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Chapter 6 Patient Monitors

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					Chapter 6
      Patient Monitors


마취통증의학과 1년차 성 준 경
Outline

 1.   Cardiac monitors
      1) Arterial BP
            ①   Non invasive
            ②   Invasive
      2)   EKG
      3)   Central venous catheterization
      4)   Pulmonary artery catheterization
      5)   Cardiac output
 2.   Pulmonary monitors
      1)   Precordial & esophageal stethoscopes
      2)   Pulse oximetry
      3)   Capnography
      4)   Anesthetic gas analysis
 3.   Neurologic system monitors
      1) Electroencephalography
      2) Evoked potentials
 4.   Miscellaneous monitors
      1) Temperature
      2) Urinary output
      3) Peripheral nerve stimulation
                                                                 Cardiac monitors

Cardiac Monitors : Arterial BP                                           Arterial BP
                                                                         EKG
                                                                         Central venous catheterization
                                                                         Pulmonary artery catheterization
NIBP monitoring                                                          Cardiac output




     • Introduction
        – Mean arterial BP (MAP)
            • Time weighted avg. of arterial pr during a cycle
            • (SBP+2DBP)/3


        – Factors that induces in BP differences
            • Proximity
            • Gravity
            • Lt & Rt
                                                                     Cardiac monitors

Cardiac Monitors : Arterial BP                                               Arterial BP
                                                                             EKG
                                                                             Central venous catheterization
                                                                             Pulmonary artery catheterization
NIBP monitoring                                                              Cardiac output




     • Ix & CIx
        – Absolute Ix in use of any anesthetics
        – Freq: 환자 상태와 수술 종류에 따라 다르지만 대개는
                3-5min 마다 측정
        – Vascular abnormalities(eg, dialysis shunt), IV line 있을 시
          피하는게 좋다.


     • Techniques
        A. Palpation
        B. Doppler probe
        C. Auscultation
        D. Oscillometry
        E. Arterial tonometry
                                                                Cardiac monitors

Cardiac Monitors : Arterial BP                                          Arterial BP
                                                                        EKG
                                                                        Central venous catheterization
                                                                        Pulmonary artery catheterization
NIBP monitoring                                                         Cardiac output




        – A. Palpation
            • Underestimation
            • Unable to check DBP and MAP


        – B. Doppler Probe
            • 위의 Palpation 과 같은 개념이나 촉지 대신
              doppler probe 이용
            • Obese pt, 소아 환자, in shock pt, 에 유용
            • 역시 SBP만 check 가능


        – C. Auscultation
            • Korotkoff sound
                  – Cuff pr를 수축기와 이완기 pr 사이로 맞추면 turbulent flow 가 생기며 특징적인
                    korotkoff sound가 cuff 아래 위치시킨 청진기를 통해 들린다.
            • SBP, DBP, MAP check 가능
                                                             Cardiac monitors

Cardiac Monitors : Arterial BP                                       Arterial BP
                                                                     EKG
                                                                     Central venous catheterization
                                                                     Pulmonary artery catheterization
NIBP monitoring                                                      Cardiac output




        – D. Oscillometry
            • Pulse  Oscillation 유발
                  – Microprocessor가 특정 algorithm을 통해
                    SBP, MAP, DBP 를 계산해 냄.
                  – SBP lv로 cuff pr 가 맞춰졌을때 oscillation 증가
                  – MAP시 oscillation highest
                  – Limitations
                       » 부정맥이 있을시 unreliable할 수 있다.
                       » Cardiopulmonmary bypass시 사용하면 안됨
                  – 전세계적으로 추천되는 NIBP method


        – E. Arterial tonometry
                  – Pr transducer 를 동맥이 지나는 피부위에 위치시킴.
                    A-line과 유사한 waveform을 나타내며 지속적인
                    감시가 가능하다. 하지만 movement artifact에 민감해
                    잦은 calibration을 요하는 단점이 있다.
                                                      Cardiac monitors

Cardiac Monitors : Arterial BP                                Arterial BP
                                                              EKG
                                                              Central venous catheterization
                                                              Pulmonary artery catheterization
NIBP monitoring                                               Cardiac output




     • Clinical consideration
        – BP  organ blood flow
        – But, Flow = Pr/resistance
            • pr높아도 저항도 같이 높아지는 경우 flow 는 늘어나지 않게 된다.
            • 단순히 indicator 로만 봐야 하지 절대적이지는 않다.
        – Proper cuff size




        – Automated BP monitor 사용시 주의사항
            • 너무 잦은 측정, 부정확한 사용 방법
                   Nerve palsy, 정맥으로 주입한 제제의
                    extensive extrarvasation 유발 가능.
                                                             Cardiac monitors

Cardiac Monitors : Arterial BP                                       Arterial BP
                                                                     EKG
                                                                     Central venous catheterization
                                                                     Pulmonary artery catheterization
IBP monitoring                                                       Cardiac output




