Comparison of Bioelectrical Impedance Analysis (BIA)-Derived Parameters in Healthy Volunteers and Critically Ill Patients.

OBJECTIVE: To compare bioelectrical impedance analysis (BIA)-derived parameters in healthy volunteers and critically ill patients and to assess its prognostic value in an ICU patient cohort. DESIGN: Retrospective, observational data analysis. SETTING: Single centre, tertiary-level ICU (Ziekenhuis Netwerk Antwerpen, ZNA Stuivenberg Hospital). PATIENTS: 101 patients and 101 healthy subjects, participants of International Fluid Academy Days. MEASUREMENTS AND MAIN RESULTS: Compared to healthy volunteers, both male and female ICU patients had significantly higher values for total body water (TBW), extracellular water (ECW), extracellular fluid (ECF), plasma, and interstitial fluid volumes. The phase angle was significantly lower and the malnutrition index was significantly higher in ICU patients, regardless of gender. Non-survivors in the ICU had significantly higher extracellular water content (ECW, 50.7 ± 5.1 vs. 48.9 ± 4.3%, p = 0.047) and accordingly significantly lower intracellular water (ICW, 49.2 ± 5.1 vs. 51.1 ± 4.3%, p = 0.047). The malnutrition index was also significantly higher in non-survivors compared to survivors (0.94 ± 0.17 vs. 0.87 ± 0.16, p = 0.048), as was the capillary leak index (ECW/ICW). CONCLUSIONS: Compared to healthy volunteers, this study observed a higher malnutrition index and TBW in ICU patients with an accumulation of fluids in the extracellular compartment. ICU non-survivors showed similar results, indicating that ICU patients and a fortiori non-survivors are generally overhydrated, with increased TBW and ECW, and more undernourished, as indicated by a higher malnutrition index.

Prognostic value of bioelectrical impedance analysis for assessment of fluid overload in ICU patients: a pilot study.

INTRODUCTION: The non-invasive analysis of body fluid composition with bio-electrical impedance analysis (BIA) provides additional information allowing for more persona-lised therapy to improve outcomes. The aim of this study is to assess the prognostic value of fluid overload (FO) in the first week of intensive care unit (ICU) stay. MATERIAL AND METHODS: A retrospective, observational analysis of 101 ICU patients. Whole-body BIA measurements were performed, and FO was defined as a 5% increase in volume excess from baseline body weight. RESULTS: Baseline demographic data, including severity scores, were similar in both the fluid overload-positive (FO+, n = 49) patients and in patients without fluid overload (FO-, n = 52). Patients with FO+ had significantly higher cumulative fluid balance during their ICU stay compared to those without FO (8.8 ± 7.0 vs. 5.5 ± 5.4 litres; P = 0.009), VE (9.9 ± 6.5 vs. 1.5 ± 1.5 litres; P < 0.001), total body water (63.0 ± 9.5 vs. 52.8 ± 8.1%; P < 0.001), and extracellular water (27.0 ± 7.3 vs. 19.6 ± 3.7 litres; P < 0.001). The presence of 5%, 7.5%, and 10% fluid overload was directly associated with increased ICU mortality rates. The percentage fluid overload (P = 0.039) was an independent predictor for hospital mortality. CONCLUSIONS: A higher mortality rate in ICU-patients with FO was observed. FO is an independent prognostic factor because neither APACHE-II, SOFA, nor SAPS-II significantly differed on admission between survivors and non-survivors. Further research is needed to confirm these data prospectively and to evaluate whether BIA-guided deresuscitation in the subacute phase will improve mortality rates.

Acute primary abdominal compartment syndrome due to Clostridium difficile induced toxic megacolon: a case report and review of the literature.

