Critical Care Literature Review

Noninvasive Hemodynamic Monitoring

 

1: Pediatr Res. 2008 Jun;63(6):691-6.
Feasibility of noninvasive continuous finger arterial blood pressure measurements in very young children, aged 0-4 years.
Andriessen P, Schraa O, van Den Bosch-Ruis W, Jan Ten Harkel D, Settels JJ,
Oetomo SB, Blanco CE. Neonatal Intensive Care Unit, Máxima Medical Center, 5500 MB Veldhoven, The Netherlands. p.andriessen@mmc.nl

Our goal was to study the feasibility of continuous noninvasive finger blood pressure (BP) monitoring in very young children, aged 0-4 y. To achieve this, we designed a set of small-sized finger cuffs based on the assessment of finger circumference. Finger arterial BP measured by a volume clamp device (Finapres technology) was compared with simultaneously measured intra-arterial BP in 15 very young children (median age, 5 mo; range, 0-48), admitted to the intensive care unit for vital monitoring. The finger cuff-derived BP waveforms showed good resemblance with the invasive arterial waveforms (mean root-mean-square error, 3 mm Hg). The correlation coefficient between both methods was 0.79 +/- 0.19 systolic and 0.74 +/- 0.24 diastolic. The correlation coefficient of beat-to-beat changes between both methods was 0.82 +/- 0.18 and 0.75 +/- 0.21, respectively. Three measurements were related to measurement errors (loose cuff application; wrong set-point). Excluding these erroneous measurements resulted in clinically acceptable measurement bias (-3.8 mm Hg) and 95% limits of agreement (-10.4 to + 2.8 mm Hg) of mean BP values. We conclude that continuous finger BP measurement is feasible in very young children. However, cuff application is critical, and the current set-point algorithm needs to be revised in very young children.

2: Curr Opin Crit Care. 2008 Jun;14(3):317-21.
Noninvasive assessment of arterial pressure.
Chemla D, Teboul JL, Richard C. Research Team EA4046, Paris-Sud University, France. denis.chemla@bct.aphp.fr

PURPOSE OF REVIEW: To briefly review recent advances in the noninvasive assessment of arterial pressure (indirect methods) in the field of critical care. RECENT FINDINGS: Automated oscillometric measurements underestimate intraarterial systolic blood pressure. Digital photoplethysmography has led to conflicting results, although the obtained respiratory pulse pressure variation correlates with the fluid-challenge-induced changes in stroke volume. The pulse oximetry photoplethysmographic signal recorded at the digital or ear level may be useful in monitoring respiratory arterial pressure variations, although technical improvements and clarifications are needed. Arterial tonometry is increasingly used in the cardiovascular field to reconstruct central aortic pressure. A recent study has shown that radial artery tonometry is feasible in hemodynamically stable patients and that peripheral pulse pressure reflects the combined influences of arterial stiffness and stroke volume, especially in elderly patients. The limitations of this technique include the potential bias related to the use of a generalized transfer function and the difficulty in obtaining reliable recordings in hemodynamically unstable patients. SUMMARY: Intraarterial blood pressure must be preferred over noninvasive blood pressure recordings when critical decisions are required. In hemodynamically stable patients, valuable information may be obtained by using noninvasive techniques, amongst which arterial tonometry seems especially promising.

3: Pediatr Crit Care Med. 2008 May;9(3):310-2.
Comment in: Pediatr Crit Care Med. 2008 May;9(3):333-4.
Assessment of cardiac output in children: a comparison between the pressure recording analytical method and Doppler echocardiography.
Calamandrei M, Mirabile L, Muschetta S, Gensini GF, De Simone L, Romano SM. Department of Anaesthesia and Intensive Care, Meyer Children's Hospital, Florence, Italy. m.calamandrei@meyer.it

