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Keywords:

  • Critical pathway;
  • donor management

Abstract

  1. Top of page
  2. Abstract
  3. Introduction
  4. Materials and Methods
  5. Results
  6. Discussion
  7. References

The organ shortage has resulted in increasing recipient waiting lists and waiting-list deaths. The increased use of expanded donors has been associated with increased discarding of procured organs because of poor organ function. A structured donor management algorithm or critical pathway was tested to determine its effect on the donor management and procurement process. A pilot study examined donors from 88 critical care units in 10 organ procurement organizations managed under the critical pathway and compared them to retrospective data collected at those same pilot sites. The total number of organs both procured and transplanted per 100 donors was significantly greater (p < 0.01) in the critical pathway group when compared to the control group. There was no significant difference in 1-year graft survival for any of the organs recovered, and no significant difference in the rate of delayed graft function in the kidneys transplanted. Use of a structured donor management algorithm results in significant increases in organs procured and organs transplanted without any reduction in the quality of the organs being transplanted.


Introduction

  1. Top of page
  2. Abstract
  3. Introduction
  4. Materials and Methods
  5. Results
  6. Discussion
  7. References

The shortage of organs for transplant has reached crisis proportions. As of 30 September 2001, there were more than 78 000 Americans waiting for an organ transplant – a number that is growing each year (see Figure 1). Despite numerous local, national, and federal initiatives to increase the number of cadaveric organ donors in order to meet the growing demand, this number has remained relatively static, rising from 5358 in 1995 to only 5984 in 2000. This growing disparity results in thousands of deaths each year that might have been prevented had enough organs been available. The modest gain in the number of cadaver donors has been primarily due to increases in older donors. Donors 50 years of age or greater increased 42.9% and donors under age 50 increased only 1.6% during the same time-frame. Compounding the problem of the lack of donors is a decline of 3% over the last 6 years in the number of organs procured per donor.

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Figure 1. Total donors and organs recovered and waiting-list registrations: 1991–2000.

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The reliance on older, as well as other forms of ‘expanded’ donors has been associated with an increase in discarded organs from 15% in 1990 to 20.6% in 1999 (1). Over the past 10 years, 7662 kidneys, 2509 livers, 378 hearts, and 494 lungs were procured but not transplanted, thus demonstrating the large number of patients who might have benefited from these discarded organs had they been suitable for transplantation. The reasons reported most often for not transplanting procured organs, or for not procuring organs from consented donors, are poor organ function and/or biopsy findings (1). Recently, both the technique (2) and the prognostic significance of certain pathological findings with kidney biopsies (3,4) have been reassessed, leaving poor organ function as the dominant reason for not transplanting consented organs. In fact, during the years 1995–2000, the number of consented kidneys that were not transplanted due to poor organ function was 1581 (2.4%) and the number of hearts was 5099 (17.2%).

The profound pathophysiological devastation associated with the sequelae of brain death (5,6) is of such magnitude that, in spite of conventional cardiopulmonary support, as many as 25% of potential donors may have a loss of perfusion to their organs, making them unsuitable for transplant before the organs can be retrieved (7). On the other hand, it has been shown that aggressive donor management, which may include pulmonary artery catheter monitoring and a combination of pharmacologic agents, can transform a significant number of donors with initially unacceptable cardiac function into acceptable and successful heart donors (8). All organs may benefit from aggressive management, and improved cardiac function can be expected to lead to an improvement in the function of all organs. Current evidence regarding the evaluation and management of potential cardiac donors led to the recommendation made at the Crystal City Consensus Conference (2001), that organ procurement organizations should use a standard protocol for donor management which includes increased application of pulmonary arterial catheterization (9). The need for this type of uniform, aggressive support of brain-dead potential organ donors to prevent cardiovascular collapse, inadequate organ perfusion, and organ loss has led to the further modification of a donor management critical pathway or algorithm.

Developed by the transplant community, the Critical Pathway for the Organ Donor© was established to facilitate the management and delivery of quality care in an environment where managed care increasingly requires a constraint on resources. Although critical pathways have been found in the literature since 1973, it was not until the 1990s that there was extensive research and publication regarding their contributions to the goals of cost containment and improvement in the delivery of healthcare.

