Incidence and prognosis of intra-abdominal hypertension in critically ill medical patients: a prospective epidemiological study

Acute Gastrointestinal Injury in Critically Ill Patients in a South Indian Intensive Care Unit: A Prospective, Observational, Preliminary Study

Introduction The acute gastrointestinal injury (AGI) score was proposed by the Working Group on Abdominal Problems of the European Society of Intensive Care Medicine (ESICM) as a tool to define and grade gut dysfunction. There have not been any studies in India to validate this tool. The objective of this preliminary study was primarily to study the frequency of AGI in the first week of ICU stay in critically ill patients in our intensive care unit (ICU). We also sought to determine the risk factors predisposing to the development of AGI and to determine the prognostic implication of gastrointestinal (GI) injury in critically ill patients. Materials and methods A prospective, observational, preliminary, single-center study was conducted on critically ill patients (APACHE II > 8) who were on enteral tube feeds and admitted to a mixed ICU of a tertiary care hospital. Anthropometric data, admission diagnosis, APACHE II score, and comorbidities were recorded. Data of daily heart rate, mean arterial pressure, dose of vasopressors, intra-abdominal pressure, fluid balance, feeding intolerance, mechanical ventilation, and laboratory tests were noted for the first seven days of ICU stay or till ICU discharge, whichever was earlier. The occurrence of AGI score (1-4) during the first seven days of critical illness was the primary outcome of interest. Patient outcome at 28 days was recorded and the impact of the occurrence of AGI on patient outcome was analyzed using the Chi-square test. The patient characteristics associated with AGI were characterized as risk factors and analyzed using a multivariate model. Results Data were collected from 33 patients over 201 patient days. The frequency of acute GI dysfunction in the first seven days of ICU stay in our group of patients was 45.45% (15/33). APACHE II, fluid balance, creatinine, and lactate were identified as possible predictors of GI injury based on existing literature. These four variables were entered into an ordinal logistic regression model to assess their ability to predict the occurrence of GI Injury. When fitted into a predictive model, only fluid balance and creatinine were predictive of the final model (p-value < 0.05). A greater fluid balance was predictive in the final model of the development of GI injury; however, it showed negligible clinical significance (OR: 1.00033, 95% CI: 1.000051-1.00061). Lower creatinine levels were predictive in the final model of the development of AGI Injury, as demonstrated by the negative coefficient. Creatinine also had a greater clinical significance (OR: 0.63, 95% CI: 0.44-0.90) in the development of AGI. The impact of the AGI scores on mortality was analyzed. The number of patient days with higher AGI scores was significantly associated with increased mortality at 28 days (p-value < 0.001). Conclusion The study showed that nearly half of the critically ill patients included in the study developed acute GI dysfunction. We could not identify any predictors of GI injury based on our results. The result suggested an association between the severity of GI dysfunction and mortality at 28 days.

MALDI-TOF MS combined with AUC method for tigecycline susceptibility testing in Escherichia coli

Objectives

The wide spread of tet(X4) gene orthologues in the environment, food, poultry and humans is causing serious tigecycline resistance. Consequently, developing a fast and universal method to detect tigecycline resistance has become increasingly important.

Methods

During 2019-2022, 116 Escherichia coli isolates were obtained from nine provinces in China. All isolates were tested for their susceptibility to antimicrobial agents by the microdilution broth method and for the tet(X4) gene by PCR. Ten tet(X4)-positive E. coli isolates were used to confirm certain conditions, including the optimal incubation time, the optimal concentration of tigecycline, and the cut-off of the relative growth (RG) value.

Results

The optimal time and concentration of tigecycline for separation of susceptible and resistant isolates was 2 h and 4 mg/L, and the RG cut-off value was 0.4. We validated whether the experiment was feasible using 116 isolates of E. coli. The method yielded a susceptibility of 94.9% (95% CI: 81.4%-99.1%) and a specificity of 96.1% (95% CI: 88.3%-99.0%).

Conclusions

This research has shown that this optical antimicrobial susceptibility testing method can rapidly differentiate between susceptible and resistant phenotypes in isolates of E. coli. In the same range as the current gold-standard methods, the clinical turnaround time is reduced from 48 h to 2.5 h. The above results suggest that the method has splendid specificity and operationality.

Abdominal compartment syndrome as a complication of endoscopic carbon dioxide insufflation in a patient with malignant bowel obstruction: a case report

BACKGROUND

A self-expandable metal stent is often placed as a bridge to elective surgical treatment of left-sided malignant obstruction of the colon because it allows for primary anastomosis without the need for a temporary stoma, which has a positive impact on the patient's quality of life. However, although a relatively safe procedure, colonic stenting can have complications that require emergency surgery. This case report describes a rare case of abdominal compartment syndrome that occurred as a complication of endoscopic insufflation during colonic stenting.

CASE PRESENTATION

The patient was a 72-year-old woman who presented complaining of several days of constipation and loss of appetite. Computed tomography of the abdomen revealed obstruction of the sigmoid colon by a tumor. There were no symptoms or computed tomography findings to suggest perforation. Therefore, an attempt was made to insert a self-expandable metal stent. Acute respiratory disturbance and a change in consciousness occurred during the stenting procedure, with marked abdominal distention. Abdominal compartment syndrome was diagnosed and treated by decompressive laparotomy.

CONCLUSIONS

To the best of our knowledge, this is the first reported case of abdominal compartment syndrome as a complication of endoscopic insufflation during colonic stenting. The possibility of abdominal compartment syndrome should be considered if acute respiratory disturbance or altered consciousness occurs during endoscopic procedure in a patient with malignant bowel obstruction.

