Sidestream capnographic monitoring reduces the incidence of arterial oxygen desaturation during propofol ambulatory anesthesia for surgical abortion

Abstract

Background: This study investigated whether early intervention based on additional use of sidestream capnography could reduce the incidence of oxygen desaturation and hypoxic events in patients receiving propofol anesthesia during surgical abortion.

Material/methods: We recruited 704 ASAI-III female patients, 18-52 years old and scheduled for planned painless surgical abortion, and randomized them into a control group (n=359) receiving standard monitoring and an experimental group (n=341) receiving standard monitoring and additional capnography. Exclusion criteria were preexisting cardiovascular disease, preexisting hypotension, bradycardia or arrhythmia, and drug allergy. Anesthesia was induced in all patients with propofol using target-controlled infusion at a target propofol plasma concentration of 4 μg/ml. All patients received flurbiprofen axetil 50 mg and 0.5 μg/kg fentanyl 5 min before anesthesia. Bispectral index was used and maintained between 45 and 60. Main outcome measures were apnea or abnormal ventilation status, rate of oxygen desaturation, occurrence of hypoxia and severe hypoxia, and perioperative side effects.

Results: The experimental group had significantly higher rate of apnea or abnormal ventilation, significantly lower rate of oxygen desaturation, and significant lower occurrence of hypoxia and severe hypoxia compared to the control group. We found no statistically significant differences between the 2 groups in the rates of increased oxygen supplementation, assisted ventilation, bradycardia, hypotension, dosage of atropine, dosage of ephedrine or phenylephrine, and the amount of propofol consumed.

Conclusions: Sidestream capnographic monitoring improves early detection of alterations in ventilation parameters and reduces the incidence of oxygen desaturation and hypoxemia resulting from propofol anesthesia during surgical abortion.

Figure 1

Flow diagram shows enrolled and missed patients.