7606 Prospective Study Investigating Change in Carboxyhemoglobin Blood Level during Operative Hysteroscopy

Abstract

<h3>Study Objective</h3> Evaluate whether the use of radiofrequency energy during operative hysteroscopy leads to increases in patient blood levels of carboxyhemoglobin and to investigate procedural variables associated with these elevations. <h3>Design</h3> A cross-sectional study of 40 patients undergoing a hysteroscopic procedure using bipolar radiofrequency energy. <h3>Setting</h3> Ambulatory surgery center <h3>Patients or Participants</h3> Procedures for uterine leiomyoma, septa, products of conception, or a combination of these pathologies were included. Blood carboxyhemoglobin (COHb) levels were measured prior to and after surgery. Abnormal post-op carboxyhemoglobin level was defined as an increase of plasma carboxyhemoglobin ≥ 3.0%. All patients with abnormal post-operative levels were contacted and screened for carbon monoxide toxicity symptoms. No additional follow-up was conducted. <h3>Interventions</h3> Operative hysteroscopy was performed per standard protocol and the COHb blood levels were measured as described above. No additional interventions occurred. <h3>Measurements and Main Results</h3> 17.5% of patients met the criteria for abnormal post-op COHb levels. None of these patients reported symptoms of carbon monoxide toxicity. One patient with an elevated post-op COHb level had intra-operative hemodynamic changes. Summary statistics included frequency for categorical variables and averages for continuous variables. An abnormal postop COHb level was associated with a higher fluid deficit (p-value 0.024) and greater fibroid volume (p-value 0.04). <h3>Conclusion</h3> This study demonstrates that systemic absorption of carbon monoxide is a reproducible phenomenon in hysteroscopic resections using bipolar diathermy. Greater absorption is associated with a higher fluid deficit and greater fibroid volume. Although none of the patients with an abnormal increase screened positive for symptoms in the post-op setting and only one experienced hemodynamic changes intra-operatively, our study looked at a healthy and young patient population. More research is needed on the safety of this COHb exposure in patients with medical comorbidities. Special consideration should be given to the possibility of carbon monoxide absorption and the uncertain long-term effects when planning extensive resections.