Anaesthetic Equipments By Dr. Mehedi Hasan

Commonly used anaesthetic equipments with their function and brief description are concised here.

1. Anaesthetic Equipments Chairperson Prof. Dr. Munirul Islam Head,Dept. Of Anaesthesiology & Intensive Care; Mymensingh Medical College & Hospital. Presenter Dr. Mehedi Hasan,M.B.B.S. D.A. Resident Mymensingh Medical College & Hospital Session: July 2016-’18 .

2. Instruments used in Anaesthetic Procedure Anaesthetic machine A naesthetic vaporizers A naesthetic breathing system Ventilator Defibrillator Pulse oxymeter Oxygen mask Nasal oxygen set Artificial resuscitator/Bag valve mask Guedel airway Laryngeal mask airway/L.M.A Laryngoscope

3. Instruments used in Anaesthetic Procedure(continued) Endotracheal tube Magill’s forceps Spinal needle/L.P needle Tuohy needle E pidural catheter Tracheostomy tube S uction catheter Central venous catheter Peripheral venous catheter/Intravenous cannula Accessory equipments, e.g Infusion set NG tube Water & sand bag

4. Anaesthetic Machine It is also named as the Boyle’s Machine. The Anaesthetic machine is used by the anaesthesiologists to support the administration of anaesthesia.

5. Anaesthetic Machine(continued) The most common type of anaesthetic machine in use now-a-days in the developed countries is the continuous-flow anaesthetic machine. It is designed to provide an accurate and continuous supply of medical gases with accurate concentration of anaesthetic vapour.

6. Anaesthetic Machine(continued) Parts: Cylinders/ Pipe line gas system Reducing valves Vaporizers Flow meters Sodalime canister Breathing circuits

7. Anaesthetic vaporizer An anaesthetic vaporizer is a device generally attached to an anaesthetic machine which delivers a given concentration of volatile anaesthetic agent.

8. It vaporizes the liquid anaesthetic agent to gas and adds to fresh gas flow before coming out from common gas outlet. Different agent has different vaporizers and color code identifies the type of agent(such as yellow for sevoflurane,purple for isoflurane) Anaesthetic vaporizer(continued)

9. Ventilators A ventilator is a machine designed to move breathable air into & out of the lungs,to provide breathing for a patient who is physically unable to breathe or breathing insufficiently. Primitive mechanical ventilator was “drinker respirator” introduced in 1928,then improvement done by John Haven emerson in 1931. Modern ventilators can act as constant or non-constant generators of either pressure or flow. The ventilator has to execute an inspiratory phase,cycle from inspiration to expiration & an expiratory pause,and then cycle back to inspiration.

10. Ventilators(continued) Pressure generator: It delivers a preset pressure to the patient. Flow generator: It delivers preset flow whatever the resistance & compliance of respiratory system. Power: It is required during inspiratory phase,typically about 20W.Peak power production must exceed peak airway pressure. Cycling: It is initiated by time,volume,pressure,flow or patient triggering. E xpiration: It is generally passive release to the atmosphere.

11. Oxygen Masks An oxygen mask provides a method to transfer breathing oxygen from a storage tank to the lungs. It is of two types. The simple face mask and non-rebreathing face mask. It is made of plastic,silicone or rubber.

12. Nasal oxygen set It is a device used to deliver supplemental oxygen or increased airflow to a patient or person in need of respiratory help. It consists of a lightweight tube and two prongs(which are placed in the nostrils)

13. Artificial Resuscitator Use of artificial resuscitator to ventilate a patient is frequently called “bagging” Also named as- M anual resuscitator Bag-valve mask AMBU(Artificial manual breathing unit)bag S elf-inflating bag

14. Artificial Resuscitator(continued) It is a hand-held device commonly used to provide positive pressure ventilation to those patient who are not breathing or not breathing adequately. The device is a required part of resuscitation kit for trained professional in out-of-hospital settings. It is used within hospital for temporary ventilation of patients.

15. Artificial Resuscitator(continued ) Two principal type of manual resuscitator exists. One version is self filling with air with additional oxygen(but this oxygen is not required for its function) The other version is the flow-inflation type,whice is heavily used in non-emergency application in operating room to ventilate patients during induction & recovery of anaesthesia.

16. Guedel airway It is a medical device whis is an airway adjunct used to maintain or open a patient’s airway.

17. An oropharyngeal airway(OPA) is also known as oral airway.The another type of airway is naso-pharyngeal airway. It does this by preventing tongue falling back on epiglottis, which could prevent the person from breathing When a person becomes unconscious,the muscles in their jaw relax & allow the tongue to obstruct the airway. Guedel airway(Continued)

18. Laryngeal mask airway(L.M.a.) It is a medical device that keeps a patient’s airway open during anaesthesia or unconsciousness. It is a type of supra-glottic airway.

