Page 380 - ACCCN's Critical Care Nursing

Respiratory Alterations and Management 357

of respiratory infections, while cardiovascular and renal prevent microorganisms entering the lungs, such as par-
disease impact on disease severity and the management of ticle filtration in the nostrils, sneezing and coughing to
many respiratory alterations. Other factors such as smoking expel irritants and mucus production to trap dust and
and alcohol use, living conditions and lifestyle impact infectious organisms and move particles out of the respi-
on the predisposition and clinical course of an illness. ratory system. Infection occurs when one or more of
these defences are not functioning adequately or when
Post-anaesthesia Respiratory Support an individual encounters a large amount of microorgan-
6
Short-term respiratory support may be required after isms at once and the defences are overwhelmed. An
major surgery, in cases of extended anaesthesia, preexist- invading pathogen provokes an immune response in the
ing comorbidities and/or diminished physical reserve lungs, resulting in the following pathophysiological
(e.g. elderly, patients with obstructive sleep apnoea). processes:
Most patients requiring ventilation in the early post- ● alteration in alveolar capillary permeability that leads
operative period have had cardiothoracic surgery, and so to an increase in protein-rich fluid in the alveoli; this
much of the available research relates to this patient impacts on gas exchange and causes the patient to
group (see also Chapter 12). breathe faster in an effort to increase oxygen uptake
Preoperative assessment and management is a key factor and remove CO 2
in preventing respiratory complications. This involves ● mucous production increases and mucous plugs may
optimising physical condition and nutritional status, develop which block off areas of the lung, further
planning the timing of surgery to reduce the likelihood reducing capacity for gas exchange
of preexisting respiratory infection and patient education ● consolidation occurs in the alveoli, filling with fluid
regarding the importance of respiratory support, includ- and debris; this occurs particularly with bacterial
ing postoperative mobilisation and physiotherapy. pneumonia where debris accumulates from the large
Patients with suspected or confirmed chronic conditions number of white blood cells involved in the immune
6
require a thorough diagnostic work-up prior to surgery to response.
determine the best management strategy in the post-
operative period. 17 AETIOLOGY
Pneumonia is caused by a variety of microorganisms,
The key focus in management of postoperative ventilation including bacteria, viruses, fungi and parasites. In many
is to limit ventilation time, as prolonged ventilation time cases, the causative organism may not be known and
is associated with poor outcome. Once a patient has current practice in many cases is to initiate antimicrobial
reached normothermia, is haemodynamically stable, treatment as soon as possible, based on symptoms and
responsive and has adequate analgesia, weaning of venti- patient history, rather than waiting for microorganism
lation is commenced. Rapid and/or nurse-led weaning culture results. The true incidence of pneumonia is not
19
protocols are often implemented to minimise delays in well known as many patients do not require hospitalisa-
the weaning process. Anaesthetic care in these patients tion. Different ages and characteristics of the patient are
includes use of short-acting or regional anaesthesia (e.g. often associated with different causative organisms. Viral
epidural analgesia) to minimise respiratory depression. 18
pneumonias, especially influenza, are most common in
young children, while adults are more likely to have
PNEUMONIA pneumonia caused by bacteria such as Streptococcus
pneumoniae and Haemophilus influenzae. Pneumonia is a
Pneumonia is infection of the lung. Depending on the
type and severity of the infection and the overall health particular concern among elderly adults as they experi-
of the person, it may result in ARF. Pneumonia can be ence an increase in the frequency and severity of
6
caused by most types of microorganisms, but is most pneumonia.
commonly a result of bacterial or viral infection. In criti- Table 14.4 outlines the principal diagnoses of patients
7
cal care the key distinctions in assessing and managing a hospitalised with pneumonia in Australia during 2007–
patient with pneumonia relate to the specific aetiology or 2008. This information reflects the high proportion of
causative organism. This section reviews the aetiology, viral pneumonia and the large number of cases where the
pathophysiology, clinical presentation and management causative organism may not be known.
of two types of pneumonia:
● community-acquired pneumonia (CAP) Community-acquired Pneumonia
● ventilator-associated pneumonia (VAP) Clinical assessment, especially patient history, is impor-
tant in distinguishing the aetiology and likely causative
The issue of epidemic or pandemic respiratory disease as
a result of viral infections is included in the following organism in patients with community-acquired pneumo-
Respiratory pandemics section. nia (CAP). Specific information regarding exposure to
animals, travel history, nursing home residency and any
occupational or unusual exposure may provide the key
PATHOPHYSIOLOGY to diagnosis. Personal habits such as smoking and
9
The normal human lung is sterile, unlike the gastrointes- alcohol consumption increase the risk of developing
tinal tract and upper respiratory tract which have resident pneumonia and should be explored. Many patients
bacteria. A number of defence mechanisms exist to admitted to hospital or ICU with CAP have