BACKGROUND: Without timely diagnosis, acute primary abdominal compartment syndrome (ACS) is a potentially fatal syndrome and often goes unrecognized until severe symptoms appear. Early diagnosis may significantly improve the prognosis of these patients. CASE PRESENTATION: We present the case of a 54-year-old man, successfully treated for acute myeloid leukemia with cytosine arabinoside, admitted to the intensive care unit with severe shock, refractory to standard therapy with antibiotics, fluid resuscitation, and vasopressors. Early diagnosis of acute primary abdominal syndrome was made based on an intra-abdominal pressure of 20 mm Hg (3 kPa) with new onset organ failure, after which decompressive laparotomy was performed. Stool cultures grew Clostridium difficile. Despite abdominal decompression, the abdominal compartment syndrome persisted with the development of toxic megacolon and a total colectomy was performed with favorable evolution. METHODS: A systematic review of published case reports was performed describing a primary ACS due to C. difficile toxic megacolon. A PubMed database search was performed with the following search terms, single or in combination: 'clostridium difficile', 'toxic megacolon', 'abdominal compartment syndrome', and 'CDI'. The latest search was performed for March 2019; only case reports after 1998 were included. RESULTS: We found a total of 19 case reports with C. difficile toxic megacolon (including the present case). The male/female ratio was 12/7, and there were 3 children. The mean age was 48.7 ± 23.5 years. The reason for admission was sepsis in 6, trauma in 2, postoperative in 4, enterocolitis in 5, pregnancy in 1 and abdominal complaints after topical antibiotics in 1. Three patients did not develop diarrhea. Five patients presented with diarrhea on average 5.8 ± 5.1 (median 4, 1-14) days prior to hospital admission while 7 patients developed diarrhea on average after 10 ± 19.6 (median 3, 0-54) days during admission. The intra-abdominal pressure (measured in 6 patients, including ours) was 29.2 ± 11 (20-50) mm Hg (3-7 kPa). Treatment consisted of (a combination of) vancomycin (orally or via rectal enemas), metronidazole (orally or intravenously), and surgical intervention (with decompressive laparotomy). Three patients died (15.8%). CONCLUSIONS: Monitoring of intra-abdominal pressure allows early detection of abdominal compartment syndrome and is warranted in patients with C. difficile infection and/or toxic megacolon. Early decompression can lead to improved outcomes in patients with severe shock and organ failure.

Incidence and prognosis of intra-abdominal hypertension and abdominal compartment syndrome in severely burned patients: Pilot study and review of the literature.

BACKGROUND: Burn patients are at high risk for secondary intra-abdominal hypertension (IAH) and abdominal compartment syndrome (ACS) due to capillary leak and large volume fluid resuscitation. Our objective was to examine the incidence the incidence of IAH and ACS and their relation to outcome in mechanically ventilated (MV) burn patients. METHODS: This observational study included all MV burn patients admitted between April 2007 and December 2009. Various physiological parameters, intra-abdominal pressure (IAP) measurements and severity scoring indices were recorded on admission and/or each day in ICU. Transpulmonary thermodilution parameters were also obtained in 23 patients. The mean and maximum IAP during admission was calculated. The primary endpoint was ICU (burn unit) mortality. RESULTS: Fifty-six patients were included. The average Simplified Acute Physiology Score (SAPS II) and Sequential Organ Failure Assessment (SOFA) scores were 43.4 (± 15.1) and 6.4 (± 3.4), respectively. The average total body surface area (TBSA) affected by burns was 24.9% (± 24.9), with 33 patients suffering inhalational injuries. Forty-four (78.6%) patients developed IAH and 16 (28.6%) suffered ACS. Patients with ACS had higher TBSAs burned (35.8 ± 30 vs. 20.6 ± 21.4%, P = 0.04) and higher cumulative fluid balances after 48 hours (13.6 ± 16L vs. 7.6 ± 4.1 L, P = 0.03). The TBSA burned correlated well with the mean IAP (R = 0.34, P = 0.01). Mortality was notably high (26.8%) and significantly higher in patients with IAH (34.1%, P = 0.014) and ACS (62.5%, P < 0.0001). Most patients received more fluids than calculated by the Parkland Consensus Formula while, interestingly, non-survivors received less. However, when patients with pure inhalation injury were excluded there were no differences. Non-surgical interventions (n = 24) were successful in removing body fluids and were related to a significant decrease in IAP, central venous pressure (CVP) and an improvement in oxygenation and urine output. Non-resolution of IAH was associated with a significantly worse outcome (P < 0.0001). CONCLUSION: Based on our preliminary results we conclude that IAH and ACS have a relatively high incidence in MV burn patients compared to other groups of critically ill patients. The percentage of TBSA burned correlates with the mean IAP. The combination of high CLI, positive (daily and cumulative) fluid balance, high IAP, high EVLWI and low APP suggest a poor outcome. Non-surgical interventions appear to improve end-organ function. Non-resolution of IAH is related to a worse outcome.

Common pitfalls and tips and tricks to get the most out of your transpulmonary thermodilution device: results of a survey and state-of-the-art review.

