Anaesthesia for elderly
- 2. PROPOFOL INDUCTIONS 25 – 81 YRS Schnider. Anesthesiology 1999; 90:1502 DOSE 2 mg/kg < 65 yrs, 1 mg/kg > 64 yrs Injection time 13 – 24 s LOSS OF CONSCIOUSNESS Young = old = 40 s RETURN OF CONSCIOUSNESS 30 yrs – 6 min, 75 yrs – 10 min SYSTOLIC BP < 100 mm Hg 50% < 80 mm Hg 8% Habib. Br J Anaesth 2002; 88:430
- 3. PROPOFOL INDUCTIONS > 65 YRS BOLUS DOSE (< 30 s) No concurrent drugs 1.5 mg/kg • Concurrent drugs 1.0 mg/kg HYPOTENSION • Continues for 10 min after injection SLOWER INJECTION (1–2 min) • Less hypotension, LOC with < 1.0 mg/kg • LMA
- 4. ANESTHETIC INDUCTION > 65 yrs MASK DECREASED AIRWAY REFLEXES IN ELDERLY • BP STABILITY: MASK > IV INDUCTIONS – Kirkbride et al. Br J Anaesth 2001;87:166P • SEVOFLURANE “NOT JUST FOR KIDS”
- 5. Muscle Relaxant→ shorter versus longer Aging affects the neuromuscular junction in many ways: 1. The distance of the junction ↑ 2. The number of ACh vesicle ↓ 3. Receptors of ACh ↓ 4. Sensitivity of ACh receptors — ↑Postoperative pulmonary complications after long- acting Ms relaxant (advanced age, ↑duration, hypothermia , ↑density of neuromuscular block)
- 6. Opioids Increases in potency for alfentanil, fentanyl, and remifentanil were demonstrated in EEG studies. A reduction in dosage in the elderly would be recommended. Fentanyl • Dose should be reduced to ½ to achieve the same effect. Alfentanil • Same recommendation as fentanyl. • Remifentanil • bolus→ ½
- 7. Volatile agents ↓cardiac output → more rapid onset of the action. Recovery from a volatile agent may be prolonged because of an ↑volume of distribution (↑body fat). The MAC of inhalational is ↓by 6% per decade of age over 40 years. (Propofol, Desf, Sevo) with BIS →Rapid emergence. The ↓lipid-solubility of sevoflurane and desflurane has advantage in the elderly: More rapid control of anesthetic depth than higher lipid-solubility agents. A faster emergence from anesthesia. (desflurane
- 9. Sedation in elderly Comparison of Propofol/ Ketamine versus Midazolam/ Ketamine for Sedation during Peribulbar Nerve Block. Ashraf A. AbdelHalim ketamine in low dose may be a useful alternative to opioid adjuncts during propofol and midazolam sedation. Both propofol-ketamine and midazolam- ketamine combinations provided satisfactory and safe sedation and analgesia during peribulbar nerve block, but the propofol-ketamine group had a rapid recovery and early discharge from the postanesthetic care unit (PACU).
- 10. PERIOPERATIVEPERIOPERATIVE BETA-BLOCKADE – POSSIBLEBETA-BLOCKADE – POSSIBLE ANESTHESTIC BENEFITSANESTHESTIC BENEFITS Secondary Observations Zaugg. Anesthesiology 1999; 91:1674 DECREASED ANESTHETIC REQUIREMENTS FASTER EMERGENCE DECREASED ANALGESIC REQUIREMENTS
- 11. PERIOPERATIVEPERIOPERATIVE BETA-BLOCKADEBETA-BLOCKADE THERAPEUTIC TARGETTHERAPEUTIC TARGET HEART RATE 55 – 65 bpm SYSTOLIC BP >100 mm Hg BEFORE, DURING, & AFTER SURGERY INDICATIONSINDICATIONS HIGH RISK = 3 MAJOR CRITERIA INTERMEDIATE RISK = ANY 2 MINOR OR 1-2 MAJOR CRITERIA Auerbach. JAMA 2002; 287:1435
- 12. PERIOPERATIVE MYOCARDIALPERIOPERATIVE MYOCARDIAL INFARCTIONSINFARCTIONS MOST OCCUR ON DAY OF SURGERY CARDIAC TROPONIN I LOWER IN BETA-BLOCKED PATIENTS Zaugg. Anesthesiology 1999; 91:1674
- 13. Diabetic NeuropathyDiabetic Neuropathy •Kitamura. Anesthesiology 2000; 92: 1131 High spinalHigh spinal •Core T (oC) = 34.37 + 0.15 (T dermatome) •Frank. Anesthesiology 2000; 92: 1330 Advanced ageAdvanced age •Core T (oC) = 36.72 – 0.03 (age in yrs) •Frank. Anesthesiology 2000; 92: 1330 INTRAOPERATIVE HYPOTHERMIAINTRAOPERATIVE HYPOTHERMIA Who Is at Risk?Who Is at Risk?
