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Biomedical subjects

Karim Bendjelid

Publications and source records attributed to Karim Bendjelid.

At least 19 recordsLinked to original sources
PubMed2006

Increased intra-abdominal pressure affects respiratory variations in arterial pressure in normovolaemic and hypovolaemic mechanically ventilated healthy pigs.

OBJECTIVE: To evaluate the effect of increased intra-abdominal pressure (IAP) on the systolic and pulse pressure variations induced by positive pressure ventilation in a porcine model. DESIGN AND SETTING: Experimental study in a research laboratory. SUBJECTS: Seven mechanically ventilated and instrumented pigs prone to normovolaemia and hypovolaemia by blood withdrawal. INTERVENTION: Abdominal banding gradually increased IAP in 5-mmHg steps up to 30 mmHg. MEASUREMENTS AND MAIN RESULTS: Variations in systolic pressure, pulse pressure, inferior vena cava flow, and pleural and transmural (LVEDPtm) left-ventricular end-diastolic pressure were recorded at each step. Systolic pressure variations were 6.1+/-3.1%, 8.5+/-3.6% and 16.0+/-5.0% at 0, 10, and 30 mmHg IAP in normovolaemic animals (mean+/-SD; p<0.01 for IAP effect). They were 12.7+/-4.6%, 13.4+/-6.7%, and 23.4+/-6.3% in hypovolaemic animals (p<0.01 vs normovolaemic group) for the same IAP. Fluctuations of the inferior vena cava flow disappeared as the IAP increased. Breath cycle did not induce any variations of LVEDPtm for 0 and 30 mmHg IAP. CONCLUSIONS: In this model, the systolic pressure and pulse pressure variations, and inferior vena cava flow fluctuations were dependent on IAP values which caused changes in pleural pressure swing, and this dependency was more marked during hypovolaemia. The present study suggests that dynamic indices are not exclusively related to volaemia in the presence of increased IAP. However, their fluid responsiveness predictive value could not be ascertained as no fluid challenge was performed.

Abdomen↗
PubMed2006

Comments on 'The influence of cardiac preload and positive end-expiratory pressure on the pre-ejection period'.

The pre-ejection period (PEP) has been described as a potential parameter for monitoring cardiac preload in deeply sedated mechanically ventilated patients. Other authors have recently suggested that PEP is not sensitive to the changes in intravascular volume status in mechanically ventilated pigs which underwent acute hemorrhage. The present comment is an analysis of this recent animal investigation.

Animals↗
PubMed2006

Continuous cardiac output monitoring after cardiopulmonary bypass: a comparison with bolus thermodilution measurement.

OBJECTIVE: The interchangeability of continuous measurement of cardiac output (CO) with the traditional bolus method in patients after cardiopulmonary bypass (CPB) is uncertain. DESIGN: Prospective observational clinical study. SETTING: A 20-bed surgical ICU at a university hospital. PATIENTS: Fourteen deeply sedated, ventilated, post-cardiac surgery patients, all equipped with a pulmonary artery catheter. INTERVENTIONS: Six hours after the end of the CPB, 56 simultaneous bolus and continuous measurements were compared by a linear regression analysis and Bland-Altman analysis. Bolus CO was estimated by averaging triplicate injections of 10 ml room-temperature NaCl 0.9%, delivered randomly during the respiratory cycle. A stringent maximum difference of 0.55 l min(-1) (about 10% of the mean bolus measured) was considered as a clinically acceptable agreement between the two types of measurements. To be interchangeable the limits of agreement (+/-2 SD of the mean difference between the two methods) should not exceed the chosen acceptable difference. MEASUREMENTS AND RESULTS: Continuous was correlated with bolus CO, with a correlation coefficient of r(2)=0.68. (p<0.01). The Bland-Altman analysis demonstrated an objective mean bias of 0.33+/-0.6 l min(-1) (confidence interval of -0.87-1.58) with 34% of measured values falling outside of the clinically acceptable limits. CONCLUSION: Our results suggest that, in the first 6 h after CPB, continuous and bolus CO determinations are not interchangeable; one third of the values obtained by continuous CO fell outside the strict limits of clinically useful precision.

Aged↗
PubMed2005

Transcutaneous PCO2 monitoring in critically ill adults: clinical evaluation of a new sensor.