BACKGROUND: Haemodynamic monitoring with transpulmonary thermodilution (TPTD) is less invasive than a pulmonary artery catheter, and is increasingly used in the Intensive Care Unit and the Operating Room. Optimal treatment of the critically ill patient demands adequate, precise and continuous monitoring of clinical parameters. Little is known about staff knowledge of the basic principles and practical implementation of TPTD measurements at the bedside. The aims of this review are to: 1) present the results of a survey on the knowledge of TPTD measurement among 252 nurses and doctors; and 2) to focus on specific situations and common pitfalls in order to improve patient management in daily practice. METHODS: Web-based survey on knowledge of PiCCO technology (Pulsion Medical Systems, Feldkirchen, Germany), followed by PubMed and Medline search with review of the relevant literature regarding the use of TPTD in specific situations. RESULTS: In total, 252 persons participated in the survey: 196 nurses (78%) and 56 medical doctors (22%) of whom 17 were residents in training. Knowledge on the use of TPTD appears to be suboptimal, with an average score of 58.3%. Doctors performed better than nurses (62.7% vs 57.0%, P = 0.012). About 190 out of 252 (75.4%) scored at least 50% but only 45 respondents (17.9%) obtained a score of 70% or more. Having five years of PiCCO experience was present in 15.8% of the participants and this was correlated to passing the test, defined as obtaining a test result of ≥ 50% (P = 0.07) or obtaining a test result of ≥ 70% (P = 0.05). There were no other parameters significantly predictive for obtaining a result above 50% or above 70% such as gender or doctor versus nurse or Belgian versus Dutch residency, or years of ICU experience. High quality education of nursing and medical staff is necessary to perform the technique correctly and to analyse and interpret the information that can be obtained. Visual inspection of thermodilution curves is important as this can point towards specific pathology. Interpretation of the parameters that can be obtained with TPTD in specific conditions is discussed. Finally, a practical approach is given in ten easy steps for nurses and doctors. CONCLUSION: TPTD has gained its place in the haemodynamic monitoring field, but, as with any technique, its virtue is only fully appreciated with correct use and interpretation.

Validation of a novel method for measuring intra-abdominal pressure and gastric residual volume in critically ill patients.

BACKGROUND: Gastric residual volume (GRV) can be measured in a variety of ways in critically ill patients, most often, the nasogastric tube is disconnected and the GRV is aspirated via a 60 mL syringe. Bladder pressure (IBP) measurement is the gold standard for intra-abdominal pressure (IAP) estimation. This study will look at the validation of a novel method combining measurement of GRV and estimation of IAP via intra-gastric pressure (IGP). METHODS: In total 135 paired IAP and 146 paired GRV measurements were performed in 37 mechanically ventilated ICU patients. The IAP was estimated via the bladder (i.e. IBP) using the FoleyManometer and via the stomach (i.e. IGP) with the new device. The GRV was measured with the new device (GRVprototype) and via the classic method (GRVclassic). The devices were provided by Holtech Medical (Charlottenlund, Denmark) and data were retrospectively analysed. RESULTS: The number of paired measurements in each patient was 4 ± 1. The mean IBP was 10.7 ± 4.1 and mean IGP was 11.6 ± 4.1 mm Hg. Correlation between the IBP and IGP was significant, however moderate (R2 = 0.51). Analysis according to Bland and Altman showed a bias and precision of 0.8 and 2.7 mm Hg respectively, however the limits of agreement (LA) were large and ranged from -4.5 to 6.1 mm Hg. Changes in IGP correlated well with changes in IBP. The median GRVprototype was 80 mL (0-1050) and equal to the median GRVclassic of 80 mL (0-1250). Correlation between the 2 methods was excellent (R2 = 0.89). Analysis according to Bland and Altman showed a bias and precision of -0.8 and 52.3 mL respectively and the LA ranged from -103 to 102 mL. Changes in GRVclassic correlated well with changes in GRVprototype. CONCLUSIONS: The results of this multicentre pilot study show that GRV can be measured with the new device. Furthermore this allows simultaneous screening for intra-abdominal hypertension with IAP estimation via IGP.

Prognostic value of serum galactomannan in mixed ICU patients: a retrospective observational study.

