Effect of isotonic versus hypotonic maintenance fluid therapy on urine output, fluid balance, and electrolyte homeostasis: a crossover study in fasting adult volunteers.

BACKGROUND.: Daily and globally, millions of adult hospitalized patients are exposed to maintenance i.v. fluid solutions supported by limited scientific evidence. In particular, it remains unclear whether fluid tonicity contributes to the recently established detrimental effects of fluid, sodium, and chloride overload. METHODS.: This crossover study consisted of two 48 h study periods, during which 12 fasting healthy adults were treated with a frequently prescribed solution (NaCl 0.9% in glucose 5% supplemented by 40 mmol litre -1 of potassium chloride) and a premixed hypotonic fluid (NaCl 0.32% in glucose 5% containing 26 mmol litre -1 of potassium) at a daily rate of 25 ml kg -1 of body weight. The primary end point was cumulative urine volume; fluid balance was thus calculated. We also explored the physiological mechanisms behind our findings and assessed electrolyte concentrations. RESULTS.: After 48 h, 595 ml (95% CI: 454-735) less urine was voided with isotonic fluids than hypotonic fluids ( P <0.001), or 803 ml (95% CI: 692-915) after excluding an outlier with 'exaggerated natriuresis of hypertension'. The isotonic treatment was characterized by a significant decrease in aldosterone ( P <0.001). Sodium concentrations were higher in the isotonic arm ( P <0.001), but all measurements remained within the normal range. Potassium concentrations did not differ between the two solutions ( P =0.45). Chloride concentrations were higher with the isotonic treatment ( P <0.001), even causing hyperchloraemia. CONCLUSIONS.: Even at maintenance rate, isotonic solutions caused lower urine output, characterized by decreased aldosterone concentrations indicating (unintentional) volume expansion, than hypotonic solutions and were associated with hyperchloraemia. Despite their lower sodium and potassium content, hypotonic fluids were not associated with hyponatraemia or hypokalaemia. CLINICAL TRIAL REGISTRATION.: ClinicalTrials.gov (NCT02822898) and EudraCT (2016-001846-24).

Core competencies in critical care for general medical practitioners in South Africa: A Delphi study.

Background: Despite a high burden of disease that requires critical care services, there are a limited number of intensivists in South Africa (SA). Medical practitioners at district and regional public sector hospitals frequently manage critically ill patients in the absence of intensivists, despite these medical practitioners having had minimal exposure to critical care during their undergraduate training. Objectives: To identify core competencies in critical care for medical practitioners who provide critical care services at public sector hospitals in SA where intensivists are not available to direct patient management. Methods: A preliminary list of core competencies in critical care was compiled. Thereafter, 13 national and international experts were requested to achieve consensus on a final list of core competencies that are required for critical care by medical practitioners, using a modified Delphi process. Results: A final list of 153 core competencies in critical care was identified. Conclusion: The core competencies identified by this study could assist in developing training programmes for medical practitioners to improve the quality of critical care services provided at district and regional hospitals in SA. Contribution of the study: The study provides consensus on a list of core competencies in critical care that non-intensivist medical practitioners managing critically ill patients in healthcare settings in South Africa, especially where intensivists are not readily available, should have. The list can form the core content of training programmes aimed at improving critical care competence of general medical practitioners, and in this way hopefully improve the overall outcomes of critically ill patients in South Africa.

Comparison of values in critically ill patients for global end-diastolic volume and extravascular lung water measured by transcardiopulmonary thermodilution: a meta-analysis of the literature.

