IAH/ACS: The Rationale for Surveillance

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.

Association Between Ascites and Clinical Findings in Patients with Acute Pancreatitis: A Retrospective Study

BACKGROUND Complications are the most important outcome determinants for acute pancreatitis (AP). We designed this single-center retrospective study to evaluate the clinical findings (complications, disease severity, and outcomes) of 218 patients with AP and to identify variables associated with ascites. MATERIAL AND METHODS We extracted clinical data from consecutive patients with AP and divided them into 2 groups based on presence or absence of ascites. We compared disease severity, complications, and outcomes between groups. RESULTS We analyzed data from 218 patients with AP (43 with ascites and 175 without it). The patients with ascites had a more severe disease (higher incidence of pancreatic inflammation [90.70% vs 68.57%; P=0.003], higher modified computed tomography severity index score [2.00 (0.00-2.00) vs 4.00 (4.00-6.00); P<0.001], higher incidence of moderate/severe AP [53.49% vs 13.14%; P<0.001]) and poorer outcomes (higher incidence of ventilation [6.98% vs 0.57%; P=0.025] and vasopressor use [4.65% vs 0%; P=0.038], and longer hospital stays [10.00 (7.00-13.00) vs 8.00 (5.00-10.00); P=0.007]) than those without ascites. Moreover, patients with ascites also displayed a higher risk for pancreatic fluid collection (odds ratio [OR]=9.206; 95% confidence interval [CI], 2.613-32.447; P<0.001), renal failure (OR=5.732; 95% CI, 1.025-32.041; P=0.024), respiratory failure (OR=6.242; 95% CI, 1.034-37.654; P=0.029), and pleural effusion (OR=5.186; 95% CI, 1.381-19.483; P<0.001) than those without ascites. CONCLUSIONS The findings from the experience of a single center of patients with AP showed that pancreatic fluid collections, renal failure, respiratory failure, and pleural effusion were associated with the development of ascites.

The influence of intraabdominal pressure on the mortality rate of patients with acute pancreatitis

BACKGROUND/AIM

Intraabdominal hypertension (IAH) is a common clinical finding in patients with acute pancreatitis and is associated with poor prognosis. This study aimed to determine the impact of intraabdominal pressure (IAP) on the mortality rate in patients with acute pancreatitis in an intensive care unit.

MATERIALS AND METHODS

A total of 50 patients with acute pancreatitis were included in this prospective cohort study. Based on the obtained values of IAP, the patients were divided into two groups: those with normal IAP (n = 14) and increased IAP (n = 36). Mean values of IAP were compared with examined variables.

RESULTS

The mortality rate of the study group was 40%. Comparing the IAP and treatment outcomes, it was proved that there were statistically highly significant differences (P = 0.012). Increasing the value of IAP increased the mortality rate. Deceased patients in the IAH group had greater statistical significance of APACHE II score (P = 0.016), abdominal perfusion pressure (P = 0.048), lactate (P = 0.049), hematocrit (P = 0.039), Ranson's criteria on admission (P = 0.017), Ranson's criteria after 48 h (P = 0.010), Sequential Organ Failure Assessment score (P = 0.014), and body mass index (P = 0.012) compared to the surviving patients.

CONCLUSION

IAP has an impact on the increase of mortality rates in patients with acute pancreatitis.

Hemodynamic Changes Are Predictive of Coagulopathic Hemorrhage After Living Donor Liver Transplant

OBJECTIVES

Our goal was to evaluate the predictors of coagulopathic hemorrhage after living-donor liver transplant.

MATERIALS AND METHODS

We retrospectively evaluated 161 patients who had undergone living-donor liver transplant from July 2005 to April 2014 at a single medical institution. Of these patients, 32 developed hemorrhage after transplant. Patients were separated into those with coagulopathy-related hemorrhage (n=15) or noncoagulopathy-related hemorrhage (n=17) based on the results of computed tomography images. Predictors of hemorrhage after living-donor liver transplant evaluated in this study included preoperative, perioperative, and posttransplant factors and hemodynamic status.

RESULTS

Patients who developed coagulopathy-related hemorrhage had significantly lower pretransplant platelet counts (P = .040), a longer cold-ischemia time (P = .045), more blood loss (P = .040), and earlier onset of hemorrhage (P = .048) than patients who had noncoagulopathy-related hemorrhage after transplant. Results of the generalized estimating equation analysis showed that heart rate and central venous pressure differed significantly between the 2 groups of patients. Heart rates increased significantly during hemorrhage (P < .010). Central venous pressure was higher in the coagulopathic group (P = .005) than in the noncoagulopathic group.

