A 6th Vital Sign--Potential Use of Nasogastric Tube for Intra-abdominal Pressure Monitoring Method to Detect Feeding Intolerance in Very Low Birth-Weight Preterm Infants (<1500 g)

Predicting intra-abdominal hypertension using anthropometric measurements and machine learning

Almost one in four critically ill patients suffer from intra-abdominal hypertension (IAH). Currently, the gold standard for measuring intra-abdominal pressure (IAP) is via the bladder. Measurement of IAP is important to identify IAH early and thus implement appropriate management in order to avoid complications. It may be possible to use anthropometric parameters to predict IAP and thus identify IAH non-invasively. This retrospective observational study investigated how the most relevant body parameters evolve in relation to IAP, and whether IAP can be predicted based on anthropometric parameters. The IAP and 28 body parameters of 96 critically ill patients were recorded. Following statistical analyses such as Pearson's and mutual information correlation, the collected data were used to train a simulation model to examine reliable relationships between IAP, predict IAP values, and detect IAH. Three metrics were shown to sufficiently predict intra-bladder pressure (IBP) with a Pearson's correlation of 0.75 (R2 = 0.56). These parameters are the difference between the convex and horizontal xiphoid-to-pubis distance, sagittal abdominal diameter, and abdominal compliance. Subsequently, we found 1 metric that is able to predict the presence of IAH with Pearson correlation of 0.89 (R2 = 0.79). This metric is the difference between the convex and horizontal xiphoid to pubis distance. Three measured body parameters showed a correlation of more than 50% with IBP and they are sufficient for a reliable prediction of IBP, however, IAH can be most reliably predicted based on the difference between the convex and horizontal xiphoid-pubis distance and sagittal abdominal diameter. Future studies with larger patient populations and diverse body shapes are warranted to confirm these findings.

An Introduction to Ventra: A Programmable Abdominal Phantom for Training, Educational, Research, and Development Purposes

BACKGROUND

Intra-abdominal pressure (IAP) is a critical parameter in the care of critically ill patients, as elevated IAP can lead to reduced cardiac output and organ perfusion, potentially resulting in multiple organ dysfunction and failure. The current gold standard for measuring IAP is an indirect technique via the bladder. According to the Abdominal Compartment Society's Guidelines, new measurement methods/devices for IAP must be validated against the gold standard.

OBJECTIVES

This study introduces Ventra, an abdominal phantom designed to simulate different IAP levels, abdominal compliance, respiration-related IAP variations, and bladder dynamics. Ventra aims to facilitate the development and validation of new IAP measurement devices while reducing reliance on animal and cadaveric studies. Additionally, it offers potential applications in training and education for biomedical engineering students. This study provides a thorough explanation on the phantom's design and fabrication, which provides a low-cost solution for advancing IAP measurement research and education. The design concept, technical aspects, and a series of validation experiments determining whether Ventra is a suitable tool for future research are presented in this study.

METHODS

Ventra's performance was evaluated through a series of validation tests using a pressure gauge and two intra-gastric (Spiegelberg and CiMON) and two intra-bladder (Accuryn and TraumaGuard) pressure measurement devices. The mean and standard deviation of IAP recordings by each device were investigated. Bland-Altman analysis was used to evaluate bias, precision, limits of agreement, and percentage error for each system. Concordance analysis was performed to assess the ability of Ventra in tracking IAP changes.

RESULTS

The phantom demonstrated excellent agreement with reference pressure measurements, showing an average bias of 0.11 ± 0.49 mmHg. A concordance coefficient of 100% was observed for the phantom as well. Ventra accurately simulated different abdominal compliances, with higher IAP values resulting in lower compliance. Abdominal volume changes showed a bias of 0.08 ± 0.07 L/min, and bladder fill volume measurements showed an average difference of 0.90 ± 4.33 mL for volumes ranging from 50 to 500 mL.

CONCLUSION

The validation results were in agreement with the research guidelines of the world abdominal society. Ventra is a reliable tool that will facilitate the development and validation of new IAP measurement devices. It is an effective educational tool for biomedical engineering students as well.

