Intra-abdominal hypertension among medical septic patients associated with worsening kidney outcomes (IAH-WK study).

High intra-abdominal pressure (IAP) is associated with acute kidney injury (AKI). However, the relationship between intra-abdominal hypertension (IAH) and AKI in medical septic patients is still inconclusive. This prospective cohort study enrolled patients admitted in the Medical Intensive Care Unit from April 2020 to February 2021. Demographic, therapeutic, and laboratory data were obtained upon admission. The evaluation of IAP was performed via the intra-vesical method during the first and second 24 hours of admission. Kidney function was evaluated on the first 3 days and at least on the 7th day of enrollment. Among 79 patients, 30 (38%) developed IAH, while 50 (63.3%) developed AKI within 7 days. On the first day, the mean IAP was 15.4 (interquartile range [IQR], 4) and 7.0 (IQR, 3.7) mm Hg in the IAH and non-IAH groups, respectively. A total of 52 patients (65.8%) developed the primary outcome (i.e., a composite outcome including AKI, treatment with kidney replacement therapy, or death). On Cox proportional-hazards model between IAH and outcomes, after adjustment for multiple covariates, IAH was associated with a composite outcome (hazard ratio [HR], 6.5; 95% confidence interval [CI], 2.3-18.6; P < .005) and the development of AKI (HR, 6.5; 95% CI, 2.3-18.8; P < .005). IAH was associated with a composite outcome of AKI, treatment with kidney replacement therapy, or death in medical septic patients. thaiclinicaltrial.org, Identifier: TCTR20200531001, Registered May 24, 2020.

Abdominal paracentesis drainage improves outcome of acute pancreatitis complicated with intra-abdominal hypertension in early phase.

BACKGROUND: Intra-abdominal hypertension (IAH) is an important risk factor for organ dysfunction, and it occurs in the early phase of severe acute pancreatitis (SAP). We have reported a novel step-up approach and shown the benefit of performing abdominal paracentesis drainage (APD) ahead of percutaneous catheter drainage (PCD) when treating Patients with SAP with fluid collections. This study aimed to evaluate the efficacy of APD in Patients with SAP complicated with IAH in the early phase. METHODS: In the present study, 206 AP patients complicated with IAH in the early phase were enrolled in hospital between June 2017 and December 2020. The patients were divided into two groups: 109 underwent APD (APD group) and 97 were managed without APD (non-APD group). We retrospectively compared the outcomes of the APD and non-APD groups for IAH treatment. The parameters including mortality, infection, organ failure, inflammatory factors, indications for further interventions, and drainage-related complications were observed. RESULTS: The demographic data and severity scores of the two groups were comparable. The mortality rate was lower in the APD group (3.7%) than in the non-APD group (8.2%). Compared with the non-APD group, the intra-abdominal pressure and laboratory parameters of the APD group decreased more rapidly, and the mean number of failed organs was lower. However, there was no significant difference in incidence of infections between the two groups. CONCLUSIONS: Application of APD is beneficial to AP patients. It significantly attenuated inflammation injury, avoided further interventions, and reduced multiple organ failure.

Intra-Abdominal Hypertension: A Systemic Complication of Severe Acute Pancreatitis.

Patients with severe acute pancreatitis (SAP) present complications and organ failure, which require treatment in critical care units. These extrapancreatic complications determine the clinical outcome of the disease. Intra-abdominal hypertension (IAH) deteriorates the prognosis of SAP. In this paper, relevant recent literature was reviewed, as well as the authors' own experiences, concerning the clinical importance of IAH and its treatment in SAP. The principal observations confirmed that IAH is a frequent consequence of SAP but is practically absent in mild disease. Common manifestations of AP such as pain, abdominal distension, and paralytic ileus contribute to increased abdominal pressure, as well as fluid loss in third space and aggressive fluid replacement therapy. A severe increase in IAP can evolve to abdominal compartment syndrome and new onset organ failure. Conservative measures are useful, but invasive interventions are necessary in several cases. Percutaneous drainage of major collections is preferred when possible, but open decompressive laparotomy is the final possibility in some cases in order to definitively reduce abdominal pressure. Intra-abdominal pressure should be measured in all SAP cases that worsen despite adequate treatment in critical care units. Conservative measures must be introduced to treat IAH, including negative fluid balance, digestive decompression by gastric-rectal tube, and prokinetics, including neostigmine. In the case of insufficient responses to these measures, minimally invasive interventions should be preferred.