CONCLUSIONS

Lower pretransplant platelet counts, longer cold ischemia time, more blood loss, earlier onset of hemorrhage, and higher central venous pressure level are indicators of coagulopathic hemorrhage after living-donor liver transplant.

Predicting and evaluation the severity in acute pancreatitis using a new modeling built on body mass index and intra-abdominal pressure

OBJECT

Acute pancreatitis (AP) keeps as severe medical diagnosis and treatment problem. Early evaluation for severity and risk stratification in patients with AP is very important. Some scoring system such as acute physiology and chronic health evaluation-II (APACHE-II), the computed tomography severity index (CTSI), Ranson's score and the bedside index of severity of AP (BISAP) have been used, nevertheless, there're a few shortcomings in these methods. The aim of this study was to construct a new modeling including intra-abdominal pressure (IAP) and body mass index (BMI) to evaluate the severity in AP.

METHODS

The study comprised of two independent cohorts of patients with AP, one set was used to develop modeling from Jinling hospital in the period between January 2013 and October 2016, 1073 patients were included in it; another set was used to validate modeling from the 81st hospital in the period between January 2012 and December 2016, 326 patients were included in it. The association between risk factors and severity of AP were assessed by univariable analysis; multivariable modeling was explored through stepwise selection regression. The change in IAP and BMI were combined to generate a regression equation as the new modeling. Statistical indexes were used to evaluate the value of the prediction in the new modeling.

RESULTS

Univariable analysis confirmed change in IAP and BMI to be significantly associated with severity of AP. The predict sensitivity, specificity, positive predictive value, negative predictive value and accuracy by the new modeling for severity of AP were 77.6%, 82.6%, 71.9%, 87.5% and 74.9% respectively in the developing dataset. There were significant differences between the new modeling and other scoring systems in these parameters (P < 0.05). In addition, a comparison of the area under receiver operating characteristic curves of them showed a statistically significant difference (P < 0.05). The same results could be found in the validating dataset.

CONCLUSIONS

A new modeling based on IAP and BMI is more likely to predict the severity of AP.

A survey of critical care nurses' knowledge of intra-abdominal hypertension and abdominal compartment syndrome

BACKGROUND

Intra-abdominal hypertension and abdominal compartment syndrome are potentially life threatening conditions. Critical care nurses need to understand the factors that predispose patients to intra-abdominal hypertension (IAH) and abdominal compartment syndrome (ACS). Predicting and managing IAH and ACS are important to improve health outcomes.

AIM

The aim of this paper was to (1) assess the knowledge of Australian critical care nurses about current IAH and ACS practice guidelines, measurement techniques, predictors for the development of IAH and ACS and (2) identify barriers in recognizing IAH, ACS and measuring IAP.

METHODS

Between October 2014 and April 2015 86 registered nurses employed in the area of critical care were recruited via the form to participate in an on-line, 19-item questionnaire. The survey was distributed to critical care nurses via the Australian College of Critical Care Nurses (ACCCN) mailing list and directly to intensive care units via The majority of participants were women (n=62) all participants were registered nurses employed in critical care the response rate was 3.2%. The study design was used to establish demographic data, employment data, and individuals' knowledge related to IAH and ACS. Participants had the option to write hand written responses in addition to selecting a closed question response.

RESULTS

The results showed that most survey participants were able to identify some obvious causes of IAH. However, less than 20% were able to recognize less apparent indices of risk. A lack of education related to IAP monitoring was identified by nearly half (44.2%) of respondents as the primary barrier to monitoring IAP.

CONCLUSION

Critical care clinicians' knowledge of IAH and ACS is generally low in the areas of presentation and outcomes of IAH and ACS requiring tailored and targeted educational interventions.

Low Transmission of Airway Pressures to the Abdomen in Mechanically Ventilated Patients With or Without Acute Respiratory Failure and Intra-Abdominal Hypertension

PURPOSE

Intra-abdominal pressure, measured at end expiration, may depend on ventilator settings and transmission of intrathoracic pressure. We determined the transmission of positive intrathoracic pressure during mechanical ventilation at inspiration and expiration into the abdominal compartment.

