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.     

Energy measurements and requirements of critically ill patients

The energy expenditure of the critically ill patient is influenced by many factors, thus making it difficult to predict. Measurement of energy expenditure in mechanically ventilated patients receiving elevated oxygen concentrations requires a good understanding of the measurement technique and its limitations, whether it be the gas exchange or Fick method. More investigation is needed to better understand the determinants of energy expenditure, as well as the total energy requirements of the critically ill patient.     

危重病人胃残留量与误吸的相关性研究

[目的]研究危重病人误吸与胃残留量和其他相关因素的相关性。[方法]对206例鼻饲病人进行为期3d的测量研究,观察病人鼻饲和误吸情况,检测病人痰液样本中的胃蛋白酶、胃残留量,评估意识水平和急性生理和慢性健康评分,采用统计学方法分析胃残留量以及其他相关危险因素与误吸的关系。[结果]69．8％痰液样本胃蛋白酶测定为阳性,胃蛋白酶检测阳性率随胃残留量值增高逐渐增加,不同胃残留置与频繁误吸和少有误吸发生情况有关;Logistic回归模型分析发现胃残留量测定大于150mL、哥拉斯格昏迷评分〈9分和病人靠背倾角％30。是误吸发生的危险因素。[结论]胃残留量、病人意识状态和病人靠背倾角是误吸发生的危险因素。     

危重病人胃残留量与误吸的相关性研究

[目的]研究危重病人误吸与胃残留量和其他相关因素的相关性。[方法]对206例鼻饲病人进行为期3d的测量研究,观察病人鼻饲和误吸情况,检测病人痰液样本中的胃蛋白酶、胃残留量,评估意识水平和急性生理和慢性健康评分,采用统计学方法分析胃残留量以及其他相关危险因素与误吸的关系。[结果]69.8%痰液样本胃蛋白酶测定为阳性,胃蛋白酶检测阳性率随胃残留量值增高逐渐增加,不同胃残留置与频繁误吸和少有误吸发生情况有关;Logistic回归模型分析发现胃残留量测定大于150mL、哥拉斯格昏迷评分<9分和病人靠背倾角<30°是误吸发生的危险因素。[结论]胃残留量、病人意识状态和病人靠背倾角是误吸发生的危险因素。     

Intra-abdominal pressure monitoring for critically ill patients

Increased intra-abdominal pressure (IAP) is associated with a variety of clinical situations and has profound effects, both locally and systemically, that may result in organ dysfunction and failure. If not identified and treated promptly, increased IAP can be fatal. Urinary bladder pressure monitoring is a simple and reliable method of quantifying IAP and is a key factor leading to prompt management and a successful outcome for patients.     

Relationship between central venous pressure and bioimpedance vector analysis in critically ill patients

OBJECTIVE: To assess the relationship between central venous pressure values and bioelectrical impedance vector analysis (BIVA), which may be used as complementary methods in the bedside monitoring of fluid status. DESIGN: Cross-sectional evaluation of a consecutive sample. SETTING: Intensive care unit of a university hospital. PATIENTS: One hundred and twenty-one consecutive Caucasian, adult patients of either gender, for whom routine central venous pressure measurements were available. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Central venous pressure values and impedance vector components (i.e., resistance and reactance) were determined simultaneously. Total body water predictions were obtained from regression equations according to either conventional bioimpedance analysis or anthropometry (Watson and Hume formulas). Variability of total body water predictions was unacceptable for clinical purposes. Central venous pressure values significantly and inversely correlated with individual impedance vector components (r2 = .28 and r2 = .27 with resistance and reactance, respectively), and with both vector components together (R2 = .31). Patients were classified in three groups according to their central venous pressure value: low (0 to 3 mm Hg); medium (4 to 12 mm Hg); and high (13 to 20 mm Hg). Three BIVA patterns were considered: vectors within the target (reference) 75% tolerance ellipse (normal tissue hydration); long vectors out of the upper pole of the target (dehydration); and short vectors out of the lower pole of the target (fluid overload). The agreement between BIVA and central venous pressure indications was good in the high central venous pressure group (93% short vectors), moderate in the medium central venous pressure group (35% normal vectors), and poor in low central venous pressure group (10% long vectors). CONCLUSIONS: Central venous pressure values correlated with direct impedance measurements more than with total body water predictions. Whereas central venous pressure values >12 mm Hg were associated with shorter impedance vectors in 93% of patients, indicating fluid overload, central venous pressure values <3 mm Hg were associated with long impedance vectors in only 10% of patients, indicating tissue dehydration. The combined evaluation of intensive care unit patients by BIVA and central venous pressure may be useful in therapy planning, particularly in those with low central venous pressure in whom reduced, preserved, or increased tissue fluid content can be detected by BIVA.     