Impact of intraabdominal hypertension on kidney failure in critically ill patients: A post-hoc database analysis.

PURPOSE: To assess whether intraabdominal hypertension (IAH) may influence kidney failure as well as mortality. METHODS: This post-hoc analysis of two databases (IROI and iSOFA study) tested the independent association between IAH and kidney failure. Mortality was assessed using four prespecified groups (IAH present, kidney failure present, IAH and kidney failure present and no IAH or kidney failure present). RESULTS: Of 825 critically ill patients, 302 (36.6%) developed kidney failure and 192 (23.7%) died during the first 90 days. Only 'Cumulative days with IAH grade II or more' was significantly associated with kidney failure (OR 1.29 (1.08-1.55), p = 0.003) while 'cumulative days with IAH grade I or more' (p = 0.135) or highest daily IAP (p = 0.062) was not. IAH combined with kidney failure was independently associated with 90-day mortality (OR 2.20 (1.20-4.05), p = 0.011), which was confirmed for higher grades of IAH (grade II or more) alone (OR 2.14 (1.07-4.30), p = 0.032) and combined with kidney failure (OR 3.25 (1.72-6.12), p < 0.001). CONCLUSIONS: This study suggest that duration as well as higher grades of IAH are associated with kidney failure and may increase mortality.

Low-Flow Acute Kidney Injury: The Pathophysiology of Prerenal Azotemia, Abdominal Compartment Syndrome, and Obstructive Uropathy.

AKI is a syndrome, not a disease. It results from many different primary and/or secondary etiologies and is often multifactorial, especially in the hospitalized patient. This review discusses the pathophysiology of three etiologies that cause AKI, those being kidney hypoperfusion, abdominal compartment syndrome, and urinary tract obstruction. The pathophysiology of these three causes of AKI differs but is overlapping. They all lead to a low urine flow rate and low urine sodium initially. In all three cases, with early recognition and correction of the underlying process, the resulting functional AKI can be rapidly reversed. However, with continued duration and/or increased severity, cell injury occurs within the kidney, resulting in structural AKI and a longer and more severe disease state with increased morbidity and mortality. This is why early recognition and reversal are critical.

Abdominal compartment syndrome: an often overlooked cause of acute kidney injury.

Abdominal compartment syndrome (ACS) is defined as any organ dysfunction caused by intra-abdominal hypertension (IAH), referred as intra-abdominal pressure (IAP) ≥ 12 mm Hg according to the World Society of Abdominal Compartment Syndrome. Abdominal compartment syndrome develops in most cases when IAP rises above 20 mmHg. Abdominal compartment syndrome, while being a treatable and even preventable condition if detected early in the stage of intra-abdominal hypertension, is associated with high rates of morbidity and mortality if diagnosis is delayed: therefore, early detection is essential. Acute kidney injury (AKI) is a common comorbidity, affecting approximately one in every five hospitalized patients, with a higher incidence in surgical patients. AKI in response to intra-abdominal hypertension develops as a result of a decline in cardiac output and compression of the renal vasculature and renal parenchyma. In spite of the high incidence of intra-abdominal hypertension, especially in surgical patients, its potential role in the pathophysiology of AKI has been investigated in very few clinical studies and is commonly overlooked in clinical practice despite being potentially treatable and reversible. Aim of the present review is to illustrate the current evidence on the pathophysiology, diagnosis and therapy of intra-abdominal hypertension and abdominal compartment syndrome in the context of AKI.

Randomized controlled trial: neostigmine for intra-abdominal hypertension in acute pancreatitis.

BACKGROUND: Intra-abdominal hypertension (IAH) in acute pancreatitis (AP) is associated with deterioration in organ function. This trial aimed to assess the efficacy of neostigmine for IAH in patients with AP. METHODS: In this single-center, randomized trial, consenting patients with IAH within 2 weeks of AP onset received conventional treatment for 24 h. Patients with sustained intra-abdominal pressure (IAP) ≥ 12 mmHg were randomized to receive intramuscular neostigmine (1 mg every 12 h increased to every 8 h or every 6 h, depending on response) or continue conventional treatment for 7 days. The primary outcome was the percent change of IAP at 24 h after randomization. RESULTS: A total of 80 patients were recruited to neostigmine (n = 40) or conventional treatment (n = 40). There was no significant difference in baseline parameters. The rate of decrease in IAP was significantly faster in the neostigmine group compared to the conventional group by 24 h (median with 25th-75th percentile: -18.7% [- 28.4 to - 4.7%] vs. - 5.4% [- 18.0% to 0], P = 0.017). This effect was more pronounced in patients with baseline IAP ≥ 15 mmHg (P = 0.018). Per-protocol analysis confirmed these results (P = 0.03). Stool volume was consistently higher in the neostigmine group during the 7-day observational period (all P < 0.05). Other secondary outcomes were not significantly different between neostigmine and conventional treatment groups. CONCLUSION: Neostigmine reduced IAP and promoted defecation in patients with AP and IAH. These results warrant a larger, placebo-controlled, double-blind phase III trial. Trial registration Clinical Trial No: NCT02543658 (registered August /27, 2015).

