Showing papers by "Robert H. Bartlett published in 1995"
TL;DR: Preliminary data suggest that partial liquid ventilation can be safely used in patients with severe respiratory failure and may improve lung function.
198 citations
TL;DR: Gas exchange, pulmonary function, and lung histology during perfluorocarbon liquid ventilation (LV) when compared with gas ventilation (GV) in the setting of severe respiratory failure was evaluated in premature animals with surfactant deficiency and a marked reduction in alveolar hemorrhage, lung fluid accumulation, and inflammatory infiltration was demonstrated.
Abstract: ObjectiveThe authors evaluated gas exchange, pulmonary function, and lung histology during perfluorocarbon liquid ventilation (LV) when compared with gas ventilation (GV) in the setting of severe respiratory failure.BackgroundThe efficacy of LV in the setting of respiratory failure has been evaluate
148 citations
TL;DR: In this paper, the authors evaluated gas exchange, pulmonary function, and lung histology during gas ventilation of the perfluorocarbon-filled lung compared with gas ventilation in severe respiratory failure.
141 citations
TL;DR: Bronchoscopy has been incorporated as a useful adjunct to increase the safety and effectiveness of percutaneous endoscopic tracheostomy (PET), but insertion of the bronchoscope into the airway potentially leads to hypoventilation and hypercarbia during the procedure.
91 citations
TL;DR: Perfluorocarbon liquid ventilation has been shown to have advantages over conventional gas ventilation in premature newborn and lung-injured animals and can be performed successfully utilizing this simple adaptation of an extracorporeal life-support circuit.
Abstract: OBJECTIVE Perfluorocarbon liquid ventilation has been shown to have advantages over conventional gas ventilation in premature newborn and lung-injured animals. To simplify the process of liquid ventilation, we adapted an extra-corporeal life-support circuit as a time-cycled, volume-limited liquid ventilator. DESIGN Laboratory study that involved sequential application of gas and liquid ventilation in normal cats and in lung-injured sheep. SETTING A research laboratory at a university medical center. SUBJECTS Eight normal cats weighing 2.7 to 3.8 kg (mean 3.1 +/- 0.5), and four lung-injured young sheep weighing 10.4 to 22.5 kg (mean 15.9 +/- 5.0). INTERVENTIONS Normal cats were supported with traditional gas ventilation for 1 hr (respiratory rate 20 breaths/min, peak inspiratory pressure 12 cm H2O, positive end-expiratory pressure 4 cm H2O, and FIO2 1.0). The lungs were then filled with perfluorocarbon (30 mL/kg) and tidal volume liquid ventilation was instituted, utilizing a newly developed liquid ventilation device. Liquid ventilatory settings were 4 secs for inspiration time, 8 secs for expiration time, 5 breaths/min for respiratory rate, and 15 to 20 mL/kg for tidal volume. Liquid ventilation utilizing this device was also applied to sheep after induction of severe lung injury by right atrial injection of 0.07 mL/kg of oleic acid, followed by saline pulmonary lavage. Extracorporeal life support was instituted to provide a stable model of lung injury. For the first 30 mins of extracorporeal support, all animals were ventilated with gas. Animals were then ventilated with 15 mL/kg of perfluorocarbon over the ensuing 2.5 hrs. MEASUREMENTS AND MAIN RESULTS In normal cats, mean PaO2 values after 1 hr of liquid or gas ventilation were 275 +/- 90 (SD) torr (36.7 +/- 10.4 kPa) in the liquid-ventilated animals and 332 +/- 78 torr (44.3 +/- 10.4 kPa) in the gas-ventilated animals (NS). Mean PaCO2 values were 40.5 +/- 5.7 torr (5.39 +/- 0.31 kPa) in the liquid-ventilated animals and 37.6 +/- 2.3 torr (5.01 +/- 0.31 kPa) in the gas-ventilated animals (NS). Mean arterial pH values were 7.35 +/- 0.07 in the liquid-ventilated animals and 7.34 +/- 0.04 in the gas-ventilated animals (NS). No significant changes in heart rate, mean arterial pressure, lung compliance, or right atrial venous oxygen saturation were observed during liquid ventilation when compared with gas ventilation. In the lung-injured sheep, an increase in physiologic shunt from 15 +/- 7% to 66 +/- 9% was observed with induction of lung injury during gas ventilation. Liquid ventilation resulted in a significant reduction in physiologic shunt to 31 +/- 10% (p < .001). In addition, the extracorporeal blood flow rate required to maintain the PaO2 in the 50 to 80 torr (6.7 to 10.7 kPa) range was substantially and significantly (p < .001) lower during liquid ventilation than during gas ventilation (liquid ventilation 15 +/- 5 vs. gas ventilation 87 +/- 15 mL/min/kg). CONCLUSIONS Liquid ventilation can be performed successfully utilizing this simple adaptation of an extracorporeal life-support circuit. This modification to an existing extracorporeal circuit may allow other centers to apply this new investigational method of ventilation in the laboratory or clinical setting.