METHODS AND RESULTS

We included 9 patients after uncomplicated cardiac surgery and 9 with acute respiratory failure. Intravesical pressures were measured thrice (reproducibility of 1.8%) and averaged, at the end of each inspiratory and expiratory hold maneuvers of 5 seconds. Transmission, the change in intra-abdominal over intrathoracic pressures from end inspiration to end expiration, was about 8%. End-expiratory intra-abdominal pressure was lower than "total" intra-abdominal pressure over the entire respiratory cycle by 0.34 cm H₂O. It was 0.73 cm H₂O higher than "true" intra-abdominal pressure over the entire respiratory cycle, taking transmission into account. The percentage error was 3% for total and 10% for true pressure. Results did not differ among patients with or without acute respiratory failure and decreased respiratory compliance or between those with (≥12 mm Hg, n = 5) or without intra-abdominal hypertension.

CONCLUSIONS

Transmitted airway pressure only slightly affects intra-abdominal pressure in mechanically ventilated patients, irrespective of respiratory compliance and baseline intra-abdominal pressure values. End-expiratory measurements referenced against atmospheric pressure may suffice for clinical practice.

Study of intra-abdominal hypertension prevalence and awareness level among experienced ICU medical staff

BACKGROUND

Intra-abdominal hypertension (IAH) is a disease with high morbidity and mortality among critically ill patients. The study's objectives were to explore the prevalence of IAH and physicians' awareness of the 2013 World Society of Abdominal Compartment Syndrome (WSACS) guidelines in Chinese intensive care units (ICUs).

METHODS

A cross-sectional study of four ICUs in Southwestern China was conducted from June 17 to August 2, 2014. Adult patients admitted to the ICU for more than 24 h, with bladder catheter but without obvious intravesical pressure (IVP) measurement contraindications, were recruited. Intensivists with more than 5 years of ICU working experience were also recruited. Epidemiological information, potential IAH risk factors, IVP measurements and questionnaire results were recorded.

RESULTS

Forty-one patients were selected. Fifteen (36.59 %) had IVP ≥ 12 mmHg. SOFA (Sequential Organ Failure Assessment) hepatic and neurological sub-scores were utilized as independent predictors for IAH via logistic backward analysis. Thirty-seven intensivists participated in the survey (response rate: 80.43 %). The average score of each center was less than 35 points. All physicians believed the IAH prevalence in their departments was no more than 20.00 %. A significant negative correlation was observed between the intensivists' awareness of the 2013 WSACS guidelines and the IAH prevalence in each center (r = -0.975, P = 0.025).

CONCLUSIONS

The prevalence and independent predictors of IAH among the surveyed population are similar to the reports in the literature. Intensivists generally have a low awareness of the 2013 WSACS guidelines. A systematic guideline training program is vital for improving the efficiency of the diagnosis and treatment of IAH.

Reliability of intra-abdominal pressure measurements using the modified Kron technique

OBJECTIVES

Assessment of intra-abdominal pressure (IAP) and the likelihood of abdominal compartment syndrome using valid and reliable measures is an important tool in the assessment of critically ill patients. The current method of relying on a single IAP per measurement period to determine patient clinical status raises the question: is a single intermittent IAP measurement an accurate indicator of clinical status or should more than one measurement be taken per measurement period?

METHODS

This study sought to assess the reliability of IAP measurements. Measurements were taken using the modified Kron technique. A total of two transvesical intra-abdominal pressure measurements were undertaken per patient using a standardized protocol. Recordings were taken at intervals of 5 minutes.

RESULTS

The majority of participants (58%) were surgical patients. Thirty-two were males and the mean age was 58 years (SD: 16·7 years). The concordance correlation coefficient between the two measurements was 0·95. Both the scatter and Bland-Altman plots demonstrate that the comparisons of two measurements are highly reproducible.

CONCLUSION

The findings of this study suggest that conducting two IAP measurements on single patient produce comparable results; therefore, there appears to be no advantage in doing two IAP measurements on a single patient. The measurement of an IAP requires the implementation of a standardized protocol and competent and credentialed assessors trained in the procedure.

Pathophysiology and management of acute kidney injury in the setting of abdominal compartment syndrome

Abdominal compartment syndrome (ACS) is defined as an organ dysfunction caused by intra-abdominal hypertension (IAH). Up to 4.2% of the patients in intensive care unit may develop IAH with it being an independent predictor of mortality. However, overall, it still remains a relatively underdiagnosed condition, part in because physical examination alone is very unreliable. Acute kidney injury is one of the most consistently described organ dysfunctions with oliguria being one of the earliest clinical signs of IAH. We recommend that any patient with evidence of new onset oliguria in the setting of distended abdomen, unexplained respiratory failure, with or without hypotension should be suspected of having IAH/ACS. Intravesicular pressure measurement represents a safe, rapid, and cost-effective method of diagnosing IAH. We hereby review the pathophysiology, diagnosis, and management of ACS and its association with acute kidney injury.

