PROBLEMS & ANAESTHETIC M/G FOR BRANCHOSCOPY AND LARYNGOSCOPY :

1. Introduction.
2. Pre op preparation and premedication.
3. Indications
4. Specific problem antteq.
5. Regional block & topical anaesthesia
6. Inhalational anaesthesia
7. IV anaesthesia
8. Techniques for ventilation during the procedure.
9. Complications.

INTRODUCTION :

In recent years endoscopy techniques have rendered more and more regions of the body accessible to direct visualisation. At the same time improvements in the apparatus design have made the procedure relatively less hazardous and more informative. Branchoscopy and laryngoscopy are most common invasive investigations.

The choice of anaesthesia for laryngoscopy, fibre optic branchoscopy, rigid branchoscopy involves surgical anaesthetic and pt. Factors that enter into selection of suitable technique.

The pts pathological lesion and its pathophysiological impact on the airway during anaesthesia are the ultimate elements to be considered.

General anaesthesia for thoracic diagnoestic procedure can be very challenging. Not only does the airway have to be shared with the surgeon but after the same instrument e.g. a ventilating branchoscope, prior communication with the surgeon concerning the pts status and the proposed surgical plan is essential. Close co-operation and communcation which are vital intra operatively are initiated by the pre operative contact.

The selection of regional block and topical anaesthesia is an equal challenge proper pt. Selection skill at performing the block and choice of correct doses and drugs are the demand placed on the anaesthesiologist.

The objective of general anaesthesia includes analgosia, unconsciousness, skelectial muscal relatation and control of excessive sympathetic or pooasympathetic activity to noxious stimule. However only analogeia sedation and control of excessive reflex activity are required during local or regional block procedure.

PREOP PREPARATION & PREANAESTHETIC MEDICATION :

As in all surgery it is important to evaluate the physical condition of each pt. And to achieve the healthiest possible state before surgery, this being an important determinant of peri and post operative morbidity and mortability.

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2. PROP. ASSESSMENT :

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2. DIABETIS : Diabetes should be properly controlled before surgery. Oral hypogoycemic agent insulin is armited on the morning of the operation. A blood glucose estimation is performs and a 5% dextrose infusion with an appropriate amount of soluble insulin added to the solution is administered at a rate of (1.5 ml. /kg. Per hr) The blood glucose level should be checked immediately after an operation or intra op during long procedures and maintained at around 10 mm.
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4. CONCURRENT DRUG THERAPY : Adrenangic blocking drugs should be contained upto the time of operation.
5. Narrotics particularly pethidive can produce dangerous side effects such as excessive resp. depression, hypo or hyper tension, sureating, narrsea, collapse. Pt. On prolonged storied therapy may need stored cover during operation and in immediate post – op. Cover.

   Pt. One contra ceptive pills should stop taking these tablets for atleast one complete month before surgery, but for emergency operations, prophylaxus with subent. Heparin or dexoran infusion should be considered to reduce the risk of postop. Venous thrombosis.

6. Pregnancy in the first or last trimester is usually considered a C/o o elective surgery. These may be risk of miscarrying in early staes and in final meeks, increased intra-abdonimal pressure may lead to respiratory embarrasment and used risk of gastric regurgitation.

PROP INVESTIGATIONS :

Routine investigations include haematological and electrolyte screening and bl. Gr. And cross match, if significant blood loss is anticipated.If anaenisa is present cause should be sought and beated. If pt. Has sickle cell ds. Then is high risk of haemolyses and multiple inflection as the abnormal Hbs forms crystals when O2 tension is reduced. Directives taken over long periods may lead to hypokalemia (< 3 mmol/L). It should be treated before energy.

Urine examination, reval function test should be done Pt.with H/o CVS O/s should have an ECG and chest X-ray for myocardial ischaemia, incipient failure and cardiac enlargement.

Pt with compromised airway should have a PA & lat. View neck X-ray and personally reviewed by anaesthetist.

Presence of stridor in a resting state suggests significiant airway obstruction. In such cases indirect laryingoscopy should be done. Sellers divides pt. Into 3 groups in classification of peri operative airway obstruction.

