How to use the Ramsay Score to assess the level of ICU Sedation

 

Michael A. E. Ramsay M.D.

 

 

Introduction

 

          Virtually every patient admitted into the intensive care unit (ICU) is administered sedation therapy. The precise control of the depth of sedation is often not well managed. Patients are frequently over or under-sedated with, as a result of this lack of control, an accompanying increase in morbidity, mortality and economic cost.

          Over 25 years ago, an attempt was initiated to bring the control of sedation level up to the same level of intense management as the control of hemodynamics, fluid and electrolyte balances, oxygen and metabolic parameters [1]. This concept has taken a long time to reach the critical care pathway of the majority of ICUs. However, economic issues and advances in pharmacology, have lead to a critical re-evaluation of sedation techniques, so that the goal of a heavily sedated or comatose patient for the maintenance of ventilator synchrony, is now changing to the goal, where possible, of a calm, co-operative, comfortable and communicative patient, who can interact with family members and medical staff. This change in practice pattern has resulted in shorter periods of time on mechanical ventilation support, leading to a shorter stay in the intensive care unit [2,3].

 

Sedation goals

 

            The effective management of pain, anxiety and sleep (hypnosis) are the major aims of a sedation therapy regimen. The ICU environment frequently lends itself to being an unpleasant experience for the critically ill patient. The patient is exposed to numerous ominous and frightening procedures that are a necessary part of the care process. In an effort to make this clinical arena a more humane place to be treated, sedation therapy is administered. The careful and precise control of sedation therapy may lead to better control of the patient requiring mechanical ventilation support, and reduce the requirement for the use of neuromuscular blocking agents.

          The desired result of a sedation regimen is to allow the patient to tolerate the physical environment, and the unpleasant procedures and therapies that are necessary in the ICU; to facilitate nursing care and management, and reduce both anxiety and stress, so that post-traumatic stress disorder does not occur after discharge from the unit. Patient safety is paramount, and the avoidance of self-extubation and inadvertent removal of catheters and other life dependency equipment is essential. Amnesia is probably another useful goal of sedation therapy, so that the patient has no recall of unpleasant events or surroundings. It has, however, been suggested that patients recovering from intensive care therapy, may have an unrealistic outlook on their recovery, if they have no recall on the severity of their illness [4].

The blunting of autonomic responses, reduced oxygen consumption and ventilator synchrony are other important goals of sedation therapy. The maintenance of a normal sleep pattern can help maintain psychological well-being, as well as preventing exhaustion and the loss of a desire to survive. Patient agitation is another common problem in the critical care unit, it may result from a specific cause such as hypoxia, under ventilation, metabolic derangement and other correctable entities that should be addressed first, but it may be the result of sleep deprivation, or pharmacological interactions, and require sedation to control [5-9].

Pain management

 

The effective management of pain is essential in the proper management of sedation, and results in improved patient satisfaction, a faster recovery with reduced complications [10]. This has to be the priority when assessing a patient's sedation requirements. Adequate analgesia may reduce the necessity for other sedative therapy. Nearly all patients in the ICU experience pain, whether it is the result of procedures performed on them, the disease process, catheters or tubes inserted into them, or because they are immobile and cannot shift position. If the patient is paralyzed or obtunded, they will have lost the ability to communicate the severe discomfort that they may be in, to the care team. The sequelae of severe untreated pain can be long lasting psychological effects on the patient, together with adverse haemodynamic changes. Tachycardia and hypertension, together with an increase in systemic vascular resistance, will cause an increase in myocardial oxygen consumption and demand, that may result in myocardial ischemia [10]. There may also be a deleterious effect on the immune system in an all ready compromized patient who is trying to combat a serious illness, but foremost it is inhumane not to adequately treat pain. The precise control of pain can reduce the need for deep sedation and reduce the necessity for muscle relaxants. The mainstay of analgesic therapy is still the opiates. Morphine or fentanyl are two of the narcotics most frequently administered in the ICU. They are effective pain relievers, but come with significant side effects, that may have a deleterious effect on the patient [11]. The balance between the adverse effects of the opioid analgesics, and the beneficial effect of analgesia, is a limiting factor in their use and the appropriate pain therapy delivered to these critically ill patients. These adverse effects include respiratory depression, deep sedation, narcotic bowel syndrome, pruritus, nausea, vomiting and a decreased ability to communicate. Nearly all the narcotics have active metabolites that will cause a prolongation of their effects when continually administered to patients with multi-organ system failure. This is the common profile for the intensive care patient; therefore there may be an insidious build up in the narcotic actions of these agents. Remifentanil, a relatively new, mu-receptor specific opiate that is rapidly metabolized by non-specific esterases into metabolites with very weak narcotic activity, may have a future role to play in the close control of pain in the critically ill patient [12].

Over sedation

 

          The results of over sedation in the mechanically ventilated patient are an increased time being ventilated,  an increased time in the intensive care unit, and an increased cost of care. The common effect of an increasing dose of most sedative agents is respiratory depression. This may facilitate ventilator synchrony, but will prolong the weaning process. In the extubated patient it may be associated with severe hypercarbia, hypoxia and respiratory arrest.

