Page 576 - ACCCN's Critical Care Nursing

Management of Shock 553

mediated in part by cytokines that upregulate the expres- Initial Management: Diagnosis, Source
sion of inducible nitric oxide synthase in the vasculature. Control and Antimicrobial Therapy
Vascular response to the vasodilatory effect of nitric oxide Identifying and removing the source of infection and
and the activation of ATP-sensitive potassium channels treating the infection with appropriate antimicrobial
combine to cause closure of the voltage-gated calcium therapy are the mainstays of therapy for a patient with
channels in the cell membrane. As the vasoconstrictor sepsis. Australian data indicate that in the ICU setting the
effect of noradrenaline and angiotensin II depend on most prevalent site of primary infection is pulmonary,
open calcium channels, lack of response to these pressor followed by abdominal, together accounting for 70% of
hormones that are central to compensatory mechanisms cases. Similar epidemiology is reported in international
86
in shock can occur with the inevitable failure of delivery sepsis studies. 104,105 In 2005, ICU pneumonia practices
of oxygen to the functional mitochondria resulting in were studied in 14 ICUs and demonstrated a ventilator
99
lactic acidosis in patients with sepsis. With high circulat- associated pneumonia (VAP) incidence of 28%. A
106
ing levels of endogenous vasoactive hormones during further cohort study comparing Australian and Danish
sepsis, downregulation of their receptors occurs.
hospitals noted a lower incidence of VAP with a concomi-
tant increase in broad spectrum antibiotics prescribed
NURSING PRACTICE AND COLLABORATIVE based on clinical signs and multiresistant organisms at
MANAGEMENT the Australian site. 107
As with other forms of shock, initial management includes To provide patients with appropriate antimicrobial treat-
not only acting to correct physiological deterioration by ment for targeting the infecting organism, obtaining
initiating fluid management and frequent observation appropriate samples prior to instigating antimicrobial
and assessment, but also addressing the underlying cause therapy is the clinical standard, although any prescribed
of sepsis through source (of infection) control. treatment should not be delayed as time to antibiotic
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administration is important in severe sepsis. In one
Initial Management: Fluid Resuscitation large retrospective study, every additional hour to effec-
Measuring surrogate markers of preload as an indicator tive antimicrobial initiation in the first 6 hours after onset
of volume status is a contentious issue, as CVP as a of hypotension was associated with >7% decrease in sur-
108,109
measure of preload is not a good marker of volume vival. Optimising dosage to achieve a therapeutic
responsiveness. 32,100 While CVP was used in sepsis trials concentration is also important. Current practice is to
of early goal-directed therapy (EGDT) protocols 35,101–103 continuously infuse glycopeptides to maintain a serum
and is an often documented endpoint of resuscitation, concentration above the minimum inhibitory concentra-
EGDT has been widely discussed and criticised in the tion and therefore kill microbes more effectively. More
literature. Australian data indicates that the incidence of recently there has been evidence that β-lactams should
110
patients meeting the criteria and mortality is lower than also be infused. Recently a paradigm shift has been
36
the treatment group in the original EGDT trial. This is suggested in relation to antimicrobial therapy; to get it
currently the focus of a large trial by the ANZICS Clinical right the first time with high doses, while limiting the
Trials Group (ARISE). 36 duration of therapy and the potential to increase
resistance. 111
Fluid resuscitation with crystalloid or colloid has long
been controversial in the critical care literature. The land- Where a patient is able to respond appropriately during
mark Saline versus Albumin Fluid Evaluation (SAFE) history and physical assessment, timelines of the infective
44
study demonstrated that in the adult intensive care process should be documented. Sites considered as infec-
patient population, albumin can be considered safe, tive sources include decubitus ulcers, invasive lines,
without demonstrating any clear advantage over saline. drains, wounds, sinuses, ears, teeth, throat, chest, blood,
In the study conducted in 14 Australian and 2 New lungs, back, abdomen, perianal, genital/urinary tract,
Zealand ICUs, 6997 patients were randomised to receive bones and joints. More invasive sampling may include
either saline (n = 3500) or albumin (n = 3497). No sig- bronchioalveolar lavage, CSF, pleural fluid, abdominal
nificant differences were noted between the two treat- collections or biopsy of other sites as clinically appropri-
ment groups for 28-day all-cause mortality, days in ate. X-rays, CT Scans and surgical consultation will also
intensive care, days in hospital, days on mechanical ven- be a priority.
44
tilation and days of renal replacement therapy. The Sur- Minimum continuous monitoring includes ECG, blood
viving Sepsis Campaign guidelines do not advocate one pressure, pulse oximetry and other measures to assess
89
preferred resuscitation fluid. Irrespective of fluid selec- preload and volume responsiveness, along with regular
tion, the disruption of the vascular bed in early septic assessment of lactate, oxygenation and markers of inflam-
shock through widespread vasodilatation results in mation and coagulation.
increased capillary permeability and rapidly developing
interstitial oedema. Large amounts of fluid can be admin-
istered without seemingly improving oxygen delivery Ongoing Collaborative Management:
whilst adding to developing generalised oedema which Drug Therapy
further impairs cellular delivery of oxygen and nutrients. A range of drug therapies aimed at supporting and ame-
Fluid resuscitation alone is therefore of limited value in liorating the signs and symptoms of septic shock are
septic shock and other measures must be considered. available and whilst inotropes in particular provide an