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Biomedical subjects

R C Bone

Publications and source records attributed to R C Bone.

At least 127 records · Page 7Linked to original sources
PubMed1990

Financial implications of ventilator care.

Mechanical ventilation is in the forefront of modern technologic advances. These advances can be life saving for some, death prolonging for others. As difficult medical, ethical, and economic issues are raised in relation to life-sustaining treatments, it is important to have as complete a data base as possible concerning costs and outcomes of mechanical ventilation, so that physicians, patients, families, and society as a whole can make appropriate decisions regarding its use.

Costs and Cost Analysis↗
PubMed1989

Determination of cardiac output in critically ill patients by dual beam Doppler echocardiography.

Recent technology in Doppler echocardiography has produced a dual beam Doppler instrument that is capable of insonating the total cross-sectional area of the ascending aorta. The purpose of this study was to evaluate the accuracy of this instrument in measuring cardiac output in critically ill patients by comparing results with those of the thermodilution-derived cardiac output. A technically adequate Doppler cardiac output measurement was attained in 71 (91%) of 78 patients. The range of thermodilution-derived cardiac output measurements was from 1.58 to 11.70 liters/min. To maximize thermodilution cardiac output reliability, several measurements were made for each patient. Those patients in whom the difference between the highest and lowest measurement varied by less than 10% from the averaged results were accepted into the 50 patient study. There was significant correlation between dual beam Doppler- and thermodilution-derived cardiac output (r = 0.96, SEE = 0.55 liters/min, p less than 0.0001). This study demonstrates that dual beam Doppler ultrasound is a promising noninvasive method of measuring cardiac output in the critically ill patient.

Acute Kidney Injury↗
PubMed1989

Successful weaning from mechanical ventilation. Strategies to avoid failure.

The majority of patients who require mechanical ventilation can be weaned quickly from the ventilator. Patients with severe lung disease and multisystem disease often require a more prolonged, gradual reduction of ventilatory support. Identification of patients who are ready to be weaned, correction of common problems that occur in weaning, and use of a standard approach during weaning trials can improve the likelihood of successful discontinuation of mechanical ventilation.

Humans↗
PubMed1989

Acoustic characteristics of speech following uvulopalatopharyngoplasty.

Selective uvulopalatopharyngoplasty has resulted in the improved management of sleep apnea; however, the effect of the surgery on speech has not been systematically evaluated. In this study, the speaking fundamental frequency, reading rate, and first and second formants of the vowels of four patients were measured acoustically presurgically and postsurgically. The results indicate that the length of time needed to read a passage was reduced in all four patients 2 weeks following surgery compared to the presurgical duration. In addition, the second formant of nine vowels studied was lower postsurgically. No changes in speaking fundamental frequency were found in three of the four patients; in the fourth, the speaking fundamental frequency was lower by approximately one semitone. Based on the reduced reading rates from the presurgical to the postsurgical conditions, changes in respiratory parameters in addition to vocal tract parameters warrant assessment when evaluating the speech of individuals prior to and following uvulopalatopharyngoplasty.

Aged↗
PubMed1989

Hepatic dysfunction in the adult respiratory distress syndrome.

Multiple organ system failure is a major cause of mortality in the adult respiratory distress syndrome (ARDS). We serially evaluated parameters of multiple organ function in 24 patients during the first week after the diagnosis of ARDS and related them to outcome. The adult respiratory distress syndrome was associated with sepsis (n = 16), postoperation (n = 7), and trauma (n = 1). Fourteen of the 24 patients (58 percent) died. Although there were no significant differences in the indices of pulmonary or renal dysfunction between survivors and nonsurvivors, evidence of hepatic dysfunction was different in the two groups. On the day we identified ARDS, serum bilirubin was 1.2 mg/dl +/- 0.9 mg/dl in patients who survived, and was 2.3 mg/dl +/- 2.8 mg/dl (chi +/- SD) in those who died. Initial serum glutamic oxalacetic transaminase (SGOT) and alkaline phosphatase levels were lower in survivors than in those who died (71 +/- 44 IU/L vs 399 +/- 807 IU/L, and 121 +/- 53 IU/L vs 269 +/- 243 IU/L, respectively). These abnormalities persisted during the first week of respiratory failure, with significant differences in serum bilirubin and alkaline phosphatase between survivors and nonsurvivors (p less than 0.01). The degree of pulmonary and renal dysfunction was similar in both groups. These data suggest that liver function may be a major determinant of survival in patients with the adult respiratory distress syndrome.

Aged↗
PubMed1989

Randomized double-blind, multicenter study of prostaglandin E1 in patients with the adult respiratory distress syndrome. Prostaglandin E1 Study Group.

