Renaissance in Anesthesia Machine Safety The Modern Anesthesia Machine (Workstation) & Anesthesia Delivery Unit (ADU): Improved Safety Features Charles G. McCombs, Jr. CRNA, BSA

Morton’s Ether Inhaler (1846) Wm. T. G. Morton For centuries, man searched for substances to relieve pain. But it wasn’t until the mid 19th century that substances such as diethyl ether and chloroform were shown to be capable of relieving surgical pain. In 1846, Wm T.G. Morton successfully anesthetized Morton’s Ether Inhaler (1846)

Civil War Era Anesthesia Chisholm Chloroform Inhaler Ether Cone Civil War Era Anesthesia

The Teter Anesthesia Machine (1903) Pioneers The Teter Anesthesia Machine (1903) 1903 – Charles K. Teter, DDS Jay Heidbrink DDS Samuel S. White DDS 1917 - Dr. Henry Edmund Gaskin Boyle First Anesthesia Machine (Boyle Machine) British Anesthetist Dr. Henry Edmund Gaskin Boyle is credited (by whom is unknown) with inventing the first anesthesia machine in 1917 known as the The Boyle Machine The Teter machine – developed a machine to deliver compressed N2O, O2 The Boyle Machine (1917)

No. American Drager 2A (c1986) Ohio Medical (1966) No. American Drager 2A (c1986)

1979 American National Standards Institute (ANSI) ANSI Z-79 Committee Machine Standards Failsafe Valve & Alarm Vaporizer Lockout DISS Connections PISS Connections Active Regulators Legible & Visible Gauges 1979 American National Standards Institute (ANSI)

1988 American Society For Testing and Materials (ASTM) ASTM F-29 Committee ASTM F1850-00 Preuse Checkout Procedures Proportioning Device Concentration Calibrated Vaporizers Integral O2 Analyzer Master Switch Enabled Alarms Hierarchical Alarm Prioritization 1988 American Society For Testing and Materials (ASTM)

The Modern Anesthesia Workstation No. American Drager Julian Datex Ohmeda (GE Health Care) Aestiva 5 Fabius GS, Apollo, and Narkomed 6000 (Divan) piston ventilators S/5 ADU incorporates Electronically controlled Aladdin Cassettes The Modern Anesthesia Workstation

The Modern Anesthesia Workstation GE Health Care ADU/5 ADU/5 Aladin Cassette Vaporizers The Modern Anesthesia Workstation

“Brain Damage & Death Related to Anesthesia Machines” (Caplan, 1997) RA Caplan (1997) - Study of 3791 Closed Anesthesia Claims (1962 – 1991) 72 claims related gas delivery system Claim frequency decreased from 2.2% to 1.2% from 1985 – 1991 Pure equipment failures were rare Rate of equipment misuse, 3 x higher than pure failures 76% of claims – Death or Brain Damage 78% of injuries could have been prevented by better monitoring Caplan,RA, Visica, MF, Posner, KL, Cheney, FW Adverse anesthetic outcomes arising from gas delivery equipment; a close claims analysis. Anesthesiology 1997;87:741-8

Specific Damaging Events (Caplan, 1997) Breathing Circuit (39%) - The #1 Culprit Caused 70% of the incidence of death & Brain Damage Most Frequent Circuit Event – Disconnects or misconnects leading to hypoventilation or barotrauma Vaporizers (21%) Overdose or awareness Gas analysis or cerebral monitoring may have prevented Ventilators (17%) Improper activation or excessive Vt /Inspiratory pressure

Specific Damaging Events (Caplan, 1997) High Pressure Gas Supplies (11%) – direct connection to respiratory system w/o proper decompression Human Error – 3 times more common than failure of equipment Failure to precheck Unfamiliarity with equipment Lack of Vigilance Unauthorized repair or “jury rigging” Caplan,RA, Visica, MF, Posner, KL, Cheney, FW Adverse anesthetic outcomes arising from gas delivery equipment; a close claims analysis. Anesthesiology 1997;87:741-8

Conventional v.s. Modern Anesthesia Machines Conventional Machines Modern Machines North American Drager - Narkomed Series (2A, 2B, 3, 4, & GS) Ohmeda - Modulus & Excel Drager Medical – Fabius GS v1.3, Julian, Apollo, Narkomed 6400 Datex-Ohmeda – Aestiva/5 (assuming 7900 ventilator), Anesthesia Delivery Unit (ADU) (assuming S/5 monitor system)

Limitations of the Conventional Machine Numerous External Connections Barotrauma Protection (Manually Set Pressure Limiters) Vaporizer Risks Lack of Advanced Ventilator Features Inaccurate Delivery of Set Tidal Volumes (Vt) Manual Preuse Checkout Procedures Lack of Integrated Information Systems Poor Low-Flow Adaptation Compressed Gas Consumption

The Modern Machine Addresses Limitations Reduced External Connections Internal Modular Design (Aestiva/5) or Manifold Components (Julian) Electronically Controlled PEEP and Open Reservoir Scavenging

Electronic Vaporizer Cassettes ADU, Aladin Cassettes (GE Healthcare) Electronically Control & Measure Vaporization Eliminates need for multiple vaporizers Color Coded, magnetically labeled Agent delivery reported to Information Management System (IMS). Overfill protection Automatically leak tested Check valve protection for bypass circuit

Piston Driven Ventilators (Drager Medical) Fabius GS Narkomed 6400 Divan

Modern Ventilators “Conventional” Dual Circuit, Pneumatic Drive 7900 “SmartVent” (GE Healthcare) Single Circuit Electronic Piston Drive Divan or Fabius GS (Drager Medical) Allows Flexibility in ventilation Pressure Control Ventilation (PCV) Volume Control Ventilation (VCV) Pressure Support Ventilation (PSV) Synchronized Intermittent Mandatory Ventilation (SIMV-Vol & SIMV-PC)

Modern Ventilators Methods to Assure Accuracy in Delivery of set Tidal Volumes (Vt) Fresh Gas Decoupling (FGD) Compliance Testing and Compensation Leak Testing/Measurement and Reporting Location and Electronic Activation of PEEP Electronic Settings Reduce Operator Error One-step activation of Control Mode Ventilation (CMV)

Automated Checkout Procedures and Monitoring User cannot Circumvent Multitude of Surveillance Alarms Critical Systems Checked Computer Circuit Loops Flow Meters Pressure Sensors Piston Drive Gears Coordination /operation of Valves Compliance Compensation Fresh Gas Control Display of Ventilation & Airway Pressures The operator can not test these tolerances manually by conventional checkout procedures. While the machine can be used with abbreviated test procedures for emergencies, eventually the meachine can not be used till retested.

Information Management Systems (IMS) Integrated Systems exceed ASTM Standards Integrated Physiological and Respiratory Monitoring Data Digital Fresh Gas & Volatile Agent Flow Data (Inspired & Expired Concentration) Data Exported to Anesthetic Record Data MAY be Exported to other Demographic and Financial Records

New Machines; New Concerns Operator Learning Curve - even less understanding of machine functions) Over reliance on Technology – Are you sure it will tell you all that fails? Dependence on Electricity - How does your machine function in a power failure? Piston Ventilators – quiet, hidden – Will you know if the piston fails to move?

New Machines; New Concerns Can a machine have a clinically significant failure after passing an automated checkout? The new machines still do not warn of oxygen consumption from open cylinders if wall pressures drop

New Solutions to Old Problems Raises New Questions!!!