Review of Systems

1. Review of Systems Anatomy, Physiology, and Complications

2. Preop respiratory assessment • SpO2 on room air establishes a baseline. • Respiratory history should include: • Smoking history – pack years • Chronic conditions • Home O2 use, CPAP

3. Respiratory System • Effects of anesthesia: • Halogenated anesthetics, muscle relaxants, propofol cause apnea. • This is an expected effect of these drugs. • Other agents (narcotics, benzos) cause respiratory depression.

4. Respiratory System • The respiratory system is the first to be assessed on admission to PACU. • Initiate oxygen delivery; should come from OR with pulse ox and O2. • “The patient shall be continually evaluated and treated during transport with monitoring and support appropriate to the patient’s condition.” • Basic Standards for Postanesthesia Care • http://www.asahq.org/For-Healthcare-Professionals/Standards-Guidelines-and-Statements.aspx

5. Assessment • Listen to breath sounds on admission for general anesthesia patients. • Is an ASPAN standard.

6. Items for Further Review • Chapter 31 in Core Curriculum for discussion of oxygen delivery devices. • Mechanical ventilation. • Acid-base interpretation.

7. Respiratory Complications • Residual obtundation after 15-30 min. is probably due to opioids, benzos. • Partial airway obstruction or hypoventilation  hypoxemia due to inadequate tidal volumes, atelectesis.

8. Respiratory Complications • Treat with: • Oxygen and observation. • Stir-up regimen. • If necessary, reverse opioids and benzos – with care. • Reintubation and ventilation until adequate muscle strength.

9. Aspiration • Primarily an intraoperative problem, but can happen in PACU. • Is the most common, serious complication of anesthesia.

10. Residual neuromuscular blockade • Risk factors: • Long-acting neuromuscular blocking agents. • Inadequate reversal agents. • PC deficiency. • July and August. • Signs and symptoms: • Air hunger. • Discoordinated movements. • Hypertension, tachycardia. • Dysphagia.

11. Treatment • More reversal in possible. • Support airway, • Reintubate pt until block has worn off. • Sedate pt.

12. Aspiration • Risk factors: • Nonfasted. • GERD. • Obstetric. • Obese. • Elderly immobilized pts. • Emergency surgery increases the risk of aspiration 4 times over elective surgery.

13. Aspiration • Pathophysiology of damage: • Acidic fluid is aspirated. • Results in: • interstitial edema • intra-alveolar hemorrhage • atelectesis • increased airway resistance • hypoxemia

14. Immediate Management • Lower head quickly. • Turn head to side. • Suction oropharynx.

15. Aspiration • Will see symptoms within 2 hrs. • Will see dyspnea, tachypnea, cough, fever, wheezing, rales, and hypoxemia. • CXR: will eventually see infiltrates, but not initially.

16. Treatment of Aspiration • Airway patency, adequate ventilation, and supplemental oxygen. • Pulmonary toilet and airway suctioning. • Bronchoscopy may be indicated. • Nebulized bronchodilators. • Prophylactic antibiotics and corticosteroids are not indicated.

17. Stridor or Croup • Noisy inspiration. • Usually seen in infants or children because of smaller airways. • Treatment: • Oxygen with humidification. • HOB at 45-90. • Nebulized racemic epinephrine 2.25%, 0.5 ml with 3 ml NSS. May repeat q 30 min up to 3 times. • Dexamethasone 0.5mg/kg IV q 6 hrs for moderate symptoms.

18. Laryngospasm • Caused by a closure reflex of the vocal cords. • Signs and symptoms: • High-pitched inspiratory stridor • Tracheal tug • Apprehension

19. Laryngospasm • Treatment: • Oxygen with humidification. • HOB at 45-90. • Lidocaine 1-1.5 mg/kg. • Stay calm, and calm the pt. • Have pt take short, shallow breaths. • Bag-valve-mask device can break a spasm. Sux. • Can cause negative pressure pulmonary edema.

20. Obstructive Sleep Apnea (OSA) • Characterized by periodic, partial or complete obstruction of the upper airway during sleep. • Cessation of airflow for more than 10 sec., despite continuing ventilatory effort, 5 or more times per hr of sleep. • Usually associated with a decrease in SpO2 of more than 4%.

21. Obstructive Sleep Apnea • Risk factors: • Obesity, especially with a neck circumference of 15.5 – 16.5 inches. • 60-90% of OSA pts are obese. • 2% to 26% of the US population have OSA. • 80% to 90% are unaware that they have it. • Many are diagnosed during their pre-anesthesia assessment.

22. Obstructive Sleep Apnea • In non-obese and pediatric pts, risk factors are craniofacial abnormalities, nasal obstruction, and large tonsils.

23. Signs and Symptoms of OSA • Snoring, apnea during sleep, periodic snorting and arousal during sleep. • Daytime sleepiness and fatigue. • Hypertension. • Personality and behavioral changes. • Decreased cognition and intellectual function.

24. Diagnosis of OSA • Sleep lab study which requires an overnight analysis. • Apnea risk evaluation system (ARES) unicorder. • Similar to a holter monitor. • Records oxygen saturation, pulse rate, airflow, head position and snoring decibel level.

25. Screening Tools • STOP-Bang • Requires neck circumference. • Must actually see patient. • Berlin Questionnaire • Can be done over the phone. • ASA Checklist • Requires physical exam of pt. • American Sleep Apnea Association Snore Score • Can be done over the phone.

