Anesthesia at Remote Locations Dr Abdollahi 10282020 1

Anesthesia at Remote Locations Dr Abdollahi 10/28/2020 1

Remote anesthesia Anesthesiologists are increasingly being asked to provide anesthetic care in locations outside of the OR. It is the responsibility of the anesthesiologist to ensure that the location meets the ASA guidelines for safety. 10/28/2020 2

Locations 1. 2. 3. 4. 5. 6. 7. 8. Radiology suites (MRI, CTSCAN) Cardiac catheterization laboratories Psychiatric units Radiation therapy Gastroentrology Pulmonary medicine Urology (ESWL) General dentistry 10/28/2020 3

Anesthesiologists must maintain the same high standard of anesthetic care provided in the operating suite. 10/28/2020 4

Large, mobile pieces of radiologic equipment, radiation hazards, intense magnetic fields, paramedical personnel not familiar with the anesthesia team, and other factors may make the delivery of quality anesthetic care problematic. 10/28/2020 5

Remember that the key to efficient and safe remote anesthetic relies on open communication between the anesthesiologist and non-operating room personnel 10/28/2020 6

1994 Guidelines for non-operating room anesthetizing locations Reliable oxygen source with backup. Suction source. Waste gas scavenging. Adequate monitoring equipment. Self-inflating resuscitator bag. Sufficient safe electrical outlets. Adequate light and battery-powered backup. Sufficient space. Emergency cart with defibrillator, emergency drugs, and emergency equipment. Means of reliable two-way communication. Compliance with safety and building codes. 10/28/2020 7

Remote monitoring Qualified anesthesia personnel must be present for the entire case. Continuous monitoring of patient’s oxygenation, ventilation, circulation, and temperature. Oxygen concentrations of inspired gas: low concentration alarm. Blood oxygenation: pulse oximetry. Ventilation: end-tidal carbon dioxide detection and disconnect alarm. Circulation: EKG, ABP (q 5 min), invasive BP, and oximetry. 10/28/2020 8

Anesthesia techniques used in non-operating room anesthetizing locations range from no anesthesia, to sedation/ analgesia, to general anesthesia. 10/28/2020 9

RADIOLOGY SUITE Radiologic procedures that may require sedation/analgesia include a number of imaging modalities such as radiology, ultrasonography, CT, and MRI, as well as various interventions that may be directed by the imaging modalities. 10/28/2020 10

Advances in imaging capability, as well as the availability of advanced endovascular devices and RF probes, has increased the use of radiology suites and increased the demand for anesthesia services in these areas 10/28/2020 11

Intervention Percutaneous drain placement, Nephrostomy tube placement, Percutaneous placement of feeding tubes, Placement of intravascular access catheters, Thrombolysis, Dilation of stenotic vessels, Embolization of tumors or arteriovenous malformations (AVMs), Tissue biopsy specimens may be obtained under radiologic guidance 10/28/2020 12

Conditions may be treatable in the radiology suite • • • Some solid tumors may be treated by guided tissue ablation. Painful metastases may be treated by guided radiofrequency (RF) ablation. Cerebrovascular lesions may be treated endovascularly with guidance by digital subtraction angiography. 10/28/2020 13

General consideration Medical history Immobile Claustrophobia Environment (Crowded, Bulky radiology equipment , high voltage, change of position ) Lack of gas scavenging 10/28/2020 14

Radiation Safety Radiation exposure is potentially harmful both in terms of its somatic effects during an exposed individual's lifetime (e. g. , production of leukemia) and in terms of genetic injury resulting in fetal abnormalities caused by damage to the gonadal cells or developing fetus. 10/28/2020 15

The maximal permissible radiation dose for occupationally exposed persons is 5 O millisieverts (m. Sv) annually, a lifetime cumulative dose of 10 m. Sv x age, and monthly exposure of 0. 5 m. Sv for pregnant women. 10/28/2020 16