Prostaglandin E1 (PGE1) was compared to placebo in a 100-patient (50 PGE1, 50 placebo) randomized, double-blind, clinical trial to determine whether PGE1 therapy enhances survival of patients with adult respiratory distress syndrome (ARDS) when infused through a central line at 30 ng/kg/min continuously for seven days. At 30 days postinfusion, 30 PGE1 and 24 placebo patients had died. Total deaths judged to be related to the syndrome were 32 and 28 in the PGE1 and placebo groups respectively at six months. We conclude that PGE1 did not enhance survival in patients with established ARDS. PGE1 augmented the hyperdynamic circulation of these patients by reducing systemic and pulmonary vascular resistance, which resulted in a reduction of blood pressures and increased stroke volume, cardiac output, and heart rate. An improvement in oxygen availability and oxygen consumption was observed with PGE1 therapy. PGE1 was associated with an increased incidence of diarrhea (six patients in the PGE1 group vs one in the placebo group, p less than 0.05). Other adverse effects included hypotension (ten patients in the PGE1 group vs seven in the placebo group), fever (six patients in the PGE1 group vs three in the placebo group), and non-fatal dysrhythmias (ten in the PGE1 group vs five in the placebo group).

Alprostadil↗
PubMed1989

An early test of survival in patients with the adult respiratory distress syndrome. The PaO2/FIo2 ratio and its differential response to conventional therapy. Prostaglandin E1 Study Group.

Patients with established adult respiratory distress syndrome (ARDS) have a mortality rate that exceeds 50 percent. We analyzed the magnitude of hypoxemia as manifest by the PaO2/FIO2 ratio and its early response to conventional therapy including positive end-expiratory pressure (PEEP) in the placebo group of a large multicenter study. The PaO2/FIO2 ratio was not different at the time of diagnosis of ARDS in those patients who lived compared to those who subsequently died. After one day of conventional therapy including PEEP, those patients who survived increased their PaO2/FIO2 ratio. The nonsurvivors did not improve over a seven-day course. The difference in the PaO2/FIO2 ratio was significant throughout the seven-day observation period. We conclude that the early response to conventional therapy picks a patient population with a good prognosis and can be used as a test of likely survival from ARDS.

Alprostadil↗
PubMed1989

Long-term outcomes for elderly survivors of prolonged ventilator assistance.

Care of ventilator-dependent patients requires considerable resources, yet the long-term outcomes of this type of care have rarely been described. We retrospectively investigated the posthospital course of elderly patients who survived an episode of prolonged ventilator dependency to describe survival rates, subsequent use of health care resources, and functional abilities. Our data suggest that the use of prolonged mechanical ventilation in the elderly produces few survivors at considerable expense. Poor overall outcomes occurred despite considerable consumption of medical and nursing resources by the survivors.

Aged↗
PubMed1989

Prostaglandins, cyclo-oxygenase inhibitors, and thromboxane synthetase inhibitors in the pathogenesis of multiple systems organ failure.

The role of the various cyclo-oxygenase products of arachidonic acid metabolism in the production of the pathologic, physiologic, hemodynamic, and metabolic derangements of sepsis has been reviewed and there is a wide variation in different species and with different models of sepsis. The relationship of these potential mediators cannot be definitely determined. There is much circumstantial evidence that would incriminate the various arachidonic metabolites in the production of the sepsis manifestations; however, we must keep in mind that this may only be "guilt by association." Clearly, the available evidence does suggest that there is some role played by TXA2 and PGI2 in the physiologic and hemodynamic manifestations of sepsis, but the exact role remains undetermined.

Animals↗
PubMed1989

The septic syndrome. Definition and clinical implications.

The septic syndrome can be defined using clinical criteria in patients with clinical evidence of an infectious process. The other criteria include fever or hypothermia, tachypnea, tachycardia, and evidence of impaired organ perfusion or function as manifested by either altered mentation, hypoxemia, elevated plasma lactate, or oliguria. A multicenter trial using these criteria found positive blood cultures in 45 per cent of 382 patients. The mortality rate was approximately 30 per cent and 25 per cent of the patients developed ARDS. With respect to these characteristics, this septic syndrome population was very similar to the more traditionally defined populations with sepsis. Using the septic syndrome definition may allow for earlier detection of septic patients and possibly allow for earlier therapeutic intervention. The septic syndrome may help identify a population of patients at risk for the various complications of sepsis (that is, ARDS), aid in the search for pathophysiologic mechanisms, and allow for pharmacological trials earlier in the disease process.

Bacterial Infections↗
PubMed1989

Ventilatory support in the management of septic patients.