BACKGROUND: Little is known about serum galactomannan (GM) testing in (mostly non-neutropenic) mixed intensive care unit (ICU) patients. The aim of this study was to look for the incidence of invasive aspergillosis (IA) in critically ill patients, to validate previously reported GM thresholds, and to evaluate the prognostic value of GM. METHODS: This was a retrospective study of 474 GM samples in 160 patients from the start of January 2003 until the start of February 2004. GM tests were ordered because of a clinical suspicion of IA or on a regular basis in immune compromised patients. The number of samples per patient was 3 ± 2.6. We used the criteria of the European Organisation for Research and Treatment of Cancer (EORTC) to define proven IA, probable IA, and possible IA. The number of positive samples, with GM optical density (OD) > 0.5 was 230 (48.5%). RESULTS: In our study population, five (3%) patients had proven IA, 11 (7%) had probable, 27 (17.5%) had possible, and 116 (72.5%) had no IA. We could not identify a GM threshold for IA with analysis of receiver operating characteristics (ROC) curves: with a sensitivity of (56.3%, 50%, 50%, 37.5%), specificity (38.2%, 67.5%, 68.8%, 72.9%), NPV (88.7%, 91.8%, 92.5%, 91.3%) and PPV (9.2%, 12.9%, 15.1%, 13.3%) for a cut-off of OD > 0.5, > 0.8, > 1.1 and > 1.5 respectively. IA was associated with high mortality of 87.5% and 100% in patients with probable and proven IA respectively. Patients with IA had a significant increase of GM during their stay (GMdelta 0.7 ± 1.5 vs -0.2 ± 1.5, P = 0.027). The overall ICU mortality was 41.9% and the hospital mortality was 58.1%. Patients who died in the ICU and in the hospital had higher APACHE- -II, SAPS-II and SOFA scores (P < 0.0001) and also a significant increase in GM during their stay with 0.27 ± 1.26 (ICU non-survivors) and 0.11 ± 1.55 (hospital non-survivors) compared to a decrease in GM -0.43 ± 1.7 (P = 0.004) and -0.48 ± 1.51 (P = 0.017) in ICU and hospital survivors respectively. Non-survivors also had higher mean GM values but this was not statistically significant. There was a trend towards higher GM values in patients treated with piperacillin/tazobactam (n = 34), but this did not reach statistical significance. Neutropenic patients (n = 31) showed an increase in GM during their stay 0.32 ± 1.3 vs a decrease with -0.43 ± 1.7 in non-neutropenic patients (P = 0.07). Patients on total parenteral nutrition (n = 125) had higher maximal GM levels (1.55 ± 1.94 vs 0.88 ± 1.25, P = 0.058). Patients who were mechanically ventilated had significantly higher mean (P = 0.038) and maximal (P = 0.007) GM levels. CONCLUSIONS: We found a high incidence of proven and probable IA in a group of mixed ICU patients (10%) and the presence of IA was associated with a high mortality. The serum GM antigen detection test may not be useful in the diagnosis of IA in mixed ICU patients, according to the results of the ROC analysis. We could not define a useful threshold.

Nexfin noninvasive continuous hemodynamic monitoring: validation against continuous pulse contour and intermittent transpulmonary thermodilution derived cardiac output in critically ill patients.

INTRODUCTION: Nexfin (Bmeye, Amsterdam, Netherlands) is a noninvasive cardiac output (CO) monitor based on finger arterial pulse contour analysis. The aim of this study was to validate Nexfin CO (NexCO) against thermodilution (TDCO) and pulse contour CO (CCO) by PiCCO (Pulsion Medical Systems, Munich, Germany). PATIENTS AND METHODS: In a mix of critically ill patients (n = 45), NexCO and CCO were measured continuously and recorded at 2-hour intervals during the 8-hour study period. TDCO was measured at 0-4-8 hrs. RESULTS: NexCO showed a moderate to good (significant) correlation with TDCO (R (2) 0.68, P < 0.001) and CCO (R (2) 0.71, P < 0.001). Bland and Altman analysis comparing NexCO with TDCO revealed a bias (± limits of agreement, LA) of 0.4 ± 2.32 L/min (with 36% error) while analysis comparing NexCO with CCO showed a bias (±LA) of 0.2 ± 2.32 L/min (37% error). NexCO is able to follow changes in TDCO and CCO during the same time interval (level of concordance 89.3% and 81%). Finally, polar plot analysis showed that trending capabilities were acceptable when changes in NexCO (ΔNexCO) were compared to ΔTDCO and ΔCCO (resp., 89% and 88.9% of changes were within the level of 10% limits of agreement). CONCLUSION: we found a moderate to good correlation between CO measurements obtained with Nexfin and PiCCO.

Fluid management in critically ill patients: the role of extravascular lung water, abdominal hypertension, capillary leak, and fluid balance.

