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Respiratory Alterations and Management 375

Case study, Continued

An additional peripheral intravenous line was inserted in ED. The that there was no shunt. The plan was to reduce the PEEP to
clinical impression was pneumonia secondary to possible H1N1 reduce the shunting and by day 4 of ICU the hypoxaemia had
Influenza A (swine flu). The decision was made to transfer Frances resolved.
directly to ICU where an arterial line was promptly inserted for
monitoring, followed by an elective endotracheal intubation for On day 9 of ICU, following an additional 161 hours of intubation,
respiratory distress. She was administered morphine and mid- Frances was extubated again and received high flow oxygen via
azolam sedation. Ceftriaxone, azithromycin, vancomycin and osel- nasal prongs. During the next 3 hours Frances complained of dif-
tamivir were commenced. A central venous catheter was inserted ficulty breathing with no apparent increase in her work of breath-
for fluid administration and inotropic therapy if required. The aim ing or alterations in arterial blood gases. An audible stridor and
was to maintain a mean arterial blood pressure (MAP) > 70 mmHg. bovine cough developed despite administration of nebulised
Her first arterial blood gas showed a respiratory acidosis with meta- adrenaline, intravenous steroids and application of BiPAP. Frances
bolic compensation (FiO 2 1.0, PO 2 197 mmHg; PCO 2 42 mmHg; pH was re-intubated; a Grade 1 airway was evident with oedematous
7.33; BE-9; bicarbonate 22 mmol/L and SaO 2 99%). epiglottis and vocal cords sighted. On day 10 of ICU percutaneous
tracheostomy (size 8) was inserted.
By day 1 of her ICU stay, Streptococcus had been identified in the By day 12 of ICU, following an additional 81 hours of ventilation,
blood cultures. Legionella was not detected. Frances remained Frances was successfully breathing via a tracheostomy-shield and
under respiratory isolation precautions pending PCR results. Venti- oxygenation was adequate. Frances was transferred to the ward on
lation settings were FiO 2 0.3, rate 18, V T 500 mL, PEEP 5 cmH 2 O, day 15 of her admission following more than 24 hours of successful
pressure support 10 cmH 2 O. A noradrenaline infusion was com- breathing via a tracheostomy shield. Antibiotic therapy continued
mence to maintain a MAP >70mmHg. Ongoing enteral feeding and while on the ward and her tracheostomy was removed later that
prophylactic VTE management had commenced. day. Frances remained haemodynamically stable and her health
By day 2 of ICU, the PCR repeat testing again returned a negative continued to rapidly improve so that three days later Frances was
result and respiratory isolation precautions were ceased. Following discharged home to convalesce with her family.
39 hours of intubation, Frances was extubated and maintained an Frances attended a clinical review in the ambulatory care depart-
oxygen saturation greater than 96% with FiO 2 0.5 and humidifica- ment four weeks after her ICU discharge. Her recovery had pro-
tion. Within the next ten hours Frances was re-intubated as she was gressed to the point that she reported being able to walk two
visibly exhausted with an increased work of breathing, and an kilometres (her baseline tolerance was five kilometres). On exami-
increased respiratory rate from 24 to 35 breaths/minute. Further, a nation her lung fields were clear, her oxygen saturation was 98%
reduced GCS and increasing FiO 2 requirement (0.8) to maintain her on room air and her CXR was clear indicating full resolution of
oxygen saturation supported the need for assisted ventilation. the pneumonia. Her blood pressure remained elevated at
Prior to reintubation her ABG result was PO 2 55 mmHg, PCO 2 150/70 mmHg and she was advised to remain on amlodipine and
48 mmHg, pH 7.35, BE 0.9, HCO 3 26 mmol/L and SaO 2 98%.
−
consult her GP for further follow-up and repeat prescriptions.
On day 3 of ICU, Frances’ oxygenation began to deteriorate with Frances was discharged from the ambulatory care clinic following
changes in positioning. Blood-stained sputum was being suc- this clinical review, with ongoing care to be provided by her GP.
tioned via the ETT. A computed tomography angiogram (CTA) of Frances experienced pneumonia post an initial viral illness. Her
the pulmonary vasculature was undertaken and excluded pulmo- plan for the future was to include annual Influenza vaccination in
nary embolus as a cause for the hypoxaemia. It did show that that her health maintenance plan, and timely consultation with health-
there was bibasal and right upper lobe consolidation. There was care workers with any development of unusual respiratory
no evidence of goitre. An echocardiogram bubble study reported symptoms.

Research vignette
Tiruvoipati R, Lewis D, Haji K, Botha J. High-flow nasal oxygen vs Methods
high-flow face mask: A randomized crossover trial in extubated Patients were randomised to either protocol A (n = 25; HFFM fol-
patients. Journal of Critical Care 2010; 25(3): 463–8. lowed by HFNP) or protocol B (n = 25; HFNP followed by HFFM)
Abstract after a stabilization period of 30 minutes after extubation. The
Purpose primary objective was to compare the efficacy of HFNP to HFFM in
Oxygen delivery after extubation is critical to maintain adequate maintaining gas exchange as measured by arterial blood gas. Sec-
oxygenation and to avoid reintubation. The delivery of oxygen in ondary objective was to compare the relative effects on heart rate,
such situations is usually by high-flow face mask (HFFM). Yet, this blood pressure, respiratory rate, comfort, and tolerance.
may be uncomfortable for some patients. A recent advance in Results
oxygen delivery technology is high flow nasal prongs (HFNP). Patients in both protocols were comparable in terms of age, demo-
There are no randomised trials comparing these two modes. graphic, and physiologic variables including arterial blood gas,