Effects of different fractions of inspired oxygen on gas embolization during hysteroscopic surgery: A double-blind, randomized, controlled trial

OBJECTIVE

Gas embolism is a common complication of hysteroscopic surgery that causes serious concern among gynecologists and anesthesiologists due to the potential risk to patients. The factors influencing gas embolism in hysteroscopic surgery have been extensively studied. However, the effect of the oxygen concentration inhaled by patients on gas embolism during hysteroscopic surgery remains elusive. Therefore, we designed a double-blind, randomized, controlled trial to determine whether different inhaled oxygen concentrations influence the occurrence of gas embolism during hysteroscopic surgery.

METHODS

This trial enrolled 162 adult patients undergoing elective hysteroscopic surgery who were randomly divided into three groups with inspired oxygen fractions of 30%, 50%, and 100%. Transthoracic echocardiography (four-chamber view) was used to evaluate whether gas embolism occurred. Before the start of surgery, the four-chamber view was continuously monitored.

RESULTS

The number of gas embolisms in the 30%, 50%, and 100% groups was 36 (69.2%), 30 (55.6%), and 24 (44.4%), respectively. The incidence of gas embolism gradually decreased with increasing inhaled oxygen concentration (P = 0.031).

CONCLUSION

In hysteroscopic surgery, a higher oxygen concentration inhaled by patients may reduce the incidence of gas embolism, indicating that a higher inhaled oxygen concentration, especially 100%, could be recommended for patients during hysteroscopic surgery.

TRIAL REGISTRATION

Chinese Clinical Trial Registry (https://www.chictr.org.cn/showproj.html?proj=53779, Registration number: ChiCTR2000033202).

Air Embolism: A Rare Lethal Complication of Hysteroscopy in a Young Woman Undergoing Infertility Workup

Compared to operative hysteroscopy, diagnostic hysteroscopy rarely leads to issues. However, one very uncommon yet potentially fatal complication is air embolism, with an incidence rate of three in 17,000 cases. This report describes an unexpected complication discovered during diagnostic hysteroscopy surgery. In the course of routine infertility testing, a 29-year-old woman underwent a diagnostic hysteroscopy under general anesthesia. Intraoperatively, her end-tidal carbon dioxide (EtCO2) levels decreased, oxygen saturation dropped, and heart rate increased, leading the anesthesiologists and critical care team to terminate the procedure and manage her further. Subsequent transesophageal echocardiography confirmed the diagnosis of air embolism. She was managed with 100% oxygen and inotropes and cardiopulmonary resuscitation but despite aggressive medical interventions, her condition did not improve, and she unfortunately passed away. To diagnose, prevent, and manage the potentially devastating consequences associated with diagnostic hysteroscopy, gynecologists and surgical teams must maintain vigilance. The focus should be on proper patient selection, optimal surgical techniques, and the use of high-quality equipment to mitigate the risk of air embolism.

Application of the C3 inhibitor compstatin in a human whole blood model designed for complement research - 20 years of experience and future perspectives

The complex molecular and cellular biological systems that maintain host homeostasis undergo continuous crosstalk. Complement, a component of innate immunity, is one such system. Initially regarded as a system to protect the host from infection, complement has more recently been shown to have numerous other functions, including involvement in embryonic development, tissue modeling, and repair. Furthermore, the complement system plays a major role in the pathophysiology of many diseases. Through interactions with other plasma cascades, including hemostasis, complement activation leads to the broad host-protective response known as thromboinflammation. Most complement research has been limited to reductionistic models of purified components and cells and their interactions in vitro. However, to study the pathophysiology of complement-driven diseases, including the interaction between the complement system and other inflammatory systems, holistic models demonstrating only minimal interference with complement activity are needed. Here we describe two such models; whole blood anticoagulated with either the thrombin inhibitor lepirudin or the fibrin polymerization peptide blocker GPRP, both of which retain complement activity and preserve the ability of complement to be mutually reactive with other inflammatory systems. For instance, to examine the relative roles of C3 and C5 in complement activation, it is possible to compare the effects of the C3 inhibitor compstatin effects to those of inhibitors of C5 and C5aR1. We also discuss how complement is activated by both pathogen-associated molecular patterns, inducing infectious inflammation caused by organisms such as Gram-negative and Gram-positive bacteria, and by sterile damage-associated molecular patterns, including cholesterol crystals and artificial materials used in clinical medicine. When C3 is inhibited, it is important to determine the mechanism by which inflammation is attenuated, i.e., whether the attenuation derives directly from C3 activation products or via downstream activation of C5, since the mechanism involved may determine the appropriate choice of inhibitor under various conditions. With some exceptions, most inflammatory responses are dependent on C5 and C5aR1; one exception is venous air embolism, in which air bubbles enter the blood circulation and trigger a mainly C3-dependent thromboembolism, with the formation of an active C3 convertase, without a corresponding C5 activation. Under such conditions, an inhibitor of C3 is needed to attenuate the inflammation. Our holistic blood models will be useful for further studies of the inhibition of any complement target, not just C3 or C5. The focus here will be on targeting the critical complement component, activation product, or receptor that is important for the pathophysiology in a variety of disease conditions.