INTRODUCTION: Hemodynamic parameters such as the global end-diastolic volume index (GEDVI) and extravascular lung water index (EVLWI), derived by transpulmonary thermodilution, have gained increasing interest for guiding fluid therapy in critically ill patients. The proposed normal values (680-800ml/m(2) for GEDVI and 3-7ml/kg for EVLWI) are based on measurements in healthy individuals and on expert opinion, and are assumed to be suitable for all patients. We analyzed the published data for GEDVI and EVLWI, and investigated the differences between a cohort of septic patients (SEP) and patients undergoing major surgery (SURG), respectively. METHODS: A PubMed literature search for GEDVI, EVLWI or transcardiopulmonary single/double indicator thermodilution was carried out, covering the period from 1990 to 2010. INTERVENTION: Meta-regression analysis was performed to identify any differences between the surgical (SURG) and non-surgical septic groups (SEP). RESULTS: Data from 1925 patients corresponding to 64 studies were included. On comparing both groups, mean GEDVI was significantly higher by 94ml/m(2) (95%CI: [54; 134]) in SEP compared to SURG patients (788ml/m(2) 95%CI: [762; 816], vs. 694ml/m(2), 95%CI: [678; 711], p<0.001). Mean EVLWI also differed significantly by 3.3ml/kg (95%CI: [1.4; 5.2], SURG 7.2ml/kg, 95%CI: [6.9; 7.6] vs. SEP 11.0ml/kg, 95%CI: [9.1; 13.0], p=0.001). CONCLUSIONS: The published data for GEDVI and EVLWI are heterogeneous, particularly in critically ill patients, and often exceed the proposed normal values derived from healthy individuals. In the group of septic patients, GEDVI and EVLWI were significantly higher than in the group of patients undergoing major surgery. This points to the need for defining different therapeutic targets for different patient populations.

The effect of fluid bolus administration on cerebral tissue oxygenation in post-cardiac arrest patients.

PURPOSE: Fluid boluses (FB) are often used in post-cardiac arrest (CA) patients with haemodynamic instability. Although FB may improve cardiac output (CO) and mean arterial pressure (MAP), FB may also increase central venous pressure (CVP), reduce arterial PaO2, dilute haemoglobin and cause interstitial oedema. The aim of the present study was to investigate the net effect of FB administration on cerebral tissue oxygenation saturation (SctO2) in post-CA patients. METHODS: Pre-planned sub-study of the Neuroprotect post-CA trial (NCT02541591). Patients with anticipated fluid responsiveness based on stroke volume variation (SVV) or passive leg raising test were administered a FB of 500 ml plasma-lyte A (Baxter Healthcare) and underwent pre- and post-FB assessments of stroke volume, CO, MAP, CVP, haemoglobin, PaO2 and SctO2. RESULTS: 52 patients (mean age 64 ±â€¯12 years, 75% male) received a total of 115 FB. Although administration of a FB resulted in a significant increase of stroke volume (63 ±â€¯22 vs 67 ±â€¯23 mL, p = 0.001), CO (4,2 ±â€¯1,6 vs 4,4 ±â€¯1,7 L/min, p = 0.001) and MAP (74,8 ±â€¯13,2 vs 79,2 ±â€¯12,9 mmHg, p = 0.004), it did not improve SctO2 (68.54 ±â€¯6.99 vs 68.70 ±â€¯6.80%, p = 0.49). Fluid bolus administration also resulted in a significant increase of CVP (10,0 ±â€¯4,5 vs 10,7 ±â€¯4,9 mmHg, p = 0.02), but did not affect PaO2 (99 ±â€¯31 vs 94 ±â€¯31 mmHg, p = 0.15) or haemoglobin concentrations (12,9 ±â€¯2,1 vs 12,8 ±â€¯2,2 g/dL, p = 0.10). In a multivariate model, FB-induced changes in CO (beta 0,77; p = 0.004) and in CVP (beta -0,23; p = 0.02) but not in MAP (beta 0,02; p = 0.18) predicted post-FB ΔSctO2. CONCLUSIONS: Despite improvements in CO and MAP, FB administration did not improve SctO2 in post-cardiac arrest patients.

Global and right ventricular end-diastolic volumes correlate better with preload after correction for ejection fraction.

