Intensive care medicine

Published on 05/05/2015 by admin

Filed under Internal Medicine

Last modified 22/04/2025

Print this page

This article have been viewed 1023 times

15 Intensive care medicine

Questions

Is there any role for heparin in management of septic shock?

Is there more adrenaline (epinephrine) or noradrenaline (norepinephrine) produced in shock? From where do these substances come from?

I hear conflicting views as to whether activated protein C is useful in shock.

Why does both vasoconstriction and vasodilatation occur in shock?

Are pulmonary artery (PA) catheters dangerous?

In most hospitals, what is the difference between a high-dependency unit (HDU) and an intensive care unit (ITU) and what is ‘step down’ care?

What is the difference between acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) from a practical point of view?

What is the role of inhaled nitric oxide (NO) in acute respiratory distress syndrome (ARDS)?

What is meant by ‘positive’ pressure ventilation?

Why is an electroencephalogram (EEG) not used in all countries to evaluate possible brain death.

There is no evidence of any effect on survival in any of the trials for the use of heparin in septic shock, and therefore it is not recommended.

More adrenaline than noradrenaline is produced. Initially, this is from increased sympathetic nervous activity but this is later augmented by production of catecholamines from the adrenal medulla.

You are correct, views are conflicting. Administration of recombinant human activated protein C was shown to improve survival in patients with sepsis-induced shock. A more recent study showed no benefit and the view now is that it should be tried if all else fails.

The initial response in most forms of shock is release of catecholamines, which cause vasoconstriction, increased myocardial contractility and a tachycardia. There is later release of many vasoactive substances, e.g. nitric oxide, which causes vasodilatation.

No; not when used by experts. There is, however, some evidence that PA catheters do not improve outcome and because of the complications and cost; it has been suggested that pulmonary artery catheterization has been overused.

ITU means ‘intensive’ care with facilities to deal with multi-organ failure. The ratio between staff and patients is 1:1. In most hospitals, the ITU is also where invasive ventilation is performed if necessary. HDUs are often used postoperatively or when constant monitoring is required. They are sometimes used as a ‘step down’ from ITU before the patient is transferred to a ward.

In ALI the PaO₂/F_IO₂ ratio is < 40kPA (<300mmHg); in ARDS the ratio is<26kPa (<200mmHg). From a practical point of view, both are treated in the same way; respiratory support and treatment of the underlying condition.

Inhaled nitric oxide reduces pulmonary artery pressure and improves V/Q mismatch. However it has not been shown to improve outcome.

Further reading

Rubenfeld GD et al. (2005) Incidence and outcomes of acute lung injury. New England Journal of Medicine353: 1685–1693.

Gas is delivered under positive pressure into the airways during inspiration. It contrasts with negative pressure ventilation where the chest or whole body is encased in a tank to produce a negative airway pressure in inspiration.

An EEG looks only at cortical activity, and loss of brainstem reflexes is necessary to confirm brain death. In the UK (but not the US) it is considered that an experienced clinician’s examination of the patient makes an EEG unnecessary.

Related

1000 Questions and Answers from Kumar _ Clarks Clinical Medicine