Radiation exposure can be limited by wearing appropriate lead aprons and thyroid shields, using movable leaded glass screens, and using innovative techniques such as video monitoring and remote mirroring of monitor data to allow remote conduct of anesthesia when appropriate and required for the safety of anesthesia personnel. Clearly, open communication between the radiology and anesthesia teams is essential to minimize radiation exposure. Adequate warning of initiation of imaging by the radiology team allows the anesthesia personnel to take appropriate precautions in a timely fashion 10/28/2020 17

Iodinated Contrast Media Iodinated contrast agents are often used in diagnostic and therapeutic radiologic procedures to assist imaging. Adverse reactions to contrast media range from mild to immediately lifethreatening, and etiologies include direct toxicity, idiosyncratic reactions, and allergic reactions, either anaphylactic or anaphylactoid Crable 10/28/2020 18

Predisposing factors include a history of bronchospasm, history of allergy, underlying cardiac disease, hypovolemia, hematologic disease, renal dysfunction, extremes of age, anxiety, and medications such as B-blockers, aspirin, and nonsteroidal anti-inflammatory drugs. Prompt recognition plus treatment of contrast media reactions is important to prevent progression of less severe reactions and lessen the impact of severe reactions 10/28/2020 19

Treatment is symptomatic, for example, oxygen and bronchodilators to treat bronchospasm. Severe or resistant bronchospasm may require treatment with epinephrine. Typically, corticosteroids and antihistamines are given to symptomatic patients under the assumption that the etiology is immunologic. 10/28/2020 20

Prophylaxis pretreatment with prednisolone, 5 O mg 12 hours before a procedure requiring contrast media, and diphenhydramine, 5 O mg immediately before the procedure. 10/28/2020 21

Renal dysfunction is well documented in association with radiologic contrast media, particularly in patients with preexisting renal dysfunction and most especially in patients with preexisting renal dysfunction related to diabetes. 10/28/2020 22

Most cases of new or worsened renal function related to contrast media are self-limited and resolve within 2 weeks. However, some patients may progress to the point of requiring dialysis. 10/28/2020 23

Recent studies have demonstrated a reduction in contrast media nephrotoxicity by the administration of acetylcysteine. Lifethreatening lactic acidosis may develop in non-insulindependent diabetic patients who are receiving metformin and have preexisting renal dysfunction if their renal function declines further. Extra care is needed when patients taking metformin receive radiologic contrast media. 10/28/2020 24

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Anesthesia in the Radiology Suite Minimal to moderate sedation/analgesia is the technique used for most patients undergoing these procedures. 10/28/2020 26

For most adults, combinations of intravenous benzodiazepines and opioids (i. e. , titration of midazolam and fentanyl) are sufficient to ensure comfort during the procedure. The use of more potent anesthetic agents such as propofol, methohexital, and ketamine is best reserved for specialists in anesthesia. However, understanding the procedure in question is important in selection of the appropriate anesthetic technique. The patient's condition, the anticipated level of stimulation, and patient position during the procedure all important considerations. 10/28/2020 27

A patient undergoing ultrasound-guided hepatic biopsy might have ascites, which would render that patient prone to aspiration if sedated, and penetration of the hepatic capsule by the biopsy needle would be anticipated to be quite painful. Such a patient might benefit from general anesthesia rather than sedation/analgesia. 10/28/2020 28

Procedures that might be anticipated to last several hours may best be performed with general anesthesia at the outset rather than late conversion after failure of sedation/ analgesia, when patient access might be limited by catheter placement and radiologic equipment. 10/28/2020 29

Pediatric patients merit special consideration. Some radiologic procedures require patients to remain still for prolonged periods, which may not be possible for infants and children, even with sedation/analgesia. (chloral hydrate orally for radiologic procedures 25 to 5 O mg/kg for infants younger than 4 months, 5 O mg/kg for older children) 10/28/2020 30

Patients with difficult airways, whether anticipated or not, can be problematic in settings outside the operating suite. I prefer to perform anticipated difficult endotracheal intubations in the operating suite with its improved availability of skilled assistants and specialized equipment. Once the airway is controlled, the patient can be transported to the site of the planned procedure should it be necessary to perform the procedure outside the operating suite. 10/28/2020 31

