Page 1569 - Hall et al (2015) Principles of Critical Care-McGraw-Hill

1088 PART 10: The Surgical Patient

years, some organ transplants (eg, kidney and pancreas) no longer Therefore, each center has specific transplant protocols. However, as
require routine postoperative admission and monitoring in an inten- a consequence of the resultant modulation of the immune system’s
sive care unit. Lung, liver, and heart transplantation, however, remain surveillance and response functions, the transplant recipient is placed at
challenging from a surgical and anesthesia perspective with risk for risk of developing infections and neoplasms.
hemodynamic and respiratory complications intraoperatively and in the Immunosuppressive therapy can be divided into three phases: induc-
perioperative period. Their long-term outcome depends on the imme- tion, maintenance, and the treatment of acute rejection. The induction
diate postoperative management in the intensive care unit and recent phase commences in the immediate postoperative period and involves
advances in survival have been directly due to improvements in early intense immunosuppression that is usually continued for 2 to 4 weeks.
postoperative care. Although the regimens used at different centers vary, most typically
Given the burden of immunosuppression that these patients face include the use of systemic corticosteroids in conjunction with a calci-
throughout their posttransplant lives, they are at increased risk of neurin inhibitor and a proliferation inhibitor (see below). These agents
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developing severe standard and opportunistic infections prompting may be started intravenously, but are switched to oral formulations to
admission to an intensive care unit. Their lives are further complicated minimize toxicity once the patient is tolerating and absorbing enteral
by acute and chronic rejection that could necessitate intensive care sup- medications and feeds. To avoid some of the renal toxicity associated
port. Knowledge of unique presentations of common illnesses or unique with the calcineurin inhibitors, antithymocyte immunoglobulin or anti–
illnesses that present with common clinical syndromes is imperative for interleukin-2-receptor antibodies (IL-2R Abs) may be substituted in the
the early recognition and timely initiation of appropriate treatment. The early postoperative period.
consequences of missing rejection or infection include death, or graft The maintenance phase follows the induction period and is heralded
failure and return of the patient back to a state characterized by the by a reduction in the intensity of immunosuppression. Typically the
sequelae of end-organ dysfunction. maintenance phase incorporates components of the planned regimen
This chapter focuses on the indications, outcomes, postoperative that will be used to suppress the immune response to the allograft and
management, and postoperative complications of lung, liver, and heart thus prevent rejection over a more prolonged period. Most patients will
transplant. For the transplant intensivist, optimization of the postop- be maintained on either oral prednisone and cyclosporine or tacroli-
erative care and knowledge of the potential complications are necessary mus, although it appears that in some patients receiving tacrolimus for
to enhance outcome. For the nontransplant intensivist, knowledge of maintenance the steroid component may be discontinued completely.
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indications for transplant, supportive care, and optimization of function Azathioprine or mycophenolate mofetil is often used during the main-
prior to transplant is important. An understanding of bridging tech- tenance phase to permit dose reduction of the other immunosuppressive
niques and having an approach to the management of immunosup- drugs in order to minimize side effects.
pressed transplant patients and their unique presentations are imperative The remaining phase of immunosuppressive therapy is not planned
to optimizing their care and long-term outcome. but it is anticipated and involves the treatment of acute rejection. Despite
improvements that have been made in immunosuppressive strategies,
IMMUNOSUPPRESSION episodes of acute rejection still commonly occur in the postoperative
period, typically between 1 week and 1 year following the operation.
To avoid rejection of the allograft by the recipient’s immune system, Early recognition and prompt treatment of acute rejection is essential
therapy with immunosuppressive agents is required. More than one if long-term graft function is to be preserved. Treatment involves an
agent is employed to allow for the targeting of different immunologic intensification of the immunosuppressive regimen, which is usually
effector pathways (Fig. 115-1). Multiple advances in immunology have accomplished through the use of high-dose steroids, short courses of
led to the creation of a variety immunosuppressive agents allowing for antithymocyte globulin, and increased doses of the other immunosup-
different combinations to achieve a desired level of immunosuppression. pressive therapies.

Azathioprine/MMF Azathioprine
Steroids T cells Antithymocyte globulin MMF

IL-1
B cell

T cell T cell
Antigen (cytotoxic) (helper)
presenting
cell IL-2
IL-2R Abs
IL-2
Calcineurin B cells
Antigen Cytokines inhibitors Cytokines
NK cells, PMNs,
LAK cells, cytokines Steroids
Steroids

Antibodies
Allograft
FIGURE 115-1. Sites of action of important immunosuppressive agents used to prevent allograft rejection in transplant recipients (see text for explanation). IL-1, interleukin-1; IL-2, interleukin-2;
IL-2R Abs, anti–interleukin-2-receptor antibodies; LAK cells, lymphokine-activated killer cells; MMF, mycophenolate mofetil; NK cells, natural killer cells; PMNs, polymorphonuclear neutrophils.

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