     • Ix & CIx
         – Ix:
             1.   induced hypotension
             2.   wide BP swing 예상
             3.   end-organ dz로 정확한 BP조절이 필요한 경우
             4.   잦은 ABGA가 필요한 경우


         – CIx
             1. collateral이 없는 곳
             2. preexisting vascular insufficiency 예상되는 경우
                (ex. Raynaud’s phenomenon)
                                                   Cardiac monitors

Cardiac Monitors : Arterial BP                             Arterial BP
                                                           EKG
                                                           Central venous catheterization
                                                           Pulmonary artery catheterization
IBP monitoring                                             Cardiac output




     • Techniques & Cx : Selection of an artery
         – Radial artery
             • Superficial
             • Collateral 존재
             • 5%에서 insufficient collateral flow
                 –   Allen test
                 –   Palpation
                 –   Doppler probe
                 –   Plethysmography
                 –   Pulse oximetry


         – Ulnar artey
             • Deeper & more tortuous
             • 보통은 선택하지 않는다.
                                                                  Cardiac monitors

Cardiac Monitors : Arterial BP                                            Arterial BP
                                                                          EKG
                                                                          Central venous catheterization
                                                                          Pulmonary artery catheterization
IBP monitoring                                                            Cardiac output




         – Brachial artery
             • Antecubital fossa 에 위치
             • Proximity  less distorted waveform
             • Elbow에 위치  kingking 가능


         – Femoral artery
             •   Pseudoaneurysm
             •   Atheroma
             •   Infection
             •   Arterial thrombosis
             •   Aseptic necrosis of the femur head in children
             •   Excellent access
                                                                Cardiac monitors

Cardiac Monitors : Arterial BP                                          Arterial BP
                                                                        EKG
                                                                        Central venous catheterization
                                                                        Pulmonary artery catheterization
IBP monitoring                                                          Cardiac output




         – Dorsalis pedis and posterior tibial arteries
             • Most distorted waveform
             • Modified Allen’s test


         – Axillary artery
             • Hematoma, traumatic cannulation  nerve damage
             • Air, thrombi
                                               Cardiac monitors

Cardiac Monitors : Arterial BP                         Arterial BP
                                                       EKG
                                                       Central venous catheterization
                                                       Pulmonary artery catheterization
IBP monitoring                                         Cardiac output




     • Technique of radial a. cannulation
         – Supination & extension
         – A-line setting
         – Palpation of artery
         – 0.5ml Lidocaine inject directly
           above the artery with 25,27 gauge
           needle
         – 45도로 촉지부위를 향해 advance
         – Blood flashback이 확인되면 needle
           각을 30도 낮추고 1-2mm더 advance.
             Needle 뿐만 아니라 카테터 팁이 확실히
             들어가게 하기 위해.
         – Catheter 삽입
             • 카테터를 “Spinning” 해주는 것이
               도움이 되기도.
         – 3번째, 4번째 손가락으로 동맥위에
             압력을 가함
         – Transducer tubing의 확실한 고정
         – Fixation
                                                                      Cardiac monitors

Cardiac Monitors : Arterial BP                                                Arterial BP
                                                                              EKG
                                                                              Central venous catheterization
                                                                              Pulmonary artery catheterization
IBP monitoring                                                                Cardiac output




     • Complications
         – Examples
                                                –   증가요인
             • Hematoma
                                                     • Prolonged cannulation
             • Bleeding                              • Hyperlipidemia
                  – Unstable fixation                • Repeated insertion attempts
             • Vasospasm                             • Female gender
             • Arterial thrombosis                   • Extraecorporal circulation
             • Embolization of air bubble or         • Use of vasopressors
               thrombi
             • Necrosis of skin overlying the
               catheter
             • Nerve damage
             • Infection
             • Loss of digits
             • Unintentional drug injection
                                                                          Cardiac monitors

Cardiac Monitors : Arterial BP                                                    Arterial BP
                                                                                  EKG
                                                                                  Central venous catheterization
                                                                                  Pulmonary artery catheterization
IBP monitoring                                                                    Cardiac output




     • Clinical consideration
         – Arterial waveform의 정확한 측정을 위해서는 catheter-tubing-transducer sys.이
           arterial waveform의 highest frequency에 적절하게 반응하여야 함.

