The role of Cushing's reflex and the vasopressin-mediated oligoanuric response to intracranial hypertension in patients with abdominal compartment syndrome.

BACKGROUND: We examined the link between increased intra-abdominal pressure, intracranial pressure, and vasopressin release as a potential mechanism. Intra-abdominal pressure, produced by abdominal-cavity insufflation with carbon dioxide (CO2) during laparoscopic abdominal procedures to facilitate visualization, is associated with various complications, including arterial hypertension and oliguria. METHODS: Mean arterial pressure, optic nerve sheath diameter, measured as a proxy for intracranial pressure, plasma vasopressin, serum and urine osmolarity, and urine output were measured 4 times during laparoscopic sleeve gastrectomy in 42 patients: before insufflation with CO2 (T0); after insufflation to 15 cm water (H2O) pressure, with 5 cm H2O positive end-expiratory pressure (T1); after positive end-expiratory pressure was raised to 10 cm H2O (T2); and after a return to the baseline state (T3). Mean values at T0 to T3 and the directional consistency of changes (increase/decrease/ unchanged) were compared among the 4 data-collection points. RESULTS: Statistically significant elevations (all P ≤ .001) were noted from T0 to T1 and from T0 to T2 in mean arterial pressure, optic nerve sheath diameter, and vasopressin, followed by decreases at T3. For optic nerve sheath diameter and vasopressin, the increases at T1 and T2 occurred in 98% and 100% of patients, ultimately exceeding normal levels in 88 and 97%, respectively. Conversely, urine output fell from T0 to T1 and T2 by 60.9 and 73.4%, decreasing in 88.1% of patients (all P < .001). Patients with class II obesity exhibited statistically greater increases in optic nerve sheath diameter and vasopressin, but statistically less impact on urine output, than patients with class III obesity. CONCLUSION: Increased mean arterial pressure, intracranial pressure, and vasopressin release appear to be intermediary steps between increased intra-abdominal pressure and oliguria. Further research is necessary to determine any causative links between these physiological changes.

[Intra-abdominal pressure measurement]. / Intraabdominelle Druckmessung ­ Schritt für Schritt.

An elevated intra-abdominal pressure (IAP) above 12 mmHg is a pathological finding in critically ill patients. IAP are classified into different degrees of intra-abdominal hypertension and, in the presence of associated organ failure, as abdominal compartment syndrome. Both disease entities represent an underestimated factor in intensive care patients and are associated with increased mortality and prolonged intensive care and hospital stay. The measurement of intra-abdominal pressure in critically ill patients in intensive care units is not widely established and there is often considerable uncertainty regarding measurement conditions and methods. If risk factors are present, intra-abdominal pressure should be monitored every 4 hours. Bladder pressure measurement is the gold standard for determining intra-abdominal pressure. The measurement is a non-invasive, cost-effective, easy to perform bedside and safe method for the patient.

Effect of intra-abdominal hypertension on the intraocular pressure of the conscious dogs.

This study was performed to evaluate the effect of intra-abdominal pressure (IAP) on intraocular pressure (IOP) in conscious dog models using a balloon technique to generate intra-abdominal hypertension. Six healthy dogs without ocular abnormalities were evaluated in this study. A balloon device was placed in the intra-abdominal cavity. The abdomen was insufflated to IAP levels of 15 and 25 mmHg using the balloon device. Intraocular pressure was measured at baseline, at IAP levels of 15 and 25 mmHg, and after decompression. In comparison with the mean baseline IOP (15.1 ± 2.0 mmHg), there was a significant increase in IOP at IAP levels of 15 mmHg (20.0 ± 2.1 mmHg) and 25 mmHg (19.9 ± 2.2 mmHg), corresponding to a 32.4% and 31.7% increase from baseline IOP, respectively. The mean IOP after decompression (14.8 ± 1.7 mmHg) was significantly lower compared to those at IAP levels of 15 and 25 mmHg. The present findings demonstrate that increased IAP has a clinically significant effect on IOP in dogs under conscious conditions. Although more research is needed to determine of increased IAP on IOP, these findings suggest that increased IAP leads to mild and reversible increase in IOP.

Reliability of Pulse Contour Cardiac Output Analysis in a Piglet Model of Multi-step Intra-abdominal Hypertension.