INTRODUCTION: Capillary leak in critically ill patients leads to interstitial edema. Fluid overload is independently associated with poor prognosis. Bedside measurement of intra-abdominal pressure (IAP), extravascular lung water index (EVLWI), fluid balance, and capillary leak index (CLI) may provide a valuable prognostic tool in mechanically ventilated patients. METHODS: We performed an observational study of 123 mechanically ventilated patients with extended hemodynamic monitoring, analyzing process-of-care variables for the first week of ICU admission. The primary outcome parameter was 28-day mortality. ΔmaxEVLWI indicated the maximum difference between EVLWI measurements during ICU stay. Patients with a ΔmaxEVLWI <-2 mL/kg were called 'responders'. CLI was defined as C-reactive protein (milligrams per deciliter) over albumin (grams per liter) ratio and conservative late fluid management (CLFM) as even-to-negative fluid balance on at least two consecutive days. RESULTS: CLI had a biphasic course. ΔmaxEVLWI was lower if CLFM was achieved and in survivors (-2.4 ± 4.8 vs 1.0 ± 5.5 mL/kg, p = 0.001; -3.3 ± 3.8 vs 2.5 ± 5.3 mL/kg, p = 0.001, respectively). No CLFM achievement was associated with increased CLI and IAPmean on day 3 and higher risk to be nonresponder (odds ratio (OR) 2.76, p = 0.046; OR 1.28, p = 0.011; OR 5.52, p = 0.001, respectively). Responders had more ventilator-free days during the first week (2.5 ± 2.3 vs 1.5 ± 2.3, p = 0.023). Not achieving CLFM and being nonresponder were strong independent predictors of mortality (OR 9.34, p = 0.001 and OR 7.14, p = 0.001, respectively). CONCLUSION: There seems to be an important correlation between CLI, EVLWI kinetics, IAP, and fluid balance in mechanically ventilated patients, associated with organ dysfunction and poor prognosis. In this context, we introduce the global increased permeability syndrome.

Intra-abdominal pressure measurement using the FoleyManometer does not increase the risk for urinary tract infection in critically ill patients.

OBJECTIVE: The aim of this study was to determine whether intra-abdominal pressure (IAP) monitoring using the FoleyManometer (Holtech Medical, Charlottenlund, Denmark) increases the risk of urinary tract infection (UTI). DESIGN: A retrospective database review was conducted. SETTING: The study was conducted in the 12-bed medical intensive care unit of ZNA Stuivenberg Hospital (Antwerp, Belgium), a tertiary hospital. PATIENTS: There were 5,890 patients admitted to the medical intensive care unit of which 1,097 patients underwent intrabladder pressure (IBP) monitoring as estimate for IAP. INTERVENTIONS: Crude and adjusted UTI rates were compared among patients undergoing IAP measurements with three different intrabladder methods: a modified homemade technique, a FoleyManometer with 35 ml reservoir, and a FoleyManometer low volume (FoleyManometerLV) with less than 10 ml priming volume. MEASUREMENTS AND RESULTS: Four consecutive time periods of 24 months were defined and compared with regard to IAP measurement: period 1 (2000-2001), during which IAP monitoring was not used routinely (which serves as a control group), was compared with period 2 (2002-2003), using a modified homemade technique; period 3 (2004-2005), introducing the FoleyManometer; and finally period 4 (2006-2007), in which the FoleyManometerLV was introduced. The incidence of IBP measurements increased from 1.4% in period 1 to 45.4% in period 4 (p < 0.001). At the same time, the Simplified Acute Physiology Score (version 2) (SAPS-II) increased significantly from 24.4 ± 21.5 to 34.9 ± 18.7 (p < 0.001) together with the percentage of ventilated patients from 18.6% to 40.7% (p < 0.001). In total, 1,097 patients had IAP measurements via the bladder. The UTI rates were adjusted for disease severity by multiplying each crude rate with the ratio of control versus study patient SAPS-II probability of mortality. Crude and adjusted UTI rates per 1,000 catheter days (CD) were on average 16.1 and 12.8/1,000 CD, respectively, and were not significantly different between the four time periods. CONCLUSIONS: Intrabladder pressure monitoring as estimate for IAP either via a closed transducer technique or the closed FoleyManometer technique seems safe and does not alter the risk of UTI in critically ill patients.

Aiming for a negative fluid balance in patients with acute lung injury and increased intra-abdominal pressure: a pilot study looking at the effects of PAL-treatment.

