Endoscopic retrograde cholangiopancreatography (ERCP) is a commonly performed minimally invasive procedure. Air embolism in a patient undergoing ERCP is relatively rare, accounting for approximately 2-3% of procedures performed, and a catastrophic air embolism is even rarer. Symptoms of air embolism can come from the cardiopulmonary and nervous system. It is important to remember this in the differential diagnosis of complications of ERCP, as early detection is crucial. In the case presented here, the diagnostic CT scan performed immediately after the incident brings awareness of how massive an air embolism can be. The CT results showed gas bubbles entering both the superior and inferior vena cava. The presence of air has been captured in the bile ducts, duodenum wall, heart, femoral veins and intracranially. Risk factors for this complication include previous biliary surgeries, the presence of prostheses and stents, cholangitis, liver tumors and anatomical anomalies such as hepatobiliary fistulas, as well as intrahepatic and extrahepatic anatomical leaks. As gas embolism is associated with serious health consequences, knowledge of the problem and adequate preparation may reduce the occurrence of the problem. Attention should be paid to basic and easily obtainable precautions when performing the procedure, such as the patient\'s hemodynamic status, adequate hydration and positioning during the procedure.

BACKGROUND: Gas embolism is a rare but fatal clinical emergency. Hydrogen peroxide (H2O2) can cause gas embolism when improperly used in closed cavities or for deep and large wound irrigation.
METHODS: A 31-year-old woman was diagnosed with lumbar-3 tuberculosis and paravertebral abscess and underwent emergency spinal surgery in a prone position. After removing the tuberculous pus, 200 mL of H2O2 (3 % v/w) was used to repeatedly irrigate the abscess cavity. Immediately after irrigation, the patient suffered cardiac arrest. During cardiopulmonary resuscitation, transesophageal echocardiography revealed that the right cardiac cavity was filled with a diffuse \"Snowflake-Like\" gas embolus, and cranial computed tomography showed a multi-point pneumocephalus in the frontal lobes. The patient eventually suffered brain death despite the return of spontaneous circulation after active resuscitation.
CONCLUSIONS: H2O2 can quickly release abundant oxygen and water upon contact with catalase. Oxygen bubbles enter the vascular lumen and cause mechanical obstruction of the right cardiac circulation. In addition, H2O2 and oxygen bubbles may migrate upwards and enter the intracranial tissue through the epidural space or subdural space, resulting in intracranial pneumatosis. Diagnosis and treatment of gas embolism are extremely difficult. Some suggestions are that H2O2 should not be used in closed cavities or on deep and large wounds due to the potential risk of fatal gas embolism.
CONCLUSIONS: The fatal complications of gas embolism and pneumocephalus rarely occur simultaneously in one patient, and we aim to highlight this potential risk of intraoperative H2O2 use in spinal surgery.

A mild pneumocoelom was diagnosed by computed tomography in a stranded juvenile loggerhead sea turtle (Caretta caretta). After gas extraction by ultrasound-guided puncture, the animal did not improve and was subjected to hyperbaric oxygen therapy (HBOT). After HBOT, the turtle developed marked subcutaneous emphysema and was found dead the following morning. Gross lesions included a distended right atrium with numerous gas bubbles within the epicardium, gas bubbles in the hepatic, gastric and mesenteric veins, a small gas-filled bulla in the left lung and diffuse haemorrhages in the encephalon. Histological lesions included gas-like emboli in the lumen of the right atrium with myocardial necrosis, gas-like emboli in the lumina of intestinal, pulmonary and renal blood vessels and severe meningeal haemorrhages. From a forensic pathology perspective, the subcutaneous emphysema of immediate onset after HBOT and the greater severity of the histological lesions in blood vessels, heart, lung and brain differentiate this case from other cases of gas embolism in turtles due to incidental capture. Two factors contributed to this outcome: the existence of a probably unresolved pneumocoelom and the application of HBOT without an initial diagnosis that accurately indicated its use. Therefore, as in human medicine, the use of HBOT in sea turtles with lung lesions and pneumocoelom is discouraged. This is the first description of an iatrogenic gas embolism in a sea turtle.

OBJECTIVE: Cerebral arterial gas embolism (CAGE) occurs when air or medical gas enters the systemic circulation during invasive procedures and lodges in the cerebral vasculature. Non-contrast computer tomography (CT) may not always show intracerebral gas. CT perfusion (CTP) might be a useful adjunct for diagnosing CAGE in these patients.
METHODS: This is a retrospective single-center cohort study. We included patients who were diagnosed with iatrogenic CAGE and underwent CTP within 24 h after onset of symptoms between January 2016 and October 2022. All imaging studies were evaluated by two independent radiologists. CTP studies were scored semi-quantitatively for perfusion abnormalities (normal, minimal, moderate, severe) in the following parameters: cerebral blood flow, cerebral blood volume, time-to-drain and time-to-maximum.
RESULTS: Among 27 patient admitted with iatrogenic CAGE, 15 patients underwent CTP within the designated timeframe and were included for imaging analysis. CTP showed perfusion deficits in all patients except one. The affected areas on CTP scans were in general located bilaterally and frontoparietally. The typical pattern of CTP abnormalities in these areas was hypoperfusion with an increased time-to-drain and time-to-maximum, and a corresponding minimal decrease in cerebral blood flow. Cerebral blood volume was mostly unaffected.
CONCLUSIONS: CTP may show specific perfusion defects in patients with a clinical diagnosis of CAGE. This suggests that CTP may be supportive in diagnosing CAGE in cases where no intracerebral gas is seen on non-contrast CT.