64 citations
TL;DR: Survival is not significantly greater with VV ECLS when patients are matched for degree of respiratory and hemodynamic failure, and there is no identified difference in the incidence of intracranial hemorrhage.
Abstract: It has been suggested that venovenous (VV) extracorporeal life support (ECLS) confers a survival advantage over venoarterial (VA) ECLS. These results have been confounded by differences in patient populations. In this study, a matched pairs comparison of survival and complication rates in neonatal respiratory failure patients managed with VA or VV ECLS was performed. Retrospective matching of 643 VA and VV patient pairs from the Extracorporeal Life Support Organization Registry was performed. Pairs were matched by same year, same diagnosis, gestational age +/- 1 week, birth weight +/- 0.3 kg, and oxygenation index +/- 5. Further matching for hemodynamic status was possible for 272 pairs and included pre ECLS CPR, use of epinephrine, and arterial pH +/- 0.1. Statistical significance was defined for outcome and selected complication rates using McNemar's chi-square analysis with correction for multiple comparisons. A survival advantage for VV was significant when matching for respiratory failure (83.8% VA versus 91.5% VV), but was not significant when matching for hemodynamic failure (90.4% VA versus 94.5% VV). In the latter match, hemolysis (10.7% VA versus 23.5% VV) and cannula kinking (0.4% VA versus 10.6% VV) were more common with VV ECLS. The incidence of intracranial hemorrhage did not significantly differ between groups (6.3% VA versus 7.4% VV). Survival is not significantly greater with VV ECLS when patients are matched for degree of respiratory and hemodynamic failure. Hemolysis and cannula kinking are more common with VV ECLS. There is no identified difference in the incidence of intracranial hemorrhage.
30 citations
11 citations
TL;DR: The initiation of ECMO with a normocalcemic prime results in a minimal change in patient ionized calcium and resolution of the hypotension previously observed, and there was poor correlation between ionization calcium, total calcium, and other indirect measures of ionizedcium.
