Urinary catheter monitoring of intra-abdominal pressure after major abdominal surgery, a cost-benefit analysis.

OBJECTIVE: To estimate costs and benefits associated with measurement of intra-abdominal pressure (IAP). METHODS: We built a cost-benefit analysis from the hospital facility perspective and time horizon limited to hospitalization for patients undergoing major abdominal surgery for the intervention of urinary catheter monitoring of IAP. We used real-world data estimating the likelihood of intra-abdominal hypertension (IAH), abdominal compartment syndrome (ACS), and acute kidney injury (AKI) requiring renal replacement therapy (RRT). Costs included catheter costs (estimated $200), costs of additional intensive care unit (ICU) days from IAH and ACS, and costs of CRRT. We took the preventability of IAH/ACS given early detection from a trial of non-surgical interventions in IAH. We evaluated uncertainty through probabilistic sensitivity analysis and the effect of individual model parameters on the primary outcome of cost savings through one-way sensitivity analysis. RESULTS: In the base case, urinary catheter monitoring of IAP in the perioperative period of major abdominal surgery had 81% fewer cases of IAH of any grade, 64% fewer cases of AKI, and 96% fewer cases of ACS. Patients had 1.5 fewer ICU days attributable to IAH (intervention 1.6 days vs. control of 3.1 days) and a total average cost reduction of $10,468 (intervention $10,809, controls $21,277). In Monte Carlo simulation, 86% of 1,000 replications were cost-saving, for a mean cost savings of $10,349 (95% UCI $8,978, $11,720) attributable to real-time urinary catheter monitoring of intra-abdominal pressure. One-way factor analysis showed the pre-test probability of IAH had the largest effect on cost savings and the intervention was cost-neutral at a prevention rate as low as 2%. CONCLUSIONS: In a cost-benefit model using real-world data, the potential average in-hospital cost savings for urinary catheter monitoring of IAP for early detection and prevention of IAH, ACS, and AKI far exceed the cost of the catheter.

Intra-abdominal hypertension and abdominal compartment syndrome: a current review.

PURPOSE OF REVIEW: Intra-abdominal hypertension (IAH) and its deleterious effects are present in at least one-third of ICU patients. Increased recognition of IAH has led to significant reduction in the incidence of abdominal compartment syndrome (ACS). Many questions remain regarding what therapeutic interventions truly reduce morbidity and mortality associated with IAH/ACS. Recent research sheds new light on the effects of IAH in individual organ systems and unique disease states. This paper will review recent research in IAH/ACS recognition, treatment, and management. RECENT FINDINGS: Recent research on IAH/ACS includes an improved understanding of the prevalence of IAH/ACS and confirmation of its independent association with organ failure. Specifically, new research adds clarity to the effects of IAH/ACS on individual organ systems and specific disease states. These results combine to improve the clinical ability to diagnose, monitor, and treat IAH/ACS. SUMMARY: There is significant research on the broad impact of IAH/ACS in the ICU setting. Focus on IAH/ACS has gone beyond the purview of intensivists and surgeons to include outstanding work by specialists in multiple sub-specialties. These advances have generated improvements in current treatment algorithms. We review recent IAH/ACS literature and have categorized the most pertinent results into organ system-specific contributions.

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.

Incidence, Risk Factors, and Outcomes of Intra-Abdominal Hypertension in Critically Ill Patients-A Prospective Multicenter Study (IROI Study).

