Prevalence and mortality of abdominal compartment syndrome in severely injured patients: A systematic review

A Wireless Implantable Passive Intra-Abdominal Pressure Sensing Scheme via Ultrasonic Imaging of a Microfluidic Device

In this article, we demonstrate a wireless and passive physiological pressure sensing scheme that utilizes ultrasound imaging of an implantable microfluidic based pressure sensitive transducer. The transducer consists of a sub-mm scale pressure sensitive membrane that covers a reservoir filled with water and is connected to a hydrophobic micro-channel. Applied pressure onto the transducer deflects the membrane and pushes the water from the reservoir into the channel; the water's travelling distance in the channel is a function of the applied pressure, which is quantitatively measured by using a 40 MHz ultrasound imaging system. The sensor presents a linear sensitivity of 42 kPa/mm and a spatial resolution of 1.2 kPa/30 μm in the physiological range of abdominal compartment syndrome. Reliability assessments of the transducer confirm its ability to remain functional after more than 600 cycles of pressure up to 55 kPa over the course of 2 days. Ex vivo experimental results verify the practical capability of the technology to effectively measure pressures under a 15 mm thick porcine skin. It is anticipated that this technology can be applied to a broad range of implantable pressure measurement, by simply tuning the thickness of the thin polydimethylsiloxane membrane and the geometry of the reservoir.

A Novel Abdominal Decompression Technique to Treat Compartment Syndrome After Burn Injury

BACKGROUND

Prevalence of abdominal compartment syndrome (ACS) is estimated to be 4%-17% in severely burned patients. Although decompressive laparotomy can be lifesaving for ACS patients, severe complications are associated with this technique, especially in burn populations. This study outlines a new technique of releasing intraabdominal pressure without resorting to decompressive laparotomy.

MATERIALS AND METHODS

Ten fresh tissue cadavers were studied; none of whom had had prior abdominal surgery. Using Veress needles, abdomens were insufflated to 30 mm Hg and subsequently connected to arterial pressure transducers. Two techniques were then used to incise fascia. First, large skin flaps were raised from a midline incision (n = 5). Second, small 2 cm cutdowns at the proximal and distal extent of midaxillary, subcostal, and inguinal incisional sites were made, followed by tunneling a subfascial plane using an aortic clamp with fascial incisions made through the grooves of a tunneled vein stripper (n = 5). Pressures were recorded in the sequence of incisions mentioned previously.

RESULTS

The open midline flap technique decreased abdominal pressure from a mean pressure of 30 ± 1.8 mm Hg to 6.9 ± 5.0 mm Hg (P < 0.01). The minimally invasive technique decreased intraabdominal pressure from 30 ± 0.9 to 5.8 ± 5.2 mm Hg (P < 0.01). This technique significantly reduced intraabdominal pressure via extraperitoneal component separation and fascial release at the midaxillary, subxiphoid, and inguinal regions.

CONCLUSIONS

This technique offers the benefit of reducing the morbidity, mortality, and complications associated with an open abdomen, which may be beneficial in the burn injury population.

Abdominal compartment syndrome: Current concepts and management

Abdominal compartment syndrome occurs when 2 or more anatomic compartments have a sustained intra-abdominal pressure >20mmHg, associated with organ failure. Incidence is 2% and prevalence varies from 0% to 36.4%. A literature search was conducted utilizing different databases. Articles published from 1970 to 2018 were included, in English or Spanish, to provide the concepts, classifications, and comprehensive management in the approach to abdominal compartment syndrome, for its treatment and the prevention of severe complications associated with the entity. Intravesical pressure measurement is the standard diagnostic method. Treatment is based on evacuation of the intraluminal content, identification and treatment of intra-abdominal lesions, improvement of abdominal wall compliance, and optimum administration of fluids and tissue perfusion. Laparotomy is generally followed by temporary abdominal wall closure 5 to 7 days after surgery. Reconstruction is performed 6 to 12 months after the last operation. Abdominal compartment syndrome should be diagnosed and operated on before organic damage from the illness occurs. Kidney injury can frequently progress and is a parameter for considering abdominal decompression. Having a biomarker for early damage would be ideal. Surgical treatment is successful in the majority of cases. A multidisciplinary focus is necessary for the intensive care and reconstructive needs of the patient. Thus, efforts must be made to define and implement strategies for patient quality of life optimization.

Incidence, Outcomes, and Factors Associated with Intra-Abdominal Hypertension and Primary Abdominal Compartment Syndrome in Abdominopelvic Injury Patients

Background

The primary aim was to identify the incidence of intra-abdominal hypertension (IAH) and primary abdominal compartment syndrome (1^oACS) of abdominopelvic injury patients at Thammasat University Hospital (TUH), Thailand, and the secondary objective was to evaluate those factors that contributed to developing these conditions.

