Basics of mechanical ventilation
- 1. BASICS OF MECHANICAL VENTILATION DR. ROHAN MALAKAR 2ND YEAR DTCD PGT DEPARTMENT OF RESPIRATORY MEDICINE MEDICAL COLLEGE KOLKATA
- 2. OBJECTIVES o INDICATIONS OF VENTILATION o MODES OF VENTILATION o VENTILATION SETTINGS o ALARMS o VENTILATOR GRAPHICS o CASE ORIENTED ELASTRATION
- 3. INDICATIONS OF MECHANICAL VENTILATION HYPOXIC RESPIRATORY FAILURE (FIGHTERS IN AGONY) HYPERCAPNIC RESPIRATORY FAILURE(THE LAZY ONES) PROTECTION OF AIRWAYS AGAINST ASPIRATION SURGICAL PROCEDURE UNDER GA APNEA(THE SILENT ONES) CONTRAINDICATIONS UNTREATED PNEUMOTHORAX(ABSOLUTE) INFORMED CONSENT (RELATIVE) MEDICAL FUTILITY
- 4. MODES OF VENTILATION CONTROLLED MODE VENTILATION(VOLUME/PRESSURE) ASSIST CONTROLLED(VOLUME/PRESSURE) SYNCHRONIZED INTERMITTENT MANDATORY VENTILATION(SIMV) PRESSURE REGULATED VOLUME CONTROL(PRVC) AIRWAY PRESSURE RELEASE VENTILATION(APRV) PRESSURE SUPPORT VENTILATION
- 5. THE PULL UP STORY NO EFFORT FROM TRAINEE SO TRAINER GIVES FULL SUPPORT TO COMPLETE THE EXERCISE ONLY A MINUTE INTEND FROM TRAINEE AND TRAINER GIVES FULL SUPPORT TO COMPLETE THE EXERCISE 2/3-3/4 EFFORT COMES FROM TRAINEE AND TRAINER GIVES REST OF THE SUPPORT TO COMPLETE THE PROCESS 1.CMV 2.ASSIST CONTROL 3.PSV
- 6. PHASE VARIABLES(the switch story) B A= TRIGGER C B= CYCLE TIME,PRESSURE,FLOW PRESSURE,FLOW,VOLUME ,TIME A C= LIMIT PRESSURE,FLOW
- 10. CONTROL MODE VENTILATION VENTILATOR DELIVERS PRESET TIDAL VOLUME(OR PRESSURE) AT A TIME TRIGGERED(PRESET)RESPIRATORY RATE AS THE VENTILATOR CONTROLS BOTH TIDAL VOLUME(PRESSURE) AND RR,THUS VENTILATOR CONTROLS THE MINUTE VOLUME PATIENT CAN’T BREATH SPONTENEOUSLY SUITABLE ONLY WHEN PATIENT HAS NO BREATHING EFFORT OR KNOCKED DOWN WITH SEDATION + PARALYSING AGENT BUT.. CAN’T BE USED DURING WEANING IF PATIENT IS AWAKE.. ASYNCHRONY EXPECTED..AND EVENTUALLY ACID BASE BALANCE HAMPERD
- 11. ASSIST CONTROL VENTILATION A SET TIDAL VOLUME AND FLOW(ACVC)OR SET PRESSURE AND TIME(ACPC)IS DELIVERED AT A SET RR ADDITIONAL VENTILATOR BREATHS ARE GIVEN IF TRIGGERED BY THE PATIENT TIDAL VOLUME OF EACH BREATH FROM THE MACHINE IS THE SAME WHEATHER IT IS ASSISTED OR CONTROL MINIMUM BREATH RATE IS GUARANTEED ASYNCHRONY IS TAKEN CARE OF TO SOME EXTENT WOB IS RFEDUCED AS EVERY BREATH IS ASSISTED AND FIXED Vt IS ASSURED BUT… HYPERVENTILATION…ACID BASE IMBALANCE NATURAL BREATHS ARE NOT ALLOWED BREATH STACKING HIGH VOLUME