Intracranial Hypertension following Acute Mesenteric Ischemia: A Case Study on the Multiple Compartment Syndrome

In this case study, we describe a 25-year-old male who was admitted due to a severe traumatic brain injury, requiring invasive intracranial pressure monitoring. At 48 hours posttrauma, he developed intracranial hypertension refractory to medical treatment without tomographic changes in the brain. Subsequently, intra-abdominal hypertension and tomographic signs of abdominal surgical pathology were observed. An exploratory laparotomy was performed with an intraoperative diagnosis of acute mesenteric ischemia. After surgical intervention for the abdominal pathology, intracranial pressure was restored to physiological values with a favorable recovery of the patient. In this report, the relationship between intracranial pressure and intra-abdominal pressure is discussed, highlighting the delicate association between the brain, abdomen, and thorax. Measures should be taken to avoid increases in intra-abdominal pressure in neurocritical patients. When treating intracranial hypertension refractory to conventional measures, abdominal causes and multiple compartment syndrome must be considered. The cranial compartment has physiological interdependence with other body compartments, where one can be modified by variations from another, giving rise to the concept of multiple compartment syndrome. Understanding this relationship is fundamental for a comprehensive approach of the neurocritical patient. To the best of our knowledge, this is the first report of a comatose patient post-traumatic brain injury, who developed medically unresponsive intracranial hypertension secondary to acute mesenteric ischemia, in which surgical resolution of intra-abdominal pathology resulted in intracranial pressure normalization and restitutio ad integrum of neurological status.

Sánchez-Margallo F, Eugenia Candanosa-Aranda I, Poelaert J, Castellanos G, L. N. G. Malbrain M. The pathophysiological impact of intra-abdominal hypertension in pigs

BACKGROUND

Intra-abdominal hypertension and abdominal compartment syndrome are common with clinically significant consequences. We investigated the pathophysiological effects of raised IAP as part of a more extensive exploratory animal study. The study design included both pneumoperitoneum and mechanical intestinal obstruction models.

METHODS

Forty-nine female swine were divided into six groups: a control group (Cr; n = 5), three pneumoperitoneum groups with IAPs of 20mmHg (Pn20; n = 10), 30mmHg (Pn30; n = 10), 40mmHg (Pn40; n = 10), and two mechanical intestinal occlusion groups with IAPs of 20mmHg (MIO20; n = 9) and 30mmHg (MIO30; n = 5).

RESULTS

There were significant changes (p<0.05) noted in all organ systems, most notably systolic blood pressure (SBP) (p<0.001), cardiac index (CI) (p = 0.003), stroke volume index (SVI) (p<0.001), mean pulmonary airway pressure (MPP) (p<0.001), compliance (p<0.001), pO2 (p = 0.003), bicarbonate (p = 0.041), hemoglobin (p = 0.012), lipase (p = 0.041), total bilirubin (p = 0.041), gastric pH (p<0.001), calculated glomerular filtration rate (GFR) (p<0.001), and urine output (p<0.001). SVV increased progressively as the IAP increased with no obvious changes in intravascular volume status. There were no significant differences between the models regarding their impact on cardiovascular, respiratory, renal and gastrointestinal systems. However, significant differences were noted between the two models at 30mmHg, with MIO30 showing worse metabolic and hematological parameters, and Pn30 and Pn40 showing a more rapid rise in creatinine.

CONCLUSIONS

This study identified and quantified the impact of intra-abdominal hypertension at different pressures on several organ systems and highlighted the significance of even short-lived elevations. Two models of intra-abdominal pressure were used, with a mechanical obstruction model showing more rapid changes in metabolic and haematological changes. These may represent different underlying cellular and vascular pathophysiological processes, but this remains unclear.

Intra-abdominal hypertension and abdominal compartment syndrome in acute pancreatitis

Intra-abdominal hypertension (IAH) and abdominal compartment syndrome (ACS) are underrecognized entities in patients of acute pancreatitis (AP). IAH develops in 30% to 60% and ACS in 15% to 30% of all AP patients and they are markers of severe disease with high morbidity and mortality. The detrimental effect of increased IAP has been recognized in several organ systems, including the central nervous system, cardiovascular, respiratory, renal and gastrointestinal systems. The pathophysiology of IAH/ACS development in patients with AP is multifactorial. Pathogenetic mechanisms include over-zealous fluid management, visceral edema, ileus, peripancreatic fluid collections, ascites and retroperitoneal edema. Laboratory and imaging markers are neither sensitive nor specific enough to detect IAH/ACS and intra-abdominal pressure (IAP) monitoring is vital for early diagnosis and the management of patients of AP with IAH/ACS. The treatment of IAH/ACS requires a multi-modality approach with both medical and surgical attention. Medical management consists of nasogastric/rectal decompression, prokinetics, fluid management and diuretics or hemodialysis. If conservative management is not effective, percutaneous drainage of fluid collection or ascites is necessary. Despite medical management, if IAP worsens, surgical decompression is warranted. The review discusses the relevance of IAH/ACS in patients of AP and its management.