         – Decrease the frequency of the system (Damping) : addition of tube, stopcocks, air
                  – Overdamping시 : underestimating systolic pr.
                  – Underdamping시 : falsely high SBP

         – Damping coefficient : 0.6 ~ 0.7 이 적절. High pr. Flush test로 구함.
                                                               Cardiac monitors

Cardiac Monitors : Arterial BP                                         Arterial BP
                                                                       EKG
                                                                       Central venous catheterization
                                                                       Pulmonary artery catheterization
IBP monitoring                                                         Cardiac output




         – 정확한 측정값을 위해서는
                 – Tube length 최소화, 불필요한 stopcocks제거, air bubble제거, Low
                   compliance tubing 사용
                 – 정확한 위치에서의 zeroing


         – Arterial waveform을 통해 얻을 수 있는 정보
                 – Upstroke  contractility
                 – Downstroke  pph vascular resistance
                 – 호흡주기동안 size의 과장 및 variation  hypovolemia
                                                          Cardiac monitors

Cardiac Monitors                                                  Arterial BP
                                                                  EKG
                                                                  Central venous catheterization
                                                                  Pulmonary artery catheterization
EKG                                                               Cardiac output




      • Ix & CIx
         – All patients
         – No contraindications


      • Techniques & Cx
         – Lead II
             • Parallel to axis atria  largest P wave
                  – Arrythmia
                  – Inf wall ischemia
         – Lead V5
             • Rearranged three limb lead (Modified V5)
                  – Ant & lat wall ischemia
                                                                             Cardiac monitors

Cardiac Monitors                                                                     Arterial BP
                                                                                     EKG
                                                                                     Central venous catheterization
                                                                                     Pulmonary artery catheterization
EKG                                                                                  Cardiac output




      • Clinical considerations
         – Electrical potential generated by myocardial cells

         – Usage
              •   Heart rate
              •   Arrhythmias
              •   Myocardial ischemia
              •   Conduction abnormalities
              •   Pacemaker malfunction
              •   Electrolyte disturbance

         – Limitation
              • Artifacts
                    – Patient or lead-wire movement
                    – Use of electrocautery
                    – Faulty electrodes
              • Monitoring filters
                    – Lessen artifacts
                    – ST seg distortion  impede the diagnosis of ischemia
                                                                           Cardiac monitors

Cardiac Monitors                                                                   Arterial BP
                                                                                   EKG
                                                                                   Central venous catheterization
                                                                                   Pulmonary artery catheterization
EKG                                                                                Cardiac output




      – Preinduction rhythm strip
          • Intraoperative EKG change 와의 비교

      – ST segment changes
          • ECG must be standardized so that a 1mV signal
            results in a deflection of 10mm on a standard strip monitor
          • WPW synd, BBB, extrinsic pacemaker capture, digoxin therapy
               ST seg 관련 정보의 이용이 불가능 할 수 있다.

      – Myocardial ischemia
          • Criteria
               – Flat or downsloping of ST seg. Depression exceeding 1 mm, 60 or 80 ms after
                   the J point(QRS complex 의 마지막), particularly in conjunction with T wave
                   inversion.
               – ST seg. Elevation with peaked T wave

      – Audible beep
          • Make sure its loud enough!  detect rate & rhythm changes
                                                                           Cardiac monitors

Cardiac Monitors                                                                   Arterial BP
                                                                                   EKG
                                                                                   Central venous catheterization
                                                                                   Pulmonary artery catheterization
Central Venous Catheterization                                                     Cardiac output




     • Ix
         –   CVP monitoring
         –   Fluid administration
         –   Drugs infusion, TPN
         –   Air emboli aspiration
         –   Gain venous access
         –   Insertion of pacing leads


     • CIx
         – Renal cell tumor extension into the RA
         – Fungating TV vegetations
         – Relate to cannulation site & patient condition
              • Ex) anticoagulation tx pt – int jugular vein cannulation
                                                            Cardiac monitors

Cardiac Monitors                                                    Arterial BP
                                                                    EKG
                                                                    Central venous catheterization
                                                                    Pulmonary artery catheterization
Central Venous Catheterization                                      Cardiac output




     • Techniques & Cx
         – SVC와 RA와의 junction 바로 위
         – Intrathoracic pr.에 exposed
             • CVP change according to ventilation method
                  – Spontaneous : 흡기시 CVP 증가 호기시 감소
                  – Controlled : 흡기시 CVP 감소 호기시 증가
         – Should be measured during end expiration
         – Various sites
             • Subclavian
                  – Cx
                         » Pneumothorax
                         » Infection
             • Right int jugular vein
             • Left int jugular vein
                  – Cx
                         » Vascular erosion
                         » Pleural effusion
                         » Chylothorax
                                                                                          Cardiac monitors

Cardiac Monitors                                                                                  Arterial BP
                                                                                                  EKG
                                                                                                  Central venous catheterization
                                                                                                  Pulmonary artery catheterization
Central Venous Catheterization                                                                    Cardiac output




         – Procedure
              •   Trendelenburg position
              •   Full aseptic technique
              •   Triangle
              •   Local anesthetic
              •   Locator needle aspiration
              •   18G thin-wall needle
              •   J-wire
              •   Needle removal & Pliable silastic catheter
              •   Guidewire removal
              •   Catheter tubing connection & Secure
              •   CXR confirmation

         – Caution
            • Cannulation into a artery
                     – Transducing vessel’s pr waveform
                     – Comparing color or PaO2
              • Heart chamber 내로의 migration
              • Should be changed every 72 hrs

         – Risk of central venous cannulation
              •   infection, air or thrombus embolism, arrhythmia, hematoma, pneumothorax, hemothorax,
                  hydrothorax, chylothorax, cardiac perforation, cardiac tamponade, nerve trauma
                                                                   Cardiac monitors

Cardiac Monitors                                                           Arterial BP
                                                                           EKG
                                                                           Central venous catheterization
                                                                           Pulmonary artery catheterization
Central Venous Catheterization                                             Cardiac output




     • Clinical considerations
         – CVP는 RVEDV의 주요 결정인자인 Rt. Atrial pr.와 거의 동일

         – Healthy heart에서 Rt and Lt ventricular performance가 같다고 할 수
           있으므로 CVP로 Lt. ventricular filling을 평가할 수 있다.