OBJECTIVE: To assess cardiac output in pediatric patients with the pressure recording analytical method (PRAM) and the Doppler echocardiography method. PRAM derives cardiac output from beat-by-beat analysis of the arterial pressure profile (systolic and diastolic phase) in the time domain. DESIGN: A prospective observational study. SETTING: Pediatric intensive care unit at a tertiary care children's hospital. PATIENTS: Forty-eight patients between the ages of 1 month and 18 yrs. INTERVENTIONS: Femoral or radial artery catheterization and mechanical ventilation. MEASUREMENTS AND MAIN RESULTS: Cardiac output was simultaneously estimated by Doppler echocardiography and PRAM. Cardiac output values obtained by Doppler echocardiography (2.7 +/- 1.6 L/min, range 0.92-8.20) were significantly correlated with those estimated by PRAM (2.6 +/- 1.7 L/min, range 0.89-7.48; r2 = .99, p < .01). The mean difference between the two estimates was 0.12 +/- 0.27 L x min(-1) (95% confidence interval, -0.54 to 0.77 L x min(-1)). CONCLUSIONS: In the range of ages evaluated, PRAM provides reliable estimates of cardiac output when compared with noninvasive techniques.

4: J Trauma. 2008 Apr;64(4 Suppl):S333-41.
Closed-loop control of fluid therapy for treatment of hypovolemia.
Kramer GC, Kinsky MP, Prough DS, Salinas J, Sondeen JL, Hazel-Scerbo ML, Mitchell CE. Department of Anesthesiology, Resuscitation Research Laboratory, University of Texas Medical Branch, Galveston, TX 77555-0591, USA. gkramer@utmb.edu

Closed-loop algorithms and resuscitation systems are being developed to control IV infusion rate during early resuscitation of hypovolemia. Although several different physiologic variables have been suggested as an endpoint to guide fluid therapy, blood pressure remains the most used variable for the initial assessment of hemorrhagic shock and the treatment response to volume loading. Closed-loop algorithms use a controller function to alter infusion rate inversely to blood pressure. Studies in hemorrhaged conscious sheep suggest that: (1) a small reduction in target blood pressure can result in a significant reduction in volume requirement; (2) nonlinear algorithms may reduce the risk of increased internal bleeding during resuscitation; (3) algorithm control functions based on proportional-integral, fuzzy logic, or nonlinear decision tables were found to restore and maintain blood pressure equally well. Proportional-integral and fuzzy logic algorithms reduced mean fluid volume requirements compared with the nonlinear decision table; and (4) several algorithms have been constructed to the specific mechanism of injury and the volume expansion properties of different fluids. Closed-loop systems are undergoing translation from animal to patient studies. Future smart resuscitation systems will benefit from new noninvasive technologies for monitoring blood pressure and the development of computer controlled high flow intravenous pumps.

5: J Physiol Pharmacol. 2007 Nov;58 Suppl 5(Pt 2):591-602.
Diagnostics in pulmonary hypertension.
Schannwell CM, Steiner S, Strauer BE. University Hospital Düsseldorf, Clinic of Cardiology, Pneumology, and Angiology Düsseldorf, Germany.

