Renal replacement therapy in the ICU: The Australian experience

Renal Replacement Therapy in the ICU: The Australian Experience Rinaldo Bellomo, MBBS, MD, Louise Cole, MBBS, John Reeves, MBBS, and William Silvester, MBBS 0 The structure of health care drives medical practice in a powerful way, shaping choices of therapy and approaches, and influencing scientific evidence. The Australian experience with continuous renal replacement therapy (CRRT) confirms the importance of structure. A public health system like that of Australia’s contains the following variables: well-developed intensive care tradition and expertise, a dominant “closed” intensive care unit (ICU) model, well-developed training of intensive care nurses with established one-to-one nurse-patient ratios, salaried medical practitioners, overworked general dialysis units with inadequate nursing resources, and lack of fee-for-service incentive for nephrologists to see ICU patients with acute renal failure. The likely outcome of such a system is for CRRT to be run by intensive care staff. As shown by a recent regional survey, this approach, although somewhat unique, is dominant and appears to work well with excellent clinical results and constant clinical research output. 0 1997

by the National

Kidney

Foundation,

INDEX WORDS: Hemofiltration;

intensive

Inc.

care; acute renal failure.

T

HE RENAL replacement technique of choice for critically ill patients remains a matter of controversy.1S2 The controversy exists because of the lack of controlled randomized evidence to support the use of one particular therapy among those currently available. In the absence of level I evidence to guide critical care physicians or nephrologists in their selection of a modality for renal replacement therapy (RRT), other factors have played a powerful role. These factors include the organization of medical care delivery in a given country, the availability of resources, the demarcation of tasks in the care of critically ill patients, the financial rewards for the delivery of a given type of care, and the institutional availability of a particular level of expertise. Because of these factors, the approach to RRT in the intensive care unit (KU) has been very different from country to country. In this regard, Australia has been unique in its approach because of the complete dominance of continuous renal replacement therapy (CRRT) techniques and because of the control of critical care

From the Department of Intensive Care Medicine, Austin and Repatriation Medical Centre, Melbourne; and the Department of Intensive Care Medicine, Alfred Hospital, Melbourne, Australia. Address reprint requests to Rinaldo Bellomo, Intensive Care Unit, Austin and Repatriation Medical Centre, Heidelberg, Victoria 3084, Australia. E-mail: [email protected]. edu.au 0 1997 by the National Kidney Foundation, Inc. 0272-6386/97/3005-0413$3,00/O

S80

American

Journal

of Kidney

Diseases,

physicians and nurses in applying these techniques.

prescribing

THE AUSTRALIAN HEALTH CARE AND THE ICU

and

SYSTEM

The Australian health care system differs significantly from both the American and European systems. Its features have been recently reviewed in detail3 and have had an important influence on the care of critically ill patients with acute renal failure (ARF). In brief, hospitals where ARF is treated can either be public (mostly) or private (some). All Australians have the right to free health care under the public hospital system. However, there is a substantial private health care system that is, in part, supported by the govemment. Close to one-third of Australians are covered by a private insurance scheme that entitles them to receive care in a private hospital from a doctor of their choice. Doctors in public hospitals are generally in a salaried position, and have little financial incentive to provide extra services. Their resources are controlled by the state, and are allocated to given centers according to perceived or documented needs within the budgetary allocations of the state. In the private system, physician remuneration, on the other hand, is based on a fee-for-service system, but fees are regulated by the government through a process of regular negotiation with specialist colleges, the Australian Medical Association, and other advisory bodies. This system has affected the delivery of critical care medicine. The lack of additional financial incentives within the public