             •   a wave : atrial contraction
             •   c wave : ventricular contraction시 TV의 elevation
             •   v wave : TV가 닫혀있을 때 venous return
             •   x descent : systole시의 TV의 downward displacement
             •   y descent : diastole시 TV opening
                                                          Cardiac monitors

Cardiac Monitors                                                  Arterial BP
                                                                  EKG
                                                                  Central venous catheterization
                                                                  Pulmonary artery catheterization
Pulmonary Artery Catheterization                                  Cardiac output




     • Ix
         – ASA에서는 PAC의 사용 적절성은 operation, setting 그리고 환자와
           관련된 risk를 종합적으로 고려해서 결정된다고 하였다.
             • CI, preload, volume status, mixed venous
               vol의 산소화 정도를 알고야 할 때
             • Hemodynamical instability
             • Hemodynamic Cx이 발생할 가능성이
               높은 수술
                                                        Cardiac monitors

Cardiac Monitors                                                Arterial BP
                                                                EKG
                                                                Central venous catheterization
                                                                Pulmonary artery catheterization
Pulmonary Artery Catheterization                                Cardiac output




     • CIx
         – Relative CIx
             • Complete BBB  complete heart block 가능
             • WPW synd, Ebstein malformation
                tachyarrhythmia 발생 가능
             • Pt prone to hypercoagulation
                 thrombus formation
             • Bacteremic pt
                 nidus of infection
                                          Cardiac monitors

Cardiac Monitors                                  Arterial BP
                                                  EKG
                                                  Central venous catheterization
                                                  Pulmonary artery catheterization
Pulmonary Artery Catheterization                  Cardiac output




     • Techniques
         – Swan-Ganz catheter:
             •   110cm long
             •   7.5FR catheter
             •   Polyvinylchloride body
             •   Five lumen
                   –   Thermistor
                   –   Air channel
                   –   Proximal port
                   –   Ventricular port
                   –   Distal port
                                                                          Cardiac monitors

Cardiac Monitors                                                                  Arterial BP
                                                                                  EKG
                                                                                  Central venous catheterization
                                                                                  Pulmonary artery catheterization
Pulmonary Artery Catheterization                                                  Cardiac output




   • 15cm : RA
        – Central venous tracing 확인  ballooning
        – EKG monitoring
   • Sudden increase systolic pr. : RV
   • Sudden increase diastolic pr.(35~45 cm)
         :pulmonary a.
   • Minimal advancement : PAOP

   • Pulmonary a. rupture
        – Pr waveform monitoring  wedge reading (= catheter migration)


   • Difficult case
        –   Deep inspiration
        –   Head up position
        –   Rt lat tilting position
        –   Ice saline injection  stiffen catheter
        –   Inotropic agent  CO증가
                                                      Cardiac monitors

Cardiac Monitors                                              Arterial BP
                                                              EKG
                                                              Central venous catheterization
                                                              Pulmonary artery catheterization
Pulmonary Artery Catheterization                              Cardiac output




     • Cx
         – Hemoptysis
             • May herald pulm a. rupture
             • Double lumen tracheal tube insertion
         – Increases according to duration
             • Should not exceed 72 hr
                                                        Cardiac monitors

Cardiac Monitors                                                Arterial BP
                                                                EKG
                                                                Central venous catheterization
                                                                Pulmonary artery catheterization
Pulmonary Artery Catheterization                                Cardiac output




     • Clinical considerations
         – CVP나 P/E에 비해 보다 정확한 Lt. ventricular preload를 얻을 수 있음

         – Mixed venous blood의 sampling이 가능

         – Air embolism이나 myocardial ischemia의
           detection이 가능

         – Cardiac output측정 가능하여 여러가지
           hemodynamic value 유추 가능

         – PAOP는 LV 의 기능을 간접적으로 볼 수
           있는 indicator이다
                                                                              Cardiac monitors

Cardiac Monitors                                                                      Arterial BP
                                                                                      EKG
                                                                                      Central venous catheterization
                                                                                      Pulmonary artery catheterization
Cardiac Output                                                                        Cardiac output




     •   Ix & CIx
          – PAC를 통해 얻은 정보를 가장 효과적으로 사용하기 위해서는
             CO을 꼭 알아야 함.
          – No contraindications