Pulmonary hypertension is a serious disease with a poor prognosis. Pulmonary hypertension is defined by a mean pulmonary arterial pressure over 25 mm Hg at rest or over 30 mm Hg during activity. According to the recent WHO classification from 2003 pulmonary hypertension can be categorized as pulmonary arterial hypertension, pulmonary venous hypertension, hypoxic pulmonary hypertension, chronic thromboembolic pulmonary hypertension and pulmonary hypertension from other causes. Pulmonary arterial hypertension is characterized histopathologically by vasoconstriction, vascular proliferation, in situ thrombosis, and remodeling of all 3 levels of the vascular walls. These pathologic changes result in progressive increases in the mean pulmonary artery pressure and pulmonary vascular resistance, which, if untreated leads to right-ventricular failure and death. Early in the disease process, the signs and symptoms of PAH are often nonspecific, making diagnosis challenging. Patients often present with progressively worsening dyspnea and fatigue. Patients with severe pulmonary arterial hypertension die of right heart failure. The diagnostic procedures include clinical history and physical examination, a standard chest radiography, electrocardiography, transthoracic Doppler echocardiography, pulmonary function tests, arterial blood gas analysis, ventilation and perfusion lung scan, high-resolution computed tomography of the lungs, contrast-enhanced spiral computed tomography of the lungs and pulmonary angiography, blood tests and immunology, abdominal ultrasound scan, exercise capacity assessment, and hemodynamic evaluation. Invasive and non-invasive markers of disease severity, either biomarkers or physiological parameter and tests that can be widely applied, have been proposed to reliably monitor the clinical course. Pulmonary biopsy is rarely indicated. Transthoracic echocardiography is a key screening tool in the diagnostic algorithm. Because transthoracic echocardiography is an inexpensive, easy, and reproducible method, it is the most commonly used noninvasive diagnostic tool to determine pulmonary arterial pressure. But it not only provides an estimate of pulmonary pressure at rest and during exercise, but it may also help to exclude any secondary causes of pulmonary hypertension, predict the prognosis, monitor the efficacy of specific therapeutic interventions, and detect the preclinical stage of the disease. In addition, the measurement of serum markers, such as brain natriuretic peptide (BNP), are diagnostically useful and of prognostic significance. Once the diagnosis and etiology of pulmonary hypertension have been established, several parameters can predict outcome in these patients: functional class, right ventricular function, pulmonary hemodynamics, and certain laboratory parameters. Also, exercise parameters such as walking distance, peak oxygen uptake or peak systolic blood pressure can reliably predict prognosis in these patients.

6: Anesth Analg. 2008 Apr;106(4):1189-94, table of contents.
Comment in: Anesth Analg. 2008 Apr;106(4):1031-3.
Does the Pleth variability index indicate the respiratory-induced variation in the plethysmogram and arterial pressure waveforms?
Cannesson M, Delannoy B, Morand A, Rosamel P, Attof Y, Bastien O, Lehot JJ. Hospices Civils de Lyon, Department of Anesthesiology and Intensive Care, Louis Pradel Hospital and Claude Bernard Lyon 1 University, INSERM ERI 22, Lyon, France. maxime_cannesson@hotmail.com

BACKGROUND: Respiratory variations in the pulse oximeter plethysmographic waveform amplitude (deltaPOP) are sensitive to changes in preload and can predict fluid responsiveness in mechanically ventilated patients. However, they cannot be easily calculated from a bedside monitor. Pleth variability index (PVI, Masimo Corp., Irvine, CA) is a new algorithm that automatically calculates deltaPOP. The aim of our study was to test the ability of this new device to automatically and continuously monitor deltaPOP. METHODS: Twenty-five patients were studied after induction of general anesthesia. PVI automatically and continuously calculates the respiratory variations in the plethysmography waveform amplitude (perfusion index). Data (mean arterial blood pressure, central venous pressure, respiratory variations in arterial pulse pressure, deltaPOP, and PVI) were recorded at baseline in anti-Trendelenburg position and, finally, in Trendelenburg position. RESULTS: There was a significant relationship between PVI and deltaPOP (r = 0.92; P < 0.05). Over the 75 measurements, 42 (56%) presented a deltaPOP value > 13%. A PVI threshold value of 11.5% was able to discriminate between deltaPOP >13% and deltaPOP < or = 13% with a sensitivity of 93% and a specificity of 97%. Area under the curve for PVI to predict deltaPOP > 13% was 0.990 +/- 0.07. CONCLUSION: This study is the first to demonstrate the ability of PVI, an index automatically derived from the pulse oximeter waveform analysis, to automatically and continuously monitor deltaPOP. This new index has potential clinical applications for noninvasive fluid responsiveness monitoring.