Vol 30, No 5, SuppI

(November),

1997:

pp S80-583

RENAL Table

REPLACEMENT 1. Procedures

THERAPY

IN AUSTRALIA

Now Performed lntensivists

Initial Specialty

Procedure

Endotracheal intubation Percutaneous tracheostomy Right heart catheterization Fiberoptic bronchoscopy Fiberoptic gastroscopy Transesophageal echocardiography Insertion of intracranial pressure monitoring device Insertion of intraaortic balloon counterpulsation device Renal replacement therapy

by Australian

anesthesiology surgery cardiology pulmonology gastroenterology cardiology

neurosurgery

cardiology/cardiac

surgery

nephrology

hospital system has produced a “closed” ICU model. In this model, the critical care physician is responsible for overall patient management, and consults other specialities only as required. Other specialists are generally not allowed to prescribe therapy for critically ill patients, and can only influence their management through consultation with the intensive care specialist and the reaching of a consensus. In many cases, participation in overall patient management by the “parent’ ’ unit is minimal during the patient’s stay in the ICU. This culture has created an environment that makes the development of therapeutic independence desirable. Australian critical care physicians, therefore, have taken up several procedures normally performed by other specialists, and have made them their own. A list of such procedures is presented in Table 1. This modus operandi, which is the norm in public hospitals, has then been taken up in private hospitals, where ICU specialists continue to interact with non-ICU specialists through a ‘ ‘closed” ICU model. The medical model of critical care management has had significant repercussions on the type of nursing activities conducted by the critical care nurse within the ICU. Australian critical care nurses have, therefore, also taken up several activities that, in other countries, are often performed either by specialized technicians or by specialized nurses. Such activities include the

measurement of arterial blood gases, the measurement of hemodynamic parameters, the administration of inhaled medications, manipulation of ventilator settings, titration of vasoactive medications, and the operative management of CRRT. It is in this environment that novel techniques of renal replacement have been implemented. It is not surprising, therefore, that Australian intensivists have embraced these techniques with gusto: they enable the intensivist to become independent of renal physicians, they fit in well with the physiological approach to patient care inherent to the critical care environment, and they can be prescribed in a system with a ready-made nursing structure to support their implementation. In addition, Australian ICUs have traditionally relied on highly trained nurses operating in a 1: 1 nurse-to-patient ratio. This strong nursing manpower availability has compensated for the general inability to provide senior ICU fellow coverage on a 24-hour basis. Once again, it has also provided the ideal environment for the introduction of CRRT in that it has removed the extra nursing costs potentially associated with its implementation. Within this ICU structure, therefore, both the medical and nursing costs of patient care are less with continuous therapies than they would be with intermittent hemodialysis. Intermittent hemodialysis would, in fact, require allocation of a specialist dialysis nurse and the additional medical input of a nephrologist. Furthermore, in a health environment driven toward decreased expenditure, resources allocated to dialysis centers have been less than ideal, resulting in serious logistic difficulties in situations in which a dialysis nurse has to be removed from the dialysis unit and allocated to the care of an ICU patient with ARF. In this health structure, the predictable outcome has indeed taken place: CRRT is the dominant form of treatment, nephrological input is minimal, the critical care physician and nurse operate independently of the nephrology department, and they are fully in charge of the care of patients with ARF in the ICU. THE CONSEQUENCES

The uniqueness of the Australian experience makes it a useful crucible for the assessment of the robustness of a system that operates indepen-

BELLOMO Table

2. Differences and Intensivist-Based

Between Nephrologist-Based Approaches to RRT

Nephrologist-based approach Preference for urine microscopy in all cases More frequent use of renal ultrasonography in-hours RRT common Out-of-hours start of RRT rare Reliance on conventional techniques Later initiation of RRT Morning prescription and twice daily review Intensivist-based approach Fewer diagnostic investigations Frequent out-of-hours start of RRT Preventive RRT rather than reactive RRT Reliance of continuous RRT Early application of RRT Tighter control of fluid balance Hour-to-hour titration of therapy

