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Anaesthetic equipment for thoracic surgery
THORACIC
Anaesthetic equipment for thoracic surgery John W W Gothard
In 1931, Gale and Waters were the first to describe endobronchial intubation in clinical practice. Magill developed right and left single-lumen endobronchial tubes. Little changed until the introduction of the double-lumen endobronchial Carlens tube in 1949. This was initially used for differential bronchospirometry but was adapted and used for selective ventilation during thoracic surgery; it is still used in some centres. It has a carinal hook, which in theory prevents placement of the tube too far distally but can also make laryngeal intubation difficult. Robertshaw, a Manchester anaesthetist, developed his own pattern of left and right doublelumen endobronchial tube in 1962. This design omitted the carinal hook of the Carlens tube and incorporated larger D-shaped lumina. The right-sided Robertshaw tube included a ventilation slot in the bronchial cuff to accommodate the early take-off of the right upper lobe from the main bronchus on this side. In current practice, selective one-lung ventilation during thoracic surgery is most commonly achieved with a double-lumen endobronchial tube. These tubes also prevent spill-over of blood and infected secretions from one lung to another. Bronchial blockade can also be used to separate the lungs and there has recently been a resurgence of interest in this technique.
Double-lumen endobronchial tubes Double-lumen tubes are similar to the original Robertshaw tube (Figure 1). In the UK, the two most widely used tubes are the Robertshaw (Phoenix Medical) and the Bronchocath (Mallinckrodt). Many other manufacturers (e.g. Rusch, Portex, Sheridan) also make double-lumen tubes. Robertshaw tubes are available in four sizes, ranging from large to extra-small. Bronchocath tubes are available in French gauge sizes of 35, 37, 39 and 41, with a small 28 tube for left endobronchial intubation only. Modern versions of both types of tube are disposable. The Robertshaw tube is made of rubber with a smooth outer coating, and the Bronchocath tube is made of polyvinylchloride (PVC). Both tubes are made in right and left forms, shaped
John W W Gothard is Consultant Cardiothoracic Anaesthetist at the Royal Brompton Hospital, London. He qualified from St Mary’s Hospital Medical School, London. He has written several textbooks on cardiac and thoracic anaesthesia and has a major interest in thoracic anaesthesia and anaesthesia for congenital heart disease.
ANAESTHESIA AND INTENSIVE CARE MEDICINE 6:12
425
© 2005 The Medicine Publishing Company Ltd
THORACIC
Univent tube – combined tracheal tube and bronchial blocker
Basic pattern of a right-sided double-lumen endobronchial tube Bronchial limb Tracheal limb
Distal end of hollow bronchial blocker
Pilot balloon – bronchial cuff
Bronchial blocker cuff inflated
Pilot balloon – tracheal cuff
Tracheal cuff Oropharyngeal curve
Distal main lumen
Tracheal ventilation lumen for left lung
Main cuff inflated Pilot tube to bronchial blocker cuff
Bronchial curve Capped proximal end of hollow bronchial blocker
Bronchial cuff
Ventilation slot for right upper lobe Endobronchial ventilation lumen to middle and lower lobes From: Gothard J W W. Anaesthesia for thoracic surgery. 2nd ed. Oxford: Blackwell Scientific Publications, 1993
Proximal main lumen Pilot tube to main cuff
1
2
to allow placement in the appropriate bronchus (Figure 1). There are two pilot balloons that allow inflation of tracheal and bronchial cuffs. The bronchial pilot balloons and cuffs are blue for easy identification. The right-sided Robertshaw tube has a ventilation slot built into the bronchial cuff. The equivalent Bronchocath tube has a ventilation slot distal to an eccentrically placed bronchial cuff. In general, the ventilation slot of the Robertshaw tube is larger than that of an equivalent size of Bronchocath tube and there is evidence that right upper lobe ventilation can be achieved more reliably with the Robertshaw tube.