Intra-Abdominal Hypertension and Compartment Syndrome after Pediatric Liver Transplantation: Incidence, Risk Factors and Outcome

In pediatric liver transplantation (pLT), the risk for the manifestation and relevance of intra-abdominal hypertension (IAH) and abdominal compartment syndrome (ACS) is high. This observational study aimed to evaluate the incidence, relevance and risk factors for IAH and ACS by monitoring the intra-abdominal pressure (IAP), macro- and microcirculation (near-infrared spectroscopy (NIRS)), clinical and laboratory status and outcomes of 27 patients (16 female) after pLT (median age at pLT 35 months). Of the patients, 85% developed an elevated IAP, most of them mild. However, 17% achieved IAH° 3, 13% achieved IAH° 4 and 63% developed ACS. A multiple linear regression analysis identified aortal hepatic artery anastomosis and cold ischemia time (CIT) as risk factors for increased IAP and longer CIT and staged abdominal wall closure for ACS. ACS patients had significantly longer mechanical ventilation (p = 0.004) and LOS-PICU (p = 0.003). No significant correlation between NIRS or biliary complications and IAH or ACS could be shown. IAH and ACS after pLT were frequent. NIRS or grade of IAH alone should not be used for monitoring. A longer CIT is an important risk factor for higher IAP and ACS. Therefore, approaches such as the ex vivo machine perfusion of donor organs, reducing CIT effects on them, have great potential. Our study provides important basics for studying such approaches.

Role of intra-abdominal pressure measurement in patients with acute abdomen requiring exploratory laparotomy

<b>Introduction:</b> Acute abdomen is one of the most common surgical emergencies faced by a surgeon. Monitoring Intra-Abdominal Pressure (IAP) in patients with acute abdomen referred for exploratory laparotomy may help guide the need for early intervention. </br></br> <b>Aim:</b> This study was performed to determine whether preoperative IAP had any significant association with organ failure as assessed using SOFA score. Furthermore, effect of IAP on patient outcome in terms of hospital stay, mortality was also evaluated. </br></br> <b>Materials and methods:</b> 60 patients above 18 years of age presenting with acute abdomen requiring exploratory laparotomy were included in this prospective observational study from November 2013 until March 2015. IAP and SOFA scores were calculated at the time of admission. The outcome of patients was assessed in terms of hospital stay, morbidity and mortality. The correlation between IAP and SOFA scores was also assessed to determine the risk of organ failure. The inferences were drawn with the use of SPSS v22.0 statistical software. ANOVA, Chi-square and Student’s t-test were used in the analysis. </br></br> <b> Results:</b> There was a positive correlation between SOFA score and IAP; and this correlation was found to be statistically significant with Pearson’s correlation coefficient being 0.6247 and significance levels being <0.0001. Both hospital stay and mortality positively correlated with the degree of IAP. </br></br> <b> Conclusions:</b> IAP should be routinely measured in patients with acute abdomen requiring exploratory laparotomy. Patients with preoperatively raised IAP should be referred for emergency surgery as soon as possible for better outcome.

Focused ultrasonography for septic shock resuscitation

PURPOSE OF REVIEW

Severe sepsis with septic shock is the most common cause of death among critically ill patients. Mortality has decreased substantially over the last decade but recent data has shown that opportunities remain for the improvement of early and targeted therapy. This review discusses published data regarding the role of focused ultrasonography in septic shock resuscitation.

RECENT FINDINGS

Early categorization of the cardiovascular phenotypes with echocardiography can be crucial for timely diagnosis and targeted therapy of patients with septic shock. In the last few years, markers of volume status and volume responsiveness have been investigated, serving as valuable tools for targeting volume therapy in the care of both spontaneously breathing and mechanically ventilated patients. In tandem, investigators have highlighted findings of extravascular volume with ultrasonographic evaluation to compliment de-escalation of resuscitation efforts when appropriate. Furthermore, special attention has been given to resuscitation efforts of patients in septic shock with right ventricular failure.

SUMMARY

Severe sepsis with septic shock is an insidious disease process that continues to take lives. In more recent years, data have emerged suggesting the utility of bedside ultrasonography for early cardiovascular categorization, goal directed resuscitation, and appropriate cardiovascular support based on its changing phenotypes.

The prevalence, incidence and mortality associated with intra-abdominal hypertension among patients in intensive care units of a low-income country: a cohort study

Background: Intra-abdominal hypertension (IAH) is sustained increase in intra-abdominal pressure (IAP) ≥12 mmHg in adults and ≥10 mmHg in children. IAH has been noted to be associated with increased morbidity and mortality among critically ill patients. Measurement of IAP is common among at risk patients in the developed world. However, it has not received due attention in the majority of intensive care units (ICUs) in low-income countries, Uganda being one of these. This is evidenced by paucity of data and lack of protocols from the Ugandan Ministry of Health. This multi-center study was thus conducted to assess the prevalence, incidence and mortality associated with IAH among patients admitted to Ugandan ICUs.Methods:A multi-center prospective cohort study was conducted from September 2017 to February 2018 at three ICUs in Uganda. We consecutively enrolled 126 patients into the study. IAP was measured using the Harrahil manometer technique. Categorical variables were analyzed using the Chi square test and continuous variables analyzed using the t-test and Man Whitney test. The prevalence and incidence were determined using proportions and mortality was determined using survival analysis.Results:The median age was 33 years (26-48.5) for the patients without IAH and 42 years (29-55) for those with IAH. The majority of the patients were male and 9.6% of the patients were below 18 years. The prevalence of IAH was 62.7 (CI 54.1-71.3), whereas the 24 hour and 72 hour incidence of IAH was 9.3% (CI 1.3-17.2) and 14.3 % (CI 4.1-24.4), respectively.  Mortality was higher in patients with IAH compared to those without (p-value 0.003 and 0.028, mean and maximum IAP, respectively). Conclusion:We found a high prevalence and incidence of IAH among critically ill patients, associated with a high mortality. Routine screening for IAH can preempt management strategies to mitigate this.

Intra-Abdominal Hypertension Is Responsible for False Negatives to the Passive Leg Raising Test

OBJECTIVES

To compare the passive leg raising test ability to predict fluid responsiveness in patients with and without intra-abdominal hypertension.

DESIGN

Observational study.

SETTING

Medical ICU.