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

Scuba diving fatalities post-mortem diagnosis presents a higher level of forensic complexity because of their occurrence in a non-natural human life environment. Scuba divers are equipped with diving gas to breathe underwater. It is essential for them to be fully trained in order to be able to manage their dive safely despite the varying increase of ambient pressure and temperature decrease. Throughout the dive, the inhaled diving gas is dissolved in the diver\'s tissues during the descent and if the decompression steps are not respected during the ascent, the balance between the dissolved gas and the tissues (including blood) is disrupted, leading to a gaseous release in the organism. Depending on the magnitude of this gaseous release, free gas can occur in blood and tissue. Venous or arterial gas embolism can also occur as a consequence of decompression sickness or barotraumatism. It can also induce drowsiness that consequently leads to drowning. As a result, the occurrence of gas in dead scuba divers is very complex to interpret, as is the difficulty to distinguish it from resuscitation maneuver artifacts or body decomposition. Although the literature is scarce in this domain, significant work has been done to provide a precise intracadaveric gas sampling method to enlighten the cause and circumstances of death during the dive. The aim of this study is to obtain higher statistical significance by collecting a number of cases to confirm the gas sampling protocol and analysis and gain more information about the cause of death and the events surrounding the fatality through the establishment of clear management guidelines.

During minimally invasive surgery (MIS), surgeons create small and percutaneous incisions to access internal structures without open surgical incisions. Some MIS equipment is complex and challenging for perioperative nurses to manage. Patients also can experience life-threatening complications during MIS procedures. The updated AORN \"Guideline for minimally invasive surgery\" provides recommendations that perioperative nurses can use when caring for patients undergoing MIS procedures. This article provides an overview of the guideline and discusses several recommendations, including creating a safe environment in which to perform MIS procedures; using gas distension media, irrigation and fluid distension media, and computer-assisted navigation and robotics; and performing intraoperative magnetic resonance imaging in a hybrid OR. It also includes a scenario describing care of a patient undergoing a hysteroscopy. Perioperative nurses who care for patients undergoing MIS procedures should review the guideline in its entirety and apply the recommendations as applicable in their practice.

OBJECTIVE: Cerebral infarctions caused by air embolisms (AE) are a feared risk in endovascular procedures; however, the relevance and pathophysiology of these AEs is still largely unclear. The objective of this study was to investigate the impact of the origin (aorta, carotid artery or right atrium) and number of air bubbles on cerebral infarctions in an experimental in vivo model.
METHODS: In 20 rats 1200 or 2000 highly calibrated micro air bubbles (MAB) with a size of 85 µm were injected at the aortic valve (group Ao), into the common carotid artery (group CA) or into the right atrium (group RA) using a microcatheter via a transfemoral access, resembling endovascular interventions in humans. Magnetic resonance imaging (MRI) using a 9.4T system was performed 1 h after MAB injection followed by finalization.
RESULTS: The number (5.5 vs. 5.5 median) and embolic patterns of infarctions did not significantly differ between groups Ao and CA. The number of infarctions were significantly higher comparing 2000 and 1200 injected MABs (6 vs. 4.5; p < 0.001). The infarctions were significantly larger for group CA (median infarction volume: 0.41 mm3 vs. 0.19 mm3; p < 0.001). In group RA and in the control group no infarctions were detected. Histopathological analyses showed early signs of ischemic stroke.
CONCLUSIONS: Iatrogenic AEs originating at the ascending aorta cause a similar number and pattern of cerebral infarctions compared to those with origin at the carotid artery. These findings underline the relevance and potential risk of AE occurring during endovascular interventions at the aortic valve and ascending aorta.

Gas embolism is a rare and potentially fatal complication of endoscopic retrograde cholangiopancreatography (ERCP). We present a 66-year-old man who developed gas embolism after undergoing therapeutic ERCP for cholangitis. Some risk factors of gas embolism in this patient included stones in the common bile duct with cholangitis and a history of multiple ERCP procedures. Early diagnosis and rapid treatment of this potentially fatal complication resulted in our patient\'s full recovery.

Introduction: Gas embolism can occur during minimally invasive surgical procedures. Its incidence and implications in infants and children are not clear. The objective of this study is to identify gas embolism with transthoracic echocardiography and its consequences in pediatric laparoscopic appendectomy. Materials and Methods: This is a descriptive observational study including children undergoing laparoscopic appendectomy. We performed transthoracic echocardiography during surgery and collected data on intraoperative hemodynamic and respiratory parameters. Results: To date, we have included 10 patients in whom intraoperative transthoracic echocardiography revealed a 50% incidence of gas embolism. All episodes of embolism were grade I or II, and the patients remained asymptomatic. The hemodynamic and respiratory parameters varied slightly during the pneumoperitoneum. Conclusions: Episodes of gas embolism in pediatric laparoscopic appendectomy appeared in up to 50% of patients. Although they were subclinical, we should be aware of the risk of serious events and take measures to maximize safety in pediatric minimally invasive surgery.