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Physiology of laparoscopy and robotic surgery
Insufflating the abdomen with CO2 at 12–15 mmHg raises systemic resistance, reduces venous return and lung volumes, and is absorbed into the blood — so ventilation is increased, bradycardia on insufflation is watched for, and complications of gas in the wrong places are sought.
Why it matters in the exam
The exam asks what happens to blood pressure, cardiac output and heart rate during insufflation, why EtCO2 rises and what to do, what causes desaturation and rising airway pressure (endobronchial intubation as the diaphragm pushes the lungs up, CO2 pneumothorax), and the signs of CO2 embolism and subcutaneous emphysema. It also asks about the problems of steep Trendelenburg in robotic surgery.
At the start of insufflation peritoneal stretch may cause sudden vagal bradycardia and even asystole — the pressure is released and atropine given. Abdominal pressure raises systemic resistance and blood pressure, but in a hypovolaemic patient cardiac output falls. The diaphragm rises, FRC and compliance fall, and the carina moves upward — a tube that was in place may enter the right main bronchus. CO2 is absorbed, so minute ventilation is increased.
In steep Trendelenburg for robotic surgery there is facial and airway oedema, a rise in intraocular and intracranial pressure, and a danger of sliding and brachial plexus injury — so a cuff leak around the tube is checked before extubation. After surgery shoulder-tip pain comes from irritation of the diaphragm by residual gas. Laparoscopy has clear advantages: less pain, fewer lung complications and faster recovery. In a patient with poor cardiac function or pulmonary hypertension the abdomen is insufflated at the lowest workable pressure and volume is adjusted.
Key points
- Insufflation with CO2 at 12–15 mmHg.
- Resistance rises, venous return falls, vagal bradycardia on insufflation.
- FRC falls; the tube may migrate into a bronchus.
- CO2 is absorbed — increase ventilation.
- Complications: CO2 embolism, emphysema, pneumothorax; Trendelenburg — airway oedema.
Summary table
| System | Change | What is done |
|---|---|---|
| Heart and vessels | Resistance and blood pressure rise; output falls with hypovolaemia; bradycardia on insufflation | Adequate volume; stop insufflation and atropine for bradycardia |
| Breathing | FRC and compliance fall; pressures rise; the tube may migrate into a bronchus | PEEP, check tube position |
| CO2 | Absorption and a rise in EtCO2 | Increase minute ventilation |
| CO2 embolism | Sudden hypotension, abrupt change in EtCO2, a murmur | Stop insufflation, release gas, left side and head down, 100% oxygen |
| Emphysema / CO2 pneumothorax | Crepitus; rising pressures and falling saturation | Stop or lower pressure; usually absorbs by itself |
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Sources
- Miller's Anesthesia, 9th edition (2020) — Anesthesia for Laparoscopic and Robotic Surgeries
- Morgan & Mikhail's Clinical Anesthesiology, 7th edition (2022) — Anesthesia for Laparoscopic Surgery
Sources are given for further reading; the text is written afresh and not copied from them.
Reviewed by the Examqo AI Professor · 2026-11-02. The text may contain errors; when in doubt, check the source.