MAGNETIC RESONANCE IMAGING The most significant risk posed in the MRI suite is the effect of the magnet on ferrous objects. 10/28/2020 32

MRI scanning has a number of limitations. Imaging is time consuming, and individual scans may take up to 20 minutes, with an entire examination lasting more than 1 hour. Switching on and off of the RF generators produces loud noises (>90 d. B). 10/28/2020 33

MRI Hearing protection is mandatory for both the patient and health care personnel who must be present in the scanning room. Heating resulting from the RF energy of nonferromagnetic prosthetic devices has not proved to be a problem. Body surfaces do absorb this RF energy, but it is unlikely that the patient's temperature will increase by more than 1°C. 10/28/2020 34

MRI The most significant risk posed in the MRI suite is the effect of the magnet on ferrous objects. Dislodgement and malfunction of implanted biologic devices or other objects containing ferromagnetic material are also real possibilities. Such items include shrapnel, vascular clips and shunts, wire spiral endotracheal tubes, pacemakers, automatic implantable cardioverter-defibrillators (ICDs), mechanical heart valves, and implanted biologic pumps. 10/28/2020 35

MRI Tattoo ink may contain high concentrations of iron oxide. Burns at tattoo sites have been reported after exposure to MRI magnetic fields, but such incidents are very rare and the presence of, for example, permanent eyeliner should not exclude the patient from MRI examination. 10/28/2020 36

Anesthetic Management for MRI Anesthesia in the MRI suite poses several unique problems, including the following: 1. Limited patient access and visibility, especially when the patient must be placed head first into the magnet 2. Absolute need to exclude ferromagnetic components 3. Interference/malfunction of monitoring equipment produced by the changing magnetic field and RF Currents 4. Potential degradation of the imaging caused by the stray RF currents produced by the monitoring equipment and leads 5. The necessity to not move the anesthetic and monitoring equipment once the examination has started to prevent degradation of magnetic field homogeneity 6. Limited access to the MRI suite for emergency personnel in accordance with the recommended policies noted earlier 10/28/2020 37

A common approach now is to induce anesthesia in an induction area adjacent to the MRI suite outside the magnetic field by using conventional equipment with the patient on a dedicated MRI transport table that is not ferromagnetic. 10/28/2020 38

MRI Because the patient's airway is not easily accessed during the MRI scan and because patient assessment and communication are limited by both the magnet bore in which the patient is placed and the loud noise associated with MRI scanning, deep sedation/analgesia is not advisable. Patients requiring more than moderate sedation/analgesia are probably most safely administered a general anesthetic with airway control by either endotracheal intubation or a laryngeal mask airway (LMA). 10/28/2020 39

Contraindications for MRI include: Shrapnel, vascular clips and shunts, wire spiral ETT’s, pacemakers, ICDs, mechanical heart valves, recently placed sternal wire, implanted biological pumps, tattoo ink with high concentrations of iron-oxide (permanent eyeliner), and intraocular ferromagnetic foreign bodies. 10/28/2020 40

Ferromagnetic items should never be allowed in the vicinity of the MRI magnet, including: scissors, pens, keys, gas cylinders, anesthesia machine, syringe pump, beeper, phone, and steel chairs. Cards with magnetic strips will be de-magnetized, including credit cards and ID badges. 10/28/2020 41

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ANESTHESIA FOR INTERVENTIONAl NEURORADIOl. OGY Include embolization of cerebral and dural AVMs, coiling of cerebral aneurysms, angioplasty of atherosclerotic lesions, and thrombolysis of acute thromboembolic stroke. 10/28/2020 55

These procedures may involve deliberate hypotension, deliberate hypercapnia, or deliberate cerebral ischemia as part of the procedure; a requirement for rapid transition between deep sedation/ analgesia and the awake, responsive state; and severe potential procedural complications. 10/28/2020 56

Anesthetic Management Preprocedural anesthetic evaluation is similar to that before neurosurgical procedures. Airway examination is important in as much as airway manipulation during the procedure is not possible because of interference with head positioning for imaging. Particularly important is a history of previous experience with radiologic procedures and any history of contrast media reaction Because blood pressure management is important for these procedures, preoperative evaluation for hypertension is important, as is good preoperative control of existing hypertension. 10/28/2020 57

