Abdominal compartment syndrome in trauma patients: New insights for predicting outcomes

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.

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.

Fluid Management, Intra-Abdominal Hypertension and the Abdominal Compartment Syndrome: A Narrative Review

BACKGROUND

General pathophysiological mechanisms regarding associations between fluid administration and intra-abdominal hypertension (IAH) are evident, but specific effects of type, amount, and timing of fluids are less clear.

OBJECTIVES

This review aims to summarize current knowledge on associations between fluid administration and intra-abdominal pressure (IAP) and fluid management in patients at risk of intra-abdominal hypertension and abdominal compartment syndrome (ACS).

METHODS

We performed a structured literature search from 1950 until May 2021 to identify evidence of associations between fluid management and intra-abdominal pressure not limited to any specific study or patient population. Findings were summarized based on the following information: general concepts of fluid management, physiology of fluid movement in patients with intra-abdominal hypertension, and data on associations between fluid administration and IAH.

RESULTS

We identified three randomized controlled trials (RCTs), 38 prospective observational studies, 29 retrospective studies, 18 case reports in adults, two observational studies and 10 case reports in children, and three animal studies that addressed associations between fluid administration and IAH. Associations between fluid resuscitation and IAH were confirmed in most studies. Fluid resuscitation contributes to the development of IAH. However, patients with IAH receive more fluids to manage the effect of IAH on other organ systems, thereby causing a vicious cycle. Timing and approach to de-resuscitation are of utmost importance, but clear indicators to guide this decision-making process are lacking. In selected cases, only surgical decompression of the abdomen can stop deterioration and prevent further morbidity and mortality.

CONCLUSIONS

Current evidence confirms an association between fluid resuscitation and secondary IAH, but optimal fluid management strategies for patients with IAH remain controversial.

Current Approach to the Evaluation and Management of Abdominal Compartment Syndrome in Pediatric Patients

Abdominal compartment syndrome is an emergent condition caused by increased pressure within the abdominal compartment. It can be caused by a number of etiologies, which are associated with decreased abdominal wall compliance, increased intraluminal or intraperitoneal contents, or edema from capillary leak or fluid resuscitation. The history and physical examination are of limited utility, and the criterion standard for diagnosis is intra-abdominal pressure measurement, which is typically performed via an intravesical catheter. Management includes increasing abdominal wall compliance, evacuating gastrointestinal or intraperitoneal contents, avoiding excessive fluid resuscitation, and decompressive laparotomy in select cases.

Feasibility of a Portable Abdominal Insufflation Device for Controlling Intraperitoneal Bleeding After Abdominal Blunt Trauma

Uncontrolled bleeding contributes to 30% to 40% of trauma-related deaths and is the leading cause of potentially preventable deaths. Currently, there is no effective method available to first responders for temporary control of noncompressible intraabdominal bleeding while patients are transported to the hospital. Our previous studies demonstrated that abdominal insufflation provides effective temporary bleeding control. The study aims to prove the feasibility (insufflation to a target pressure) and safety (cardiovascular and respiratory effects) of a novel portable abdominal insufflation device (PAID) designed to control the intraperitoneal bleeding caused by abdominal trauma. The PAID prototype is based on a patented design and manufactured via additive manufacturing. PAID contains a 16-g CO2cartridge and an electronic pressure transducer. PAID was tested on a bench top and a swine animal model. For the animal model study, the intraperitoneal pressure as well as cardiorespiratory parameters (hearth rate, SpO2[peripheral capillary oxygen saturation], and blood pressure) were continuously monitored during the insufflation procedure. The prototype functioned according to specifications on both bench top and animal models. CO2insufflation of the peritoneal cavity was delivered up the target 20 mm Hg and maintained for 30 minutes from 1 or 2 cartridges in the swine model. No intraoperative incidents were registered, and all the recorded physiological parameters were within normal limits. The PAID prototype is a feasible, easy to use device that provides quick, controlled, and safe insufflation of the peritoneal cavity. Future studies will focus on testing the next-generation, semiautomatic PAID prototype in a severe intraabdominal injury model.

Comparison of pressure-regulated volume control ventilation and pressure control ventilation in patients with abdominal compartment syndrome

Mechanical ventilation support is commonly required in abdominal compartment syndrome (ACS). In the present study, pressure-regulated volume control ventilation (PRVCV) was compared to pressure control ventilation (PCV) in patients with ACS. The prospective study included 40 patients with ACS who were randomized into the PCV or PRVCV groups and subjected to the different modes of ventilation. After 6 h of ventilation, arterial blood gas, respiratory mechanics and hemodynamics parameters, as well as the intra-abdominal pressure (IAP) and Sequential Organ Failure Assessment (SOFA) scores were calculated. Compared to the PCV mode, mechanical ventilation with PRVCV lead to a significant decrease in the partial pressure of carbon dioxide, the peak inspiratory pressure, the mean inspiratory pressure, the central venous pressure, the heart rate and the extravascular lung water index. In addition, a marked improvement in pH, partial pressure of oxygen, oxygenation index and pulmonary static compliance was noted. However, no significant differences in airway resistance, mean arterial pressure, or IAP and SOFA scores were obtained. In conclusion, the PRVCV mode is better than the PCV mode in ventilation patients with ACS, and should therefore be used as a lung protective strategy. The present study was registered at Chictr.org (no. ChiCTR1800016869).