Gentamicin volume of distribution in critically ill septic patients

Gentamicin intrapatient pharmacokinetics variations were studied in 40 critically ill medical patients, suffering gram-negative sepsis. These patients were studied in two phases throughout gentamicin treatment: firstly, on the second day of treatment, when aggressive fluid therapy was required, and secondly, five days later, when patients had achieved a more stable clinical condition. Pharmacokinetic parameters were determined using least squares linear regression analysis assuming a one-compartment model using the Sawchuk-Zaske method. The apparent volume of distribution (Vd) in the first phase of the study was 0.43±0.12 L/kg, while on the seventh day of treatment it was 0.29±0.17 L/kg (p<0.001). Statistically significant differences were also observed for peak serum concentration (p<0.001), total dosage recommended (p<0.001) and half-life (p<0.05), whilst differences were not found for trough levels. From the analysis of the results obtained, we recommend increasing the initial dosage and monitoring plasma levels within the first days of therapy in critically ill patients treated with gentamicin, since important variations in aminoglycoside Vd related to disease, fluid balance and renal function, commonly occur in these patients.     

Ultrasound assessment of gastric volume in critically ill patients

Purpose

To assess the feasibility and validity of ultrasonographic measurement of gastric antral cross-sectional area (usCSA) in critically ill patients to predict gastric volume and the use of computed tomography (CT) as a reference to measure gastric volume.

Method

This single-center, prospective, cross-sectional study included 55 critically ill patients who had an abdominal CT scan. usCSA measurements were performed within the hour preceding the CT scan. Gastric volumes were measured on the CT scan using semiautomatic software. The feasibility rate, performing conditions (% “good” and “poor”), internal and external validity of antral usCSA measurements, performed by an ICU physician, were assessed to predict gastric volume.

Results

Antral usCSA measurements were feasible in 95 % of cases and were positively correlated with gastric volume measured by the CT scan when performed in “good” conditions (65 %) (r = 0.43). There was good reproducibility of measurements (intraclass correlation coefficient of 0.97, CI 95 % 0.96–0.99) and there was clinically acceptable agreement between measurements performed by radiologists and intensivists (bias ?0.12 cm²). The receiver operating characteristic curve identified a cutoff value of 3.6 cm² that discriminated an “at-risk stomach” (volume >0.8 mL/kg) at a sensitivity of 76 % and a specificity of 78 %.

Conclusions

Ultrasonographic measurement of antral CSA is feasible and reliable in the majority of critically ill patients. This technique could be useful to manage critically ill patients at risk of aspiration or with enteral feeding.     

The clinical application of pulse contour cardiac output and intrathoracic volume measurements in critically ill patients.

