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Biomedical subjects

T J Gallagher

Publications and source records attributed to T J Gallagher.

At least 37 records · Page 2Linked to original sources
PubMed1990

Five percent human albumin in lactated Ringer's solution for resuscitation from hemorrhagic shock: efficacy and cardiopulmonary consequences.

Using an ovine model of acute hemorrhagic shock, we evaluated the utility of 5% albumin in lactated Ringer's (5% ALR) solution as a resuscitation solution. After instrumentation and obtaining baseline values for BP, mean arterial pressure (MAP), pulmonary capillary wedge pressure (WP), CVP, cardiac output, extravascular lung water (EVLW), and blood gases (mixed venous and arterial), animals were rapidly exsanguinated to an MAP of 50 mm Hg. After 30 min at this pressure, measurements were repeated and 5% ALR was administered until two of three variables (WP, MAP, cardiac output) were restored to baseline values. The administration of 5% ALR was continued as needed to maintain baseline values of these variables. Sixty minutes later, data were again recorded. For induction of shock, 15.7 +/- 5.2 ml of blood/kg body weight was removed. Pulmonary artery pressure, WP, MAP, and cardiac output all significantly decreased with shock. After resuscitation, all values except MAP returned to baseline. The resuscitation volume of 5% ALR was 25.2 +/- 18.4 ml/kg. There were no changes in EVLW or intrapulmonary shunt. Oxygen delivery was significantly compromised during shock but returned to baseline after resuscitation. We conclude that in a model such as ours, 5% ALR can reverse the hemodynamic effects of acute hemorrhagic shock.

Acute Disease↗
PubMed1989

High-frequency percussive ventilation compared with conventional mechanical ventilation.

In seven patients with severe respiratory distress, conventional mechanical ventilation and PEEP were used initially for respiratory support, which was changed to high-frequency percussive ventilation (HFPV) at the same level of airway pressure and FIO2. During both modes of ventilation, patients could breathe spontaneously via a low-threshold demand valve. With HFPV, PaO2 improved significantly (p less than .01) compared with PaO2 during conventional methods. Cardiac output was unaffected by the change to HFPV.

Carbon Dioxide↗
PubMed1988

Experiments on the effects of hyperbaric oxygen on flap survival in the pig.

The use of hyperbaric oxygen has been advocated as a method of improving survival of ischemic flaps. Experiments were done in the pig using modern flap designs and hyperbaric oxygen protocols that have been reported to be effective in rodents. The results of these experiments indicate that hyperbaric oxygen is not effective in improving flap survival in the pig.

Animals↗
PubMed1988

Hemodynamic effects of nifedipine in a canine model of acid aspiration.

A solution of ethyl alcohol, polyethylglycol, and distilled water that did (n = 5) or did not (n = 5) contain 250 micrograms/kg of the calcium channel blocker, nifedipine, was infused into the right atrium in 10 healthy mongrel dogs. Hydrochloric acid (pH = 1.8), 2 ml/kg, was then instilled into both lungs of all dogs via the tracheal tube. Hemodynamic data were collected before and 10 minutes after nifedipine was infused and 10, 45, 90 and 180 minutes after acid was instilled into the lungs. Gas exchange, including PaO2 and venous admixture, did not differ between the two groups. However, after aspiration, oxygen delivery significantly improved in the dogs given nifedipine compared to oxygen delivery in those not treated with nifedipine. We conclude that, despite significant decreases in PaO2 and venous admixture, nifedipine can restore oxygen delivery back to normal levels.

Animals↗
PubMed1987

Effects of hetastarch resuscitation on extravascular lung water and cardiopulmonary parameters in a sheep model of hemorrhagic shock.

Eight sheep, weighing 29-71 kg, were used to evaluate the cardiopulmonary response to Hespan infusion following shock. Before shock was induced, mean arterial pressure (MAP), pulmonary capillary wedge pressure (PCWP), pulmonary artery pressure (PAP), cardiac output (CO), extravascular lung water (EVLW), colloid oncotic pressure (COP), and hemoglobin were measured and shunt, arteriovenous oxygen content difference (C[a - v]O2) and COP-PCWP gradient were calculated. The animals were bled to a MAP of 50 mmHg and that level was maintained for 30 min. At the end of that time, the data were collected again. The animals were resuscitated back to baseline values of PCWP, MAP, and CO with a 6% hydroxyethylstarch solution. With shock, PCWP, MAP, CO, and arterial pH decreased and C(a - v)O2 increased significantly (P less than 0.05). With resuscitation, PAP, PCWP and CO were significantly greater than baseline. Arterial pH was less than the baseline value but was within normal range. MAP did not return to preshock levels. EVLW and venous admixture did not change at any time. C(a - v)O2 returned to baseline with resuscitation. Volume of hetastarch infused was 29.1 +/- 10 cm3/kg. We conclude that hetastarch is an effective resuscitation solution in a model of hemorrhagic shock and appears to have no adverse cardiopulmonary effects.