INTRODUCTION: Achievement of a negative fluid balance in patients with capillary leak is associated with improved outcome. We investigated the effects of a multi-modal restrictive fluid strategy aiming for negative fluid balance in patients with acute lung injury (ALI). METHODS: In this retrospective matched case-control study, we included 114 mechanically ventilated (MV) patients with ALI. We compared outcomes between a group of 57 patients receiving PAL-treatment (PAL group) and a matched control group, abstracted from a historical cohort. PAL-treatment combines high levels of positive end-expiratory pressure, small volume resuscitation with hyperoncotic albumin, and fluid removal with furosemide (Lasix®) or ultrafiltration. Effects on extravascular lung water index (EVLWI), intra-abdominal pressure (IAP), organ function, and vasopressor therapy were recorded during 1 week. The primary outcome parameter was 28-day mortality. RESULTS: At baseline, no significant intergroup differences were found, except for lower PaO2/FIO2 and increased IAP in the PAL group (174.5 ± 84.5 vs 256.5 ± 152.7, p = 0.001; 10.0 ± 4.2 vs 8.0 ± 3.7 mmHg, p = 0.013, respectively). After 1 week, PAL-treated patients had a greater reduction of EVLWI, IAP, and cumulative fluid balance (-4.2 ± 5.6 vs -1.1 ± 3.7 mL/kg, p = 0.006; -0.4 ± 3.6 vs 1.8 ± 3.8 mmHg, p = 0.007; -1,451 ± 7,761 vs 8,027 ± 5,254 mL, p < 0.001). Repercussions on cardiovascular and renal function were limited. PAL-treated patients required fewer days of intensive care unit admission and days on MV (23.6 ± 15 vs 37.1 ± 19.9 days, p = 0.006; 14.6 ± 10.7 vs 25.5 ± 20.2 days, respectively) and had a lower 28-day mortality (28.1% vs 49.1%, p = 0.034). CONCLUSION: PAL-treatment in patients with ALI is associated with a negative fluid balance, a reduction of EVLWI and IAP, and improved clinical outcomes without compromising organ function.

Relationship between intra-abdominal pressure and indocyanine green plasma disappearance rate: hepatic perfusion may be impaired in critically ill patients with intra-abdominal hypertension.

BACKGROUND: Monitoring hepatic blood flow and function might be crucial in treating critically ill patients. Intra-abdominal hypertension is associated with decreased abdominal blood flow, organ dysfunction, and increased mortality. The plasma disappearance rate (PDR) of indocyanine green (ICG) is considered to be a compound marker for hepatosplanchnic perfusion and hepatocellular membrane transport and correlates well with survival in critically ill patients. However, correlation between PDRICG and intra-abdominal pressure (IAP) remains poorly understood. The aim of this retrospective study was to investigate the correlation between PDRICG and classic liver laboratory parameters, IAP and abdominal perfusion pressure (APP). The secondary goal was to evaluate IAP, APP, and PDRICG as prognostic factors for mortality. METHODS: A total of 182 paired IAP and PDRICG measurements were performed in 40 critically ill patients. The mean values per patient were used for comparison. The IAP was measured using either a balloon-tipped stomach catheter connected to an IAP monitor (Spiegelberg, Hamburg, Germany, or CiMON, Pulsion Medical Systems, Munich, Germany) or a bladder FoleyManometer (Holtech Medical, Charlottenlund, Denmark). PDRICG was measured at the bedside using the LiMON device (Pulsion Medical Systems, Munich, Germany). Primary endpoint was hospital mortality. RESULTS: There was no significant correlation between PDRICG and classic liver laboratory parameters, but PDRICG did correlate significantly with APP (R = 0.62) and was inversely correlated with IAP (R = -0.52). Changes in PDRICG were associated with significant concomitant changes in APP (R = 0.73) and opposite changes in IAP (R = 0.61). The IAP was significantly higher (14.6 ± 4.6 vs. 11.1 ± 5.3 mmHg, p = 0.03), and PDRICG (10 ± 8.3 vs. 15.9 ± 5.2%, p = 0.02) and APP (43.6 ± 9 vs. 57.9 ± 12.2 mmHg, p < 0.0001) were significantly lower in non-survivors. CONCLUSIONS: PDRICG is positively correlated to APP and inversely correlated to IAP. Changes in APP are associated with significant concomitant changes in PDRICG, while changes in IAP are associated with opposite changes in PDRICG, suggesting that an increase in IAP may compromise hepatosplanchnic perfusion. Both PDRICG and IAP are correlated with outcome. Measurement of PDRICG may be a useful additional clinical tool to assess the negative effects of increased IAP on liver perfusion and function.

Renal replacement therapy with net fluid removal lowers intra-abdominal pressure and volumetric indices in critically ill patients.