OBJECTIVES: To identify the prevalence, risk factors, and outcomes of intra-abdominal hypertension in a mixed multicenter ICU population. DESIGN: Prospective observational study. SETTING: Fifteen ICUs worldwide. PATIENTS: Consecutive adult ICU patients with a bladder catheter. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Four hundred ninety-one patients were included. Intra-abdominal pressure was measured a minimum of every 8 hours. Subjects with a mean intra-abdominal pressure equal to or greater than 12 mm Hg were defined as having intra-abdominal hypertension. Intra-abdominal hypertension was present in 34.0% of the patients on the day of ICU admission (159/467) and in 48.9% of the patients (240/491) during the observation period. The severity of intra-abdominal hypertension was as follows: grade I, 47.5%; grade II, 36.6%; grade III, 11.7%; and grade IV, 4.2%. The severity of intra-abdominal hypertension during the first 2 weeks of the ICU stay was identified as an independent predictor of 28- and 90-day mortality, whereas the presence of intra-abdominal hypertension on the day of ICU admission did not predict mortality. Body mass index, Acute Physiology and Chronic Health Evaluation II score greater than or equal to 18, presence of abdominal distension, absence of bowel sounds, and positive end-expiratory pressure greater than or equal to 7 cm H2O were independently associated with the development of intra-abdominal hypertension at any time during the observation period. In subjects without intra-abdominal hypertension on day 1, body mass index combined with daily positive fluid balance and positive end-expiratory pressure greater than or equal to 7 cm H2O (as documented on the day before intra-abdominal hypertension occurred) were associated with the development of intra-abdominal hypertension during the first week in the ICU. CONCLUSIONS: In our mixed ICU patient cohort, intra-abdominal hypertension occurred in almost half of all subjects and was twice as prevalent in mechanically ventilated patients as in spontaneously breathing patients. Presence and severity of intra-abdominal hypertension during the observation period significantly and independently increased 28- and 90-day mortality. Five admission day variables were independently associated with the presence or development of intra-abdominal hypertension. Positive fluid balance was associated with the development of intra-abdominal hypertension after day 1.

Management of abdominal sepsis--a paradigm shift?

The abdomen is the second most common source of sepsis and secondary peritonitis. The most common causes of abdominal sepsis are perforation, ischemic necrosis or penetrating injury to the abdominal viscera. Management consists of control of the infection source, restoration of gastrointestinal tract (GI) function, systemic antimicrobial therapy and support of organ function. Mortality after secondary peritonitis is still high. Excluding patient-related factors such as age or co-morbidities that can not be influenced at the time of intervention, delay to surgical intervention and inability to obtain source control are the main determinants of outcome. In patients with severe physiological derangement or difficult intraperitoneal conditions, where a prolonged operation and complete anatomical repair may not be possible or appropriate, it is becoming increasingly popular to utilize a damage control strategy with abbreviated laparotomy and planned reoperations. The main components of damage control laparotomy for secondary peritonitis are postponing the reconstruction of intestinal anastomoses to a second operation (deferred anastomosis) and leaving the abdomen open with some form of temporary abdominal closure (TAC). Advances in the management techniques of the open abdomen and new negative pressure-based TAC-devices have significantly reduced the previously observed prohibitive morbidity associated with open abdomens. These advancements have led to current fascial closure rates after TAC approaching 90%. The cornerstones of appropriate antimicrobial therapy are the timing, spectrum and dosing of antibiotics. Enteral nutrition should be started as soon as possible in hemodynamically stable patients but withheld when the patient is on a significant dose of vasopressors or whenever GI hypoperfusion is suspected. Timely source control with appropriate use of antimicrobial agents and early intensive care offers the best chance of survival for patients with abdominal sepsis. The introduction of the concept of damage control to the management of secondary peritonitis represents a paradigm shift in the same way as in management of major trauma. Although limited and repeated surgical interventions have been shown to be safe, the actual benefits need to be demonstrated in controlled studies.

Propofol is associated with favorable outcomes compared with benzodiazepines in ventilated intensive care unit patients.