Heparin is commonly administered during these procedures, with a target activated clotting time (ACT) of 2 to 2. 5 times the baseline value. Deliberate hypotension is frequently used during AVM embolization to decrease flow to feeding vessels, as well as during some trial balloon occlusions. Agents such as esmolol, labetalol, or sodium nitroprusside are all useful in this situation. Deliberate hypertension is called for during cerebral ischemia in an attempt to maximize collateral flow. 10/28/2020 58

Phenylephrine is generally used, both as a bolus and as an infusion titrated to increase systolic blood pressure 30%to 40% above baseline. Close monitoring of ECG parameters for signs of myocardial ischemia is critical in this case. Smooth emergence from anesthesia is important in these patients, who may be prone to device migration or intracranial hemorrhage. Administration of antiemetics before emergence is certainly reasonable, and precautions to avoid coughing andl/bucking" should be taken. 10/28/2020 59

INTERVENTIONAL CARDIOLOGY lnterventional cardiology procedures include coronary angiography and cardiac catheterization, coronary artery angioplasty/stenting, valvotomy, closure of intracardiac defects, electrophysiologic studies with pathway ablation, and cardioversion. Electrophysioiogic Studies and Catheter Ablation of abnormal Conduction Pathways , Pacemaker and Cardioverter- defibrillator implantation. 10/28/2020 60

The usual anesthesia management is by sedation/analgesia, with general anesthesia reserved for sedation failure, uncooperative patients, or those who require airway control to manage respiratory failure. Anesthetic agents used commonly include fentanyl and midazolam, sometimes supplemented with propofol. Sedation and analgesia are helpful in reducing the discomfort. 10/28/2020 61

Typical heparin doses range from 2500 to 5000 IV intravenously. For interventional procedures, higher heparin doses (i. e. , 10, 000 IV intravenously) are given, with a target ACT of over 300 seconds. Patients must be monitored carefully after protamine administration to detect the predictable peripheral vasodilation, as well as less predictable anaphylactic and anaphylactoid reactions or the rare catastrophic pulmonary vasoconstrictive crisis associated with protamine administration. 10/28/2020 62

Heparin are increasingly commonly being administered during interventional cardiac catheterization and have resulted in improved outcomes despite the reduction in heparin dose. Platelet aggregation inhibitors used have included abciximab, ticlopidine, and clopidogrel. Numerous studies have shown the benefits of anti platelet therapy in both acute and chronic coronary syndromes. A notable side effect of abciximab is elevation of the ACT independent of heparin. 10/28/2020 63

Coronary artery disease is assessed by detection of stenoses after injection of contrast medium selectively into each main coronary artery. Stenoses greater than 50%to 70%f the normal arterial diameter are considered hemodynamically significant, although lesser stenoses may be clinically important. Coronary artery disease is classified as one-, two-, or three-vessel disease or left main coronary disease. 10/28/2020 64

after dilation of the stenotic coronary artery, ventricular arrhythmias may develop and require treatment. 10/28/2020 65

Pediatric Cardiac Catheterization Medications administered for sedation include fentanyl, midazolam, propofol, and ketamine. Premedication with midazolam, 0. 5 mg/kg orally, can be particularly helpful. Some evidence has indicated that ketamine can increase oxygen consumption, so care must be taken to ensure that it does not impair diagnostic accuracy. 10/28/2020 66

complications Hypothermia Arrhythmia Tamponad Bleeding 10/28/2020 67

Elective Cardioversion Elective cardioversion is uncomfortable, and general anesthesia is required. Many medications have been used, including barbiturates, propofol, etomidate, and benzodiazepines. 10/28/2020 68

It should be noted that muscle relaxants are not typically needed for this procedure. Etomidate cause myoclonus and interfere by EKG and airway managment. 10/28/2020 69

ELECTROCONVULSIVE THERAPY Indications for ECT include major depression, mania, certain forms of schizophrenia, and perhaps Parkinson's syndrome. 10/28/2020 70