There is no sensitive monitor of respiratory depression in the extubated patient, who is receiving supplementary oxygen. Under these circumstances, the only parameters that correlate well with respiratory depression are respiratory pattern and level of consciousness. Respiratory rate and end-tidal carbon dioxide measured via a nasal cannula, are not reliable monitors of depressed respiration [13]. The pulse oximeter is a LATE detector of respiratory depression, when there is an increased concentration of inspired oxygen [14].

Under sedation

          The untoward effects of under sedation include an increased production of endogenous catecholamines, that results in an increase in blood pressure, heart rate and myocardial oxygen consumption. The patient may be at risk for self injury from the accidental removal of the endotracheal tube or vital catheters. The mental sequelae from being awake while painful, and terrifying procedures are performed on the patient can be the development of a post-traumatic stress disorder, that may require prolonged therapy after discharge [15]. The patientsf who are unresponsive because of the administration of  neuromuscular blocking drugs are most at risk [16].

Sleep deprivation is very common, and can result in the development of the typical ICU psychosis [17].

Controlled Sedation

          To prevent the adverse complications of poorly controlled sedation, sedation therapy should be administered in a careful and precise manner. The depth of sedation should be clearly defined and the infusion of sedative drug precisely targeted to this clinical endpoint. If the patient is sedated to an unrousable depth, then unless clinically contraindicated, they should be brought to a level where a neurological assessment can be made every 24 hours [18]. In his manner a cerebral insult will not go undetected.  By defining the sedation level and carefully controlling the sedation infusion to meet this endpoint, the dangers of over or under sedation are minimized. It will also provide for continuity of care, as all care-givers understand the required depth of sedation.

To be able to reach this goal the routine use of sedation scales is essential. The scoring system selected for use must be easily understood, used routinely and be part of the regular assessment of the ICU patient In fact sedation scoring systems should be in regular use where ever potent respiratory depressant drugs are being used.

Sedation Scoring Systems.

A sedation scoring system should be an integral component of any  sedation protocol. The four most validated scoring systems include: The Ramsay Sedation Scale; The Sedation Agitation Scale; The Motor Activity Assessment Scale and for the pediatric population: The Comfort Scale [19].

The Ramsay Sedation Scale

The Ramsay Sedation Scale (RSS, Table), was the first scale to be defined and was designed as a test of rousability. The RSS scores sedation at six different levels, according to how rousable the patient is. It is an intuitively obvious scale and therefore lends itself to universal use, not only in the ICU, but wherever sedative drugs or narcotics are given. It can be added to the pain score and be considered the sixth vital sign.

   Ramsay Sedation Scale

 

1   Patient is anxious and agitated or restless, or both

2   Patient is co-operative, oriented, and tranquil

3   Patient responds to commands only

4   Patient exhibits brisk response to light glabellar tap or loud auditory stimulus

5   Patient exhibits a sluggish response to light glabellar tap or loud auditory stimulus

6   Patient exhibits no response

 

The RSS defines the conscious state from a level 1: the patient is anxious, agitated or restless, through the continuum of sedation to a level 6: the patient is completely unresponsive. Therefore when an assessment is to be made, the first decision to be made is to note if the patient is awake. If the patient is awake: are they anxious, agitated or restless (RSS 1) or are they calm, co-operative and communicative (RSS 2)? If the patient is asleep then a test of reusability needs to be made. If the patient responds quickly to a voice command, this is a RSS 3. If the response is slow then the patient is assigned a level 4. If the patient does not respond a stronger stimulus is applied. A louder auditory stimulus or a glabellar (between the eyebrows) tap is enacted. A brisk response to this test of rousabilty places the patient at a RSS 4. A slow or sluggish response categorizes the patient to a RSS 5. No response at all places the patient at a level 6.

          The rousability stimulus was specifically designed not to be a painful  test and not to startle the patient. In fact it was planned that a sleeping patient would not be roused to a fully awakened state, so that the sleep pattern would not be disturbed.

A disadvantage of the RSS is that it relies on the ability of the patient to respond, therefore the patient who has received neuromuscular blocking drugs cannot be assessed in this manner. Also at a level 1 score, there is no further definition of the degree of agitation, and there are occasions when this may be important to record. The Sedation-Agitation Scale does take this into consideration [20]. At the deep end of the scale, a RSS 6, there is no further information as to whether the patient is in a light plane of general anesthesia or deep coma. This assessment can be made from monitoring the compressed spectral array signal from an electroencephalogram, A bispectral index score of 61.7 correlates well with a RSS of 6 [21].

Conclusion

Despite the ready availability of sedation scales over the last 25 years, a review of ICU practice reveals that many units still do not closely control the level of sedation in their critically ill patients. In those units where sedation scoring systems are used fewer than half the patients are at the prescribed level for more than 50% of the time. Therefore there is still an opportunity to educate the importance of the dynamics of assessment, re-assessment and adjustment in the rate of delivery of sedative. This dynamic is essential to avoid the complications associated with over and under sedation.

 

     

 

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