Page 371 - ACCCN's Critical Care Nursing

348 P R I N C I P L E S A N D P R A C T I C E O F C R I T I C A L C A R E

● There are several diagnostic tools used for respiratory perfusion scans are more sophisticated devices for
dysfunction in ICU; the chest X-ray is the most patients when high diagnostic skills are needed.
common. Interpretation of a CXR follows a systematic
process designed to identify common pathophysiolog- Careful patient assessment is essential, particularly for
ical processes and locate lines and other items. Bron- respiratory dysfunctions which can be immediately life-
choscopy is a useful bedside diagnostic and therapeutic threatening. Contemporary critical care practice involves
device. Computed tomography provides greater speci- comprehensive clinical assessment skills and use of a
ficity than an X-ray. Ultrasound imaging is a useful range of monitoring devices and diagnostic procedures.
diagnostic tool for patients with fluid in the pleural This challenges a critical care nurse to be adaptable and
space. Magnetic resonance imaging and ventilation/ willing to embrace new skills and knowledge.

Case study

Patricia, a 65-year-old female weighing 82 kg, is admitted to ICU hypoxaemia and uncompensated respiratory acidosis. With her
after a 3-day history of worsening dyspnoea, lethargy, fevers and increasing exhaustion and hypoxia, a decision was made to intu-
a cough productive of yellowish-creamy sputum. She is a non- bate and mechanically ventilate. Patricia’s oxygenation did not
smoker but has a history of mild asthma, and no allergies. Initial improve significantly once mechanically ventilated. Her next arte-
examination by her assigned ICU nurse revealed: rial blood gas on FiO 2 0.8 showed: pH = 7.36, PaCO 2 = 44 (5.9 kPa),
● temperature 38.6 °C PaO 2 = 59 (7.9 kPa), HCO 3 = 22; indicating a normalised acid–base
−
● heart rate 110 beats/min balance but continuing hypoxia. Capnography was commenced to
● blood pressure 110/60 mmHg track her PetCO 2 levels and they remained constant at between
● respiratory rate 36 breaths/min 38–42 mmHg (5–5.6 kPa). A bronchoscopy was performed to visu-
● pulse oximetry 89% on 15 L/min via a non-rebreather oxygen ally inspect and toilet the airway. Marked inflammation of the
mask airways and copious tenacious mucous plugs was evident. The
● use of accessory muscles and nasal flaring evident mucous plugs and sputum were removed and sent for MCS; a
● unable to speak in sentences and appears exhausted bronchoalveolar lavage was performed and sent for viral studies
● auscultation of lung sounds revealed coarse crackles and bron- and MCS; the airways were toileted; and the position of the endo-
chial breathing in the left lower lung area tracheal tube was confirmed.
● chest X-ray demonstrated shadowing of the left lower lobe
with associated loss of the costophrenic angle indicating Patricia’s oxygenation improved after the bronchoscopy. Over the
pleural effusion next 12 hours her oxygen requirements decreased. On day 2 of ICU
admission, MCS showed Streptococcus pneumoniae, therefore cef-
The medical officer ordered an arterial blood gas (after placement triaxone was continued and azithromycin was ceased. Patricia con-
of a radial arterial line); blood cultures to be collected to isolate an tinued to respond well to antibiotics, and subsequent chest X-rays
infective organism; and a sputum specimen for microculture and over the next 3 days showed resolution of her left sided pleural
sensitivity (MCS). Patricia was diagnosed with left lower lobe effusion without intervention and decreased shadowing of the left
Community Acquired Pneumonia (CAP). She was commenced on lower lobe. Patricia was weaned off mechanical ventilation on Day
a broad spectrum intravenous antibiotic regime of azithromycin 4 of ICU admission and was transferred to the respiratory ward on
500 mg twice daily and ceftriaxone 1 g twice daily. Day 5 on 2 L of oxygen and oral antibiotics. She was discharged
from hospital on Day 10.
Her arterial blood gas on admission to ICU showed: pH = 7.3,
−
PaCO 2 = 50 (6.7 kPa), PaO 2 = 52 (7 kPa), HCO 3 = 24, indicating

Research vignette

Hodgson CL, Tuxen DV, Holland AE, Keating JL. Comparison of fore- prospectively compared the accuracy of a forehead reflectance
head Max-Fast pulse oximetry sensor with finger sensor at high sensor (Max-Fast) with a conventional digital sensor in patients
positive end-expiratory pressure in adult patients with acute respi- with acute respiratory distress syndrome during a high positive end-
ratory distress syndrome. Anaesthesia and Intensive Care 2009; 37: expiratory pressure (PEEP) recruitment manoeuvre (stepwise
953–60. recruitment manoeuvre). Sixteen patients with early acute respira-
tory distress syndrome were enrolled to evaluate the blood oxygen
Abstract saturation during a stepwise recruitment manoeuvre. PEEP was
In the critical care setting it may be difficult to determine an accu- increased from baseline (range 10–18) to 40 cmH 2 O, then decreased
rate reading of oxygen saturation from digital sensors as a result of to an optimal level determined by individual titration. Forehead
poor peripheral perfusion. Limited evidence suggests that fore- and digital oxygen saturation and arterial blood gases were mea-
head sensors may be more accurate in these patients. We sured simultaneously before, during and after the stepwise