Animals↗
PubMed1987

Influence of sterile protective sleeves on the sterility of pulmonary artery catheters.

Eighty-seven pulmonary artery catheters (PACs) with sterile protective sleeves were placed into 69 surgical ICU patients by one of the following two methods: through an introducer placed in a new, percutaneous site or by exchanging an indwelling catheter for an introducer. On removal, 5-cm catheter segments from the catheter tip and from within the introducer and sleeve, peripheral blood, and blood drawn from the PAC distal port were cultured quantitatively. Sleeve segment cultures were sterile if catheterization was less than 48 h and had been accomplished through a new percutaneous site. The risk of growing greater than 10(3) colonies on the tip and introducer segment increased to greater than 30% when PACs were left in over 96 h. The incidence of catheter-related bacteremia (CRB), defined as the simultaneous growth of identical organisms from the blood and the PAC tip, was 5.3% but may have been underestimated. CRB was associated with the use of corticosteroids (p = .009) and with cultures from any PAC segment growing more than 10(3) colonies (p less than .01). Although our data suggest that the use of the sterile protective sleeve is associated with a low risk of colonization, further study will be required to delineate the relationship between the use of protective sleeves and CRB.

Bacterial Infections↗
PubMed1987

Early bronchoscopy as a predictor of ventilatory support for burned patients.

Twenty-seven burned patients who had facial burns, hoarseness, or evidence of carbonaceous sputum or had been in a smoke-filled enclosed space underwent fiberoptic bronchoscopy at the time of admission. Airway severity was indexed (grades 1-5, grade 5 being the most severe). Fifteen nonsurvivors had a bronchoscopic index of 3.2 +/- 1.6 and 12 survivors an index of 3.4 +/- 1.2 (p greater than 0.05). No patient died of respiratory complications. Bronchoscopic index correlated poorly with the level of positive end expiratory pressure required to maintain oxygenation in any patient (r = 0.50). Likewise, bronchoscopic index did not correlate with duration of intubation in any survivor (r = 0.33). Immediate bronchoscopy after burn injury neither indicates the level of respiratory support that will be required nor predicts its duration.

Bronchoscopy↗
PubMed1987

Hypertonic saline as a resuscitation solution in hemorrhagic shock: effects on extravascular lung water and cardiopulmonary function.

To determine the effect of resuscitation with hypertonic saline on extravascular lung water, seven adult sheep were endotracheally intubated; mean arterial pressure (MAP), pulmonary artery pressure (PAP), pulmonary capillary wedge pressure (PCWP), and central venous pressure (CVP) were monitored. A 5-French, thermistor-tipped catheter was used to measure extravascular lung water (EVLW). Colloid oncotic pressure (COP), serum electrolytes and osmolality, and arterial and mixed venous blood gas tensions were measured. The COP-PCWP gradient and the shunt fraction (Qsp/Qt) were calculated. After baseline measurements, the animals were bled to an MAP of 50 mm Hg (blood volume removed, 16.2 +/- 3.6 ml/kg), which was maintained for 30 min, measurements then being repeated. Three percent sodium chloride solution was infused at 500 ml/15 min until two of three parameters--cardiac output (CO), PCWP, or MAP--were restored to baseline values. Data were recorded again and then 60 min later. No shed blood was reinfused. The total volume of hypertonic saline infused was 39 +/- 19 ml/kg. Pulmonary artery pressure did not vary throughout the study. PCWP, MAP, and CO were significantly lower than baseline (P less than 0.05) 30 min after bleeding but all except MAP returned to baseline with resuscitation. Throughout the study, EVLW did not vary despite a COP-PCWP gradient less than 4 mm Hg. Serum sodium levels and serum osmolality were significantly above baseline values after resuscitation. In this animal model of hemorrhagic shock, infusion of hypertonic saline effected resuscitation without compromising cardiopulmonary function or increasing EVLW.

Animals↗
PubMed1986

Continuous positive airway pressure and expiratory positive airway pressure increase functional residual capacity equivalently.

The effect of continuous positive airway pressure (CPAP) and expiratory positive airway pressure (EPAP) on functional residual capacity (FRC) of ten healthy, spontaneously breathing, lightly anesthetized intubated mongrel dogs was studied. The CPAP and EPAP at 5, 10, 15, and 20 cm H2O were alternately applied to all animals. Total (lung and chest wall) compliance, esophageal pressure, airway pressure, transpulmonary pressure, control FRC, and the change in FRC (delta FRC) were measured before and after each application of CPAP and EPAP. Neither expiratory transpulmonary pressure nor delta FRC with CPAP differed significantly from that with EPAP at all levels (p greater than 0.05). These data suggest that CPAP and EPAP, when applied at the same expiratory pressure, result in an equivalent increase in FRC due to passive mechanical distention of the lungs.

