Why sedated in icu

This increases the difficulty of achieving benefit from analgesic and sedative medications without harm from their associated complications. Drug accumulation from continuous infusions, redistribution, and tachyphylaxis also confound the utilization of sedatives, necessitating techniques to prevent systemic drug accumulation. Thus, to develop the best treatment strategy for analgesia and sedation, the specific medical condition necessitating treatment must be recognized and continually reevaluated.

Thereafter, objective routine assessments of pain, arousal, and acute brain dysfunction eg, delirium and coma are necessary to guide the adjustment of goal-directed therapeutic targets that change with the medical condition of the patient. Mechanical ventilation, invasive monitoring, preexisting diseases, nursing interventions, and medical procedures are only a few sources of discomfort commonly experienced in the ICU.

Insufficient pain relief can contribute to increased stress response, deficient sleep, disorientation, anxiety, delirium, and PTSD. Routine monitoring that includes intensity, quality, and location of the pain has been associated with lower analgesic and sedative utilization and decreased time on mechanical ventilation. Nonpharmacologic methods for managing pain in the ICU include patient repositioning, lumbar support, injury stabilization, removal of noxious or irritating stimuli, and application of heat or cold.

When nonpharmacologic methods are insufficient to control pain, provision of analgesia by regional or systemic therapy is indicated. Regional analgesic therapies provide analgesia for specific areas of the body without the systemic effects of intravenous analgesics.

Blockade of an individual nerve or nerve plexus may provide relief of pain localized to one extremity, and this targeted action can be prolonged by placement of a peripheral nerve catheter. Multiple studies examining epidural analgesia have shown reduced morbidity after major surgery, including improved pulmonary and intestinal function, 13 but epidural analgesia has not been shown to reduce mortality or length of stay despite improving pulmonary function in a meta-analysis of traumatic rib fracture patients, a commonly prescribed indication.

While these procedures are useful adjuncts to decrease exposure to side effects of potent analgesics, they are not without risk. Systemic analgesics should be administered as part of a goal-directed analgesia and sedation protocol. Systemic therapies include acetaminophen and nonsteroidal anti-inflammatory drugs such as ketorolac, but the most commonly used analgesics in the ICU are opioids secondary to their analgesic and sedative properties.

Although they are the mainstay of analgesia in the ICU, opioids have a number of adverse effects. Respiratory depression is commonly seen and often enhanced by co-administration of additional sedative agents. Hypotension may result from decreased sympathetic tone or vasodilation from histamine release.

Other side effects include decreased gastrointestinal motility, pruritus, flushing, urinary retention, and delirium. Consequently, nonopioid analgesics should be considered for treatment of low acuity pain or as adjuncts to decrease opioid exposure to preserve mental status and pulmonary function while reducing additional side effects.

Morphine, hydromorphone, fentanyl, and remifentanil are frequently used opioids in the ICU. Morphine and hydromorphone are most often utilized as intermittent intravenous IV injections. Morphine is often given in doses of 2—5 mg IV every 5—15 minutes until the pain is controlled, followed by similar doses on a scheduled basis every 2—4 hours.

Morphine is characterized by hepatic metabolism and renal excretion with intermediate volume of distribution. Therefore, its effects can be prolonged in patients with renal or hepatic impairment or obesity. Unlike morphine, hydromorphone does not have active metabolites; thus, it has an improved safety profile in patients with renal disease. Fentanyl is a synthetic opioid with a rapid onset 5—15 minutes and a short duration of action 30—60 minutes.

It is easily titrateable as a continuous infusion secondary to its short half-life. It has a large volume of distribution secondary to its lipophilicity, while its clearance correlates most closely with pharmacokinetic mass similar to lean body mass ; therefore, significant drug accumulation and a prolonged context sensitive half-life can occur with prolonged infusions. Remifentanil, a derivative of fentanyl, is unique as an opioid secondary to its metabolism by nonspecific blood and tissue esterases.

It is utilized primarily as an infusion 0. Dosing regimens for the infusion should be based on ideal body weight or lean body mass, 17 and hypotension and bradycardia are the most common side effects seen with remifentanil administration. Importantly and secondary to its ultra-short half-life, supplemental analgesic medication is required at the conclusion of a remifentanil infusion.

The selection of an opioid for systemic analgesia has traditionally depended on the pharmacology of the specific opioid and the likely required duration. Unfortunately, few comparative trials have been performed in critically ill patients.

Remifentanil provided better outcomes than morphine with regards to time at optimal arousal level, necessity of supplemental sedation, duration of mechanical ventilation, and extubation time in one randomized double blind study. With regards to acute brain dysfunction outcomes, the literature is inconsistent. In a prospective cohort study of elderly hip fracture patients, the patients who received higher morphine equivalents per day were less likely to develop delirium than patients who received less analgesic medications.