- 12. SYNCHRONIZED INTERMITTENT MANDATORY VENTILATION VENTILATOR DELIVERS EITHER PATIENT TRIGGERED ASSISTED BREATH OR TIME TRIGGERED MANDATORY BREATH IN A SYNCHRONIZED FASHION SO AS TO AVOID BREATH STACKING IF THE PATIENT BREATHES IN BETWEEN THE MANDATORY BREATHS THE VENTILATOR WILL ALLOW TO BREATHE A NORMAL BREATH BY OPENING THE DEMAND(INSPIRATORY) VALVE BUT NOT OFFERING ANY INSPIRATORY ASSISTANCE SO 3 TYPES OF BREATH…..1.MACHINE GENERATED CONTROLLED VENTILATION 2.PATIENT INITIATED ASSISTED VENTILATION 3.UNASSISTED SPONTENEOUS BREATH A. WHEN PATIENT INSPIRATORY EFFORT AT GREEN ZONE ..2 OCCURS SYNCHRONIZATION WINDOW B. WHEN RESPIRATORY EFFORT AT RED ZONE..COUNTED AS MANDATORY BREATH C.IF PATIENT BREATHS OUTSIDE THE TWO ZONES ,MACHINE WILL ALLOW THAT SPONT BREATH TIME TRIGGERING
- 13. SIMV CONTD… IT ALLOWS PATIENTS TO ASSUME A PORTION OF THEIR VENTILATORY DRIVE….WEANING IS POSSIBLE…. GREATER WOB THAN A/C MODES AND THEREFORE SOME MAY NOT CONSIDER AS INITIAL VENTILATOR MODE FRIENDLY CARDIOPULMONARY INTERACTION….NEGETIVE INSPIRATORY PRESSURE GENERATED BY SPONTENEOUS BREATHING INCREASED VENIUS RETURN INCREASED CARDIAC OUTPUT
- 18. TIDAL VOLUME AMOUNT TO BE DELIVERED WITH EACH BREATH 6-8ml/KG BW ARDS 6ml/KG AVOID VERY HIGH Vt TO PREVENT VOLUME TRAUMA Vt IS FIXED IN ACVC/V-CMV MODE Vt IS VARIABLE IN ACPC/P-CMV MODE PREDICTED BODY WEIGHT (Height in inches) MALE 50+2.3 FEMALE 45.5+2.3
- 19. RESPIRATORY RATE SET HIGH RR IN RESPIRATORY ACIDOSIS SET LOW RR IN RESPIRATORY ALKALOSIS SET NORMAL RR IN NEUROLOGICAL ISSUES OR POST OP CASES MONITOR PH PCO2 AIR TRAPPING
- 20. MINUTE VENTILATION NORMAL 6-8L/MIN TO WASH OUT INCREASED PCO2 ….INCREASE THE MINUTE VENTILATION IN RESPIRATORY ALKALOSIS REDUCE MINUTE VENTILATION AS PER REQUIREMENT REPEAT ABG AS PER REQIREMENT TO KEEP AN EYE ON PH PCO2 PO2
- 21. PRESSURE PRESSURE(Pi) IS FIXED IN ACPC AND P-CMV MODE Pi VARIABLE IN ACVC AND V-CMV MODE MONITOR Ppeak/PIP…COMBINATION OF RESISTANCE AND COMPLIANCE(KEEP <40-45cm of H2O) Pplat…..MEASURES LUNG COMPLIANCE(target <30cm of H2O)
- 22. FLOW MAXIMUM FLOW DELIVERED BY THE VENTILATOR DURING INSPIRATION NORMAL PEAK FLOW RATE 60L/MIN HIGHER RATE IS REQUIRED IN ACIDOTIC PATIENT OAD INSUFFICIENT PEAK FLOW RATE WILL CAUSE AIR HUNGER…..DYSPNEA FLOW PATTERN CAN BE CHOSEN IN VCV (SQUARE WAVE AND RAMP WAVE) IN PCV ALWAYS RAMP WAVE RAMP WAVE IS PREFERRED DISTRIBUTE VENTILATION MORE EVENLY IN OAD REDUCES Ppeak,DEAD SPACE
- 23. INSPIRATORY TIME (Ti) AND I:E RATIO NORMAL ..1:2-2.5 ARDS 1:1/1:1.5….(INVERSE VENTILATION AT TIMES) OAD…1:3 OR HIGHER MONITOR MVe PH PCO2 PO2
- 24. FiO2 LOWEST POSSIBLE FiO2 TO MEET OXYGENATION GOALS SHOULD BE USED ALWAYS KEEP IN MIND REGARDING OXYGEN TOXICITY KEEP FiO2 IN SUCH A LEVEL SO THAT SPO2 IN MONITOR IS NOT MORE THAN 99%(AS MONITOR WILL SHOW SPO2 100 BOTH THE CASES WHEN PO2 IS 90 AS WELL AS WHEN PO2 IS 160..SO WITH SPO2 100% OXYGEN TOXICITY WILL NOT BE TAKEN CARED OF) TARGET SPO2 88-92% IN COPD PATIENTS…SO KEEP FiO2 IN SUCH A WAY
