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

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.

Abdominal compartment syndrome and intra-abdominal hypertension in critically ill patients: diagnostic value of computed tomography

AIMS

The aims of the present work were to reevaluate, prospectively, the diagnostic value of already-described computed tomography (CT) landmarks of intra-abdominal hypertension (IAH) and abdominal compartment syndrome (ACS) and to study the diagnostic value of some undescribed CT signs for the diagnosis of IAH and ACS.

MATERIALS AND METHODS

Consecutive patients admitted to the intensive care unit (ICU) in shock for whom an abdominal CT was clinically indicated were included. CT examinations were reviewed and scored by two reviewers for the 12 proposed CT features of IAH and ACS. Intravesical pressure (IVP) was measured for each patient. Imaging features and clinical data of patients with IAH (IVP ≥ 12 mmHg) were compared to those of patients with normal intra-abdominal pressure (IVP < 12 mmHg).

RESULTS

Forty-one patients were included. Twenty-one patients (51%) presented IAH with an IVP value ≥ 12 mmHg. Four patients (10%) were considered to have ACS (10%). Only an increased peritoneal-to-abdominal height ratio (PAR) was associated with the presence of IAH (PAR = 0.45 [0.40-0.49] in patients with IVP < 12 mmHg and PAR = 0.52 [0.48-0.53] in patients with IVP ≥ 12 mmHg; p < 0.001). Increased PAR ≥ 0.52 had a specificity of 85% for IAH diagnosis.

CONCLUSION

The present study suggests that a PAR ≥ 0.52 could help radiologists to identify IAH on abdominal CT scan and could lead to adequate identification and/or treatment, even at early stages of IAH.

KEY POINTS

• CT is an efficient first-intention procedure to evaluate and follow up underlying conditions in critically ill patients at risk of IAH and ACS overcome. • Raising the possibility of an IAH on a CT examination is relevant information for the clinician. • The only factors associated with intra-abdominal hypertension were the peritoneal-to-abdominal height ratio (PAR) and the ratio of maximal anteroposterior to transverse abdominal diameter (which define the round belly sign when > 0.8).

Comparison of pressure-regulated volume control ventilation and pressure control ventilation in patients with abdominal compartment syndrome

Mechanical ventilation support is commonly required in abdominal compartment syndrome (ACS). In the present study, pressure-regulated volume control ventilation (PRVCV) was compared to pressure control ventilation (PCV) in patients with ACS. The prospective study included 40 patients with ACS who were randomized into the PCV or PRVCV groups and subjected to the different modes of ventilation. After 6 h of ventilation, arterial blood gas, respiratory mechanics and hemodynamics parameters, as well as the intra-abdominal pressure (IAP) and Sequential Organ Failure Assessment (SOFA) scores were calculated. Compared to the PCV mode, mechanical ventilation with PRVCV lead to a significant decrease in the partial pressure of carbon dioxide, the peak inspiratory pressure, the mean inspiratory pressure, the central venous pressure, the heart rate and the extravascular lung water index. In addition, a marked improvement in pH, partial pressure of oxygen, oxygenation index and pulmonary static compliance was noted. However, no significant differences in airway resistance, mean arterial pressure, or IAP and SOFA scores were obtained. In conclusion, the PRVCV mode is better than the PCV mode in ventilation patients with ACS, and should therefore be used as a lung protective strategy. The present study was registered at Chictr.org (no. ChiCTR1800016869).

The Duration of Intra-abdominal Hypertension and Increased Serum Lactate Level are Important Prognostic Markers in Critically Ill Surgical Patient's Outcome: A Prospective, Observational Study

Aim:

The present study analyzed the clinical significance of duration of intra-abdominal hypertension (IAH) associated with increased serum lactate in critically ill patients with severe sepsis.

Materials and Methods:

Our study was an observational, prospective study carried out in the Surgical Intensive Care Unit (ICU) at J.L.N Medical College, Ajmer, Rajasthan, India. In our study, we included a total of 100 patients and intra-abdominal pressure (IAP) was measured through intravesical route at the time of admission and after 6, 12, 24, 48, and 72 h via a urinary catheter filled with 25 ml of saline. Duration of ICU and hospital stay, need for ventilator support, initiation of enteral feeding, serum lactate level at time of admission and after 48 h, and 30-day mortality were noted as outcomes.

Results:

In our study, an overall incidence of IAH was 60%. Patients with cardiovascular surgery and renal and pulmonary dysfunction were 93.3%, 55%, and 60%, respectively, at the time of admission and 65%, 10%, and 10%, respectively, after 72 h of admission in the surgical ICU. Nonsurvivors had statistically significant higher IAP and serum lactate levels than survivors. Patients with longer duration of IAH had longer ICU and hospital stay, longer duration of vasopressors and ventilator support, and delayed enteral feeding.

Conclusion:

There is a strong relationship “risk accumulation” between duration of IAH associated with increased serum lactate and organ dysfunction. The duration of IAH was an independent predictor of 30-day mortality. Early recognition and prompt intervention for IAH and severe sepsis are essential to improve the patient outcomes.