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Andre R Campbell

Publications and source records attributed to Andre R Campbell.

8 recordsLinked to original sources
PubMed2006

Effects of tidal volume on work of breathing during lung-protective ventilation in patients with acute lung injury and acute respiratory distress syndrome.

OBJECTIVE: To assess the effects of step-changes in tidal volume on work of breathing during lung-protective ventilation in patients with acute lung injury (ALI) or the acute respiratory distress syndrome (ARDS). DESIGN: Prospective, nonconsecutive patients with ALI/ARDS. SETTING: Adult surgical, trauma, and medical intensive care units at a major inner-city, university-affiliated hospital. PATIENTS: Ten patients with ALI/ARDS managed clinically with lung-protective ventilation. INTERVENTIONS: Five patients were ventilated at a progressively smaller tidal volume in 1 mL/kg steps between 8 and 5 mL/kg; five other patients were ventilated at a progressively larger tidal volume from 5 to 8 mL/kg. The volume mode was used with a flow rate of 75 L/min. Minute ventilation was maintained constant at each tidal volume setting. Afterward, patients were placed on continuous positive airway pressure for 1-2 mins to measure their spontaneous tidal volume. MEASUREMENTS AND MAIN RESULTS: Work of breathing and other variables were measured with a pulmonary mechanics monitor (Bicore CP-100). Work of breathing progressively increased (0.86 +/- 0.32, 1.05 +/- 0.40, 1.22 +/- 0.36, and 1.57 +/- 0.43 J/L) at a tidal volume of 8, 7, 6, and 5 mL/kg, respectively. In nine of ten patients there was a strong negative correlation between work of breathing and the ventilator-to-patient tidal volume difference (R = -.75 to -.998). CONCLUSIONS: : The ventilator-delivered tidal volume exerts an independent influence on work of breathing during lung-protective ventilation in patients with ALI/ARDS. Patient work of breathing is inversely related to the difference between the ventilator-delivered tidal volume and patient-generated tidal volume during a brief trial of unassisted breathing.

Acute Disease↗
PubMed2005

Clinical implementation of the ARDS network protocol is associated with reduced hospital mortality compared with historical controls.

OBJECTIVE: To assess the impact of implementing a low tidal volume ventilation strategy on hospital mortality for patients with acute lung injury or acute respiratory distress syndrome. DESIGN: Retrospective, uncontrolled study. SETTING: Adult medical-surgical and trauma intensive care units at a major inner city, university-affiliated hospital. PATIENTS: A total of 292 patients with acute lung injury or acute respiratory distress syndrome. INTERVENTIONS: Between the years 2000 and 2003, 200 prospectively identified patients with acute lung injury/acute respiratory distress syndrome were managed by the ARDS Network low tidal volume protocol. A historical control group of 92 acute respiratory distress syndrome patients managed by routine practice from 1998 to 1999 was used for comparison. MEASUREMENTS AND MAIN RESULTS: Patients managed with the ARDS Network protocol had a lower hospital mortality compared with historical controls (32% vs. 51%, respectively; p = .004). Multivariate logistic regression estimated an odds ratio of 0.32 (95% CI, 0.17-0.59; p = .0003) for mortality risk with use of the ARDS Network protocol. Protocol-managed patients had a lower tidal volume (6.2 +/- 1.1 vs. 9.8 +/- 1.5 mL/kg; p < .0001) and plateau pressure (27.5 +/- 6.4 vs. 33.8 +/- 8.9 cm H2O; p < .0001) than historical controls. CONCLUSION: Adoption of the ARDS Network protocol for routine ventilator management of acute lung injury/acute respiratory distress syndrome patients was associated with a lower mortality compared with recent historical controls.

APACHE↗
PubMed2005

Work of breathing during lung-protective ventilation in patients with acute lung injury and acute respiratory distress syndrome: a comparison between volume and pressure-regulated breathing modes.