BACKGROUND: Little is known about the effects of renal replacement therapy (RRT) with fluid removal on intra-abdominal pressure (IAP). The global end-diastolic volume index (GEDVI) and extravascular lung water index (EVLWI) can easily be measured bedside by transpulmonary thermodilution (TPTD). The aim of this study is to evaluate the changes in IAP, GEDVI and EVLWI in critically ill patients receiving slow extended daily dialysis (SLEDD) or continuous venovenous haemofiltration (CVVH) with the intention of net fluid removal. METHODS: We performed a retrospective cohort study in ICU patients who were treated with SLEDD or CVVH and in whom IAP was also measured, and RRT sessions were excluded when the dose of vasoactive medication needed to be changed between the pre- and post-dialysis TPTD measurements and when net fluid loss did not exceed 500 ml. The TPTD measurements were performed within 2 h before and after SLEDD; in case of CVVH, before and after an interval of 12 h. RESULTS: We studied 25 consecutive dialysis sessions in nine patients with acute renal failure and cardiogenic or non-cardiogenic pulmonary oedema. The GEDVI and EVLWI values before dialysis were 877 ml/m² and 14 ml/kg, respectively. Average net ultrafiltration per session was 3.6 l, with a net fluid loss 1.9 l. The GEDVI decreased significantly during dialysis, but not more than 47.8 ml/m² (p = 0.008), as also did the EVLWI with 1 ml/kg (p = 0.03). The IAP decreased significantly from 12 to 10.5 mmHg (p < 0.0001). CONCLUSIONS: Net fluid removal by SLEDD or CVVH in the range observed in this study decreased IAP, GEDVI and EVLWI in critically ill patients although EVLWI reduction was modest.

Assessment of three minimally invasive continuous cardiac output measurement methods in critically ill patients and a review of the literature.

BACKGROUND: In this study we compared the accuracy of three continuous cardiac output (CCO) measurement methods, with intermittent transcardiopulmonary thermodilution (TPTD-CO) as the gold standard. The three studied CCO measurement methods were: uncalibrated peripheral pulse contour measurement (FCCO), calibrated central pulse contour measurement (PCCO), and CCO obtained by indirect Fick principle (NCCO). METHODS: We performed an observational study in 23 critically ill patients. Statistical analysis was done using Pearson's correlation and Bland-Altman analysis. A review of the relevant medical literature was performed. RESULTS: Only PCCO showed good correlation (R = 0.9) and agreement with a bias of 0.0 ± 0.8 L min⁻¹ and percentage error of 24.5% when compared to TPTD-CO. In patients with normal systemic vascular resistance index (SVRI > 1,700 dyne sec cm⁻5 m⁻²), NCCO (R = 0.8 and bias 0.4 ± 1.3 L min⁻¹) and FCCO (R = 0.8 and bias 0.1 ± 1 L min⁻¹) also produced reliable results. CONCLUSIONS: These results indicate that in our patient population, CCO can be most reliably monitored by calibrated central pulse contour measurements. All other methods appeared less accurate, especially in situations of low SVRI.

Can the abdominal perimeter be used as an accurate estimation of intra-abdominal pressure?

INTRODUCTION: Intra-abdominal pressure (IAP) is an important parameter and prognostic indicator of the patient's underlying physiologic status. Correct IAP measurement, therefore, is crucial. Most of the direct and indirect techniques are not free from risks and require some time and skills. This study looks at the possibility of using the abdominal perimeter (AP) as a quick estimation for IAP. METHODS: In total, 237 paired measurements were performed in 26 intensive care unit patients. The IAP was measured according to the recommendations of the World Society on Abdominal Compartment Syndrome via an indwelling bladder catheter using a pressure transducer. The AP was defined as the abdominal circumference at its largest point using body marks as reference for consecutive measurements. RESULTS: The male:female ratio was 1:1, age 69.8 +/- 15.2 yrs, Acute Physiology and Chronic Health Evaluation II score 26.5 +/- 9.2, and Simplified Acute Physiology Score II score 58 +/- 15.5. The number of measurements in each patient was 9.4 +/- 4.6. The IAP was 10.8 +/- 4.9 mm Hg, and the AP was 101 +/- 19.2 cm. There was a poor but statistically significant correlation between IAP and AP: AP = 1.8 x IAP + 81.6 (R2 = 0.21, p = 0.04), but the bias was considerable. The correlation was somewhat better between DeltaIAP (the difference between two consecutive IAP measurements) and DeltaAP (the difference between two consecutive AP measurements) in 210 paired measurements: DeltaAP = 0.4 x DeltaIAP + 0.1 (R2 = 0.24, p < 0.0001). The analysis according to Bland and Altman showed that DeltaIAP was almost identical to DeltaAP with a mean difference or bias of 0 +/- 3 (95% confidence interval: -0.4 to 0.4); however, the limits of agreement were large and thus reflect poor agreement. CONCLUSIONS: In view of the poor correlation between IAP and AP, the latter cannot be used as a clinical estimate for IAP. The correlation between DeltaIAP and DeltaAP was somewhat better, meaning that DeltaAP can be used as an estimate of the evolution of IAP over time; however, for making a definite diagnosis of intra-abdominal hypertension or abdominal compartment syndrome, the exact value of IAP needs to be measured.

In vitro validation of a novel method for continuous intra-abdominal pressure monitoring.