The Critical Pathway for the Organ Donor© (Appendix A) has five distinct, but often overlapping phases: Phase I, Donor Referral; Phase II, Declaration of Brain Death and Consent; Phase III, Donor Evaluation; Phase IV, Donor Management; and Phase V, Organ Recovery (6). Each phase has five subsections that the ICU staff and/or the organ procurement coordinator can use as a guide for thoroughness of evaluation and management. These five subsections are: General Management; Laboratory and diagnostic Tests; Respiratory Therapy; Treatments; Intravenous Fluids and Medications. The Critical Pathway is designed to provide the information necessary to evaluate the functional status of the kidneys, liver, pancreas, heart and lungs and to determine the management steps which need to be taken to improve and optimize the performance of each organ.

We report here on the results of a pilot study of the Critical Pathway, designed to determine whether managing a donor with the Critical Pathway algorithm would result in a more efficient and effective procurement process.

Materials and Methods

  1. Top of page
  2. Abstract
  3. Introduction
  4. Materials and Methods
  5. Results
  6. Discussion
  7. References

Study design

In 1999, ten US organ procurement organizations (OPOs) were identified and subsequently solicited the participation of 88 critical care units to participate in a 4-month prospective study to implement the critical pathway (CP). The critical care units agreed to manage each donor identified under the CP. A 4-month period of time from the previous year (1998) was chosen as a control period (pre-critical pathway or P-CP), in which each donor was managed under traditional protocols.

Organ procurement organizations were chosen for their diversity of population served (2 000 000–11 300 000 population, minority population served 13% – 61%), and geographic location [7 of the 11 United Network for Organ Sharing (UNOS) regions represented]. The locations of the OPOs involved in the study are shown in Figure 2. One site manager was designated at each OPO to coordinate the study activities in those units. The participating critical care units within each of the 10 OPOs were selected based on the average number of donors that the particular unit had over the previous 3-year time-frame in order to ensure representation of all sizes of critical care units. Large metropolitan centers that have a trauma unit traditionally have more organ donors and are accustomed to the donor management process, and therefore selection of critical care units was important. Site managers were asked to include units that had low (0–3 donors per year), moderate (4–5 donors per year) and high (6 or more donors per year) donor potential. The average volume of donors per year at the participating critical care units is shown in Figure 3.

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Figure 2. Critical pathway pilot sites.

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Figure 3. Average volume of donors per year at participating critical care units.

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Critical care staff were trained in the use of the pathway, and OPO staff collected data on each donor. Included in the data collected were: demographic information; time of brain death declaration, consent, and cross-clamp of the aorta in surgery; the number and type of organs consented for recovery; and the number and type of organs actually procured and transplanted. Similar retrospective data were extracted from a chart review of all organ donors from the participating units during the P-CP period.

Statistical methods

The data from the retrospective study were compared with the data from the prospective study. Chi-square tests were performed to detect differences in the demographics between the two cohorts. Analysis of variance, adjusting for OPO, was performed to detect differences in recovery and transplant rates per donor. Also, Kaplan-Meier survival curves were estimated to identify differences in graft survival. All analyses were performed using SAS, version 8.2 (SAS Institute, Cary, NC, USA).

Results

  1. Top of page
  2. Abstract
  3. Introduction
  4. Materials and Methods
  5. Results
  6. Discussion
  7. References

There were 130 total donors in the cohort that was medically managed under the critical pathway (CP), compared with 140 total donors during the control (P-CP) period. The total number of organs recovered and the number of specific organs recovered in the P-CP and CP groups are shown in Table 1. Because there were differences in the total number of donors and because the study was designed to determine if the CP would enhance the effectiveness of the donor management process, organs recovered and transplanted are expressed as the number of organs per 100 donors (Table 1). The CP group had a 10.3% greater number of organs recovered per 100 donors (420.8 vs. 381.4) than were seen in the P-CP group (p < 0.01). When trying to identify whether specific organs were affected by the implementation of the pathway, there was essentially no difference between the CP group and the P-CP group in the number of livers or kidneys recovered per 100 donors (Table 1). However, the numbers of pancreata, hearts, and lungs recovered per 100 donors were greater in the CP group, but were not statistically significant.