Sedative medications are commonly prescribed within the ICU environment primarily for the treatment of agitation and anxiety, which themselves may be caused by many different conditions eg, dyspnea, delirium, mechanical ventilation, lack of sleep, and untreated pain. The appropriate use of sedatives can facilitate patient care and contribute to patient safety; however, their use is associated with both short- and long-term negative patient outcomes, including prolonged mechanical ventilation and cognitive dysfunction.

There are many ICU arousal scales which are used to provide goal directed therapy individualized to the patient. It is important to recognize that the arousal scales are not applicable when the patient is being administered neuromuscular blocking drugs, and consideration should be given to the use of the Bispectral Index monitor in those instances.

Delirium is an acute fluctuating change in mental status characterized by inattention and altered levels of consciousness that is now considered to be a presentation of brain organ dysfunction. Sedation protocols are commonplace within ICU environments and provide a structured framework that guides sedative administration and monitoring.

Their use alone has been associated with significantly improved patient outcomes. Key elements of sedation protocols should include arousal monitoring instruments, sedative dosing instructions, spontaneous awakening trials that are linked to spontaneous breathing trials, and early mobilization therapy. Spontaneous awakening trials daily interruption of sedation have been shown to reduce duration of mechanical ventilation, decrease ICU length of stay, and decrease the incidence of PTSD.

Despite numerous studies demonstrating that deep sedation is not required in the majority of ICU patients and that lighter sedation goals improve outcomes, many providers have been hesitant to implement these techniques due to concern for patient safety and the belief that patients would be more likely to develop long-term psychological issues without deep sedation during their ICU stay.

The ABC trial, however, showed no difference in the rate of re-intubation between the control and intervention groups, and studies incorporating daily wake up trials have shown no increase in the incidence of PTSD. It is advisable that each ICU develop a local sedation protocol that takes into account current research, patient characteristics, and local evidence.

Prior to implementation, all staff involved in administering the protocol should be trained in its application and opportunity given for modification when necessary. Providers should recognize that sedative medications are considered part of a multimodal approach to ensuring patient comfort and safety. Important aspects also include providing analgesia, maintenance of a normal day—night cycle, patient positioning, and appropriate mechanical ventilation strategies.

It must also be appreciated that sedatives should only be considered once pain has been adequately treated — the concept of analgesia-based sedation or analgosedation. Once analgesia has been obtained, sedative medications can be utilized to reach arousal targets when needed. An empiric protocol Figure 1 for the management of pain, sedation, and delirium is provided as a reference. With permission from www.

The ideal sedative will be inexpensive, have minimal respiratory depression, elimination independent of organ function, short context sensitive half-life, and no active metabolites.

Unfortunately, none of the commonly used sedatives fulfill all these criteria, and practitioners should be aware of their limitations when choosing a sedative medication. The most common sedative medications used within the ICU are propofol, dexmedetomidine, and benzodiazepines, with other agents such as clonidine, ketamine, volatile anesthetics, and neuromuscular blockers used as adjunct therapies.

Importantly, the duration of sedative medication administration has been shown to correlate with the duration of mechanical ventilation, and the consistent theme throughout many sedation studies is that efforts should be made to minimize the total dose of sedative by using the minimum effective dose, daily interruption of sedation, and infusions for the shortest time required. It has proven utility as a sedating agent in the ICU due to its rapid onset 1—2 minutes and short duration of action 2—8 minutes.

Its volume of distribution is large with a short distribution half-life. Emergence is related to redistribution and not metabolic clearance when used as bolus or low-dose infusion, which can be advantageous in patients with renal or hepatic dysfunction. When propofol is used as a long-term infusion and saturation of peripheral tissues occurs, emergence is more related to metabolic clearance.

Propofol side effects include hypotension due to vasodilation and myocardial depression, respiratory depression, and hypertriglyceridemia. The hypertriglyceridemia may either be due to the intralipid carrier or altered hepatic lipid metabolism, which can be seen with the propofol infusion syndrome PRIS.

When high dosage or prolonged infusions are being used, it is recommended to regularly monitor serum pH, lactate, creatinine kinase, triglyceride levels, and electrocardiograms Brugada-type changes. Dexmedetomidine is an alpha-2 receptor agonist whose site of action includes presynaptic neurons in the locus ceruleus and spinal cord. Article Navigation. Close mobile search navigation Article Navigation. Volume 8. This article was originally published in.

Article Contents Principles of sedation. Monitoring sedation. Non-pharmacological methods of aiding sedation. Pharmacological management. Delivery of sedation. Sedation holidays. Sleep on the ICU. Accumulation of sedatives. Sedation protocols. Sedation in the intensive care unit. Specialist Registrar in Anaesthesia. Oxford Academic.