CONTRAINDICATION Pheochromocytoma is a contraindication to ECT. Relative contraindications include : • Increased intracranial pressure, • Recent cerebrovascular accident, • Cardiovascular conduction defects, • High-risk pregnancy, • Aortic and cerebral aneurysms. In these conditions, the risk of the patient's psychiatric illness and the side effects of antidepressant medications must be weighed against the risk associated with ECT and anesthesia. 10/28/2020 71

Mechanism ECT therapeutic effects are thought to result from release of neurotransmitters during the electrically induce grandmal seizure. 10/28/2020 72

Complications Seizure activity causes an initial parasympathetic discharge manifested by bradycardia, occasional asystole, premature atrial and ventricular contractions, or a combination of these abnormalities. Hypotension and salivation may be noted and then sympatric activity. ECG changes, including ST-segment depression and T-wave inversion, may also be seen after ECT without any of the myocardial enzyme changes consistent with myocardial infarction. 10/28/2020 73

Arrhythmias associated with ECT, even in patients with preexisting arrhythmias, are self-limited and not in themselves a contraindication to treatment. ECT has been found to be relatively safe even in high-risk cardiac patients, provided that careful management is provided. 10/28/2020 74

The most common causes of death are MI and arrhythmia 10/28/2020 75

Neuroendocrine responses to ECT include increased levels of stress hormones, including adrenocorticotropic hormone, cortisol, and arginine vasopressin, as well as prolactin and growth hormone. Norepinephrine and epinephrine increase immediately after ECT, and epinephrine levels decrease more rapidly thereafter. Glucose homeostasis is variably affected by ECT. Improvement in control of non-insulin-dependent diabetes is generally noted, whereas hyperglycemia may be seen when the diabetes is insulin dependent. 10/28/2020 76

ECT Pre-op the pt. These pt’s have often had this procedure multiple time, therefore you can use old records as templates. Place IV and give glyco (0. 2 mg IV). Treats the bradycardia/ asystole from the initial parasympathetic discharge from the seizure activity Hyperventilate the pt. with 100% O 2. Inflate the manual BP cuff in the arm opposite the IV and then give Sux. Place the bite block. Goal is a seizure 30 -60 seconds long. Ventilate until spontaneous respirations return. The parasympathetic discharge is often followed by a sympathetic discharge associated with HTN and tachycardia. This is treated with esmolol. 10/28/2020 77

Antidepressant Drug Therapy Antidepressants, monoamine oxidase inhibitors (MAOIs), serotonin reuptake inhibitors, lithium carbonate, or a combination of these drug. 10/28/2020 78

Tricyclic antidepressants block the reuptake of norepinephrine, serotonin, and dopamine into presynaptic nerve terminals, thereby increasing central sympathetic tone. Tricyclic antidepressants have anti. histaminic, anticholinergic, and sedative properties and also slow cardiac conduction. These side effects are less common with the newer types of antidepressant drugs such as trazodone, bupropion, and fluoxetine. The combination of centrally acting anticholinergics, such as atropine, with tricyclic antidepressants can increase postprocedural delirium. 10/28/2020 79

MAOIs can inhibit hepatic microsomal enzymes. They may interact with opioid analgesics and cause excessive depression. Used concomitantly with meperidine, MAOIs may result in severe, possibly fatal excitatory phenomena. 10/28/2020 80

Lithium carbonate prolongs the action of neuromuscular blocking agents. Elevated lithium levels, higher than therapeutic range, can prolong the action of benzodiazepines and barbiturates. Patients receiving lithium may demonstrate more cognitive side effects after ECT. The American Psychiatric Association recommends discontinuation of lithium therapy before ECT. 10/28/2020 81

Hypothyroidism is known to occur in patients who have been tacking lithium for long time (15 years or more). 10/28/2020 82

