Biomedical subjects
Publications and source records attributed to D P Lohmann.
During the latter half of the twentieth century, physicians have had the capability to support the circulation with mechanical devices. This article gives an historical overview of those devices. Various devices and their complications are described and evaluated. Patient selection and clinical results also are discussed.
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This article provides a brief overview of the ventricular assist devices (VADs) available for patients with severe ventricular failure. The history of VAD development and clinical results in the adult and pediatric population are reviewed. Because the VAD role is expanding, nursing implications and a critical analysis of the growing economic concerns regarding their use are discussed.
Patient selection is considered one of the most important factors influencing success in bridge to transplant procedures. However, to date it has been difficult to identify predictors of mortality in this population using univariate or multivariate analysis. In 1988, we developed a scoring system using 21 clinical variables that could be calculated rapidly at the bedside while evaluating potential candidates. Points were designated to these variables using a scale of 1 to 3, 1 having the least adverse effect on survival and 3 the most. Patients received a value of 0 for each variable that did not apply. This scoring system was used in a retrospective analysis for 15 bridge to transplant patients. The results showed a significant difference (p < 0.003) between the 8 survivors (mean score, 5.75 +/- 2.19) and the 7 nonsurvivors (mean score, 11.71 +/- 3.45). Since 1989, we have prospectively calculated the scores in an additional 27 patients. Based on the score, all 42 patients were divided into three groups: group I had scores of 1 to 5; group II, 6 to 10; and group III, 11 to 16. The mean score for group I (16 patients) was 3.69 +/- 1.25. All group I patients survived. Group II patients (n = 15) had a mean score of 7.87 +/- 1.36 and a survival rate of 53%. The mean score for group III (n = 11) was 13 +/- 1.73. Thirty-six percent of these patients survived. Comparison of survival and mean scores among the three groups was statistically significant (p < 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)
The clinical and billing records of 250 patients (173 men and 77 women) undergoing isolated coronary artery bypass grafting between 1987 and mid-1990 were retrospectively reviewed to determine charges and clinical results as related to age. Patients were stratified by age into five groups of 50 consecutive patients each: group 1, less than 50 years of age; group 2, 50 to 59 years; group 3, 60 to 69 years; group 4, 70 to 79 years; and group 5, 80 years or older. The groups were compared in regard to perioperative clinical variables, long-term follow-up, and total charges. Group 5 had significantly more postoperative complications than the other four groups (p < 0.05). In addition, length of postoperative hospitalization was significantly longer in group 5 compared with groups 1, 2, and 3 (p < 0.05), and operative mortality in group 5 (20%) was significantly higher than that in the other four groups. The mean total charges for group 5 were $73,399, which was significantly higher than the totals in the other four groups (p < 0.05). Actuarial 3-year survival for the hospital survivors was 87%, 89%, 78%, 82%, and 60% for groups 1, 2, 3, 4, and 5, respectively (p < 0.001). Postoperative performance as measured by the Karnofsky scale was significantly lower in group 5 than in groups 1 and 2 (p < 0.05). These data support the premise that elderly patients undergoing coronary artery bypass grafting have more complications, longer hospitalizations, and higher operative mortality than younger patients.(ABSTRACT TRUNCATED AT 250 WORDS)
Conventional therapy in the management of adult respiratory distress syndrome is often associated with an increased mortality rate. Several methods to improve survival in patients with severe respiratory insufficiency are under evaluation. One recently developed method of treatment is an implantable intravascular oxygenator, which provides supplemental gas exchange for failing lungs. This device can provide temporary ventilatory support in patients with acute, potentially reversible respiratory insufficiency. Reduction in ventilator settings such as airway pressure, oxygen concentration, positive end-expiratory pressure and minute volume can be achieved, decreasing the likelihood of oxygen toxicity and barotrauma. Success of the intravascular oxygenator in adult respiratory distress syndrome is dependent in part on critical care staff expertise. Therefore, a thorough understanding of the operation of this device and its role in acute respiratory failure is necessary for optimal care.
In this communication we describe a technique to change paracorporeal ventricular assist devices after the development of mechanical complications. This procedure is technically simple and in our experience does not require a sternotomy or cardiopulmonary bypass. Paracorporeal ventricular assist devices can be safely changed allowing continued support and survival.
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Patients bridged to transplantation with ventricular assist devices (VADs) often require prolonged support. To reduce complications associated with bed rest, the authors developed a program to mobilize patients with VADs. Between August 1986 and May 1992, 25 men and 7 women aged 12-65 years (mean: 42.4 years) were bridged for possible transplantation. The 32 patients were supported with either a Novacor (n = 9) or a Thoratec (n = 23) VAD. Thirty-one patients were turned within 2-12 hr of VAD insertion and received range of motion therapy. Twenty-six patients sat in a chair 2-16 days (mean: 5 days) after VAD insertion. Twenty-one patients used a stationary bicycle, and 23 patients were ambulatory 3-57 days (mean: 11 days) after VAD insertion. Two patients were transplanted within 72 hr of device insertion. Twenty-one of the 23 ambulatory patients were successfully transplanted or weaned from the VAD and discharged from the hospital. Two ambulatory patients who were difficult to rehabilitate (ambulatory 22 and 57 days, respectively, after VAD insertion) died before transplantation. In conclusion, VAD patients should be mobilized early because the VAD can improve exercise capability and survival rate.