Hemodynamic Collapse Caused by Cardiac Dysfunction and Abdominal Compartment Syndrome in a Patient with Mitochondrial Disease.

We herein report a case of mitochondrial disease with heart and intestinal tract involvement resulting in hemodynamic collapse. A 66-year-old woman was transferred to our hospital because of cardiogenic shock. Vasopressors were administered, and a circulatory support device was deployed. However, her hemodynamics did not improve sufficiently, and we detected abdominal compartment syndrome caused by the aggravation of chronic intestinal pseudo-obstruction as a complication. Insertion of a colorectal tube immediately decreased the intra-abdominal pressure, improving the hemodynamics. Finally, we diagnosed her with mitochondrial disease, concluding that the resulting combination of acute heart failure and abdominal compartment syndrome had aggravated the hemodynamics.

Intra-abdominal hypertension and increased acute kidney injury risk: a systematic review and meta-analysis.

OBJECTIVE: The present meta-analysis aimed to determine the relationship between intra-abdominal hypertension (IAH) and an increased prevalence of acute kidney injury (AKI) and identify the associated risk factors in various patient populations, regardless of whether they were admitted to an intensive care unit. METHODS: We used three databases for the following search terms: "IAH," "abdominal compartment syndrome," "AKI," "acute kidney failure," and others. The articles retrieved were compared to identify appropriate studies published until 7 May 2020. The main outcome was AKI. RESULTS: Six studies with 344 individuals were included. The patients were divided into two main groups: the IAH and non-IAH groups. Compared with patients without IAH, patients with IAH had a higher risk of AKI (odds ratio = 2.57, 95% confidence interval: 1.55-4.26). In the subgroup and meta-regression analyses, body mass index, age, the presence or absence of burns, and cardiac surgery did not affect the risk of AKI. CONCLUSION: IAH was associated with AKI risk, and this association was not influenced by age, body mass index, the presence or absence of burns, or cardiac surgery.

Intra-abdominal hypertension and abdominal compartment syndrome in the critically ill liver cirrhotic patient-prevalence and clinical outcomes. A multicentric retrospective cohort study in intensive care.

BACKGROUND: Liver cirrhosis and ascites are risk factors for intra-abdominal hypertension (IAH) and abdominal compartment syndrome (ACS); however, data is scarce. We aimed to determine the prevalence of IAH/ACS in a population of critically ill cirrhotic patients with acute medical illness in intensive care and to assess for risk factors and clinical outcomes. METHODS: This was a multicentric retrospective cohort study including two general ICUs and pooled data from a multicentric study between January 2009 and October 2019. RESULTS: A total of 9,345 patients were screened, and 95 were included in the analysis. Mean age was 56.7±1.3 years, and 79% were male. Liver cirrhosis etiology included alcohol in 45.3% and alcohol plus hepatitis C virus in 9.5%. Precipitating events included infection in 26% and bleeding in 21% of cases. Mean severity score MELD and SAPS II were 26.2±9.9 and 48.5±15.3, respectively, at ICU admission. The prevalence of IAH and ACS was respectively 82.1% and 23.2% with a mean value of maximum IAP of 16.0±5.7 mmHg and IAH grades: absent 17.9%, I 26.3%, II 33.7%, III 17.9%, and IV 4.2%. Independent risk factors for IAH were alcoholic cirrhosis (p = 0.01), West-Haven score (p = 0.01), and PaO2/FiO2 ratio (p = 0.02); as well as infection (p = 0.048) for ACS. Overall, 28-day mortality was 52.6% associated with higher IAP and ACS, and independent risk factors were MELD (p = 0.001), white blood cell count (p = 0.03), PaO2/FiO2 ratio (p = 0.03), and lactate concentration (p = 0.04) at ICU admission. CONCLUSIONS: This study demonstrates a very high prevalence of IAH/ACS in the critically ill cirrhotic patient in intensive care. Increased IAP and ACS were associated with severity of disease and adverse outcomes and independent risk factors for IAH were alcoholic cirrhosis, hepatic encephalopathy and PO2/FiO2 ratio, as well as infection for ACS. Early diagnosis, prevention, and treatment of IAH/ACS might improve outcome in critically ill cirrhotic patients.