GROUP I : Who structed airway at rest a small lesion.

GROUP II : Would degree of respiratory obstruction at rest or a large lesion.

GROUPIII : Gross airway obstruction at rest.

PRE OPERATIVE MEDICATION :

It includes sedatives, anti cholinergic, prophylactic, antibictics, prophylactic, anticoagulants.

A careful and reassuring explanation w.r.t. the operation itself, induction of anaesthesia and immediate past period will be more helpful to apprehensive pts.

If pt. Is very anxious sedation in the form of 25 mg. Riazeperm is given.Aim of sedation is a good night’s sleep before surgery.

Atropirve given pre operatively will take care ofsecretions as well as brodyeardia during laryngoscopy and application of topical anaerthesia to the caryma. It atropine is more effective for production of dry month and throad. Pt. Given atropine injection or aerosol demonstrate significant bronchordilator effects that help to overcome some of the deleterious effects that help to overcome some of the deleterious effect of filroptive branchoscope on pulm function.

Pt. C congenital heart ds or value ds. Who run risk of bactereria during surgery require antibietia cover before and during surgery.

Pt. At risk of various thrombesive should be considered for prophylactive subent heparin 5000 units given before operation and 5000 units at 12 hrly intervals until the pt. Is fully ambulant. Unfortunately, this T/t will TSC bleeding during operation and also the risk of post op.

Indications for branchoscopy

Diagnostic

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2. Cough
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4. Haemophysis
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6. Wheeze
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8. Atelectasis

Unresolved phenimonia

Diffuse lung ds.

Pre op evaluation

Rule out metastasis

Abnormal chest X-ray findings

Recurrent laryngeal N paralysis

Diaphragm paralysis

Acute inhalation analysis

Exclude frachco oesophageal fistula

During mechanical ventilation

Selective brouchography.

Therapentic

Foreign bodies

Accumulated secretions.

Atelectesis

Aspiration

Luing abscess

Reposition endctracheal tubes

Placement of endobronchial tubes

Indirections of laryngoscopy

They are

Astoc and their apentic

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2. Endotractual intubation
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4. Ca. Larynx
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6. Laryngeal papilloma and nodules.
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8. Change in voice.
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10. Upper respiratory obstruction.

Fibroptic Laryngoscopy

In difficult intubation

e.g. laryngeal deviation.

SPECIAL PROBLEMS FOR BRONCHOSCOPY :

Rigid brouchoscopy is a short procedure, often lasting less than five minutes and rarely continuing for more than fifteen.Rigid brouchoscopy is uncomfortable for a conscious subject but can be carried out under local anaesthesia by a skill operator. Surgical opinion favours the rigid brouchoscope for theimmediate pre op location of tumours and assessment of carinal or brouchial rigidity, it is also the instrument of choise for therapentic mancovers such as extraction of foreign body, dilatation of strichures or insertion of radio active gold grains.

External diameter of adult rigid brouchoscope is 11 mm. Various sizes of Negns brouchoscope are available for paediatric use.

The fabro optic brouchoscope is 4-6mm. In external diameter,is easily introduced under local anaesthesia and can penetrate to the second or third generation of sub-segmental brouchi. Small brouchial bio[soes pr brushing can be taken through the section channel and this is also used for tracheo brouchial biopsies or brushing can be taken through the suction channel and this is also used for tracheobrouchial biopsy of the lung, regional studies of pulm function and broucho alvcolor lavage to harvest alnucolar macrophase.

These are specific problems if rigid brouchoscopy is carried out under general anaesthesia by our in experienced person. They are :

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2. These is competition between brouchoscopist and anaesthetist for control of the airway.
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4. Instrumentation of the respiratory treat is a potent cause of brouchospasm, laryngospasm and cardiac dysrhythmias.
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6. The procedure is sometimes indicated as an emergency on an imprepared poorly assessed patient who already has imparred CVS or respiratory function.
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8. Ventilation can be compromised even function during and after the procedure it, for example a cobar brouchers is obstructed by bronchoscope, if spason is prevoked, or if huge is caused by a biopsy.