Placement and position check Double-lumen tubes are inserted into the airway using standard laryngoscopy with the tip of the tube pointing anteriorly/upwards. Once past the vocal cords the tube is rotated to the appropriate side and advanced until it is in place. The tracheal cuff is then inflated and the seal checked. The tracheal limb of the tube is then opened to air, via the upper suction cap, and the appropriate catheter mount clamped, leaving only the bronchial limb ventilated. The bronchial cuff is then inflated with the minimum amount of air to ensure cuff seal. Any gas leak should be eliminated from the intubated bronchus. This is detected as gas passing up the open tracheal limb. It should be remembered that bronchial rupture has been reported with double-lumen tube insertion, particularly on the left side. Correct positioning of the tube is confirmed by auscultation and observation of chest movements. Particular attention should be paid to the ventilation of the upper lobe zones, which can easily be obstructed by a misplaced tube. In addition, the above checks should be repeated after positioning the patient for surgery. Doublelumen tubes are also known to migrate intraoperatively because they soften at body temperature and if the airway is handled surgically. An increased airway pressure or change in flow/volume loop configuration may warn of this occurrence before arterial desaturation.
Type and size of tube It is preferable to use a left-sided double-lumen tube where possible. In UK practice, a right-sided tube is used if lung resection is to be undertaken on the left. In most other instances, including video-assisted thoracic surgery, a left-sided tube is used to obviate the problem of right upper lobe ventilation. The size of tube selected and the insertion depth depend on the height, weight, body build and gender of the patient. Cohen has stated (see Further Reading) that a 37 FG tube can be placed in most women, while a 39 FG tube is used in the average man. However, the problem is not quite so simple. Bronchocath tubes are long and not designed to be inserted to ‘the hilt’. Robertshaw tubes are designed to be inserted so that the bite-block (above which the tracheal and endobronchial portions separate) is approximately at the level of the patient’s teeth. Even with this design feature, a large Robertshaw tube can easily be advanced too far in a large patient with a short neck so that an upper lobe is occluded. It has been suggested that a double-lumen tube should be inserted to a depth of 29 cm (from the teeth) in men and women 170 cm in height and that this depth should be increased 1 cm for each 10 cm increment in height of the patient. The solution to these problems is to use a fibre-optic bronchoscope to check the position of the double-lumen tube.
ANAESTHESIA AND INTENSIVE CARE MEDICINE 6:12
Bronchial blockade Bronchial blockers have been used intraoperatively for many years to block individual lobes and to facilitate one-lung ventilation by blocking a main bronchus. Several devices, including Fogarty embolectomy catheters and urinary catheters, have been used as improvised bronchial blockers. There has been a renaissance in interest in using bronchial blockade over the last decade, particularly in Japan and North America. This has led to the development 426
© 2005 The Medicine Publishing Company Ltd
THORACIC
Bronchial blockade of the right upper lobe achieved with a Univent tube under fibre-optic bronchoscopic control
Fibre-optic bronchoscopy used to check the position of a left-sided double-lumen tube Innermost acceptable position
Univent tube
Herniating cuff Fibre-optic bronchoscope Outermost acceptable position
Fibre-optic bronchoscope
3
5
of a combined tracheal tube and bronchial blocker, the Univent tube, and the commercial availability of single endobronchial blockers such as that developed by Arndt.
Fibre-optic bronchoscopy Fibre-optic bronchoscopes and multi-purpose fibre-optic anaesthetic laryngoscopes (e.g. Olympus LF-2) are readily available. Therefore, it is easy to perform routine direct-vision assessment of endobronchial tube and bronchial blocker placement. The introduction of robust paediatric fibre-optic bronchoscopes (e.g. Olympus LF-P) allows this to be carried out with the smallest tubes. The fibre-optic bronchoscope can be used at the outset of a procedure to aid in a difficult laryngeal intubation or it can be used to ‘rail-road’ an endobronchial tube into the appropriate bronchus under direct vision. More often it is used to check the position of double-lumen tubes following blind placement (Figure 5). Some authors consider this step to be mandatory. A previously placed double-lumen tube is checked by first passing the fibre-optic bronchoscope down the tracheal lumen to ensure a clear view of the non-intubated bronchus (i.e. no cuff herniating across the carina). It is then passed down the bronchial lumen to ensure that the left upper lobe is not obstructed or, alternatively, that the ventilation slot in a right-sided tube is opposed to the right upper lobe orifice. These checks should be repeated if the tube is repositioned and after the patient has been turned into the lateral thoracotomy position. Fibre-optic bronchoscopy may also become necessary if ventilation problems occur intraoperatively. It is essential to maintain and observe full monitoring of the patient during fibre-optic bronchoscopy.