Abstract: The authors' objectives in this investigation were: 1) to prospectively determine whether a normocalcemic priming solution would result in elimination of hypocalcemia after the initiation of extracorporeal membrane oxygenation (ECMO); 2) to investigate whether normocalcemia would result in improvements in the patient's hemodynamics during the initiation of ECMO; and 3) to further define the relationship between ionized calcium measurements and total calcium, serum total protein, serum albumin, and total magnesium. This was a prospective study done in our neonatal intensive care unit, and included nine neonatal patients placed on ECMO for cardiopulmonary support. The bypass circuit was primed in the standardized manner with 100 mg calcium chloride. Circuit ionized calcium measurements were performed, and additional calcium chloride was added to normalize the ionized calcium in the priming solution. Ionized calcium was measured from the circuit and the patient before the initiation of ECMO, and then again from the patient 5, 10, 15, 30, 60, 120, and 240 minutes after the initiation of ECMO. The patients' mean arterial pressure was measured simultaneously with each ionized calcium measurement. Ionized calcium, serum total calcium, total protein, serum albumin, and total magnesium were measured from blood samples simultaneously collected four times daily. There was no significant change in the ionized calcium measured in the patients after the initiation of ECMO. There was, however, a significant increase in blood pressure 5 min after the initiation of ECMO (62 +/- 7 mmHg vs 53 +/- 6 mmHg, p = 0.01). Thereafter, there was no difference in blood pressure measured when compared with pre ECMO values. A poor correlation was demonstrated between ionized calcium and total calcium (r2 = 0.35), serum total protein (r2 = 0.26), serum albumin (r2 = 0.27), and total magnesium (r2 = 0.05). On the basis of the authors' data, the initiation of ECMO with a normocalcemic prime results in a minimal change in patient ionized calcium and resolution of the hypotension previously observed. In addition, there was poor correction between ionized calcium, total calcium, and other indirect measures of ionized calcium. Ionized calcium measurements are critical for patient hemodynamic stability before bypass and should be normalized in both the patient and priming solution before the initiation of bypass.
11 citations
TL;DR: Correlational analyses revealed that length of treatment for ECMO but not CV infants significantly predicted developmental delay and maternal distress, and for CV mothers, maternal distress was associated with the perception of delayed language.
Abstract: Summary Neurodevelopmental outcome and concurrent maternal distress were examined for infants who suffered persistent pulmonary hypertension at birth and were treated with either extracorporeal membrane oxygenation (ECMO) (n= 19) or conventional ventilation (CV) (n= 15). Mothers were asked to complete inventories assessing their infant's (mean age 8.74 months) developmental growth as well as their own psychological health. Relevant sociodemographic and treatment parameters were also entered into the analysis. The results indicated that ECMO and CV infants did not differ on developmental indices and impairment rates were 15–23% respectively, similar to previous reports, in addition, ECMO and CV mothers did not differ in their reports of psychological distress. Correlational analyses revealed that length of treatment for ECMO but not CV infants significantly predicted developmental delay and maternal distress. For CV mothers, maternal distress was associated with the perception of delayed language. The results are discussed in terms of the limited morbidity associated with ECMO and CV interventions and the possible role of a ‘vulnerable child syndrome’ in understanding the maternal-infant relationship following ECMO therapy.
9 citations
TL;DR: "Deing a medical student, Alice perceived the hospi-*-* tal as a place of wonder and armed with 2 years worth of basic facts, she now sought to acquire that knowledge in this Wonderful Place.
4 citations
TL;DR: Using an algebraic solution, the authors developed an equation to calculate true patient mixed venous oxygen saturation during ECLS, which will facilitate optimal management of oxygen kinetics in patients during venovenous extracorporeal support.
Abstract: The ability to monitor the match between systemic oxygen delivery and consumption using mixed venous oxygen saturation is an important component of management of critically ill patients. Mixed venous oxygen saturation is a particularly useful parameter in circumstances where systemic oxygen delivery is significantly compromised, such as the acute respiratory distress syndrome. With the advent of venovenous extracorporeal life support (ECLS) in the treatment of this condition, however, accurate measurement of true mixed venous oxygen saturation has not been available, because of this artificial elevation of venous oxygen content. Using an algebraic solution, the authors developed an equation to calculate true patient mixed venous oxgen saturation during ECLS. This is accomplished using readily obtainable data such as cardiac output, ECLS flow, ECLS circuit pre and post oxygenator blood oxygen content, pulmonary arterial oxygen saturation, and patient hemoglobin. The formula has been used in an in vitro model, simulating venovenous ECLS and native venous saturation ranging from 20-72%, with a resulting correlation coefficient between calculated and measured saturation of 0.983 and a gamma intercept of 0.7. Using this new mathematical model, previously unobtainable information about the match of oxygen delivery and consumption in venovenous ECLS is now available. This information will facilitate optimal management of oxygen kinetics in patients during venovenous extracorporeal support.