Page 592 - ACCCN's Critical Care Nursing

Multiple Organ Dysfunction Syndrome 569

vasopressor requirements and early lower mortality, but Hypocalcaemia
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no difference in 1-year survival. A multicentre trial dem- Hypocalcaemia is common in patients with SIRS, and
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onstrated that hydrocortisone administration did not affects myocardial contractility and neuromuscular func-
improve survival in patients with septic shock. Shock tions. The link between neuromuscular changes such as
reversal was shorter in patients who received hydrocorti- polyneuropathy or polymyopathy and critical illness has
sone, but there were more episodes of infection including not been established beyond early investigations into
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new sepsis and septic shock. Although the largest trial corticosteroid use, neuromuscular blocking medication
of corticosteroids in patients with septic shock, the study administration and prolonged mechanical ventilation. 61
was not adequately powered to detect a clinically impor-
tant treatment and so findings are to be interpreted with
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caution. It is therefore appropriate to reserve corticoste- NEUROLOGICAL DYSFUNCTION
roids for patients with septic shock whose blood pressure Recent evidence has highlighted that multiple organ dys-
is poorly responsive to fluid resuscitation and high dose function can result from severe traumatic brain injury
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vasopressor therapy. Long-term treatment with cortico- (TBI) or subarachnoid haemorrhage (SAH) (see Chapter
steroids may result in an inadequate response of the 17). Cardiovascular and respiratory dysfunction contrib-
adrenal axis to subsequent stress such as infection, surgery ute to mortality in approximately two-thirds of all deaths
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or trauma, with resulting onset or worsening of shock. following severe TBI. In non-traumatic SAH the inci-
Other studies using corticosteroids for adrenal insuf- dence and importance of life-threatening conditions
ficiency in critically ill patients demonstrated lower from non-neurological physiology has been identified,
mortality. e.g. 8 including lethal arrhythmias, myocardial ischaemia and
dysfunction and neurogenic pulmonary oedema. The
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Corticosteroid administration is associated with hyper- cause of cardiovascular and respiratory organ dysfunction
glycaemia and may affect patient outcomes, necessitating following these acute severe neurological events is associ-
insulin therapy to normalise blood glucose levels. A ated with dysfunction of the sympathetic nervous system.
recent multicentre trial (Corticosteroids and Intensive Beta blockers may modulate the sympathetic storm
Insulin Therapy for Septic Shock [COIITS]), demon- resulting from severe neurological injury. 62
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strated that intensive insulin therapy did not improve
in-hospital mortality for patients treated with hydrocor- Critically ill patients may develop a syndrome of neuro-
tisone and oral fludrocortisones for septic shock. muscular dysfunction characterised by generalised muscle
weakness and an inability to wean successfully from
Glycaemia Control mechanical ventilation. Critical illness neuromyopathy
syndromes (CINM) or ICU-Acquired Weakness (ICU-
Hyperglycaemia is common in critically ill patients as a AW) has been associated with risk factors including
result of stress-induced insulin resistance and accelerated hypergylcaemia, SIRS, sepsis, MODS, renal replacement
glucose production, and excessive circulating levels of therapy, glucocorticoids, neuromuscular blocking agents
glucagon, growth hormone, sympathomimetics and glu- and catecholamine administration. The risk of CINM/
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cocorticoids (see Chapter 19). An increased caloric intake ICU-AW is nearly 50% in patients with sepsis, MODS or
from parenteral or enteral nutrition will also increase protracted ventilation, with short-term survival uncer-
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glucose levels. Hyperglycaemia has undesirable effects tain. Glycaemic control may be a potential strategy for
such as fluid imbalance, immune dysfunction, promoting decreasing CINM/ICU-AW risk. 63
inflammation, abnormalities in granulocyte adherence,
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chemotaxis, phagocytosis and intracellular killing. Survivors of sepsis-induced multiple organ dysfunction
Resulting associations between hyperglycaemia and may also suffer long-term cognitive impairment, includ-
adverse clinical outcomes have been reported in many ing alterations in memory, attention, concentration and/
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observational studies. Potential benefits of exogenous or global loss of cognitive function. The participation
insulin administration include normalising immune of the brain during sepsis is poorly understood; septic
functional, improving oxygen delivery to ischaemic areas encephalopathy is the more common neurological dys-
of myocardium, tissue repair and preventing transfusion, function, accounting for up to 70% of brain dysfunc-
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dialysis and critical illness polyneuropathy. Intensive tions. Chapter 4 described the physical, psychological
insulin therapy has also been suggested to improve mor- and cognitive sequelae for survivors of a critical illness
bidity, reducing the risk of sepsis, excessive inflammation during their recovery.
and multiple organ failure, transfusion requirements and
dependence on mechanical ventilation. 59 MULTIORGAN DYSFUNCTION
The Normoglycaemia in Intensive Care Evaluation and MODS contributes to significant morbidity and use of
Survival Using Glucose Algorithm Regulation Study intensive care resources worldwide. Patients with MODS
(NICE-SUGAR) examined tight glycaemic control with have an increased ICU length of stay when compared to
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insulin during critical illness. Maintaining blood glucose high-risk patients without multiple organ involvement.
at less than 10 mmol/L resulted in 10% reduction in The epidemiology of MODS is changing however, with
90-day mortality compared to a tighter glycaemic control studies in post-injury organ failure indicating a reduction
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target (4.5–6.0 mmol/L). Lower target blood sugar in incidence, disease severity, duration and mortality. 65,66
levels are therefore not recommended for managing gly- Mortality ten years ago was estimated at 40–60%, rising
caemia in critical ill patients. with subsequent organ dysfunction. 42,67,68 More recent