Gastric Point-of-Care Ultrasound Diagnosis of Unexpected Gastrointestinal Dysfunction During ICU Ward Rounds: A Case Report

Introduction

Gastrointestinal (GI) dysfunction is rather common in the intensive care unit (ICU) setting [1]. Significant gut function and motility variations are associated with the body’s posture and movement, motility pacemaker cell activation, neurohumoral signals, intestinal epithelial barrier, and GI flora composition and behavior [1]. GI dysfunction, which affects 60% of critically ill patients [1], typically includes gastroparesis, a delay in emptying caused by damage to autonomic neurons in the gastric wall or gastric pacemaker cells due to drugs, infection, operations, or underlying disease. Symptoms range from nausea and vomiting to abdominal distention and elevated intrabdominal pressure and can result in pulmonary aspiration, regurgitation, pneumonia, abdominal compartment syndrome, delayed enteral nutrition, and, therefore, insufficient calorie intake [2]. Eventually, ICU length of stay and mortality rise.

Clear definitions of delayed gastric emptying differ, as do the techniques for evaluating gastroparesis [2]. As gastric aspirates are increasingly recognized as an inefficient and unreliable method of gastric evaluation [2], the technology of point-of-care ultrasound (POCUS) provides real-time identification of gastric dynamics [1]. POCUS refers to the use of portable ultrasound performed in real time at a patient’s bedside by the treating clinician to answer specific diagnostic questions, guide procedures, and perform focused assessments rapidly and safely. POCUS as an extension of physical examination during ICU rounds is gaining popularity [3]. A recent systematic review on ultrasound assessment of gastric contents attributes a sensitivity of 95% and specificity of 88% to the technique [4]. Nevertheless, as an operator-dependent approach, considerable attention must be made to protocol implementation and competence acquisition. Gastric POCUS appears to be a promising new method for diagnosing difficulties with stomach motility, correct nasogastric tube placement, and gastric accommodation of nutrition [1,2], as well as preventing complications, including aspiration [5–7].

Case Report

We present a case of a 50-year-old male patient who had been transferred to the ICU from the oncology ward due to suspicion of cytokine release syndrome and the likelihood of coinfection. The patient was on fifth-line treatment for multiple myeloma when he developed fever, tachypnea, tachycardia, and hypotension. While in the ICU and after initial stabilization, clinical exploration and initial laboratory workup, the patient’s level pf consciousness deteriorated (a Glasgow Coma Scale drop from 15 to 11). However, as the patient’s clinical presentation was stable, a decision to schedule brain magnetic resonance imaging (MRI) was made. The patient was claustrophobic and required mild sedation for the MRI procedure.

Upon routine performance of POCUS (lung ultrasound, cardiac ultrasound gastric ultrasound, and Venous Excess Ultrasound (VExUS) on the patient, as per our ICU’s protocol, and while on the parasternal long axis view for cardiac evaluation, a formation was noticed below the cardiac chambers (Figure 1).

To further investigate the observed formation, a curvilinear low frequency probe was positioned along the midline sagittal plane, just inferior to the xiphoid process. The probe marker was oriented toward the patient’s head, and the patient was placed in a supine position. Upon probe placement, the image shown in Figure 2 was obtained.

By further tilting the probe, an overdistended gastric antrum containing solid material was visualized (Figure 3). The presence of solid gastric contents during qualitative assessment led to a grade 2 classification of the gastric antrum, which is associated with a high risk of bronchopulmonary aspiration [7].

The patient had been on total parenteral nutrition without oral intake for the preceding 7 days. He reported no abdominal distension, and physical examination revealed no signs of abdominal overdistention or tenderness.

Given the detection of solid and liquid gastric contents and the grade 2 antral classification, a nasogastric tube was inserted to decompress the stomach (Figure 3). Consequently, the scheduled MRI was postponed to allow for re-evaluation after gastric decompression. Given the elevated risk of regurgitation and aspiration, and because the patient’s neurological status allowed for deferment, imaging was rescheduled for the following day. Additionally, triple prokinetic therapy consisting of cinitapride, metoclopramide, and erythromycin was initiated.

A follow-up gastric ultrasound performed 24 hours later demonstrated a reduction in antral size and improvement in contents (Figure 4). These findings permitted safe transfer of the patient for the MRI, minimizing the risk of gastric content regurgitation and aspiration.

Discussion

We present the case of a critical care patient with occult severe gastrointestinal dysfunction, which was discovered during routine gastric POCUS during ICU rounds. Gastric POCUS averted additional complications, such as aspiration, during the patient’s diagnostic workup. Aspiration of oropharyngeal or contents in the ICU setting, where the patients frequently lack protective defense mechanisms, may result in the development of entities such as aspiration pneumonia or chemical pneumonitis, further complicating the management of critically ill patients [6]. Gastric ultrasound is an important component of the Ultrasound for Occult Hemorrhage protocol, in which visualization of the gastric antrum (station 1D) is critical for identifying potential occult bleeding through the assessment of gastric content, especially in situations requiring emergency intubation, where the risk of aspiration is significantly increased. This demonstrates the adaptability of gastric ultrasonography in the ICU setting [8].