Hysteroscopy and the risk of gas embolism: A review

Hysteroscopy is one of the most frequent procedures that a gynecologist will perform over their career. It is also one of the safest procedures. Operative hysteroscopy has an increased risk profile due to the nature of the surgery. The following review will address the issue of gas embolism in hysteroscopy. This review will look at the evidence regarding the likely causation, rates, and potential methods of minimizing risk to patients as well as treatment options available should this complication arise.

Gas Embolism During Hysteroscopic Surgery?: Three Cases and a Literature Review

During a period of 1 month, 3 episodes of probable or actual venous air embolism occurred during hysteroscopic surgery. All patients developed the same symptoms of ventilatory and hemodynamic decompensation, beginning with a reduction in end-tidal carbon dioxide, arterial desaturation, and cyanosis on the upper trunk, and rapidly progressed to hypotension and 2 cardiac arrests. While entrainment of some air is common during hysteroscopy, life-threatening embolism is a rare but serious complication for which an anesthetist needs to be vigilant and prepared. If even a small drop in end-tidal carbon dioxide occurs, venous air embolism should be suspected and the operation should be discontinued.

Monitoring of Gas Emboli During Hysteroscopic Surgery: A Prospective Study

OBJECTIVES

Previous studies have demonstrated a high frequency of gas emboli during hysteroscopy, but guidelines for the prevention, early detection, and intervention of gas embolism during hysteroscopic procedures are still lacking. This study aimed to gain a clearer understanding of risk factors and specific signs and symptoms associated with gas emboli.

METHODS

This prospective study enrolled 120 women scheduled for hysteroscopy using 5% glucose as distension medium. The gas bubbles were monitored sequentially in internal iliac vein, common iliac vein, inferior vena cava, superior vena cava, heart, and pulmonary artery under the gray-scale imaging of Doppler ultrasound. The frequency, extent, and the hemodynamic and respiratory effects of gas emboli were evaluated. The interventions and outcomes were recorded. The risk factors associated with gas emboli, and their relationship with the frequency and extent of gas emboli, were assessed.

RESULTS

In our study, evidence of gas emboli under Doppler ultrasound monitoring was observed in 44 (36.7%) patients. The operation was continued and finished as soon as possible for patients presenting with stable vital signs or transient hemodynamic and respiratory changes, which resolved spontaneously without intervention. The operation was paused for patients presenting with significant hemodynamic changes or loss of consciousness, and the operation was resumed shortly after resumption of stable vital signs following symptomatic treatment. All patients in our study finished the operation and recovered without developing serious complications. Data analysis showed prolonged procedure duration and increased bleeding volume were both positively correlated with the frequency and extent of gas emboli.

CONCLUSION

Our study demonstrated a high frequency of gas emboli during hysteroscopy. Doppler ultrasonic monitoring combined with a clearer understanding of specific signs, symptoms, and risk factors will facilitate early detection and intervention of gas emboli during hysteroscopy.

Complications of Hysteroscopic and Uterine Resectoscopic Surgery

Adverse events associated with hysteroscopic procedures are generally rare, but, with increasing operative complexity, it is now apparent that they are experienced more often. There exists a spectrum of complications that relate to generic components of procedures, such as patient positioning, anesthesia, and analgesia, to a number that are specific to intraluminal endoscopic surgery that largely comprise perforation and injuries to surrounding structures and blood vessels. Whereas a number of endoscopic procedures require the use of distending media, the response of premenopausal women to excessive absorption of nonionic fluids used for hysteroscopy is somewhat unique, and deserves special attention on the part the surgeon. There is also an increasing awareness of uncommon but problematic sequelae related to the use of monopolar radiofrequency uterine resectoscopes that involve thermal injury to the vulva and vagina. Furthermore, the uterus that has previously undergone hysteroscopic surgery may behave in unusual ways, at least in premenopausal women who experience menstruation or who become pregnant. Fortunately, better understanding of the mechanisms involved in these adverse events, as well as the use or development of a number of innovative devices, have collectively provided the opportunity to perform hysteroscopic and resectoscopic surgery in a manner that minimizes risk to the patient.