19. L.m.a.(continued) Laryngeal mask was invented by British anaesthesiologist Dr. Archibald Brain in the early 1980’s. A laryngeal mask is composed of an airway tube that connects to an elliptical mask with a cuff which is inserted through the patient’s mouth and once deployed forms an airtight seal on top of the glottis(unlike E.T. T ubes).

20. L.m.a.(continued) It is used by the anaesthesiologists & emergency health-care provider(paramedics) to channel oxygen or anaesthetic gases to lungs during surgery & pre-hospital settings . It is also used as the optional device of Endotracheal tube during failed or difficult intubation,geriatric patients or patients of gross anatomic abnormality.

21. P ulse oxymeter Oxymetry is a spectrophotometric technique that measures % haemoglobin saturation in peripheral blood(Sp ).There are two types of oxymetry,transmissive and reflectance oxymetry.In our OT setting we use tranmissive oxymetry. A pulse oxymeter is a medical device that indirectly monitors the oxygen saturation of a patient. In 1935, German physician Karl Matthes developed the first pulse oxymeter,and finally  

22. P ulse oxymeter(continued) after varying degree of modification it was commercially available in market & had begun to use in operating room from 1983 . A blood-oxygen monitor displays the % of hemoglobin that is loaded with oxygen. Without any pulmonary pathology normal range of % saturation varies from 95-99%.

23. P ulse oxymeter(continued) A typical pulse oxymeter utilizes an electronic microprocessor & a pair of small LEDs facing a photodiodes through a translucent part of the body. One LED is red(wavelength 660nm) and the other is Infra-red(wavelength 940nm).The prototype of Karl Matthes was red & green. Oxygenated Hb absorbs more infrared & allows more red to pass through and vice versa for deoxygenated Hb. The ratio of the red light to the infra-red is then measured by the microprocessors & showed in the monitor.

24. P ulse oxymeter(continued) Advantages : 1. Convenient for non-invasive continuous saturation monitoring. 2. Useful in any setting where patient’s oxygenation is unstable inclusively in ICU,OT,recovery room,post-operative room,emergency etc. Limitations: 1. It cannot be used as a substitute of blood-gas analysis because it gives no indication of base excess/deficit,blood pH or bicarbonate. 2. Pulse oxymeter gives % of bound Hb,so false high reading gives in severe anaemia where blood will carry less total oxygen despite the Hb being 100% saturated.

25. Defibrillator Defibrillation is a common treatment for life threatening cardiac dysrhythmias and ventricular fibrillation. It consists of delivering a therapeutic dose of electric current to the heart with a device called defibrillator. D efibrillators depolarizes a critical mass of the heart muscle,terminates dysrhythmia and allows normal sinus rhythm to be re-established by the body’s natural pacemakers.

26. Defibrillator(continued) T here are different types of defibrillator,e.g. Manual external defibrillator Manual internal defibrillator Automated external defibrillator(AED) Implantable cardioverter defibrillator.

27. Defibrillator(continued) A defibrillator circuit operation consists of two phases,charging & discharging. In charging phase the switch connects the capacitor to the DC power supply,which charges it to deliver the required amount of energy or number of joules set by the operator. On discharge phase the switch connects the capacitor to the patient’s circuit,which enables the stored charge to be delivered to the patient. The inductor in the discharge circuit has the effect of spreading out the delivered pulse of energy to the myocardium.

28. Laryngoscope It is a metalic medical device with in-built light source which is used for direct laryngoscopy.

29. Laryngoscope(continued) This device is of two types,simple laryngoscope & fiber-optic laryngoscope. The blade of the laryngoscope is of two types,curved blade or Macintosh type & straight blade or Miller type.

30. L aryngoscope(continued) Parts of a laryngoscope: Beak/Tip Web/Vertical step Light source Horizontal flange Tongue spatula Hook on base Handle

31. E ndotracheal tubes(e.t. T ube) E ndotracheal tube is a medical device that is nearly always inserted through the mouth or in case through the nose to allow oxygen or anaesthetic gases to the lungs from an external source. Types of endotracheal tube include oral or nasal, cuffed or non-cuffed,preformed tube,reinforced tubes and double lumen endotracheal tubes.

