Page 120 - Medicine and Surgery

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116 Chapter 3: Respiratory system

and steroids. The lung is prone to rejection and patient sufficiently to overcome the obstruction, in the
thus transbronchial biopsies are now used for rou- process of which the patients sleep is disturbed, although
tine monitoring. Infection is common and may be they do not recall it.
severe.
Lung volume reduction surgery has a place in the Clinical features

treatment of some patients with emphysema al- Patientscomplainofcontinualtiredness(90%),andmay
though its role is still under investigation. fall asleep during the day. Less than half notice that they
have a restless or unrefreshing sleep, and about a third
Prognosis complain of morning headache (due to carbon dioxide
50% of patients with severe breathlessness die within 5 retention).Sleepingpartnerswillhavenoticedloudsnor-
years although even in severe cases stopping smoking ing in 95% and often notice the snore–apnoea–choke–
improves the prognosis. snore cycle. Alcohol and smoking should be enquired
about. Classical anatomy is a long soft palate, large neck
Sleep apnoea/Pickwickian syndrome and excess tissue around the tonsils. Systemic hyperten-
sion is common.
Definition
Sleep apnoea represents the cessation of airflow at the
Complications
level of the nostrils and mouth lasting at least 10 seconds,
Oxygen saturations may fall very low. The pulmonary
thepatientissaidtosufferfromsleepapnoeaifmorethan
vasculature responds to hypoxia by vasoconstriction
15 such episodes occur in any 1 hour of sleep.
thus there may be pulmonary hypertension. Hypoxia
also increases arrhythmias and there is an increased risk
Prevalence
of stroke and myocardial infarction. Twenty per cent ex-
1–2% of the general population.
perience reduced libido and even impotence.
Age
Middle age. Investigations
A simple sleep study with overnight pulse oximetry to-
Sex gether with a history from sleeping companion may be
Male preponderance. diagnostic. Many require a full sleep study (polysomno-
gram), which consists of a pulse oximeter, a tidal volume
Aetiology measurement, oronasal flow and electroencephalogra-
Risk factors include obesity, smoking, chronic obstruc- phy to record sleep and arousal patterns. Polycythaemia
tive pulmonary disease and alcohol or other sedatives (raised haemoglobin and packed cell volume) may occur
which exacerbate the problem by causing hypotonia and in advanced cases.
respiratory depression. Apnoea can be divided into the
following: Management
1 Central apnoea when there is depression of the respi- Non-pharmacological treatment includes weight loss,
ratory drive, e.g. opiate overdose. exercise, cessation of smoking and reduced alcohol in-
2 Obstructive apnoea when air is unable to pass despite take. Mechanical obstruction due to nasal deformities,
arespiratory effort. polyps or adenoids may be correctable.
3 Mixed central and obstructive apnoea. 1 Continuous positive airway pressure (CPAP) via a
nasal mask prevents collapse of the upper airway and
Pathophysiology is the mainstay of treatment.
Snoring arises because of turbulent airflow around the 2 Surgicaltreatmentmaybedifficultaspatientsareoften
soft palate with partial obstruction. Critical airway ob- apoor anaesthetic risk.
struction leads to a decrease in arterial oxygen ‘hypop- Uvulopalatopharyngoplasty (UPPP) trimming of
noea’andthenocclusionleadstoapnoea.Thereisareflex the redundant tissues in the soft palate and lateral
increase in respiratory drive, which eventually rouses the pharynx is sometimes performed but its benefit in