Publisher's copy made available with the permission of the publisher© 1999 Australian Society of AnaesthetistsTwo cases are presented which illustrate the disastrous consequences possible when an anaesthetic breathing circuit is obstructed by a foreign body. Despite reports of previous similar cases, work practices and equipment manufacture or design continue to allow for such events to occur. The importance of both pre-anaesthetic testing of the entire circuit including attachments such as the tracheal tube connector and filters, and the removal of these parts should obstruction occur, is emphasised. Use of “clear” transparent breathing circuit components and opaque or brightly coloured packaging and caps which could potentially cause obstruction should decrease the incidence and facilitate the diagnosis of this problem.M.J. Foreman, D. G. Moye

Foreman, M. J.

Moyes, Donald George

Anaesthesia and Intensive Care

English

Adelaide Research &amp; Scholarship

Anaesthesia and Intensive Care, Vol. 27, No. 1, February 1999Anaesth Intensive Care 1999; 27: 73-75Anaesthetic Breathing Circuit Obstruction Due to Blockageof Tracheal Tube Connector by a Foreign Body—Two CasesM.  J. FOREMAN*, D. G. MOYES†Department of Anaesthesia, The Queen Elizabeth Hospital, Adelaide, South AustraliaSUMMARYTwo cases are presented which illustrate the disastrous consequences possible when an anaesthetic breathing circuitis obstructed by a foreign body. Despite reports of previous similar cases, work practices and equipment manufactureor design continue to allow for such events to occur. The importance of both pre-anaesthetic testing of the entirecircuit including attachments such as the tracheal tube connector and filters, and the removal of these parts shouldobstruction occur, is emphasised. Use of “clear” transparent breathing circuit components and opaque or brightlycoloured packaging and caps which could potentially cause obstruction should decrease the incidence and facilitatethe diagnosis of this problem.Key Words: TECHNIQUES; EQUIPMENT: breathing circuit, tracheal tube; COMPLICATIONS: obstruction, foreignbody, tracheal tube connector, crisis managementCASE IA 35-year-old male was brought to the AccidentUnit following a high-speed motor vehicle accident.On arrival, he had bilateral fractures of ribs 3 to 6with presumed pulmonary contusion and a bloodalcohol of 0.20 gm/dl. Over the next six hours, heremained relatively stable haemodynamically but wasnoted to have a falling haemoglobin oxygen satura-tion (SaO2) which required supplemental inspiredoxygen to maintain an SaO2 of 95%. Due to increas-ing abdominal pain, an abdominal proof puncturewas performed. This was positive for blood and hewas scheduled for laparotomy. After several minutespreoxygenation, a rapid sequence induction was per-formed and he was easily intubated. There was com-plete obstruction to ventilation. The tracheal tubewas removed and a second tracheal tube inserted withno improvement. A suction catheter was passed without significant resistance through the swivel con-nector down the tracheal tube. The patient’s  SaO2rapidly decreased. Bilateral chest needles were in-serted to exclude pneumothoraces. The tracheal tubewas removed and mask ventilation instituted.Hypoxic cardiac arrest ensued and the patient couldnot be resuscitated. Post mortem demonstratedpulmonary contusion and  a mesenteric tear.Examination of the tracheal tube connector revealedan intravenous giving set cover had lodged in thefresh gas inlet of the Portex Blue Line swivel connec-tor, totally blocking inflow of fresh gas (Figure 1).CASE IIAn 82-year-old female with a fractured neck offemur was scheduled for a right Compression HipScrew under general anaesthesia. Her past medicalhistory included severe dementia, mild chronic airways obstruction, hyperthyroidism and atrialfibrillation.After preoxygenation for three minutes, a rapidsequence induction was performed with thiopentoneand suxamethonium, and the patient was easily*M.B.B.S., F.A.C.R.R.M.,Anaesthetic Registrar.