The use of mechanical ventilation in septic patients with or without ARDS remains under the category of supportive care. It is the task of clinicians to properly manage the ventilated patient and to prevent complications and treat them as soon as possible, if they arise. All clinicians eagerly await the introduction of agents that will either attenuate the inflammatory response in patients with the septic syndrome prior to the development of ARDS or assist in the healing of the acute injury.

Humans↗
PubMed1989

Sepsis syndrome: a valid clinical entity. Methylprednisolone Severe Sepsis Study Group.

The sepsis syndrome represents a systemic response to infection and is defined as hypothermia (temperature less than 96 degrees F) or hyperthermia (greater than 101 degrees F), tachycardia (greater than 90 beat/min), tachypnea (greater than 20 breath/min), clinical evidence of an infection site and with at least one end-organ demonstrating inadequate perfusion or dysfunction expressed as poor or altered cerebral function, hypoxemia (PaO2 less than 75 torr), elevated plasma lactate, or oliguria (urine output less than 30 ml/h or 0.5 ml/kg body weight.h without corrective therapy). One hundred ninety-one patients with the sepsis syndrome were evaluated prospectively and comprised the placebo group of a multicenter trial of methylprednisolone in sepsis syndrome and septic shock. Forty-five percent of the patients were found to be bacteremic. Thirty-six percent of the patients were in septic shock (sepsis syndrome plus a systolic BP less than 90 mm Hg or a decrease from baseline in systolic BP greater than 40 mm Hg) on study entry. An additional 23% of the patients developed shock after admission with 70% doing so within 24 h of study entry. Shock reversal occurred with a 73% frequency. Twenty-five percent of the patients developed the adult respiratory distress syndrome (ARDS). Mortality for the patients with sepsis syndrome who did not develop shock was 13%. Mortality for the groups of patients with shock on admission and shock postadmission was 27.5% and 43.2%, respectively. Forty-seven percent of the bacteremic patients developed shock after study admission compared to 29.6% of the nonbacteremic patients (p less than .05).(ABSTRACT TRUNCATED AT 250 WORDS)

Body Temperature↗
PubMed1988

Effects of ibuprofen on neutrophil function and acute lung injury in canine endotoxin shock.

The role of the polymorphonuclear leukocyte in the development of acute lung injury has been the subject of much controversy. Experimental lung injury is associated with peripheral leukopenia and the intrapulmonary sequestration of leukocytes. We have previously shown that ibuprofen, a nonsteroidal anti-inflammatory drug, can improve the hemodynamic alterations of canine endotoxin shock. Ibuprofen has also been found to decrease leukocyte adherence. We investigated the dose response of ibuprofen on the increased neutrophil adherence and the extent of lung injury associated with canine endotoxin shock. Single doses of ibuprofen (1, 5, 10, and 20 mg/kg iv) were administered 15 min after Escherichia coli endotoxin. Endotoxemia resulted in leukopenia and an increased neutrophil adherence in both aortic and pulmonary artery blood. Endotoxin-treated animals exhibited increased neutrophils in the bronchoalveolar lavage fluid, a marker of lung injury. The 20-mg/kg ibuprofen dose decreased aortic granulocyte adherence at 30 min, while all ibuprofen doses decreased the aortic adherence at 120 min. The increased pulmonary artery neutrophil adherence was not affected by ibuprofen. Histologically, lung injury was manifested by intravascular leukostasis. Ibuprofen treatment did not affect the histologic or morphometric extent of the lung injury. The leukopenia and increased neutrophil adherence occur rapidly after endotoxemia and are associated with subsequent intravascular sequestration of leukocytes. Agents designed to prevent lung injury must either be given before the insult or be able to block the effects of the toxic products released by the activated granulocytes.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗
PubMed1988

Low dose ibuprofen reverses the hemodynamic alterations of canine endotoxin shock.

The dose response of the nonsteroidal anti-inflammatory drug, ibuprofen, was evaluated in order to determine the most efficacious dose in the treatment of canine endotoxin shock. Fifteen minutes after an infusion of Escherichia coli endotoxin, four groups of dogs were given a single iv dose of 1, 5, 10, or 20 mg/kg of ibuprofen. These groups were compared to endotoxin only and saline control groups. All ibuprofen doses significantly improved the systolic, diastolic, and mean systemic arterial BP. The improvement in systemic BP was accompanied by an increase in the systemic vascular resistance. Pulmonary vascular pressures and resistance also increased after ibuprofen administration. The lack of a dose response and the demonstrated beneficial effect of low dose ibuprofen in the reversal of the hypotension associated with experimental canine endotoxin shock lead us to recommend the use of low dose ibuprofen for future endotoxin and sepsis studies. Use of low dose ibuprofen might have less of an effect on renal perfusion and would therefore be more likely to produce the beneficial hemodynamic response without compromising renal function.

Animals↗