A Single-Lumen Central Venous Catheter for Continuous and Direct Intra-abdominal Pressure Measurement

Background: Abdominal compartment syndrome (ACS) is associated with high morbidity and mortality rates. Therefore, the need for a good diagnostic tool to predict intra-abdominal hypertension (IAH) and progression to ACS is paramount. Bladder pressure (BP) has been used for several years for intra-abdominal pressure (IAP) measurement but has the disadvantage that it is not a continuous measurement. In this study, a single-lumen central venous catheter (CVC) is placed through the abdominal wall into the abdominal cavity to continuously and directly monitor the intra-abdominal pressure (CDIAP). The aim of this study was to evaluate the use of CDIAP to measure BP as a representative of the true IAP. Methods: Both BP and CDIAP were prospectively recorded on a variety of surgical patients admitted to the intensive care unit (ICU) from March 2003 up to December 2004. At the end of the surgical procedure, the CVC was placed through the abdominal wall and connected to a pressure transducer. In addition, the BP was measured through the urine drainage port after clamping the catheter and filling the bladder with 50 ml of 0.9% saline. At least three paired measurements (BP and CDIAP) were performed for at least one day on the ICU in a standardized manner at preset time intervals on each patient. The paired measurements were compared using the Bland-Altman (B-A) method. Data are presented as mean ± standard deviation. Results: Over a period of 22 months (March 2003 until December 2004), 125 paired measurements of both BP and CDIAP were recorded on 25 patients. The mean age was 72.4 ± 6.6 years. Eighteen patients underwent central vascular surgery, and seven patients with peritonitis received laparotomy. The mean CDIAP was 11.4 ± 4.8 (range 2-30) mmHg, and the BP was 12.9 ± 5.3 (range 3-37) mmHg. The mean difference between CDIAP and BP was 1.6 ± 2.7 mmHg. There was an acceptable level of agreement (intraclass correlation 0.82) between IAP measured by BP and IAP measured via CDIAP. Conclusion: Continuous direct intra-abdominal pressure measurement proved that the BP measurement approach of Kron is representative of the IAP. CDIAP measurement is accurate and makes it easier for the nursing staff to be informed of the IAP

Intravenous fluid therapy for hospitalized and critically ill children: rationale, available drugs and possible side effects

Human beings are constituted mainly of water. In particular, children's total body water might reach 75-80% of their body weight, compared to 60-70% in adults. It is therefore not surprising, that children, especially hospitalized newborns and infants, are markedly prone to water and electrolyte imbalances. Parenteral fluid therapy is a cornerstone of medical treatment and is thus of exceptional relevance in this patient population. It is crucial to appreciate the fact that intravenous fluids are drugs with very different characteristics, different indications, contraindications and relevant side effects. In the present review, we will summarize the physiology and pathophysiology of water and electrolyte balance, underlining the importance and high prevalence of non-osmotic antidiuretic hormone release in hospitalized and critically ill children. Furthermore, we will discuss the characteristics and potential side effects of available crystalloids for the paediatric population, making a clear distinction between fluids that are hypotonic or isotonic as compared to normal plasma. Finally, we will review the current clinical practice regarding the use of different parenteral fluids in children, outlining both the current consensus on fluids employed for resuscitation and replacement and the ongoing debate concerning parenteral maintenance fluids

Early enteral nutrition in critically ill patients: ESICM clinical practice guidelines.

To provide evidence-based guidelines for early enteral nutrition (EEN) during critical illness. We aimed to compare EEN vs. early parenteral nutrition (PN) and vs. delayed EN. We defined "early" EN as EN started within 48 h independent of type or amount. We listed, a priori, conditions in which EN is often delayed, and performed systematic reviews in 24 such subtopics. If sufficient evidence was available, we performed meta-analyses; if not, we qualitatively summarized the evidence and based our recommendations on expert opinion. We used the GRADE approach for guideline development. The final recommendations were compiled via Delphi rounds. We formulated 17 recommendations favouring initiation of EEN and seven recommendations favouring delaying EN. We performed five meta-analyses: in unselected critically ill patients, and specifically in traumatic brain injury, severe acute pancreatitis, gastrointestinal (GI) surgery and abdominal trauma. EEN reduced infectious complications in unselected critically ill patients, in patients with severe acute pancreatitis, and after GI surgery. We did not detect any evidence of superiority for early PN or delayed EN over EEN. All recommendations are weak because of the low quality of evidence, with several based only on expert opinion. We suggest using EEN in the majority of critically ill under certain precautions. In the absence of evidence, we suggest delaying EN in critically ill patients with uncontrolled shock, uncontrolled hypoxaemia and acidosis, uncontrolled upper GI bleeding, gastric aspirate >500 ml/6 h, bowel ischaemia, bowel obstruction, abdominal compartment syndrome, and high-output fistula without distal feeding access