†F.R.C.A., F.A.N.Z.C.A., Professor of Anaesthesia.Address for Reprints: Dr M. J. Foreman, PO Box 841, Kent Town, S.A.5071.Accepted for publication on November 9, 1998.FIGURE 1: Showing Portex Blue Line swivel connector in the lefthand and intravenous giving set cover held in the direction inwhich it lodged. intubated with a size 7.5 Portex tracheal tube.Ventilation was almost completely obstructed and theSpO2 fell to 90%. Auscultation of the chest revealedextremely poor air entry despite the use of highmanual infla-tion pressures. Repeat laryngoscopy, re-intubation, changing anaesthetic machines, and pass-ing a suction catheter beyond the end of the trachealtube all failed to correct the obstruction. It wasdecided to abandon the surgical procedure and trans-fer the patient to the Intensive Therapy Unit forfurther investigation and management. Duringpreparation for transport, a Mapleson Class B circuitwas connected directly to the tracheal tube, withimmediate relief of the obstruction. The anaesthesiaand surgery proceeded and the patient made anuneventful recovery. In this case a concerted effort was made to elimi-nate the circuit as the cause of obstruction to ventila-tion. Despite this, when the patient was transferredfrom the induction room to theatre to access anotheranaesthetic machine, the tracheal tube connector,which had remained on the patient’s bed, was incor-porated into the new circuit on the second anaes-thetic machine. Examination of the anaestheticbreathing circuit revealed that the black flexibletracheal tube connector (“Liquorice Stick”) wasnearly totally obstructed by a BRAUN luer lock injec-tion site (“yellow bung”) for intravenous cannulas(Figures 2a and 2b).DISCUSSIONThese cases illustrate the potential difficulty indiagnosis and the possible disastrous consequenceswhen an anaesthetic breathing circuit is obstructed bya foreign object. A literature search (Ovid Medline)revealed numerous reports of similar incidents (refs1-8). Despite these reports there continues to exist asituation where both work practices and equipmentmanufacture or design allow for anaesthetic breath-ing circuit obstruction due to foreign body.The authors recommend the following to minimisethe incidence of such events and the likelihood of anadverse outcome should such an obstruction occur.1. Transparency of CircuitryA significant number of the reported obstructionsto anaesthetic breathing circuits occurred in equip-ment which was opaque. The entire anaestheticbreathing circuit should be composed of “clear”transparent material. Packaging material of anaes-thetic equipment and items such as caps for intra-venous ports and gas sampling sites should be com-posed of brightly coloured material so that they canbe easily identified if accidentally incorporated intothe circuit.2.  Eliminate the “Whole” CircuitIn the case of unexpected obstruction to ventilationduring anaesthesia it is recognised that the elimina-tion of the anaesthetic breathing circuit as the causeof obstruction is an immediate priority (refs  9-10).The Crisis Management Algorithm of W. B.Runciman et al (ref. 10) outlines the steps involved inthe process of eliminating the whole circuit. The firststep involves systematically checking the trachealtube (or other airway in use) including removing andreplacing if required. The second step is eliminationof the anaesthetic machine and ventilating with a self-inflating (e.g. Air Viva) bag.The rationale behind first eliminating the circuitwhen clinicians are faced with a case of obstruction toventilation is simple. The obstruction will either bedue to equipment or patient factors, therefore therapid elimination of equipment as the source ofobstruction will not only relieve the obstruction toventilation in a significant number of cases but willalso markedly reduce the diagnostic dilemma facedby the clinician.It is unfortunate that in both these cases the cause74 M. J. FOREMAN, D. G. MOYESAnaesthesia and Intensive Care, Vol. 27, No. 1, February 1999FIGURE 2a: Braun luer lock injection site tightly