Gastroenterology in intensive care
Intensive care exam revision on gastroenterology for medical student finals, PLAB exams and MRCP PACES
Gastrointestinal (GI) illnesses can either be the cause for admission to ICU or they can occur as a result of critical illness. The gastrointestinal tract may “fail” whilst on ICU. Click on the plus symbols below to expand each section:
Gastrointestinal failure can manifest in several ways:
- Delayed gastric emptying
- Failure to absorb feed
- Ileus and pseudo-obstruction
- Stress Ulcerartion
- GI ischaemia
- Liver dysfunction
It is important to try and protect against as many of the features of GI failure as possible and to monitor patients for it as closely as possible. Stress ulceration should be avoided with PPI prophylaxis and NG feeding should be instigated early under dietician advice. Prokinetics such as metoclopramide or eryththromycin can be used to aid with gastric emptying and electrolytes should be reviewed and corrected daily to prevent ileus.
Patients with diarrhoea should be assessed fully to exclude infection and stool cultures should be sent. Diarrhoea may be a result of overfeeding or feeding with an electrolyte composition not suitable for that patient. However the ICU physician must be alert to more sinister causes of diarrhoea such as ischaemic colitis and clostridium difficile colitis. Those with diarrhoea need to be resuscitated with electrolytes and fluids and treated with antibiotics if appropriate. It is important to ensure nursing staff are equipped to cope with turning and cleaning the patient with diarrhoea as severe diarrhoea can exacerbate existing pressure ulceration and cause local infections.
This may present with diarrhoea, rising lactate and abdominal pain (if conscious). A CT scan may be helpful in the diagnosis. Patients may have a previous history of vascular disease or have a history of atrial fibrillation. Surgical advice should be sought urgently as treatment is resection of the ischaemic bowel.
Gastrointerstinal (GI) haemorrhage
One of the commonest GI reasons for ICU admission is upper gastrointestinal haemorrhage. Patients with upper GI bleeds can haemorrhage profusely and often need level 2 or even level 3 care to manage this. Those with alcoholic liver disease and upper GI haemorrhage are even more likely to require admission to ICU as the haemorrhage may cause encephalopathy.
Causes of GI haemorrhage include:
- Duodenal ulceration
- Gastric erosions and ulcers
- Oesophageal varices
- Portal hypertension and gastric varices
- Aortoenteric fistulae
- AV malformations
Patients with GI bleeds should be resuscitated with IV fluids and blood through large bore access. FFP and platelets should also be considered in major haemorrhage and you may need to activate your trust’s major haemorrhage protocol. Ensure clotting, full blood count, group and save and electrolyte samples have all been sent to the lab urgently.
On ICU, resuscitation can be guided by invasive CVP and arterial line monitoring. Definitive treatment will always be required and when the patient is stable enough an OGD should be performed. It is always important to inform the gastroenterology team early that there is a patient with an upper GI bleed so they can prioritise the OGD. Patients who are actively having haematemesis are likely to need intubation for airway protection during the procedure. Other options for definitive treatment of upper GI bleeds include embolisation under radiological guidance or surgical removal of the actively bleeding area. However endoscopy is usually the first step.
Variceal bleeding can be profuse and is associated with a high mortality. If bleeding cannot be controlled insertion of a Sengstaken-Blakemore tube can be attempted to compress the varices at the gastric fundus. Vasopressin should be administered if there are no contraindications. OGD is needed once bleeding is controlled so banding of the varices can occur. If all of these procedures fail a Trans-hepatic Intravenous Porto-systemic Shunt (TIPSS) can be considered.
Decompensated chronic liver disease
Patients with chronic liver disease may decompensate for a variety of reasons e.g. alcohol binge, sepsis, progression of disease, high protein diet and constipation etc. These patients require level 2 or level 3 support for several reasons:
- Encephalopathy may result in a low GCS and they may require airway protection
- Encephalopathy may result in combative and aggressive behaviour that requires sedation and higher level nursing
- Hypotension and 3rd space fluid loss may result in the need for inotropes and higher level monitoring
- Ascites can lead to severe sepsis requiring higher level monitoring and inotropic support
- Ascites can cause an intra-abdominal compartment syndrome which can lead to renal hypo-perfusion and patients may require treatment for renal failure.
- Hepatic failure can lead to hypoglycaemia which needs prompt detection and treatment
It is important that prior to referring a patient with decompensated chronic liver disease to ICU, that you carefully consider whether the patient is appropriate for higher level care. This often depends on the patient’s underlying cause for decompensation and whether this is reversible. It also depends on the severity of their liver disease and if they are a candidate for transplant. These decisions are complex and should be made with the consultant who knows the patient.
Many patients are admitted “electively” to ICU following major surgery. Undergoing a laparotomy can greatly alter a patient’s physiology and sometimes despite optimal resuscitation during theatre by an anaesthetist patients may still need admission to ICU for 24-48 hours. This is especially the in emergency laparotomy. A short stay on ICU can optimise fluid management, treatment of sepsis and allow restoration of normothermia. In patients undergoing elective laparotomies they are often pre-assessed as to whether they will need ICU post operatively. These patients often have multiple co-morbidities and a stay on ICU is part of the enhanced recovery pathway.
Other GI conditions that require ICU admission are biliary sepsis, acute pancreatitis, intra-abdominal sepsis and acute fulminant liver failure (e.g. secondary to drugs). These conditions may all require higher level monitoring, inotropic support and in the case of fulminant liver failure patients need incredibly close monitoring of LFTs, clotting and prompt ICU transfer to a liver unit as mortality is so high and transplant may be the only option.