• SOM 4th Yr Curriculum

• CLERKSHIP INFORMATION
• Introduction / Goals and Objectives
• Rotations
  • HMC
  • UWMC
  • VAMC
• Seminars
• Faculty Only
• PULMONARY EDUCATION
• Pulmonary Med Library
• Arterial Blood Gases
• Cardiopulmonary Exercise Testing
• Mechanical Ventilation
• Pulmonary Function Testing
• Pleural Effusion
• Radiology

Mechanical Ventilation

Case 8 Answers

At 11:00PM, you are called to the bedside of a 55 year-old man who was intubated one day prior for airway protection during a large upper gastrointestinal hemorrhage due to esophageal varices. He has self-extubated and is lying with the endotracheal tube in his hand. At the time this happened, he had been on an F_IO₂ of 0.4 and a PEEP of 5 cm H₂O. His PaO₂ earlier in the day was 100 mm Hg. The team had been planning to do a spontaneous breathing trial in the morning. At present, his oxygen saturation is 94% on 6L oxygen by nasal cannula. The nurse wants to know if you want to re-intubate him.

What should you do?

This patient has experienced what is referred to as an “unplanned extubation.” There are two ways in which this can occur: In an “accidental” extubation, the endotracheal tube becomes dislodged by patient movement, transferring the patient between beds or other activities at the bedside. In “self-extubation” the patient pulls the endotracheal tube out by themselves.

In cases of unplanned extubation, it is not always necessary to reintubate the patient. The limited data available on this clinical situation suggests that when unplanned extubation occurs in a patient who the team was already considering separating from the ventilator (eg. planning for spontaneous breathing trials), the majority of these patients remain off the ventilator. If they initially appear stable following the unplanned extubation, you can observe them and not automatically reintubate them. The likelihood of them remaining off the ventilator is increased if their P/F ratio is > 200, their minute ventilation needs were low prior to the event and it was a self-extubation. In situations in which you were not considering separating the patient from the ventilator because they were too sick, or oxygen requirements or minute ventilation needs are high, the overwhelming majority of these patients require reintubation. They should not be observed and should, instead, be reintubated immediately.

In this particular case, the team had been considering doing a spontaneous breathing trial and the patient had low oxygen requirements. He is someone you could observe for a period of time rather than reintubating immediately. If you were concerned about on-going gastrointestinal bleeding and aspiration risk, however, you might need to reintubate him for that reason.

You decide not to reintubate the patient because his clinical status appears stable. Four hours later, you are called back to the bedside because the patient is laboring to breathe and his oxygen saturation has fallen into the upper 80% range on a venturi mask set with an F_IO₂ of 0.5. You obtain an ABG and it shows pH 7.30, PCO₂ 47, PO₂ 60 and bicarbonate 25.

Should you reintubate the patient or can you give him a trial of non-invasive ventilation?

This patient is “failing” extubation, as he has a rising PCO₂ and declining PO₂ within only 4 hours of his unplanned extubation. He should not be given a trial of non-invasive ventilation and should, instead, be reintubated. The data on extubation failure demonstrates that patients who fail extubation and receive a trial of non-invasive ventilation end up being reintubated at the same rate as those who receive standard care (early reintubation). All the non-invasive ventilation appears to do in these cases is delay reintubation to a point when the patient may, in fact, be sicker and the intubation process may carry more risk.

Case Index>>

Top of Page