wedged in blackendotracheal tube connector.FIGURE 2b: Showing luer lock injection site bung and endotracheal connector.of the obstruction,  the tracheal tube connector, wasretained in the process of attempting to relieve theobstruction by changing equipment. These two casereports illustrate very clearly the dangers of failing toeliminate the “whole” circuit (including tracheal tubeconnectors, filters, etc) when dealing with a case ofunexpected airway obstruction.3. Check the “Whole” CircuitIt is recommended pre-anaesthetic practice tocheck the anaesthetic breathing circuit. The Aus-tralian and New Zealand College of Anaesthetistspolicy document “Protocol for Checking theAnaesthetic Machine” (ref. 11) paragraph 2.2.2.4.2describes a two bag (simulated lung) technique as therecommended process for checking the integrity ofthe circle system. The authors recommend that theprocess of testing the anaesthetic breathing circle asoutlined in the above policy document should includeperforming the “two bag” test on the whole circuit,including tracheal tube connectors and filters.Further, it is suggested that checking of the trachealtube, laryngeal mask airway, cuffed oropharyngealairway and face mask include a visual and physicalinspection of patency.REFERENCES1. JA Roelofse, EA Shipton. Obstruction of a breathing circuit—A case report. SA Medical Journal (29 September) 1984;66:501-502.2. CS Dutton. A bizarre cause of obstruction in an Oxford Non-Kink Endotracheal Tube. Anaesthesia 1962; 17:395-396.3. B Roy, B Barman, C Dutta, SM Basu. An unusual foreign bodyobstructing endotracheal tube connector. J Indian MedicalAssociation (Sep) 1995;  93(9):358.4. PRH Wilkes, PA Lindsay. Bain circuit occluded by foreignbody. Can J Anaesth 1994; 41(2):137-139.5. HN Ng, BC Ong. Reusable Robertshaw tube (letter). AnaesthIntensive Care 1998; 26(2):224.6. BP Gallacher, M Kelly, RR Mora. Failure to Ventilate Due toGlass Ampoule Fragment Occlusion of the Breathing Circuit(letter). Anesthesiology 1997;  87:180.7. TJ Krensavage, E Richards. Sudden development of anesthesiacircuit obstruction by an end-tidal CO2 cap in the gas samplingelbow (letter). Anesth Analg 1995; 81:207.8. PH Norman, MD Daley, JR Walker, S Fusetti. Obstruction dueto retained carbon dioxide absorber canister wrapping. AnesthAnalg 1996; 83:425-426.9. W. B. Runciman. Crisis Management. Anaesth Intensive Care1988; 16:86-88.10. WB Runciman et al. Crisis Management—Validation of anAlgorithm by Analysis of 2000 Incident Reports. AnaesthIntensive Care 1993; 21:579-592.11. The Australian and New Zealand College of AnaesthetistsPolicy Document, Protocol for Checking the AnaestheticMachine. PS31 (1997).75 CASE REPORTAnaesthesia and Intensive Care, Vol. 27, No. 1, February 1999

A bizarre cause of obstruction in an Oxford NonKink Endotracheal Tube. Anaesthesia

An unusual foreign body obstructing endotracheal tube connector.

Bain circuit occluded by foreign body.

Crisis Management—Validation of an Algorithm by Analysis of

Crisis Management. Anaesth Intensive Care

Failure to Ventilate Due to Glass Ampoule Fragment Occlusion of the Breathing Circuit (letter). Anesthesiology

Obstruction due to retained carbon dioxide absorber canister wrapping. Anesth Analg

Obstruction of a breathing circuit— A case report.

Reusable Robertshaw tube (letter). Anaesth Intensive Care

Sudden development of anesthesia circuit obstruction by an end-tidal CO2 cap in the gas sampling elbow (letter). Anesth Analg

The Australian and New Zealand College of Anaesthetists Policy Document, Protocol for Checking the Anaesthetic Machine.

Anaesthetic breathing circuit obstruction due to blockage of tracheal tube connector by a foreign body - two cases

Anaesthetic breathing circuit obstruction due to blockage of tracheal tube connector by a foreign body - two cases

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Anaesthetic breathing circuit obstruction due to blockage of tracheal tube connector by a foreign body - two cases

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