Early screening to identify patients at risk of developing intra-abdominal hypertension and abdominal compartment syndrome

BACKGROUND

To develop a screening tool to identify patients at risk of developing intra-abdominal hypertension (IAH) and abdominal compartment syndrome (ACS) within 24 h of a patient's admission to intensive care unit (ICU).

METHODS

Prospective, observational study of 403 consecutively enrolled patients with an indwelling catheter, admitted to a mixed medical-surgical ICU in a tertiary referral, university hospital. Intra-abdominal pressure was measured at least twice daily and IAH and ACS defined as per consensus definitions.

RESULTS

Thirty-nine per cent of patients developed IAH and 2% developed ACS. Abdominal distension, hemoperitoneum/pneumoperitoneum/intra-peritoneal fluid collection, obesity, intravenous fluid received > 2.3 l, abbreviated Sequential Organ Failure Assessment score > 4 points and lactate > 1.4 mmol/l were identified as independent predictors of IAH upon admission to ICU. The presence of three or more of these risk factors at admission identified patients that would develop IAH with a sensitivity of 75% and a specificity of 76%, the development of grades II, III and IV IAH with a sensitivity of 91% and a specificity of 62%. Patients that developed IAH required a significantly longer duration of mechanical ventilation and ICU care. Patients that developed grades II-IV IAH had a significantly higher rate of ICU mortality.

CONCLUSION

IAH is a common clinical entity in the intensive care setting that is associated with morbidity and mortality. A screening tool, based on data readily available within a patient's first 24 h in ICU, was developed and effectively identified patients that required intra-abdominal pressure monitoring.

Management of intra-abdominal hypertension and abdominal compartment syndrome: a review

Patients in the intensive care unit (ICU) are at risk of developing of intra abdominal hypertension (IAH) and abdominal compartment syndrome (ACS).

Aim: This review seeks to define IAH and ACS, identify the aetiology and presentation of IAH and ACS, identify IAP measurement techniques, identify current management and discuss the implications of IAH and ACS for nursing practice. A search of the electronic databases was supervised by a health librarian. The electronic data bases Cumulative Index of Nursing and Allied Health Literature (CINAHL); Medline, EMBASE, and the World Wide Web was undertaken from 1996- January 2011 using MeSH and key words which included but not limited to: abdominal compartment syndrome, intra -abdominal hypertension, intra-abdominal pressure in adult populations met the search criteria and were reviewed by three authors using a critical appraisal tool. Data derived from the retrieved material are discussed under the following themes: (1) etiology of intra-abdominal hypertension; (2) strategies for measuring intra-abdominal pressure (3) the manifestation of abdominal compartment syndrome; and (4) the importance of nursing assessment, observation and interventions. Intra-abdominal pressure (IAP) and abdominal compartment syndrome (ACS) have the potential to alter organ perfusion and compromise organ function.

Intra-abdominal pressure as a predictor of acute kidney injury in postoperative abdominal surgery

OBJECTIVES

The purpose of this study was to determine if intra-abdominal pressure (IAP) could predict acute renal injury (AKI) in the postoperative period of abdominal surgeries, and which would be its cutoff value.

PATIENTS AND METHODS

A prospective observational study was conducted in the period from January 2010 to March 2011 in the Intensive Care Units (ICUs) of the University Hospital of Botucatu Medical School, UNESP. Consecutive patients undergoing abdominal surgery were included in the study. Initial evaluation, at admission in ICU, was performed in order to obtain demographic, clinical surgical and therapeutic data. Evaluation of IAP was obtained by the intravesical method, four times per day, and renal function was evaluated during the patient's stay in the ICU until discharge, death or occurrence of AKI.

RESULTS

A total of 60 patients were evaluated, 16 patients developed intra-abdominal hypertension (IAH), 45 developed an abnormal IAP (>7 mmHg) and 26 developed AKI. The first IAP at the time of admission to the ICU was able to predict the occurrence of AKI (area under the receiver-operating characteristic curve was 0.669; p=0.029) with the best cutoff point (by Youden index method) ≥ 7.68 mmHg, sensitivity of 87%, specificity of 46% at this point. The serial assessment of this parameter did not added prognostic value to initial evaluation.

CONCLUSION

IAH was frequent in patients undergoing abdominal surgeries during ICU stay, and it predicted the occurrence of AKI. Serial assessments of IAP did not provided better discriminatory power than initial evaluation.

Observational study of intra-abdominal pressure monitoring in acute pancreatitis

BACKGROUND

Intra-abdominal hypertension (IAH) is predictive of adverse outcome in critically ill patients; however, its role in acute pancreatitis is unclear, and prospective studies are lacking. We aimed to determine the overall incidence and predictive value of IAH on mortality in acute pancreatitis.