32. E ndotracheal tubes(continued) Parts of an endotracheal tube: Universal airway connector Tube Radio-opaque line Pilot tube Pilot inflator bag Cuff- High volume-low pressure & high pressure-low volume cuff Murphy’s eye Two black lines

33. E ndotracheal tubes(continued) Functions of different parts: Universal airway connector- To connect with breathing circuit or AMBU bag Radio-opaque line- Identify placement of tube radiologically Pilot tube- To inflate the cuff Two black lines- Vocal cords should be in between the lines Murphy’s eye- To keep patency when the secretion blocks the tube & to keep the patency of upper right bronchus.

34. E ndotracheal tubes(continued) Most E.T tubes today are made of PVC . Preformed E.T tubes e.g. RAE(Ring,Adair,Elwyn) tube which is used in Oto-laryngeal surgical procedures. Robertshaw developed double-lumen endo-bronchial tubes for thoracic surgery.This allow single lung ventilation to collapse the another.

35. E ndotracheal tubes(continued) Use of endotracheal tubes: Commonly used for the airway management in the setting of general anaesthesia,critical care,mechanical ventilation & emergency medicine. It can be used also as a route of administration of certain drugs like salbutamol,atropine,ipratropium. It can be used to deliver oxygen in higher concentration than found in air. For human use, tubes range in size from 2.5 to 10.5 in internal diameter.

36. Magill’s forcep It is also known as “Intubating forceps” It is a right handed instrument,angled in two planes which allows for it to be used in the oro & hypopharynx under direct vision during laryngoscopy. It is designed by an Irish Anaesthetist Sir Ivan Whiteside Magill & hence this was named.

37. Magill’s forcep(continued) The most common application of this instrument is to maneuver the endotracheal tube in nasal intubation. It is used to pick up the ET tube in the posterior oropharynx & place its tip into the laryngeal inlet. It can also be useful in clearing foreign bodies from the upper airway in anaesthetized or unconscious patient. Another use of this device is in placing & removing throat packs.

38. S pinal needle The special needle which is used in giving Sub-Arachnoid block(SAB) is known as spinal needle. The very first spinal needle was designed by J. Leonard Corning in 1885.Then the shape of the needle tip started as a cutting bevel & developed into the atraumatic tip in 1891 by Quincke.He used a sharp,bevelled,hollow needle.

39. S pinal needle(continued) There are differnt types of spinal needle tip,e.g . Whitacre: Designed to spread the dural fibers & help reduce the occurance of post-dural puncture headache(PDPH).Yields a distinct “pop” as the pencil point penetrates the dura. Quincke : Short bevelled,cutting tip.Insertion results in the needle cutting parallel to the dural fibers. Sprotte: As the fibers of the dura run parallel to the long axix of the spine,if the bevel of the needle is parallel to them,it will part rather than cut them, and therefore leave a smaller hole.

40. tuohy Needle(Epidural needle) Tuohy needle/Epidural needle is a hollow hypodermic needle which is specially designed to be placed into the epidural space. It is designed with a curved tip to help prevent puncture of the dural membrane.

41. tuohy Needle(continued) Ralph L. Huber, a Seattle dentist was the inventor of this needle. It is known in the name of an American anaesthetist Edward Boyce Tuohy who first popularized it in 1945. Other types of epidural needles include: The Crawford needle The Hustead needle The Weiss needle The Sprotte Spezial needle Wagner needle,Cheng needle,Crawley needle etc are less popular epidural needle.

42. Epidural catheter Epidural catheter is a very thin flexible tube that is implanted into spines & tunneled under skin. It is used as a route of administration of ongoing doses of medication that stop nerves from sensing pain during long term pain management.

43. Tracheostomy Tube Tracheostomy tube is a medical device which is used as a bypass airway after a surgical procedure of making an incision on the anterior aspect of neck named tracheostomy. Tube is sized according to the internal diameter, may be cuffed or uncuffed. Indication of tracheostomy includes severe facial trauma,tumors of the head & neck,acute angioedema and acute inflammatory conditions of head & neck.

44. Tracheostomy Tube(continued) Parts are outer cannula or main shaft,inner cannula & obturator. The obturator is used when inserting the tube to guide the placement of main shaft & is removed when main shaft is in place. There is an inner cannula that may be removed for cleaning or replaced.

45. Suction catheter Suction catheters are flexible,long tubes used to remove respiratory secretions from the airway. The purpose of suctioning is to keep the airway clear of secretions & to prevent plugging. One end is attached to the collecting container which generates suction pressure. Sterilized by ethelene oxide gas.

46. Intravenous cannula An intravenous or I.V cannula is a tube that is inserted into a peripheral vein in order to administration of I.V medication. Its internal diameter is defined by the gauge e.g 20G,22G etc. Another name is peripheral venous catheter.

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