Conditions in with rigid brouchoscopy is inchride gross deformity of the month or neck, severe acute hypoxia, respiratory obstruction, massive broucho pleural fistula and superior venacaval obstruction.

Anaesthetic technique chosen must provide analgesia, sufficient relaxation to allow easy passage of the rigid instrument, abolution of reflexes from the respiratory tract and the maintenance of adequate gas exchange. Prompt recovery of consciousness, respiratory drive and the cough reflex are desirable if general anaesthesia is used. Topical analgesia, deep inhalational anaesthesia or light anaesthesia with an IV agent and muscle relaxant all fulfill at least somne of these requirements.

Spontaneous respiration is preferred in those cases where there is a foreign body, where these are copions brouclinal secretions, where a brouchopleural cyst or fistula is present or if there is upper airway obstruction.

Hypoxaimia develops during fibre optic branchoscopy with an average dective of PaO2 by 20 mm Hg and lask for 1 to 4 hrs. following the procedure. This is treated by raising the PIO2 by O2 supplementation. Some pts.may develop used airway obstr. After fibre optic brouchoscopy probably sec. To direct mechanical activate of cough and irritative reflexes in the airway and possibly muscosal oedema airway and pssibly musosal oedoma.

The fibre optic is passed thrrough nose under LA.Premed with a vagotytic and light sedation is customary. The larynx, trachea and brouchi are anaesthetized under direct vision by injecting hgnocane thro. The brouchoscope as it is advanced.If general anaesthesia is indirected then fibre optic brouchscope can be passed thru. An 8 or 9 mm. Endotrachcal tube and ventitation cond. Without difficulty. The arnulus between the brouchoscope and endotractial tube should be atleast 2mm. To allow the free passage of gas in and out of the lungs as well as easy movement of the brouchoscope within the tube alternative method of ventilation is necessary for children and adult or if the endoscopist wishes to examination the laryux or walls of brachea.

During laryngoscopy the surgeaon required a clear view, unmobile cords and adequate space for inspection and instrumentation and good anaesthetic practice demands overall safety and adequate resp. exchange, protection of lower airways and schable and speedy recovery of reflexes at the end of procedure.

Fibre optic laryngoscopy is chiefly usefulin adults where of the anatonical difficulties or intolerance of the mirror, indirect laryngoscopy proves impossible. The method is simple and quick and can be done cont detention of the pt. With the help of adequate topical anaesthesia. The laryngial interior is scarred minutaly at all slgs, biopsy forceps will yield a useful speciman of a lesion and photograph can be taken if permanent secord is needed.

REGIONAL BLOCK & TOPICAL ANAESTHESIA FOR LARYNGOSCOPY OR BRONCHOSCOPY :

Topical analygesia can be used for direct laryngoscopy, tracheal intubationin awake p/.s for fibre scopic or rigid brouchoscoy in point with a compromised airway in whom GA may ppt complete respiratory obstruction.

Topical anaesthesiua of the orophasyux is obtained by giving the pt. 5-10ml. Of 2% xylocaine viscone and instructing him to spread it around his month and retain it on the back of his tongue. After a few month remaining fluid should speat out. Any remaining pharyngeal reflexes can be obtained by spraying the soft palate and oropharyna with 4% hynocaive. A swab soaked in 4% hynocaine is unsorted with a laryngeal forceps in turn into each pyriform fossa by sliding of over the back of the tongue. Swab is held there for about 1 min. to block the internal laryngeal nerve. Anaesthesia of the brachea can be obtained by spraying hgnocaine thro the cords under direct vision or through cricathyroid membrance.

Ultrasonic nubulization of hydrocarine with the pt. Breathing spontaneously is popular for fibre optive brouchoscopy and can be used for laryngoscopy as well.Thus method delivers topical anaesthesia to all brouchial tree that the fibre optic brouchoscope reaches.

Percentaneous transcried puncture provides topical anesthesia to the upper and lower resp. tract. The technique is C/l in a point with an enlarged thyroid, Ca or B of the tracheobronchial tree, a bleeding anathesis or obscured landmarks. Skin is unfiltrated with LA via a 25G needle and the number punctured with 22G eathetor and needle, aspiration of pourth confirms position. Syringe is firmly attached to cathetor and xylocane is injected as the point forcefully inspires. If large needles are used bleeding ma occur.