METHODS

Transvesical IAP was measured on admission and every 4 hours within high-dependency unit/intensive care unit. Serum biochemistry and physiologic parameters permitted calculation of Acute Physiology and Chronic Health Evaluation II, Sequential Organ Failure Assessment, Imrie, and Ranson scores. The primary end point was 30-day mortality.

RESULTS

A total of 218 patients with acute pancreatitis were recruited; 30-day mortality was greater in patients with IAH (IAP ≥12 mmHg; 37%) than no IAH (2%; P < .001). A total of 14% of patients had IAH on admission; another 3% developed IAH in hospital. Mortality was greater in the latter group (37% vs 50%; P < .01). In the majority of cases IAH developed in line with other organ failure; however, there were several patients in whom the development of IAH appeared to be the sentinel event before rapid clinical decline. An IAP threshold of 9 mmHg had best predictive value for mortality (sensitivity 86%, specificity 87%; area under the ROC curve 0.91). This finding was comparable with other validated markers of severe pancreatitis (Imrie ≥3: sensitivity 51%, specificity 70%; Acute Physiology and Chronic Health Evaluation II: sensitivity 67%, specificity 96%; C-reactive protein >150: sensitivity 89%, specificity 83%).

CONCLUSION

IAP is a good predictor of mortality and organ failure in acute pancreatitis and compares favorably with other validated prognostic scores. Whether IAH is a phenomenon causative of organ failure or an epiphenomenon, occurring in conjunction with other organ dysfunction, remains unclear.

Tonometry as a predictor of inadequate splanchnic perfusion in an intra-abdominal hypertension animal model

BACKGROUND

The gastrointestinal system is the most sensitive to the presence of intra-abdominal hypertension. We aimed to assess the early prognostic value of gastric air tonometry as a predictor of inadequate splanchnic perfusion and determine its relation with abdominal perfusion pressure (APP).

METHODS

Twenty-five Large White swine were used for this study. A control group and two study groups were included, in which intra-abdominal pressure (IAP) was elevated with Co2 to 20 and 30 mmHg during 5 h. We measured the intramucosal gastric pH (pHim) and determined gastric luminal PCO2 (PgCO2) and PgCO2gap (gastric luminal CO2-arterial CO2) to evaluate gastric acidity. APP was indirectly obtained through IAP and mean arterial pressure. Additionally, histopathologic samples of small intestine were obtained and analyzed.

RESULTS

pHim showed a decrease in IAP groups, with statistical significance in the 30 mmHg group, 90 min after stabilization period (P < 0.01). Serum lactate showed delayed alteration when compared with pHim, with significant increase, 180 min after stabilization (P < 0.05). The values of PgCO2 and PCO2gap were increased in IAP groups, being statistically significant in the 30 mmHg group, 120 and 150 min, respectively, after stabilization. In increased IAP groups, there was a time progressive decrease of APP, with statistically significant differences observed between groups at 20 min (P < 0.001). The histopathology study revealed parenchymal injury of the intestine at 30 mmHg.

CONCLUSIONS

Tonometry is sensitive to the increase in IAP and relates to the reduction of APP generated by splanchnic hypoperfusion.

Should we measure intra-abdominal pressures in every intensive care patient?

Intra-abdominal pressure (IAP) is seldom measured by default in intensive care patients. This review summarises the current evidence on the prevalence and risk factors of intra-abdominal hypertension (IAH) to assist the decision-making for IAP monitoring.IAH occurs in 20% to 40% of intensive care patients. High body mass index (BMI), abdominal surgery, liver dysfunction/ascites, hypotension/vasoactive therapy, respiratory failure and excessive fluid balance are risk factors of IAH in the general ICU population. IAP monitoring is strongly supported in mechanically ventilated patients with severe burns, severe trauma, severe acute pancreatitis, liver failure or ruptured aortic aneurysms. The risk of developing IAH is minimal in mechanically ventilated patients with positive end-expiratory pressure < 10 cmH2O, PaO2/FiO2 > 300, and BMI < 30 and without pancreatitis, hepatic failure/cirrhosis with ascites, gastrointestinal bleeding or laparotomy and the use of vasopressors/inotropes on admission. In these patients, omitting IAP measurements might be considered.In conclusions, clear guidelines to select the patients in whom IAP measurements should be performed cannot be given at present. In addition to IAP measurements in at-risk patients, a clinical assessment of the signs of IAH should be a part of every ICU patient's bedside evaluation, leading to prompt IAP monitoring in case of the slightest suspicion of IAH development.