Evaluation of the TraumaGuard Balloon-in-Balloon Catheter Design for Intra-Abdominal Pressure Monitoring: Insights from Pig and Human Cadaver Studies

Introduction: Intra-abdominal pressure (IAP) monitoring is crucial for the detection and prevention of intra-abdominal hypertension (IAH) and abdominal compartment syndrome (ACS). In the 1970s, air-filled catheters (AFCs) for urodynamic studies were introduced as a solution to overcome the limitations of water-perfused catheters. Recent studies have shown that for correct IAP measurement with traditional AFC, the bladder needs to be primed with 25 mL of saline solution to allow pressure wave transmission to the transducer outside of the body, which limits continuous IAP monitoring. Methods: In this study, a novel triple balloon, air-filled TraumaGuard (TG) catheter system from Sentinel Medical Technologies (Jacksonville, FL, USA) with a unique balloon-in-balloon design was evaluated in a porcine and cadaver model of IAH via laparoscopy (IAPgold). Results: In total, 27 and 86 paired IAP measurements were performed in two pigs and one human cadaver, respectively. The mean IAPTG was 20.7 ± 10.7 mmHg compared to IAPgold of 20.3 ± 10.3 mmHg in the porcine study. In the cadaver investigation, the mean IAPTG was 15.6 ± 10.8 mmHg compared to IAPgold of 14.4 ± 10.4 mmHg. The correlation, concordance, bias, precision, limits of agreement, and percentage error were all in accordance with the WSACS (Abdominal Compartment Society) recommendations and guidelines for research. Conclusions: These findings support the use of the TG catheter for continuous IAP monitoring, providing early detection of elevated IAP, thus enabling the potential for prevention of IAH and ACS. Confirmation studies with the TraumaGuard system in critically ill patients are warranted to further validate these findings.

Feasibility analysis of a novel non-invasive ultrasonographic method for the measurement of intra-abdominal pressure in the intensive care unit

Increased intra-abdominal pressure (IAP) is an important vital sign in critically ill patients and has a negative impact on morbidity and mortality. This study aimed to validate a novel non-invasive ultrasonographic approach to IAP measurement against the gold standard intra-bladder pressure (IBP) method. We conducted a prospective observational study in an adult medical ICU of a university hospital. IAP measurements using ultrasonography by two independent operators, with different experience levels (experienced, IAPUS1; inexperienced, IAPUS2), were compared with the gold standard IBP method performed by a third blinded operator. For the ultrasonographic method, decremental external pressure was applied on the anterior abdominal wall using a bottle filled with decreasing volumes of water. Ultrasonography looked at peritoneal rebound upon brisk withdrawal of the external pressure. The loss of peritoneal rebound was identified as the point where IAP was equal to or above the applied external pressure. Twenty-one patients underwent 74 IAP readings (range 2-15 mmHg). The number of readings per patient was 3.5 ± 2.5, and the abdominal wall thickness was 24.6 ± 13.1 mm. Bland and Altman's analysis showed a bias (0.39 and 0.61 mmHg) and precision (1.38 and 1.51 mmHg) for the comparison of IAPUS1 and IAPUS2 and vs. IBP, respectively with small limits of agreement that were in line with the research guidelines of the Abdominal Compartment Society (WSACS). Our novel ultrasound-based IAP method displayed good correlation and agreement between IAP and IBP at levels up to 15 mmHg and is an excellent solution for quick decision-making in critically ill patients.

In Vitro Validation of a Novel Continuous Intra-Abdominal Pressure Measurement System (TraumaGuard)