RATIONALE: Mechanically ventilated intensive care unit (ICU) patients are frequently managed using a continuous-infusion sedative. Although recent guidelines suggest avoiding benzodiazepines for sedation, this class of drugs is still widely used. There are limited data comparing sedative agents in terms of clinical outcomes in an ICU setting. OBJECTIVES: Comparison of propofol to midazolam and lorazepam in adult ICU patients. METHODS: Data were obtained from a multicenter ICU database (2003-2009). Patient selection criteria included age greater than or equal to 18 years, single ICU admission with single ventilation event (>48 h), and treatment with continuously infused sedation (propofol, midazolam, or lorazepam). Propensity score analysis (1:1) was used and mortality measured. Cumulative incidence and competing risk methodology were used to examine time to ICU discharge and ventilator removal. MEASUREMENTS AND MAIN RESULTS: There were 2,250 propofol-midazolam and 1,054 propofol-lorazepam matched patients. Hospital mortality was statistically lower in propofol-treated patients as compared with midazolam- or lorazepam-treated patients (risk ratio, 0.76; 95% confidence interval [CI], 0.69-0.82 and risk ratio, 0.78; 95% CI, 0.68-0.89, respectively). Competing risk analysis for 28-day ICU time period showed that propofol-treated patients had a statistically higher probability for ICU discharge (78.9% vs. 69.5%; 79.2% vs. 71.9%; P < 0.001) and earlier removal from the ventilator (84.4% vs. 75.1%; 84.3% vs. 78.8%; P < 0.001) when compared with midazolam- and lorazepam-treated patients, respectively. CONCLUSIONS: In this large, propensity-matched ICU population, patients treated with propofol had a reduced risk of mortality and had both an increased likelihood of earlier ICU discharge and earlier discontinuation of mechanical ventilation.

Safe, timely, convenient, and cost-effective: a single-center experience with bedside placement of enteral feeding tubes by midlevel providers using fluoroscopic guidance.

BACKGROUND: Enteral feeding tube placement has been performed by nurses, gastroenterologists using endoscopy, and interventional radiologists. We hypothesized that midlevel providers placed feeding tubes at bedside using fluoroscopy safely, rapidly, and cost-effectively. METHODS: We retrospectively analyzed bedside feeding tube placement under fluoroscopy by trained nurse practitioners. We compared charges for this method with charges for placement by other practitioners. RESULTS: Nurse practitioners placed 632 feeding tubes in 462 patients. Three hundred seventy-nine placements took place in mechanically ventilated placements. Ninety-seven percent of tubes were positioned past the pylorus. The mean fluoroscopy time was 0.7 ± 1.2 minutes. The mean procedure time was 7.0 ± 5.1 minutes. All tubes were placed within 24 hours of the request. There were no complications. Institutional charges for tube placement were $149 for nurse practitioners, $226 for gastroenterologists, and $328 for interventional radiologists. CONCLUSIONS: The placement of feeding tubes under fluoroscopy by nurse practitioners is safe, timely, and cost-effective.

Implementation of an enoxaparin protocol for venous thromboembolism prophylaxis in obese surgical intensive care unit patients.

BACKGROUND: Venous thromboembolism (VTE) is a serious health care issue that affects a large number of people. Few standards exist for delineating the optimal dosing strategy for VTE prevention in obese patients, especially in the setting of major surgery or trauma. OBJECTIVE: To document the efficacy of a surgical intensive care unit (SICU)-specific, weight-based dosing protocol of enoxaparin 0.5 mg/kg given subcutaneously every 12 hours for VTE prophylaxis in morbidly obese (defined as body mass index [BMI] ≥35 kg/m(2) or weight ≥150 kg) SICU patients, using peak anti-factor Xa levels to determine therapeutic endpoints. METHODS: Data were collected retrospectively in an academic, university-based SICU on 23 morbidly obese patients who received weight-based enoxaparin for VTE prophylaxis from December 1, 2008, through June 30, 2010. RESULTS: A weight-based dosage range of enoxaparin 50-120 mg twice daily (median 60) was given to 23 patients. The mean BMI was 46.4 kg/m(2). The initial mean anti-factor Xa level (measured after the third dose) was 0.34 IU/mL (range 0.20-0.59). Patients received an average of 18 doses. Two cases required an increase or decrease in dosage based on anti-factor Xa levels. Morbidity related to this dosing included a single event of minor endotracheal bleeding and a single deep vein thrombosis that was likely present prior to treatment. CONCLUSIONS: Weight-based dosing with enoxaparin in morbidly obese SICU patients was effective in achieving anti-factor Xa levels within the appropriate prophylactic range. This regimen reduced the rate of VTE below expected levels and no additional adverse effects were reported.

Delayed abdominal closure in the management of ruptured abdominal aortic aneurysm.