Successful non-operative management of intraabdominal hypertension and abdominal compartment syndrome after complex ventral hernia repair: a case series

BACKGROUND

Intraabdominal hypertension (IAH) and abdominal compartment syndrome (ACS) are devastating complications of surgery. Patients who undergo complex ventral hernia repair (CVHR) may be at risk for IAH and ACS.

METHODS

We performed a retrospective review of 175 patients who underwent CVHR by a single surgeon. Body mass index (BMI), prior hernia repair, operative time, bladder pressure, serum creatinine, sedation, paralytic therapy, and ventilator support were reviewed.

RESULTS

IAH was identified in 33 patients; 11 patients developed ACS. Paralytic therapy was employed in 29 patients for an average of 1.4 days. Elevated BMI was independently associated with an increased risk of IAH (p = 0.006) and ACS (p = 0.02).

CONCLUSION

Patients who undergo CVHR are at risk of developing IAH and ACS in the postoperative period. Elevated BMI and longer operative time are independent risk factors for the development of IAH. IAH and ACS can be successfully managed with surgical critical care.

Acute kidney injury in trauma patients

PURPOSE OF REVIEW

To review epidemiology and pathophysiology of acute kidney injury (AKI) in trauma patients and propose strategies that aim at preventing AKI after trauma.

RECENT FINDINGS

AKI in trauma patients has been reported to be as frequent as 50% with an association to a prolonged length of stay and a raise in mortality. Among the specific risk factors encountered in trauma patients, hemorrhagic shock, rhabdomyolysis severity, age, and comorbidities are independently associated with AKI occurrence. Resuscitation with balanced solutes seems to have beneficial effects on renal outcome compared with NaCl 0.9%, particularly in the context of rhabdomyolysis. However, randomized clinical studies are needed to confirm this signal. Abdominal compartment syndrome (ACS) is rare but has to be diagnosed to initiate a dedicated therapy.

SUMMARY

The high incidence of AKI in trauma patients should lead to early identification of those at risk of AKI to establish a resuscitation strategy that aims at preventing AKI.

Reduction of Intra-abdominal Hypertension Is Associated with Increase of Cardiac Output in Critically Ill Patients Undergoing Mechanical Ventilation

Objective: To demonstrate the relationship between intra-abdominal hypertension (IAH) and cardiac output (CO) in mechanically ventilated (MV), critically ill patients.

Material and methods: This was a single-center, prospective study performed between January and April 2016, on 30 mechanically ventilated patients (mean age 67.3 ± 11.9 years), admitted in the Intensive Care Unit (ICU) of the Emergency County Hospital of Tîrgu Mureș, Romania, who underwent measurements of intra-abdominal pressure (IAP). Patients were divided into two groups: group 1 – IAP <12 mmHg (n = 21) and group 2 – IAP >12 mmHg (n = 9). In 23 patients who survived at least 3 days post inclusion, the variation of CO and IAP between baseline and day 3 was calculated, in order to assess the variation of IAP in relation to the hemodynamic status.

Results: IAP was 8.52 ± 1.59 mmHg in group 1 and 19.88 ± 8.05 mmHg in group 2 (p <0.0001). CO was significantly higher in group 1 than in the group with IAH: 6.96 ± 2.07 mmHg (95% CI 6.01–7.9) vs. 4.57 ± 1.23 mmHg (95% CI 3.62–5.52) (p = 0.003). Linear regression demonstrated an inverse correlation between CO and IAP (r = 0.48, p = 0.007). Serial measurements of CO and IAP proved that whenever accomplished, the decrease of IAP was associated with a significant increase in CO (p = 0.02).

Conclusions: CO is significantly correlated with IAP in mechanically ventilated patients, and IAH reduction is associated with increase of CO in these critically ill cases.

Effectiveness and safety of continuous neuromuscular blockade in trauma patients with an open abdomen: A follow-up study

BACKGROUND

Neuromuscular blocking agents (NMBA) have been associated with decreased time to fascial closure following damage control laparotomy (DCL). Changes in resuscitation over the last decade bring this practice into question.

METHODS

A retrospective cohort study of adults who underwent DCL between 2009 and 2015 was conducted at an ACS-verified level 1 trauma center. The study group (NMBA+) received continuous NMBA within 24 h of DCL. Data collected included demographics, resuscitative fluids, mortality, and complications. The primary outcome was time to fascial closure. Factors associated with abdominal closure were determined by ordinal logistic regression.

RESULTS

There were 222 patients included (NMBA+ 125; NMBA- 97). Demographics were similar, including median age (NMBA+ 36; NMBA- 39 years) and ISS (NMBA+ 29; NMBA- 34). There was no difference in median time to closure (NMBA+ 2; NMBA- 2 days) or the incidence of complications (NMBA+ 64%; NMBA- 59%). In a regression model, NMBA exposure was not associated with time to abdominal closure.

CONCLUSIONS

In adult trauma patients requiring DCL, continuous NMBA did not affect the time to abdominal closure.