     •   Techniques & Cx
          – Thermodilution
             • Method
                   –   Fluid injection into RA
                   –   Change in blood temperature (inversely proportionate to CO)
                   –   Thermodilution curve
                   –   Computer processing
             •   Rapid & smooth injection
             •   Exact temperature and volume of the injectant
             •   Precise calibration
             •   Avoidance of electrocautry use
                                                                              Cardiac monitors

Cardiac Monitors                                                                      Arterial BP
                                                                                      EKG
                                                                                      Central venous catheterization
                                                                                      Pulmonary artery catheterization
Cardiac Output                                                                        Cardiac output




         – Ultrasonography
             • TEE
                 – LV filling
                 – Ejection fraction
                 – Contractility
                 – Abnormal wall motion
                      » Detection of myocardial infarction
                 – Limitations
                      » After anesthesia
                      » Increased afterload vs ischemia
                      » Variability of interpretation
                      » Aortic compression in small children
             • Pulse doppler
                 – Velocity of blood flow
                 – TEE (aortic cross sectional area)와 병행
                     SV, CO 산출
             • Continuous-wave suprasternal doppler
                 – Velocity of blood flow
                 – Uses nomogram (age, sex, weight)  estimates aortic cross sectional area
             • Transtracheal doppler
                 – Doppler transducer  aorta diameter, velocity  CO
                                                                         Cardiac monitors

Cardiac Monitors                                                                 Arterial BP
                                                                                 EKG
                                                                                 Central venous catheterization
                                                                                 Pulmonary artery catheterization
Cardiac Output                                                                   Cardiac output




          – Fick principle
              • Oxygen consumption
                 = 동맥과 정맥의 oxygen content 차이 X CO
              • CO =     Oxygen consumption      =   VO2
                       a-v O2 content difference   CaO2-CvO2
              • Oxygen consumption
                   – Differenece between the oxygen content in inspired and expired gas
              • a-v O2 content difference
                   – PAC와 A-line이 있으면 쉽게 구할 수 있다.


     •   Clinical consideration
          – CO  indices reflecting function of circulatory system
          – Difficulty in interpreting pulmonary artery pressure
          – Effective pharmacological manipulation
                                                              Pulmonary monitors

Pulmonary Monitors                                                 Precordial & Esophageal Stethoscopes
                                                                   Pulse Oximetry
                                                                   Capnography
                                                                   Anesthetic Gas Analysis
Precordial & Esophageal Stethoscopes

     • Ix & CIx
        – Replaced by capnography & pulse oximeter
        – Esophageal varix, stricture

     • Techniques & Cx
        – Precordial
        – Esophageal
             • Better breath & heart sound
             • Intubated patient
             • Temperature probe, ECG lead, ultrasound probe, atrial pacemaker
               electrode
                                                                Pulmonary monitors

Pulmonary Monitors                                                   Precordial & Esophageal Stethoscopes
                                                                     Pulse Oximetry
                                                                     Capnography
                                                                     Anesthetic Gas Analysis
Pulse Oximetry

     •   Ix & CIx
          – Mandatory monitor
          – Particularly useful in
               •   Preexisting lung disease
               •   Specific surgery (hiatal hernia repair…)
               •   Special anesthesia (One lung ventilation…)
               •   ROP 가능 neonate
          – No contraindications

     •   Techniques & Cx
          – Sensor
               •   Light source
               •   Light detection
               •   Hb의 red light 와 infrared light 흡수율 차이를 가지고 SpO2 산출
               •   Oxyhemoglobin  absorbs more infrared light (960nm)
               •   Deoxyhemoglobin  absorbs more red light (660nm)
          – Arterial pulsation은 plethysmography를 통해서 확인이 가능하고 이는 non-
            pulsating venous blood나 조직으로부터의 light absorption을 보정해 준다.
                                                                  Pulmonary monitors

Pulmonary Monitors                                                     Precordial & Esophageal Stethoscopes
                                                                       Pulse Oximetry
                                                                       Capnography
                                                                       Anesthetic Gas Analysis
Pulse Oximetry

     • Clinical consideration
         – Limited to detection of gross abnormality
             • Oxygen-Hb dissociation curve에 따라 실제 PaO2가 65mmHg 정도
               밖에 않되는 경우에도 산소포화도는 90이 나올 수 있음.
             • 특별한 폐질환 있거나 FiO2가 낮지 않는 한 bronchial intubation의
               detection이 어려울 수 있다.