OBJECTIVE: In critically ill patients, arterial blood gas analysis is the gold standard for evaluating systemic oxygenation and carbon dioxide partial pressure. A new miniaturized carbon dioxide tension Pco2-Spo2 single sensor (TOSCA, Linde Medical Sensors AG, Basel, Switzerland) continuously and noninvasively (transcutaneously) monitors both Paco2 and oxygen saturation by pulse oximetry (Spo2). The present study was designed to investigate the usability and the accuracy of this device in critically ill patients. DESIGN: Prospective clinical investigation. SETTING: A 20-bed, university-affiliated, surgical intensive care unit. PATIENTS: Patients admitted after major surgery, multiple trauma, or septic shock equipped with an arterial catheter. INTERVENTIONS: The heated (42 degrees C) sensor was fixed at the earlobe using an attachment clip. Transcutaneous Pco2 (TcPco2) measurements were correlated with Paco2 values (measured using a blood gas analyzer). In addition, the differences between Paco2 and TcPco2 values were evaluated using the method of Bland-Altman. MEASUREMENTS AND MAIN RESULTS: We studied 55 patients, aged 18-80 (mean 57 +/- 15) yrs. A total of 417 paired measurements were compared. Correlation between TcPco2 and Paco2 was r = .86 (p < .01) in the Paco2 range of 24-101 mm Hg. Mean bias (+/-sd) between the two methods of measurement (Bland-Altman analysis) was 1.2 +/- 6.0 mm Hg with TcPco2 slightly overestimating arterial carbon dioxide tension. Nineteen percent of the measured values were outside of the acceptable clinical range of agreement of +/-7.5 mm Hg. CONCLUSIONS: The present study suggests that Paco2 can be acceptably assessed by measuring TcPco2 using the TOSCA Pco2-Spo2 sensor.

Adult↗
PubMed2005

Pre-ejection period variations predict the fluid responsiveness of septic ventilated patients.

OBJECTIVES: In septic patients with acute circulatory failure, reliable predictors of fluid responsiveness are needed at the bedside. We hypothesized that the respiratory change in pre-ejection period (DeltaPEP) would allow the prediction of changes in cardiac index following volume administration in mechanically ventilated septic patients. DESIGN: Prospective clinical investigation. SETTING: A ten-bed hospital intensive care unit. PATIENTS: Patients admitted after septic shock equipped with an arterial catheter. INTERVENTIONS: Pre-ejection period (PEP)--defined as the time interval between the beginning of the R wave on the electrocardiogram and the upstroke of the radial arterial pressure curve (PEPKT) or the pulse plethysmographic waveforms (PEPPLET)--and cardiac index (transthoracic echocardiography-Doppler) were determined before and after volume infusion of colloid (8 mL x kg). DeltaPEP (%) was defined as the difference between expiratory and inspiratory PEP divided by the mean of expiratory and inspiratory values. Respiratory changes in pulse pressure (DeltaPP) was also measured. MEASUREMENTS AND MAIN RESULTS: : Twenty-two volume challenges were done in 20 deeply sedated patients. DeltaPEPKT, DeltaPEPPLET, and DeltaPP (measured in all patients) before volume expansion were correlated with cardiac index change after fluid challenge (r = .73, r = .67, and r = .70, respectively, p < .0001). Patients with a cardiac index increase induced by volume expansion > or = 15% and <15% were classified as responders and nonresponders, respectively. Receiver operating characteristic curves showed that the threshold DeltaPP value of 17% allowed discrimination between responder/nonresponder patients with a sensitivity of 85% and a specificity of 100%. For both DeltaPEPKT and DeltaPEPPLET, the best threshold value was 4% with a sensitivity-specificity of 92%-89% and 100%-67%, respectively. CONCLUSIONS: The present study found DeltaPEPKT and DeltaPEPPLET to be as accurate as DeltaPP in the prediction of fluid responsiveness in mechanically ventilated septic patients.

Adult↗
PubMed2005

Fluid responsiveness in spontaneously breathing patients: a review of indexes used in intensive care.