- 25. PEEP IT REINFLATES THE COLLAPSED ALVEOLI AND SUPPORTS ALVEOLAR INFLATION DURING EXHALATION USEFUL TO TREAT REFRACTORY HYPOXEMIA INITIAL SET UP AT 5cm OF H2O ALVEOLAR INFLATION INCRERASED FRC IMPROVES VENTILATION INCREASES V/Q IMPROVES OXYGENATION DECREASES WOB COMPLICATIONS….. REDUCED VENOUS RETURN ..HENCE REDUCED CO…HENCE REDUCE BP BAROTRAUMA INCREASED ICT
- 27. When you see this message It means Do This O2 SENSOR Background checks have detected a problem with the O2 sensor. O2 sensor is out of calibration or has failed. Press 100% O2 CAL; replace or disable the sensor. PCIRC (High circuit pressure) The O2 % measured during any phase of a breath cycle is 7% (12% during the first hour of operation) or more above the O2 % setting for at least 30 seconds. (These percentages increase by 5% for four minutes following a decrease in the O2 % setting.) Check patient, patient circuit and endotracheal tube. O2 % (High delivered O2 %) The O2 % measured during any phase of a breath cycle is 7% (12% during the first hour of operation) or more above the O2 % setting for at least 30 seconds. (These percentages increase by 5% for four minutes following a decrease in the O2 % setting.) Check patient, air and oxygen supplies, oxygen analyzer and ventilator. VTE (High exhaled tidal volume) The patient’s exhaled tidal volume for any breath is equal to or greater than the set limit. Check patient and settings. Consider whether the patient’s compliance or resistance has changed. V . E TOT (High exhaled total minute volume) The patient’s expiratory minute volume is equal to or greater than the set limit. Check patient and settings.
- 28. When you see this message It means Do This V . ti SPONT Alarm The delivered volume of any tube compensated (TC) breath is equal to or greater than the inspired tidal volume limit. Ventilator transitions to exhalation. Check patient. Check for leaks, tube type/I.D. setting. f TOT (High respiratory rate) The breath rate from all breaths is greater than or equal to the set limit. Check patient and settings. PVENT (High internal ventilator pressure) The inspiratory pressure transducer has measured a pressure of at least 100 cm H2 O. Active only during volume-controlled breaths. Ventilator transitions to exhalation. Reduced tidal volume likely. Check patient. Obtain alternate ventilation. Remove ventilator from use and contact service. PCOMP The target pressure of a tube compensated (TC) breath equals the Pcirc limit. This limit is equal to the setting of Ppeak. Inspiration pressure is limited during this alarm. Check patient. Check for leaks, tube type/I.D. setting INOPERATIVE BATTERY BPS is installed but not functioning. Contact service. INSPIRATION TOO LONG IBW-based inspiratory time for a spontaneous breath exceeds ventilatorset limit. Check patient. Check for leaks.
