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Biomedical subjects

P J Papadakos

Publications and source records attributed to P J Papadakos.

At least 19 recordsLinked to original sources
PubMed2000

Effects of propofol containing EDTA on mineral metabolism in medical ICU patients with pulmonary dysfunction.

OBJECTIVE: To determine whether the addition of disodium edetate (EDTA) to propofol significantly alters mineral metabolism, adverse events, and outcome in critically ill medical patients with acute pulmonary dysfunction. DESIGN: Multicentre, double-randomised, double-blind, comparative trial. SETTING: Medical intensive care units of 5 health centres. PATIENTS: A total of 85 haemodynamically stable men and women aged 18-81 years who had pulmonary dysfunction or adult respiratory distress syndrome as a primary diagnosis or complication and who were expected to require at least 48 hours of sedation and mechanical ventilation. INTERVENTIONS: Patients were randomised to receive propofol with or without EDTA and then to 1 of 2 sedation levels: light (Modified Ramsay Sedation Scale [MRSS] score of 2 to 3) or deep (MRSS score of 4 to 5). Propofol was administered by continuous infusion at an initial rate of 5 microg/kg per min and titrated as needed. MEASUREMENTS AND RESULTS: Approximately 63 % of patients had a high severity of illness as indicated by an Acute Physiology and Chronic Health Evaluation II score > or = 19. As expected, these patients had a higher mortality rate but did not require a higher dose of propofol or propofol with EDTA. Extensive evaluation of cation homeostasis showed that ionised calcium and magnesium concentrations remained remarkably stable during treatment. Total calcium concentration was low as a result of hypoalbuminemia. Parathyroid hormone (PTH) concentration was elevated in both study groups at baseline, on day 4, and at the end of sedation. There were no significant differences in electrolyte levels and no progression to renal dysfunction. There were also no significant differences in haemodynamic or adverse-event profiles. Treatment-related adverse events occurred in 5 patients in each group; 4 of these (in 3 patients receiving propofol and 1 patient receiving propofol with EDTA) were considered serious. Because a large percentage of patients experienced a change in sedation level, no analyses were performed using sedation level. CONCLUSIONS: The addition of EDTA to propofol does not alter calcium and magnesium homeostasis in critically ill patients with acute pulmonary dysfunction. The reason for the elevation in PTH concentrations in such patients is not known.

Adult↗
PubMed1997

Training requirements for pulmonary artery catheter utilization in adult patients.

OBJECTIVE: To review the literature addressing the issue of training requirements for pulmonary artery catheter (PAC) utilization in adult patients. DATA SOURCE: All pertinent English language articles dealing with training requirements for pulmonary artery catheterization were retrieved from 1984 through 1997. STUDY SELECTION: Articles were chosen if issues related to training and pulmonary artery catheterization were studied or reviewed. DATA EXTRACTION: From the articles selected, information about PAC training was obtained. DATA SYNTHESIS: The PAC is a commonly employed monitoring tool in the management of critically ill patients. Recent publications have strongly implied that PAC monitoring is associated with an increased morbidity and no notable clinical benefit. In response to these findings, the value of PAC monitoring has been questioned. The benefit assessment of any technology on clinical outcome presumes that the care provider possesses the skills and knowledge to optimally utilize the data obtained and simultaneously minimize the potential complications. Several recent articles have addressed physician and nurse knowledge as it pertains to PAC monitoring. The results of these studies are quite alarming. Marked deficiencies of knowledge were noted particularly in area of data interpretation and patient management. Extrapolating from their conclusions, it appears that any effort to proactively assess the value of PAC monitoring will be compromised until attempts are made to standardize and optimize the clinical skills of those involved in utilization of the technology. This article provides a proposed program for clinical education and raises the question regarding the necessity of demonstrated proficiency. CONCLUSION: Training, credentialing, and continued quality improvement related to PAC should be improved.

Catheterization, Swan-Ganz↗
PubMed1996

High-inflation pressure and positive end-expiratory pressure. Injurious to the lung? Yes.

There is a growing body of evidence suggesting that high levels of inflation pressure and high levels of PEEP may be injurious to lung tissue and other organ systems. Limiting peak alveolar pressures below 35 cm H2O may help in avoiding these injuries. The findings have led to the development of a lung-protective strategy that is based on physiologic parameters. This strategy, often using permissive hypercapnia and pressure-limited modes of ventilation, may gain widespread use in the near future. If this strategy reduces barotrauma, a reduction in the length of time on mechanical ventilation and mortality rates can be anticipated. At our center we routinely initiate mechanical ventilation in patients with acute lung injury, using tidal volumes of approximately 6 mL/kg. This may be decreased further if peak alveolar pressures exceed 30 to 35 cm H2O. PEEP is added to maximize alveolar recruitment and oxygenation. Optimal PEEP is located at the inflection point of the respiratory compliance curve. Usually a PEEP of 8 to 12 cm H2O is sufficient. Although we usually initiate mechanical ventilation with a volume-cycled mode, we are not hesitant to switch rapidly to a pressure-limited mode if results are unsatisfactory. We believe that more attention to the potential harmful effects of pressure and volume on lung architecture may result in further improvement of survival in patients with acute respiratory failure.

