Pain Management Critically Ill Patients ASIPP 2004

Pain Management Critically Ill Patients:

Pain Management Critically Ill Patients Hosam Atef Lecturer Pain Management/Anesthesiology

Analgesia:

Analgesia

ICU Analgesia:

ICU Analgesia 30%-70% of patients are bothered by pain during their ICU stay 50% complain of moderate, severe, or excruciating pain Need to determine the etiology of pain, treat it, and eliminate potential barriers to adequate pain control

Potential Barriers to Effective Pain Management:

Potential Barriers to Effective Pain Management Fear of “addiction” Eliminate the word addiction from your vocabulary. Learn the meaning of physiological dependence, psychological dependence, tolerance, and “pseudo” addiction, and explain these to your patient.

Potential Barriers to Effective Pain Management:

Potential Barriers to Effective Pain Management Physical dependence: Exhibited when a drug has been abruptly withdrawn or reversed Psychological dependence: Chronic preoccupation with obtaining the substance of choice, misuse or overuse of the substance despite negative consequences

Potential Barriers to Effective Pain Management:

Potential Barriers to Effective Pain Management Tolerance: The need for a higher dose of medication because the lower dose has become ineffective A normal occurrence that develops after one has been taking medication for a long period of time “Pseudo” addiction: Results when a patient “overuses” medication because he/she is receiving pain relief and wants more relief

Potential Barriers to Effective Pain Management:

Potential Barriers to Effective Pain Management Fear of medication side effects and inability to treat them. If the the side effects are to opioids and are mild, treat them until the patient becomes tolerant.

Potential Barriers to Effective Pain Management:

Potential Barriers to Effective Pain Management Fear of repercussion from governmental organizations. Document, Document, Document Develop a treatment algorithm and stick to it. Know when to consult a specialist.

Assessment of Analgesia:

Assessment of Analgesia A variety of pain intensity scales exist to evaluate a patients level of pain and to judge the efficacy of the analgesic regimen Examples include Numerical Ranking Scale Visual Analogue Scale Adjective Rating Scale A score of 3 or less is the goal Direct communication with the patient is important

Assessment of Analgesia:

Assessment of Analgesia From: Marino. The ICU Book, 2 nd Ed. Lippincott Williams & Wilkins, 1998.

Assessment of Analgesia:

Assessment of Analgesia Unparalyzed patient with altered mental status: 0 Painful stimuli necessary to gain attention or solicit movement 1 No grimacing or guarding with spontaneous movement or repositioning 2 Grimacing or guarding with vigorous movement 3 Grimacing or guarding with slight movement, takes greater than 1 min for the patient to relax 4 Grimacing or guarding at rest; not able to relax despite rest Alert, Responsive Patient 0 Not applicable 1 No pain 2 Minimal to mild pain 3 Moderate pain 4 Severe pain

Methods of Analgesia: Nonopioids:

Methods of Analgesia: Nonopioids Ketorolac Only NSAID available in an IV/IM formulation Inhibits platelet function and can cause gastric mucosal damage Partly metabolized in the liver and excreted in the urine Elimination is prolonged in renal failure & old age Can be given in an infusion at 5 mg/hr

Methods of Analgesia: Opioids:

Methods of Analgesia: Opioids Used for analgesia and sedation The effective opioid dosage should be determined by patient response, not by the numerical values of the dosage MSO 4 and fentanyl most common Dilaudid is a viable alternative Meperidine should be avoided secondary to potential accumulation of its’ metabolite normeperidine which can cause seizures

Methods of Analgesia: Opioids:

Methods of Analgesia: Opioids From: Marino. The ICU Book, 2 nd Ed. Lippincott Williams & Wilkins, 1998.

Methods of Analgesia: PCA:

Methods of Analgesia: PCA Eliminates the variable absorption from the injection site. Bypasses the unavoidable delays that occur when an opioid is requested. Unique in that patients titrate their analgesic needs against sedation & other side effects of opioids. Appropriate for patients requiring >48 hours to recuperate. Not a “Set and Forget” technique.

Methods of Analgesia: PCA:

From: Rosenburg, Grande, Bernstein. Pain Management and Regional Anesthesia in Trauma . WB Saunders, 2000 Methods of Analgesia: PCA

Slide 17:

Methods of Analgesia: PCA

Methods of Analgesia: PCA:

Methods of Analgesia: PCA

Neuraxial Analgesia:

Neuraxial Analgesia Refers to the use of opioids and analgesic concentrations of local anesthetics to produce analgesia by either the intrathecal or epidural administration Neuraxial opioid analgesia (selective analgesia) is produced by modulation of of nociceptive transmission at the level of the spinal dorsal horn in the absence of sensory, motor, or sympathetic blockade Segmental analgesia is produced by the epidural administration of local anesthetics and opioids, in that the extent of analgesia spread is related to the segmental level of administration and the volume and concentration of local anesthetic or opioid administered

Methods of Analgesia: Epidurals:

Methods of Analgesia: Epidurals Epidural analgesia Able to produce analgesia in selective, but relatively large areas of the body by a single injection or continuous infusion Proximity of the spinal cord and spinal nerve roots allows for the use of different classes of analgesics with different sites and mechanisms of action and different side effect profiles Can also utilize a patient-controlled technique (PCEA)

Methods of Analgesia: Epidurals:

Methods of Analgesia: Epidurals Benefits of a continuous epidural or intercostal blocks: Avoidance of endotracheal intubation Earlier post-injury extubation Decreased ventilator dependence Shorter ICU and hospital stay Improved post-injury rehabilitation

Corresponding Vertebral Levels for Optimal Epidural Catheter Placement:

Corresponding Vertebral Levels for Optimal Epidural Catheter Placement C7-T2 for upper extremity surgery T4-8 for thoracic surgery T8-10 for upper abdominal surgery T10-12 for lower abdominal and transabdominal pelvic surgery L2-4 for lower extremity surgery

Methods of Analgesia: Epidurals:

Methods of Analgesia: Epidurals From: Marino. The ICU Book, 2 nd Ed. Lippincott Williams & Wilkins, 1998.

Methods of Analgesia: Regional Techniques:

Methods of Analgesia: Regional Techniques Techniques: Brachial, lumbar, sciatic infusion catheters Treat pain and improve blood supply Intercostal nerve blocks May need to be repeated Paravertebral blockade +/- infusion Unilateral injury, or epidural contraindicated or technically difficult Interpleural catheter Same as paravertebral block Can be used bilaterally

Sedation:

Sedation

Tenets of ICU Sedation:

Tenets of ICU Sedation Goals: Reduce anxiety Reduce fear Sedation must be tailored to each patient’s physiology and pathology Goal is a Ramsey 3 or a Riker 4 Most ICU’s use a combination of both

Ramsey Sedation Scale:

Ramsey Sedation Scale If Awake: Ramsey 1 Anxious, agitated, restless Ramsey 2 Cooperative, oriented, tranquil Ramsey 3 Responsive to commands only If Asleep: Ramsey 4 Brisk response to light glabellar tap or loud auditory stimulus Ramsey 5 Sluggish response to light glabellar tap or loud auditory stimulus Ramsey 6 No response to light glabellar tap or loud auditory stimulus

Riker Sedation-Agitation Scale:

Riker Sedation-Agitation Scale 7 - Dangerous agitation Pulling at ET tube, trying to remove catheters 6 - Very agitated Does not calm, despite repeat verbal reminding of limit 5 - Agitated Anxious or mildly agitated, calms down at request 4 - Calm and cooperative Calm, awakens easily, follows commands 3 - Sedated Difficult to arouse, but awakens to verbal stimuli 2 - Very sedated Arouses to physical stimuli, does not respond to commands 1 - Unarousable Minimal or no response to noxious stimuli

Medications for Sedation:

Medications for Sedation Benzodiazepines Midazolam Rapid onset and short duration of action Prolonged infusion can lead to tolerance of CNS effects Elimination minimally dependent on renal function Can cause respiratory depression and hypotension in high doses Potentiated by coadministration of opioids Lorazepam Minimal CV and respiratory depression Has inactive metabolites Associated with prolonged weaning after extubation

Medications for Sedation:

Medications for Sedation From: Marino. The ICU Book, 2 nd Ed. Lippincott Williams & Wilkins, 1998.

Medications for Sedation:

Medications for Sedation Barbiturates Infusion doses are subhypnotic Thiopental: 1-5 mg/min Methohexital: 0.5-2.5 mg/min Prolonged infusion of methohexital is associated with a more rapid recovery than thiopental because the clearance rate of methohexital is 3-4x’s higher, resulting in a shorter elimination half-life

Medications for Sedation:

Medications for Sedation Ketamine Low dose infusions (5-25 mcg/kg/min) effective for sedation in the ICU and for local or regional anesthetic procedures Significantly decreases the opioid analgesic requirement when used for ICU sedation Effective for burn care May need to pretreat with a benzodiazepine

Medications for Sedation:

Medications for Sedation Etomidate Has been used in the past for ICU sedation Essentially abandoned secondary to its effect on adrenocortical synthetic function

Medications for Sedation:

Medications for Sedation Propofol Rapid onset and very short duration of action Dose dependent respiratory depression, hypotension, and hyperlipidemia Upon discontinuation of infusion, faster time to weaning from mechanical ventilation than midazolam Elimination minimally dependent on hepatic function Tolerance may develop with prolonged infusions

Medications for Sedation:

Medications for Sedation Dexmedetomidine Selective alpha 2 agonist Analgesic properties Preserves respiratory function Does not potentiate opioid respiratory depression Site of action is locus coeruleus of the brain stem Central sympatholysis is the dominant CV action Transient hypertension occasionally seen upon initial administration Bradycardia has also been documented

Medications for Sedation:

Medications for Sedation Dexmedetomidine Infusion initiated with a loading dose of 1 mcg/kg over 10 minutes followed by an infusion between 0.2-0.7 mcg/kg/hr Must be diluted in 0.9% saline for infusion Infusion is limited to 24 hours!!

