Inverted U-Shaped Relationship between Central Venous Pressure and Intra-Abdominal Pressure in the Early Phase of Severe Acute Pancreatitis: A Retrospective Study

<div><p>Objective</p><p>Many studies have indicated that intra-abdominal pressure (IAP) is positively correlated with central venous pressure (CVP) in severe cases. However, although elevated IAP is common in patients with severe acute pancreatitis (SAP), its relationship with CVP remains unclear. Our study aimed to investigate the association of IAP with CVP in early-phase SAP patients.</p><p>Methods</p><p>In total, 116 SAP patients were included in this retrospective study. On the first day of hospitalization, blood samples were collected for biochemical examination and cytokine concentration monitoring. Additionally, a urinary catheter and right subclavian vein catheter were inserted for IAP and CVP measurement, respectively. Other routine clinical data were also recorded.</p><p>Results</p><p>Within 24 hours after hospitalization, CVP fluctuated and increased with increasing IAP up to 15.7 mmHg (<i>P</i> = 0.054) but decreased with increasing IAP when the IAP was > 15.7 mmHg (<i>P</i> < 0.001). After adjusting for abdominal perfusion pressure (APP) and mean arterial pressure (MAP), a similar distribution was observed. An inverted U-shaped trend between IAP and CVP was also present in the groups classified according to the patient’s sex, local complications, ascites, and serum amylase levels.</p><p>Conclusions</p><p>CVP and IAP have an inverted U-shaped relationship, with a peak at an IAP of 15.7 mmHg in the early phase of SAP. After this peak, CVP decreases as IAP increases. These results have crucial implications for clinical fluid resuscitation in SAP patients. In particular, because one CVP value might be correlated with different IAP values in patients with the same CVP, the volume of fluid needed might be different.</p></div

Adjusted Effect of IAP on CVP [β (95%CI) <i>P</i> value].

<p>Outcome variance: CVP (cmH₂O); risk factor: IAP (mmHg).</p><p>Model I: Multiple regression model (no adjusted related risk factors);</p><p>Model II: Multiple regression model adjusted APP level;</p><p>Model III: Multiple regression model adjusted MAP level.</p><p>CVP: central venous pressure; IAP: intra abdominal pressure; MAP: mean arterial pressure; APP: abdominal perfusion pressure.</p><p>Adjusted Effect of IAP on CVP [β (95%CI) <i>P</i> value].</p

Characteristics of the study population by intra-abdomnal pressure quartiles.

<p>Q1: the patients with IAP≤15.7mmHg; Q2: the patients with IAP>15.7 mmHg.</p><p><i>P</i>: value from Kruskal Test (rank sum test);</p><p>*<i>P</i>: value from ANOVA.</p><p>RBC: count of red blood cell; APACHE II score: Acute Physiology and Chronic Health Evaluation II score; APP: abdominal perfusion pressure; MAP: mean arterial pressure.</p><p>[mean±SD or n(%)]</p><p>Characteristics of the study population by intra-abdomnal pressure quartiles.</p

Bar chart representing the frequency of different grades of IAH according to the World Society for Abdominal Compartment syndrome guidelines.

<p>Normal: IAP<12mmHg; GradeI IAH: IAP between 12 to 15 mmHg. GradeII IAH: IAP between 16 to 20 mmHg. GradeIII IAH: IAP between 21 to 25 mmHg. GradeIV IAH: IAP greater than 25 mmHg. IAP: intra-abdominal pressure, IAH: intra-abdominal hypertension.</p

Smoothing curve of CVP (cmH₂O) by IAP (mmHg) in different groups considering.

<p>A: patients' gender; B: local complication; C: ascites; D: serum amylase.</p

Characteristics of the study population by central venous pressure quartiles.

<p>CVP: central venous pressure; IAP: intra-abdominal pressure; MAP: mean arterial pressure; APP: abdominal perfusion pressure; HR: heart rate; Ascites: moderate-to-large fluid collections in the peritoneal cavity detected by B type ultrasonography or CT scans; APACHE II score: Acute Physiology and Chronic Health Evaluation II score; BE: base excess; CT grade: according to Balthazar's methods; Local complication: including pancreatic necrosis, pseudocyst and abscess.</p><p><i>P</i> value*: Kruskal Wallis rank sum test was used to examine the significance if the variable was continuous. If theoretical number of the enumeration data <10, Fisher's exact test was used to calculate the significance.</p><p>[mean (SD) and median (min-max) or n(%)]</p><p>Characteristics of the study population by central venous pressure quartiles.</p

Scatter plot and smoothing curve of IAP (mmHg) by CVP (cmH₂O).

<p>Scatter plot and smoothing curve of IAP (mmHg) by CVP (cmH₂O).</p