Table 1. : Organs recovered
 Pre-Critical PathwayCritical Pathway
OrganNPer 100 donorsNPer 100 donors
Kidney255182.1235180.8
Liver119 85.0116 89.2
Pancreas 33 23.6 53 40.8
Heart 77 55.0 78 60.0
Lung 45 32.1 59 45.4
Intestine  5  3.6  6  4.6
Total534381.4547420.8

The total number of organs transplanted and the number transplanted by organ type in the P-CP and CP groups are shown in Table 2. The CP group had a 3.3% greater total number of organs transplanted and an 11.3% greater number of organs transplanted per 100 donors than that of the P-CP group (p < 0.01). Although the increased number of kidneys transplanted per 100 donors in the CP group was not statistically significant, when the percentage increase (4.8%) is extrapolated to the total number of kidney donors in 1999 (5396), there is a potential increase of 259 kidney transplants. For liver, there was no increase in the number of livers transplanted per 100 donors in the CP group. The percentage increase in pancreata transplanted per 100 donors was 69.4%, which when extrapolated to the total number of pancreas donors in 1999 (1627), would result in an increase of 1129 pancreas transplants. The extrapolated number of increased transplants for hearts is 452 and for lungs, 308. The total extrapolated increase in number of organs transplanted is 2148.

Table 2. : Organs transplanted
 Pre-Critical PathwayCritical Pathway
OrganNPer 100 donorsNPer 100 donors
Kidney224160.0218167.7
Liver109 77.9 99 76.2
Pancreas 26 18.6 41 31.5
Heart 64 45.7 71 54.6
Lung 31 22.1 40 30.8
Intestine  0  0.0  0  0.0
Total454324.3469360.8

There were no significant differences in 1-year graft survival rates between the P-CP and CP groups for any organ. The incidence of delayed graft function for kidneys that were transplanted was 24.0% in the P-CP group, and the incidence of delayed graft function in the CP group was 18.8%. This difference was not statistically significant (p = 0.17). These crude measures help to demonstrate that the quality of the organs transplanted was not different in the two cohorts.

Discussion

  1. Top of page
  2. Abstract
  3. Introduction
  4. Materials and Methods
  5. Results
  6. Discussion
  7. References

This study was designed with the expectation that the critical pathway would result in significant reductions in donor management time and improvements in organ recovery. Although the first expectation was not realized – there was no significant difference in the donor management time – the data analysis showed both a significant increase in the number of organs procured per donor (10.3%) and a significant increase in the number of organs transplanted per donor (11.3%). This result is believed to be due to structured donor evaluation and management that is concerned with the viability and quality of all potentially transplantable organs.

As a result of the Crystal City Consensus Conference recommendation, recent modifications of the original Critical Pathway for the Organ Donor© which include the administration of the Papworth Cocktail, have emphasized improving cardiac function with the expectation that improved cardiac output will result in improved function of the other organs (9). Wheeldon reported on 52 donors whose initial circulatory parameters were below minimal acceptance criteria (8). After inserting a pulmonary catheter, aggressive fluid and pharmacological management resulted in 44 of the 52 donors being suitable for heart procurement and transplantation. Pharmacological management consisted of a methylprednisone bolus and insulin, arginine vasopressin, and triiodothyronine infusions (8). Kron evaluated 14 potential heart donors regarded as marginal because of either echocardiogram wall-motion defects and/or ejection fractions less than or equal to 45% by direct visual inspection of the hearts (10). All 14 hearts were transplanted and all experienced improvement in the ejection fraction with satisfactory function at 30 days. Zaroff reported on nine donors whose initial echocardiogram ejection fraction was less than 50% (11). After an appropriate time-interval after high-dose steroids, ionotrope, and fluid management, a repeat ejection fraction showed improvement in six donors; four of these six became heart donors whose initial cardiac function was satisfactory. The current Critical Pathway calls for an initial echocardiogram, and if the ejection fraction is less than 45%, insertion of a pulmonary artery catheter and aggressive fluid and pharmacological management. The ‘Papworth Cocktail’ found on the pathway, consists of a methylprednisolone bolus and insulin, triiodothyronine, and arginine vasopressin infusions. High-dose methylprednisolone administration to brain-dead donors has been shown to result in improved oxygenation with resultant increased donor lung recovery (12). Triiodothyronine replacement therapy has been shown to reverse myocardial dysfunction in brain-dead donors (13,14) and improve short-term graft survival (14). Since low-dose arginine vasopressin infusions reduce the need for donor ionotropic support, they are associated with satisfactory function of transplanted kidneys, livers, and hearts (15).