BACKGROUND: Volumetric monitoring with right ventricular end-diastolic volume indexed (RVEDVi) and global end-diastolic volume indexed (GEDVi) is increasingly being suggested as a superior preload indicator compared with the filling pressures central venous pressure (CVP) or the pulmonary capillary wedge pressure (PCWP). However, static monitoring of these volumetric parameters has not consistently been shown to be able to predict changes in cardiac index (CI). The aim of this study was to evaluate whether a correction of RVEDVi and GEDVi with a measure of the individual contractile reserve, assessed by right ventricular ejection fraction (RVEF) and global ejection fraction, improves the ability of RVEDVi and GEDVi to monitor changes in preload over time in critically ill patients. METHODS: Hemodynamic measurements, both by pulmonary artery and by transcardiopulmonary thermodilution, were performed in 11 mechanically ventilated medical ICU patients. Correction of volumes was achieved by normalization to EF deviation from normal EF values in an exponential fashion. Data before and after fluid administration were obtained in eight patients, while data before and after diuretics were obtained in seven patients. RESULTS: No correlation was found between the change in cardiac filling pressures (DeltaCVP, DeltaPCWP) and DeltaCI (R(2) 0.01 and 0.00, respectively). Further, no correlation was found between DeltaRVEDVi or DeltaGEDVi and DeltaCI (R(2) 0.10 and 0.13, respectively). In contrast, a significant correlation was found between DeltaRVEDVi corrected to RVEF (DeltacRVEDVi) and DeltaCI (R(2) 0.64), as well as between DeltacGEDVi and DeltaCI (R(2) 0.59). An increase in the net fluid balance with +844 + or - 495 ml/m(2) resulted in a significant increase in CI of 0.5 + or - 0.3 l/min/m(2); however, only DeltacRVEDVi (R(2) 0.58) and DeltacGEDVi (R(2) 0.36) correlated significantly with DeltaCI. Administration of diuretics resulting in a net fluid balance of -942 + or - 658 ml/m(2) caused a significant decrease in CI with 0.7 + or - 0.5 l/min/m(2); however, only DeltacRVEDVi (R(2) 0.80) and DeltacGEDVi (R(2) 0.61) correlated significantly with DeltaCI. CONCLUSION: Correction of volumetric preload parameters by measures of ejection fraction improved the ability of these parameters to assess changes in preload over time in this heterogeneous group of critically ill patients.

Energy expenditure and caloric targets during continuous renal replacement therapy under regional citrate anticoagulation. A viewpoint.

BACKGROUND: Indirect calorimetry (IC) is the gold standard for measuring energy expenditure in critically ill patients However, continuous renal replacement therapy (CRRT) is a formal contraindication for IC use. AIMS: To discuss specific issues that hamper or preclude an IC-based assessment of energy expenditure and correct caloric prescription in CRRT-treated patients. METHODS: Narrative review of current literature. RESULTS: Several relevant pitfalls for validation of IC during CRRT were identified. First, IC measures CO2 production (VCO2) and O2 consumption to calculate resting energy expenditure (REE) with the Weir equation. VCO2 measurements are influenced by CRRT because CO2 is exchanged during the blood purification process. CO2 exchange also depends on type of pre- and/or postdilution fluid(s). CO2 dissolves in different forms with dynamic but unpredictable impact on VCO2. Second, the effect of immunologic activation and heat loss on REE caused by extracorporeal circulation during CRRT is poorly documented. Third, caloric prescription should be adapted to CRRT-induced in- and efflux of different nutrients. Finally, citrate, which is the preferred anticoagulant for CRRT, is a caloric source that may influence IC measurements and REE. CONCLUSION: Better understanding of CRRT-related processes is needed to assess REE and provide individualized nutritional therapy in this condition.

MECCIAS trial: Metabolic consequences of continuous veno-venous hemofiltration on indirect calorimetry.

BACKGROUND: and aims: Caloric prescription based on resting energy expenditure (REE) measured with indirect calorimetry (IC) improves outcome and is the gold standard in nutritional therapy of critically ill patients. Until now continuous renal replacement therapy (CRRT) precluded the use of IC due to several mechanisms. We investigated the impact of CRRT on V̇CO2, V̇O2 and REE to facilitate indirect calorimetry during CRRT. METHODS: In 10 critically ill ventilated patient in need of continuous veno-venous hemofiltration (CVVH) using citrate predilution we performed IC in 4 different states: baseline, high dose, baseline with NaCl predilution and without CVVH. CO2 content of effluent fluid was measured by a point of care blood gas analyzer. Carbon dioxide production (V̇CO2) measured with IC was adapted by adding the CO2 flow of effluent and deducing CO2 flow in postdilution fluid to calculate a true V̇CO2. True REE was calculated with the Weir equation using the true V̇CO2. RESULTS: CO2 removal in effluent during baseline, high dose and NaCl predilution was respectively 24 mL/min, 38 mL/min and 23 mL/min. Together with the CO2 delivery by the postdilution fluid this led to an adaptation of REE respectively by 34 kcal/d or 2% (p = 0,002), 44 kcal/d or 3% (p = 0,002) and 33 kcal/d or 2% (p = 0,002). Compared to the true REE during baseline of 1935 ± 921 kcal/d, true REE during high dose was 1723 ± 752 kcal/d (p = 0.65), during NaCl predilution it was 1604 ± 633 kcal/d (p = 0.014) and without CRRT it was 1713 ± 704 kcal/d (p = 0.193). CONCLUSIONS: CO2 alterations due to CVVH are clinically of no importance so no correction factor of REE is needed with or without CVVH. IC must be performed during CVVH as CVVH seems to alter metabolism. These changes may be mainly explained by the use of citrate predilution.