dent of nephrological input, and is based on CRRT. The consequences of this change from a conventional dialysis-based nephrologist-prescribed system (early 1980s) to one based on continuous therapy in the hands of the intensivist (late 1980s and 1990s) has already been thoroughly documented by Bellomo et a1.4-6The main differences between the two approaches as they were/are practiced in Australia are summarized in Table 2. To further document current practice, a brief national survey was conducted in 1995 (T. Jones, RN, personal communication, October 1995). This survey revealed that, out of 42 adult tertiary ICUs, 40 were using continuous therapies as the dominant approach to ARF. Intermittent hemodialysis was used in two units and peritoneal dialysis was not used by any. The technique of continuous hemofiltration was variable from unit to unit, with continuous venovenous hemodiafiltration (CVVHDF) appearing to be the most common. We recently (September 1996) chose to conduct an in-depth survey of ARF mangement in the state of Victoria (capital: Melbourne, population 4 million), which is quite representative of practice around Australia. This survey was conducted prospectively over 3 months by means of a comprehensive questionnaire focusing specifically on ICU patients with ARF requiring RRT. With preliminary results available for close to 60% of patients studied, several clear patterns

ET AL

have already emerged. First, CRRT is the dominant form of artificial renal support, with 90% of patients receiving it as the sole or main mode of treatment, and 10% receiving it in a modified version for 8 to 12 hours during the day. Second, patient management is solely in the hands of the intensivist in 70% of cases and mostly in the hands of the intensivist with some nephrological input in 30%. On the other hand, nursing management of RRT is 100% under the control of the critical care nurse, with no dialysis nurse input. The etiology of renal failure in these patients is summarized in Fig 1. The preferred techniques of continuous hemofiltration were either continuous venovenous hemofiltration or CVVHDF, approximately even in frequency, with control of ultrafiltration rate by volumetric pump being applied to about 50% of patients and with the remaining 50% having spontaneous ultrafiltration. Polyacrylonitrile membranes were the most common type of membrane in use. CONCLUSION

In Australia, the management of ARF is “geographically” split. When ARF is uncomplicated and occurs in a ward patient, it is managed by the nephrologist and dialysis nurse, and therapy is intermittent. When ARF is complicated and occurs in the ICU, it is managed by the intensivist and critical care nurse, and therapy is continuous. This structure of ARF management is essentially the consequence of the organization of health care in Australia and is associated with excellent patient outcomes.’ In this environment, it is im-

Septicshock

Fig 1. causative in Victoria.

lschemia

Hypotension

Histogram showing the factors among patients

~’ Other

distribution with ARF

of main in the ICU

RENAL REPLACEMENT

THERAPY IN AUSTRALIA

possible to conduct randomized controlled studies comparing intermittent to continuous therapies. Australian intensivists have little interest in the hemodialysis versus continuous hemofiltration controversy and will continue to apply the latter almost exclusively to patient care until further advances bring forth a better alternative. REFERENCES 1. Bellomo R, Mehta R: Acute renal replacement in the intensive care unit: Now and tomorrow. New Horizons 3:760767, 1995 2. Bellomo R, Boyce N: Does continuous hemodiafiltration improve survival in patients with critical illness and associated acute renal failure? Semin Dial 6:16-19, 1993

S83 3. Peabody JH, Bickel SR, Lawson JS: The Australian health care system: Are the incentives down under right side up? JAMA 276:1944-1950, 1996 4. Bellomo R, Farmer M, Parkin G, Wright C, Boyce N: Severe acute renal failure: A comparison of acute continuous hemodiafiltration and conventional dialytic therapy. Nephron 7159-64, 1995 5. Bellomo R, Mansfield D, Rumble S, Shapiro J, Parkin G, Boyce N: Acute renal failure in critical illness: Conventional dialysis versus acute continuous hemodiafiltration. ASAIO J 38:M654-M657, 1992 6. Bellomo R, Ronco C: Acute renal failure in the intensive care unit: Adequacy of dialysis and the case for continuous therapies. Nephrol Dial Transplant 11:424-428, 1996 7. Bellomo R, Boyce N: Acute continuous hemodiafiltration: A prospective study of 110 patients and a review of the literature. Am J Kidney Dis 21:508-518, 1993