BACKGROUND: Pressure-control ventilation (PCV) and pressure-regulated volume-control (PRVC) ventilation are used during lung-protective ventilation because the high, variable, peak inspiratory flow rate (V (I)) may reduce patient work of breathing (WOB) more than the fixed V (I) of volume-control ventilation (VCV). Patient-triggered breaths during PCV and PRVC may result in excessive tidal volume (V(T)) delivery unless the inspiratory pressure is reduced, which in turn may decrease the peak V (I). We tested whether PCV and PRVC reduce WOB better than VCV with a high, fixed peak V (I) (75 L/min) while also maintaining a low V(T) target. METHODS: Fourteen nonconsecutive patients with acute lung injury or acute respiratory distress syndrome were studied prospectively, using a random presentation of ventilator modes in a crossover, repeated-measures design. A target V(T) of 6.4 + 0.5 mL/kg was set during VCV and PRVC. During PCV the inspiratory pressure was set to achieve the same V(T). WOB and other variables were measured with a pulmonary mechanics monitor (Bicore CP-100). RESULTS: There was a nonsignificant trend toward higher WOB (in J/L) during PCV (1.27 + 0.58 J/L) and PRVC (1.35 + 0.60 J/L), compared to VCV (1.09 + 0.59 J/L). While mean V(T) was not statistically different between modes, in 40% of patients, V(T) markedly exceeded the lung-protective ventilation target during PRVC and PCV. CONCLUSIONS: During lung-protective ventilation, PCV and PRVC offer no advantage in reducing WOB, compared to VCV with a high flow rate, and in some patients did not allow control of V(T) to be as precise.

Adult↗
PubMed2004

Acute respiratory distress syndrome criteria in trauma patients: why the definitions do not work.

BACKGROUND: The international consensus definitions for acute respiratory distress syndrome (ARDS) have formed the basis for recruitment into randomized, controlled trials and, more recently, standardized the protocols for ventilatory treatment of acute lung injury. Although possibly appropriate for sepsis-induced ARDS, these criteria may not be appropriate for posttraumatic ARDS if the disease patterns are widely divergent. This study tests the hypothesis that standard ARDS criteria applied to the trauma population will capture widely disparate forms of acute lung injury and are too nonspecific to identify a population at risk for prolonged respiratory failure and associated complications. METHODS: Patients with and Injury Severity Score > or = 16 ventilated for > 12 hours were prospectively enrolled. Clinical data, including elements of cardiovascular, renal, hepatic, hematologic, neurologic, and pulmonary function, were collected daily. Two hundred fifty-four patients were enrolled over a 36-month period, of whom 70 met the consensus definitions of ARDS. Patients from whom support was withdrawn within 48 hours were excluded. The remaining 61 patients were stratified into two groups on the basis of intubation (n = 12) days. RESULTS: There was considerable disparity in severity and clinical course. A mild, limited form of ARDS was characterized by earlier onset (group 1, 2 days; group 2, 4 days; p = 0.002), fewer intubation days (7 days vs. 28 days; p < 0.001), and less severe derangements in lung mechanics. A significant difference between the two groups was also seen in systemic inflammatory response syndrome score, incidence of sepsis, and incidence of multiple organ failure. CONCLUSION: The criteria for ARDS, when applied to the trauma population, capture a widely disparate group and has poor specificity for identifying patients at risk. Recruitment of trauma patients for ARDS studies or preemptive ventilatory management based solely on these criteria may be ill-advised.

Adult↗
PubMed2003

Discussion of medical errors in morbidity and mortality conferences.

CONTEXT: Morbidity and mortality conferences in residency programs are intended to discuss adverse events and errors with a goal to improve patient care. Little is known about whether residency training programs are accomplishing this goal. OBJECTIVE: To determine the frequency at which morbidity and mortality conference case presentations include adverse events and errors and whether the errors are discussed and attributed to a particular cause. DESIGN, SETTING, AND PARTICIPANTS: Prospective survey conducted by trained physician observers from July 2000 through April 2001 on 332 morbidity and mortality conference case presentations and discussions in internal medicine (n = 100) and surgery (n = 232) at 4 US academic hospitals. MAIN OUTCOME MEASURES: Frequencies of presentation of adverse events and errors, discussion of errors, and attribution of errors. RESULTS: In internal medicine morbidity and mortality conferences, case presentations and discussions were 3 times longer than in surgery conferences (34.1 minutes vs 11.7 minutes; P =.001), more time was spent listening to invited speakers (43.1% vs 0%; P<.001), and less time was spent in audience discussion (15.2% vs 36.6%; P<.001). Fewer internal medicine case presentations included adverse events (37 [37%] vs 166 surgery case presentations [72%]; P<.001) or errors causing an adverse event (18 [18%] vs 98 [42%], respectively; P =.001). When an error caused an adverse event, the error was discussed as an error less often in internal medicine (10 errors [48%] vs 85 errors in surgery [77%]; P =.02). Errors were attributed to a particular cause less often in medicine than in surgery conferences (8 [38%] of 21 medicine errors vs 88 [79%] of 112 surgery errors; P<.001). In discussions of cases with errors, conference leaders in both internal medicine and surgery infrequently used explicit language to signal that an error was being discussed and infrequently acknowledged having made an error. CONCLUSIONS: Our findings call into question whether adverse events and errors are routinely discussed in internal medicine training programs. Although adverse events and errors were discussed frequently in surgery cases, teachers in both surgery and internal medicine missed opportunities to model recognition of error and to use explicit language in error discussion by acknowledging their personal experiences with error.