The objective of this study was to compare initial use of the open abdomen using the vacuum-pack technique followed by delayed abdominal closure with standard primary abdominal closure in the treatment of ruptured abdominal aortic aneurysm (rAAA) repair. A retrospective review identified 122 rAAA cases, which were divided into two management eras: era 1 (primarily closed) and era 2 (47% open abdomen).One hundred three patients were included in this review: 58 in era 1 and 45 in era 2. Evidence of one of three ischemia-reperfusion (IR) criteria, preoperative hypotension, estimated blood loss > or = 6 L, or intraoperative resuscitation with > or = 12 L, predicted mortality. These criteria were also used as surrogate clinical markers for abdominal compartment syndrome. The in-hospital mortality was higher in those with at least one IR criterion: 43% versus 10% (p = .0003). In those with at least one IR criterion, the initial 24-hour mortality was 21% for era 1 versus 0% for era 2 (p = .03), and the 30-day mortality was 40% for era 1 and 32% for era 2 (p = .77).Three IR criteria were identified and were associated with increased mortality. Patients with these risk factors who were treated with delayed abdominal closure had an improved acute survival rate and a trend for improved long-term survival.

A comparison of infusion volumes in the measurement of intra-abdominal pressure.

Bladder pressure measurement through a foley catheter is the current standard in monitoring for intraabdominal hypertension (IAH) and abdominal compartment syndrome (ACS). Accurate pressure transduction requires a continuous fluid column with a small volume of transducing medium at the tip of the catheter. Infusing excessive fluid volume can falsely elevate the measured intra-abdominal pressure (IAP) due to bladder overdistention and can lead to intrinsic muscular contraction. This effect can be seen with volumes as low as 60 mL. Recent expert consensus has recommended 25 mL as the maximal infusion volume; however, 50 mL is the most commonly cited volume of infusion in the literature. The purpose of this analysis was to determine the variance between IAP values using a range of volume infusions between 10 and 60 mL. Eighteen adult, surgical intensive care unit (SICU) patients who were undergoing IAP measurement for IAH or clinically indicated monitoring were enrolled in a prospective, nontreatment study. Intra-abdominal pressure measurements were obtained with stepwise increases of injectate volume from 10 to 60 mL (in 10 mL increments). Bland-Altman analyses and receiver operating characteristic (ROC) curves were used for analysis. After analysis accounting for data correlation within patients, means and standard deviations were generated for differences between 50 mL and 10, 20, 30, 40, and 60 mL bladder infusion volumes. Bland-Altman analyses showed good agreement between measurements and no significant difference in variance (mean < or =1.35 mm Hg) between volume comparisons. The ROC curve generated for each test volume using a diagnostic pressure value for IAH (!12 mm Hg) showed that a value between 11 and 12 mm Hg gave the best combination of sensitivity and specificity for all test volumes. In SICU patients, with a clinical indication for IAP monitoring, bladder infusion volumes between 10 mL and 60 mL provide consistent IAP measurements.

Reproducibility of bladder pressure measurements in critically ill patients.

OBJECTIVE: Intra-abdominal hypertension is an independent cause of multiorgan failure and directly effects other physiological measurements, making it an important factor in the management of critically ill patients, but no clinical studies have investigated the reproducibility of intra-abdominal pressure (IAP) measurement to ensure diagnostic accuracy. This study evaluated the intraobserver and interobserver variability of bladder pressure measurements. DESIGN AND SETTING: Prospective, observational study in a university-based adult surgical intensive care unit. PATIENTS: Critically ill patients undergoing intra-abdominal pressure readings, measured by nursing staff. MEASUREMENTS AND RESULTS: The study compared patient IAP measurements obtained by the same nurse (intraobserver variation) and between two different nurses (interobserver variation) in critical care patients with clinical indications for IAP monitoring. Data related to the nursing technique and performance were observed and collected for each IAP measurement obtained. Good correlation of bladder pressure measurements between the same and different individuals was found. Intraobserver and interobserver Pearson's correlations for measured IAP were 0.934 and 0.950, respectively. A unit protocol for IAP measurement standardization was modified based on observational data collected. CONCLUSIONS: Intra-abdominal pressure can be accurately and reliably measured in critically ill patients by utilizing a standardized measurement device combined with a standardized clinical protocol.