PATIENTS

Mechanically ventilated patients monitored with a PiCCO2 device (Pulsion Medical Systems, Feldkirchen, Germany) in whom fluid expansion was planned, with (intra-abdominal hypertension+) and without (intra-abdominal hypertension-) intra-abdominal hypertension, defined by an intra-abdominal pressure greater than or equal to 12 mm Hg (bladder pressure).

INTERVENTIONS

We measured the changes in cardiac index during passive leg raising and after volume expansion. The passive leg raising test was defined as positive if it increased cardiac index greater than or equal to 10%. Fluid responsiveness was defined by a fluid-induced increase in cardiac index greater than or equal to 15%.

MEASUREMENTS AND MAIN RESULTS

We included 60 patients, 30 without intra-abdominal hypertension (15 fluid responders and 15 fluid nonresponders) and 30 with intra-abdominal hypertension (21 fluid responders and nine fluid nonresponders). The intra-abdominal pressure at baseline was 4 ± 3 mm Hg in intra-abdominal hypertension- and 20 ± 6 mm Hg in intra-abdominal hypertension+ patients (p < 0.01). In intra-abdominal hypertension- patients with fluid responsiveness, cardiac index increased by 25% ± 19% during passive leg raising and by 35% ± 14% after volume expansion. The passive leg raising test was positive in 14 patients. The passive leg raising test was negative in all intra-abdominal hypertension- patients without fluid responsiveness. In intra-abdominal hypertension+ patients with fluid responsiveness, cardiac index increased by 10% ± 14% during passive leg raising (p = 0.01 vs intra-abdominal hypertension- patients) and by 32% ± 18% during volume expansion (p = 0.72 vs intra-abdominal hypertension- patients). Among these patients, the passive leg raising test was negative in 15 patients (false negatives) and positive in six patients (true positives). Among the nine intra-abdominal hypertension+ patients without fluid responsiveness, the passive leg raising test was negative in all but one patient. The area under the receiver operating characteristic curve of the passive leg raising test for detecting fluid responsiveness was 0.98 ± 0.02 (p < 0.001 vs 0.5) in intra-abdominal hypertension- patients and 0.60 ± 0.11 in intra-abdominal hypertension+ patients (p = 0.37 vs 0.5).

CONCLUSIONS

Intra-abdominal hypertension is responsible for some false negatives to the passive leg raising test.

Intra-Abdominal Hypertension Is More Common Than Previously Thought: A Prospective Study in a Mixed Medical-Surgical ICU

OBJECTIVES

To determine the prevalence of intra-abdominal hypertension in mixed medical-surgical critically ill patients using modern definitions and measurement techniques. Secondarily to determine variables associated with intra-abdominal hypertension and ICU mortality.

DESIGN

A prospective observational study.

SETTING

Single institution trauma, medical and surgical ICU in Canada.

PATIENTS

Consecutive adult patients admitted to the ICU (n = 285).

INTERVENTION

Intra-abdominal pressure measurements twice a day during admission to the ICU.

MEASUREMENTS AND MAIN RESULTS

In 285 patients who met inclusion criteria, 30% were diagnosed with intra-abdominal hypertension at admission and a further 15% developed intra-abdominal hypertension during admission. The prevalence of abdominal compartment syndrome was 3%. Obesity, sepsis, mechanical ventilation, and 24-hour fluid balance (> 3 L) were all independent predictors for intra-abdominal hypertension. Intra-abdominal hypertension occurred in 28% of nonventilated patients. Admission type (medical vs surgical vs trauma) was not a significant predictor of intra-abdominal hypertension. Overall ICU mortality was 20% and was significantly higher for patients with intra-abdominal hypertension (30%) compared with patients without intra-abdominal hypertension (11%). Intra-abdominal hypertension of any grade was an independent predictor of mortality (odds ratio, 3.33; 95% CI, 1.46-7.57).

CONCLUSIONS

Intra-abdominal hypertension is common in both surgical and nonsurgical patients in the intensive care setting and was found to be independently associated with mortality. Despite prior reports to the contrary, intra-abdominal hypertension develops in nonventilated patients and in patients who do not have intra-abdominal hypertension at admission. Intra-abdominal pressure monitoring is inexpensive, provides valuable clinical information, and there may be a role for its routine measurement in the ICU. Future work should evaluate the impact of early interventions for patients with intra-abdominal hypertension.

Comparison of Melatonin, Hypertonic Saline, and Hydroxyethyl Starch for Resuscitation of Secondary Intra-Abdominal Hypertension in an Animal Model

A variety of agents may have a beneficial effect in reducing injury-induced intestinal edema of fluid, but studies confirming the efficacy and mechanisms of these agents in secondary intra-abdominal hypertension (IAH) are lacking. This study was to compare the effectiveness of melatonin, 7.5% hypertonic saline (HS), and hydroxyethyl starch 130/0.4 (HES) on the resuscitation of secondary IAH in a rat model. Female SD rats were divided into: sham group, shock group, lactated Ringer solution (LR) group, melatonin group, HS group, and HES group. Except for the sham group, all rats underwent a combination of inducing portal hypertension, hemorrhaging to a MAP of 40 mmHg for 2 hr, and using an abdominal restraint device. The collected blood was reinfused and the rats were treated with LR (30ml/h), melatonin (50 mg/kg) + LR, HS (6 ml/kg) + LR, and HES (30 ml/kg) + LR, respectively. The shock group received no fluids. LR was continuously infused for 6hr. The intestinal permeability, immunofluorescence of tight junction proteins, transmission electron microscopy, level of inflammatory mediators (TNF-a, IL-1β, IL-6) and of biochemical markers of oxidative stress (malondialdehyde, myeloperoxidase activity, and glutathione peroxidase) were assessed. Expressions of the protein kinase B (Akt) and of tight junction proteins were detected by Western blot. Compared with LR, HS, and HES, melatonin was associated with less inflammatory and oxidative injury, less intestinal permeability and injury, and lower incidence of secondary IAH in this model. The salutary effect of melatonin in this model was associated with the upregulation of intestinal Akt phosphorylation.