Introduction: Intra-abdominal pressure (IAP) has been recognized as an important vital sign in critically ill patients. Due to the high prevalence and incidence of intra-abdominal hypertension in surgical (trauma, burns, cardiac) and medical (sepsis, liver cirrhosis, acute kidney injury) patients, continuous IAP (CIAP) monitoring has been proposed. This research was aimed at validating a new CIAP monitoring device, the TraumaGuard from Sentinel Medical Technologies, against the gold standard (height of a water column) in an in vitro setting and performing a comparative analysis among different CIAP measurement technologies (including two intra-gastric and two intra-bladder measurement devices). A technical and clinical guideline addressing the strengths and weaknesses of each device is provided as well. Methods: Five different CIAP measurement devices (two intra-gastric and three intra-vesical), including the former CiMON, Spiegelberg, Serenno, TraumaGuard, and Accuryn, were validated against the gold standard water column pressure in a bench-top abdominal phantom. The impacts of body temperature and bladder fill volume (for the intra-vesical methods) were evaluated for each system. Subsequently, 48 h of continuous monitoring (n = 2880) on top of intermittent IAP (n = 300) readings were captured for each device. Using Pearson's and Lin's correlations, concordance, and Bland and Altman analyses, the accuracy, precision, percentage error, correlation and concordance coefficients, bias, and limits of agreement were calculated for all the different devices. We also performed error grid analysis on the CIAP measurements to provide an overview of the involved risk level due to wrong IAP measurements and calculated the area under the curve and time above a certain IAP threshold. Lastly, the robustness of each system in tracking the dynamic variations of the raw IAP signal due to respirations and heartbeats was evaluated as well. Results: The TraumaGuard was the only technology able to measure the IAP with an empty artificial bladder. No important temperature dependency was observed for the investigated devices except for the Spiegelberg, which displayed higher IAP values when the temperature was increased, but this could be adjusted through recalibration. All the studied devices showed excellent ability for IAP monitoring, although the intra-vesical IAP measurements seem more reliable. In general, the TraumaGuard, Accuryn, and Serenno showed better accuracy compared to intra-gastric measurement devices. On average, biases of +0.71, +0.93, +0.29, +0.25, and -0.06 mm Hg were observed for the CiMON, Spiegelberg, Serenno, TraumaGuard, and Accuryn, respectively. All of the equipment showed percentage errors smaller than 25%. Regarding the correlation and concordance coefficients, the Serenno and TraumaGuard showed the best results (R2 = 0.98, p = 0.001, concordance coefficient of 99.5%). Error grid analysis based on the Abdominal Compartment Society guidelines showed a very low associated risk level of inappropriate treatment strategies due to erroneous IAP measurements. Regarding the dynamic tracings of the raw IAP signal, all the systems can track respiratory variations and derived parameters; however, the CiMON was slightly superior compared to the other technologies. Conclusions: According to the research guidelines of the Abdominal Compartment Society (WSACS), this in vitro study shows that the TraumaGuard can be used interchangeably with the gold standard for measuring continuous IAP, even in an empty artificial bladder. Confirmation studies with the TraumaGuard in animals and humans are warranted to further validate these findings.

Abdominal Wall Movements Predict Intra-Abdominal Pressure Changes in Rats: A Novel Non-Invasive Intra-Abdominal Pressure Detection Method

(1) Background: As increases in intra-abdominal pressure (IAP) result in irreversible tissue damage, monitoring IAP in critically ill patients using the common urinary bladder catheter method is essential. However, this method can result in complications and is not suitable for very low birth weight neonates. The aim of this study was to establish a non-invasive and accurate method to detect IAP changes using an animal model. (2) Methods: IAP changes via intra-abdominal air application (up to 20 mmHg) were measured in 19 Wistar rats via an intra-abdominally placed intracranial pressure probe. Concurrently, abdominal surface tension was measured using a Graseby capsule (GC). (3) Results: A high correlation between abdominal wall distension and IAP (r = 0.9264, CI 0.9249-0.9279) was found for all subjects. (4) Conclusions: IAP changes in rats can be detected non-invasively using a GC. However, further studies are necessary to assess whether IAP changes can be measured using a GC in the neonatal population.

Oro-Motor Intervention Protocol to Improve Sucking Behavior among Neonates with Immature Sucking: An Experimental Protocol

Background:

Oro-motor intervention methods were previously adopted to improve the sucking pattern but there is still a lag in the structured protocol for improving sucking behavior in infants with immature sucking. Thus, this study is aimed to develop a structured protocol for the Oro-motor intervention to improve sucking behavior.

Method:

Using the prospective observational study design, neonates with poor suck (producing less than 10 sucks per minute), under NG tube feeding, and maintaining oxygen saturation at room air were included. A total of 6 subjects were enrolled in this study and they were treated with Oro-motor intervention protocol. The Sucking rate and LATCH score were taken as the outcome measures and measured at beginning of intervention and after 2 weeks of intervention.

Result:

The mean pre-test and post-test values for sucking rate were is (8.66), (32.5) and LATCH were (4.66), (8.16) respectively. The data collected showed that the protocol framed for Oro-motor intervention was significantly effective in improving quality of feeding among infants with immature sucking behavior.

Conclusion:

The structured Oro-motor intervention protocol improves the feeding performance in infants with poor sucking behavior and improves the LATCH score. All the infants included in this study where under nasogastric tube feeding, thus the structured protocol can be considered to be helpful in weaning from NG tube feeding.