- 29. When you see this message It means Do This LOSS OF POWER The ventilator power switch is on and there is insufficient power from the AC supply and the BPS. There may not be a visual indicator for this alarm, but an independent audio alarm sounds for at least 120 seconds. Obtain alternate ventilation. LOW AC POWER Mains ac power has dropped below 80% of nominal voltage for at least one second. Warns that AC power has dropped significantly, and that a more severe power drop may be imminent. The ventilator turns off the compressor (if installed), and otherwise operates normally Check integrity of connection to AC power. Check AC power supply LOW BATTERY The BPS has less than approximately two minutes of operational time remaining. Replace BPS or allow it to recharge during normal ventilator operation.
- 30. When you see this message It means Do This ↓O2 % (Low delivered O2 %) The O2 % measured during any phase of a breath cycle is 7% (12% during the first hour of operation) or more below the O2 % setting for at least 30 seconds, or below 18%. (These percentages increase by 5% for four minutes following an increase in the O2 % setting.) Check patient, air and oxygen supplies, oxygen analyzer and ventilator. Calibrate oxygen sensor (press 100% O2/CAL 2 min key). ↓VTE MAND (Low exhaled mandatory tidal volume) The patient’s exhaled mandatory tidal volume is less than or equal to the set limit. Check patient. Check for leaks or changes in the patient’s resistance or compliance. ↓VTE SPONT (Low exhaled spontaneous tidal volume) The patient’s exhaled spontaneous tidal volume is less than or equal to the set limit. Check patient and settings. ↓V . E TOT (Low exhaled total minute volume) The minute volume for all breaths is less than or equal to the set limit. Check patient and settings. NO AIR SUPPLY Air supply pressure is less than the minimum required pressure for correct ventilator operation throughout its range of flows. Accurate O2 % delivery may be compromised. You cannot set or disable the NO AIR SUPPLY alarm. Check patient and air source. Obtain alternate ventilation.
- 31. When you see this message It means Do This NO O2 supply Oxygen supply pressure is less than the minimum required pressure for correct ventilator operation throughout its range of flows. Accurate O2 % delivery may be compromised. You cannot set or disable the NO O2 SUPPLY alarm. Check patient and oxygen source. Obtain alternate ventilation. PROCEDURE ERROR Patient attached before ventilator startup is complete. Safety ventilation is active. Provide alternate ventilation. Complete ventilator startup procedure. SEVERE OCCLUSION Patient circuit is severely occluded. Check patient. Obtain alternate ventilation if necessary. Check patient circuit for crimps, blocked filter. If problem persists, remove ventilator from use and contact service.
- 32. When you see this message It means Do This AC POWER LOSS The power switch is ON, AC power is not available, and the ventilator is being powered by the backup power source (BPS). Prepare for power loss. Obtain alternate ventilation. Check integrity of AC power source. Contact service if necessary. APNEA The set apnea interval has elapsed without the ventilator, patient or operator triggering a breath. Check patient and settings CIRCUIT DISCONNECT There is a disconnection in the patient circuit before the patient wye or patient disconnect is detected following power restoration from an unintentional power loss with the power switch ON. Check patient. Reconnect patient circuit. Press ALARM RESET. COMPRESSOR INOPERATIVE Compressor cannot maintain sufficient supply pressure. Check patient. Obtain alternate ventilation. Remove ventilator from use and contact service DEVICE ALERT A background test or power on self-test (POST) has detected a problem. Check patient. If prompted to do so, obtain alternate ventilation or contact service.
