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Biomedical subjects

K Safcsak

Publications and source records attributed to K Safcsak.

13 recordsLinked to original sources
PubMed2001

Mathematical coupling does not explain the relationship between right ventricular end-diastolic volume and cardiac output.

OBJECTIVE: To evaluate the clinical significance of mathematical coupling on the correlation between cardiac output and right ventricular end-diastolic volume (RVEDV) through measurement of cardiac output by two independent techniques. DESIGN: Prospective, observational study. SETTING: Surgical intensive care unit in a level 1 trauma center. PATIENTS: Twenty-eight critically ill surgical patients who received mechanical ventilation and hemodynamic monitoring with a pulmonary artery catheter. INTERVENTIONS: A pulmonary artery catheter designed to measure right ventricular ejection fraction (RVEF) and cardiac output by the intermittent bolus thermodilution (TDCO) method and continuous cardiac output by the pulsed thermal energy technique was placed. A computerized data logger was used to collect data simultaneously from the RVEF/TDCO system and the continuous cardiac output system. MEASUREMENTS AND MAIN RESULTS: Two hundred forty-nine data sets from 28 patients were compared. There is statistical correlation between TDCO and continuous cardiac output measurements (r = 0.95, p < 0.0001) with an acceptable bias (-0.11 L/min) and precision (+/-0.74 L/min). The correlation was maintained over a wide range of cardiac outputs (2.3-17.8 L/min). There is a high degree of correlation between RVEDV and both TDCO (r = 0.72, p < 0.0001) and independently measured continuous cardiac output (r = 0.68, p < 0.0001). These correlation coefficients are not statistically different (p = 0.15). CONCLUSIONS: The continuous cardiac output technique accurately approximates cardiac output measured by the TDCO method. RVEDV calculated from TDCO correlates well with both TDCO and independently measured continuous cardiac output. Because random measurement errors of the two techniques differ, mathematical coupling alone does not explain the correlation between RVEDV estimates of preload and cardiac output.

Adult↗
PubMed1999

Preload assessment in patients with an open abdomen.

BACKGROUND: Intra-abdominal hypertension and abdominal compartment syndrome cause significant morbidity and mortality in surgical and trauma patients. Maintenance of intravascular preload and use of open abdomen techniques are essential. The accuracy of pulmonary artery occlusion pressure (PAOP) and central venous pressure (CVP) in patients with intra-abdominal hypertension has been questioned. METHODS: Twenty surgical and trauma patients with intra-abdominal hypertension requiring open abdominal decompression were monitored using volumetric thermodilution pulmonary artery catheters. Hemodynamic, oxygenation, inspiratory, and intravesicular pressure measurements were collected prospectively. PAOP, CVP, and right ventricular end-diastolic volume index (RVEDVI) were compared as estimates of preload status. RESULTS: Multiple regression analysis demonstrated that cardiac index correlated significantly better with RVEDVI (r = 0.69) than with PAOP (r = -0.27) or CVP (r = -0.28) during resuscitation after open abdominal decompression (p < 0.0001). CONCLUSION: RVEDVI is superior to PAOP and CVP as an estimate of preload status in patients with an open abdomen.

Adolescent↗
PubMed1999

Right heart volumetric monitoring: measuring preload in the critically injured patient.

Accurate assessment of preload status is a major concern in the resuscitation of the critically injured patient. Of the three physiologic determinants of stroke volume, preload is the variable that is most frequently influenced by an insult or intervention or both in the trauma patient. In the critically injured patient, clinicians focus on the preload status to restore and maintain intravascular volume in attempts to optimize cardiac output and oxygen delivery. Until recently, efforts to measure and optimize ventricular preload have focused on intracardiac filling pressures (central venous pressure and pulmonary artery occlusion pressure). The purpose of this review is to discuss the application of volumetric measurements that provide a more accurate means of determining recruitable ventricular preload in the critically injured patient.

Acute Disease↗
PubMed1999

Air travel following traumatic pneumothorax: when is it safe?

The safety of air travel for patients sustaining a recent traumatic pneumothorax has long been a subject of debate. The Aerospace Medicine Association has suggested that patients should be able to fly 2 to 3 weeks after radiographic resolution of their pneumothorax. To validate these recommendations, a prospective study was performed. Twelve consecutive patients with recent traumatic pneumothorax expressing a desire to travel by commercial airline were evaluated. Ten patients waited at least 14 days after radiographic resolution of their pneumothorax before air travel (mean, 17.5+/-4.9 days), and all were asymptomatic in-flight. One of two patients who flew earlier than 14 days developed respiratory distress in-flight, with symptoms suggestive of a recurrent pneumothorax. We conclude that commercial air travel appears to be safe 14 days following radiographic resolution of a traumatic pneumothorax.

Adult↗
PubMed1998

Right ventricular end-diastolic volume index as a predictor of preload status in patients on positive end-expiratory pressure.