Comparison of superior vena cava and femoroiliac vein pressure according to intra-abdominal pressure

Background

Previous studies have shown a good agreement between central venous pressure (CVP) measurements from catheters placed in superior vena cava and catheters placed in the abdominal cava/common iliac vein. However, the influence of intra-abdominal pressure on such measurements remains unknown.

Methods

We conducted a prospective, observational study in a tertiary teaching hospital. We enrolled patients who had indwelling catheters in both superior vena cava (double lumen catheter) and femoroiliac veins (dialysis catheter) and into the bladder. Pressures were measured from all the sites, CVP, femoroiliac venous pressure (FIVP), and intra-abdominal pressure.

Results

A total of 30 patients were enrolled (age 62 ± 14 years; SAPS II 62 (52–76)). Fifty complete sets of measurements were performed. All of the studied patients were mechanically ventilated (PEP 3 cmH₂0 (2–5)). We observed that the concordance between CVP and FIVP decreased when intra-abdominal pressure increased. We identified 14 mmHg as the best intra-abdominal pressure cutoff, and we found that CVP and FIVP were significantly more in agreement below this threshold than above (94% versus 50%, P = 0.002).

Conclusions

We reported that intra-abdominal pressure affected agreement between CVP measurements from catheter placed in superior vena cava and catheters placed in the femoroiliac vein. Agreement was excellent when intra-abdominal pressure was below 14 mmHg.

Evaluating abdominal oedema during experimental sepsis using an isotope technique

PURPOSE

Abdominal oedema is common in sepsis. A technique for the study of such oedema may guide in the fluid regime of these patients.

PROCEDURES

We modified a double-isotope technique to evaluate abdominal organ oedema and fluid extravasation in 24 healthy or endotoxin-exposed ('septic') piglets. Two different markers were used: red blood cells (RBC) labelled with Technetium-99m ((99m)Tc) and Transferrin labelled with Indium111 ((111)In). Images were acquired on a dual-head gamma camera. Microscopic evaluation of tissue biopsies was performed to compare data with the isotope technique.

RESULTS

No (99m)Tc activity was measured in the plasma fraction in blood sampled after labelling. Similarly, after molecular size gel chromatography, (111)In activity was exclusively found in the high molecular fraction of the plasma. Extravasation of transferrin, indicating the degree of abdominal oedema, was 4·06 times higher in the LPS group compared to the healthy controls (P<0·0001). Abdominal free fluid, studied in 3 animals, had as high (111)In activity as in plasma, but no (99m)Tc activity. Intestinal lymphatic vessel size was higher in LPS (3·7 ± 1·1 μm) compared to control animals (0·6 + 0·2 μm; P<0·001) and oedema correlated to villus diameter (R(2) = 0·918) and lymphatic diameter (R(2) = 0·758). A correlation between a normalized index of oedema formation (NI) and intra-abdominal pressure (IAP) was also found: NI = 0·46*IAP-3·3 (R(2) = 0·56).

CONCLUSIONS

The technique enables almost continuous recording of abdominal oedema formation and may be a valuable tool in experimental research, with the potential to be applied in the clinic.

Current recognition and management of intra-abdominal hypertension and abdominal compartment syndrome among tertiary Chinese intensive care physicians

This survey was designed to clarify the current understanding and clinical management of intra-abdominal hypertension (IAH)/abdominal compartment syndrome (ACS) among intensive care physicians in tertiary Chinese hospitals. A postal twenty-question questionnaire was sent to 141 physicians in different intensive care units (ICUs). A total of 108 (76.6%) questionnaires were returned. Among these, three quarters worked in combined medical-surgical ICUs and nearly 80% had primary training in internal or emergency medicine. Average ICU beds, annual admission, ICU length of stay, acute physiology and chronic health evaluation (APACHE) II score, and mortality were 18.2 beds, 764.5 cases, 8.3 d, 19.4, and 21.1%, respectively. Of the respondents, 30.6% never measured intra-abdominal pressure (IAP). Although the vast majority of the ICUs adopted the exclusively transvesicular method, the overwhelming majority (88.0%) only measured IAP when there was a clinical suspicion of IAH/ACS and only 29.3% measured either often or routinely. Moreover, 84.0% used the wrong priming saline volume while 88.0% zeroed at reference points which were not in consistence with the standard method for IAP monitoring recommended by the World Society of Abdominal Compartment Syndrome. ACS was suspected mainly when there was a distended abdomen (92%), worsening oliguria (80%), and increased ventilatory support requirement (68%). Common causes for IAH/ACS were "third-spacing from massive volume resuscitation in different settings" (88%), "intra-abdominal bleeding", and "liver failure with ascites" (52% for both). Though 60% respondents would recommend surgical decompression when the IAP exceeded 25 mmHg, accompanied by signs of organ dysfunction, nearly three quarters of respondents preferred diuresis and dialysis. A total of 68% of respondents would recommend paracentesis in the treatment for ACS. In conclusion, urgent systematic education is absolutely necessary for most intensive care physicians in China to help to establish clear diagnostic criteria and appropriate management for these common, but life-threatening, diseases.