- 14. MINIMUM DIASTOLICMINIMUM DIASTOLIC PRESSURE :PRESSURE : WHEN TREATING SYSTOLIC HYPERTENSION, KEEP DIASTOLIC PRESURE •WITHIN 10% BASELINE •GREATER THAN 60 mm Mg TRANSFUSION TRIGGERTRANSFUSION TRIGGER HCT 30HCT 30 Wu. N Engl J Med 2002;345:12 30
- 15. ALVEOLAR CONCENTRATIONS UNDERESTIMATE BRAIN CONCENTRATIONS DURING EMERGENCE FROM IS0FLURANE Lockhart. Anesthesiology 1991; 74: 575 Conc. Ratio: Cerebral Alveolar 0-6 min 0.69 0.24 6-12 0.34 0.10 12-18 0.24 0.07 24-30 0.10 0.05 90-120 0.05 0.02
- 16. ELDERLY TAKE LONGER TO EMERGE THAN YOUNGER PATIENTS LOWER MAC awake HIGHER PAIN THRESHOLD HYPOTHERMIA MORE LIKELY EMERGENCE HYPERTENSION RELUCTANCE TO TURN OFF VAPORIZER LONGER DURATIONS OF ACTION RELATIVE DRUG OVERDOSES
- 17. DOES EPIDURAL ANESTHESIA REDUCE MAC? Yes, by 50%! Hodgson. Anesthesiology 1999; 91: 1687 DOES EPIDURAL ANESTHESIA shift BIS50 to higher index? Yes Hodgson. Anesthesiology 2001; 94: 799 DOES SPINAL OR EPIDURAL ANESTHESIA AFFECT SEDATIVE REQUIREMENTS? YES! Pollock. Anesthesiology 2000; 93: 728
- 18. Regional versus general Regional … complete block of stress response Pre-emptive analgesia No studies in elderly to show that regional is better than general in ambulatory surgery. Neuraxial, plexus or nerve block →↑risk of persistant numbness, nerve palsies,.. Clonidine is valuable adjuvant to local→ choice of dose to avoid sedation &hypotension.
- 19. Postanesthesia Recovery Cardiac and pulmonary complications are most common ↑ incidence of regurgitation and aspiration Longer duration of drugs More likely to develop CHF Unable to tolerate heat loss More likely to be confused and combative Increased risk of morbidity and mortality
- 20. Postoperative Hypothermia… Maintaining normothermia →↓cardiac morbidity by 55% . Pain … Effective analgesia→↓ incidence of myocardial ischemia , pulmonary complication, accelerate recovery , early mobilization, ↓ hospital stay & ↓medical care cost. Inadequate pain control due to concerns about over dosage, adverse response ,drug interactions,…. Pain perception & expression are affected changes in mental status. Pre-emptive, multimodal approaches. Balanced analgesia opioids, nonopioids,& local anesthetic
- 21. Postoperative bMobilization Multiple studies support that early mobilization yield benefits •Decreased length of hospital stay •Faster attainment of functional recovery BECAUSE : Prolonged bedrest is associated with increased risk of DVT, pulmonary embolism, and deconditioning in elderly Remove tethers (catheters, tubes, drains, etc.) as soon as feasible Utilize physiotherapy and devices to aide mobility as needed Diabetes Control blood sugar should be kept below 200 on day of surgery and the first two post-operative days.