         – 대개 oximeter는 low SpO2에서 부정확하며 SaO2와 SpO2 간에는
           delay가 존재한다

         – Purpose
             • Detecting esophageal intubation
             • Monitoring oxygen delivery to vital organs
             • Detecting postoperative pulmonary problems in recovery room
                  – Severe hypoventilation
                  – Bronchospasm
                  – Atelectasis
                                                                                Pulmonary monitors

Pulmonary Monitors                                                                    Precordial & Esophageal Stethoscopes
                                                                                      Pulse Oximetry
                                                                                      Capnography
                                                                                      Anesthetic Gas Analysis
Pulse Oximetry

         – Artifacts
             • CO poisoning  SpO2가 과대 측정 가능
                    – HbO2와 같이 COHb 역시 660nm의 빛 흡수율이 동일

             • Methemoglobinemia  SpO2가 85%근처로 측정됨
                 (lidocaine, nitrates, sulfa제, metoclopramide 등을 사용하는 환자에서 흔히 증가)
                    – Red light와 infrared light의 흡수율 차이가 거의 없다
                         » 실제 SaO2 high  실제보다 낮게 측정
                         » 실제 SaO2 low  실제보다 높게 측정

             • 과도한 외부 조명, 형광등
                    – 형광등의 깜빡임 진동수가 oximeter의 발광 diode의 진동수와 일치 시 SpO2 과대 평가

             • 움직임, malposition sensor (M/C)

             • Methylene blue dye, bluish nail polish
                    – 660nm에서 red light와 근접 흡광도 가지는 푸른색  SpO2 과소평가

             • Low perfusion
                    – Hypothermia, severe anemia, low CO, high systemic vascular resistance  국소혈류
                      감소로 측정 어려움
                         nitroglycerin연고 사용 가능하나 저혈압 악화 가능
                                                                            Pulmonary monitors

Pulmonary Monitors                                                               Precordial & Esophageal Stethoscopes
                                                                                 Pulse Oximetry
                                                                                 Capnography
                                                                                 Anesthetic Gas Analysis
Pulse Oximetry

         – Pulse oximetry technique의 응용
            • Mixed venous blood oxygen saturation (SvO2)
            • Noninvasive brain oximetry (rSO2)
                 – Regional O2 saturation of Hb in brain
                     » All regional microvasculature의 Hb
                     » 정상치 : 약 70%
                 – Cardiac arrest, cerebral embolization, deep hypothermia, severe hypoxia
                    rSO2 감소
                                                                  Pulmonary monitors

Pulmonary Monitors                                                     Precordial & Esophageal Stethoscopes
                                                                       Pulse Oximetry
                                                                       Capnography
                                                                       Anesthetic Gas Analysis
Capnography

    •   Ix & CIx
         – 모든 마취에 유용. 특히 GA
              • 급격한 감소는 sitting craniotomy의 major Cx인 air embolism의 민감한 지표임
         – No contraindications

    •   Techniques & Cx
         – Infrared light absorption technique을 이용
            (이산화탄소의 농도는 4.3um파장의 적외선의 흡수 정도에 비례)
         – Nondiverting (flowthrough)
              • Breathing circuit에 adaptor거치
                 여기를 통과하는 gas를 분석해 모니터에 표시
         – Diverting (aspiration)
             • Breathing circuit 에서 sample line을 통해 monitor내의 sample cell내로 지속적으로
               흡인 분석
             • High aspiration rate(250ml/min) & low-dead-space sampling tubing
                increases sensitivity and lowers lag time
             • Low tidal volume with high aspiration rate (eg. 소아 환자)
                circuit 에서 fresh gas 유입  ETCO2희석
         –  단점  Aspiration tube와 sampling cell내의 water precipitation  obstruction
         – 흡기시 CO2 gas의 detection
              • Expiration valve malfunction
              • exhausted CO2 absorbent
                                                                       Pulmonary monitors

Pulmonary Monitors                                                          Precordial & Esophageal Stethoscopes
                                                                            Pulse Oximetry
                                                                            Capnography
                                                                            Anesthetic Gas Analysis
Capnography

    •   Clinical consideration
         – Esophageal intubation detection에 유용하나 bronchial intubation시에는
           ETCO2만으로는 발견이 힘들다.

         – Sudden cessation  circuit disconnection

         – Rise in ETCO2  malignant hyperthermia 등에서 대사 증가시

         – PaO2와 ETCO2와의 차이
              • 약 2-5mmHg (Alveolar dead space 의미)
              • Decreased Lung perfusion (ex. Air embolism, CO감소, BP 감소)
                   Alveolar dead space 증가
                   Expired CO2의 희석
                   ETCO2 감소
                                                                                   Pulmonary monitors

Pulmonary Monitors                                                                      Precordial & Esophageal Stethoscopes
                                                                                        Pulse Oximetry
                                                                                        Capnography
                                                                                        Anesthetic Gas Analysis
Capnography

  • Various conditions




   •Normal capnograph                                    •Severe COPD
       –Phase I: dead space                                  –No plateau is reached before the next inspiration
       –Phase II: mixture of dead space & alveolar gas       –The gradient between ETCO2 and PaCO2 is increased
       –Phase III: alveolar gas plateau
                                                                       Pulmonary monitors

Pulmonary Monitors                                                           Precordial & Esophageal Stethoscopes
                                                                             Pulse Oximetry
                                                                             Capnography
                                                                             Anesthetic Gas Analysis
Capnography




