Carboxyhaemoglobin formation and ECG changes during hysteroscopic surgery, transurethral prostatectomy and tonsillectomy using bipolar diathermy

Prospective Study Investigating Change in Carboxyhemoglobin Blood Level During Operative Hysteroscopy

STUDY OBJECTIVES

To evaluate whether the use of radiofrequency energy during resectoscopy leads to increases in patient blood levels of carboxyhemoglobin (COHb) and investigate procedural variables associated with these elevations.

DESIGN

A prospective cross-sectional study of 40 subjects undergoing a hysteroscopic procedure using bipolar radiofrequency energy.

SETTING, PATIENTS, AND INTERVENTIONS

The study was conducted at an ambulatory surgery center. Procedures for uterine leiomyoma, septa, products of conception, or a combination of these pathologies were included. We measured blood COHb levels before and immediately after the surgery. Abnormal postoperative COHb level was defined as an increase of plasma COHb ≥3.0%. All patients with abnormal postoperative levels were contacted and screened for carbon monoxide toxicity symptoms. Summary statistics included frequency for categorical variables and averages for continuous variables. p values were reported without modification.

MEASUREMENTS AND MAIN RESULTS

A total of 17.5% of subjects met the criteria for abnormal postoperative COHb levels. None of these subjects reported symptoms of carbon monoxide toxicity. One subject with an elevated postoperative COHb level had intraoperative hemodynamic changes possibly related to COHb elevation. An abnormal postoperative COHb level was associated with a higher fluid deficit (p = .024) and greater myoma volume (p = .04).

CONCLUSION

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 myoma volume. Although none of the subjects with an abnormal increase screened positive for symptoms in the postoperative setting and only 1 experienced hemodynamic changes intraoperatively, 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 hysteroscopic resections.

Carbon Monoxide poisoning and Air Embolism following Hysteroscopic Myomectomy: a case report

INTRODUCTION

Uterine myomas are the most common benign uterine tumors. Hysteroscopic myomectomy has grown as a standard minimally invasive surgical procedure, but this technique is not free from complications.

CASE

An hysteroscopic myomectomy was performed on a 38 years-old woman. During the awakening after the procedure, she presented focal neurological deficits, thus arterial blood gas test and total body computerized tomography (CT) scan were urgently carried out. They revealed a very high carboxyhemoglobin level and abdominal venous air embolism. The patient stayed in Trendelenburg position and under mechanical ventilation with 100% oxygen concentration. Fortunately, a few hours later she was fully awake and was able to be successfully extubated, being discharged to the surgical ward three days later fully recovered.

CONCLUSION

Carbon monoxide poisoning during hysteroscopic resection is a rare but potentially fatal complication that anesthetists, gynecologists, and critical care physicians should be aware of.

Hysteroscopic myomectomy: The guidelines of the International Society for Gynecologic Endoscopy (ISGE)

OBJECTIVE

With this publication, the International Society for Gynecologic Endoscopy (ISGE) aims to provide the clinicians with the recommendations arising from the best evidence currently available on hysteroscopic myomectomy (HM).

STUDY DESIGN

The ISGE Task Force for HM defined key clinical questions, which led the search of Medline/PubMed and the Cochrane Database. We selected and analyzed relevant English-language articles, published from January 2005 to June 2021, including original works, reviews and the guidelines previously published by the European Society for Gynecological Endoscopy (ESGE) and the American Association of Gynecologic Laparoscopists (AAGL), in which bibliographies were also checked in order to identify additional references, using the medical subject heading (MeSH) term "Uterine Myomectomy" (MeSH Unique ID: D063186) in combination with ''Myoma" (MeSH Unique ID: D009214) and ''Hysteroscopy" (MeSH Unique ID: D015907). We developed the recommendations through multiple cycles of literature analysis and expert discussion.

RESULTS

The ISGE Task Force did develop 10 grade 1A-C and 4 grade 2A-C recommendations. For planning HM, evaluation of the uterus with saline infusion sonohysterography (SIS) or combined assessment by transvaginal ultrasound (TVUS) and diagnostic hysteroscopy is recommended (Grade 1A). The use of STEPW (Size, Topography, Extension of the base, Penetration and lateral Wall position) classification system of submucosal leiomyoma (LM) is recommended to predict the complex surgeries, incomplete removal of the LM, long operative time, fluid overload and other major complications (grade 1B). For type 0 LMs, in addition to resectoscopy (slicing technique), morcellation is recommended, being faster and having a shorter learning curve with respect to resectoscopy (grade 1C). For type 1-2 LMs, slicing technique is currently recommended (grade 1C). A fluid deficit of 1000 mL also in case of bipolar myomectomy with saline solution, in healthy women of reproductive age, contains low risk for major complications. Lower thresholds (750 mL) for fluid deficit should be considered in the elderly and in women with cardiovascular, renal or other co-morbidities (Grade 1B).

CONCLUSION

HM is the most effective conservative minimally invasive gynecologic intervention for submucous LM. The set of 14 ISGE recommendations can significantly contribute to the success of HM and the safety of patients for whom the choice of appropriate surgical technique, as well as the surgeon's awareness and measures to prevent complications are of the utmost importance.

Comparing volumetric and biochemical assessment of intravasation caused by hysteroscopic surgery

BACKGROUND

During hysteroscopic surgery intravasation of irrigation fluid occurs, leading to potentially dangerous intravascular fluid overload. Currently, intravasation is usually measured volumetrically as fluid deficit. Intravasation could also be calculated using the decrease in hemoglobin or increase in chloride ion concentration, both phenomena known to result from intravasation. We compared the values of intravasation measured volumetrically as fluid deficit versus calculated from the biochemical change in hemoglobin and chloride. We expected that these values would show strong correlation and agreement.

METHODS

In a retrospective data analysis of 51 patients who underwent hysteroscopic resection of myomas or endometrium a pre and post procedure concentration of haemoglobin and chloride was available. The fluid deficit was plotted against the two versions of calculated intravasation. Furthermore, we put the data into Bland-Altman plots to scrutinize their relationship.

RESULTS

The volumetric assessed fluid deficit and both versions of biochemically assessed intravasation, either using the change in hemoglobin or chloride ion concentration, turned out to be three totally different entities with weak correlation. Bland-Altman plots show too wide limits of agreement, and a striking difference between the two methods of calculated intravasation.

CONCLUSION

Our study shows significant differences and poor agreement between volumetric and biochemically assessed intravasation. Based on this study, routinely assessing intravasation by biochemical methods does not have additional benefit compared to the volumetric fluid deficit. It remains unclear which method resembles true intravasation.