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

Diathermy is known to produce a mixture of waste products including carbon monoxide. During transcervical hysteroscopic surgery, carbon monoxide might enter the circulation leading to the formation of carboxyhaemoglobin. In 20 patients scheduled for transcervical hysteroscopic resection of myoma or endometrium, carboxyhaemoglobin was measured before and at the end of the surgical procedure, and compared with levels measured in 20 patients during transurethral prostatectomy, and in 20 patients during tonsillectomy. Haemodynamic data, including ST-segment changes, were recorded. Levels of carboxyhaemoglobin increased significantly during hysteroscopic surgery from median (IQR [range]) 1.0% (0.7-1.4 [0.5-4.9])% to 3.5% (2.0-6.1 [1.3-10.3]%, p < 0.001), compared with levels during prostatectomy or tonsillectomy. Significant ST-segment changes were observed in 50% of the patients during hysteroscopic surgery. Significant correlations were observed between the increase in carboxyhaemoglobin and the maximum ST-segment change (ρ = -0.707, p < 0.01), between the increase in carboxyhaemoglobin and intravasation (ρ = 0.625; p < 0.01), and between intravasation and the maximum ST-segment change (ρ = -0.761; p < 0.01). The increased carboxyhaemoglobin levels during hysteroscopic surgery appear to be related to the amount of intravasation and this could potentially be a contributing factor to the observed ST-segment changes.

Hysteroscopy: guidelines for clinical practice from the French College of Gynaecologists and Obstetricians

The objective of this study was to provide guidelines for clinical practice from the French College of Obstetrics and Gynecology (CNGOF), based on the best evidence available, concerning hysteroscopy. Vaginoscopy should be the standard technique for diagnostic hysteroscopy (Grade A) using a miniature (≤3.5mm sheath) (Grade A) rigid hysteroscope (Grade C), using normal saline solution distension medium (Grade C), without any anaesthesia (conscious sedation should not be routinely used), without cervical preparation (Grade B), without vaginal disinfection and without antibiotic prophylaxy (Grade B). Misoprostol (Grade A), vaginal oestrogens (Grade C), or GnRH agonist routine administration is not recommended before operative hysteroscopy. Before performing hysteroscopy, it is important to purge the air out of the system (Grade A). The uterine cavity distention pressure should be maintained below the mean arterial pressure and below 120mm Hg. The maximum fluid deficit of 2000ml is suggested when using normal saline solution and 1000ml is suggested when using hypotonic solution. When uterine perforation is recognized during operative hysteroscopy using monopolar or bipolar loop, the procedure should be stopped and a laparoscopy should be performed in order to eliminate a bowel injury. Diagnostic or operative hysteroscopy is allowed when an endometrial cancer is suspected (Grade B). Implementation of this guideline should decrease the prevalence of complications related to hysteroscopy.

[Prevention of the complications related to hysteroscopy: guidelines for clinical practice]

OBJECTIVE

To provide clinical practice guidelines (CPGs) from the French college of obstetrics and gynecology (CNGOF), based on the best evidence available, concerning the adverse events related to hysteroscopy.

MATERIALS AND METHODS

Review of literature using following Keywords: hysteroscopy; vaginoscopy; infection; perforation; intrauterine adhesions

RESULTS

Vaginoscopy should be the standard technique for outpatient hysteroscopy (grade A) using a miniature (≤ 3.5mm sheath) (grade A) rigid hysteroscope (grade C), using normal saline solution distension medium (grade C), without any anesthesia (conscious sedation should not be routinely used), without cervical preparation (grade B), without vaginal disinfection and without antibiotic prophylaxy (grade B). Misoprostol (grade A), vaginal estrogens (grade C), or GnRH agonist routine administration is not recommended before operative hysteroscopy. Before performing hysteroscopy, it is important to purge the air out of the system (grade A). The uterine cavity distention pressure should be maintained below the mean arterial pressure and below 120 mmHg. The maximum fluid deficit of 2000 mL is suggested when using normal saline solution and 1000 mL is suggested when using hypotonic solution. When uterine perforation is recognized during operative hysteroscopy using monopolar or bipolar loop, the procedure should be stopped and a laparoscopy should be performed in order to eliminate a bowel injury. Diagnostic or operative hysteroscopy is allowed when an endometrial cancer is suspected (grade B).

CONCLUSION

Implementation of this guideline should decrease the prevalence of complications related to office and operative hysteroscopy.

Gas embolism during hysteroscopic surgery using bipolar or monopolar diathermia: a randomized controlled trial

OBJECTIVE

The objective of the study was to determine the incidence and amount of gas embolism during hysteroscopic surgery using either monopolar or bipolar diathermia and to investigate the relationship between the severity of gas embolism and the amount of intravasation of distension fluid.

STUDY DESIGN

This was a randomized, observer-blinded trial. Fifty patients, scheduled for hysteroscopic surgery, were assigned to either monopolar or bipolar diathermia. Transesophageal echocardiography was used to detect and classify gas embolism (grade 0-IV). Intravasation of distension fluid was measured.

RESULTS

Venous gas embolism was observed in all but 1 patient. A higher incidence of more extensive (grade IV) was seen during bipolar diathermia (42% vs 13%; P = .031). Paradoxical embolism was observed in 2 patients. When intravasation exceeded 1000 mL, significantly more grade IV venous gas embolism was seen (P = .049).

CONCLUSION

During hysteroscopic surgery, gas embolism was equally observed irrespective of the type of diathermia. However, more extensive embolism was observed when intravasation of distension fluid exceeded 1 L. These results question the acceptance of up to 2500 mL intravasation of distension fluid if bipolar diathermia is used.