7: Crit Care Med. 2008 Jan;36(1 Suppl):S40-3.
Hemodynamic monitoring in acute heart failure.
Cotter G, Cotter OM, Kaluski E. Department of Cardiology, Duke University Medical Center, Durham, NC, USA. gad.cotter@duke.edu

Hemodynamic monitoring has moved in the last few years from being the holy grail of evaluating patients with acute heart failure to being all but extinct. Recent studies have not demonstrated any sustained benefits from right heart catheterization, and some studies have even suggested harm due to adverse events related to this invasive procedure. It is possible that this lack of efficacy is related to multiple inherent deficiencies in the design of these studies, including the inclusion of patients with chronic heart failure or mild acute heart failure, use of the reduction in pulmonary artery occlusion pressure as the main hemodynamic target for intervention, choice of treatment algorithms, and selection of ambitious long-term efficacy and safety end points. This review discusses the role of hemodynamic monitoring in patients with acute heart failure. We suggest that right heart catheterization should be reserved for patients with acute heart failure and impending respiratory or circulatory failure especially in the presence of a diagnostic or therapeutic dilemma or when encountering acute heart failure or hemodynamic lability refractory to conventional therapy. Therapeutic algorithms emphasizing modern variables for cardiovascular performance and using safer and more efficacious individualized therapies and possibly noninvasive measurement of certain hemodynamic variables may enhance the likelihood of a beneficial effect for hemodynamic guided therapy.

8: Semin Cardiothorac Vasc Anesth. 2007 Dec;11(4):274-81.
A proposed algorithm for the intraoperative use of cerebral near-infrared spectroscopy.
Denault A, Deschamps A, Murkin JM. Department of Anesthesiology, Montreal Heart Institute, Montreal, Quebec, Canada. denault@videotron.ca

Near-infrared spectroscopy (NIRS) is a technique that can be used as a noninvasive and continuous monitor of the balance between cerebral oxygen delivery and consumption. The authors develop and propose an algorithm for the use of NIRS based on optimizing factors that can affect cerebral oxygen supply/demand. These factors are the position of the vascular cannula, perfusion pressure, arterial oxygen content, partial pressure of carbon dioxide, haemoglobin, cardiac output, and the cerebral metabolic rate of oxygen. Dissemination of a useful treatment algorithm is the primary purpose of this article. Further multicenter studies are necessary to confirm the benefits and cost-effectiveness of this promising monitoring modality.

9: J Vasc Surg. 2008 Feb;47(2):318-23.
Clinical reliability and utility of skin perfusion pressure measurement in ischemic limbs--comparison with other noninvasive diagnostic methods.
Yamada T, Ohta T, Ishibashi H, Sugimoto I, Iwata H, Takahashi M, Kawanishi J. Dpartment of Vascular Surgery, Aichi Medical University, Aichi-gun, Aichi, Japan. ohta1221@aichi-med-u.ac.jp <ohta1221@aichi-med-u.ac.jp>

PURPOSE: We studied whether the measurement of skin perfusion pressure (SPP) is useful for evaluating ischemic limbs and predicting wound healing. METHODS: Two hundred eleven patients (age range, 45 to 90 years; mean age, 69.6 +/- 9.2 years; 170 men and 41 women), 403 limbs with arteriosclerosis obliterans, were included in this study. Half of the patients had diabetes or were receiving dialysis or both. RESULTS: Significant correlations were found between SPP and ankle blood pressure (ABP), SPP and toe blood pressure (TBP), and SPP and the transcutaneous oxygen pressure (tcPO2) (P < .0001, r = 0.75; P < .0001, r = 0.85; P < .0001, r = 0.62; respectively). In 94 limbs with ulcer or gangrene, wound healing was predicted by the SPP. The mean SPP (mean +/- SD) in the healed-wound group (25 limbs, 48 +/- 20 mm Hg) was greater than that in the unhealed-wound group (69 limbs, 23 +/- 11 mm Hg) (P <.001). According to the receiver operating characteristic (ROC) curve, the cut-off value of SPP was 40 mm Hg (sensitivity, 72%; specificity, 88%). Furthermore, we studied whether the combination of SPP and another measurement could predict wound healing more accurately than could any single variable. There was a strong correlation between SPP, TBP, and the healing rate (P < .001, r = 0.69) and healing could be accurately predicted if the SPP was greater than 40 mm Hg and if the TBP was greater than 30 mm Hg. CONCLUSIONS: Our results suggest that measurement of SPP is an objective method for assessing the severity of peripheral arterial disease or for predicting wound healing.