The goal of improving cardiac function of all potential donors to the point that they will be considered as heart donors, while idealistic, seems justified. Between 1 January 1998 and 31 December 2000, 17 607 cadaver donors were reported to the Organ Procurement and Transplantation Network (OPTN) database, from which 6893 hearts and 26 885 kidneys were recovered and transplanted. There were 20% more kidneys transplanted from donors whose heart was transplanted compared to donors from whom the heart was not transplanted (91.2% of donors vs. 75.9%, p < 0.001). Of equal importance, kidneys from heart donors had a significantly lower incidence of delayed graft function. In the same cohort of 26 885 kidney transplants, the delayed graft function rate was 18.0% when the heart was transplanted, compared to 24.8% when the heart was not transplanted, p < 0.001. Delayed kidney graft function is associated not only with increased incidences of acute rejection but also with both short-term and long-term, significant decreases in graft survival (16). The data demonstrated a significantly increased 1-year graft survival of kidneys from heart donors (90.9%) when compared to non-heart donors (87.3%), p < 0.001. A report on UNOS data has also indicated that delayed graft function alone adversely affected patient survival significantly (17). In addition, delayed graft function is associated with increased medical and surgical complications, resulting in increased resource utilization and increased length of hospital stay (18).

There is great diversity in organ procurement organization practices and donor potential (19,20). There are wide variations not only between OPOs in the number of donors per million population, but also in the number of kidneys transplanted per million population (19). Certain OPOs have been shown to have a higher incidence of delayed kidney graft function, which may reflect donor selection, donor management, or both (20). There are also substantial OPO variations in cadaveric kidney graft survival, even when the donors are stratified by age or by race (20). It can reasonably be expected that adoption of a standard donor management algorithm may reduce some of these differences in OPOs.

One area where the Critical Pathway algorithm may be particularly useful is in small-volume hospitals that infrequently have cadaveric donor candidates (21). In that setting, the availability of the Critical Pathway may alert critical care personnel to the suitability of a potential donor, and allow those personnel to initiate initial diagnostic and management procedures while the organ procurement organization is notified and mobilized.

The ultimate goal of the supply side in transplantation is to increase the number of viable organs transplanted. This can be accomplished by a variety of mechanisms that are not necessarily mutually exclusive. The first is to increase the consent rate of available donors through professional and lay education (22). The second is to increase the size of the potential donor pool by including ‘expanded’ donors, who include older donors and donors with mild disease processes such as diabetes and hypertension (5), and perhaps selected donors with past histories of certain cancers who have previously been excluded solely because of their history of cancer (23). The third mechanism to increase the number of transplanted organs is to optimize donor management, with resultant increases in number of organs transplanted per donor. During this study, the Critical Pathway for the Organ Donor© was able to help meet the goal of increasing the number of organs available through optimum donor management.

Many health-care professionals have recognized the potential value of a standard donor management algorithm to enhance donation outcomes. As a result, the American Society of Transplant Surgeons, the American Society of Transplantation, the North American Transplant Coordinators Organization, and the Association of Organ Procurement Organizations, have endorsed the Critical Pathway for the Organ Donor©.

References

  1. Top of page
  2. Abstract
  3. Introduction
  4. Materials and Methods
  5. Results
  6. Discussion
  7. References
  • 1
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    Shafer T, Huenke M, Wolff S et al. The Texas Nondonor Hospital Project: a preliminary report on the impact of inhouse coordinators on organ donation rates in nondonor hospitals. Transplant Proc 1997; 29: 32613262.
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