointly with the endoscopist, surgeon, gastroenterologist/hepatologist, and ICU team.
• The likely initial intervention is ERCP with sphincterotomy and stone extraction or stenting. ERCP is the usual therapeutic intervention to relieve common bile duct obstruction; definitive cholecystectomy may follow once the patient is stabilised. Fischer’s Mastery of Surgery, 8e, chapter on Choledocholithiasis.
• If the patient has grade III-IV encephalopathy, active vomiting, severe sepsis, haemodynamic instability, ascites impairing ventilation, or impaired airway reflexes, manage in a high-dependency/ICU environment and secure the airway with general anaesthesia and tracheal intubation.
• Deep sedation without a protected airway is unsuitable in a drowsy, uncooperative, or aspiration-risk patient.

3. Monitoring and access

• Standard monitoring: ECG, NIBP, SpO2, capnography, temperature, and neuromuscular monitoring if paralysis is used.
• Insert two reliable IV lines. Use ultrasound guidance if necessary.
• Consider an arterial line for severe liver dysfunction, septic shock/cholangitis, major electrolyte disturbance, significant bleeding risk, expected prolonged intervention, or vasopressor requirement.
• Cross-matched blood and blood products should be available if sphincterotomy-related bleeding is anticipated.
• Strict fluid balance and urine output monitoring are important, especially with ascites or renal dysfunction.

4. Airway and aspiration prophylaxis

• Encephalopathy, delayed gastric emptying, ascites, reflux, and emergency biliary sepsis increase aspiration risk.
• Use head-up preoxygenation. Prepare suction, videolaryngoscope, bougie, and a difficult-airway plan.
• Perform rapid-sequence induction when aspiration risk is high.
• A cuffed tracheal tube is preferred for urgent ERCP in an encephalopathic patient, especially as ERCP is often performed prone or semi-prone, making airway access limited.
• Avoid nasogastric tube insertion unless clinically necessary. If required after altered upper GI anatomy or in a high-risk situation, discuss with the procedural team and use appropriate guidance.

5. Choice of anaesthetic drugs

• Induction: propofol, titrated slowly to effect, is commonly suitable because of rapid redistribution and recovery.
• Opioid: fentanyl in small titrated doses or remifentanil infusion. Avoid large doses and long-acting opioids.
• Muscle relaxant: cisatracurium or atracurium are preferred because organ-independent Hofmann degradation/ester hydrolysis reduces reliance on hepatic metabolism.
• Maintenance: low-dose volatile agent or propofol-based TIVA, titrated carefully. Avoid excessive depth of anaesthesia and hypotension.
• Avoid or minimise: benzodiazepines, long-acting opioids, and drugs with prolonged hepatic metabolism.
• Give antiemetic prophylaxis, such as ondansetron with or without dexamethasone if clinically appropriate.

6. Intraoperative goals

• Maintain adequate hepatic and renal perfusion: avoid hypoxaemia, hypercapnia, hypothermia, severe anaemia, and prolonged hypotension.
• Treat hypotension early with cautious balanced crystalloid and vasopressors, commonly norepinephrine when vasodilatory shock is present, rather than indiscriminate large-volume fluid administration.
• Avoid fluid overload because ascites, cirrhotic cardiomyopathy, and low albumin predispose to pulmonary oedema.
• Maintain normoglycaemia. Monitor glucose regularly, as hepatic glycogen stores may be limited.
• Correct significant electrolyte abnormalities, particularly potassium and magnesium.
• Use low tidal-volume ventilation with adequate PEEP, while avoiding excessive intrathoracic pressure that can impair venous return and hepatic blood flow.
• Maintain normothermia and monitor for bleeding after sphincterotomy.

7. Coagulation management

• Cirrhosis produces a rebalanced but fragile haemostatic state: both bleeding and thrombosis are possible.
• Check platelet count, fibrinogen, PT/INR, and ideally TEG/ROTEM where available.
• Correct clinically significant abnormalities selectively, particularly if therapeutic ERCP with sphincterotomy is planned or active bleeding occurs.
• Give platelets, fibrinogen replacement, plasma, or PCC only according to clinical bleeding risk, procedural need, local policy, and specialist advice, not simply to normalise an INR.

8. Procedure-specific issues in ERCP

• ERCP enables sphincterotomy, stone extraction, biliary drainage, and stent placement. It is primarily therapeutic rather than diagnostic in modern practice, as MRCP/EUS can define duct pathology non-invasively. See the ERCP overview.
• Anticipate and monitor for:
  • Aspiration
  • Hypoxaemia, hypoventilation, and airway difficulty in prone positioning
  • Hypotension from sepsis, anaesthetic drugs, or dehydration
  • Sphincterotomy bleeding
  • Post-ERCP pancreatitis
  • Perforation, cholangitis, and basket/stent complications
• If severe cholangitis is present, source control by biliary drainage should not be delayed unnecessarily for full correction of all biochemical abnormalities.

9. Emergence and postoperative management

• Extubate only when the patient is awake enough to protect the airway, with stable cardiorespiratory status, acceptable gas exchange, complete reversal of neuromuscular block, and improving encephalopathy.
• Elective postoperative ventilation and ICU admission are appropriate for severe encephalopathy, sepsis, shock, significant ascites, ongoing encephalopathy, renal failure, or high oxygen/vasopressor requirement.
• Continue lactulose/rifaximin as advised, antibiotics for cholangitis, careful electrolyte replacement, glucose monitoring, and avoidance of sedating drugs.
• Monitor serial mental state, GCS, respiratory rate, SpO2, urine output, creatinine, electrolytes, bilirubin, INR, lactate, and evidence of post-ERCP complications.
• Use opioid-sparing analgesia. Paracetamol may be used in reduced total daily dose according to local liver-disease policy; avoid NSAIDs in significant cirrhosis, renal impairment, ascites, or bleeding risk.

Conclusion