Methods

The retrospective cohort of 38 abdominopelvic injury cases was admitted to the intensive care unit at Thammasat University Hospital, from January 1^st to December 31^st, 2018. The bladder pressure was recorded every 4 hours until the urethral catheter was removed. Data of age, gender, weight, height, body mass index, injury mechanisms, initial vital signs, imaging, laboratory data, blood component requirements, abdominal organs involved, treatments including surgery and intervention radiology, abbreviated injury scale (AIS) and injury severity score (ISS), length of ICU stays, and results of treatment were all analyzed.

Results

The patients were mostly young (mean age 31.5 years), male (68.4%), and suffering from blunt trauma (89.5%). The mean maximum bladder pressure was 8.3 ± 5.2 mmHg. Six patients (15.8%) developed IAH, and one patient (2.6%) was diagnosed with 1^oACS. Two patients expired. The multivariate analysis showed the patient who had initial Cr ≥ 1.5 g/dL, lower extremity including pelvis AIS ≥3, and ISS >15 was significantly associated with the developing of IAH.

Conclusions

The incidence of IAH and 1^oACS was 15.8% and 2.6%. Predicted factors to find developing IAH were initial Cr ≥ 1.5 g/dL, lower extremity AIS ≥3, and ISS >15. We should consider awareness of IAH and 1^oACS in abdominopelvic injury patients.

Intra-abdominal pressure may be elevated in patients with open abdomen after emergent laparotomy

PURPOSE

To estimate the change in intra-abdominal pressure (IAP) among critically ill patient who were left with open abdomen and temporary abdominal closure after laparotomy, during the first 48 h after admission.

METHODS

A cohort study in a single ICU in a tertiary care hospital. All adult patients admitted to the ICU after emergent laparotomy for acute abdomen or trauma, who were left with temporary abdominal closure (TAC), were included. Patients were followed up to 48 h. IAP was routinely measured at 0, 6, 12, 24, and 48 h after admission to ICU.

RESULTS

Thirty-nine patients were included, 34 were operated due to acute abdomen and 5 due to abdominal trauma. Seventeen patients were treated with skin closure, 13 with Bogota bag, and 9 with negative pressure wound therapy (NPWT). Eleven patients (28.2%) had IAP of 15 mmHg or above at time 0, (mean pressure 19.0 ± 3.0 mmHg), and it dropped to 12 ± 4 mmHg within 48 h (p < 0.01). Reduction in lactate level (2.4 ± 1.0 to 1.2 ± 0.2 mmol/L, p < 0.01) and increase in PaO₂/FiO₂ ratio (163 ± 34 to 231 ± 83, p = 0.03) were observed as well after 48 h.

CONCLUSIONS

This is the first large report of IAP in open abdomen. Elevated IAP may be measured in open abdomen and may subsequently relieve after 48 h.

A comparison of segmented abdominopelvic fluid volumes with conventional CT signs of abdominal compartment syndrome in a trauma population

PURPOSE

To compare the utility of abdominopelvic fluid volume measurements with established computed tomography signs for refractory post-traumatic abdominal compartment syndrome.

METHODS

This retrospective observational cohort study included 64 consecutive adult trauma patients with preoperative CT and diagnosis of refractory abdominal compartment syndrome requiring decompressive laparotomy at a level I trauma referral center between 2004 and 2014. We hypothesized that abdominal fluid volume measurements would be more predictive of the need for early laparotomy than previously described conventional CT signs of refractory ACS. Abdominopelvic fluid volumes were determined quantitatively using semi-automated segmentation software. The following conventional imaging parameters were recorded: abdominal anteroposterior:transverse ratio (round belly sign); infrahepatic vena cava diameter; distal abdominal aortic diameter; largest single small bowel wall diameter; hydronephrosis, inguinal herniation; and mesenteric and body wall edema. For outcome analysis, patients were stratified into two groups: those who underwent early (< 24 h) and late (≥ 24 h) decompressive laparotomy following CT. Correlation analysis, comparison of means, and multivariate logistic regression were performed.

RESULTS

Abdominal fluid volumes (p = 0.001) and anteroposterior:transverse ratio (p = 0.009) were increased and inferior vena cava diameter (p = 0.009) was decreased in the early decompressive laparotomy group. Multivariate analysis including conventional CT variables, fluid volumes, and laboratory values revealed abdominal fluid volumes (p = 0.012; Δ in log odds of 1.002/mL) as the only independent predictor of early decompressive laparotomy.

CONCLUSIONS

Segmented abdominopelvic free fluid volumes had greater predictive utility for decision to perform early decompressive laparotomy than previously described ACS-related CT signs in trauma patients who developed refractory abdominal compartment syndrome.