Compartment syndromes from head to toe

Compartment syndrome is defined as the dysfunction of organs/tissues within the compartment due to limited blood supply caused by increased pressure within the compartment. The aim of this article is to introduce and discuss acute compartment syndromes that are essential for critical care physicians to recognize and manage. Various pathophysiological mechanisms (ischemia-reperfusion syndrome, direct trauma, localized bleeding) could lead to increased compartmental pressure and decreased blood flow through the intracompartmental capillaries. Although compartment syndromes are described in virtually all body regions, the etiology, diagnosis, treatment, and prevention are best characterized for three key body regions (extremity, abdominal, and thoracic compartment syndromes). Compartment syndromes can be classified as either primary (pathology/injury is within the compartment) or secondary (no primary pathology or injury within the compartment), and based on the etiology (e.g., trauma, burn, sepsis). A recently described phenomenon is the "multiple" compartment syndrome or "poly"-compartment syndrome, which is usually a complication of a severe shock and massive resuscitation. The prevention of compartment syndromes is based on preemptive open management of compartments (primary syndromes) in high-risk patients and/or careful fluid resuscitation (both primary and secondary syndromes) to limit interstitial swelling.

Effect of increased intra-abdominal pressure and decompressive laparotomy on aerated lung volume distribution

Increased intra-abdominal pressure (IAP) is common in intensive care patients, affecting aerated lung volume distribution. The current study deals with the effect of increased IAP and decompressive laparotomy on aerated lung volume distribution. The serial whole-lung computed tomography scans of 16 patients with increased IAP were retrospectively analyzed between July 2006 and July 2008 and compared to controls. The IAP increased from (12.1+/-2.3) mmHg on admission to (25.2+/-3.6) mmHg (P<0.01) before decompressive laparotomy and decreased to (14.7+/-2.8) mmHg after decompressive laparotomy. Mean time from admission to decompressive laparotomy and length of intensive-care unit (ICU) stay were 26 h and 16.2 d, respectively. The percentage of normally aerated lung volume on admission was significantly lower than that of controls (P<0.01). Prior to decompressive laparotomy, the total lung volume and percentage of normally aerated lung were significantly less in patients compared to controls (P<0.01), and the absolute volume of non-aerated lung and percentage of non-aerated lung were significantly higher in patients (P<0.01). Peak inspiratory pressure, partial pressure of carbon dioxide in arterial blood, and central venous pressure were higher in patients, while the ratio of partial pressure of arterial O(2) to the fraction of inspired O(2) (PaO(2)/FIO(2)) was decreased relative to controls prior to laparotomy. An approximately 1.8 cm greater cranial displacement of the diaphragm in patients versus controls was observed before laparotomy. The sagittal diameter of the lung at the T6 level was significantly increased compared to controls on admission (P<0.01). After laparotomy, the volume and percentage of non-aerated lung decreased significantly while the percentage of normally aerated lung volume increased significantly (P<0.01). In conclusion, increased IAP decreases total lung volume while increasing non-aerated lung volume. Decompressive laparotomy is associated with resolution of these effects on lung volumes.

Understanding of Abdominal Compartment Syndrome among Pediatric Healthcare Providers

Background. The sparse reporting of abdominal compartment syndrome (ACS) in the pediatric literature may reflect inadequate awareness and recognition among pediatric healthcare providers (HCP). Purpose. To assess awareness of ACS, knowledge of the definition and intraabdominal pressure (IAP) measurement techniques used among pediatric HCP. Method. A written survey distributed at two pediatric critical care conferences. Results. Forty-seven percent of 1107 questionnaires were completed. Participants included pediatric intensivists, pediatric nurses, and others. Seventy-seven percent (n = 513) of participants had heard of ACS. Only 46.8% defined ACS correctly. The threshold IAP value used to define ACS was variable among participants. About one-quarter of participants (83/343), had never measured IAP. Conclusion. Twenty-three percent of HCP surveyed were unaware of ACS. Criteria used to define ACS were variable. Focused education on recognition of ACS and measuring IAP should be promoted among pediatric HCP.