Inferior vena cava diameter variation compared with pulse pressure variation as predictors of fluid responsiveness in patients with sepsis

BACKGROUND

Currently, physicians employ pulse pressure variation (PPV) as a gold standard for predicting fluid responsiveness. However, employing ultrasonography in intensive care units is increasing, including using the ultrasonography for assessment of fluid responsiveness. Data comparing the performance of both methods are still lacking. This is the reason for the present study.

MATERIALS AND METHODS

We conducted a prospective observational study in patients with sepsis requiring fluid challenge. The PPV, inferior vena cava diameter variation (IVDV), stroke volume variation (SVV), and the other hemodynamic variables were recorded before and after fluid challenges. Fluid responders were identified when cardiac output increased more than 15% after fluid loading.

RESULTS

A total of 29 patients with sepsis were enrolled in this study. Sixteen (55.2%) were fluid responders. Threshold values to predict fluid responsiveness were 13.8% of PPV (sensitivity 100% and specificity 84.6%), 10.2% of IVDV (sensitivity 75% and specificity 76.9%) and 10.7% of SVV (sensitivity 81.3% and specificity 76.9%). The area under the curves of receiver operating characteristic showed that PPV (0.909, 95% confidence interval [CI], 0.784-1.00) and SVV (0.812, 95% CI, 0.644-0.981) had greater performance than IVDV (0.688, 95% CI, 0.480-0.895) regarding fluid responsiveness assessment.

CONCLUSIONS

The present study demonstrated better performance of the PPV than the IVDV. A threshold value more than 10% may be used for identifying fluid responders.

Melatonin prevents secondary intra-abdominal hypertension in rats possibly through inhibition of the p38 MAPK pathway

Exogenous administration of melatonin has been demonstrated to down-regulate inflammatory responses and attenuate organ damage in various models. However, the salutary effect of melatonin against secondary intra-abdominal hypertension (IAH) remains unclear. This study sought to test the influence of melatonin on secondary IAH in a pathophysiological rat model and the underlying mechanisms involved. Before resuscitation, male rats underwent a combination of induced portal hypertension, applying an abdominal restraint device, and hemorrhaging to mean arterial pressure (MAP) of 40mmHg for 2h. After blood reinfusion, the rats were treated with lactated Ringer solution (LR) (30mL/h), melatonin (50mg/kg) +LR, and SB-203580 (10μmol/kg)+LR. LR was continuously infused for 6h. MAP, the inferior vena cava pressure and urine output were monitored. Histopathological examination, immunofluorescence of tight junction proteins, and transmission electron microscopy were administered. Intestinal permeability, myeloperoxidase activity, malondialdehyde, glutathione peroxidase, and levels of TNF-a, IL-2, and IL-6, were assessed. The expression of extracellular signal-regulated kinase, p38, c-Jun NH2-terminal kinase, translocation of nuclear factor kappa B subunit, signal transducers and activators of transcription and tight junction proteins were detected by Western blot. We found that melatonin inhibited the inflammatory responses, decreased expression of p38 MAPK, attenuated intestinal injury, and prevented secondary IAH. Moreover, administration of SB203580 abolished the increase in p38 MAPK and also attenuated intestinal injury. These data indicate that melatonin exerts a protective effect in intestine in secondary IAH primarily by attenuating the inflammatory responses which are in part attributable to p38 MAPK inhibition.

Mild to moderate intra-abdominal hypertension: Does it matter?

This review summarizes the epidemiology, pathophysiological consequences and impact on outcome of mild to moderate (Grade I to II) intra-abdominal hypertension (IAH), points out possible pitfalls in available treatment recommendations and focuses on tasks for future research in the field. IAH occurs in about 40% of ICU patients. Whereas the prevalence of abdominal compartment syndrome seems to be decreasing, the prevalence of IAH does not. More than half of IAH patients present with IAH grade I and approximately a quarter with IAH grade II. However, most of the studies have addressed IAH as a yes-or-no variable, with little or no attention to different severity grades. Even mild IAH can have a negative impact on tissue perfusion and microcirculation and be associated with an increased length of stay and duration of mechanical ventilation. However, the impact of IAH and its different grades on mortality is controversial. The influence of intra-abdominal pressure (IAP) on outcome most likely depends on patient and disease characteristics and the concomitant macro- and microcirculation. Therefore, management might differ significantly. Today, clear triggers for interventions in different patient groups with mild to moderate IAH are not defined. Further studies are needed to clarify the clinical importance of mild to moderate IAH identifying clear triggers for interventions to lower the IAP.

Bladder Pressure Measurements in Patients Admitted to a Medical Intensive Care Unit

BACKGROUND

Intra-abdominal hypertension is identified as an independent risk factor for death. However, this pathophysiological state is not always considered in patients in medical intensive care units and is frequently underdiagnosed.

METHODS

Serial bladder pressure measurements were recorded in patients admitted to the medical intensive care units to determine the frequency of intra-abdominal hypertension.

RESULTS

This study included 53 patients with a mean age of 59.0 ± 17.7 years. The average admission intra-abdominal pressure was 10.0 ± 5.4 mm Hg with a range of 0 to 28 mm Hg. Eleven patients (21%) had an initial pressure reading above normal (>12 mm Hg). Peak airway pressures were higher, and PaO2/FiO2 ratios were lower in patients with an initial pressure >12 mm Hg.