Barotrauma↗
PubMed1996

The role of calcium-channel antagonists in solid organ transplantation.

Calcium-channel antagonists play a role not only in the management of cardiovascular disease, but they may also play a role in solid organ transplantation. Part of the success of solid organ transplantation over the last several years has been the development of potent immunosuppressive agents such as cyclosporine A and tacrolimus. The calcium-channel antagonists have been shown to decrease cyclosporine A-induced nephrotoxicity by blocking the vasoconstrictive effects of endothelin and thromboxane A2 on the afferent arteriole induced by this agent. The role of calcium antagonists in avoiding tacrolimus-induced nephrotoxicity has not been studied to date. Calcium antagonists have been shown to have an immune-modulating effect as well, via inhibition of calcium-mediated lymphocyte proliferation. This immune-modulating effect has resulted in a decreased incidence of acute rejection in those patients receiving concomitant cyclosporine and calcium antagonists. A third role for calcium antagonists in organ transplantation has been as an additive to organ preservation solutions to avoid calcium-mediated ischemic damage. Despite several successful investigations demonstrating a role for calcium antagonists in solid organ transplantation, widespread acceptance of such a role awaits larger randomized clinical trials.

Animals↗
PubMed1995

Dopexamine hydrochloride in septic shock: effects on oxygen delivery and oxygenation of gut, liver, and muscle.

It has been suggested that septic shock is a disorder of microvascular autoregulation. Tissue blood flow is modulated by the state of activation of upstream endothelial receptors controlling the vascular smooth muscle tone. Because vascular receptor populations vary between organs, it should be expected that vasoactive drugs affect tissue oxygenation differently in different organs. We studied the effects of dopexamine HCl (a novel inotrope) and septic shock on oxygen delivery as well as tissue Po2 in gut, liver, and skeletal muscle in anesthetized rabbits. Employing the thermodilution technique, cardiac output was measured across the pulmonary bed and used to calculate oxygen delivery. Three eight-channel Mehrdraht Dortmund Oberfläche oxygen electrodes were placed on gut serosa, liver, and skeletal muscle surfaces, respectively, and sufficient readings were obtained to calculate tissue Po2 distributions. During septic shock mean arterial pressure, cardiac output, oxygen delivery, and mean tissue Po2 decreased in all organs. Our results suggest that the observed changes in tissue oxygenation during septic shock were caused by defective regulation of microvascular blood flow. In conclusion, during baseline conditions dopexamine HCl caused no statistically significant changes in tissue oxygenation in any organ, except in skeletal muscle at 10 micrograms/kg/min when tissue Po2 increased. During septic shock, however, dopexamine HCl improved oxygenation in all three organs in a dose-dependent manner.

Animals↗
PubMed1995

Barbiturates, neuroleptics, and propofol for sedation.

In a modern, hectic, and stressful intensive care unit, sedation is an important aspect of care, and every nurse and physician in a critical care setting must be familiar with it. This article describes older modalities of sedation, including barbiturates and neuroleptics, and compares them to a more recently developed drug, propofol.

Antipsychotic Agents↗
PubMed1994

Blunt traumatic rupture of the heart, pericardium, and supradiaphragmatic inferior vena cava: case report.

Before 1955 blunt traumatic ruptures of the heart and pericardium were reported almost exclusively in autopsy reports. Since then, because of improved prehospital care and early triage, it has been demonstrated that injuries resulting in rupture of the heart and pericardium are no longer always fatal. We present a case of a patient who arrived at the hospital with increasing abdominal girth and a tender abdomen who on exploration was found to have a tear of the pericardium and atrial appendage compounded by a supradiaphragmatic tear of the inferior vena cava.

Accidents, Traffic↗
PubMed1994

Pressure-controlled inverse-ratio ventilation in children with acute respiratory failure.

We report the use of pressure-controlled inverse-ratio ventilation in two children with acute respiratory failure who were failing conventional mechanical ventilation. The children had subsequent improvement in oxygenation and ventilation without hemodynamic compromise. Pressure-controlled inverse-ratio ventilation was well tolerated by one patient who had increased intracranial pressure secondary to head injury. We were able to successfully hyperventilate, improve oxygenation and control intracranial pressure in this patient while using pressure-controlled inverse-ratio ventilation, which may prove to be an alternative method of ventilation for children with severe lung disease.