Task Force of the American College of Critical Care Medicine - 1995:

Task Force of the American College of Critical Care Medicine - 1995 Recommendations: Sedation Midazolam and propofol for short term (<24 hours) Lorazepam for long term Analgesia MSO 4 for most patients Fentanyl for hemodynamically unstable patients

Medications for Sedation: Infusion:

Medications for Sedation: Infusion From: Marino. The ICU Book, 2 nd Ed. Lippincott Williams & Wilkins, 1998.

Opioid and Sedative Effects on Vital Functions:

Opioid and Sedative Effects on Vital Functions

CV Effects of Opioids:

CV Effects of Opioids Minimal CV effects at normal analgetic doses Bradycardia and hypotension seen at higher doses Bradycardia caused by a specific stimulant effect on the central nuclei of the vagus nerve Hypotension secondary to peripheral vasodilation Meperidine, which is weakly atropinic, does not usually cause bradycardia

CNS Effects of Opioids:

CNS Effects of Opioids Can cause sedation in usual analgesic doses Usually do not produce amnesia in subhypnotic doses Can cause hypnosis in higher doses Dysphoria and agitation infrequent with normal analgesic doses Incidence higher with meperidine and codeine

Respiratory Effects of Opioids:

Respiratory Effects of Opioids Produce a dose-related respiratory depression of the ventilatory response to CO 2 by a direct effect on respiratory centers in the medulla At usual analgetic doses, opioids rarely cause clinically significant respiratory depression unless there is a pre-existing pathology or previous drug administration

GI Effects of Opioids:

GI Effects of Opioids Produce spasm of the smooth muscle in the GI tract Mechanism involves both CNS effects and peripheral actions on opioid receptors in the bowel Both bowels become hypertonic, peristalsis is diminished

CV Effects of Sedatives:

CV Effects of Sedatives From: Barash, Cullen, Stoelting. Clinical Anesthesia , 2 nd Ed. Lippincott,1992.

Respiratory Effects of Sedatives:

Respiratory Effects of Sedatives From: Barash, Cullen, Stoelting. Clinical Anesthesia , 2 nd Ed. Lippincott,1992.

Cerebral Effects of Sedatives:

Cerebral Effects of Sedatives From: Barash, Cullen, Stoelting. Clinical Anesthesia , 2 nd Ed. Lippincott,1992.

Delirium:

Delirium Definition: rambling and incoherent speech, together with altered sensory perception and disorientation Hallmark is its acute onset & fluctuating clinical course Most common mental disorder in hospitalized elderly patients Treatment Treat the underlying medical /surgical condition Haloperidol Only drawback is its delayed onset of action

Delirium:

Delirium From: Rogers, Tinker, Covino, Longnecker. Principles and Practice of Anesthesia. Mosby, 1993.

Delirium: Treatment with Haloperidol:

Delirium: Treatment with Haloperidol From: Marino. The ICU Book, 2 nd Ed. Lippincott Williams & Wilkins, 1998.

Delirium Tremens:

Delirium Tremens Accompanies alcohol withdrawal Preferred sedatives are benzodiazepines Haloperidol can aggravate the delirium and lower the seizure threshold Clonidine can also be helpful if hypertension accompanies the withdrawal Synergistic with benzodiazepines in regards to sedation Can be fatal if not recognized and treated

Impact of Altered Hepatic and Renal Function:

Impact of Altered Hepatic and Renal Function

Sedatives:

Sedatives Thiopental : hepatic and renal disease decrease the plasma protein binding of thiopental, increasing the free fraction of the drug and resulting in enhanced sensitivity to thiopental Diazepam : severe hepatic disease and chronic renal disease reduce protein binding and increase the free fraction Lorazepam : renal disease has little influence, but severe hepatic disease decreases its clearance rate Midazolam : clearance affected by hepatic disease

Sedatives:

Sedatives Etomidate : hepatic and renal disease cause a decrease in protein binding; hepatic disease prolongs the elimination half-life Propofol : no changes in pharmacokinetics reported in the presence of hepatic or renal disease Ketamine : hepatic disease affects clearance rate Dexmedetomidine : decreased clearance in hepatic disease, but no pharmacokinetic changes with renal disease

Analgesics:

Analgesics Morphine : hepatic disease increases the free fraction and prolongs elimination Meperidine : hepatic disease increases the free fraction and prolongs elimination; seizures can result from accumulation of normeperidine in patients with renal disease Fentanyl : hepatic disease decreases elimination

Assessment of Paralyzed Patients:

Assessment of Paralyzed Patients Neuromuscular blocking agents are commonly used in the ICU Indications: Mechanically ventilation Refractory intracranial hypertension Shivering (increases O 2 consumption) Tetanus Malignant hyperthermia Status epilepticus Status asthmaticus

Assessment of Paralyzed Patients:

Assessment of Paralyzed Patients Neuromuscular blocking agents do not have analgesic, sedative, or amnestic properties Need to administer the lowest effective dose guided by monitoring with a peripheral nerve stimulator

Questions:

Questions