General Surgery↗
PubMed2003

The development of acute lung injury is associated with worse neurologic outcome in patients with severe traumatic brain injury.

OBJECTIVE: The purpose of this study was to determine the incidence of acute lung injury (ALI) in trauma patients with severe traumatic brain injury (TBI), to evaluate the impact of ALI on mortality and neurologic outcome after severe traumatic brain injury (TBI), and to identify whether the development of ALI correlates with the severity of TBI. METHODS: Clinical data were collected prospectively over a 4-year period in a Level I trauma center. Patients included in the study met the following criteria: mechanical ventilation > 24 hours, head Abbreviated Injury Scale score >or= 3, no other body region Abbreviated Injury Scale score >or= 3, and age between 18 and 54 years. ALI was defined using international consensus criteria. Glasgow Outcome Scale scores were assessed at 3 and 12 months. Bivariate comparisons were made between ALI and non-ALI groups. Multivariate analysis with stepwise logistical regression was used to assess independent factors on mortality. The patient's admission head computed tomographic (CT) scan was graded using the Marshall system, and the presence and size of specific intracranial abnormality was noted. Glasgow Coma Scale (GCS) score, Marshall CT scan score, and intracranial abnormality were correlated with the development of ALI. RESULTS: One hundred thirty-seven patients with isolated head trauma were enrolled in the study over a 4-year period. Thirty-one percent of patients with severe TBI developed ALI. Head trauma patients with ALI had a significantly higher ISS, a greater number of days on the ventilator, and a worse neurologic outcome for those who survived their hospitalization. Mortality was 38% in the ALI group and 15% in the non-ALI group (p = 0.004). Only 3 of 16 (19%) of the deaths within the ALI group were directly related to ALI. By multivariate analysis, only the presence of ALI, older age, and lower initial GCS score were associated with higher mortality. There was no association between ISS, the presence of arterial hypotension (arterial systolic pressure < 90 mm Hg) at admission to the hospital, or the amount of blood transfused and mortality. No correlation was found between the severity of head injury (GCS score, Marshall score, or intracranial abnormality) and development of ALI. CONCLUSION: The development of ALI is a critical independent factor affecting mortality in patients suffering traumatic brain injury and is associated with a worse long-term neurologic outcome in survivors. The risk of developing ALI is not associated with specific anatomic lesions diagnosed by cranial CT scanning.

Abbreviated Injury Scale↗
PubMed2002

The effects of tidal volume demand on work of breathing during simulated lung-protective ventilation.

BACKGROUND: Lung-protective ventilation (LPV) can result in a ventilator tidal volume (V(T)) below patient V(T) demand, which may elevate work of breathing (WOB). Increasing the ventilator inspiratory flow may not sufficiently reduce WOB, because the patient's flow-time requirements may exceed the ventilator's flow-time delivery pattern. We investigated (1) the effects of V(T) demand on WOB during LPV and (2) which ventilator pattern best reduced WOB while achieving LPV goals. METHODS: A standard WOB lung model simulated assisted breathing. Using 3 ventilators (Hamilton Veolar, Hamilton Galileo, and Dräger Evita 2 dura), we tested volume-control ventilation with a constant flow pattern (VCV-CF), volume-control ventilation with a decelerating flow (VCV-DF), and pressure-control ventilation (PCV). Simulated V(T) demand was increased from 50-125% of the ventilator-delivered V(T) (400 mL) as ventilator inspiratory time (T(I)) was decreased (0.95, 0.80, 0.65, and 0.45 s) relative to simulated T(I) (0.8 s). WOB was measured with a pulmonary mechanics monitor. RESULTS: During VCV-CF and VCV-DF, a V(T) demand of > or = 100% drastically increased WOB, attributable to imposed WOB from the inspiratory valve. Increasing inspiratory flow by using the decelerating flow pattern and/or decreasing T(I) reduced WOB, but generally not to normal levels. "Double-triggered" breaths, with excessive V(T) delivery, often occurred when ventilator T(I) was well below simulated T(I). PCV was most effective in reducing WOB, but V(T) delivery exceeded the LPV target unless T(I) was reduced. CONCLUSIONS: Given our dual goals of reducing both WOB and V(T) during LPV, VCV-DF with relatively brief T(I) appeared to be the best option, followed by PCV with a relatively brief T(I).

Computer Simulation↗