Pneumoperitoneum

1. Pneumoperitoneum
in Laparoscopic Surgery
Matt Wagaman CA1

2. Advantages of Laparoscopic Surgery
• Reduced postoperative pain
• Improved post operative mobilization 
return to activity quicker
• Small scar  less chance of hernia/cosmetic
• Reduced wound infections
• Reduced hospital stay
BUT…….

3. • Expansion of laparoscopic general surgery has shifted
patient demographics so that more elderly, debilitated
patients w/ significant comorbidities undergo laparoscopic
surgery.
– Report from 35 Connecticut hospitals, more than one third of
patients undergoing laparoscopic cholecystectomy were more
than 55 years of age, almost one quarter were more than 65
years of age, and 8% were more than 75 years of age. (Orlando
et al.)
• These patients are more susceptible to perioperative
complications due to the hemodynamic and cardio-
respiratory changes caused by pneumoperitoneum.
• Thus, it is important that anesthesiologists and surgeons
understand these potential complications so that
appropriate measures can be taken to ensure optimal
perioperative support.

4. Pneumoperitoneum
• Abdominal insufflation w/ CO2, helium, nitrous oxide, or
oxygen to ~ 15 mmHg
– Normal Intra-abdominal pressure (IAP) < 5 mmHg
• CO2 most commonly used gas.
– Noncombustible = safe to use with electrosurgical devices
– Solubility in blood and reactivity w/ soluble buffering systems
minimize the risk of gas emboli ( )
• Systemic absorption thought to be facilitated by CO2
specific widening of inter-cellular junctions in peritoneum
 buffering of CO2 as above  Systemic Acidification

5. Systemic acidification (pCO2 ~55) and increased
intraperitoneal pressure (>15 mmHg) can cause
cardiac arrhythmias, constriction of pulmonary
vasculature, and alterations in cardiac function

6. Cardiovascular Effects of ↑ IAP
• ↑ IAP  ↓ Venous Return  ↓ Preload 
↓CO  ↑ HR, MAP, SVR, and PVR
• These effects amplified by IAP > 15 mmHg and
reverse Trendelenberg positioning.
• Pneumoperitoneum can produce significant
hemodynamic stress. An awareness of potential
complications, especially in patients with
significant cardiac disease (i.e severe CAD) is
essential.

7. Respiratory Effects of ↑ IAP
Increased intra-abdominal pressure displaces the diaphragm cephalad
causing:
– ↑PIP  Consider pressure mode ventilation
– ↑ IP volume  Compression basilar lung segments  ↓
FRC  ↑ alveolar dead space  V/Q mismatch
– ↓ Vital Capacity
– ↓ FRC
– ↑ Intra-thoracic pressure  May worsen w/ Trendelenberg position and may
exacerbate GERD
• Protect airway in patients at risk of aspiration
Usually only clinically significant in patients w/ pre-existing
pulmonary comorbidities
– WATCH OUT if your patient has COPD w/ impaired compensatory mechanisms  High
risk of hypoxemia and significant hypercapnia!

8. Renal Effects of ↑ IAP
• Studies have shown 35-60% decrease in RBF with ↑ IAP during
pneumoperitneum
• ↓ RBF  ↑ ADH, plasma rennin activity, and serum aldosterone 
OLIGURIA
• Extent of oliguria directly related to ↑ IAP and studies have shown
improvement w/ desufflation
• Anticipate potential complications in patients w/ pre-existing renal
impairment especially if high IAP used.
• May need to ask surgeon use minimal insufflation pressure

9. Hepatic Effects of ↑ IAP
• Pneumoperitoneum decreases Hepatic blood flow in
manner similar to renal blood flow.
• Can lead to acute hepatocellular injury w/ transient
↑ LFT w/ normalization within 72h
• Decrease injury by keeping IAP < 15 mmHg,
minimizing traumatic liver retraction, and avoid
anesthetics that could worsen liver function.

10. Intraoperative Management
“Proper Prior Planning Prevents Poor
Performance”
Preoperative planning and vigilant intra-operative control of detrimental effects of
CO2 pneumoperitoneum are key to a safe and successful outcome!