10: Clin Cardiol. 2007 Dec;30(12):615-20.
Development and validation of a noninvasive method to estimate cardiac output using cuff sphygmomanometry.
Chio SS, Tsai JJ, Hsu YM, Lapointe JC, Huynh-Covey T, Kwan OL, DeMaria AN. Pulse Metric, Inc.

BACKGROUND: Obtaining cardiac output (CO) measurements noninvasively during routine blood pressure recording can improve hypertension management. A new method has been developed that estimates cardiac output using pulse-waveform analysis (PWA) from a brachial cuff sphygmomanometer. This study evaluates the ability of PWA to track changes in CO as derived by Doppler ultrasound during dobutamine stimulation. HYPOTHESIS: This study aims to validate the PWA CO estimation over a wide CO range as would be obtained by dobutamine stimulation during Doppler ultrasound evaluation. METHOD: A total of 48 patients undergoing standard dobutamine stress echocardiography testing for accepted clinical indications were enrolled. Among them, 44 patients (age 36-83, 18 females, 26 males) with good waveform data for analyses provided estimates of CO in this study. Noninvasive measurements of CO were performed using both Doppler ultrasound recordings and PWA techniques simultaneously at each stage of dobutamine infusion. RESULTS: A total of 207 simultaneous pulse-waveform analyses and Doppler measurements were taken during dobutamine stress on 44 cardiac patients. Linear regression analysis revealed good intra-patient correlation between pulse-waveform analysis and Doppler at different dobutamine-induced CO with coefficients from r = 0.69 to 0.98 (p < 0.05). Analysis of all patients yielded an overall correlation of r = 0.82 (p < 0.001, bias = 0.4 L/min, standard deviation = 1.8 L/min). CONCLUSION: The CO measured noninvasively from a sphygmomanometer using this PWA method correlates well with those of Doppler through a range of dobutamine-stimulated levels. The CO by PWA should be useful for monitoring hemodynamic changes in hypertensive and cardiac patients during routine blood pressure measurement.

11: Am Surg. 2007 Oct;73(10):1017-22.
The correlation of near-infrared spectroscopy with changes in oxygen delivery in a controlled model of altered perfusion.
Putnam B, Bricker S, Fedorka P, Zelada J, Shebrain S, Omari B, Bongard F. Department of Surgery, Los Angeles Biomedical Research Institute, Los Angeles County Harbor-UCLA Medical Center, Torrance, California 90509, USA. brantputnam@hotmail.com

Alterations in regional tissue perfusion may precede global indications of shock. This study compared regional tissue oxygenation saturation (StO2) using near-infrared spectroscopy with standard hemodynamic and biochemical variables in 40 patients undergoing cardiopulmonary bypass (CPB). Mean arterial pressure, cardiac output, oxygen delivery, arterial blood gases, and lactate were recorded at specific intervals during surgery. Data were organized by stage of procedure, and the relationship of StO2 to established parameters was investigated. With initiation of CPB, StO2 declined by 12.9 per cent (standard deviation +/- 14.75%) with a delayed increase in lactate from 0.9 (interquartile range [IQR], 0.6-1.5) mmol/L to 2.3 (IQR, 1.8-2.5) mmol/L. The minimum StO2 value preceded the maximum lactate level by an average time of 93.9 (standard deviation +/- 86.3) minutes. Additionally, a decrease in StO2 corresponded with an increase in base deficit of 4.84 (standard deviation +/- 2.37) mEq/L over the same period. Calculated oxygen delivery decreased from a baseline value of 754 (IQR, 560-950) mL/min to 472 (IQR, 396-600) mL/min with initiation and maintenance of CPB. For patients undergoing CPB, StO2 is a reliable, noninvasive monitor of perfusion, which correlates well with oxygen delivery and identifies perfusion deficits earlier than lactate or base deficit.