The Univent tube The Univent tube comprises a tracheal tube with a bronchial blocker (Figure 2). It was introduced into clinical practice by Inoue in 1982 and is probably the most commonly used blocker. The tube is made in a variety of sizes. It comprises a tracheal tube with a moveable blocker inserted through the anterior wall. The tube is placed in the trachea in the usual way and the blocker advanced, preferably under fibre-optic bronchoscopic control, to block the appropriate main or lobar bronchus (Figure 3). This blocker has the advantage that individual lobes can be blocked, but other potential advantages seem theoretical (Figure 4).
Advantages and disadvantages of the Univent tube Advantages • Lobar blockade possible • Ease of use for difficult intubation • Facilitates easy suction of secretions • Eliminates tube change if ventilation required postoperatively Disadvantages • Less versatile than double-lumen tube • Blocker can migrate • More expensive than double-lumen tube • Inflation/deflation of lung more difficult
FURTHER READING Cohen E. Methods of lung separation. Curr Opinion Anaesthesiol 2002; 15: 69–78. Slinger P. Fiberoptic positioning of double-lumen tubes. J Cardiothoracic Anesthesia 1989; 3: 486–96.
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ANAESTHESIA AND INTENSIVE CARE MEDICINE 6:12
427
© 2005 The Medicine Publishing Company Ltd
Anaesthetic equipment for thoracic surgery John W W Gothard
In 1931, Gale and Waters were the first to describe endobronchial intubation in clinical practice. Magill developed right and left single-lumen endobronchial tubes. Little changed until the introduction of the double-lumen endobronchial Carlens tube in 1949. This was initially used for differential bronchospirometry but was adapted and used for selective ventilation during thoracic surgery; it is still used in some centres. It has a carinal hook, which in theory prevents placement of the tube too far distally but can also make laryngeal intubation difficult. Robertshaw, a Manchester anaesthetist, developed his own pattern of left and right doublelumen endobronchial tube in 1962. This design omitted the carinal hook of the Carlens tube and incorporated larger D-shaped lumina. The right-sided Robertshaw tube included a ventilation slot in the bronchial cuff to accommodate the early take-off of the right upper lobe from the main bronchus on this side. In current practice, selective one-lung ventilation during thoracic surgery is most commonly achieved with a double-lumen endobronchial tube. These tubes also prevent spill-over of blood and infected secretions from one lung to another. Bronchial blockade can also be used to separate the lungs and there has recently been a resurgence of interest in this technique.
Double-lumen endobronchial tubes Double-lumen tubes are similar to the original Robertshaw tube (Figure 1). In the UK, the two most widely used tubes are the Robertshaw (Phoenix Medical) and the Bronchocath (Mallinckrodt). Many other manufacturers (e.g. Rusch, Portex, Sheridan) also make double-lumen tubes. Robertshaw tubes are available in four sizes, ranging from large to extra-small. Bronchocath tubes are available in French gauge sizes of 35, 37, 39 and 41, with a small 28 tube for left endobronchial intubation only. Modern versions of both types of tube are disposable. The Robertshaw tube is made of rubber with a smooth outer coating, and the Bronchocath tube is made of polyvinylchloride (PVC). Both tubes are made in right and left forms, shaped
John W W Gothard is Consultant Cardiothoracic Anaesthetist at the Royal Brompton Hospital, London. He qualified from St Mary’s Hospital Medical School, London. He has written several textbooks on cardiac and thoracic anaesthesia and has a major interest in thoracic anaesthesia and anaesthesia for congenital heart disease.