CONCLUSIONS

Bladder pressure measurements provide an easy method to estimate intra-abdominal pressures and provide an additional tool for the physiologic assessment of critically ill patients.

Intra-abdominal hypertension does not predict renal recovery or in-hospital mortality in critically ill patients with acute kidney injury

BACKGROUND

Although emerging evidence suggests that intra-abdominal hypertension (IAH) is a predictor of the development of acute kidney injury (AKI), it remains unclear whether the presence of IAH is a predictor of prognosis in patients with AKI. The purpose of this study was to assess whether the presence of IAH could predict prognosis in critically ill patients with AKI. The prognostic value of urinary biomarkers was also determined.

METHODS

In this prospective observational study, we enrolled 57 patients with established AKI, who were admitted to the intensive care unit between February 2012 and June 2014. IAH was defined as a sustained elevation in intra-abdominal pressure of ≥12 mmHg, in three consecutive measurements performed daily on the first 3 days. Urinary neutrophil gelatinase-associated lipocalin (NGAL), liver-type fatty acid-binding protein, and simplified acute physiology score II score at the time of admission were also examined.

RESULTS

IAH was observed in 78.9% of patients. The in-hospital mortality was 21.1%, and renal recovery during hospitalization was achieved in 40.4% of patients. Although high urinary NGAL [odds ratio (OR), 1.015] and liver-type fatty acid-binding protein (OR, 1.003) were found to be independent predictors of renal recovery, IAH was not. High urinary NGAL (OR, 1.003) and a high simplified acute physiology score II score (OR, 1.102) were independent predictors of in-hospital mortality, while IAH or urinary liver-type fatty acid-binding protein was not.

CONCLUSION

Although IAH is prevalent in critically ill patients with AKI, it did not predict AKI prognosis. However, urinary NGAL was found to be a useful predictor of both renal recovery and in-hospital mortality.

Incidence, Risk Factors, and Prognosis of Intra-Abdominal Hypertension in Critically Ill Children: A Prospective Epidemiological Study

PURPOSE

To assess the incidence, risk factors, and outcomes of intra-abdominal hypertension (IAH) in a pediatric intensive care unit (PICU).

METHODS

Prospective cohort study from January 2011 to January 2013. All children consecutively admitted to the PICU, staying more than 24 hours and requiring bladder catheterization, were included in the study. On admission, demographic data and risk factors for IAH were studied. The intra-abdominal pressure was measured every 6 hours through a bladder catheter until discharge, death, or removal of the catheter.

RESULTS

Of the 175 patients, 22 (12.6%) had IAH and 7 (4%) had abdominal compartment syndrome during the intensive care unit (ICU) stay. The independent risk factors associated with IAH were the presence of abdominal distension (odds ratio [OR] 7.1; 95% confidence interval [CI], 2.6-19.9; P < .0001) and a plateau pressure of more than 30 cm H2O (OR 6.42; 95% CI, 2.13-19.36; P = .01). The presence of IAH was associated with higher mortality (40.9% vs 15.6%; P = .01) and prolonged ICU stay (19.5 [3-97] vs 8 [1-104] days, OR 1.02; 95% CI, 1.00-1.04; P = .02). Thirty-three (18.8%) patients died in the ICU, and IAH was an independent risk factor for mortality (OR 6.98; 95% CI, 1.75-27.86; P = .006).

CONCLUSION

Intra-abdominal hypertension does occur in about 13% of the critically ill children, albeit less frequently than adult patients, probably related to a better compliance of the abdominal wall. The presence of abdominal distension and a plateau pressure of more than 30 cm H2O was found to be independent predictors of IAH. Children with IAH had higher mortality rate and more prolonged ICU stay.

Intra-abdominal hypertension in the ICU - a prospective epidemiological study

The aim of this prospective study is to examine the frequency and the severity of intra-abdominal hypertension in a mixed ICU of the University hospital.

Intra-abdominal pressure correlates with extracellular water content

Background

Secondary increase in intra-abdominal pressure (IAP) may result from extra-abdominal pathology, such as massive fluid resuscitation, capillary leak or sepsis. All these conditions increase the extravascular water content. The aim of this study was to analyze the relationship between IAP and body water volume.

Material and Methods

Adult patients treated for sepsis or septic shock with acute kidney injury (AKI) and patients undergoing elective pharyngolaryngeal or orthopedic surgery were enrolled. IAP was measured in the urinary bladder. Total body water (TBW), extracellular water content (ECW) and volume excess (VE) were measured by whole body bioimpedance. Among critically ill patients, all parameters were analyzed over three consecutive days, and parameters were evaluated perioperatively in surgical patients.

Results

One hundred twenty patients were studied. Taken together, the correlations between IAP and VE, TBW, and ECW were measured at 408 time points. In all participants, IAP strongly correlated with ECW and VE. In critically ill patients, IAP correlated with ECW and VE. In surgical patients, IAP correlated with ECW and TBW. IAP strongly correlated with ECW and VE in the mixed population. IAP also correlated with VE in critically ill patients. ROC curve analysis showed that ECW and VE might be discriminative parameters of risk for increased IAP.

Conclusion

IAP strongly correlates with ECW.

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.

Acute elevation of intra-abdominal pressure contributes to extravascular shift of fluid and proteins in an experimental porcine model

BACKGROUND

Intra-abdominal hypertension and abdominal compartment syndrome contribute significantly to increased morbidity and mortality in critically ill patients. This study describes pathophysiologic effects of the acutely elevated intra-abdominal pressure on microvascular fluid exchange and microcirculation. The resulting changes could contribute to development of organ dysfunction or failure.