Management of abdominal distension in the preterm infant with noninvasive ventilation: Comparison of cenit versus 2x1 technique for the utilization of feeding tube

BACKGROUND

Preterm infants are fed by orogastric / nasogastric tube until they reach maturation and coordination of sucking, swallowing and respiration at approximately 32-34 weeks of corrected age. While being on non-invasive ventilation (NIV), they frequently present abdominal distension. Currently at our institution two techniques are used for the management of abdominal distension in preterm infants fed by bolus via orogastric tube: cenit and 2 x 1.The aim of this study was to compare the proportion of preterm infants presenting NIV-associated abdominal distension with each of these techniques.

STUDY DESIGN

We conducted a randomized clinical trial including infants of <  36.6 weeks of gestation and <  1500 g of birth weight who were admitted to our NICU during the period of April 1, 2016 to April 1, 2018 and received NIV. The presence of abdominal distension >  2 cm was the primary outcome. Secondary outcomes were presence of reflux, regurgitation, oxygen saturation during feeding and days to reach full feedings. Feeding tube drainage, stool characteristics and the use of prokinetics were confounding variables.

RESULTS

A total of 97 patients were included. Forty-six in the cenit group and 51 in the 2 x 1 group. There was no difference in the proportion of infants with abdominal distension >  2 cm between groups. Oxygen saturation during feeding at volume of 150 ml/kg/day was higher in the cenit group with statistical significance.

CONCLUSION

The use of cenit or 2 x 1 technique in preterm infants with NIV did not improve abdominal distension or other indicators of feeding tolerance.

Early minimal breastfeeding combined with assisted intervention to improve feeding intolerance in low-birth-weight preterm infants

AIM

To observe whether early minimal breastfeeding combined with assisted intervention improves feeding intolerance in low-birth-weight preterm infants.

METHODS

Eighty-four low-birth-weight premature infants hospitalized at our hospital from October 2015 to July 2017 were randomly and equally divided into a control group and an observation group. Both groups were given intravenous nutrition treatment and routine care, and the observation group was additionally given early minimal breastfeeding combined with assisted intervention. The improvement of feeding intolerance, evaluated by times to disappearance of abdominal distension, vomiting and gastric retention, and feeding-related situations, such as times to full enteral nutrition and recovery of birth weight and length of hospital stay, were compared between the two groups.

RESULTS

After intervention, the amount of feeding, weight gain, and sleep time in the observation group were 6.4 d ± 0.8 d, 426.5 d ± 28.2 d, and 22.3 d ± 0.8 d, respectively, all of which were significantly better than those of the control group (P < 0.05). The times to total enteral nutrition and recovery of birth weight and length of hospitalization were 11.2 d ± 5.1 d, 7.3 d ± 3.2 d, and 52.5 d ± 4.3 d, respectively, all of which were significantly earlier than those of the control group (P < 0.05).

CONCLUSION

Early minimal breastfeeding combined with assisted intervention can improve gastrointestinal function and feeding intolerance in low-birth-weight premature infants.

Intra-abdominal pressure: Time ripe to revise management guidelines of acute pancreatitis?

AIM

To systematically review evidence on pathophysiology of intra-abdominal pressure (IAP) in acute pancreatitis (AP) with its clinical correlates.

METHODS

Systematic review of available evidence in English literature with relevant medical subject heading terms on PubMed, Medline and Scopus with further search from open access sources on internet as suggested by articles retrieved.

RESULTS

Intra-abdominal hypertension (IAH) is increasingly gaining recognition as a point of specific intervention with potential to alter disease outcome and improve mortality in AP. IAH can be expected in at least 17% of patients presenting with diagnosis of AP to a typical tertiary care hospital (prevalence increasing to 50% in those with severe disease). Abdominal compartment syndrome can be expected in at least 15% patients with severe disease. Recent guidelines on management of AP do not acknowledge utility of surveillance for IAP other than those by Japanese Society of Hepato-Biliary-Pancreatic Surgery. We further outline pathophysiologic mechanisms of IAH; understanding of which advances our knowledge and helps to coherently align common observed variations in management related conundrums (such as fluid therapy, nutrition and antibiotic prophylaxis) with potential to further individualize treatment in AP.

CONCLUSION

We suggest that IAP be given its due place in future practice guidelines and that recommendations be formed with help of a broader panel with inclusion of clinicians experienced in management of IAH.