   •   Spontaneous respiratory effort   •Incompetent expiratory valve or exhausted CO2 absorbent




   •   Incompetent inspiratory valve
                                                                           Pulmonary monitors

Pulmonary Monitors                                                              Precordial & Esophageal Stethoscopes
                                                                                Pulse Oximetry
                                                                                Capnography
                                                                                Anesthetic Gas Analysis
Anesthetic Gas Analysis

     •   Ix
          –   모든 흡입마취제를 이용하는 마취에 유용
          –   No contraindications

     •   Techniques
          ①   mass spectrometry
          ②   Raman spectroscopy
          ③   Infrared spectrophotometry
          ④   piezoelectric crystal (quartz) oscillation

     •   Oxygen analysis : do not absorb infrared light (nonpolar gases)
          ① Galvanic cell
          ② Paramagnetic analysis
          ③ Polarographic electrode

     •   Airway pressure
          –   low peak inspiratory pr.
                ventilator or circuit disconnection
          –   high peak inspiratory pr.
                airway obstruction
Neurological System Monitors                                 Neurological System Monitors
                                                                  Electroencephalography
                                                                  Evoked Potentials

Electroencephalography

     • Ix & CIx
         – Cerebral cortex cell에 의해 생성된 electrical potential의 recording
         – Cerebrovascular surgery중 cerebral oxygenation monitoring을 위해
           종종 사용됨.
         – Monitoring of depth of anesthesia만을 위해서는 사용 안 함
         – No contraindications
     • Techniques & Cx
         – International 10-20 system (Montage)
            : 각 electrode사이의 electrical potency
             차이를 여과, 증폭하여 표시함.
Neurological System Monitors                                                    Neurological System Monitors
                                                                                      Electroencephalography
                                                                                      Evoked Potentials

Electroencephalography

     •   Clinical considerations
          – EEG change during ischemia  high frequency activity
               • Mimicked by hypothermia, anesthetic agents, electrolyte disturbance, marked
                 hypocapnia
               • Detection of this change  immediate review of possible causes of cerebral
                 ischemia before irreversible brain damage occurs
          – BIS: correlates wit depth of anesthesia
               • Sedation : 65-85
               • GA : 40-65
               • Reduce patients awareness
                 during anesthesia
               • Reduce resource utilization
               • Facilitate fast wake up time
                  shorter stay in recovery room
Neurological System Monitors                                        Neurological System Monitors
                                                                         Electroencephalography
                                                                         Evoked Potentials

Evoked Potentials

     • Ix & CIx
         – Surgical procedures associated with possible neurological injury
         – Limited by availability of monitoring sites, equipment, and trained
           personnel


     • Techniques & Cx
         – Sensory/motor stimulation electrophysiological response
             • Brain stem auditor evoked responses (BAERs)
             • Somatosensory-evoked potentials (SEPs)
             • Motor-evoked potentials (MEPs)
         – 파형은 감각기관계의 해부 생리학적 구조 또는 상태에 의해 형성
             • 유발전위 파형이 제대로 유발 형성되는지 여부
                                                                   각각의 감각기관계의 신경
             • 유발된다 하더라도 자극 후 유발 특정파형이                             생리학적 이상 유무를 평가
               나타나는데 걸리는 시간이 지연되었는지 여부
Neurological System Monitors                                             Neurological System Monitors
                                                                              Electroencephalography
                                                                              Evoked Potentials

Evoked Potentials

     • Clinical considerations
         – Altered by many variables (anesthetics)
             • Balanced anesthetic techniques
             • Avoidance or constant low dose usage of volatile agents
         – Persistent obliteration of EPs
            Predictive of postoperative neurologic deficit
                                                                              Miscellaneous Monitors
Miscellaneous Monitors                                                             Temperature
                                                                                   Urinary Output
                                                                                   Peripheral Nerve Stimulation
Temperature

     •   Ix & CIx
          – Advised in every patients undergoing general anesthesia over 15 min.
          – No contraindications

     •   Techniques & Cx
          – Thermistor: semiconductor
          – Thermocouple: circuit of two dissimilar metals joined
          – Cx: trauma caused by the probes (ex. Tympanic membrane, rectal)

     •   Clinical considerations
          – Hypothermia
               • Body temperature <36
               • Metabolic oxygen requirements
                  protective during times of
                     cerebral or cardiac ischemia
               • Deleterious physiological effects
                 of unintentional hypothermia
                  ( Increases with 고령, 복부수술, 긴 수술,
                      낮은 수술 방 온도)
               • Post-op shivering
                   – 5배까지 oxygen consumption         SaO2   , 심근허혈, 협심증 증가와 관련
                   – Tx: Meperidine 25mg
                   – Maintain normothermia during op.
                                                                             Miscellaneous Monitors
Miscellaneous Monitors                                                            Temperature
                                                                                  Urinary Output
                                                                                  Peripheral Nerve Stimulation
Temperature