Intraabdominal pressure and its relation with organ dysfunction in patients scheduled for elective cesarean section: Effect of supine vs left lateral tilt position.

INTRODUCTION: Intraabdominal pressure (IAP) is related to clinical outcome of patients. It is measured as intravesical pressure through a Foley catheter in the supine position. During pregnancy, there are data showing elevated IAP and also a suggestion that it may be a false increase due to pressure on the urinary bladder by the gravid uterus in the supine position. Additionally, it is not known whether the elevated IAP during pregnancy is merely a physiological change or is associated with impairment of organ functions. We thus aimed to establish a normal value of IAP in supine (IAPsupine ) as well as 10° left lateral (IAPlateral-tilt ) positions, and their association with organ functions as well as certain maternal risk characteristics. MATERIAL AND METHODS: This prospective cross-sectional cohort study included 100 consenting parturients with term gestation posted for elective cesarean section under single-shot subarachnoid block. IAP was measured via an indwelling Foley catheter with a transducer connected to it, as per the recommended technique. Organ dysfunction was defined as Sequential Organ Failure Assessment (SOFA) subscore ≥1 for the particular system. TRIAL REGISTRATION: ctri.gov.in (CTRI/2017/11/010527). RESULTS: The IAPsupine was significantly higher than IAPlateral-tilt (13.8 ± 2.4 vs 12 ± 2.3 mm Hg) (P < .001). The incidence of intraabdominal hypertension as per conventional definition, that is, IAP ≥12 mm Hg, was also higher in the supine position (77% vs 55%) (P < .001). None of the patients had dysfunction of the cardiovascular, renal or central nervous system. The incidence of respiratory, hepatic and hematologic dysfunction was 2%, 15% and 32%, respectively. Receiver operating characteristic analysis showed insignificant association of IAPsupine and IAPlateral-tilt with various organ dysfunctions (P > .05). There was a significant correlation of intraabdominal hypertension when considering IAPsupine or IAPlateral-tilt , with obesity (P = .004 and .000, respectively), as well as preeclampsia (P = .006 and .000, respectively). CONCLUSIONS: In nonlaboring patients undergoing elective cesarean section, IAP is significantly higher in the supine vs 10° left lateral position. In neither position is IAP significantly associated with organ dysfunction. Thus, the usual recommendation of a supine position for measuring IAP to diagnose intraabdominal hypertension, formulated consequent to its pathological effects on organ functions, may not be applicable to pregnant patients and needs urgent validation studies.

Prevention of Severe Intestinal Barrier Dysfunction Through a Single-Species Probiotics is Associated With the Activation of Microbiome-Mediated Glutamate-Glutamine Biosynthesis.

INTRODUCTION: Intra-abdominal hypertension (IAH), the leading complication in the intensive care unit, significantly disturbs the gut microbial composition by decreasing the relative abundance of Lactobacillus and increasing the relative abundance of opportunistic infectious bacteria. METHODS: To evaluate the preventative effect of Lactobacillus-based probiotics on IAH-induced intestinal barrier damages, a single-species probiotics (L92) and a multispecies probiotics (VSL#3) were introduced orally to Sprague-Dawley rats for 7 days before inducing IAH. The intestinal histology and permeability to macromolecules (fluoresceine isothiocyanate, FITC-dextran, N = 8 for each group), the parameters of immunomodulatory and oxidative responses [monocyte chemotactic protein 1 (MCP-1), interleukin-1ß (IL-1ß), interleukin-4 (IL-4), interleukin-10 (IL-10), malonaldehyde, glutathione peroxidase (GSH- Px), catalase (CAT), and superoxide dismutase; N = 4 for each group], and the microbiome profiling (N = 4 for each group) were analyzed. RESULTS: Seven-day pretreatments of L92 significantly alleviated the IAH-induced increase in intestinal permeability to FITC-dextran and histological damage (P  < 0.0001), accompanied with the suppression of inflammatory and oxidative activation. The increase of MCP-1 and IL-1ß was significantly inhibited (P  < 0.05); the anti-inflammatory cytokines, IL-4, and IL-10 were maintained at high levels; and the suppression of CAT (P  <  0.05) was significantly reversed when pretreated with L92. On the contrary, no significant protective effects were observed in the VSL#3-pretreated group. Among the 84 identified species, 260 MetaCyc pathways, and 217 Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways, the protective effects of L92 were correlated with an increased relative abundance of Bacteroides finegoldii, Odoribacter splanchnicus, and the global activation of amino acid biosynthesis pathways, especially the glutamate-glutamine biosynthesis pathway. CONCLUSIONS: Seven-day pretreatment with a single-species probiotics can prevent IAH-induced severe intestinal barrier dysfunction, potentially through microbial modulation.

