Resident's Corner

Anesthesia Math & Physics
& Vapors
Anesthesia Machine Checkout
Malampati Classification
Hemodynamic Parameters

Local Anesthetics: Maximum Doses
APMS Pager Responsibilities

Reprint Library (Articles & Lectures)

CA2 Resident Pain Rotation NEW

To submit information for these pages, see Tom VerLee (

Anesthesia Math & Physics
Courtesy J. Kent Garman MD, 
Stanford U. 11/2000

1% = 10 mg/ml

1:100,000 = 10 mcg/ml

1.36 mmHg = 10 cm H2O

1 atm = 760 torr = 14.7 psi (at sea level)

1 M = 22.4 L gas

time constant = capacity/flow

compliance = volume/pressure

tension = Pressure/wall thickness

Tank facts: Medical Gases

@760mmHg, 700 Fahrenheit

Cyl Size PSI Liters
Oxygen E
4¼ x 26"
2015 704
9¼ x 51"
2492 7986
N2O E 745 1590
H 745 16057


Agent MAC B/G VP Metab
MOF 0.16 12.0 22.5 50
ISO 1.15 1.4 240 0.2
ENF 1.68 1.9 172 2-5
HAL 0.75 2.4 244 15-20
DES 7.25 0.42 669 <0.1
SEV 2.05 0.68 160 2
N2O 107 0.46 0.46 .0004

MAC =Minimum alveolar concentration at one atmosphere at which 50% of patients do not move in response to a surgical skin incision.

B/G =Blood:gas partition coefficient is inversely related to the rate of induction.

VP =Vapor pressure is reported as mmHg at 20 Deg C.

Metab =Percentage of absorbed anesthetic undergoing metabolism.


Copper Kettle/ Vernitrol (for when you go to Haiti):

1% = x(gas) + 100(cc O2) / 100x(FGF) where x=50 for iso/halo

x=33 for sevo/enf, x=90 for desflurane

FGF = total fresh gas flow

Basic Preoperative
Anesthesia Machine Check List:

Approved by Q/A Committee July 2001

These checks shall be completed before an anesthesia machine is used at the beginning of each day and after mechanical adjustment or cleaning of the machine.  Item 3a should further be checked before each use of the machine or after the soda lime canister has been manipulated.

Turn On & Inspect
Gas Evacuation System
Breathing Circuit
Ventilator Circuit
PopOff Valve
Emergency Cylinders
Oxygen Analyzer
Clinical Engineering Phone #

1. Turn oninspect the machine and rubber goods for damage and for missing parts.  Special attention should be paid to the following:

  a. Soda lime absorber and soda lime (check for color of soda lime, replace if necessary)
  b. Proper attachment of all hoses and tubing

2. Gas Evacuation System:

  a. Be sure system is properly attached to machine and exhaust vent.
  b. DO NOT tape connections.

3. Breathing Circuit

  a. Connect a single length of patient circuit tubing to the inhalation and exhalation ports with the reservoir bag in place.  Pressurize the circuit, using the oxygen flush valve, to 30 mmHg.  If the circuit does not maintain the pressure at 30 mmHg, the volume of the leak is the flow of oxygen necessary to maintain a constant pressure.
  b. Compress the reservoir bag manually to a sustained pressure > 50mmHg and confirm integrity of the circuit and high pressure alarm function.

4. Ventilator Circuit

  a. With the breathing circuit connected and a reservoir bag on the patient end of the circuit, turn the ventilator on to a  pre-set TV and rate to insure proper function of the ventilator.
  b. After completing (4a) above, remove the reservoir bag from the patient end of the circuit, place your thumb over the end and assure the ventilator will develop a pressure of 50mmHg.
  c. Remove your thumb from the circuit and allow ventilator to cycle to confirm low pressure alarms.

5. Pop-Off Valve
  a. The pop-off valve should open at 3 mmHg pressure in its wide open position.

6. Vaporizers
  a. Check to be sure that only one vaporizer can be turned on at any time.
  b. Be sure vaporizers are filled and turned off.