Survey of intensive care physicians on the recognition and management of intra-abdominal hypertension and abdominal compartment syndrome.

OBJECTIVE: To assess current understanding and clinical management of intra-abdominal hypertension and abdominal compartment syndrome among critical care physicians. DESIGN: A ten-question, written survey. SETTING: University health sciences center. SUBJECTS: Physician members of the Society of Critical Care Medicine (SCCM). INTERVENTIONS: The survey was sent to 4,538 SCCM members with a response rate of 35.7% (1622). MEASUREMENTS AND MAIN RESULTS: Primary training, intensive care unit type, and methods for management of abdominal compartment syndrome were assessed. Surgically trained intensivists managed the highest number of abdominal compartment syndrome cases (47% managed 4-10 cases, 16% managed >10 cases). No cases were seen by 25% of medically trained and pediatric trained intensivists. Respondents agreed that bladder pressures and clinical variables were needed to diagnose abdominal compartment syndrome (70%) vs. bladder pressure (7%) or clinical variables (20%) alone. Two percent of surgical intensivists were unaware of a bladder pressure measurement procedure compared with 24% (p < .0001) of pediatric and 23% (p < .0001) of medical intensivists. Forty-two percent of respondents believed bladder pressures of 20-27 mm Hg may cause physiologic compromise. However, 25-27% of pediatric, medicine, or anesthesia trained intensivists believed that compromise occurs between 12 and 19 mm Hg compared with 18% of surgeons. No respondent believed that physiologic compromise occurred at <8 mm Hg. Thirty-eight percent of pediatric intensivists believed that physiologic compromise was patient dependent vs. 7-17% from other specialties (p < .0001; all comparisons). In managing intra-abdominal hypertension, 33% of pediatric intensivists and 19.6% of medical intensivists would never use decompression laparotomy to treat abdominal compartment syndrome compared with 3.6% of intensivists with surgical training (p < .0001; both comparisons). CONCLUSIONS: Significant variation across medical training exists in the management of intra-abdominal hypertension and abdominal compartment syndrome. A significant percentage of intensivists may be unaware of current approaches to abdominal compartment syndrome management including monitoring bladder pressures and decompression laparotomy. Future research and education are necessary to establish clear diagnostic criteria and standards for treatment of this relatively common life-threatening disease process.

Evaluation of an electronic esophageal detector device in patients with morbid obesity and pulmonary failure.

OBJECTIVE: Undetected esophageal intubation can result in permanent injury or death. Clinical confirmation of tube location may be misleading. Adjunctive methods should be used to supplement clinical judgment. Unfortunately, end-tidal carbon dioxide may misidentify properly placed tracheal tubes in low perfusion situations, while esophageal detector devices (EDDs) may misidentify properly placed tracheal tubes in situations where little airway dead space exists (morbid obesity, pulmonary failure). This study evaluated a modified EDD (the electronic esophageal detector device, or EEDD) designed to eliminate the problem of misidentified tracheal intubations. METHODS: Intubated morbidly obese or pulmonary failure patients were eligible for study entry. All endotracheal tubes (ETTs) were confirmed to be tracheal by waveform capnography and clinical judgment prior to study entry. Following consent, all patients were attached to the EEDD and a "measurement" was made to determine the "location" of their ETTs. Probability of misidentifying a tracheal intubation in these high-risk populations was calculated using a log-normal distribution method. RESULTS: Twenty-seven morbidly obese patients and 37 pulmonary failure patients were entered. The EEDD correctly identified all tracheal intubations in these patients, giving a false-negative rate of zero. The probability of misidentifying a tracheal intubation in the combined group was 0.06%. CONCLUSION: This study demonstrates that the EEDD reliably identifies tracheal intubations in situations where standard EDDs may fail. However, future studies must determine the reliability of this device for identification of esophageal intubations and the reliability of this device in the less controlled emergency department and prehospital settings.