BACKGROUND: Pulse contour cardiac output (PCCO) analysis is a minimally invasive technique for continuous cardiac output (CO) measurement monitoring. PCCO requires calibration by transpulmonary thermodilution (TPTD). Studies showed good agreement between PCCO, TPTD CO and CO measured by pulmonary artery thermodilution (PATD) during stable hemodynamics. However, data are limited in patients with intra-abdominal hypertension (IAH). The objective is to compare the agreement between PCCO, TPTD CO, and PATD CO in a piglet model of multi-step IAH. MATERIALS AND METHODS: Ten female domestic piglets were enrolled in this study. IAH was induced by stepwise carbon dioxide inflation into peritoneal cavity in anesthetized piglets. Following baseline registrations, intra-abdominal pressure (IAP) was increased and maintained at each IAP plateau of 10, 20, 30, and 40 mmHg for 15 min before CO measurements. CO was measured by PATD and simultaneously by 2 femoral artery PCCO catheters. One PCCO catheter was recalibrated by TPTD at each IAP plateau while the other was only calibrated at baseline. RESULTS: In pooled data of different IAP stages, TPTD CO and recalibrated PCCO (R-PCCO) showed excellent correlation (r2 = 0.94 and 0.93) and small bias (-0.09 and -0.09 L/min), respectively, compared with PATD CO. However, PCCO without recalibration (NR-PCCO) were not accurate during IAH (r2 = 0.58, bias: +0.32 L/min). When IAP increased to 30 mmHg, NR-PCCO failed to agree with PATD CO (r2 = 0.47, bias: +0.52 L/min). On the contrary, a clinically accepted agreement between TPTD CO, R-PCCO, and PATD CO was observed at different IAP stages. CONCLUSIONS: TPTD CO and R-PCCO agreed with PATD CO in this piglet model of multi-step IAH. On the contrary, NR-PCCO failed to agree with PATD CO when IAP increased to 30 mmHg or more. PCCO analysis needs recalibration in this condition.

Do we have the guts to go? The abdominal compartment, intra-abdominal hypertension, the human microbiome and exploration class space missions.

Humans are destined to explore space, yet critical illness and injury may be catastrophically limiting for extraterrestrial travel. Humans are superorganisms living in symbiosis with their microbiomes, whose genetic diversity dwarfs that of humans. Symbiosis is critical and imbalances are associated with disease, occurring within hours of serious illness and injury. There are many characteristics of space flight that negatively influence the microbiome, especially deep space itself, with its increased radiation and absence of gravity. Prolonged weightlessness causes many physiologic changes that are detrimental; some resemble aging and will adversely affect the ability to tolerate critical illness or injury and subsequent treatment. Critical illness-induced intra-abdominal hypertension (IAH) may induce malperfusion of both the viscera and microbiome, with potentially catastrophic effects. Evidence from animal models confirms profound IAH effects on the gut, namely ischemia and disruption of barrier function, mechanistically linking IAH to resultant organ dysfunction. Therefore, a pathologic dysbiome, space-induced immune dysfunction and a diminished cardiorespiratory reserve with exacerbated susceptibility to IAH, imply that a space-deconditioned astronaut will be vulnerable to IAH-induced gut malperfusion. This sets the stage for severe gut ischemia and massive biomediator generation in an astronaut with reduced cardiorespiratory/immunological capacity. Fortunately, experiments in weightless analogue environments suggest that IAH may be ameliorated by conformational abdominal wall changes and a resetting of thoracoabdominal mechanics. Thus, review of the interactions of physiologic changes with prolonged weightlessness and IAH is required to identify appropriate questions for planning exploration class space surgical care.