7. Emergencv Gas Supply
  a. Check oxygen "E" cylinders attached to machine to be certain that each cylinder contains more than 500 psi.  If less than 500 psi, change the cylinder.  (A full "E" cylinder should read 2200 psi.)
  b. Check nitrous oxide "E" cylinder attached to machine.  If the nitrous oxide "E" cylinder pressure is less than 700 psi, the tank should be changed immediately.  A spare full "E" cylinder of nitrous oxide should be available if the "E" cylinder is to be the primary source of nitrous oxide.

8. Oxygen Sensor/Analyzer
  Calibrate the oxygen sensor/analyzer per manufacturers recommendations.

9.Clinical Engineering Phone #

-Maine Medical Center: x4756
    Mike Hodge, Jim Sanuk

-Brighton Campus: x4893
    Dennis Wildes

A Complete Checklist Card is attached to every machine for additional information

Local Anesthetics-
Max single dosages in adults

Courtesy J. Kent Garman MD, 
Stanford U.

Amides: (mg/kg)




























Esters: (mg/kg)
















On-Call APMS Responsibilities for  Anesthesiology Residents

James Pisini, D.O.

Policies and procedures and your responsibilities when covering the APMS pager. 

1. The most senior resident on-call should carry the APMS pager whenever possible.

2. ALL residents must call the attending anesthesiologist for any change in:

Physical condition
Respiratory status
Mental status
Neurological status
Hemodynamic status
Treatment plan

3. All patients MUST be seen and a note written in the chart documenting any changes in clinical condition and/or treatment plan. 

4. All first year residents, if carrying the APMS pager, MUST call the attending anesthesiologist for ALL pain calls at night.

5. IV PCA continuous infusions CANNOT be ordered by anesthesiology residents without prior discussion with the attending staff.

6. ALL calls regarding pediatric pain patients must be 
reported and discussed with the attending staff. 
No treatment changes are to be made prior to 
discussion with the attending.

7. ALL calls regarding intrathecal catheters and complex chronic pain patients must be reported and discussed with the attending staff. No treatment changes are to be made prior to discussion with the attending.

8. If a critical event occurs, please follow the critical event algorithm (attached) to assist in our review of the event for QA purposes.

Thank you for your attention and assistance in providing safe and optimal pain treatment for our patients.


    (Connected? Also available in PDF format by clicking HERE)

The APMS has developed an algorithm to follow when critical events occur in APMS patients. This is intended to assure that information is collected which will assist our thorough evaluation of an event. This document is not intended to address the clinical management of the patient, but to define the process for data collection after an event has occurred.


1) Review infusion pump / PCA settings ASAP. Check the drug(s), concentration(s), pump(s) settings. Check the current physician order for the drug. Do these match? Has there been an error in the administration of the drug, or an error in physician order entry? 

2) If the patient is receiving PCEA/PCIA or PCA medications, check the dosing history. Obtain the amount delivered over the last hour, and over the last 24 hours.

Note: it is imperative to ascertain the information above (#1 &2) promptly. 
If the pump is removed from the patient and returned to CSD or the drug vial is removed from the PCA pump, this information will be lost.

3) Send infusion bag or PCA syringe to the pharmacy / lab to determine the volume remaining (does it coincide with the expected volume based on dosing/infusion parameters). Send the bag to the lab to have the solution content analyzed. These can be accomplished by speaking directly to the pharmacist (ext #2151). Ask for Sue Fraser, Rph if available.

4) Order toxicology screen. Order "Toxicology Panel- Substances of Abuse" 

5) Speak directly with the nurse caring for the patient to obtain first hand information about the event before the details are forgotten.

6) Print out the seven-day medication list to ascertain what drugs have been given. Have additional opioids or CNS depressants been given? This can be obtained in MIS by selecting "Master", then "reports", then "7 day med summary".

7) Review the medical record.

This Memo and a FORM for Reporting a Critical Event is also available in PDF format by clicking HERE (assuming you're connected to the internet)