Mechanical Intestinal Obstruction in a Porcine Model: Effects of Intra-Abdominal Hypertension. A Preliminary Study.

INTRODUCTION: Mechanical intestinal obstruction is a disorder associated with intra-abdominal hypertension and abdominal compartment syndrome. As the large intestine intraluminal and intra-abdominal pressures are increased, so the patient's risk for intestinal ischaemia. Previous studies have focused on hypoperfusion and bacterial translocation without considering the concomitant effect of intra-abdominal hypertension. The objective of this study was to design and evaluate a mechanical intestinal obstruction model in pigs similar to the human pathophysiology. MATERIALS AND METHODS: Fifteen pigs were divided into three groups: a control group (n = 5) and two groups of 5 pigs with intra-abdominal hypertension induced by mechanical intestinal obstruction. The intra-abdominal pressures of 20 mmHg were maintained for 2 and 5 hours respectively. Hemodynamic, respiratory and gastric intramucosal pH values, as well as blood tests were recorded every 30 min. RESULTS: Significant differences between the control and mechanical intestinal obstruction groups were noted. The mean arterial pressure, cardiac index, dynamic pulmonary compliance and abdominal perfusion pressure decreased. The systemic vascular resistance index, central venous pressure, pulse pressure variation, airway resistance and lactate increased within 2 hours from starting intra-abdominal hypertension (p<0.05). In addition, we observed increased values for the peak and plateau airway pressures, and low values of gastric intramucosal pH in the mechanical intestinal obstruction groups that were significant after 3 hours. CONCLUSION: The mechanical intestinal obstruction model appears to adequately simulate the pathophysiology of intestinal obstruction that occurs in humans. Monitoring abdominal perfusion pressure, dynamic pulmonary compliance, gastric intramucosal pH and lactate values may provide insight in predicting the effects on endorgan function in patients with mechanical intestinal obstruction.

Acute renal failure due to bilateral lymphomatous infiltrates. Primary extranodal non-Hodgkin's lymphoma (p-EN-NHL) of the kidneys: does it really exist?

Primary extranodal non-Hodgkin's lymphoma (p-EN-NHL) of the kidneys with acute renal failure as the only manifestation is very rare. The origin of neoplastic lymphoid cells in the kidneys, organs normally free of lymphoid tissue, is an unsolved problem. A literature review over the last ten years revealed only 9 adult cases, including ours that match the usual criteria: (1) renal failure as the initial presentation, (2) bilateral enlargement of the kidneys without obstruction and other organ or nodal involvement, (3) diagnosis only made by renal biopsy, (4) absence of other causes of renal failure, and (5) rapid improvement of renal function after radiotherapy or, as in our case, systemic chemotherapy. Autopsy on two patients confirmed that p-EN-NHL of the kidneys without dissemination does exist as a separate entity.

Treatment of hepatitis B virus-related polyarteritis nodosa: two case reports and a review of the literature.

A substantial number of cases of polyarteritis nodosa (PAN) are related to hepatitis B virus (HBV) infection. Different treatment strategies are reported in the literature. The aim of this study was to review 15 years of literature (1988-2002) to determine the optimal treatment for HBV-related PAN at present, and to discuss the indications and mechanism of action of corticosteroids in HBV-related PAN, as many physicians are reluctant to use these in the presence of HBV infection. The first patient stopped his initial treatment, relapsed and died of cerebral infarction. The second case illustrates the favorable outcome with the standard treatment: corticosteroids, lamivudine and plasma exchanges. If adequate follow-up is possible, antiviral agents as well as corticosteroids are indicated in HBV-related PAN. Corticosteroids diminish inflammation and corticosteroid withdrawal induces an alanine aminotransferase (ALT) rebound in patients with a low baseline ALT level. Antiviral agents are essential, as they reduce the production of HBV antigens and help to achieve hepatitis B early antigen (HBeAg) seroconversion. Plasma exchanges reduce the level of circulating immune complexes and are included in the treatment protocol of all recent studies. However, their effect has not been evaluated in controlled trials. We concluded that if adequate follow-up is possible, antiviral agents as well as corticosteroids are indicated in HBV-related PAN.

