Paediatric Anaesthesia 1996 6: 383–385

Oxygen enrichment of entrained room air duringVenturi jet ventilation of children undergoingbronchoscopy

ANIS BARAKA MD, FRCA

Department of Anesthesiology, American University of Beirut, Beirut, Lebanon

SummaryIntermittent oxygen jet ventilation at an inspiratory:expiratory ratio of1:3 was used to ventilate 15 children undergoing rigid Storzbronchoscopy for removal of inhaled foreign body. Oxygenation of thepatient was continuously monitored by pulse oximetry. In all childrenSpO2 was above 95% when the bronchoscope was above the carina.When the bronchoscope was introduced into one of the bronchi, SpO2

decreased to 70–85% in five children. Delivery of a continuous flow ofoxygen via a T-piece attached to the side-arm of the bronchoscopeincreased the SpO2 >95% in the five children. Oxygen jet ventilationduring bronchoscopy is based on the Venturi principle; the oxygen jetwill entrain room air from the side arm of the bronchoscope whichfunctions as an entrainment orifice. This will decrease the FIO2. TheFIO2 can be increased by flowing oxygen continuously via the T-pieceattached to the side arm of the bronchoscope.

Keywords: bronchoscopy; rigid Venturi; jet ventilation; foreign bodies;tracheobronchial

Introduction bronchoscope. However, Sanders’ technique hasthe disadvantage of lowering the delivered FIO2The inhalation of a foreign body in a child isto approximately 30%. This may be inadequate

a life-threatening accident; early diagnosis andwhenever the bronchoscope is introduced into one

bronchoscopic removal of the foreign body will saveside particularly in patients with decreased lung

the child from serious complications (1–3). A majorcompliance. Thus, the technique may be occasionally

contribution to the anaesthetic management ofassociated with lowering of the oxygen saturation of

patients undergoing bronchoscopy occurred in 1967the patient.

when Sanders introduced the concept of VenturiIn order to increase the FIO2 during intermittent jet

injector for intermittent positive pressure ventilationventilation, the present report describes attempts to

(4). The oxygen jet entrains large volumes of roomoxygen enrich the entrained room air by delivering

air, which enable adequate ventilation, while thea continuous flow of oxygen via a T-piece attached

endoscopist works uninterrupted through the opento the side arm of the bronchoscope. The techniquesucceeded in increasing oxygen saturation in children

Correspondence to: Dr Anis Baraka, Professor & Chairman, undergoing rigid bronchoscopy for removal ofDepartment of Anesthesiology, American University of Beirut, inhaled foreign bodies.Beirut, Lebanon.

383 1996 Arnette Blackwell SA

384 A. BARAKA

All children were premedicated with atropine0.1 mg per year of age. Following intravenouscannulation, anaesthesia was induced with keta-mine 2 mg·kg−1 and suxamethonium 1.5 mg·kg−1.Neuromuscular block was maintained bysuxamethonium drip. Following introduction of theStorz bronchoscope, the children were ventilated byintermittent oxygen jets (20–50 psi) which weredelivered via the Venturi injector at an inspiratorytime 0.5–1 s with an expiratory pause of 2–3 s.Radiometer pulse oximetry was used to monitorcontinuously the oxygen saturation (SpO2). When thebronchoscope was above the carina, the SpO2 wasabove 95% in all children. However, when thebronchoscope was introduced to the bronchus, theSpO2 was decreased down to 70–85% in five of the15 children. The T-piece was attached to the side armof the bronchoscope and oxygen was continuouslydelivered at a flow of 5 l·min−1. The oxygen saturationrapidly increased above 95% in the five children.

Figure 1 Preoperative chest x-ray of these five children showedThe Storz paediatric bronchoscope, with the 16 G Venturi injector pneumonic infiltration or atelectasis complicating theconnected to the proximal end of the bronchoscope, and the T-

inhalation of the foreign body (Table 1).piece with reservoir tubing connected to the side arm of thebronchoscope.

DiscussionMethods

STORZ rigid bronchoscope, equipped with Hopkins’ The Storz rigid bronchoscope, equipped withHopkins fibreoptic optical telescope is widely usedfibreoptic optical telescope was used in all children.

The Venturi injector (16 G) was used to deliver for paediatric rigid bronchoscopy. However, thetelescope occupies a large proportion of the internalintermittent O2 jets, while a T-piece with a reservoir

tubing was attached to the side arm of the lumen of the paediatric bronchoscope, resulting in amarked increase in airflow resistance. Thus, manualbronchoscope, in order to deliver a continuous flow

of oxygen whenever needed (Figure 1). positive-pressure ventilation is impaired, and passiveexhalation is retarded. The use of Sanders’ techniqueThe technique of intermittent jet ventilation was

used in 15 children having an age range between of ventilation which utilizes high pressure oxygenjets can entrain large volumes of room air via thetwo to four years, with a history of choking and

coughing while eating, suggestive of foreign body side arm of the bronchoscope, and hence can providethe necessary pressure and flow required for chestinhalation. The study conforms to ethical standards

as described in the Declaration of Helsinki. inflation. Jet ventilation at an inspiratory:expiratory

Table 1Age, sex, type and site of theinhaled foreign body, as well asthe preoperative chest x-ray

Age (y) Sex Type of foreign body Site Preoperative chest x-ray

2 M Water melon seed Right Obstructive emphysema2.5 M Peanuts Bilateral Pneumonic infiltrations3 F Peanuts Bilateral Pneumonic infiltrations3 M Water melon seed Right Atelectasis3.5 F Peanuts Right Atelectasis

1996 Arnette Blackwell SA, Paediatric Anaesthesia, 6, 383–385

JET VENTILATION DURING BRONCHOSCOPY 385

ratio about 1:3 allows adequate exhalation time which during jet ventilation, by delivering a continuousminimizes air trapping. flow of oxygen via a T-piece system connected to the

The Sanders’ ventilation technique is based on side arm of the bronchoscope which functions asthe Venturi principle: passing a high pressure gas an entrainment orifice. The technique can improvethrough a narrow orifice creates a marked decrease oxygenation in children undergoing bronchoscopy.in the pressure surrounding the injector; this decreasein pressure entrains room air and markedly increasesthe total flow. However, the technique by entraining Referencesroom air decreases the FIO2, and hence hypoxaemia

1 Slim M, Yacoubian H. Complications of foreign bodies in themay result when the bronchoscope is introduced into tracheobronchial tree. Arch Surg 1966; 92: 388–393.one of the bronchi, particularly when the foreign 2 Harboyan G, Nassif R. Tracheobronchial foreign bodies: a review

of 14 years’ experience. J Laryngol & Otol 1970; 84: 403–412.body inhalation is complicated by chest complication3 Baraka A. Bronchoscopic removal of inhaled foreign bodies insuch as atelectasis or pneumonia.

children. Br J Anaesth 1974; 46: 124–126.The present report describes a simple technique 4 Sanders RD. Two ventilatory attachments for bronchoscope.

Delaware Med J 1967; 39: 170–175.for oxygen enrichment of the entrained room air

1996 Arnette Blackwell SA, Paediatric Anaesthesia, 6, 383–385