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

Increased intra-abdominal pressure (IAP) is common in intensive care patients, affecting aerated lung volume distribution. The current study deals with the effect of increased IAP and decompressive laparotomy on aerated lung volume distribution. The serial whole-lung computed tomography scans of 16 patients with increased IAP were retrospectively analyzed between July 2006 and July 2008 and compared to controls. The IAP increased from (12.1±2.3) mmHg on admission to (25.2±3.6) mmHg (P<0.01) before decompressive laparotomy and decreased to (14.7±2.8) mmHg after decompressive laparotomy. Mean time from admission to decompressive laparotomy and length of intensive-care unit (ICU) stay were 26 h and 16.2 d, respectively. The percentage of normally aerated lung volume on admission was significantly lower than that of controls (P<0.01). Prior to decompressive laparotomy, the total lung volume and percentage of normally aerated lung were significantly less in patients compared to controls (P<0.01), and the absolute volume of non-aerated lung and percentage of non-aerated lung were significantly higher in patients (P<0.01). Peak inspiratory pressure, partial pressure of carbon dioxide in arterial blood, and central venous pressure were higher in patients, while the ratio of partial pressure of arterial O2 to the fraction of inspired O2 (PaO2/FIO2) was decreased relative to controls prior to laparotomy. An approximately 1.8 cm greater cranial displacement of the diaphragm in patients versus controls was observed before laparotomy. The sagittal diameter of the lung at the T6 level was significantly increased compared to controls on admission (P<0.01). After laparotomy, the volume and percentage of non-aerated lung decreased significantly while the percentage of normally aerated lung volume increased significantly (P<0.01). In conclusion, increased IAP decreases total lung volume while increasing non-aerated lung volume. Decompressive laparotomy is associated with resolution of these effects on lung volumes

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

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

What is normal intra-abdominal pressure and how is it affected by positioning, body mass and positive end-expiratory pressure?

To describe what is defined as normal intra-abdominal pressure (IAP) and how body positioning, body mass index (BMI) and positive end-expiratory pressure (PEEP) affect IAP monitoring. A review of different databases was made (Pubmed, MEDLINE (January 1966-June 2007) and EMBASE.com (January 1966-June 2007)) using the search terms of "IAP", "intra-abdominal hypertension" (IAH), "abdominal compartment syndrome" (ACS), "body positioning", "prone positioning", "PEEP" and "acute respiratory distress syndrome" (ARDS). Prior to 1966, we selected older articles by looking at the reference lists displayed in the more recent papers. This review focuses on the concept that the abdomen truly behaves as a hydraulic system. The definitions of a normal IAP in the general patient population and morbidly obese patients are reviewed. Subsequently, factors that affect the accuracy of IAP monitoring, i.e., body position (head of bed elevation, lateral decubitus and prone position) and PEEP, are explored. The abdomen behaves as a hydraulic system with a normal IAP of about 5-7 mmHg, and with higher baseline levels in morbidly obese patients of about 9-14 mmHg. Measuring IAP via the bladder in the supine position is still the accepted standard method, but in patients in the semi-recumbent position (head of the bed elevated to 30A degrees and 45A degrees), the IAP on average is 4 and 9 mmHg, respectively, higher. Future research should be focused on developing and validating predictive equations to correct for supine IAP towards the semi-recumbent position. Small increases in IAP in stable patients without IAH, turned prone, have no detrimental effects. The role of prone positioning in the unstable patient with or without IAH still needs to be established