Page 338 - ACCCN's Critical Care Nursing

Cardiac Surgery and Transplantation 315

immunosuppressed transplant recipients are at risk of Nursing practice
acquiring opportunistic bacterial, viral or fungal infec- Early detection of haemorrhage is achieved by close mon-
tions; latent infections acquired from the donor organ itoring of the following: haematological status; chest tube
such as cytomegalovirus (CMV); or reactivation of their patency, drainage volume and drainage consistency;
own latent infections (e.g. CMV or Pneumocystis carinii). and trends in haemodynamic data that suggest cardiac
To combat Pneumocystis carinii, patients receive trime- tamponade (see earlier in this chapter). Our clinical expe-
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thoprim with sulfamethoxazole twice weekly. Despite rience suggests that if patients are hypotensive sporadi-
preoperative screening for CMV, the shortage of donor cally for no readily apparent reason, efforts should be
organs often necessitates CMV mismatching. Effective made to eliminate the existence of cardiac tamponade.
prophylaxis for CMV infection is provided by administer- Suspicion of cardiac tamponade may be confirmed
ing CMV hyperimmune globulin to CMV-positive and by chest X-ray or echocardiogram if the patient’s haemo-
CMV-negative recipients who receive a heart from a sero- dynamic status is stable. Sudden cardiac arrest or haemo-
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positive donor. This commences within 24–48 hours of dynamic collapse secondary to cardiac tamponade
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surgery. For CMV-negative recipients of organs from warrants an immediate return to theatre or a sternotomy
seropositive donors, ganciclovir for 1–2 weeks followed in critical care.
by oral therapy for 3 months is required in addition to
CMV hyperimmune globulin. 111-113
Acute Renal Failure
Nursing practice Acute renal failure or varying degrees of renal dysfunction
can occur in the initial postoperative period due to pre-
To prevent infection, standard precautions and meticu- existing renal dysfunction, cyclosporin, nephrotoxic anti-
lous hand-washing (see Chapter 6) are performed, rather biotics, or sustained periods of hypotension secondary to
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than isolation procedures. Mandatory measures to cardiopulmonary bypass or allograft dysfunction. Diuretic
prevent overwhelming sepsis are a high level of vigilance therapy is invariably needed in the initial postoperative
by clinicians for signs of infection; obtaining empirical period due to these factors, as well as the fluid retention
evidence from blood, sputum, urine, wound and catheter- effects of corticosteroids and raised filling pressures
tip cultures; and aggressive and prompt treatment for secondary to a transient loss of right and/or left ventricu-
specific organisms. Although typical signs and symptoms lar compliance. High doses or continuous infusions
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of infection are blunted in transplant recipients, clini- of diuretics may be required in patients who were on
cians should suspect infections when patients have a diuretic therapy preoperatively. Close monitoring of
low-grade fever, hypotension, tachycardia, a high cardiac serum electrolyte levels will indicate the need for any
output/index, a decrease in systemic vascular resistance supplements.
(SVR), changes in mentation, a new cough or dys-
pnoea. 115,116 Elevated white cell count, the presence of Nursing practice
dysuria, purulent discharge from wounds, infiltrates on
chest X-ray, sputum production or pain also indicate In addition to all the usual nursing and collaborative
infection. measures that are taken to prevent, detect and support
renal dysfunction/failure in patients following cardiac
Prior to administering blood products, nurses must ascer- surgery on cardiopulmonary bypass (see earlier in this
tain the CMV status of the patient and donor. Recipients chapter and Chapter 18), the type and dose of immuno-
who are seronegative for CMV and who receive a heart suppressive agents in the postoperative period are care-
from a seronegative donor must receive whole blood, fully selected and initiated according to individual risk
packed/red cells or platelets that are CMV-negative, leuco- factors and clinical status. Experience suggests that early
depleted or both in order to avoid development of a intervention with haemofiltration to support renal func-
primary CMV infection. 79,112,117 tion is preferable to continued use of high-dose diuretics
and deferred haemofiltration. This is because there is
Haemorrhage/Cardiac Tamponade little scope to maintain low doses of renal toxic immuno-
The risk of haemorrhage or cardiac tamponade is greater suppressants for weeks given the imminent risk of rejec-
for heart transplant recipients than for patients undergo- tion and resultant allograft failure.
ing coronary artery bypass graft or valvular surgery. Pre-
operative anticoagulation for end-stage heart failure or Early Allograft Dysfunction and Failure
atrial fibrillation, impairment of hepatic function second- Primary allograft failure is the leading cause of death in
ary to right heart failure, redo surgery, surgical suture the first month and year after surgery. 120,121 In the immedi-
lines connecting major vessels and atria, and a larger ate postoperative period, myocardial performance is
than usual pericardium are all contributing factors. depressed due to the clinical sequelae of cardiopulmo-
Good surgical technique is mandatory in preventing post- nary bypass and ischaemic injury associated with surgical
operative bleeding. As the promotion of haemostasis is a retrieval, hypothermic storage, prolonged ischaemic
major therapeutic goal postoperatively, blood products, times, and reperfusion. Despite a preferred time period
procoagulants and antifibrinolytics are commonly between organ retrieval and reimplantation of 2–6 hours,
administered according to laboratory and clinical data. the vast distances between capital cities (up to 3000 km)
Postoperative mortality from bleeding has been reported over which donor hearts may be transported, and a
to occur in up to 6.7% of cases. 118 decision to accept marginal, suboptimal organs, led