26. Effects of Anesthesia and Surgery on OSA Patients • Risk of airway obstruction following extubation. • Spontaneous ventilation against an obstructed airway can cause negative pressure pulmonary edema. • When extubated, should be fully awake, & should have full recovery from neuromuscular blockade.

27. Postoperative Management • Analgesia • Be judicious with narcotics. • Regional analgesia and epidurals. • Oxygenation. • Supplemental O2 until pt can maintain baseline SpO2. • Continuous pulse oximetry if in-pt. • CPAP after surgery if pt uses it at home.

28. Postoperative Management • Positioning. • Reverse trendelenberg in hospital. • At home, sleep in lateral or prone position. • Sitting position in recliner. • Not supine.

29. In-Patient vs Out-Patient • Outpatient OK when local or regional anesthesia used. • T&A in kids under 3 yo with OSA – in-pt. • In general, pts with OSA should be monitored for 3 hrs longer than usual prior to discharge.

30. Obstructive Sleep Apnea • Practice Guidelines for the Perioperative Management of Patients with Obstructive Sleep Apnea. • http://www.asahq.org/For-Members/Practice-Management/Practice-Parameters.aspx • Published in Anesthesiology, May 2006. • Creating a Safer Perioperative Environment with an Obstructive Sleep Apnea Screening Tool • L Lakdawala. JoPAN, Feb 2011, 15-24.

31. Asthma • One of the most common chronic diseases in the US. • Incidence and severity is increasing. • An inflammatory disease of the airways. • Asthma causes: • Airway wall thickening. • smooth muscle contraction. • Airway obstruction. • Airway remodeling.

32. Treatment of Asthma • Inhaled corticosteroids reduce the immediate and late phase responses to allergens, and actually prevent the airway remodeling. • Sympathomimetic agents – cause bronchodilatation, stimulate mucociliary transport, affect the function of inflammatory cells.

33. Effect of Anesthesia on Asthma • All inhalational anesthetics produce bronchodilatation; some are airway irritants. • Some neuromuscular blocking agents cause histamine release.

34. Preop Management of Asthma • Have pt bring his/her inhaler to hospital. • Continue inhaled or systemic corticosteroids up to the time of surgery. • A nebulized beta antagonist should be given prior to surgery.

35. Postop Management of Asthma • Postop, assess the pt for s/s of asthma: wheezing, diminished breath sounds, prolonged expiration. • Anticipate giving a neb of albuterol.

36. Phase II Respiratory Care • SpO2 on admission and on discharge from Phase II. Is NOT an ASPAN standard. • For asthmatics, instruct them on when to use their inhaler. • For kids after T&A, tell parents to check their breathing when asleep, and to wake them up periodically.

37. Cardiovascular System • Anesthesia has a profound effect on the CV system. • Varies according to agent used.

38. Cardiovascular System • Most halogenated anesthetics cause myocardial depression: • Decreased HR • Decreased contractility • Decreased CO Also cause: • Systemic vasodilatation

39. Hypertension • Preop, obtain BP. • Hypertension can be due to anxiety; will resolve after surgery. • Pts on antihypertensives should be told to take their med(s) the morning of surgery, except diuretics.

40. Postop Hypertension • Significant hypertension should be reported to the anesthesiologist. • Treat hypertension with analgesics as well as antihypertensives. • May also be due to a full bladder.

41. Prevalence of CV Disease • Many pts have underlying CV disease. • Always be alert to intraop MIs, exacerbation of pre-existing conditions, angina.

42. Effects of Anesthesia on the CNS • IAs produce an alteration of neuronal excitability. • IAs cause cerebral vasodilatation and increase ICP. • Are potent metabolic suppressants. • Propofol produces cerebral vasoconstriction.

43. Neurologic Care • Cerebral perfusion pressure: • Is a measure of the cerebral auto regulation, which maintains a relatively constant cerebral blood flow and ICP to provide adequate oxygen and nutrients to the brain. • Need a minimum of 60 mm Hg systolic to provide minimally adequate blood flow to the brain.

44. Cerebral Perfusion Pressure • CPP=MAP-ICP • MAP=SBP + DBP x 2 3 ICP - 4-15 mmHg

45. Perioperative Visual Loss • Permanent impairment or total loss of sight. • Associated with spinal surgery, the prone position, and general anesthesia. • Occur in less then 0.2% of spine surgeries.

46. Perioperative Visual Loss • Risk factors: • Intraoperative hypotension. • Substantial blood loss. • Direct pressure to eyes from a sheet roll or headrest. • Assess pt’s vision when pt becomes alert. • Practice Advisory for Perioperative Visual Loss Associated with Spine Surgery • http://www.asahq.org/For-Members/Practice-Management/Practice-Parameters.aspx

47. Effects of Anesthesia on Thermoregulation • The hypothalamus regulates body temperature. • Controls body temperature through effector mechanisms. • Vasomotor. • Metabolic. • Sudomotor. • Behavioral changes.

48. Effects of Anesthesia on Thermoregulation • The hypothalamus is depressed. • The IAs cause vasodilatation. • The muscle relaxants, and to a lesser extent, the IAs, cause muscle paralysis, which prevents shivering.

49. Effects of Anesthesia on Thermoregulation • No behavioral alterations are possible. • With a spinal, the body is a poikilotherm below the level of the spinal. • At or below a temp of 95 F, the body’s ability to rewarm itself is impaired.

50. Effects of Hypothermia • Initially, causes vasoconstriction and hypertension. • Later, causes bradycardia and diminished CO. • Increased blood viscosity. • Coagulation cascade and platelet function are impaired, esp. below 95.