Monitors in the ICU

The intensity of the care provided in ICU requires many monitoring devices. Patients in the ICU generally have many wires attached to them for various types of monitoring.

Monitors have alarms that notify members of the care team when a measurement is detected that is out of acceptable range. The constant alarming of these monitors can be frightening to patients and their families. It is important to remember that this highly sophisticated equipment is designed to provide the best possible care.

Some of the monitoring equipment seen in the ICU includes the following:

  • Cardiac or heart monitors: Cardiac monitors are used to monitor the electrical activity of the heart. The monitor looks like a computer screen with lines, or tracings, moving across the screen. The monitor has electrodes that are attached to the patient's chest with sticky pads.
  • Pulse oximeter: A pulse oximeter allows the critical care team to monitor the saturation of oxygen in the blood. It looks like a clothespin and is attached to a patient's finger, or it may be smaller and clipped onto the earlobe.
  • Swan-Ganz catheter: A Swan-Ganz, or pulmonary artery catheter, is used to measure the amount of fluid filling the heart as well as to determine how the heart is functioning. It is inserted through the large vessels of the neck or upper chest and threaded into the heart.
  • Arterial lines (a-lines): Arterial lines are used for continuous monitoring of blood pressure. Catheters are inserted into an artery, usually in the wrist or, less often, in the bend of the elbow (should not be the brachial artery) or groin. Arterial lines produce a tracing on a monitor that is similar to that of a heart monitor but with a different wave form. Arterial lines can also be used for drawing blood thus eliminating the need for repeated venipuntures (a surgical puncture of a vein for withdrawing blood).

Tubes & Catheters in the ICU

Central venous catheter (CVC): This type of catheter is a soft, pliable tube that is inserted into a large vessel (vein) in the neck (internal jugular vein), in the upper chest (subclavian vein), or in the groin area (femoral vein). Patients are sedated and receive a local anesthetic prior to insertion. Sutures secure the CVC, which can be left in place for days or weeks. CVCs are used:

  • to administer frequent or continuous medication;
  • to administer large multiple IV products that do not fit in one line; and
  • to measure central venous pressure (the amount of fluid in the vessels).

CVCs carry some risk of bloodstream infection and thrombosis (tenderness and abnormal fluid collection in tissues, impaired movement, and engorged veins).

Intravenous (IV): An IV is a are plastic catheter (tube) that is inserted into the veins (peripheral IV) or a larger size catheter inserted into the larger veins of the neck. Fluids, medications, nutrition preparations, and blood products are administered through IV catheters. Patients in ICU often have multiple IVs.

Chest tubes: Chest tubes are inserted through the chest wall into the space around the lung to drain fluid or air that has accumulated and prevent the lung from being able to expand.

Urinary catheter: Urinary catheters, often referred to as Foley catheters, are inserted through the urethra into the bladder. Once in the bladder the catheter is kept in place by a balloon, which is inflated, at the end of the catheter. Urinary catheters continuously drain the bladder and allow for accurate measurement of urinary output, which is extremely important in fluid management and in assessing kidney function.

Endotracheal tubes:Endotracheal tubes are used when mechanical ventilation is necessary. The soft plastic tube is inserted either through the nose or through the mouth, between the vocal cords and into the trachea. A small soft balloon at the end of the tube in the trachea is inflated to prevent air from escaping, thus allowing adequate ventilation by the respirator. The process of having the ET tube inserted is referred to as intubation.

Patients who are intubated are unable to speak, so it is important to try to ask yes or no questions to which they can respond by shaking or nodding their head. Some patients may be able to communicate by writing. Most often patients who are intubated require sedation and may not be responsive at all.

Life Supportive Devices in the ICU

Ventilator: The ventilator, or respirator, is a breathing machine that helps patients breathe when they are too ill to breathe on their own. A patient is connected to the ventilator by an endotracheal tube (a flexible plastic tube that is inserted into the mouth and then down into the trachea).

It is often necessary for a patient to be sedated while on the ventilator, which may limit his or her ability to respond. This is necessary both for patient comfort and for the ventilator to be able to work effectively. As a patient's lungs recover, the amount of ventilator support is gradually decreased until it is felt a patient can breathe on his or her own.

Some patients need a ventilator to help them breathe for a prolonged period of time. If this occurs, a tracheostomy is often performed. This procedure involves making a small hole in the neck, just below the vocal cord. A small tube is inserted into the hole and connected to the ventilator. It is performed either in the ICU or in the operating room.

When the patient no longer requires the ventilator, the tube is removed and the hole in the neck eventually heals. A tracheostomy is comfortable for the patient and prevents damage to the trachea.

Nutrition: Nutrition is very important for the critically ill. Even though the ICU patient is immobile and does not appear to require "food" for energy, the illness or injury that has required the patient to be in the ICU increases the patient's basal metabolic rate(a measure of the rate of metabolism). Adequate nutrition is essential to the healing process.

Nutritional solutions can be administered through feeding tubes inserted through either the nose or the mouth into the stomach or through central venous catheters. The stomach route is preferred, as long as the patient's GI tract is working and able to tolerate feeding. Special nutritional preparations are available to provide the nutritional needs of the critically ill. The nutritional needs are calculated and monitored closely by the nutritionist on the critical care team and are adjusted accordingly.

Informed Consent

Prior to initiating any procedure in the ICU, physicians must secure informed consent (permission) from the patient. Except in emergency situations, physicians obtain consent directly from patients.

If a patient cannot give consent, the physician seeks permission from an individual with durable power of attorney for health care. Durable power of attorney is a legal document that grants authority to make another person's health care decisions when that person is unable to make those decisions. If this is not available, a close family member can grant consent.

In some cases, patients have specific wishes that have been communicated in legal documents, such as the following:

  • Advance directive: Advance directive contains instructions regarding health care decisions, especially in the case of incapacitation. It can include durable power of attorney and living wills.
  • Do not resuscitate (DNR) order: A DNR is a patient's instructions not to re-start a failed heartbeat or respiration. It does not mean that the patient will not be treated with medications. Patients who are DNR may still receive antibiotics and sedation or medications for pain. Do not resuscitate allows for a patient to die naturally if his or her respiratory or cardiac systems stop working.

If an advance directive or DNR order does not exist, the family can communicate the patient's preferences to the critical care team.

Publication Review By: Dominic J. Valentino III, D.O., F.C.C.P.

Published: 02 Jun 2000

Last Modified: 02 Sep 2015