Anesthetic Management of Electroconvulsive Therapy Anesthesia and neuromuscular blockade are necessary during ECT to prevent psychological and physical trauma. Rapid recovery is desirable. 10/28/2020 83

particular attention paid to coexisting neurologic and cardiac disease, osteoporosis and other causes of bone fragility, and medications that the patient may be receiving. The patient may be a poor historian because of the psychiatric condition, and accompanying caregivers may need to provide the necessary history and assurance of fasting status. 10/28/2020 84

Glycopyrrolate (0. 2 mg intravenously), which does not cross the bloodbrain barrier, can reduce the occurrence of bradycardia and the amount of oral secretions associated with ECT. After preoxygenation, anesthesia is administered by peripheral intravenous catheter, and neuromuscular blockade is induced. When relaxation is adequate and satisfactory mask ventilation with oxygen is ensured, a bite block is placed and a stimulus is delivered to induce the seizure. 10/28/2020 85

If the patient has a hiatal hernia and gastroesophageal reflux, rapidsequence induction and endotracheal intubation with cricoid pressure may be a reasonable approach. Adequate ventilation is ensured during the procedure because among other detrimental effects, hypoxia and hypercarbia decrease seizure duration and thus the efficacy of ECT. 10/28/2020 86

Many intravenous anesthetics have been used to induce anesthesia for ECT, including methohexital, thiopental, propofol, and ketamine. Methohexital (0. 75 to 1. 0 mg/kg) is the most commonly used drug for ECT anesthesia and is considered the "gold standard. "Propofol (0. 75 mg/kg) was found to reduce seizure duration, which was believed to decrease the efficacy of ECT. 10/28/2020 87

Thiopental(1. 5 to 2. 5 mg/kg) avoids pain on injection, but it is associated with more hypertension and tachycardia than propofol. 10/28/2020 88

Etomidate may prolong seizures and recovery, but prolongation of the seizure may be useful in patients in whom seizure duration is deemed too short with other agents. Benzodiazepines have anticonvulsant activity and should be avoided before ECT. Ketamine has been demonstrated to not increase seizure length or produce excessive postprocedural agitation. Given the hemodynamic response expected after ECT, ketamine would seem to be a less desirable agent. 10/28/2020 89

Prophylactic medications have been advocated to avoid various side effects of ECT. Transient asystole is rare during ECT, but it may be prevented with anticholinergic pretreatment. Glycopyrrolate is preferred over atropine because glycopyrrolate has no central anticholinergic side effects. In addition, glycopyrrolate is an effective antisialagogue. 10/28/2020 90

Both esmolol and labetalol have been successfully used to control hypertension and tachycardia after ECT. Some evidence has shown that esmolol reduces seizure duration. Routine treatment with esmolol or labetalol is not recommended because the hypertension and tachycardia are usually self-limited, as are premature ventricular contractions. Should treatment be necessary, these drugs can be administered immediately after the stimulus. 10/28/2020 91

Extracorporeal shock wave lithotripsy (ESWL) ESWL used focused shock waves (high intensity pressured wave of short duration) to pulverize renal and ureteral calculi into very small fragment which are then washout by normal urine flow. 10/28/2020 92

1. 2. Electrohydrulic lithotripsy (immersion) Nonimmersion lithotriptor (shock tube) 10/28/2020 93

Consideration No pain Immobile is necessary Immersion cause increase CVP and increase WOB and shallow breathing and rapid. Decrease VC and FRC. Arrhythmia (best is shock delivered 20 mesc after Rwave ) Hypertension or hypotension CHF , MI Hematuria Pulmonary contusion and pancreatitis Flank pain for several days Petechia and soft tissue swelling (1%) No interface with pacemaker 10/28/2020 94

Management of anesthesia Sedation /analgesia GA or RA (T 6) LMA Adequate intravenous fluid for washout 10/28/2020 95

Dental surgery Anesthesia is necessary for very young or mentally patients. CHD (down ) EKG MONITORING IS VERY IMPORTANT BECAUSE TEEDTH AND GUMS ARE VERY INNERVATE. KG 10/28/2020 96

Management of anesthesia Rapid induction and prompt recovery Ketamine IM for induction for IV line STP, POFOL , ETOMIDATE, Sevoflurane Intubation Antiemetic drug Short acting opioid 10/28/2020 97

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