Intra-abdominal hypertension: detecting and managing a lethal complication of critical illness

Intra-abdominal hypertension occurs in 50% of all patients admitted to the intensive care unit and is associated with significant morbidity and mortality. Intra-abdominal hypertension is defined as a sustained, pathologic rise in intra-abdominal pressure to 12 mm Hg or more. Patients with intra-abdominal hypertension may progress to abdominal compartment syndrome. Early identification and treatment of this condition will improve patient outcome. Patients at risk for intra-abdominal hypertension include those with major traumatic injury, major surgery, sepsis, burns, pancreatitis, ileus, and massive fluid resuscitation. Predisposing factors include decreased abdominal wall compliance, increased intraluminal contents, increased peritoneal cavity contents, and capillary leak/fluid resuscitation.

Ischemia as a possible effect of increased intra-abdominal pressure on central nervous system cytokines, lactate and perfusion pressures

INTRODUCTION

The aims of our study were to evaluate the impact of increased intra-abdominal pressure (IAP) on central nervous system (CNS) cytokines (Interleukin 6 and tumor necrosis factor), lactate and perfusion pressures, testing the hypothesis that intra-abdominal hypertension (IAH) may possibly lead to CNS ischemia.

METHODS

Fifteen pigs were studied. Helium pneumoperitoneum was established and IAP was increased initially at 20 mmHg and subsequently at 45 mmHg, which was finally followed by abdominal desufflation. Interleukin 6 (IL-6), tumor necrosis factor alpha (TNFa) and lactate were measured in the cerebrospinal fluid (CSF) and intracranial (ICP), intraspinal (ISP), cerebral perfusion (CPP) and spinal perfusion (SPP) pressures recorded.

RESULTS

Increased IAP (20 mmHg) was followed by a statistically significant increase in IL-6 (p = 0.028), lactate (p = 0.017), ICP (p < 0.001) and ISP (p = 0.001) and a significant decrease in CPP (p = 0.013) and SPP (p = 0.002). However, further increase of IAP (45 mmHg) was accompanied by an increase in mean arterial pressure due to compensatory tachycardia, followed by an increase in CPP and SPP and a decrease of cytokines and lactate.

CONCLUSIONS

IAH resulted in a decrease of CPP and SPP lower than 60 mmHg and an increase of all ischemic mediators, indicating CNS ischemia; on the other hand, restoration of perfusion pressures above this threshold decreased all ischemic indicators, irrespective of the level of IAH.

Vacuum-assisted closure device enhances recovery of critically ill patients following emergency surgical procedures

Introduction

Critically ill surgical patients frequently develop intra-abdominal hypertension (IAH) leading to abdominal compartment syndrome (ACS) with subsequent high mortality. We compared two temporary abdominal closure systems (Bogota bag and vacuum-assisted closure (VAC) device) in intra-abdominal pressure (IAP) control.

Methods

This prospective study with a historical control included 66 patients admitted to a medical and surgical intensive care unit (ICU) of a tertiary care referral center (Careggi Hospital, Florence, Italy) from January 2006 to April 2009. The control group included patients consecutively treated with the Bogota bag (Jan 2006-Oct 2007), whereas the prospective group was comprised of patients treated with a VAC. All patients underwent abdominal decompressive surgery. Groups were compared based upon their IAP, SOFA score, serial arterial lactates, the duration of having their abdomen open, the need for mechanical ventilation (MV) along with length of ICU and hospital stay and mortality. Data were collected from the time of abdominal decompression until the end of pressure monitoring.

Results

The Bogota and VAC groups were similar with regards to demography, admission diagnosis, severity of illness, and IAH grading. The VAC system was more effective in controlling IAP (P < 0.01) and normalizing serum lactates (P < 0.001) as compared to the Bogota bag during the first 24 hours after surgical decompression. There was no significant difference between the SOFA scores. When compared to the Bogota, the VAC group had a faster abdominal closure time (4.4 vs 6.6 days, P = 0.025), shorter duration of MV (7.1 vs 9.9 days, P = 0.039), decreased ICU length of stay (LOS) (13.3 vs 19.2 days, P = 0.024) and hospital LOS (28.5 vs 34.9 days; P = 0.019). Mortality rate did not differ significantly between the two groups.

Conclusions

Patients with abdominal compartment syndrome who were treated with VAC decompression had a faster abdominal closure rate and earlier discharge from the ICU as compared to similar patients treated with the Bogota bag.