In recent years, it has been recognized that transesophageal echocardiography (TEE) is of great value in resuscitation of cardiac arrest. However, its safety has rarely been reported.

We present a 59-year-old male patient scheduled to undergo cardiac surgery for rheumatic heart disease. Upper gastrointestinal bleeding from a Mallory-Weiss tear appeared following cardiopulmonary resuscitation, TEE, and percutaneous cardiopulmonary bypass resuscitation when he suffered from aesthesia-related cardiac arrest. Gastrointestinal injury was diagnosed promptly and treated effectively. However, the exact etiology of gastrointestinal injury was unclear; the interaction of closed-chest cardiac massage and the application of TEE may be involved as a most possible mechanism of injury.

Serious complications should be considered when TEE is used in patients with special pathophysiological conditions.

Transesophageal echocardiography (TEE) can provide valuable diagnostic and prognostic information during cardiac arrest resuscitation[1]; but its safety in clinical practice has not been well reported[2,3]. Serious complications were observed in non-cardiopulmonary resuscitation (CPR) cases[4-7]. But in fact, the pathophysiological conditions that are unique to CPR: External chest compression, low cardiac output and percutaneous cardiopulmonary bypass resuscitation (pCPBR) may complicate the situation.

We here present a case of upper gastrointestinal bleeding from a Mallory-Weiss tear associated with TEE during successful CPR. The main purpose is to explore the pathogenesis of upper gastrointestinal bleeding in patients subjected to CPR, TEE and pCPBR. At the same time, we try to come up with some strategies that might help prevent such injury.

The final diagnosis of the presented case is an upper gastrointestinal bleeding from a Mallory-Weiss tear associated with TEE during successful CPR and pCPBR.

The therapy with intravenous administration of a histamine-2 receptor antagonist, proton pump inhibitor and thrombin product was stared. The lesion was successfully treated with mucosal clipping. As the patient was hemodynamically stable with a hematocrit of 39%, no packed red blood cells was given.

The patient was gradually awake several hours later and could move his limbs on command. He was weaned from mechanical ventilation on the fifth day after resuscitation. Endoscopy a week later revealed excellent mucosal healing. He achieved a satisfied recovery without any evidence of further upper gastrointestinal bleeding and discharged from the hospital 12 d after resuscitation with good neurological outcomes. The patient is currently followed up regularly to assess the best timing for cardiac surgery.

TEE was first described in 1976 and became a popular imaging modality in the mid-1980s[8]. Over the last four decades, TEE is used increasingly in the emergency department, perioperative procedure and critical care environment. Although generally considered to be safe, in a recent study of 22314 TEE examinations, there were 17 patients developed complications, including esophageal perforation and mucosal damage, and there were 7 deaths directly attributed to these complications, corresponding to an incidence of 0.08% and 0.03% respectively[7]. Because TEE can rapidly identify the reversible causes of arrest[9], guide the precise cannulation of extracorporeal cardiopulmonary resuscitation and optimize the treatment after the return of spontaneous circulation[10]. Therefore, TEE has been endorsed by reviews and guidelines as a well-suited imaging tool to improve cardiac arrest outcome[11-13]. While, little is known, about the rate of complications related to TEE during CPR. We found a few articles that described the safety of defibrillation during cardiac arrest while the TEE probe is in place[2]. Only in one case, in 2018, Marchandot et al[3] described a left atrial (LA) intramural hematoma detected by TEE during CPR. They considered that iterative contacts of the LA upon the TEE probe caused by chest compressions during CPR was the primary mechanism of injury. Therefore, the complications of TEE during CPR associated morbidity and mortality seems to be heavily underreported and should be watched out for.

Mallory-Weiss tear was first described in 1929 by Mallory et al[14] and Weiss et al[15]. It is defined as longitudinal, nonperforating mucosal lacerations in the gastroesophageal junction resulting in upper gastrointestinal bleeding. Both CPR and the use of TEE are considered to be risk factors for Mallory-Weiss tear[16]. In the present case, the patient had an acute onset of hematochezia, and a nasogastric tube was placed and aspirated gross blood and the endoscopic appearance was typical. All these factors jointly established the diagnosis.

The exact reason of the anesthesia-related cardiac arrest in this patient was unclear[17]. Anaphylactic shock after administering cis-atracurium during the induction of anesthesia was considered one of the most likely causes[18]. The exact etiology of gastrointestinal injury in this case was also unknown; however, the interaction of closed-chest cardiac massage and the application of TEE may be involved as a most possible mechanism of injury[14]. There may be several reasons. Firstly, it is much more difficult to insert or manipulate the TEE probe during chest compressions, causing iatrogenic trauma occasionally. Secondly, according to Urbanowicz et al[19] and Denault et al[20], the rigid echoprobe may produce a high contact pressure on the gastroesophageal junction both during manipulation and at rest. Thirdly, external chest compressions can further elevate intragastric pressure and contact pressure, which might result in laceration[21]. Low cardiac output syndrome, non-pulsatile flow from pCPBR, and administration of vasoconstrictors can cause gastrointestinal hypoperfusion and aggravate the injury to some extent[22].

Clinicians should take a risk vs benefit assessment on each individual patient before the application of TEE during CPR. The risk factors include but not limited to: Non-standard resuscitation; co-existing gastrointestinal disease or coagulopathy; periods of probe insertion and manipulation; periods of low cardiac output and non-pulsatile flow; increased frailty; and musculoskeletal disorders and the use of steroids[9,22]. TTE should be a priority. When really need to use TEE, a written or verbal informed consent is essential. TEE probe should be inserted gently with a visualization aid[23] and performed by experienced operator who have completed dedicated training[24]. For now, it is our view that a standardized and fast CPR-TEE assessment process should be established as soon as possible[25]. The transgastric view should be avoided because in this view the probe tip is closest to the site of compressions and there is a potential risk of gastric mucosal lacerations or perforation[26]. Indeed, ideally the TEE probe should be kept out of the patient's body during closed chest cardiac massage to minimize potential injury.

The use of TEE during CPR may cause gastrointestinal injury, especially when used in combination with external chest compressions and pCPBR. Therefore, particular caution should be exercised in patients with high risk factors. Avoiding TEE probe placement in the body during chest compressions may be the most critical precaution. In a word, the safety of TEE during CPR calls for more full attention and in-depth study.

We would like to express our gratitude to the cardiac perfusionist, Ming Luo, for her help in the analysis and understanding of the mechanism of CPR assisted by pCPBR.