Cardiac output (CO) determination by pulmonary artery (PA) catheter has increasingly been criticised within the literature due to its invasive nature and poor correlation between the pressure measurements and intravascular volume status in mechanically ventilated patients. Consequently, alternative less invasive technologies to PA catheterisation are emerging within intensive care. One such novel technology are pulse contour CO (PCCO) systems. They establish comprehensive and continuous haemodynamic monitoring utilising a central venous catheter (CVC) and an arterial line. Furthermore, a key feature of this technology is its ability to produce intrathoracic volume measurements which may provide a better estimation of cardiac preload as well as indicate the presence and severity of pulmonary oedema. This article aims to discuss the theoretical basis and clinical application of PCCO systems, how PCCO systems differ from PA catheters and how the intrathoracic volume measurements are derived. Understanding these advanced concepts will ensure that clinicians are able to employ this innovative monitoring technology more effectively.     

Association between out-of-hospital emergency department transfer and poor hospital outcome in critically ill stroke patients

Introduction

Transfer of critically ill patients from outside emergency department has the potential for delaying the admission to the intensive care unit. We sought to determine the effect of outside emergency department transfer on hospital outcomes in critically ill patients with stroke.

Methods

We designed a retrospective cohort analysis using a prospectively compiled and maintained registry (Cerner Project IMPACT). Patients with acute ischemic stroke and intracerebral hemorrhage admitted to our intensive care unit from our emergency department and transfers from outside emergency department within 24 hours of stroke between January 1, 2003, and December 31, 2008, were selected for the analysis. Data collected included demographics, admission physiologic variables, Glasgow Coma Scale, Acute Physiology and Chronic Health Evaluation II score, and total intensive care unit and hospital length of stay. Primary (poor) outcome was a composite of death or fully dependent status at hospital discharge, and secondary outcomes were intensive care unit and hospital length of stay. To assess for the impact of outside emergency department transfer on primary and secondary outcomes, demographic and admission clinical variables were used to construct logistic regression models using the outcome measure as a dependent variable.

Results

A total of 448 patients were selected for analysis. The mean age was 65 ± 14 years, of which 214 (48%) were male and 282 (65%) white, 152 (34%) were patients with acute ischemic stroke, and 296 (66%) were patients with intracerebral hemorrhage. The median hospital length of stay was 7 days (interquartile range, 4-11 days) and median intensive care unit length of stay was 2 days (interquartile range, 1-3 days). Overall hospital mortality was 30%, and outside emergency department transfer increased the odds of poor outcome by 2-fold (65% vs 34%; P = .05). Multivariate regression analysis showed that age (odds ratio [OR], 1.02; 95% confidence interval [CI], 1.01-1.1), Acute Physiology and Chronic Health Evaluation II score >14 (OR, 1.9; 95% CI, 1.3-2.7), Glasgow Coma Scale <12 (OR, 2.0; 95% CI, 1.4-2.8), do-not-resuscitate status (OR, 3.5; 95% CI, 2.2-5.9), and outside emergency department transfers (OR, 1.4; 95% CI, 1.02-1.8) were independently associated with poor outcome. Outside emergency department transfer was not significantly associated with secondary outcomes.

Conclusion

These data suggest that in critically ill patients with stroke, transfer from outside emergency department is independently associated with poor outcome at hospital discharge. Further research is needed as to identify the potential causes for this effect.     

Predictors and consequences of pneumonia in critically ill patients with stroke

OBJECTIVE: Ascertain the incidence, predictors and consequences of early (within 48 hours of admission) and nosocomial pneumonia among critically ill patients with stroke. METHODS: Medical records of critically ill patients with acute stroke were reviewed. Predictors and consequences of pneumonia were determined with analysis of variance. RESULTS: 55 patients, aged 33 to 91 (median 74) years, were admitted. The stroke was located at the brainstem in 14 (26.4%) patients. Nine patients (16.4%) had early pneumonia and additional 17 patients (30.9%) developed nosocomial pneumonia. Patients with brain-stem stroke were more likely to develop early pneumonia (p =.04). Nosocomial pneumonia incidence was higher in patients who failed swallowing evaluation (RR = 6.3, 95% CI: 0.9-43.0) and in those who were intubated (58.6% v 0%, p =.00008). Also, nosocomial pneumonia was associated with longer duration of mechanical ventilation and prolonged hospital stay. Nineteen patients (34.5%) died at the hospital. They were more likely to be older (median 77 versus 69 years, p =.03) with higher admission acuity of illness. CONCLUSION: Pneumonia complicated stroke in 47% of critically ill patients and adversely impacted the duration of mechanical ventilation and overall length of hospital stay. Aggressive preventive measures are needed to reduce pneumonia occurrence in stroke patients.     

