II. ScvO2 as a helpful parameter during the weaning phase

II. ScvO2 as a helpful parameter during the weaning phase
Background:
- 37 year old male patient
- No relevant previous medical history
- Reason for admission: high fever, cough, shortness of breath
- Diagnosis: multiple organ failure caused by septic shock (streptococcal toxic shock syndrome)
Admission to ICU:
- Admission to ICU with septic multiple organ failure caused by haemolysis streptococcus type A
sepsis with need for high catecholamine dose. Additional histological findings confirmed
myocarditis and cholangitis.
- Consequently developed reduced cardiac pump function along with a progressive deterioration in
respiratory function caused by severe capillary leak. Two days after admission the patient required
intubation and mechanical ventilation
- On day 14 patient was able to be extubated with stable hemodynamics and adequate respiration.
- In spite of further inhalation therapy and short-term non invasive ventilation (CPAP) however,
progressive respiratory deterioration again developed.
- On day 20 patient had to be re-intubated because of pronounced pulmonary edema on chest X-ray.
Re-stabilized with analgesia and sedation and controlled mechanical ventilation.
- Prior to re-extubation on day 27 the CeVOX was installed to monitor the continuous central venous
oxygenation (ScvO2) throughout the weaning phase.
After extubation a new respiratory insufficiency developed which was highlighted by a decrease in
continuous ScvO2 to below 70% (see graph). The decrease in ScvO2 was apparent earlier than the
decrease in arterial oxygenation from 99% to 84% (see graph).
After the initiation of non-invasive ventilation (BiPAP) the respiratory situation improved initially (indicated by
the increased ScvO2). However, shortly afterwards respiratory exhaustion developed (visible by an obvious
decrease in ScvO2 to 55%) necessitating in a stepwise increase in FiO2. The progression of the ScvO2 on
this stage (with values mostly below 50%) reflects a generally inadequate oxygen supply, whereas
increasing the FiO2 resulted in a short-term increase in ScvO2.
After re-intubation a persistent improvement in the general oxygenation was observable, demonstrated by
the stable ScvO2 of between 60% and 65%.

Conclusion:
The respiratory exhaustion post extubation because of increased work of breathing and worsening oxygen
absorption was reliably reflected by the CeVOX ScvO2. Initiating non-invasive ventilation with increased
FiO2 was immediately accompanied by an increase in ScvO2. Only after re-intubation could a persistent
stabilization in ScvO2 be ensured (see graph).
In this case report the continuous measurement of ScvO2 reflected the repeated changes between
respiratory exhaustion and temporary recovery.
The respiratory deterioration that occurred post extubation was recognized a lot earlier by the continuous
measurement of ScvO2 than by the measurement of arterial saturation (see graph).
Graph:
SaO2 99%
Trend of ScvO2
SaO2 84%
Stepwise increase in FiO2
because of respiratory
exhaustion