11. Monitors
Based on the patient’s comorbidities ensure you have the ability
to adequately monitor how CO2 pneumoperitoneum and ↑
IAP are effecting your patient.
ASA standard monitors ±
– Foley
– Arterial line (Useful to monitor ABGs to detect arterial
and ETCO2 difference  changes to ventilation.)
– CVP (May be helpful in extreme cases where volume
status is a concern; otherwise unreliable and usually not
worth the risk)

12. Fluids Status
• After placing IV  Can counterbalance expected hemodynamic
effects of ↑ IAP w/ moderate fluid hydration (500cc-1L NS/LR vs.
Hespan)
• Fluid hydration w/ pneumoperitoneum:
– Preserves CO, SV, and RBF while increasing UOP.
– Improves hemodynamic function in all patient positions
– Avoid aggressive hydration in patients at risk of potential
complications of fluid overload (CHF, CRF, ICU patients)
Pre-operative hydration can be helpful to minimizing the negative
effects of pneumoperitoneum

13. Positioning
• Trendelenberg:
– Advantage: ↑ Venous return  Less hemodynamic stress
– Disadvantages:
• ↑ ITP  Decrease lung compliance
• Increased venous pressure and stasis in the head maybe cause falsly
decreased SpO2 reading and poor wave form.
• Debatable risk of ↑ ICP
• ↑ ICP from steep trendelenberg has been shown to cause choroidal
vasodilation  ↑ ICP and ↑ intraocular pressure  blindness. (Awad et
al)
• Reverse Trendelenberg:
– Advantage: Improved lung compliance
– Disadvantage: ↓ Venous return  HD stress and blood pooling ↑ DVT risk
Collaborate with the surgeon to place patient in the
position that is best for your patient’s needs

14. Ventilation
• Most patients tolerate mild increases in PaCO2
• Patient with high metabolic and cellular respiratory rates (septic
patients), impaired regional blood flow, large dead space (COPD),
or poor CO may have poor homeostatic reserve and be at risk for
developing more severe acidosis. (Safran)
• ↑ Minute Ventilation to prevent respiratory acidosis by ↑ RR
– Increasing RR and keeping TV low can minimize already ↑ PIP from ↑
ITP yet still eliminate increased CO2 from peritoneal absorption
– Adjust based on patient specific concerns i.e. COPD, volume status, or
obesity (risk of intrinsic PEEP)
• Use PEEP cautiously!
– PEEP will improve gas exchange BUT….
– PEEP will also ↑ ITP  ↓ CO
– Rarely beneficial at levels > 5 mmHg

15. Gas Embolism
• Extremely rare but has been reported during laparoscopy.
• Suspect if patient has acute cardiovascular collapse or
otherwise unexplained dysrrhythmia.
• Mill-wheel murmur may help make diagnosis of gas
embolism
– A temporary loud, machinery-like, churning or splashing sound
due to blood mixing with air in the right ventricle, best heard
over the precordium.
• If suspected place patient in left lateral decubitus position
and support hemodynamics/ventilation.

16. Abbreviations
• Abbreviations:
• IAP: Intra-abdominal pressure
• PIP: Peak inspiratory pressure
• IP: Intra-peritoneal
• RBF: Renal blood flow
• ITP: Intra-thoracic pressure
• ICP: Intra-cranial pressure
• HD: Hemodynamic

17. References
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128: 494-9.
• Puri GD, Singh H. Ventilatory effects of laparascopy under general anesthesia. BR J Anaesth 1992; 68: 211-3
• Safran DB, Orlando R. Physiologic effects of Pneumoperitoneum. 3rd Am J Surg. 1994 Feb; 167(2): 281-6.
• Alvarez A, Brodsky JB, Lemmons H, Morton JM. Morbid Obesity Perioperative Management, 2nd Ed. Cambridge
University Press, 2010
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exchange during carbon dioxide-pneumoperitoneum in a porcine model. Br J Anaesth. 2010 Nov;105(5):691-7.
Epub 2010 Aug 6.
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Koivusalo AM, Lacy A, McMahon MJ, Millat B, Schwenk W. The European Association for Endoscopic Surgery
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• Demyttenacre SV. Feldman I.S., Bergman S, et al. Does aggressive hydration reverse the effects of
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