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.

Effect of Increased Intra-abdominal Pressure on Liver Histology and Hemodynamics: An Experimental Study

BACKGROUND

While reduction of portal venous (PV) blood flow has been described in animal models of intra-abdominal hypertension, reports on compensatory changes in hepatic arterial (HA) flow, known as the hepatic arterial buffer response are controversial.

MATERIALS AND METHODS

Pneumoperitoneum with helium was induced in 13 piglets. Hemodynamic measurements and pathological assessment were conducted at baseline and during the three subsequent phases: Phase A: 45 minutes with a stable intra-abdominal pressure of 25 mmHg; phase B: 45 minutes with a stable intra-abdominal pressure of 40 mmHg; and phase C during which the abdomen was re-explored and reperfusion of the liver was allowed to take place.

RESULTS

Phase B pressure was significantly greater than phase A pressure in both the PV and the inferior vena cava, demonstrating a positive association between escalating intra-abdominal hypertension and the pressure in these two vessels (all p<0.001). In contrast, HA pressure was comparable between baseline and phase A, while it tended to decrease in phase B. Regarding histology, the most notable abnormality was the presence of inflammatory infiltrates and hepatocyte necrosis.

CONCLUSION

Helium-insufflation increased PV pressure with a partial compensatory decrease of HA pressure. Nonetheless, findings consistent with hepatic ischemia were observed on pathology.

Carbon monoxide and hydrogen sulphide reduce reperfusion injury in abdominal compartment syndrome

BACKGROUND

Carbon monoxide (CO)- and hydrogen sulphide-releasing molecules (CORM-3 and GYY4137, respectively) have been shown to be potent antioxidant and antiinflammatory agents at the tissue and systemic level. We hypothesized that both CORM-3 and GYY4137 would reduce the significant organ dysfunction associated with abdominal compartment syndrome (ACS).

MATERIAL AND METHODS

Randomized trial was conducted where ACS was maintained for 2 hours in 27 rats using an abdominal plaster cast and intraperitoneal CO₂ insufflation at 20 mmHg. Three experimental groups underwent ACS and received an experimental molecule at the time of decompression: inactive CORM-3, active CORM-3, and GYY4137, whereas three groups underwent no ACS to serve as a sham. Sinusoidal perfusion, inflammatory response and cell death were quantified in exteriorized livers. Respiratory, liver, and renal dysfunction was assessed biochemically.

RESULTS

Hepatocellular death and the number of activated leukocytes within postsinusoidal venules were significantly increased in rats with ACS (16-fold increase, 17-fold leukocyte activation, respectively, P < 0.05). Administration of CORM-3 or GYY4137 resulted in a significant decrease of both parameters (P = 0.03 and P = 0.009). ACS resulted in an increase in markers of renal and liver injury; CORM-3 or GYY4137 partially restored levels to those seen in sham animals. Myeloperoxidase was significantly elevated in the ACS group in lung, liver, and small intestine (P = 0.0002, P = 0.01, and P = 0.08, respectively). CORM-3 treatment, but not GYY4137, was able to completely block the response (65 ± 11 U/ml and 92 ± 18 U/ml, respectively versus 110 ± 10U/ml in the ACS group, lung tissue).

CONCLUSIONS

We have demonstrated the effect of two molecules, CO and hydrogen sulphide, on tempering the reperfusion-associated metabolic and organ derangements in ACS. CORM-3 demonstrated a greater effect than GYY4137 and was able to restore most of the measured parameters to levels comparable to sham.

Cardiopulmonary physiology: why the heart and lungs are inextricably linked

Because the heart and lungs are confined within the thoracic cavity, understanding their interactions is integral for studying each system. Such interactions include changes in external constraint to the heart, blood volume redistribution (venous return), direct ventricular interaction (DVI), and left ventricular (LV) afterload. During mechanical ventilation, these interactions can be amplified and result in reduced cardiac output. For example, increased intrathoracic pressure associated with mechanical ventilation can increase external constraint and limit ventricular diastolic filling and, therefore, output. Similarly, high intrathoracic pressures can alter blood volume distribution and limit diastolic filling of both ventricles while concomitantly increasing pulmonary vascular resistance, leading to increased DVI, which may further limit LV filling. While LV afterload is generally considered to decrease with increased intrathoracic pressure, the question arises if the reduced LV afterload is primarily a consequence of a reduced LV preload. A thorough understanding of the interaction between the heart and lungs can be complicated but is essential for clinicians and health science students alike. In this teaching review, we have attempted to highlight the present understanding of certain salient aspects of cardiopulmonary physiology and pathophysiology, as well as provide a resource for multidisciplined health science educators and students.