Consultant Anaesthetist. Select Format Select format. Principles of sedation Sedation allows the depression of patients' awareness of the environment and reduction of their response to external stimulation. Monitoring sedation Why is it important? Scoring systems Clinical scoring systems There are many clinical scoring systems in use within the UK; examples include the Ramsay, Addenbrookes, and the Bloomsbury scales Table 1. Table 1 The Bloomsbury sedation scale. Sedation score.

Open in new tab. Table 2 Sedative agents commonly used in ICU. Class of drug. Table 3 Properties of opioids commonly used in ICU. Accumulation in renal failure. Excreted in the urine Yes Fentanyl 13 In the liver to norfentanyl, which is rendered inactive by hydroxylation. Inactive metabolites are excreted in the urine No Alfentanil 6 In the liver by hydroxylation to noralfentanil, which is rendered inactive by conjugation.

Excreted in the urine. Elimination delayed when given concurrently with midazolam as both metabolized by same enzyme No Remifentanil 40 Broken down by non-specific plasma and tissue esterases. Elimination half-life of 3—10 min independent of duration of infusion No.

Open in new tab Download slide. An example of sedation protocol in clinical use. Bispectral index compared to Ramsay score for sedation monitoring in intensive care units. Google Scholar PubMed. Prolonged sedation of critically ill patients with midazolam or propofol: impact on weaning and costs. Google Scholar Crossref. Search ADS. Economic evaluation of propofol for sedation of patients admitted to intensive care units. Reliability of in vivo mixed venous oximetry during experimental hypertriglyceridemia.

Clinical practice guidelines for the sustained use of sedatives and analgesics in the critically ill adult: Sedation and Analgesia Task Force of the American College of Critical Care Medicine.

Remifentanil; a review of its analgesic and sedative use in the intensive care unit. Remifentanil in the intensive care unit: tolerance and acute withdrawal syndrome after prolonged sedation. Sedative, analgesic and cognitive effects of clonidine infusions in humans.

While other scales, such as the one of Cook and Palma, 70 have a greater number of items, allowing for evaluation of an increased amount of clinical information, they have not been validated.

These aspects of scoring systems lead to concern regarding the reproducibility and validity of results and difficulty in interpretation of results across studies. Additional difficulty arises when different definitions of ideal level of sedation are used; for example, some studies required Ramsay level 3, while others used levels 2 to 4, 3 to 5, 2 to 5, or 5.

This review highlights the need for a reliable and valid sedation scoring system to improve the interpretability of future studies. Blinding both patients and assessors to treatment is of greatest importance when subjective outcomes are used. In the trials reviewed, those assessing quality of sedation were frequently aware of the sedative agent the patients were receiving.

Knowing which agent a patient is receiving can introduce the potential for bias in interpretation of the outcome of interest. While interpretation of quality of sedation was the most subjective outcome assessed, time to extubation and length of ICU sedation can similarly be influenced by knowing which sedative agent was received. It is possible that blinding of assessors had been performed in some studies and not reported; however, the importance of double-blinding has become so well recognized during the past decade that most investigators will report its use if it was done.

All cointerventions, including anesthesia if applicable , use of analgesics other than those being directly studied and neuromuscular blockers, and approach to weaning from mechanical ventilation, should be standardized or at least reported. These measures will help reduce bias in interpretation of end points, such as quality of sedation, time to extubation, and length of ventilation and ICU stay. These processes were not followed in many of the trials reviewed.

It is useful to consider how, with time, secular changes in practice can influence the interpretation of study results. For example, the approach to cardiac surgery patients has evolved during the past decade from a common practice of keeping patients intubated and sedated overnight to a more aggressive approach of allowing patients to awaken and be extubated as soon as possible, referred to as fast-tracking.

The lack of randomized trials for some of the sedative agents currently in use in ICUs raises the issue of considering observational studies to obtain the best evidence for such agents as haloperidol or diazepam.

However, the potential for bias increases appreciably when studies using historical or nonrandomized controls are considered. Given the widespread use of sedation for ICU patients, there is a dearth of rigorous, adequately powered randomized controlled trials comparing commonly used agents in this setting. More economic evaluations are warranted in this field, given the diverse purchasing costs of different agents and their variable and incompletely evaluated effect of economic outcomes, such as duration of mechanical ventilation and duration of ICU stay.

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Clin Intensive Care. Practice parameters for intravenous analgesia and sedation for adult patients in the intensive care unit: an executive summary.

Olsen HT, et al. Nonsedation or light sedation in critically ill, mechanically ventilated patients. The New England Journal of Medicine, In press. Mayo Clinic. This content does not have an English version. This content does not have an Arabic version.