Intranasal caffeine and amphetamine causing stroke.

A 37 year-old man with an ischaemic stroke after the nasal use of amphetamine and caffeine is reported. Transient arterial hypertension due to these agents may have been the mediator of the stroke. Mitral annular calcification was the only other abnormality found, and was thought not to play an important role in this patient. There was no evidence of a primary or secondary hypercoagulable state. Stroke due to nasal use of these agents appears not to have been previously reported (Medline literature search 1983-1993).

Filum terminale ependymoma revealed by acute cauda equina compression syndrome following intratumoral and spinal subarachnoid hemorrhage in a patient on oral anticoagulants.

A 65 year-old woman with a filum terminale ependymoma is reported, presenting with acute cauda equina compression syndrome due to intratumoural and subsequent spinal subarachnoid hemorrhage (SAH) following therapy with oral anticoagulants. Few cases of spinal ependymoma have been reported with an acute cauda equina compression syndrome as the initial and only symptom, and the unique feature of our patient's anticoagulant status has only been described once in this setting. Although intratumoural hemorrhage is very well known since the myxopapillary variant is unique to the cauda equina and consists of loose connective tissue and numerous small blood vessels that are prone to bleeding, spinal SAH is seldom seen and the different hypotheses about the pathophysiological mechanisms that might promote bleeding still remain unresolved and will be discussed in this paper, as well as the special clinical features of spinal SAH and some diagnostic and therapeutic implications. A review of the literature (Medline search 1983-1993) revealed only 13 cases, including ours, of spinal SAH due to cauda equina ependymoma, and the results of this review together with our findings are described in this paper.

Validation study of Nexfin® continuous non-invasive blood pressure monitoring in critically ill adult patients.

BACKGROUND: Nexfin® (BMEYE, Amsterdam, The Netherlands) is a totally non-invasive blood pressure and cardiac output (CO) monitor based on finger arterial pulse contour analysis. METHODS: We performed an open observational study in a mix of medical-surgical-burns critically ill patients (N.=45) to validate Nexfin obtained blood pressures (MAPnex) against PiCCO (MAPfem) derived blood pressure measurements. MAPnex, MAPfem and corresponding systolic (SBP) and diastolic (DBP) blood pressures were measured continuously and registered with a 2 hour interval during the 8-hour study period. Statistical analysis was performed by Pearson regression, Bland and Altman, Concordance plot and Polar plot analysis. RESULTS: MAPnex shows excellent correlation with MAPfem (R² 0.88, mean bias ± LA -2.3±12.4 mmHg, 14.7% error) and may be used interchangeably with invasive monitoring. The excellent MAPnex -MAPfem correlation was preserved in subgroup analysis for patients with severe hypotension, high systemic vascular resistance, low CO, hypothermia and in patients supported by inotropic/vasopressive agents. MAPnex is able to follow changes in MAPfem during the same time interval (level of concordance 85.5%). Nexfin SBP and DBP show significant correlation with PiCCO but the criteria for interchangeability were not met. Finally, polar plot analysis showed that trending capabilities were excellent when changes in MAPnex (ΔMAPnex) were compared to ΔMAPfem (96.1% of changes were within the level of 10% limits of agreement). CONCLUSION: In this sample of critically ill patients we found a good correlation between MAPnex and invasive blood pressures obtained by PiCCO.

A systematic review and individual patient data meta-analysis on intra-abdominal hypertension in critically ill patients: the wake-up project. World initiative on Abdominal Hypertension Epidemiology, a Unifying Project (WAKE-Up!).