- 22. Postoperative cognitive impairment MORE than 50 yr ago clinicians reported changes in mental function after anesthesia and surgery in the elderly
- 23. Postoperative delirium Acute disorder of cognitive function over a brief period of time often lasting for few days to few weeks and typically having fluctuating course. Associated with Longer hospital stay Greater hospital costs Acute onset (hours to days) with fluctuating course throughout the day
- 24. Postoperative delirium Clinical features Change of consciousness and recognition Cognitive abnormalities Disorientation Language difficulty Impairment of learning and memory Emotional disturbances Anxiety Fear Anger Irritability Depression
- 25. Clinical Presentation and Diagnosis Time of onset emergence delirium (ED), postoperative delirium (PD) ED during or immediately after emergence from GA, resolves within minutes or hours, all age groups, predominance in children, directly correlated with GA (during the emergence process, mimics stage II (excitation) of ether anesthesia, resolves without sequelae) substance- induced delirium. PD postoperative days 1 and 3, resolves within hours to days (symptoms may persist for weeks to months), result in complete recovery than other forms of delirium interval delirium (after a lucid interval) ICU delirium ICU, MV, no distinction between medical and surgical patients ICU psychosis
- 26. Postoperative delirium )Pathogenesis( CNS changes with age Loss of nerve cells Decreased in cerebral blood flow Changes in neurotransmitter system Decreased acetylcholinesterase activity Carbonic anhydrase activity Muscarinic receptor Serotonin receptors Abnormal levels of endorphins, serotonin, neuropeptides in CSF EEG : slowing of dominant posterior alpha rhythm and abnormal slow wave activity
- 27. Postoperative delirium )Risk factors( Older age Cognitive impairment ↓postoperative Hb Markedly abnormal sodium, potassium and glucose Alcohol abuse Non cardiac thoracic operation History of delirium use of a urinary catheter use of physical restraints preoperative depression Preoperative narcotic, anticholinergics ,benzodiazepine Lorazepam ICU delirium ↓postoperative oxygen saturation History of C.V.Ds Untreated pain perioperative hypotension and hypoxemia BUN : creatinine ratio >18 Infections
- 28. Preventive Measures 1. Orientation • Assess baseline mental status • Orientation cues (clock, calendar) • Perception aids (glasses, hearing aids) • Sleep-wake (Trazodone 25 QHS PRN) • Involve family and caregivers 1. Minimize iatrogenesis • Stop inappropriate medications • Minimize urinary catheter use • Minimize restraints (actual & perceived)
- 29. Preventive Measures 3. Medical Housekeeping • CNS oxygen delivery (Sat > 95%) • Minimization of anticholinergic , meperidine ,benzodiazipenes & antihistaminic • Keep systolic Bp >90 mmHg, Hct >30 • Hydration (BUN/creat ratio) • Attention to electrolytes/glucose • Extra vigilance for medical complications 3. Rehab • Bowel regimen • Nutrition (extra supplements, TF) • Early mobilization • Pain control (RTC Tylenol)
- 30. Postoperative delirium Medication for symptom control Antipsychotics Haloperidol or newer antipsychotic agent ?? Goal is to control disruptive symptoms and avoid obtundation Taper in 3-5 days Benzodiazepine Paradoxical agitation Treat withdrawal from alcohol of sedative drugs Recently, the use of melatonin to treat delirium Has produced some benefit
- 31. Postoperative cognitive dysfunction Risk Factors Increased age. Major surgery Increased duration of anesthesia Low level of education Need for second operation. Postoperative infections Respiratory complications, Postoperative pain
- 32. Postoperative cognitive dysfunction Deterioration of intellectual function presenting as impaired memory or concentration. Abrupt decline in cognitive function heralds: • Loss of independence • Withdrawal from society • Death Not detected until days or weeks after anesthesia Duration of several weeks to permanent Diagnosis is only warranted if: • corroborated with neuropsychological testing • evidence of greater memory loss than one would expect due to normal aging
- 33. Postoperative cognitive dysfunction Few prospective studies on long term cognitive outcome after outpatient surgery But they have better outcome at discharge. Incidence was significantly ↑ with major &orthopedic surgery compared with Minimally invasive surgery. Early versus late
- 34. Postoperative cognitive dysfunction Etiology Unclear GA toxic effects on CNS structure and function? Cerebrovascular disease, cerebral hypoperfusion, genetic susceptibility, alteration in neurotransmitter function, neurohumoral stress, CNS inflammatory phenomenon Hypotension, hypoxemia, ischemia potential etiology Nonspecific enolase ? may be useful as a marker of early POCD (small studies of cardiac surgery patients) Regional versus General Anesthesia : Williams-Russo (prospective, randomized study): no statistically significant differences (epidural V.S. general) Wu (review 24 studies): the choice of anesthesia does not influence the incidence of POCD
- 36. Conclusion Preoperative assessment of organ function &reserve. Intraoperative management of co-existing disorder. Normothermia Vigilant postoperative monitoring &pain control Risk of postoperative delirium can be reduced with careful attention to risk factors