L'humanité est à l'aube d'une nouvelle ère d'exploration spatiale, mais le risque de maladies et blessures graves pourrait restreindre de manière catastrophique le potentiel des voyages dans l'espace. L'être humain est un superorganisme vivant en symbiose avec son microbiote, dont la diversité génétique éclipse celle de l'hôte. Cette symbiose est essentielle : tout déséquilibre est associé à une dégradation de l'état de santé dans les heures suivant l'occurrence d'une blessure ou d'une maladie grave. Bon nombre de caractéristiques propres au vol spatial ont des répercussions négatives sur le microbiote; l'espace lointain présente des dangers particuliers en raison de l'exposition accrue au rayonnement et de l'absence de gravité. L'exposition prolongée à l'apesanteur cause une myriade de changements physiologiques nuisant à la santé. Certains ressemblent à des processus de vieillissement et réduiront la capacité à tolérer une blessure ou une maladie grave et son traitement. L'hypertension intra-abdominale (HIA) causée par une maladie grave peut réduire la perfusion des viscères et du microbiote, ce qui peut avoir des conséquences catastrophiques. Des études sur modèle animal ont confirmé les effets profondément délétères de l'HIA sur les intestins par l'apparition d'une ischémie et une altération de la barrière intestinale; cette découverte permettrait d'établir un lien mécanistique entre l'HIA et la défaillance d'organes résultante. Par conséquent, une dysbiose pathologique, associée à un dysfonctionnement immunitaire en apesanteur et à une réduction de la réserve cardiorespiratoire accompagnée d'une exacerbation de la susceptibilité à l'HIA, pourrait signifier qu'un astronaute exposé à l'effet déconditionnant de l'apesanteur serait vulnérable aux problèmes de perfusion de l'intestin découlant de l'HIA. Ce problème pourrait à son tour mener à une ischémie intestinale grave et à une production massive de biomédiateurs chez un astronaute présentant déjà une capacité cardiorespiratoire et immunitaire réduite. Heureusement, des expériences dans des environnements simulant l'apesanteur semblent indiquer que les effets de l'HIA pourraient être contrés par des changements conformationnels de la paroi abdominale et un rétablissement de la mécanique thoracoabdominale. Par conséquent, un examen des interactions des changements physiologiques associés à un état d'apesanteur prolongé et à l'HIA est requis pour déterminer les questions à poser afin de planifier adéquatement les soins chirurgicaux en contexte d'exploration spatiale.

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

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

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

Successful intraoperative management in patients with abdominal compartment syndrome induced by giant liposarcomas: Two case reports.

RATIONALE: Giant intra-abdominal liposarcomas weighing over 20 kg often increase the intra-abdominal pressure (IAP), which has severe effects on the cardiovascular and respiratory systems. Abdominal compartment syndrome is defined typically as the combination of a raised IAP of 20 mm Hg or higher and new onset of organ dysfunction or failure. The anesthetic management and perioperative management are very challenging. PATIENTS CONCERNS: We presented 2 patients with rare giant growing liposarcoma of the abdomen, weighing 21 kg and over 35 kg, respectively. Circulatory management was particularly difficult in the first case, while respiratory management and massive blood loss was very challenging in the second one. DIAGNOSIS: With a computed tomography scan and peritoneal-to-abdominal height ratio measurement, preoperatively the risk of developing intra-abdominal hypertension and abdominal compartment syndrome was recognized early in each patient. The inferior vena cava and right atrium of the first patient was compressed and malformed due to the uplifted diaphragm, while there was severe decreased lung volume and increased airway resistance, because of rare giant retroperitoneal liposarcomas in the second case. Histologic examination revealed dedifferentiated liposarcoma in both cases. INTERVENTIONS: Both of the patients underwent resection surgery with multiple monitoring; transesophageal echocardiography monitoring in the first case and pressure-controlled ventilation volume guaranteed mechanical ventilation mode in both cases. OUTCOMES: Intraoperatively and postoperatively no cardiopulmonary complications in both patients. The first patient was discharged without any complications on postoperative day 10, and the second patient underwent another surgery because of anastomotic leakage resulting from bowel resection. LESSONS: Multiple monitorings, in particular transesophageal echocardiography should be considered in patients with increased IAP due to a giant mass, while an appropriate lung protection ventilation strategy is crucial in these patients.

Evaluation of the effects of intraabdominal hypertension on equine central venous pressure.

OBJECTIVE: To evaluate the effect of changes in intraabdominal pressure (IAP) on central venous pressure (CVP) in normal horses. DESIGN: Experimental, in vivo study. SETTING: University Teaching Hospital. ANIMALS: Convenience sample of 7 mixed breed horses-5 geldings and 2 mares. INTERVENTIONS: Pneumoperitoneum was induced in horses under standing sedation with carbon dioxide gas using a laparoscopic insufflator for a total of 60 minutes to simulate clinical elevation in IAP. Pressure was increased stepwise to 20 mm Hg over 30 minutes, and maintained at that pressure for 30 minutes to evaluate the effect of sustained intraabdominal hypertension. CVP was obtained from the cranial vena cava, concurrent with pressure obtained from the peritoneal cavity. MEASUREMENTS AND MAIN RESULTS: CVP increased as IAP increased up to 12 mm Hg, and declined as IAP increased further. The changes in CVP over time were significantly different (P < 0.03). Repeated measures correlation was positive, and highest, for mean CVP as IAP increased from 0 to 12 mm Hg (r = .70; 95% CI, .43-.85; P < 0.0001). Correlation of mean CVP with insufflation pressure became negative as IAP increased further from 15 to 20 mm Hg (r = -.47; 95% CI, -.66 to -.21; P = 0.0006). CONCLUSIONS: This report provides preliminary data demonstrating a biphasic trend in equine CVP caused by changes in IAP, similar to that observed in other species. Further investigations are needed to evaluate this trend and to confirm these results in clinical patients.