OBJECTIVE: Intra-abdominal pressure (IAP) measurement is important in daily clinical practice. Most measurement techniques vary in automaticity and reproducibility. This study tested a new fully automated continuous technique for IAP measurement, the CiMON. METHODS: Three IAP measurement catheters (a Foley manometer and two balloon-tipped catheters) contained in a 50-ml infusion bag were placed on the bottom of a half open 3-l container. To simulate IAH the container was filled with water using 5 cmH2O increments (0-30 cmH2O). Pressure was estimated by observers using the Foley manometer (IAP(FM)) and simultaneously recorded using two IAP monitors: IAP(spie) with Spiegelberg and IAP(CiM) with CiMON. Observers were blinded to the reference levels. Fifteen observers (three intensivists, four residents, two medical students, and six nurses) conducted three pressure readings at each of the seven pressure levels with the FM technique, giving 315 readings. These were paired with the automated IAP(spie) and IAP(CiM) readings and the height of the H2O column. RESULTS: The intra- and interobserver coefficients of variation (COVA) were low for all methods. There was no difference in the results between specialists, physicians in training, andnurses. Spearman's correlation coefficient (R2) values for all paired measurements were greater than 0.9, and Bland-Altman analysis comparing the reference H2O column, IAP(FM), and IAP(spie) to IAP(CiM) showed a very good agreement at all pressure levels (bias -0.1+/-0.6 cmH2O, 95%CI -0.2 to 0). There was a consistent, low underestimation of the reference H2O pressure by the Spiegelberg technique and a low overestimation at pressures below 20 cmH2O by both other techniques. CONCLUSIONS: All three measurement techniques, IAP(FM), IAP(spie), and IAP(CiM) have good agreement with the applied hydrostatic pressure in this in vitro model of IAP measurement.

Correlation between intra-abdominal and intracranial pressure in nontraumatic brain injury.

OBJECTIVE: To examine on the basis of a large number of measurements whether increased IAP is associated with increased ICP and decreased CPP in ventilated patients with nontraumatic brain injury. DESIGN AND SETTING: Observational clinical study in the medical and surgical intensive care unit of a tertiary teaching hospital. PATIENTS: We included 11 patients with nontraumatic brain injury who had an ICP and an IAP-monitoring device because of ischemic (n=4), hemorrhagic (n=5), and metabolic (n=2) encephalopathy. METHODS: IAP was continuously measured in the stomach, and ICP was continuously measured through an intraventricular catheter; 214 consecutive measurements were compared. Because of repeated measurements in the patients we used analysis of covariance to control for the variation in ICP and CPP between patients. MEASUREMENTS AND RESULTS: Patients' mean IAP was 3.8-11.8 mmHg, ICP 6.7-15 mmHg, and CPP 70.8-123 mmHg. For ICP the regression coefficient associated with IAP was 0.64+/-0.05 (95% CI 0.56-0.73, partial correlation 0.70) and for CPP -1.36+/-0.3 (95% CI -1.94 to -0.78; partial correlation -0.30). CONCLUSIONS: Increases in IAP are associated with increases in ICP and decreases in CPP in ventilated patients with nontraumatic brain injury, even at low levels of IAP.

Intra- and interobserver variability during in vitro validation of two novel methods for intra-abdominal pressure monitoring.

OBJECTIVE: Intra-abdominal pressure (IAP) measurement techniques vary in automaticity and reproducibility. This study evaluated the intra- and interobserver variability of two new IAP measurement techniques. METHODS: A one-half open, 30-l container was used with two IAP catheters (Foley Manometer, balloon-tipped catheter) contained in a 100-ml infusion bag. To simulate intra-abdominal hypertension the container was filled with water using 5-cm increments (0-25 cmH2O). Pressure was determined by observers using the Foley Manometer and simultaneously recorded using an IAP monitor. Observers were blinded to the reference levels. RESULTS: Fifteen observers conducted three pressure readings at each of the six pressure levels with the Foley technique, giving 270 readings. These were paired with the automated monitor readings and the height of the water column. The intra- and interobserver coefficients of variation were low for both methods. The Spearman correlation coefficient was higher than 0.9 for all paired measurements and Bland-Altman analysis comparing the reference H2O column to both measurement techniques showed a very good agreement at all pressure intervals (bias 0.1+/-0.6 cmH2O) and a consistent, low underestimation of the reference water column pressure by both techniques. CONCLUSIONS: Both the Foley Manometer and the IAP monitor are reliable and reproducible methods to measure IAP in this in vitro model. The coefficient of variation for each technique is low and decreases with increasing IAP, the monitor giving more reproducible results than the Foley Manometer.