OBJECTIVE: To evaluate the clinical utility of right ventricular end-diastolic volume index (RVEDVI) and pulmonary artery occlusion pressure (PAOP) as measures of preload status in patients with acute respiratory failure receiving treatment with positive end-expiratory pressure. DESIGN: Prospective, cohort study. SETTING: Surgical intensive care unit in a Level I trauma center/university hospital. PATIENTS: Sixty-four critically ill surgical patients with acute respiratory failure. INTERVENTIONS: All patients were treated for acute respiratory failure with titrated levels of positive end-expiratory pressure (PEEP) with the goal of increasing arterial oxygen saturation to > or =0.92, reducing FIO2 to <0.5, and reducing intrapulmonary shunt to < or =0.2. Serial determinations of RVEDVI, PAOP, and cardiac index (CI) were recorded. MEASUREMENTS AND MAIN RESULTS: Two hundred-fifty sets of hemodynamic variables were measured in 64 patients. The level of PEEP ranged from 5 to 50 cm H2O (mean 12+/-9 [SD] cm H2O). At all levels of PEEP, CI correlated significantly better with RVEDVI than with PAOP. At levels of PEEP > or =15 cm H2O, CI was inversely correlated with PAOP, but remained positively correlated with RVEDVI. CONCLUSIONS: CI correlates significantly better with RVEDVI than PAOP at all levels of PEEP up to 50 cm H2O. RVEDVI is a more reliable predictor of volume depletion and preload recruitable increases in CI, especially in patients receiving higher levels of PEEP where PAOP is difficult to interpret.

Acute Disease↗
PubMed1996

High-level positive end expiratory pressure management in the surgical patient with acute respiratory distress syndrome.

Although the exact incidence of ARDS is not know, it is frequently reported that there are 150,000 cases in the United States each year. Despite major advances in medical and respiratory intensive care, the mortality for patients with ARDS remains exceedingly high and has not changed appreciably from the 50% to 75% reported during the last 25 years. Currently there is no widespread, acceptable, specific therapeutic approach or agent available for the prevention or treatment of ARDS. Clinical management remains entirely supportive in nature. Although most practitioners agree that patients with severe ARDS require mechanical ventilation to maintain adequate gas exchange, controversies center on the amount of supplemental oxygen, level of positive end expiratory pressure (PEEP), and mode of ventilation needed to increase patient survival but reduce ventilator-associated complications. This review provides supportive evidence for the use of high-level PEEP (more than 15 cm H20) in the care of the surgical patient with severe ARDS.

Critical Care↗
PubMed1995

Survival in patients with severe adult respiratory distress syndrome treated with high-level positive end-expiratory pressure.

OBJECTIVE: To assess the mortality rate and complications in a population of surgical patients with severe adult respiratory distress syndrome (ARDS) treated with positive end-expiratory pressure (PEEP) of > 15 cm H2O in an attempt to reduce intrapulmonary shunt to approximately 0.20 and reduce FIO2 to < 0.50. DESIGN: Retrospective review of patients treated by a standardized ventilatory support protocol at the time of their illness. SETTING: A 24-bed surgical intensive care unit in a university medical center. PATIENTS: All patients admitted to the surgical intensive care unit during a 34-month period who met the criteria for severe ARDS (Pao2 of < or = 70 torr [< or = 9.3 kPa] on an FIO2 of > or = 0.50, diffuse interstitial and/or alveolar infiltrates on chest radiograph, decreased lung compliance, no evidence of congestive heart failure, and a likely predisposing etiology) were evaluated. Patients treated with PEEP of > 15 cm H2O were selected for this review. INTERVENTIONS: Patients were treated by a protocol to achieve oxygenation end points, which consisted of maintaining arterial oxyhemoglobin saturation (as determined by pulse oximetry of > or = 0.92), while reducing FIO2 to < 0.50 and decreasing intrapulmonary shunt fraction to < or = 0.20 by adding PEEP. With the exception of patients with suspected intracranial hypertension related to closed-head injury, low-rate intermittent mandatory ventilation was the primary mode of ventilation. Pressure-support ventilation was added, when needed, to improve patient comfort, enhance spontaneous tidal volume, or improve CO2 excretion. MEASUREMENTS AND MAIN RESULTS: Eighty-six patients with severe ARDS were treated with a PEEP of > 15 cm H2O. Nineteen of these patients died early of severe closed-head injury or massive uncontrollable hemorrhage and were excluded from the evaluation. The remaining 67 patients had a mean Lung Injury Score of 3.3 during their treatment with high PEEP. Twenty (30%) of 67 patients died. Eight of the deaths occurred after decrease of ventilatory support and with acceptable blood gases. The other 12 patients who died had continued oxygenation deficits and received increased levels of ventilatory support at the time of death. Twenty-six (39%) of 67 patients had radiographic manifestations of barotrauma (pneumothorax, subcutaneous emphysema, etc.) related to their primary injuries or to complications related to central venous catheter placement. Seven (17%) of 41 patients developed clinical or radiographic signs of barotrauma while receiving high-level PEEP. The hemodynamic effects of increased airway pressure were managed with fluids and inotropic agents, when necessary, and did not limit the application of PEEP to reach the defined end point of treatment. CONCLUSIONS: This subset of patients with severe ARDS treated with high-level PEEP had a mortality rate lower than those rates previously reported by other researchers using more conventional ventilatory support and resuscitation techniques. FIO2 may be significantly reduced and PaO2 may be maintained at acceptable values by decreasing intrapulmonary shunt fraction using high-level PEEP.