Other complications include needle breakage, vessel laceration, local haematoma, local infection and abscus ands.c. emphysema.

Sperfic nerve block for laryngoscopy :

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2. Superior laryngcal nerve block. It is a brach of vagus divides into external mortor br. To cricothyroid muscle and an internal sensory br with supplies mucosa of larynx, the laryngeal surface of epiglottis and part of post larynx.

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2. GLOSSOPHARIGNGEAL FLEXURE BLOCK :

INHALATIONAL ANAESTHESIA

Point is highly premedicated, may be only with IM atropine, Halothane or ether are most commonly used agents. The depth of halothane anaesthesia changes rapidly so that a point anaesthetized to the point of resp. arrest can tighten to an unacceptable degree during all but the shortes procedure. Brouchoscopy and the administ of more anaesthetic have to alternate and the brouchoscopist is at risk of redation from exhaled halothane.

With other risk of explosion is there unless the brouchoscope is illuminated from a cold light source induction as slower, stormier but conditions during the brochoscopy are more stable.

INTAVENOUS ANAESTHESIA

This is the usual choice for brouchoscopy under general anaesthesia and is based on light narcosis and total paralysis with gas exchange.

Prevned include alropine and benzodrazepine as air anxiolytsic and annestic agent. If tachrycardia is to be avoided glycopyrrolate may be used as vagolytic.

Induction is usually with thiopentrid suxarnethonium is given after induction, the lungs inflated with O2 and then the vocal cords and trachea are sprayed with lignocarine. Lungs are again inflated with O2 for a few breaths just before insertion of scope.

Increments of inducing agent and suxamethonium are used for maintenance.

Intra operatively points colour, movement of the chest and abdomen, peripheral pulse, BP are monitored.

Post op, point is turned on his side with deceased side down nurvards to avoid soiling the contralateral lung with blood or secretions. O2 is administered thro’ face mask and point is observed till return of protective reflexes.

BRONCHOSCOPY

Techniques of ventilation for ventilation is controlled by one of four techniques with includes.

1. Apnocic oxygenation.
2. A ventilating brouchoscope
3. Jet ventilating involving
4. Venturi principle.
5. High frequency positive pressure ventilation.

It is carier to maintain arterial oxygenation then to eliminate Co2. The techniques described differ both in this respect and in their requirements for additional equipment.

1. APNOCIC OXYGENATION :
2. It is the simplest method. It involves pre oxygenation to eliminate N2 from the alneolar gas, followed by the insertion of a catheter, so that tip lies just above carina O2 is insufflated thro it, at 6 Ltrs /min. through brouchoscopy but no attempt is made to achieve any vital exchange of gas satisfactory arterial oxygenation is maintained but there is progressive rise in arterial CO2 tension 3 mm. Hg/min. This technique is unsuitable if brouchoscopy is likely to be psolonged.,
3. VENTILATING BROUCHOSCOPE :
4. It can be constructed by fixing side arm for gas exchange to a conventional rigid brouchoscope and sealing the proxural end with a glass window. Satisfactory Ventilation is rarelypossible because brouchoscope is a poor fet within the trachea. A similar system can be devised by pushing a short large bore endotracheal tube into the end of a conventional brouchoscope.
5. JET PRINCIPLE :
6. The injector principle was first described by Sanders in 1967 and the safety it imparts, even under such difficult circumstances as the removed of a foreign body from brouchial tree of a small child has made it popular. O2 from high pressure source is injected inter muttently through a narrow needle placed at the proxtural end of brouchoscope.The venturi effect with this creats entrain atur air so that lungs can be inflated with O2 enriched air. Expirationoccurs passively through and around the brouchoscope. The system consists of a high pressure source of O2 (60 PSI) an ON/OFF tap, high pressure connecting tubing and a needle of suitable size. The extent of air entrainment and the pressure created can be altered if the driving gas pressure is adjusted with a reducing valve attached to an O2 cylinder.

   PASTE DIAGRAM

   Entertainment effect of venturi jet. Gas under high pressure in tube A expands at B producing a suction effect at C.

