An Overview of  Critical Care

Supportive Care

It is important not to forget that the intensive care patient is not just a series of diseased organs, but a human being with physical, psychological and spiritual needs. Admission to intensive care, for most of our patients is a time of great suffering, and it is essential that we minimize our patients’ distress. We can do this, primarily, by having the courage to identify futile states, before and after admission to ICU. If a patient has no prospect of survival, continuance of intensive care is prolongation of suffering rather than prolongation of life.

We must prevent suffering

We must address pain and discomfort in a pragmatic manner: there is a double whammy – we want our patients rousable, but not distressed. It would appear that the most effective method of sedating patients in critical care is to use infusions of ultra short acting agents (thus guaranteeing rapid wakening) -  propofol and remifentanyl. Unfortunately, the use of both of these agents is prohibitively expensive for all but a short time (44). No ideal sedation strategy has yet been developed and sedation protocols are frequently dictated by economics rather than efficacy (45).

It is important to realize that intensive care patients experience a lot of pain (emotional response to a noxious stimulus); they need pain killers, of which opoids are the most appropriate. Acetaminophen is grossly underused as a pain killer, and non steroidal anti inflammatory agents are often inappropriately avoided (because of fears of peptic ulcers and renal failure). Of the opioids used, the most commonly prescribed are fentanyl, morphine, hydormorphone and methodone. All tend to accumulate, and the short acting effect of fentanyl is generally misunderstood (long terminal elimination half life). Nonetheless, the latter has a significant advantage of not having active metabolites. Although morphine has some sedative properties (plus a multitude of side effects), fentanyl and hydromorphone are remarkably clean, and provide analgesia only. In responsive patients it is useful to record pain scores to facilitate titration of therapy.

The most commonly used sedative agents in ICU are benzodiazepines, midazolam and lorazepam (46). The former is short acting and given as infusions or intravenous boluses, the latter as q6 or q8 hourly boluses. Both tend to accumulate. As a sedation  regimen in intensive care, fentanyl  and midazolam represent a reasonable combination (at least until alfentalil and propofol become more cost effective). Note that both fentanyl and midazolam need to be discontinued well in advance of extubation, due to accumulation and active metabolites respectively. If the patient is to require a patient controlled analgesic (PCA) device, I would recommend morphine or hydromorphone, due to their more favorable pharmacokinetics.

A new agent, dexmedetomidine (dex), is currently being promoted. This is an alpha-1 agonist, the same class as clonidine (sometimes used for alcohol/drug withdrawl), with minimal hemodynamic or respiratory depressant effects (47).

Pain Scores

Glasgow Coma  Score

RamsaySedation Scale

Levels of sedation may be recorded using the Glasgow Coma Score (GCS) or the Ramsay Sedation Scale (48). This scale scores 1 (anxious/distressed) to 6 (comatose); most authorities agree that the optimal score is 3 (rousable to commands).

If one is confronted with a psychotic patient, haloperidol is the most effective sedative. The best regimen is to start with 2.5mg iv and double the dose every 5 minutes until the situation is under control.

Sleep deprivation is a major problem in ICU. Benzodiazepines sedate patients, but abolish REM sleep. For sleep assistance chloryl hydrate and antihistamines remain the agents of choice.

DVT Prophylaxis

Immobile patients are at risk for bed sores and deep venous thromboses (DVT). It is important that patients are frequently turned in the bed (water and air mattresses are very useful) and any skin breakdown is meticulously cared for. The use of graduated stockings, sequential compression devices (SCDs) and / or heparinoids is essential to prevent thrombosis and pulmonary embolism.

Stress Ulcer Prophylaxis

Traditional teaching remains that intensive care patients are at high risk for peptic ulceration due to stress. This is undoubtedly overstated. The use of prophylactic H2 antagonists or sucralfate remain a standard of care (49).

Do not allow the patient to lie flat

The early use of enteral feeding may attenuate the septic inflammatory response. The use of post-pyeloric feeding tubes may lead to better overall calorie intake, although the risk of aspiration with nasogastric feeding is probably over estimated (50). On the same line, there is compelling evidence that patients nursed in the semi recumbent position have a lower incidence of nosocomial pneumonia than patients nursed lying supine (51).

Nosocomial Pneumonia

Line Sepsis

Although the use of intravascular catheters is essential in intensive care, these can in themselves provide a source of infection. Due to low flow states, lines in the venous circulation (central catheters, pulmonary artery catheters) have a higher incidence of infection than those in the arterial side. There is no evidence that routine line changes reduces infection rates, and the routine rewiring of lines appears illogical (52). Nonetheless, a clear policy of line removal if suspicion of sepsis arises, is important.

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