Intravesical monitoring of intra-abdominal pressure after renal transplantation in children: A safety and feasibility study.

IAH after RTX can threaten graft viability. This study aimed to assess the feasibility and safety of longitudinal IAP measurements as an IAH screening method in children after RTX. A cohort of eight children with a mean ± SD [range] age 9.6 ± 6.2 [2-17] years who underwent RTX and 18 control patients were evaluated between May 2017 and February 2018. We compared longitudinal IAP measurements using a Foley manometer to other clinical monitoring data. In total, 29 IAP measurements were performed in RTX patients and 121 in controls. The mean post-operative IAP was 7.4 ± 4.3 [1-16] mm Hg following RTX and 8.1 ± 3.7 [1-19] mm Hg in controls. We noted IAH in 9 (31%) of 29 IAP measurements after RTX and in 41 (34%) of 121 IAP measurements in controls. No graft dysfunction occurred in RTX patients despite elevated IAP values. The mean ± SD [range] time expenditure for IAP measurement was 2.1 ± 0.4 [0.6-3.2] minutes. No severe complications occurred during the IAP measurements. Analysis of longitudinal IAP measurements demonstrated that IAP measurement is safe and feasible in children recovering from renal transplantation in the PICU.

Intra-abdominal hypertension as a trigger of "gut failure" in SARS-CoV-2 infection: Effect of open abdomen (OA) and negative pressure therapy (NPT) on respiratory and gastrointestinal (GI) function.

COVID-19 gastrointestinal manifestations could be attributed to SARS-CoV-2-induced small vessel thrombosis. OA with NPT treatment may have a role in optimization of bowel microcirculation and in the reduction of the endothelial and the systemic cytokine-related damage, improving also respiratory function.

Role of Static and Dynamic Intra-abdominal Pressure Monitoring in Acute Pancreatitis: A Prospective Study on Its Impact.

OBJECTIVE: This study was aimed to determine the relationship between static and dynamic intra-abdominal pressure (IAP) with the mortality and outcome of acute pancreatitis. METHODS: From July 2017 to December 2018, 150 patients admitted at the Institute of Gastrosciences and Liver and diagnosed as acute pancreatitis were included in the study. Intra-abdominal pressure was measured for the first few days, and mean value of day 1 (static IAP) and highest value on day 2 and day 3 (dynamic IAP) were calculated and categorized into intra-abdominal hypertension and abdominal compartment syndrome. RESULTS: A statistical relationship was observed between static and dynamic IAP with the severity and mortality of acute pancreatitis. Both static and dynamic IAPs tended to be higher in nonsurvivors (83.33% and 88.88%, respectively) compared with survivors (51.51% and 63.63%, respectively). Higher IAP had more severe disease. However, IAP did not correlate with the evidence of sepsis or serum procalcitonin levels. CONCLUSION: Determination of static IAP is an easy, useful, and inexpensive method to determine and predict the mortality of acute pancreatitis. Prevention and/or early detection of intra-abdominal hypertension helps in reducing the mortality in acute pancreatitis.

The Correlation of Intraabdominal Pressure With Renal Resistive Index.