- 33. VENTILATOR GRAPHICS/WAVEFORMS SCALARS PLOT PRESSURE/VOLUME/FLOW AGAINST TIME SO TIME IS IN THE X AXIS LOOPS PLOT PRERSSURE/VOLUME/FLOW AGAINST EACH OTHER SO NO TIME COMPONENT
- 34. WAVEFORMS contd.. SIX BASIC WAVEFORMS SQUARE ASCENDING RAMP DESCENDING RAMP SINUSOIDAL/SINE WAVES EXPONENTIAL RISING EXPONENTIAL DECAYING
- 35. FLOW VS TIME SCALAR
- 36. PRESSURE VS TIME SCALAR
- 37. VOLUME VS TIME
- 38. VOLUME FLOW LOOP
- 40. THE ANIMAL STORY… COP CRITICAL OPENING PRESSURE LIP LOWER INFLATION POINT UIP UPPER INFLATION POINT CCP CRITICAL CLOSING PRESSURE FISH TAIL WILL TELL A TALE.. THAT PATIENT IS IS HAVING INCREASED WOB…EITHER PATIENT IS FLOW HUNGRY OR CAN’T TRIGGER THE VENT SOLUTION: INCREASE FLOW DECREASE TRIGGER
- 48. LOWER LIMB DOEST RETURN TO BASELINE AIR TRAPPING IS GOING ON PCO2 RISE ANTICIPATED SOLUTION DO ABG ADJUST I:E RATIO
- 49. RAGGED BORDER INDICATES SMOOTH FLOW IS HAMPERED DURING THE CYCLE SECRETION EXCESS WATER ACUMULATION SUCTION IS REQUIRED
- 50. BREATH STACKING REFERS TO UNINTENDED HIGH TIDAL VOLUME THAT OCCUR AS A CONSEQUENCES OF INCOMPLETE EXHALATION BETWEEN CONSECUTIVE INSPIRATORY CYCLES DELIVERED BY THE MACHINE SOLUTION SEDATE AND PARALYSE THE PATIENT AND LET THE ISSUE RESOLVE
- 51. CASE WISE INITIAL SETTINGS TYPE II RESPIRATORY FAILURE GOAL IS TO WASHOUT PCO2 PUT ON CMV MODE..KONCK THE PATIENT DOWN EYE ON VeTOT..MORE VeTOT..MORE CO2 WASHOUT MORE EXPERITORY TIME,MORE RR TYPE I RESPITATORY FAILURE GOAL IS TO CORRECT HYPOXEMIA KNOCK DOWN AND PUT ON CONTROL MODE EYE ON SP02. WORK WITH FiO2,VTi AND FLOW PEEP NORMAL I:E RATIO OR MORE Ti NORMAL RR.
- 52. ARDS
- 53. THE STORY…NOT TO FORGET ELECTIVE VENTILATION IS FAR BETTER THAN CRASH VENTILATION…OUTCOME BETTER USE ANTIEMETICS,ANTISECRETORY AGENT,SEDATIVES,INDUCING AND PARALYSING AGENTS PROPERLY EXTUBATION IS A SLOW AND STEADY PROCESS..HURRIED EXTUBATION MAY LEAD TO EXTUBATION FAILURE IF YOU ARE CONFIRMED OF A ET TUBE BLOCK..EXTUBATE STAT(EVEN IF YOU DON’T KNOW INTUBATION)..DONT TRY TO CHANGE THE TUBE WITH BOUGIE.. IF YOU FIND ANY ABNORMAL PATIENT DATA…DON’T FORGET TO CHECK YOUR VENTILATOR AND TUBINGS AND HME FILTER…AS IT’S A MACHINE AFTERALL VENTILATED PATIENT REQUIRES 24HRS CONTINIOUS MONITORING…RE-ASSESMENT…RE-ADJUSTMENT OF SETTINGS..REPLANNING BEFORE EXTUBATION ALWAYS KEEP A VIGIL AT THE ROOT CAUSE OF VENTILATION,IF ROOT CAUSE IS NOT TAKEN CARED OF,THEN EXTUBATION WILL BE A FAILURE DOWN THE LINE
- 54. THANK YOU…