Since 1985, 59 United Network for Organ Sharing status I patients have been considered for heart transplantation. Thirty-four patients were supported with drugs and/or intraaortic balloon pump (IABP) (group I). Twenty-five patients were supported with ventricular assist devices (VADs, group II). Forty percent of the patients in each group died before transplantation. Of the 20 group I patients who underwent transplantation, all received inotropic drugs, and five also required IABPs. All 14 group II patients who underwent transplantation were bridged with VADs. No difference was found in age, sex, or cause of disease between the groups. Complications after transplantation were more common in group I. Fourteen group I patients (70%) and 14 group II patients (100%) were discharged from the hospital (p = 0.03). One year after transplantation, mean left ventricular ejection fraction by cardiac catheterization was 53% in group I (12 patients) and 72% in group II (11 patients; p = 0.0008). Although VAD support does not insure transplantation, it strongly favors transplantation survival in status I patients. These data further suggest an advantage of VAD support for long-term survival.
The effect of ventricular arrhythmias (VA) on survival was retrospectively reviewed in 41 patients (33 men, 8 women) who were supported with Thoratec ventricular assist devices (VAD [Thoratec Medical Inc., Berkeley, CA]) (17 left, 9 right, and 15 biventricular). Ages ranged from 15 to 71 years (mean, 56 years), and duration of support was 0.1-17 days (mean, 4.7 days). There was no significant difference in age, gender, or type of support between survivors and nonsurvivors, and no correlation between the type of support and incidence of VA. Only two patients (both on left ventricular assist devices [LVAD]) died as a direct result of VA. There was no significant difference in the occurrence of VA before or during VAD support between survivors and nonsurvivors. These data show that evidence of VA is not a predictor of survival in patients in whom myocardial recovery is expected.
In a retrospective study of 28 patients (23 men, 5 women) supported with ventricular assist devices greater than 3 days, the effect of LV cannulation versus LA cannulation on device performance was compared. Patients ranged in age from 12 to 67 years (mean 46 years) and were supported for 3-81 days (mean 15 years). Fifteen patients were supported with left VADs (6 LV and 9 LA), and 13 patients were supported with BVADs (5 LV and 8 LA). The mode of operation 91% of the time was the fill-to-empty mode. Ten data points were taken for each patient. LV cannulation results in higher VAD flow index at decreased preload, lower VAD systolic and vacuum pressures, and shorter diastolic durations. Eleven of the 28 patients survived. Although survival was greater in patients with LV cannulation, survival was more dependent upon reversibility of myocardial damage, eligibility for transplantation, or the development of complications. These data indicate that LV cannulation provides better VAD performance than LA cannulation in the fill-to-empty mode.
BACKGROUND: The current health care environment mandates closer scrutiny of health care dollar allocation. To better understand the distribution of heart transplantation costs, we reviewed hospital and physician billing of patients who underwent orthotopic heart transplantation between August 1988 and September 1993. METHODS: This study is a retrospective review of 107 consecutive cases. Charges and clinical results of United Network for Organ Sharing status 1 patients (n = 46), including 17 bridge to transplantation patients, were compared with those of United Network for Organ Sharing status 2 patients (n = 57). Charges were converted to 1992 dollars. RESULTS: During the first 12 months of the study, 77% of heart transplantations were performed in United Network for Organ Sharing status 2 patients, whereas over the last 12-month period, 25% of the transplantations were performed in status 2 patients. No significant differences were found in age, gender, type of cardiomyopathy, or survival between the status 1 and status 2 groups. The length of hospitalization for the status 1 group ranged from 8 to 138 days (mean 49 days) as opposed to 5 to 82 days (mean 17.5 days) for the status 2 group (p < 0.0001). Pretransplantation hospital charges were significantly higher for the status 1 group ($47,917 to $341,215, mean $109,116) when compared with status 2 ($0 to $10,035, mean $250) (p < 0.0001). No significant difference was found in posttransplantation hospital charges between status 1 ($47,917 to $210,027, mean $95,379) and status 2 patients ($48,093 to $380,745, mean $102,265). Total charges were significantly higher (p < 0.0001) for the status 1 group ($89,910 to $512,331, mean $239,375) when compared with the status 2 group ($63,885 to $455,680, mean $128,594). Total transplantation charges for the study period were $18,341,108. This amount could have paid for 77 status 1 transplantations or 143 status 2 transplantations. CONCLUSIONS: If current trends continue and the donor pool remains the same, most transplant recipients will be status 1, resulting in a comparable number of transplantations performed at twice the charges.
OBJECTIVE: To determine morbidity and mortality rates in octogenarians undergoing cardiac surgical repairs and to compare these results with a similar group of younger patients. DESIGN: Retrospective, two-group. SETTING: Midwestern university medical center. SUBJECTS: Group I consisted of 235 male and female patients who were all less than 80 years of age. Group II consisted of 235 male and female patients who were 80 years of age or older. Both groups underwent similar cardiac surgical procedures. OUTCOME MEASURES: Development of postoperative complications, length of hospitalization, and mortality. RESULTS: When comparing octogenarians with younger patients, octogenarians developed significantly more postoperative complications with higher operative mortality. In addition, octogenarians were hospitalized significantly longer than the younger group. CONCLUSION: These findings suggest that age is a major risk factor influencing outcome after surgery. However, by incorporating nursing interventions with geriatric concepts, those postoperative complications that are common in octogenarians may be more effectively treated and possibly prevented. With sensitive and knowledge-based care, most older patients can anticipate good recovery after cardiac surgery.