Direct intra-abdominal pressure monitoring via piezoresistive pressure measurement: a technical note

The development, feasibility and credibility of intra-abdominal pressure measurement techniques: A scoping review

AIM

To provide a comprehensive overview on emerging direct and alternative methods for intra-abdominal pressure (IAP) measurement techniques.

METHODS

This was a scoping review study following Arksey and Malley's framework. The PubMed, EMBASE, Web of Science, EBSCO, Scopus and ProQuest databases were searched, and we only considered studies published from 2000 as we have extended the data from two previous reviews. Original studies that reported on the development, feasibility and credibility of IAP measurement techniques were included.

RESULTS

Forty-two of 9954 screened articles were included. IAP measurement techniques include three major categories: direct, indirect and less invasive measurement techniques. Agreement analyses were performed in most studies, and some explored the safety, time expenditure and reproducibility of IAP measurement techniques.

CONCLUSIONS

Clinical data assessing the validation of new IAP measurement techniques or the reliability of established measurement techniques remain lacking. Considering the cost and invasiveness, direct measurement is not recommended as a routine method for IAP measurement and should be preserved for critically ill patients where standard techniques are contraindicated or could be inaccurate. The measurement accuracy, reliability and sensitivity of the transrectal and transfemoral vein methods remain insufficient and cannot be recommended as surrogate IAP measures. Transvesical measurement is the most widely used method, which is the potentially most easy applicable technique and can be used as a reliable method for continuous and intermittent IAP measurement. Wireless transvaginal method facilitates the quantitative IAP measurement during exercise and activity, which laying the foundations for monitoring IAP outside of the clinic environment, but the accuracy of this technique in measuring absolute IAP cannot be determined at present. Less invasive technology will become a new trend to measure IAP and has substantial potential to replace traditional IAP measurement technologies, but further validation and standardization are still needed. Medical professionals should choose appropriate measurement tools based on the advantages and disadvantages of each IAP technique in combination with assessing specific clinical situations.

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.

Systematic Review of Diagnostic Sensors for Intra-Abdominal Pressure Monitoring

Intra-abdominal pressure (IAP) is defined as the steady-state pressure within the abdominal cavity. Elevated IAP has been implicated in many medical complications. This article reviews the current state-of-the-art in innovative sensors for the measurement of IAP. A systematic review was conducted on studies on the development and application of IAP sensors. Publications from 2010 to 2021 were identified by performing structured searches in databases, review articles, and major textbooks. Sixteen studies were eligible for the final systematic review. Of the 16 articles that describe the measurement of IAP, there were 5 in vitro studies (31.3%), 7 in vivo studies (43.7%), and 4 human trials (25.0%). In addition, with the advancement of wireless communication technology, an increasing number of wireless sensing systems have been developed. Among the studies in this review, five presented wireless sensing systems (31.3%) to monitor IAP. In this systematic review, we present recent developments in different types of intra-abdominal pressure sensors and discuss their inherent advantages due to their small size, remote monitoring, and multiplexing.

Chest wall mechanics and abdominal pressure during general anaesthesia in normal and obese individuals and in acute lung injury

PURPOSE OF REVIEW

This article discusses the methods available to evaluate chest wall mechanics and the relationship between intraabdominal pressure (IAP) and chest wall mechanics during general anaesthesia in normal and obese individuals, as well as in acute lung injury/acute respiratory distress syndrome.

RECENT FINDINGS

The interactions between the abdominal and thoracic compartments pose a specific challenge for intensive care physicians. IAP affects respiratory system, lung and chest wall elastance in an unpredictable way. Thus, transpulmonary pressure should be measured if IAP is more than 12 mmHg or if chest wall elastance is compromised for other reasons, even though the absolute values of pleural and transpulmonary pressures are not easily obtained at bedside. We suggest defining intraabdominal hypertension (IAH) as IAP at least 20 mmHg and abdominal compartment syndrome (ACS) as IAP at least 20 mmHg associated with failure of one or more organs, although further studies are required to confirm this hypothesis. Additionally, in the presence of IAH, controlled mechanical ventilation should be applied and positive end-expiratory pressure individually titrated. Prophylactic open abdomen should be considered in the presence of ACS.

SUMMARY

Increased IAP markedly affects respiratory function and complicates patient management. Frequent assessment of IAP is recommended.