Intra-abdominal hypertension (IAH), defined as a pathologically increase in intraabdominal pressure, is commonly found in critically ill patients. While IAH has been associated with several abdominal as well as extra-abdominal conditions, few studies have examined the occurrence of IAH in relation to mortality. The aim of this paper was to evaluate the prognostic role of IAH and its risk factors at admission in critically ill patients across a wide range of settings and countries. An individual patient meta-analysis of all available data and a systematic review of published (in full or as abstract) medical databases and studies between 1996 and June 2012 were performed. The search was limited to "clinical trials" and "randomized controlled trials", "adults", using the terms "intra-abdominal pressure", "intraabdominal hypertension" combined with any of the terms "outcome" and "mortality". All together data on 2707 patients, representing 21 centers from 11 countries was obtained. Data on 1038 patients were not analysed because of the following exclusion criteria: no IAP value on admission (N.=712), absence of information on ICU outcome (N.=195), age <18 or >95 years (N.=131). Data from 1669 individual patients (19 centers from 9 countries) were analyzed in the meta-analysis. Presence of IAH was defined as a sustained increase in IAP equal to or above 12 mmHg. At admission the mean overall IAP was 9.9±5.0 mmHg, with 463 patients (27.7%) presenting IAH with a mean IAP of 16.3±3.4 mmHg. The only independent predictors for IAH were SOFA score and fluid balance on the day of admission. Five hundred thirteen patients (30.8%) died in intensive care. The independent predictors for intensive care mortality were IAH, SAPS II score, SOFA score and admission category. This systematic review and individual patient data meta-analysis shows that IAH is frequently present in critically ill patients and it is an independent predictor for mortality.

A Systematic Review And Individual Patient Data Meta-Analysis On Intraabdominal Hypertension In Critically Ill Patients: The Wake-Up Project World Initiative on Abdominal Hypertension Epidemiology, a Unifying Project (WAKE-Up!).

Background: Intraabdominal hypertension (IAH), defined as a pathologically increase in intraabdominal pressure, is commonly found in critically ill patients. While IAH has been associated with several abdominal as well as extra-abdominal conditions, few studies have examined the occurrence of IAH in relation to mortality. Objective: To evaluate the prognostic role of IAH and its risk factors at admission in critically ill patients across a wide range of settings and countries. Data sources: An individual patient meta-analysis of all available data and a systematic review of published (in full or as abstract) medical databases and studies between 1996 and June 2012 were performed. The search was limited to "clinical trials" and "randomized controlled trials", "adults", using the terms "intraabdominal pressure", "intraabdominal hypertension" combined with any of the terms "outcome" and "mortality". All together data on 2707 patients, representing 21 centers from 11 countries was obtained. Data on 1038 patients were not analysed because of the following exclusion criteria: no IAP value on admission (n=712), absence of information on ICU outcome (n=195), age <18 or > 95 years (n=131). Results: Data from 1669 individual patients (19 centers from 9 countries) were analyzed in the meta-analysis. Presence of IAH was defined as a sustained increase in IAP equal to or above 12 mmHg. At admission the mean overall IAP was 9.9±5.0 mmHg, with 463 patients (27.7%) presenting IAH with a mean IAP of 16.3±3.4 mmHg. The only independent predictors for IAH were SOFA score and fluid balance on the day of admission. Five hundred thirteen patients (30.8%) died in intensive care. The independent predictors for intensive care mortality were IAH, SAPS II score, SOFA score and admission category. Conclusions: This systematic review and individual patient data meta-analysis shows that IAH is frequently present in critically ill patients and it is an independent predictor for mortality.

Localised abdominal compartment syndrome: bladder-over-gastric pressure ratio (B/G ratio) as a clue to diagnosis.

INTRODUCTION: Intra-abdominal hypertension (IAH) and abdominal compartment syndrome (ACS) have been identified as a cause of organ dysfunction and mortality in critically ill patients. The diagnosis of IAH/ACS depends on accurate intra-abdominal pressure (IAP) measurement, which is usually performed via the bladder or the stomach.The aim of this study was to describe cases where intragastric pressure (IGP) and intrabladder pressure (IBP) were measured simultaneously. PATIENTS AND METHODS: After review of medical records, four patients admitted to our ICU department where both IGP and IBP were measured, could be identified. IGP was measured using the Spiegelberg catheter and IBP was measured using the FoleyManometer LV. In all patients, the bladder-over-gastric pressure ratio (B/G ratio) was calculated. RESULTS: In two of four patients, IGP and IBP differed significantly. In one patient the B/G ratio was lower than 1 suggesting a diagnosis of epigastric ACS and in one patient B/G ratio was greater than 1 leading to a diagnosis of pelvic ACS. The latter patient was spared a decompressive laparotomy due to the additional IGP measurement and the subsequent diagnosis of localized ACS. CONCLUSION: The preferred methods for IAP measurement are via the bladder and via the stomach. In some patients, IGP and IBP may differ significantly and this may have clinical implications. Clinicians should be aware of the possibility of localized ACS. In order to identify risk factors and to recommend treatment for localized ACS, further study of simultaneous IGP and IBP measurements are needed.