OBJECTIVE: In spontaneously breathing patients, indexes predicting hemodynamic response to volume expansion are very much needed. The present review discusses the clinical utility and accuracy of indexes tested as bedside indicators of preload reserve and fluid responsiveness in hypotensive, spontaneously breathing patients. DATA SOURCE: We conducted a literature search of the MEDLINE database and the trial register of the Cochrane Group. STUDY SELECTION: Identification of reports investigating, prospectively, indexes of fluid responsiveness in spontaneously breathing critically ill patients. All the studies defined the response to fluid therapy after measuring cardiac output and stroke volume using the thermodilution technique. We did not score the methodological quality of the included studies before the data analysis. DATA EXTRACTION: A total of eight prospective clinical studies in critically ill patients were included. Only one publication evaluated cardiac output changes induced by fluid replacement in a selected population of spontaneously breathing critically ill patients. DATA SYNTHESIS: Based on this review, we can only conclude that static indexes are valuable tools to confirm that the fluid volume infused reaches the cardiac chambers, and therefore these indexes inform about changes in cardiac preload. However, respiratory variation in right atrial pressure, which represents a dynamic measurement, seems to identify hypotension related to a decrease in preload and to distinguish between responders and nonresponders to a fluid challenge. CONCLUSIONS: Further studies should address the question of the role of static indexes in predicting cardiac output improvement following fluid infusion in spontaneously breathing patients.

Blood Volume Determination↗
PubMed2005

Misplacement of central vein catheters in patients with hemothorax: a new approach to resolve the problem.

BACKGROUND: In emergency and pre-hospital care, the verification of the correct position of a central venous catheter is based on the observation of blood color reflow as well as pressure changes with respiration. However, in trauma patient with hemothorax, these indices may not always be reliable signs as the catheter is in a blood-filled pleural space. METHODS: A review of reports published describing patients presenting hemothorax and equipped with central venous catheter wrongly assumed to be in the correct position was performed. RESULTS: Over 10 years, seven reports have been published and a last study was found in the references list of one of the reviews. CONCLUSION: In patients with hemothorax due to severe thoracic trauma or other causes, a delay in detection of incorrect placement of a central venous catheter may delay fluid resuscitation and decrease the chances of survival. In this situation, the use of portable ultrasound devices may be an useful method to increase success rate in catheter insertion.

Catheterization, Central Venous↗
PubMed2005

Primary aortoenteric fistula: should enhanced computed tomography be considered in the diagnostic work-up?

UNLABELLED: We present the case of a 66-yr-old woman who was admitted to a surgical intensive care unit with life-threatening rectal bleeding. Despite the use of angiography and repeated computed tomography scans, the diagnosis of a primary aortoduodenal fistula secondary to an abdominal aortic aneurysm was not made, leading to a delay in diagnosis until the time of surgery. The reliability of radiological investigations and the importance of being alert to the possibility of this extremely rare condition are discussed. IMPLICATIONS: We describe the delayed diagnosis of an aortoduodenal fistula related to an abdominal aortic aneurysm. We emphasize that computed tomography scan results may be unreliable for detecting this pathology in patients who are hemodynamically unstable.

Aged↗
PubMed2005

Does continuous positive airway pressure by face mask improve patients with acute cardiogenic pulmonary edema due to left ventricular diastolic dysfunction?

OBJECTIVE: Continuous positive airway pressure (CPAP) by face mask is an effective method of treating severe cardiogenic pulmonary edema (CPE). However, to our knowledge, no study has provided a precise evaluation of the effects of CPAP on cardiac function in patients presenting with CPE and preserved left ventricular (LV) function. DESIGN: Prospective observational clinical study. SETTING: A 14-bed, medical ICU at a university hospital. PATIENTS: Nine consecutive patients presenting with hypoxemic acute CPE. INTERVENTIONS: All patients were selected for 30 min of CPAP with 10 cm H(2)O by mask with fraction of inspired oxygen adjusted for a cutaneous saturation > 90%. Doppler echocardiography was performed before CPAP application and during the last 10 min of breathing with CPAP. Two-tailed, paired t-tests were used to compare data recorded at baseline (oxygen alone) and after CPAP. MEASUREMENTS AND RESULTS: Four patients presented CPE with preserved left ventricular (LV) function (a preserved LV ejection fraction [LVEF] > 45%, and/or aortic velocity time integral > 17 cm in the absence of aortic stenosis or hypertrophic cardiomyopathy). Oxygenation and ventilatory parameters were improved by CPAP in all patients. Hemodynamic monitoring and Doppler echocardiographic analysis demonstrated that in patients with preserved LV systolic function, mean arterial pressure and LV end-diastolic volume were decreased significantly by CPAP (p < 0.04). In patients with LV systolic dysfunction, CPAP improved LVEF (p < 0.05) and decreased LV end-diastolic volume (p = 0.001) significantly. CONCLUSION: CPAP improves oxygenation and ventilatory parameters in all kinds of CPE. In patients with preserved LV contractility, the hemodynamic benefit of CPAP results from a decrease in LV end-diastolic volume (preload).