        – Core temperature
              • Phase I: 전신 마취 후 첫 1시간. 1~2도 하강
              • Phase II: more gradual decrease during 3~4th hour
              • Phase III: point of steady state or equilibrium
                             (heat loss = metabolic heat production)


        – Hypothermia 기전
           • Initial decrease in temperature
                 Redistribution of heat from warm central compartment to cooler
                   peripheral tissues (anesthetic–induced vasodilators)
              • 전신마취시,
                 interfere hypothalmic function  inhibit central thermoregulation
              • 국소마취시 ( Spinal & epidural )
                 vasodilation (phase I 촉진),
                  altered perception of blocked dermatome (phase II 촉진)
                                                                                               Miscellaneous Monitors
Miscellaneous Monitors                                                                              Temperature
                                                                                                    Urinary Output
                                                                                                    Peripheral Nerve Stimulation
Temperature

        – Solutions for hypothermia
              • Pre-warming (convective forced-air warming blanket)
                 중심-말초간 체온 차이를 없앰으로써 phase I hypothermia를 예방
              • Forced-air warming blanket, warm water blanket, heated humidification of inspired gas,
                warming of IV fluid, raising ambient OR temperature  phase II hypothermia 예방
              • Heated cotton blankets (space blankets)  전신을 덮지 않는 이상 little effect

        – Monitoring sites (advantages & disadvantages)
              • Tympanic membrane
                     –   Reflects brain temperatture
                     –   Trauma
              • Rectal temperature
                     –   Slow response
              • Nasopharyngeal probes
                     –   Epistaxis
              •   Thermister on PAC
              •   Axillary temperature: skin perfusion
              •   Liquid crystal adhesive strips placed on skin: inadequate
              •   Esophageal temperature sensor
                     –   Best combination of economy, performance, and safety
                     –   Should be positioned behind the heart in the lower 1/3 of esophagus
                                                                                            Miscellaneous Monitors
Miscellaneous Monitors                                                                           Temperature
                                                                                                 Urinary Output
                                                                                                 Peripheral Nerve Stimulation
Urinary Output

     •   Ix & CIx
          –   Congestive heart failure / renal failure / advanced hepatic disease / shock
              Cardiac surgery / aortic or renal vascular surgery / craniotomy / major
              abdominal surgery / large fluid shift가 예상되는 수술 / 긴 수술
          –   감염의 위험이 높은 환자에게선 주의

     •   Techniques & Cx
          – Urine reflux와 infection risk의 최소화를 위해서 chamber는 항상 방광보다
            낮은 곳에 위치시켜야 함
          – Cx: Urethral trauma, infection, rapid decompression of a distended bladder 
            Hypotension유발 가능

     •   Clinical considerations
          – Foley catheter
                • Thermister 부착 가능
                  (urinary output 이 높게 유지되는 한 core temp 정확하게 반영)
                • Urometer: electronically monitor and record U/O & temp.
          – Urine output
                • Reflection of kidney perfusion & function
                • Renal , cardiovascular, and fluid volume status
          – Oliguria
                • Output less than 0.5mL/kg/hr (arbitrary)
                • Function of the patient’s concentrating ability and osmotic load
                                                                            Miscellaneous Monitors
Miscellaneous Monitors                                                           Temperature
                                                                                 Urinary Output
                                                                                 Peripheral Nerve Stimulation
Peripheral Nerve Stimulation

     •   Ix & CIx
          – Variation in patient sensitivity to neuromuscular blocking agents
          – Assessing paralysis in rapid sequence induction or continuous infusion of
            short acting neuromuscular blocking agents
          – Regional anesthesia  locate nerve to be blocked
          – No contraindications

     •   Techniques & Cx
          – EKG silver chloride pad / subcutaneous needle
             evoked mechanical or electrical response
          – Electromyography < Visual or tactile observation
          – Ulnar nerve stimulation  adductor pollicis m.
          – Facial nerve stimulation  orbicularis oculi
          – Direct muscle simulation should be avoided
          – Cx is limited to skin irritation and abrasion at
            the site of electrode attachment
                                                                         Miscellaneous Monitors
Miscellaneous Monitors                                                        Temperature
                                                                              Urinary Output
                                                                              Peripheral Nerve Stimulation
Peripheral Nerve Stimulation

     • Clinical considerations
         – 각각의 muscle group들은 근이완제에 대한 민감도가 다르기
           때문에 peripheral nerve stimulation이 이완을 원하는 근육의 direct
           observation을 대체할 수는 없다.
             • Ex) diaphragm, rectus abdominus, laryngeal adductor, orbicularis
               oculi등의 근육들은 adductor pollicis m. 보다 근이완에서 빨리
               회복한다.


         – Indication of adequate recovery
             • 5초 이상 head lift 유지
             • 적어도 25cm H2O 이상의 insp. Pr. 를 만들수 있을 때
             • forceful hand grip
Thank you for your attention.

				
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