ANAESTHESIA AND INTENSIVE CARE MEDICINE 6:12
425
© 2005 The Medicine Publishing Company Ltd
THORACIC
Univent tube – combined tracheal tube and bronchial blocker
Basic pattern of a right-sided double-lumen endobronchial tube Bronchial limb Tracheal limb
Distal end of hollow bronchial blocker
Pilot balloon – bronchial cuff
Bronchial blocker cuff inflated
Pilot balloon – tracheal cuff
Tracheal cuff Oropharyngeal curve
Distal main lumen
Tracheal ventilation lumen for left lung
Main cuff inflated Pilot tube to bronchial blocker cuff
Bronchial curve Capped proximal end of hollow bronchial blocker
Bronchial cuff
Ventilation slot for right upper lobe Endobronchial ventilation lumen to middle and lower lobes From: Gothard J W W. Anaesthesia for thoracic surgery. 2nd ed. Oxford: Blackwell Scientific Publications, 1993
Proximal main lumen Pilot tube to main cuff
1
2
to allow placement in the appropriate bronchus (Figure 1). There are two pilot balloons that allow inflation of tracheal and bronchial cuffs. The bronchial pilot balloons and cuffs are blue for easy identification. The right-sided Robertshaw tube has a ventilation slot built into the bronchial cuff. The equivalent Bronchocath tube has a ventilation slot distal to an eccentrically placed bronchial cuff. In general, the ventilation slot of the Robertshaw tube is larger than that of an equivalent size of Bronchocath tube and there is evidence that right upper lobe ventilation can be achieved more reliably with the Robertshaw tube.
Placement and position check Double-lumen tubes are inserted into the airway using standard laryngoscopy with the tip of the tube pointing anteriorly/upwards. Once past the vocal cords the tube is rotated to the appropriate side and advanced until it is in place. The tracheal cuff is then inflated and the seal checked. The tracheal limb of the tube is then opened to air, via the upper suction cap, and the appropriate catheter mount clamped, leaving only the bronchial limb ventilated. The bronchial cuff is then inflated with the minimum amount of air to ensure cuff seal. Any gas leak should be eliminated from the intubated bronchus. This is detected as gas passing up the open tracheal limb. It should be remembered that bronchial rupture has been reported with double-lumen tube insertion, particularly on the left side. Correct positioning of the tube is confirmed by auscultation and observation of chest movements. Particular attention should be paid to the ventilation of the upper lobe zones, which can easily be obstructed by a misplaced tube. In addition, the above checks should be repeated after positioning the patient for surgery. Doublelumen tubes are also known to migrate intraoperatively because they soften at body temperature and if the airway is handled surgically. An increased airway pressure or change in flow/volume loop configuration may warn of this occurrence before arterial desaturation.
Type and size of tube It is preferable to use a left-sided double-lumen tube where possible. In UK practice, a right-sided tube is used if lung resection is to be undertaken on the left. In most other instances, including video-assisted thoracic surgery, a left-sided tube is used to obviate the problem of right upper lobe ventilation. The size of tube selected and the insertion depth depend on the height, weight, body build and gender of the patient. Cohen has stated (see Further Reading) that a 37 FG tube can be placed in most women, while a 39 FG tube is used in the average man. However, the problem is not quite so simple. Bronchocath tubes are long and not designed to be inserted to ‘the hilt’. Robertshaw tubes are designed to be inserted so that the bite-block (above which the tracheal and endobronchial portions separate) is approximately at the level of the patient’s teeth. Even with this design feature, a large Robertshaw tube can easily be advanced too far in a large patient with a short neck so that an upper lobe is occluded. It has been suggested that a double-lumen tube should be inserted to a depth of 29 cm (from the teeth) in men and women 170 cm in height and that this depth should be increased 1 cm for each 10 cm increment in height of the patient. The solution to these problems is to use a fibre-optic bronchoscope to check the position of the double-lumen tube.