Adult↗
PubMed1994

Thermodilution right ventricular ejection fraction measurements: room temperature versus cold temperature injectate.

OBJECTIVE: To compare thermodilution right ventricular ejection fraction measurements using 10 mL room temperature injectate vs. 10 mL cold temperature injectate. DESIGN: Prospective, clinical study. SETTING: Adult surgical intensive care unit (ICU) in a university hospital. PATIENTS: Sixty adult surgical ICU patients requiring hemodynamic monitoring by a pulmonary artery catheter. INTERVENTIONS: Patients were in a supine position with the bed flat during thermodilution measurements. Four 10 mL room temperature injections were alternated with four 10 mL cold temperature injections. MEASUREMENTS AND MAIN RESULTS: One hundred eleven paired thermodilution right ventricular ejection fraction measurements were made in patients during a "steady state." There were no restrictions regarding body temperature, cardiac index, heart rate or rhythm. Injectate temperature was measured by an in-line temperature probe. Injections were synchronized with end-expiration of mechanical ventilator breaths. The first injection was deleted from each temperature group. Reproducibility of individual right ventricular ejection fraction measurements was assessed by calculating the mean variation of triplicate measurements in each temperature group. Mean values of room temperature measurements were compared with cold temperature measurements by Student's t-test. Linear regression analysis, bias, and precision were also calculated. There was no significant difference (p = .752) between mean right ventricular ejection fraction measurements determined with room temperature (23.9 +/- 1 degrees C) vs. cold temperature (8.0 +/- 1.1 degrees C) injectate. There was a high degree of correlation between measurements (r2 = .876, p < .001). The bias of room temperature measurements compared with cold temperature was -0.39% and the precision was +/- 3.3%. The mean variation between individual measurements in all room temperature and cold temperature right ventricular ejection fraction measurements was 9.7% and 8.0%, respectively. There was no significant difference and there was a high degree of correlation in mean right ventricular ejection fraction measurements when data were grouped according to body temperature, heart rate, cardiac index, right ventricular ejection fraction, central venous pressure, pulmonary vascular resistance index, right ventricular end-diastolic volume index, or right ventricular stroke work index. CONCLUSIONS: The results suggest that room temperature injectate may be used for right ventricular ejection fraction measurements in critically ill adult surgical patients. Utilizing room temperature injectate for right ventricular ejection fraction measurements may save time and costs in the critical care unit.

Adult↗
PubMed1992

High-level positive end-expiratory pressure management in trauma-associated adult respiratory distress syndrome.

This study evaluated the effect of high-level positive end-expiratory pressure (PEEP) on mortality, barotrauma, intrapulmonary shunt (Qsp/Qt), and oxygen delivery (DO2) in posttraumatic adult respiratory distress syndrome (ARDS). All hypoxemic trauma patients admitted to the surgical intensive care unit (SICU) in 1989-1990 who received PEEP greater than 15 cm H2O were included. The PEEP was titrated to achieve an intrapulmonary shunt (Qsp/Qt) of approximately 0.20, and FIO2 was weaned to less than 0.50. Hemodynamic and pulmonary variables at four distinct intervals were recorded. Fifty-nine patients received PEEP greater than 15 cm H2O. Of these, 19 patients died of severe head injury or uncontrollable hemorrhage (16 within 48 hours). Forty (29 male, 11 female) were evaluated in detail. The PEEP levels ranged from 18-50 cm H2O with a mean of 27. PaO2/FIO2 ratios and Qsp/Qt improved as PEEP therapy was titrated. Cardiac index and oxygen delivery were maintained or improved throughout PEEP therapy by transfusion and fluid resuscitation, with a mean maximum positive fluid balance of 21.1 L and an average of 51 units of blood and blood products transfused per patients during their SICU stay. Twenty-nine (73%) had evidence of barotrauma, the majority being pneumothoraces clearly related to the initial trauma. Only three (7.5%) had evidence of barotrauma not related to trauma or line insertion. Eight of 40 patients (20%) died. Mean ISS and RTS for the entire group were 32 and 5.88, respectively. We conclude that titration of PEEP to achieve a Qsp/Qt of approximately 0.20 is an attainable goal. This was accomplished with minimal hemodynamic effects or barotrauma and a low mortality rate.

Adolescent↗
PubMed1990

Use of recombinant human erythropoietin (r-HuEPO) in a Jehovah's Witness refusing transfusion of blood products: case report.

Recombinant human erythropoietin (r-HuEPO) administration to a Jehovah's witness refusing blood transfusions increased her nadir packed cell volume from 13% to 37% and reticulocyte count from 2% to 17.7%. R-HuEPO may provide an alternative safe and effective therapy in life-threatening anemia when blood transfusions are unacceptable to the patient.

Accidents, Traffic↗