12: J Clin Monit Comput. 2007 Dec;21(6):345-51. Epub 2007 Oct 9.
Multi-channel electrical bioimpedance: a new noninvasive method to simultaneously measure cardiac and peripheral blood flow.
Stanley AW Jr, Herald JW, Athanasuleas CL, Jacob SC, Sims SW, Bartolucci AA, Tsoglin AN. Kemp-Carraway Heart Institute, Birmingham, AL, USA.

OBJECTIVES: We sought to assess the ability of a new multi-channel electrical bioimpedance (MEB) methodology to accurately measure both cardiac blood flow and peripheral limb blood flow. BACKGROUND: Cardiac output is the primary determinant of peripheral blood flow; however, optimal regional tissue perfusion is ultimately dependent on the patency of the arterial conduits that transport that flow. A complete understanding of regional tissue perfusion requires knowledge of both cardiac and peripheral blood flow. Existing noninvasive devices do not simultaneously assess the cardiac and peripheral circulations. METHODS: Cardiac blood flow (cardiac output) was measured by MEB in 30 healthy volunteers and was compared to a 2D-Echo Doppler cardiac output. Peripheral blood flow (regional ankle and arm flow) was measured by MEB in 15 healthy volunteers. The MEB ankle/arm flow ratio (AAI index) was then compared to a conventional ankle/brachial pressure ratio (ABI index). RESULTS: There was good correlation between the mean cardiac index by MEB (3.08 l/min/m2) and by Echo Doppler (3.13 l/min/m2) and bias and precision was 0.051 (1.6%) and +/-0.52 l/min/m2 (+/-17%), respectively. The close correlation was maintained for each measurement over a wide range of cardiac indices. There was good correlation between AAI and ABI measurements (p < 0.05) with a sensitivity of 100% and specificity of 100%. CONCLUSIONS: MEB methodology can precisely measure cardiac output and peripheral limb flow in healthy volunteers.

13: J Cardiothorac Vasc Anesth. 2007 Aug;21(4):535-9. Epub 2006 Dec 22.
Cerebral near-infrared spectroscopy in adult patients after cardiac surgery is not useful for monitoring absolute values but may reflect trends in venous oxygenation under clinical conditions.
Dullenkopf A, Baulig W, Weiss M, Schmid ER. Division of Cardiac Anesthesia, Institute of Anesthesiology, University Hospital, Zurich, Switzerland. alexander.dullenkopf@spital-limmattal.ch

OBJECTIVE: Cerebral near-infrared spectroscopy (NIRS) was evaluated for use in monitoring global oxygenation in adult patients after cardiac surgery. DESIGN: Prospective, randomized clinical monitoring study. SETTING: Intensive care unit for cardiac surgery; university hospital. PARTICIPANTS: The study included 35 patients scheduled for cardiac surgery with insertion of a pulmonary artery catheter; patients with known cerebral-vascular perfusion disturbances were excluded. INTERVENTIONS: Noninvasive cerebral NIRS oxygen saturation (rSO(2)) and conventional intensive care monitoring parameters were assessed. MEASUREMENTS AND MAIN RESULTS: Simple regression analysis was used to assess the correlation of rSO(2) to hemodynamic parameters. There was fair-to-moderate intersubject correlation to hemoglobin concentration (r = 0.45, p < 0.0001) and mixed venous oxygen saturation (SmvO(2)) (r = 0.33, p < 0.0001). Sensitivity and specificity of rSO(2) to detect substantial (>or=1 standard deviation) changes in mixed venous oxygen saturation were 94% and 81%, respectively. CONCLUSIONS: Cerebral NIRS in adult patients might not be the tool to replace mixed venous oxygen monitoring. Further work has to be done to assess its potential to reflect intraindividual trends.