METHODS

16 pigs were randomly allocated to a control-group (C-group) or an interventional group (P-group). After 60 min of stabilization, intra-abdominal pressure of the P-group animals was elevated to 15 mmHg by Helium insufflation and after 120 min to a level of 30 mmHg for two more hours. The C-group animals were observed without insufflation of gas. Laboratory and hemodynamic parameters, plasma volume, plasma colloid osmotic pressure, total tissue water content, tissue perfusion, markers of inflammation and cerebral energy metabolism were measured and net fluid balance and fluid extravasation rates calculated. Analysis of variance for repeated measurements with post-tests were used to evaluate the results with respect to differences within or between the groups.

RESULTS

In the C-group hematocrit, net fluid balance, plasma volume and the fluid extravasation rate remained essentially unchanged throughout the study as opposed to the increase in hematocrit (P < 0.001), fluid extravasation rate (P < 0.05) and decrease in plasma volume (P < 0.001) of the P-group. Hemodynamic parameters remained stable or were slightly elevated in the C-group while the P-group demonstrated an increase in femoral venous pressure (P < 0.001), right atrial pressure (P < 0.001), pulmonary capillary wedge pressure (P < 0.01) and mean pulmonary arterial pressure (P < 0.001). The protein mass decreased in both study groups but was significantly lower in the P-group as compared with the C-group, after 240 min of intervention. The increased intra-abdominal pressure was associated with elevated intracranial pressure and reduced tissue perfusion of the pancreas and the gastric- and intestinal mucosa.

CONCLUSION

Elevation of intra-abdominal pressure has an immediate impact on microvascular fluid extravasation leading to plasma volume contraction, reduced cardiac output and deranged perfusion of abdominal organs.

Expanded measurements of intra-abdominal pressure do not increase the detection rate of intra-abdominal hypertension: a single-center observational study

OBJECTIVE

Intra-abdominal hypertension may contribute to a poor outcome. Whether limiting intra-abdominal pressure measurements to preselected at-risk patients allows for sufficient detection of intra-abdominal hypertension is unclear. We aimed to clarify whether expanded intra-abdominal pressure monitoring results in an increased detection rate of intra-abdominal hypertension.

DESIGN

Retrospective observational study.

SETTING

General ICU of University Hospital.

PATIENTS

Consecutive adult ICU patients from 2004 to 2011.

INTERVENTIONS

Intra-abdominal pressure measurements in predefined at-risk patients.

MEASUREMENTS AND MAIN RESULTS

Prospectively collected data of 2,696 admissions were divided into three subgroups according to the intra-abdominal pressure measurement policy in different years: 1) 2004-2005, mechanically ventilated patients with at least one additional risk factor for intra-abdominal hypertension (multiple trauma, abdominal surgery, pancreatitis, post-cardiopulmonary resuscitation, fluid resuscitation > 5 L/24 hr, vasoactive or inotropic support, and renal replacement therapy); 2) 2006-2009, all mechanically ventilated patients expected to stay for more than or equal to 24 hours; and 3) 2010-2011, mechanically ventilated patients with a body mass index greater than 30 kg/m, positive end-expiratory pressure more than 10 cm H2O, PaO2/FIO2 less than 300, use of vasopressors/inotropes, pancreatitis, hepatic failure/cirrhosis with ascites, gastrointestinal bleeding, or postlaparotomy. In all, 2,696 patients were studied, and 1,241 patients (46.0%) underwent intra-abdominal pressure monitoring. The intra-abdominal pressure was measured in 31.7%, 55.6%, and 41.1% of patients during the first, second, and third time periods (p < 0.001), and intra-abdominal hypertension (intra-abdominal pressure ≥ 12 mm Hg) occurred in 19.9%, 20.3%, and 20.1% of patients, respectively (p = 0.972). The mean intra-abdominal pressure at admission day was an independent predictor of mortality in patients with intra-abdominal pressure measurements started within the first 24 hours (odds ratio, 1.046 [95% CI, 1.019-1.072]). The mortality of patients with intra-abdominal hypertension was 29.8% versus 18.6% in those without intra-abdominal hypertension (p < 0.001).

CONCLUSIONS

Expanding the measurement of intra-abdominal pressure to more than 50% of intensive care admissions does not increase the detection rate of intra-abdominal hypertension. In patients with intra-abdominal pressure monitoring, the mean intra-abdominal pressure on the admission day is an independent predictor of mortality.

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.

The role of intestinal mucosa injury induced by intra-abdominal hypertension in the development of abdominal compartment syndrome and multiple organ dysfunction syndrome

Introduction

Abdominal distension is common in critical illness. There is a growing recognition that intra-abdominal hypertension (IAH) may complicate nonsurgical critical illness as well as after abdominal surgery. However, the pathophysiological basis of the injury to the intestinal mucosal barrier and its influence on the onset of abdominal compartment syndrome (ACS) and multiorgan dysfunction syndrome (MODS) remain unclear. We measured intestinal microcirculatory blood flow (MBF) during periods of raised intra-abdominal pressure (IAP) and examined how this influenced intestinal permeability, systemic endotoxin release, and histopathological changes.

Methods

To test different grades of IAH to the injury of intestinal mucosa, 96 New Zealand white rabbits aged 5 to 6 months were exposed to increased IAP under nitrogen pneumoperitoneum of 15 mmHg or 25 mmHg for 2, 4 or 6 hours. MBF was measured using a laser Doppler probe placed against the jejunal mucosa through a small laparotomy. Fluorescein isothiocyanate (FITC)-conjugated dextran was administered by gavage. Intestinal injury and permeability were measured using assays for serum FITC-dextran and endotoxin, respectively, after each increase in IAP. Structural injury to the intestinal mucosa at different levels of IAH was confirmed by light and transmission electron microscopy.