ANAESTHESIA AND INTENSIVE CARE MEDICINE 6:12
Bronchial blockade Bronchial blockers have been used intraoperatively for many years to block individual lobes and to facilitate one-lung ventilation by blocking a main bronchus. Several devices, including Fogarty embolectomy catheters and urinary catheters, have been used as improvised bronchial blockers. There has been a renaissance in interest in using bronchial blockade over the last decade, particularly in Japan and North America. This has led to the development 426
© 2005 The Medicine Publishing Company Ltd
THORACIC
Bronchial blockade of the right upper lobe achieved with a Univent tube under fibre-optic bronchoscopic control
Fibre-optic bronchoscopy used to check the position of a left-sided double-lumen tube Innermost acceptable position
Univent tube
Herniating cuff Fibre-optic bronchoscope Outermost acceptable position
Fibre-optic bronchoscope
3
5
of a combined tracheal tube and bronchial blocker, the Univent tube, and the commercial availability of single endobronchial blockers such as that developed by Arndt.
Fibre-optic bronchoscopy Fibre-optic bronchoscopes and multi-purpose fibre-optic anaesthetic laryngoscopes (e.g. Olympus LF-2) are readily available. Therefore, it is easy to perform routine direct-vision assessment of endobronchial tube and bronchial blocker placement. The introduction of robust paediatric fibre-optic bronchoscopes (e.g. Olympus LF-P) allows this to be carried out with the smallest tubes. The fibre-optic bronchoscope can be used at the outset of a procedure to aid in a difficult laryngeal intubation or it can be used to ‘rail-road’ an endobronchial tube into the appropriate bronchus under direct vision. More often it is used to check the position of double-lumen tubes following blind placement (Figure 5). Some authors consider this step to be mandatory. A previously placed double-lumen tube is checked by first passing the fibre-optic bronchoscope down the tracheal lumen to ensure a clear view of the non-intubated bronchus (i.e. no cuff herniating across the carina). It is then passed down the bronchial lumen to ensure that the left upper lobe is not obstructed or, alternatively, that the ventilation slot in a right-sided tube is opposed to the right upper lobe orifice. These checks should be repeated if the tube is repositioned and after the patient has been turned into the lateral thoracotomy position. Fibre-optic bronchoscopy may also become necessary if ventilation problems occur intraoperatively. It is essential to maintain and observe full monitoring of the patient during fibre-optic bronchoscopy.
The Univent tube The Univent tube comprises a tracheal tube with a bronchial blocker (Figure 2). It was introduced into clinical practice by Inoue in 1982 and is probably the most commonly used blocker. The tube is made in a variety of sizes. It comprises a tracheal tube with a moveable blocker inserted through the anterior wall. The tube is placed in the trachea in the usual way and the blocker advanced, preferably under fibre-optic bronchoscopic control, to block the appropriate main or lobar bronchus (Figure 3). This blocker has the advantage that individual lobes can be blocked, but other potential advantages seem theoretical (Figure 4).
Advantages and disadvantages of the Univent tube Advantages • Lobar blockade possible • Ease of use for difficult intubation • Facilitates easy suction of secretions • Eliminates tube change if ventilation required postoperatively Disadvantages • Less versatile than double-lumen tube • Blocker can migrate • More expensive than double-lumen tube • Inflation/deflation of lung more difficult
FURTHER READING Cohen E. Methods of lung separation. Curr Opinion Anaesthesiol 2002; 15: 69–78. Slinger P. Fiberoptic positioning of double-lumen tubes. J Cardiothoracic Anesthesia 1989; 3: 486–96.
4
ANAESTHESIA AND INTENSIVE CARE MEDICINE 6:12
427
© 2005 The Medicine Publishing Company Ltd