   Disadvantage : Of this method are that blood and particulate matter may be blown down the trachco brouchial tree and anaesthesia can not easily be maintained with inhalational agents.

7. HIGH FREQUENCY : Positive pressure ventilation HFPPV at rates between 60 and 100 /min. has been developed to provide adequate atveolar. Ventilation at a low airway pressure. Advantage is that there is no entrainment of air and so anaesthetic gases can be delivered at known conc.

1. 1.  
   2. Using a tracheal tube : A small naral or oral cuffed tracheal tube secures airway provide protection from sciling and allows adequate ventilation airway resistance is high so controlled ventilation using muscle relaxants is essential.
   3. Disadvantages are that it interferes with good surgical access and tubes can become occluded.
   4. Using a catheter : A small catheter is positioned with the tip midway between the cords and carina. Once anaesthesia is deepered larynx and trachea are sprayed with 4% lignocaive catheler is introduced and O2 and anaesthetic agents are insufflated through it with the point breathing spontaneously. It gives better surgical access but disadvantage are the lack of protection of lower airway and with slight movement of cords surgeon is subjected to exhaled anaesthetic gasses.
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   6. Using jet ventilation : Advantage is an unobstructed view of larynx. The technique is already described. During laryigo scopy cords must be fully relaxed and the lesion must not cause mechanical obstr, to airflow otherwise dangerously high intra tracheal pressure may be generated with resultant barstrum.
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   8. High frequency ventilator : It is a recent method of jet ventilation, ventilation at about 100 breaths /min. with small lidal not provide good gas exchange. A stiff catheter 4.0 min. in diameter is used to minimise vibrations due to rapidly alternating pressure.

COMPLICATIONS

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2. Interference with respective caused by obstr. Or drug induced depression of central drive or muscle tone. The task is often greatest after the examination and it safer to pass an evdotracheal tube and continue positive. Pressure ventilation till adequate spontaneous respective is required.
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4. Haemorrhage : Can be caused by biopsy of a friable tummour or due injury to major vessel. If bleeding continues at the end of procedure it is safer to leave brouchoscope in place so that suction can be continued until the point is awake and has adequate reflexes.
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6. Dysrhythmras : Can be provoked by hypoxia, hypercarbia, instrumentation of the larynx and trachea or by incremental doses of suxanethonium Bradycardia related to incremental doses of suxamethonium should be treated with IV atropine. Other dysarhythmras responed to improved reviulation deepening the level of anaesthesia of movement of the bronchoscope.
7. Manipulation in and around the larynx may cause a rise in blood pressure, tachycondra dysrohythminas, myocardial wihaema and even cardiac assest. Use of topical anaesthesia will prevent tachjeodia and hypertensive response to laryngoscopy. The procedure must be carried out slowly to avoid triggering the reflex.

   Tachycardia decrease the time available for coronary perfusion and hypertension increase the work load of the heart. Sometimes B adrenergic blocking drugs are used for disschythnvious.

8. Damage to the lungs or airway : It will occur if high pressure is allowed to build up beyond the tip of brouchoscope. This can occur if gas cannot escape through brouchoscope or around it, injector is a potent cause of excessive pressure leading to barotrauma.
9. Pneumomediastimum, surgical emphysema, lung supture, pneumothorax and air embolism can result.
10. Displacement of cather : If eathetor of jet reventilation is displaced out of the trachea, large volumes of gas can be jetted into GIT. There will be used risk of gastric regurgitation. If it is suspected that gas has entered the stomach a gastric tube should be passed and kept in place till point is awake.
11. If the catheter tip goes beyond the carina one lung anaesthesia will result and dangerously high intrabrouchiral pressures may be generated.
12. Awareness during brouchoscopy under GA is disturbingly. Common when the modern technique of light IV anaesthesia and muscle relaxation is used. It includes accounts of instrumentation, paralysis conversation (?) or chest pain. Premedication with specific anxiolytic or amnerise drugs will help to prevent recall.
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14. Drug toxicity : When we are using local anaesthesia drug toxicity is observed.

1.  
2. Kaplan

4. Rothard & Blackweight