Estimation of inspiratory muscle pressure in critically ill patients

Background  

Recently, a new technology has been introduced aiming to monitor and improve patient ventilator interaction (PVI monitor). With the PVI monitor, a signal representing an estimation of the patient’s total inspiratory muscle pressure (Pmus_PVI) is calculated from the equation of motion, utilizing estimated values of resistance and elastance of the respiratory system.     

Lactate measurements in critically ill patients with a hand-held analyser

Objective: To compare a recently introduced hand-held lactate analyser to a reference point of care analyser (POCI) and the hospital laboratory in a critical care setting. Setting: 10-bed surgical/medical intensive care unit in a teaching hospital. Patients and methods: In 39 critically ill patients, 50 convenience measurement cycles consisting of three paired measurements at 30-min intervals were carried out with a hand-held analyser, reference POCI and hospital laboratory using arterial blood samples. Duplicate measurements with the hand-held analyser were done in 129 blood samples. Results: Lactate levels ranged from 1.1 to 21.0 mmol/l. Regression analysis of the hand-held analyser and laboratory showed a slope of 1.01, bias of –0.38 mmol/l, R ² = 0.97 and mean error of 14.9 %. Reference POCI versus laboratory: slope = 1.07, bias = –0.29 mmol/l, R ² = 0.98 and mean error of 6.4 %. Hand-held analyser versus reference POCI: slope = 0.90, bias = 0.09 mmol/l and R ² = 0.92. The hand-held analyser showed acceptable precision. Conclusion: The hand-held lactate analyser can reliably measure arterial blood lactate levels in critically ill patients. Received: 19 January 1999 Accepted: 18 June 1999     

Relation of echocardiographic preload indices to stroke volume in critically ill patients with normal and low cardiac index

Objective: To examine the usefulness of preload indices obtained by transoesophageal echocardiography (TOE) for estimating stroke volume at various levels of cardiac index. Design: Prospective clinical study. Setting: Intensive care unit with surgical patients. Patients: 16 ventilated patients monitored via Swan-Ganz catheterization and TOE. Interventions: Echocardiographic images of left ventricular cross-sectional short-axis areas were analysed for the preload indices end-diastolic area (EDA), stroke area and end-diastolic wall stress. The relation between these indices and stroke volume, calculated from thermodilution cardiac output, was analysed in all patients and in nine patient groups discriminated by various ranges in heart rate (≤ 70 to > 110 beats/min), pulmonary artery occlusion pressure (≤ 8 to > 12 mm Hg) and cardiac index (≤ 3.0 to > 4.2 l/min per m²). Measurements and results: Overall stroke volume (n = 155) correlated significantly (p < 0.0001) with EDA (r = 0.89) and stroke area (r = 0.80). The correlation with end-diastolic wall stress was non-significant (r = 0.51). Linearity in the relation between stroke volume and EDA or stroke area was independent of variations in heart rate and pulmonary artery occlusion pressure. Stroke volume correlated well with EDA and stroke area, when cardiac index was normal or high, but the relation slightly deteriorated (r = 0.63 to ≤ 0.72) when the cardiac index was low. Changes in EDA and stroke area by more than 1, 2 or 3 cm² were weak predictors for changes in stroke volume greater than 20 %. Conclusions: Stability of the relation between echocardiographic preload indices and stroke volume emphasize the potential of TOE for continuous preload monitoring in the critically ill. Received: 11 April 1996 Accepted: 2 January 1997     

