What occurs to CO2 flow and pressure if the Veress needle is not positioned inside the peritoneal cavity?

When the Veress needle is improperly positioned outside of the peritoneal cavity, CO2 flow is impacted significantly. In this scenario, the gas introduced through the needle cannot enter the abdominal cavity, leading to a reduction in the flow of CO2. Because the gas is unable to fill the peritoneal space, pressure within that area will increase as attempts to compress the gas and achieve insufflation will not meet with success. The pressures could rise above the intended range since the gas is not dispersing and is instead being forced into a closed space created by the needle itself.

In summary, when the Veress needle is not correctly placed inside the peritoneal cavity, this results in decreased gas flow and an increase in pressure due to the inability to achieve proper insufflation.