Acute Disease↗
PubMed1993

Adult respiratory distress syndrome: a consideration with rapid respiratory decompensation in association with preeclampsia.

Adult respiratory distress syndrome, presenting as rapid respiratory decompensation in the setting of preeclampsia at 36 weeks of gestation, was managed by early hemodynamic monitoring with pulmonary artery catheterization. With confirmation of the diagnosis of preeclampsia the patient was delivered promptly; improvement of her respiratory failure was observed within 48 hours. Consideration of adult respiratory distress syndrome in the setting of preeclampsia is discussed, with emphasis on early confirmation of the diagnosis and determination of the precise mechanisms of pulmonary edema.

Adolescent↗
PubMed1991

Extensive pulmonary embolism presenting as severe adult respiratory distress syndrome after surgical resection of a cornual pregnancy.

A rare case of severe adult respiratory distress syndrome associated with a Po2 of 9 mm Hg after surgical resection of a cornual pregnancy at 10 weeks' gestation was treated successfully with positive end-expiratory pressure. The underlying cause, extensive pulmonary embolism, was subsequently revealed. The patient survived without residual brain damage. The possible causes of adult respiratory distress syndrome in pregnancy are discussed.

Adult↗
PubMed1991

The use of pressure-controlled inverse ratio ventilation in the surgical intensive care unit.

A key element in the treatment of Adult Respiratory Distress Syndrome (ARDS) is improvement in oxygen delivery to match metabolic demands. Conventional modes of ventilation have decreased mortality (50%) very little. We have done a retrospective analysis of 30 surgical patients who were treated with pressure-controlled inverse ratio ventilation. Mortality was 10%. Arterial oxygenation improved from 40.8 +/- 12.2 mm Hg to 138 +/- 47.2 mm Hg, while PCO2 decreased from 37.8 +/- 7.6 mm Hg to 31.1 +/- 5.9 mm Hg. Simultaneously, with the use of pressure-controlled inverse ratio ventilation, minute ventilation could be decreased by 30%, which may be secondary to increased O2 delivery to the tissue. Our data indicate that pressure-controlled inverse ratio ventilation may be beneficial to surgical patients with ARDS.

Adolescent↗
PubMed1991

Effects of dopamine and dobutamine on skeletal muscle oxygenation in normoxemic rats.

The effects of two vasoactive drugs, dopamine and dobutamine, on skeletal muscle tissue oxygenation were studied in a normoxemic rat model. It is usually claimed that drugs may increase or decrease oxygen delivery to tissues. However, this claim is only valid on the global level. Our interest is directed towards individual organs. Two groups of rats (n = 7 each) were studied. One group received dopamine, the other dobutamine. Blood gases, hematocrits, and mean arterial blood pressures were measured in addition to tissue pO2. Infusion of dopamine 2.5 micrograms/kg/min resulted in a statistically significant decrease in skeletal muscle pO2. Higher doses of dopamine, and all doses of dobutamine, did not influence pO2 at all. The results raise the question of whether blood flow to vital organs may be negatively affected by dopamine 2.5 micrograms/kg/min. Direct measurements of tissue oxygenation are warranted in, e.g., the liver and gut.

Animals↗
PubMed1990

Low sensitivity of the anion gap as a screen to detect hyperlactatemia in critically ill patients.

The anion gap is commonly used as a screening test for the presence of lactic acidosis. Analysis of the distribution of anion gaps for 56 adult surgical ICU patients with peak blood lactate levels greater than or equal to 2.5 mmol/L showed the anion gap to be an insensitive screen for elevated lactate in a critically ill, hospitalized population. All patients (11/11) with a peak lactate greater than or equal to 10 mmol/L had an anion gap greater than or equal to 16 mmol/L; however, 50% (6/12) of patients with lactates between 5.0 and 9.9 mmol/L and 79% (26/33) of those with lactates between 2.5 and 4.9 mmol/L had anion gaps less than 16 mmol/L. Hyperlactatemia was associated with considerable mortality at all levels: 100% among patients with lactate levels greater than or equal to 10 mmol/L, 75% between 5.0 and 9.9 mmol/L, and 36.4% between 2.5 and 4.9 mmol/L. Acidosis (pH less than 7.30) did not significantly alter mortality by lactate level. The observation that, for 57% of patients in this study, an elevated lactate level was not accompanied by an elevated anion gap suggests that hyperlactatemia should be included in the differential diagnosis of nonanion gap acidosis.

Acid-Base Equilibrium↗