Cardiac output measurements using the bioreactance technique in critically ill patients

Measurement of cardiac output (CO) using minimally invasive devices has gained popularity. In 11 patients we compared CO values obtained using the bioreactance technique - a new continuous, totally non-invasive CO monitor - with those obtained by semi-continuous thermodilution using a pulmonary artery catheter. We obtained CO measurements at study inclusion and after any relevant change in hemodynamic status (spontaneous or during fluid challenge, inotrope or vasopressor infusions). There was a poor correlation between the two techniques (r = 0.145). These data suggest that caution should be applied when using bioreactance devices in critically ill patients.Measurement of cardiac output (CO) requires use of invasive or minimally invasive devices; the use of noninvasive and minimally invasive devices has gained popularity in recent years. The bioreactance technique is a relatively new, continuous, totally non-invasive technique for measuring CO that is easily implemented. This new technique involves analyzing phase shifts of a delivered oscillating current that occur when the current traverses the thoracic cavity [1], and differs from traditional bioimpedance techniques that rely on analysis of changes in signal amplitude. Most validation studies in critically ill patients have shown good correlation and/or agreement of bioreactance values compared with CO values obtained using other devices in patients admitted after cardiac surgery [2-4]. However, validation in critically ill patients is lacking.As part of the internal evaluation of a bioreactance device before its implementation in the unit (evaluation of new non-invasive monitoring systems before introduction in the unit does not require the approval of the ethics committee in our institution), we compared CO values obtained using the bioreactance technique (NICOM system; Cheetah Medical Inc., Portland, OR, USA) with those measured using semi-continuous cardiac output by thermodilution (CCO) with a pulmonary artery catheter (Vigilance, Edwards LifeSciences, Irvine, CA, USA). In 11 patients the CO values were compared at study inclusion and each time a relevant change in hemodynamics and/or in therapeutics (for example, fluid challenge, inotrope or vasopressor infusions) was observed (Table ​(Table11).

Table 1

Patient characteristics

Accuracy of bedside capillary blood glucose measurements in critically ill patients

OBJECTIVE: To compare the accuracy of fingerstick with laboratory venous plasma glucose measurements (laboratory glucose) in medical ICU patients and to determine the factors which interfere with the accuracy of fingerstick measurements. PARTICIPANTS: The study included 80 consecutive patients aged 58+/-7 years, BMI 29.5+/-9.0, and APACHE II score 15+/-6 (277 simultaneous paired measurements). MEASUREMENTS: This prospective observational study compared fingerstick measurements to simultaneously sampled laboratory glucose once a day in patients in our medical ICU (twice daily if on an insulin infusion). Data recorded included patient demographics, admission diagnoses, APACHE II score, BMI, daily hematocrit, arterial blood gasses, chemistry results, concomitant medications (including vasopressors and corticosteroids), and upper extremity edema. Accuracy was defined as the percentage of paired values not in accord (>15 mg dl(-1)/ 0.83 mmol(-1)l(-1) difference for laboratory values <75 mg dl(-1)/4.12 mmol(-1)l(-1) and >20% difference for laboratory values >or=75 mg/dl). Outliers (blood glucose difference >100 mg dl(-1)/5.56 mmol(-1) l(-1)) were excluded from the correlation and distribution analyses. RESULTS: Mean fingerstick glucose was 129+/-45 mg/dl (7.2+/-2.5 mmol/l) and mean laboratory glucose 123+/-44 mg/dl (6.8+/-2.4 mmol/l). The correlation coefficient between the two values was 0.9110 (Clinical and Laboratory Standards Institute threshold 0.9751). The mean difference (bias) between the two methods was 8.6+/-18.6 mg/dl (0.48+/-1.0 mmol/l) and limits of agreement +45.8 and -28.6 mg/dl (+2.5 and -1.6 mmol/l). Fifty-three (19%) paired measurements in 22 patients were not in accord (CLSI threshold 相似文献