BACKGROUND: To evaluate the correlation between intraabdominal pressure (IAP) measured via the bladder and renal resistive index (RRI) measured by Doppler ultrasonography (USG). METHODS: Eighty consecutive surgical patients were included into this study. Before Doppler USG evaluation, IAP was measured by a Foley catheter via the bladder. The left and right RRI, the diameters of the inferior vena cava and portal vein were measured by colored Doppler USG. Spearman correlation analysis was used to evaluate the correlation between different measurements. Intraabdominal hypertension (IAH) was defined as of IAP ≥ 12 mmHg. Significantly different variables from the univariate analysis between patients with and without IAH were entered into backward stepwise binary logistic regression analysis of IAH as the dependent variable. P values < 0.05 were accepted as statistically significant. RESULTS: In total, 80 patients were included into study. In 27 patients (34%) IAP was normal and in 53 patients (66%) IAH was diagnosed. The Spearman correlation analysis of IAP and the ultrasonographic measurements revealed a strong correlation between RRI and IAP (P < 0.001). Patients with IAH were more likely to be diabetic and had abdominal incisional hernia compared with patients with normal IAP (P < 0.05). The results of the multivariate logistic regression analysis revealed right RRI as the only independent predictor of IAH (B: 57.04, S. E.: 13.7, P < 0.001). CONCLUSIONS: There is a strong correlation between IAP and RRI. RRI can be an alternative, noninvasive technique for the diagnosis and follow-up of IAH after further evaluations in different patient groups.

A Clinician's Guide to Management of Intra-abdominal Hypertension and Abdominal Compartment Syndrome in Critically Ill Patients.

This article is one of ten reviews selected from the Annual Update in Intensive Care and Emergency Medicine 2020. Other selected articles can be found online at https://www.biomedcentral.com/collections/annualupdate2020. Further information about the Annual Update in Intensive Care and Emergency Medicine is available from http://www.springer.com/series/8901.

Basic Fibroblast Growth Factor (bFGF) Protects the Blood-Brain Barrier by Binding of FGFR1 and Activating the ERK Signaling Pathway After Intra-Abdominal Hypertension and Traumatic Brain Injury.

BACKGROUND Intra-abdominal hypertension (IAH) is associated with high morbidity and mortality. IAH leads to intra-abdominal tissue damage and causes dysfunction in distal organs such as the brain. The effect of a combined injury due to IAH and traumatic brain injury (TBI) on the integrity of the blood-brain barrier (BBB) has not been investigated. MATERIAL AND METHODS Intracranial pressure (ICP) monitoring, brain water content, EB permeability detection, immunofluorescence staining, real-time PCR, and Western blot analysis were used to examine the effects of IAH and TBI on the BBB in rats, and to characterize the protective effects of basic fibroblast growth factor (bFGF) on combined injury-induced BBB damage. RESULTS Combined injury from IAH and TBI to the BBB resulted in brain edema and increased intracranial pressure. The effects of bFGF on alleviating the rat BBB injuries were determined, indicating that bFGF regulated the expression levels of the tight junction (TJ), adhesion junction (AJ), matrix metalloproteinase (MMP), and IL-1ß, as well as reduced BBB permeability, brain edema, and intracranial pressure. Moreover, the FGFR1 antagonist PD 173074 and the ERK antagonist PD 98059 decreased the protective effects of bFGF. CONCLUSIONS bFGF effectively protected the BBB from damage caused by combined injury from IAH and TBI, and binding of FGFR1 and activation of the ERK signaling pathway was involved in these effects.

Bench Validation of a Handcrafted Prototype Catheter for Intra-gastric Pressure Monitoring.

BACKGROUND: Abdominal compartment syndrome is a sustained intra-abdominal pressure (IAP) >20 mm Hg associated with new organ dysfunction. In order to prevent its development and related complications, IAP monitoring should be performed in patients with risk factors. Although techniques for its monitoring have been developed, they are of high cost and not always available in low- and lower-middle-income countries. Therefore, we aim to develop and validate in a bench model a handcrafted catheter to be used as an alternative method to measure the intra-gastric pressure (IGP) as a surrogate of the IAP. METHODS: We used an acrylic water container as a model of the abdomen and four handcrafted catheters made of a 16 Fr Levin tube with a globe finger tied with silk in the distal end, inflated with 1 cm of air. They were placed on the bottom of the container where the water pressure was directly measured as a gold standard. The agreement between the two measures was assessed with the Bland-Altman method. RESULTS: We performed 120 simultaneous measures. The mean pressure difference was 0.218 (95% CI 0.074 to 0.363). CONCLUSIONS: The handcrafted prototype catheter and the direct measure were highly correlated. The new catheter is a reliable and reproducible tool for pressure monitoring. However, before it can be used in the clinical setting for IAP monitoring, validation in human models in a real clinical setting needs to be performed.

Abdominal compartment syndrome: Often overlooked conditions in medical intensive care units.