Hipertensão intra-abdominal e síndrome compartimental abdominal: repercussões e tratamento clínico no paciente crítico / Intra-abdominal hypertension and abdominal compartment syndrome: repercussions and clinical treatment in critically ill patients

A hipertensão intra-abdominal e a síndrome compartimental abdominal foram durante muitas décadas mal compreendidas e dissociadas de suas repercussões clínicas. Trata-se de um distúrbio que pode levar à disfunção de múltiplos órgãos devido ao desequilíbrio circulatório desencadeado pelo aumento de pressão no compartimento abdominal. As manifestações envolvem os sistemas cardiovascular, respiratório, renal, nervoso e gastrintestinal e estão largamente relacionadas com o fator de morbimortalidade no paciente crítico. A despeito da importância clínica, a hipertensão intra-abdominal e à síndrome compartimental abdominal ainda são temas pouco dominados pelos médicos, e fazem-se necessários o reconhecimento precoce e o estabelecimento de estratégias clínicas objetivas no contexto de uma síndrome com desfecho tão desfavorável. Portanto, foi realizada uma revisão da literatura não sistematizada com objetivo de compreender os principais pontos sobre definições, prevalência, fatores de risco, fisiopatologia, diagnóstico e tratamento acerca da hipertensão intra-abdominal e a síndrome compartimental abdominal.

Intra-abdominal hypertension and abdominal compartment syndrome have been, for many decades, poorly understood and dissociated from their clinical repercussions. It is a disorder that can lead to organ dysfunction due to circulatory impairment triggered by increased pressure in the abdominal compartment. The manifestations involve cardiovascular, respiratory, renal, nervous, and gastrointestinal systems, and are widely associated with significant morbidity and mortality in critically ill patients. Despite their clinical importance, intra-abdominal hypertension and abdominal compartment syndrome are still not sufficiently known by physicians and, early recognition and the establishment of objective clinical strategies for managing these highly morbid syndromes are required. Therefore, a non-systematized review was carried out to understand the main points about definitions, prevalence, risk factors, pathophysiology, diagnosis, and treatment of intra-abdominal hypertension and abdominal compartment syndrome.

Intra-abdominal Hypertension as a Cause of Oliguric Acute Kidney Injury in a Patient with Chronic Lymphocytic Leukemia.

Acute kidney injury (AKI) is a well-known complication in patients with chronic lymphocytic leukemia (CLL). It could occur via diverse mechanisms such as leukemic infiltration, extrarenal obstruction, tumor lysis syndrome, glomerular diseases, and medication side effects. The incidence of kidney disease at the diagnosis of CLL is about 10%. We report a case of AKI, in a patient with a known history of CLL, due to abdominal compartment syndrome, caused by extremely enlarged intra-abdominal lymph masses. To the best of our knowledge, no case of AKI due to such cause has been reported so far.

Prevalence of intra-abdominal hypertension in horses with colic.