Results

MBF reduced from baseline by 40% when IAP was 15 mmHg for 2 hours. This doubled to 81% when IAP was 25 mmHg for 6 hours. Each indicator of intestinal injury increased significantly, proportionately with IAP elevation and exposure time. Baseline serum FITC-dextran was 9.30 (± SD 6.00) μg/ml, rising to 46.89 (±13.43) μg/ml after 15 mmHg IAP for 4 hours (P <0.01), and 284.59 (± 45.18) μg/ml after 25 mmHg IAP for 6 hours (P <0.01). Endotoxin levels showed the same pattern. After prolonged exposure to increased IAP, microscopy showed erosion and necrosis of jejunal villi, mitochondria swelling and discontinuous intracellular tight junctions.

Conclusions

Intra-abdominal hypertension can significantly reduce MBF in the intestinal mucosa, increase intestinal permeability, result in endotoxemia, and lead to irreversible damage to the mitochondria and necrosis of the gut mucosa. The dysfunction of the intestinal mucosal barrier may be one of the important initial factors responsible for the onset of ACS and MODS.

Sublingual microcirculation in patients with intra-abdominal hypertension: a pilot study in 15 critically ill patients

PURPOSE

The purpose of the study is to clarify whether increased intra-abdominal pressure (IAP) is associated with sublingual microcirculatory alterations in intensive care patients.

METHODS

Fifteen adult, mechanically ventilated patients were included if their IAP was at least 12 mm Hg for at least 12 hours within the first 3 days after admission to the intensive care unit. Sublingual sidestream dark field (SDF) images were recorded twice a day for 7 days.

RESULTS

Median (interquartile range) IAP at inclusion was 14.5 (12.5-16.0) mm Hg. The total vascular density of small vessels at the sublingual area was 13.1 (10.6-14.3) per square millimeter at baseline; the proportion of perfused vessels, 78.9% (69.6%-86.2%); and perfused vessels density, 12.4 (10.8-13.8) per square millimeter. The calculated indices suggested relatively good blood flow in the capillaries, with a De Backer score of 9.0 (8.3-10.2) and a microvascular blood flow of 3.0 (2.9-3.0). Blood flow heterogeneity index was 0.3 (0.1-0.5) at study entry. Despite that IAP, vasopressors dose, and arterial lactate decreased significantly over time, no significant changes were observed in sublingual microvascular density or blood flow. Weak correlations of microvascular blood flow (positive) and heterogeneity index (negative) were detected with both mean arterial pressure and abdominal perfusion pressure.

CONCLUSIONS

Neither grade I or II intra-abdominal hypertension (IAP from 12 to 18 mm Hg) is associated with significant changes of sublingual microcirculation in intensive care patients. Correlation analysis indicates better microvascular blood flow at higher mean arterial pressure and abdominal perfusion pressure levels.

Experimental intra-abdominal hypertension influences airway pressure limits for lung protective mechanical ventilation

BACKGROUND

Intra-abdominal hypertension (IAH) and abdominal compartment syndrome (ACS) may complicate monitoring of pulmonary mechanics owing to their impact on the respiratory system. However, recommendations for mechanical ventilation of patients with IAH/ACS and the interpretation of thoracoabdominal interactions remain unclear. Our study aimed to characterize the influence of elevated intra-abdominal pressure (IAP) and positive end-expiratory pressure (PEEP) on airway plateau pressure (PPLAT) and bladder pressure (PBLAD).

METHODS

Nine deeply anesthetized swine were mechanically ventilated via tracheostomy: volume-controlled mode at tidal volume (VT) of 10 mL/kg, frequency of 15, inspiratory-expiratory ratio of 1:2, and PEEP of 1 and 10 cm H2O (PEEP1 and PEEP10, respectively). A tracheostomy tube was placed in the peritoneal cavity, and IAP levels of 5, 10, 15, 20, and 25 mm Hg were applied, using a continuous positive airway pressure system. At each IAP level, PBLAD and airway pressure measurements were performed during both PEEP1 and PEEP10.

RESULTS

PBLAD increased as experimental IAP rose (y = 0.83x + 0.5; R = 0.98; p < 0.001 at PEEP1). Minimal underestimation of IAP by PBLAD was observed (-2.5 ± 0.8 mm Hg at an IAP of 10-25 mm Hg). Applying PEEP10 did not significantly affect the correlation between experimental IAP and PBLAD. Approximately 50% of the PBLAD (in cm H2O) was reflected by changes in PPLAT, regardless of the PEEP level applied. Increasing IAP did not influence hemodynamics at any level of IAP generated.

CONCLUSION

With minimal underestimation, PBLAD measurements closely correlated with experimentally regulated IAP, independent of the PEEP level applied. For each PEEP level applied, a constant proportion (approximately 50%) of measured PBLAD (in cm H2O) was reflected in PPLAT. A higher safety threshold for PPLAT should be considered in the setting of IAH/ACS as the clinician considers changes in VT. A strategy of reducing VT to cap PPLAT at widely recommended values may not be warranted in the setting of increased IAP.

Hemodynamic and related challenges: monitoring and regulation in the postoperative period

The clinician caring for patients in the immediate postoperative period must maintain a high index of suspicion for the development of complications. Evolving illness manifests itself throughout the continuum of care and must be recognized and aggressively managed to ensure optimal outcome. This article discusses common hemodynamic problems encountered in the postanesthesia care unit. These problems are presented in a clinical framework that is familiar to experienced practitioners and recognizable to trainees. This article reviews of these common problems including relevant physiologic principles; effects on hemodynamics; and a logical approach to evaluation, monitoring, and management of a complex postoperative patient.