Animals↗
PubMed1985

Frequency and percent inspiratory time for high-frequency jet ventilation.

A variety of frequencies and percent inspiratory times (%TI) may be used for high-frequency jet ventilation (HFJV). Five physiologic criteria were used to evaluate various combinations of frequency and %TI: mean airway pressure (Paw), cardiac output, PaCO2, PaO2, and intrapulmonary shunt (Qsp/Qt). At a constant drive pressure, the effects of frequencies of 100, 200, 300, 450, 600, 750, and 900 cycle/min at %TI values of 20%, 30%, and 40% of the respiratory cycle were evaluated and compared with the effects of controlled mechanical ventilation (CMV) at 8 to 12 breath/min. Only at 200 cycle/min and 20% TI, were Paw, cardiac output, PaCO2, PaO2, and Qsp/Qt all the same as the CMV values. At 100 cycle/min and 20% TI, CO2 elimination increased without significantly affecting Paw, cardiac output, PaO2, or Qsp/Qt. These data suggest that HFJV might compromise one or more physiologic variables at certain combinations of frequency and %TI. Therefore, at a fixed drive pressure, there appears to be a narrow range of HFJV ventilator settings that should be considered.

Animals↗
PubMed1985

Hemodynamic effects of positive end-expiratory pressure during high-frequency ventilation.

We studied the intrapleural and hemodynamic effects of positive end-expiratory pressure (PEEP) during high-frequency ventilation (HFV) with a Venturi high-frequency ventilator (Bird). Ten healthy mongrel dogs were anesthetized with sodium pentobarbital, catheterized with intrapleural and thermodilution pulmonary artery lines, and subjected to oleic acid-induced pulmonary edema. A mean PEEP of 16 +/- 6 (SD) cm H2O restored venous admixture to baseline in nine animals. Both mean airway pressure (Paw) and mean intrapleural pressure (Ppl) increased significantly with each increment of PEEP during HFV. Approximately 50% of Paw was transmitted to the intrapleural space. Cardiac index (CI) decreased with increments of PEEP in spite of constant transmural central venous and pulmonary capillary wedge pressures, so that oxygen delivery decreased despite increased PaO2. Possible mechanisms of PEEP-induced depression of CI during HFV are discussed. We conclude that both hemodynamic and intrapleural effects of PEEP during HFV are similar to those during conventional mechanical ventilation.

Animals↗
PubMed1985

Large volume crystalloid resuscitation does not increase extravascular lung water.

The purpose of this study was to determine whether Ringer's lactate solution increases extravascular lung water (EVLW) during resuscitation after hemorrhagic shock. Ten sheep anesthetized with thiamylal were bled to a mean arterial pressure (MAP) of 50 mm Hg; further bleeding maintained that pressure for 30 min. Resuscitation fluid consisted of Ringer's lactate solution in volumes necessary to restore and maintain for 1 hr MAP, pulmonary capillary wedge pressure (PCWP), and cardiac index at levels equal to those measured before bleeding. After volume replacement, the colloid oncotic pressure (COP) - PCWP gradient (COP - PCWP) decreased from 12 +/- 3 to 2 +/- 5 mm Hg (P less than 0.001). After volume restoration, COP decreased from 19 +/- 8 mm Hg to 12 +/- 2 mm Hg (P less than 0.001). Despite the large volume of fluid administered, EVLW did not increase. Crystalloid resuscitation does not necessarily increase EVLW despite significant decreases in COP and COP - PCWP gradient.

Animals↗
PubMed1984

Titration of PEEP by the arterial minus end-tidal carbon dioxide gradient.

It was shown in dogs that intrapulmonary physiologic shunt (Qsp/Qt), arterial oxygen tension (PaO2), total static respiratory compliance (CT), oxygen delivery (O2AV), cardiac output (Qt), and arterial minus end-tidal carbon dioxide gradient (PaCO2-PetCO2) undergo statistically significant deterioration when oleic acid is injected into the pulmonary artery. Positive end-expiratory pressure (PEEP) therapy reduced Qsp/Qt and PaCO2-PetCO2 gradient and increased PaO2. The CT did not show any consistent pattern of improvement with the application of PEEP. The Qt and the O2AV progressively decreased as PEEP was increased. The application of additional PEEP beyond that which minimized the PaCO2-PetCO2 gradient produced a statistically significant increase in the PaCO2-PetCO2 gradient, but this was not reflected by concomitant changes in Qsp/Qt or PaO2 in spite of a further decrease in Qt. Thus, the PaCO2-PetCO2 gradient may be a more sensitive indicator of excessive PEEP than is Qst/Qt or PaO2, since it should be smallest when there is maximal recruitment of perfused or functional gas units without overdistention of alveolar areas contributing to dead space. Also, the use of the PaCO2-PetCO2 gradient permits the rapid titration of PEEP without the need for a pulmonary artery catheter.

Animals↗