OBJECTIVE: To determine an abdominal pressure cutoff value for intra-abdominal hypertension (IAH) in the horse and characterize IAH in horses with acute colic. DESIGN: Prospective clinical cohort. SETTING: University teaching hospital. ANIMALS: Nine healthy adult horses and 56 horses with acute colic. INTERVENTIONS: Ventral intra-abdominal pressure (IAP) was measured in triplicate at end expiration and averaged. Each colic case was classified as medical or surgical and large intestine (LI) or small intestine (SI). Management and final outcome (alive, euthanized, or died) were recorded. IAH was defined as ≥32 mm Hg (mean + 2 SDs of ventral IAP in control horses). Proportions of horses with and without IAH for different lesions were expressed as fractions and percentages. Differences in IAP between groups were determined using ANOVA with post-testing or t-tests. Odds ratio for management strategy (ie, need for medical or surgical) in horses with IAH was performed using Fisher's exact test. P < 0.05 was considered significant. MEASUREMENTS AND MAIN RESULTS: IAP was higher in horses with colic compared to controls (P = 0.025). Over 18 months, 30.4% of horses with colic had IAH (n = 10 LI lesions, n = 7 SI lesions). Horses with LI medical lesions had the highest IAP of all lesions (mean 36.5 mm Hg). IAH horses with medical lesions were 15 times more likely to survive than IAH horses requiring surgery (P = 0.03). CONCLUSIONS: Acute colic in horses is associated with an increased ventral IAP compared with healthy controls. IAH does exist in horses with colic, notably LI medical lesions, and is associated with nonsurvival in horses that require surgery.

Intracranial Hypertension and Intra-abdominal Pressure. Is it Worth Measuring?

Patients with refractory intracranial hypertension who have already undergone all the measures recommended by the current guidelines can benefit from having their intraabdominal pressure monitored since its increase generates hemodynamic repercussions and secondary elevation of intracranial pressure. In this context, a bibliographic research was performed on PubMed with the terms intra-abdominal pressure, abdominal compartment syndrome, intracranial pressure, intracranial hypertension. Altogether, 146 articles were observed, 87 of which were from the year 2000, and only 15 articles were considered relevant to the topic. These studies indicate that patients with refractory intracranial hypertension can benefit fromthe measurement of intraabdominal pressure, since there is evidence that an increase in this pressure leads to organic dysfunctions with an indirect impact on cerebral venous return and, consequently, an increase in intracranial pressure. In thosewho underwent decompression laparotomy, direct effectswere observed in reducing intracranial hypertension and survival.

Effect of moderate elevated intra-abdominal pressure on lung mechanics and histological lung injury at different positive end-expiratory pressures.

INTRODUCTION: Intra-abdominal hypertension (IAH) is a well-known phenomenon in critically ill patients. Effects of a moderately elevated intra-abdominal pressure (IAP) on lung mechanics are still not fully analyzed. Moreover, the optimal positive end-expiratory pressure (PEEP) in elevated IAP is unclear. METHODS: We investigated changes in lung mechanics and transformation in histological lung patterns using three different PEEP levels in eighteen deeply anesthetized pigs with an IAP of 10 mmHg. After establishing the intra-abdominal pressure, we randomized the animals into 3 groups. Each of n = 6 (Group A = PEEP 5, B = PEEP 10 and C = PEEP 15 cmH2O). End-expiratory lung volume (EELV/kg body weight (bw)), pulmonary compliance (Cstat), driving pressure (ΔP) and transpulmonary pressure (ΔPL) were measured for 6 hours. Additionally, the histological lung injury score was calculated. RESULTS: Comparing hours 0 and 6 in group A, there was a decrease of EELV/kg (27±2 vs. 16±1 ml/kg; p<0.05) and of Cstat (42±2 vs. 27±1 ml/cmH2O; p<0.05) and an increase of ΔP (11±0 vs. 17±1 cmH2O; p<0.05) and ΔPL (6±0 vs. 10±1 cmH2O; p<0.05). In group B, there was no significant change in EELV/kg (27±3 vs. 24±3 ml/kg), but a decrease in Cstat (42±3 vs. 32±1 ml/cmH20; p<0.05) and an increase in ΔP (11±1 vs. 15±1 cmH2O; p<0.05) and ΔPL (5±1 vs. 7±0 cmH2O; p<0.05). In group C, there were no significant changes in EELV/kg (27±2 vs. 29±3 ml/kg), ΔP (10±1 vs. 12±1 cmH2O) and ΔPL (5±1 vs. 7±1 cmH2O), but a significant decrease of Cstat (43±1 vs. 37±1 ml/cmH2O; p<0.05). Histological lung injury score was lowest in group B. CONCLUSIONS: A moderate elevated IAP of 10 mmHg leads to relevant changes in lung mechanics during mechanical ventilation. In our study, a PEEP of 10 cmH2O was associated with a lower lung injury score and was able to overcome the IAP induced alterations of EELV.