Intra-abdominal hypertension (IAH) and abdominal compartment syndrome are well recognized entities among surgical patients. Nevertheless, a number of prospective and retrospective observational studies have shown that IAH is prevalent in about half of the critically ill patients in the medical intensive care units (ICU) and has been widely recognized as an independent risk factor for mortality. It is alarming to note that many members of the critical care team in medical ICU are not aware of the consequences of untreated IAH and the delay in making the diagnosis leads to increased morbidity and mortality. Frequently it is underdiagnosed and undertreated in this patient population. Elevated intra-abdominal pressure decreases the blood flow to the kidneys and other abdominal viscera and also results in reduced cardiac output and difficulties in ventilating the patient because of increased intrathoracic pressure. When intraabdominal hypertension is not promptly recognized and treated, it leads to abdominal compartment syndrome, multiorgan dysfunction syndrome and death. Large volume fluid resuscitation is very common in medical ICU patients presenting with sepsis, shock and other inflammatory conditions like pancreatitis and it is one of the major risk factors for the development of intra-abdominal hypertension. This article presents an overview of the epidemiology, definitions, risk factors, pathophysiology and management of IAH and abdominal compartment syndrome in critically ill medical ICU patients.

Intra-abdominal pressure may be elevated in patients with open abdomen after emergent laparotomy.

PURPOSE: To estimate the change in intra-abdominal pressure (IAP) among critically ill patient who were left with open abdomen and temporary abdominal closure after laparotomy, during the first 48 h after admission. METHODS: A cohort study in a single ICU in a tertiary care hospital. All adult patients admitted to the ICU after emergent laparotomy for acute abdomen or trauma, who were left with temporary abdominal closure (TAC), were included. Patients were followed up to 48 h. IAP was routinely measured at 0, 6, 12, 24, and 48 h after admission to ICU. RESULTS: Thirty-nine patients were included, 34 were operated due to acute abdomen and 5 due to abdominal trauma. Seventeen patients were treated with skin closure, 13 with Bogota bag, and 9 with negative pressure wound therapy (NPWT). Eleven patients (28.2%) had IAP of 15 mmHg or above at time 0, (mean pressure 19.0 ± 3.0 mmHg), and it dropped to 12 ± 4 mmHg within 48 h (p < 0.01). Reduction in lactate level (2.4 ± 1.0 to 1.2 ± 0.2 mmol/L, p < 0.01) and increase in PaO2/FiO2 ratio (163 ± 34 to 231 ± 83, p = 0.03) were observed as well after 48 h. CONCLUSIONS: This is the first large report of IAP in open abdomen. Elevated IAP may be measured in open abdomen and may subsequently relieve after 48 h.

The Cushing reflex and the vasopressin-mediated hemodynamic response to increased intracranial pressure during acute elevations in intraabdominal pressure.

BACKGROUND: Abdominal compartment syndrome has been linked to detrimental hemodynamic side effects that include increased intracranial pressure and diminished renal function, but the mechanisms behind this continue to be elucidated. In this study, we sought to investigate any direct association between acute elevations in intra-abdominal pressure and intracranial hypertension during experimentally induced abdominal compartment syndrome and between acutely elevated intracranial pressure and the hemodynamic response that might be elicited by a vasopressin-induced Cushing reflex affecting urine osmolality and urine output. The aim of this study is to explain the Cushing reflex and the vasopressin-mediated hemodynamic response to intracranial pressure during acute elevations in intra-abdominal pressure. METHODS: We measured intra-abdominal pressure, intrathoracic pressure, optic nerve sheath diameter as an indirect sign of intracranial pressure, vasopressin levels in blood, urine osmolality, and urine output at 4 time points during surgery in 16 patients undergoing sleeve gastrectomy for morbid obesity. Values for the 4 time points were compared by repeated-measures analysis of variance. RESULTS: More than 50-fold elevations in serum vasopressin paralleled increases in optic nerve sheath diameter, rising throughout prepneumoperitoneum and tapering off afterward, in conjunction with a marked decrease in urine but not serum osmolality. Mean arterial pressure rose transiently during pneumoperitoneum without elevated positive end-expiratory pressure but was not significantly elevated thereafter. CONCLUSIONS: These findings support our hypothesis that the oliguric response observed in abdominal compartment syndrome might be the result of the acutely elevated intra-abdominal pressure triggering increased intrathoracic pressure, decreased venous outflow from the central nervous system, increased intracranial pressure, and resultant vasopressin release via a Cushing reflex.