Aspiration at anaesthetic

Posted in aspiration, anaesthesia; Posted 11 years ago

A colleague shared his recent experience with a rather unusual and difficult case last week during the Australian College Scientific Meeting.

A sixty-something year old patient deteriorated a few hours after a straight forward laparoscopic hysterectomy. She had to be admitted to ICU, developed ARDS and acute pulmonary failure, went on to CPAP, but survived. He is not aware about the reason for the patient having a rough time. What happened?

When I trained in Perth (many moons ago), I came across the following situation. I patients booked for elective surgery aspirated during induction. I was called into the operating room where the anaesthetic registrar informed me about the aspiration of gastric contents. He noted that the aspiration has been dealt with, there was no problem, the pO2 was stable and he thought we should proceed. He said: “I just wanted to let you know …”.

As a then trainee I have not come across this situation before. I saw my boss, told him the story and he decided: “The operation is off”. I went back to the anaesthetist, asked him to wake the patient up – operation is off. He was rather unhappy about that and asked for an explanation. I went back to my boss who told me that patients who aspirate may not do well in their recovery and we don’t want to put another burden on them by giving them an operation.

The patient went to the ward, deteriorated, needed to be admitted to ICU, had a hard time for 2 days and survived. We did the original operation three weeks later without problems.

Guess what! A couple of months later, the same thing happened again. Different anaesthetist, same situation. She said “patient aspirated minimal amounts – no problems to expect – you can go ahead – I just let you know”. 

By then I was obviously smarter. I called the operation off, just checked with my boss who agreed. There was significant kerfuffle because the anaesthetist felt we should proceed with surgery as planned.

The patient went to the ward, deteriorated, had to be admitted to ICU, had a hard and difficult time for two days, recovered and had surgery as originally planned, just three weeks later. Like Groundhog Day.

When my friend told me his story at the conference last week, my experience from 10 years ago came to mind again. The postoperative course almost matched. Hence, I checked out the textbooks on this matter – and this is what they say:

Acidic aspiration into the lungs causes chemical pneumonitis and is independent of bacterial load. Mendelson described it first in 1946 on patients for obstetrics anaesthesia. The original series included 61 patients. All patients developed ARDS within a few hours from surgery but all recovered promptly and survived.

Subsequent studies reported far worse outcomes. These authors reported on a  retrospective series on 50 patients. 12% died instantly. Some 60% of patients did well. The remainder did well initially but then deteriorated. That is the course that I observed with my 2 patients from Perth and this is what I suspect my colleague ran into the other day. These patients deteriorated possibly because of bacterial overgrowth.

A possible explanation for the differences in outcomes between the 2 groups described above? Obstetrics patients are usually young, fit and healthy.

What will I do if I come across an aspiration at induction of anaesthesia?

1. I delay any elective surgery. I would only proceed with surgery for life-threatening conditions or if you have to proceed with a caesarean section.
2. Transfer the patient to ICU and watch.
3. Start broad-spectrum i.v. antibiotics
4. Keep the patients in hospital for at least 2 or 3 days until you are certain she is doing fine
5. Organise for to patient to see a speech pathologist to see if there are any other factors contributing to aspiration.

Have you come across suspected or witnessed aspiration at anaesthesia? Pls comment below. 

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