GI dysfunction is highly prevalent among critical care patients [1]. Symptoms include nausea and vomiting, abdominal distention, and elevated intra-abdominal pressure [1,2], all of which were absent in our instance. As classification of GI dysfunction differs between scientific societies, so do approaches toward GI monitoring in the ICU. Various modalities have been used to assess GI dysfunction and halt its negative effects on mortality and ICU length of stay, ranging from scoring systems that assess bedside symptoms and abdominal signs, intra-abdominal pressure measurements, prokinetic application, and gastric residual volume estimations to biomarkers as a form of functional GI measurements [9]. Residual gastric volume measurement, one of the primary methods for guiding enteral nutrition in the ICU, has long been criticized as an unreliable assessment of GI dysfunction and nutrition tolerance [2], because it is influenced by factors such as patient posture, feeding tube characteristics, and enteral nutrition’s mode of delivery [2]. Furthermore, gastric residual volume measurements are unreliable in preventing problems in critical care patients [1].

The majority of critically ill patients experience gastroparesis and delayed emptying. Mirbagheri et al [10] emphasize that gastric function can be utilized as a surrogate for GI dysfunction and that gastric antrum measurements can quantify gastric content and volume motility across time by measuring changes in the cross-sectional antral area (CSA). As a result, research has focused on the use of gastric POCUS as a reliable bedside objective technique that is rapid and noninvasive and can support clinical decision making regarding enteral feeding and airway manipulation [1–3].

Van de Putte et al [5] and Perlas et al [7] were among the first to investigate volume and content using ultrasonographic antrum measurements in the perioperative context, to prevent complications such as pulmonary aspiration. In the critical care context, aside from its role in nutrition [1,2], Koenig et al [6] investigated the effectiveness of ultrasound in preventing aspiration during emergency endotracheal intubation in critical care units. Pereira et al [11] used gastric ultrasonography as an adjuvant to treat increasing intrabdominal pressure in the ICU. The above studies, whether in the perioperative setting or the ICU, highlight the role of gastric POCUS as a bedside tool in monitoring nutrition accommodation and patient response to nutrition, gastric emptying and motility, and aspiration risk perioperatively and during airway manipulation in the ICU.

Perlas et al [7] established a linear relationship between CSA and gastric volume, resulting in a mathematical formula for volume prediction as a function of CSA, patient height, and age. The same researchers concluded that a CSA less than 10 cm2 correlates with baseline gastric secretions, conveying no aspiration risk (normal low volume state) whereas a CSA over 10 cm2 (a predicted volume >1.5 mL/kg) with a high volume state equal to that of a full stomach. In our case, a qualitative examination of our patient’s antrum revealed the presence of fluid and solid components (Figure 3). The computed CSA was 8.1 cm2, which is less than the recommended cutoff value of 10 cm2. However, according to the algorithm proposed by Van de Putte et al [5], a grading of 2 during qualitative assessment does not necessitate extra quantitative measurement of CSA with subsequent volume estimation. A grade 2 categorization is sufficient for placing the patient in the “at-risk” group. One could argue that such cutoff thresholds were introduced in the perioperative context rather than the critical care setting. The study by Hamada et al [12], which focused on ICU patients, identified a cutoff value of 0.8 mL/kg of body weight for defining an “at-risk stomach” by gastric ultrasonography.

In our case, gastric ultrasound not only changed the treatment strategy for the patient’s neurological deterioration, but it also led to the insertion of a nasogastric tube and the implementation of prokinetic therapy to alleviate the observed paresis and increased residual gastric volume. According to the most recent guidelines from the European Society for Clinical Nutrition and Metabolism [13], erythromycin, which stimulates motilin receptors and is more efficacious, is the first-line medication for improving GI motility. Supplementary metoclopramide treatment has been shown to have a synergistic effect [13]. Consequently, in high-risk patients with gastrointestinal dysfunction, combination therapy is recommended as a targeted treatment rather than for prophylactic use. In our case, both metoclopramide and erythromycin were used. The third medicine was cinitapride, a 5-hydroxytryptamine (5-HT)1 and 5-HT4 receptor agonist with prokinetic that is extensively used in Spain and is administered concurrently in situations of delayed emptying, according to our ICU’s protocol. There were no adverse medication responses reported during our patient’s treatment. Drug administration continued for 3 days, after which, gastric antrum imaging and clinical evaluation allowed treatment to be de-escalated.

Conclusions

We conclude that antrum visualization with POCUS is a diagnostic tool that can be used during routine ICU assessment as part of an integrated and step-by-step diagnostic approach that correlates with the clinical situations and guides treatment. Because gastric residuals are no longer a valid way to assess GI dysfunction, due to subjective factors in their measurement, ultrasonographic assessment of gastric dynamics (CSA diameter changes, motility, tube positioning, and volume) is a radiation-free, noninvasive, and user-friendly method for GI evaluation. However, large, randomized controlled trials are required before evaluating if POCUS can be used as an extension of physical examination for diagnosis.