14: Chest. 2007 Sep;132(3):786-92. Epub 2007 Jul 23.
Central venous blood oxygen saturation monitoring in patients with chronic pulmonary arterial hypertension treated with continuous IV epoprostenol: correlation with measurements of hemodynamics and plasma brain natriuretic peptide levels.
Chin KM, Channick RN, Kim NH, Rubin LJ. Department of Internal Medicine, University of Texas Southwestern Pulmonary Hypertension Program, 5909 Harry Hines Blvd, Dallas, TX 75235-9254, USA. kelly.chin@utsouthwestern.edu

BACKGROUND: IV epoprostenol is a highly effective therapy for pulmonary arterial hypertension (PAH). However, monitoring the efficacy and adjusting the dose of epoprostenol often requires serial invasive hemodynamic measurements. This study investigated whether superior vena cava (SVC) oxygen saturation measured from the indwelling catheter and brain natriuretic peptide (BNP) level would predict right heart catheterization markers associated with lower survival rates (right atrial pressure [RAP], > 10 mm Hg; pulmonary artery [PA] oxygen saturation, < 62%) in epoprostenol-treated patients with PAH. METHODS: Twenty-seven epoprostenol-treated PAH patients had a BNP level and SVC oxygen saturation measured from their indwelling central venous catheters. The results were compared with cardiac catheterization results. RESULTS: SVC oxygen saturation and BNP level both showed significant correlation with hemodynamic variables. BNP level correlated best with RAP (r = 0.66; p < 0.001), while SVC oxygen saturation correlated most closely with PA oxygen saturation (r = 0.91; p < 0.001). All patients with a BNP level of >or= 117 pg/mL had an elevated RAP (specificity, 100% [defined as a RAP of > 10 mm Hg]), but sensitivity was only 65%. An SVC oxygen saturation of < 64% showed a sensitivity of 89% and a specificity of 78% in predicting a PA oxygen saturation of < 62%. CONCLUSIONS: SVC oxygen saturation and BNP level predict hemodynamics associated with lower survival rates and may be useful as "noninvasive" markers of prognosis in epoprostenol-treated PAH patients. BNP levels have a lower sensitivity relative to specificity, and a normal BNP level did not exclude a high RAP or low PA oxygen saturation.

15. Anaesthesia. 2002 Sep;57(9):845-9.

Randomised controlled trial investigating the influence of intravenous fluid titration using oesophageal Doppler monitoring during bowel surgery.
Conway DH, Mayall R, Abdul-Latif MS, Gilligan S, Tackaberry C.

Abstract

Oesophageal Doppler monitoring allows non-invasive estimation of stroke volume and cardiac output. We studied the impact of Doppler guided fluid optimisation on haemodynamic parameters, peri-operative morbidity and hospital stay in patients undergoing major bowel surgery. Fifty-seven patients were randomly assigned to Doppler (D) or control (C) groups. All patients received intra-operative fluid therapy at the discretion of the non-investigating anaesthetist. In addition, Group D were given fluid challenges (3 ml x kg(-1)) guided by oesophageal Doppler. Group D received significantly more intra-operative colloid than Group C (mean 28 (SD 16) vs. 19.4 (SD 14.7) ml x kg(-1), p = 0.02). Cardiac output increased significantly for Group D whilst that of controls remained unchanged. The mean difference between the groups in final cardiac output was 0.87 l x min(-1) (95% confidence interval 0.31-1.43 l x min(-1), p = 0.003). Five control patients required postoperative critical care admission. Fluid titration using oesophageal Doppler during bowel surgery can improve haemodynamic parameters and may reduce critical care admissions postoperatively.


Your feedback is important to us. Please Contact Us to let us know how to make this site better. Thank you.