Acute Disease↗
PubMed2005

Right atrial pressure: determinant or result of change in venous return?

According to the concept of Guyton, cardiac output is largely controlled by venous return, which is determined by the difference between mean systemic venous pressure and right atrial pressure. In the analysis of the venous return curve, other authors have suggested that right atrial pressure is the dependent variable and venous return is the independent variable (right atrial pressure decreased because cardiac output increased). The present report analyzes this historical debate, which has already lasted > 50 years.

Atrial Function, Right↗
PubMed2004

Transpulmonary lactate gradient after hypothermic cardiopulmonary bypass.

OBJECTIVE: Several studies demonstrated that the lungs could produce lactate in patients with acute lung injury (ALI). Because after cardiopulmonary bypass (CPB) some patients develop ALI, the effect of CPB on pulmonary lactate release was investigated. DESIGN: Prospective observational clinical study. SETTING: Twenty-beds, surgical ICU at a university hospital. PATIENTS: Sixteen deeply sedated, ventilated and post-cardiac surgery patients, all equipped with a pulmonary artery catheter. MEASUREMENTS AND RESULTS: Lactate concentration was measured using a lactate analyser in simultaneously drawn arterial (A) and mixed venous (V) blood samples. Three measurements per patients were taken at 30-min interval, after body temperature reached 37 degrees C. Concomitantly, measurements of cardiac output were also obtained. Pulmonary lactate release was calculated as the product of transpulmonary A-V lactate and cardiac index. The mean cardiopulmonary bypass duration was 100+/-44 min (SD), and the aortic cross-clamping time was 71+/-33 min. After CPB, lactate release was 0.136+/-0.210 mmol/min m(-2). These values were not correlated with cardiopulmonary bypass duration. CONCLUSION: The present study shows that in patients receiving mechanical ventilation after CPB, the lung is a source of lactate production. This pulmonary release was not dependent on cardiopulmonary bypass duration.

Aged↗
PubMed2004

The respiratory change in preejection period: a new method to predict fluid responsiveness.

The accuracy and clinical utility of preload indexes as bedside indicators of fluid responsiveness in patients after cardiac surgery is controversial. This study evaluates whether respiratory changes (Delta) in the preejection period (PEP; DeltaPEP) predict fluid responsiveness in mechanically ventilated patients. Sixteen postcoronary artery bypass surgery patients, deeply sedated under mechanical ventilation, were enrolled. PEP was defined as the time interval between the beginning of the Q wave on the electrocardiogram and the upstroke of the radial arterial pressure. DeltaPEP (%) was defined as the difference between expiratory and inspiratory PEP measured over one respiratory cycle. We also measured cardiac output, stroke volume index, right atrial pressure, pulmonary arterial occlusion pressure, respiratory change in pulse pressure, systolic pressure variation, and the Deltadown component of SPV. Data were measured without positive end-expiratory pressure (PEEP) and after application of a PEEP of 10 cmH2O (PEEP10). When PEEP10 induced a decrease of >15% in mean arterial pressure value, then measurements were re-performed before and after volume expansion. Volume loading was done in eight patients. Right atrial pressure and pulmonary arterial occlusion pressure before volume expansion did not correlate with the change in stroke volume index after the fluid challenge. Systolic pressure variation, DeltaPEP, Deltadown, and change in pulse pressure before volume expansion correlated with stroke volume index change after fluid challenge (r2 = 0.52, 0.57, 0.68, and 0.83, respectively). In deeply sedated, mechanically ventilated patients after cardiac surgery, DeltaPEP, a new method, can be used to predict fluid responsiveness and hemodynamic response to PEEP10.

Aged↗
PubMed2004

Is Dressler syndrome dead?

Post-acute myocardial infarction (AMI) syndrome was first described by Dressler in 1956. Its incidence has decreased in the reperfusion era, most likely because of the extensive use of thrombolysis and coronary balloon angioplasty, therapies that dramatically decreased the size of myocardial necrosis. The authors suggest that drugs that have been prescribed in previous decades as the post-AMI "standard-of-care," such as angiotensin-converting enzyme inhibitors, beta-blockers, and statins, may also play an important role in the disappearance of Dressler syndrome due to their immunomodulatory effects.

Fever↗