Pressure transducers Pressure transducers constantly measure pre- and post- oxygenator pres sures. A high post-oxygenator pressure signi \201 es a cannula obstruction, and an increas ing pressure drop across the oxygenator implies membrane lung failure. Cannulation Cannulation for VV is percutaneous. The patient must be anesthetized and paraly zed to reduce the risk of air embolism. Types of ECMO There are two types: venoarterial ECMO (VA ECMO) and venovenous ECMO (VV ECMO ). VA ECMO drains deoxygenated blood from a central vein or right atrium and returns it to a central artery. This \202 ow is in addition to the native cardiac output, hence there i s partial cardiac support. VV ECMO drains blood from a central vein or right atrium and ret urns the oxygenated blood back to a large vein. The volumes of blood drained from and re-in fused into the venous system are equal, therefore there is no change in CVP or ventricular \201 lling; the pulmonary artery pressure usually falls due to the increased venous oxyge n tension. Native cardiac output provides the full systemic blood \202 ow, which usually improves with the reduction in airway pressure. VV ECMO is preferred to VA ECMO in the trea tment of respiratory failure as normal pulmonary blood \202 ow is maintained. ECMO patient management Maintain haemostasis The principle is to balance the anticoagulatio n so as to pre- vent signi \201 cant circuit thrombus formation without causing major hemo rrhage. The main agent used is heparin. Anticoagulation is initiated with a bolus of 75 uni ts/kg of heparin IV followed by an infusion to achieve an activated clotting time of 180 \200\223200s. The international normalized ratio (INR), \201 brinogen levels and platelet count should also be monitored and corrected. Progressive elevation of D-dimers can indica te thrombolytic activity related to the circuit or patient. Allow lung recovery by use of gentle ventilation. Once on ECMO, the high pre-ECMO ventilato r settings are gradually decreased to \200\230rest settings \200\231 which is positive ins piratory presure (PIP) 20 \200\22325, PEEP 10 \200\22315cm H2O, FiO2 0.3, and rate 10/min. The aim is to reduce ventilator- induced barotrauma and oxygen toxicity. The ECMO circuit The ECMO circuit consists of cannulae, pump, membrane lung, servo-regulato r, heat exchanger, pressure transducers and a bridge. It is designed to eliminate areas of stasis so that only small amounts of anticoagulation are required. Provide adequate systemic oxygen delivery Oxygen delivery is dependent on : \200 \200 \200 \200 \200 Capacity (rated \202 ow) of membrane oxygenator Oxygen binding capacity of blood Flow thr ough circuit Oxygen uptake through native lung Cardiac output Oxygenator The key component of the circuit is the oxygenator or membrane lung. Modern circ uits use non-porous hollow \201 bre oxygenators (polymethylpentene). They have much bette r gas exchange, lower priming volume and resistance, and are more biocompatible than previo us silicone devices. Oxygen content of blood = (1.39 x Hb x % saturations) + dissolved Hb (minimal and usually i gnored) Cannulae The amount of oxygen delivered by the ECMO circuit is related to the oxygen conten t of the blood and the ECMO circuit \202 ow. This is limited by the size and number of ve nous drainage cannulae. The shortest widest cannula possible should be used. On ECMO, to maximize oxygen delivery, the oxygen content of blood needs to be optimized by maintaining a normal Hb concentration of 12 \200\22314g/dl. Within the range of the rated \202 ow (design maximum for the oxygenator), increasing the \202 ow can increase oxygena tion. Oxygenation is assessed during VV ECMO using the arterial PaO2 and SpO2. Carbon dioxi de removal Carbon dioxide clearance is more ef \201 cient than oxygen uptake because unlik e oxygen it is diffusion dependent. As the sweep gas contains no carbon dioxide, the diffus ion gradient is highest at the inlet end of the oxygenator. Increasing the sweep gas \202 ow will clear more carbon dioxide. Pump The pump pulls bloods either from a small compliance chamber (bladder) or directly fro m the patient, pumps it through the oxygenator and then back to the patient. It is vital to have a mechanism preventing negative pressure developing proximally when the venous \202 ow is inadequate as this pressure, if unchecked, can cause damage to the atrium and vessel wall as it is \200\230sucked in \200\231. It can also cause haemolysis and cavitation as gas is pulled out of solution. 33 CHAPTER 1.14 ECMO for adults in respiratory failure conditions such as pulmonary \201 brosis are excluded as they are unlikely to recover wit h ECMO support. Though carbon dioxide removal is relatively independent of blood \202 ow rate it is depen dent on the surface area of the gas-exchanging membrane. When the effective gas exchange ar ea decreases, CO2 clearance is affected before oxygenation is. Evidence The CESAR (Conventional Ventilation or ECMO for Severe Adult Respiratory failure) trial is a multi-center RCT conducted in the UK It evaluates survival without severe disabi lity at 6 months and the cost \200\223bene \201 ts of ECMO vs conventional ventila- tion. A total of 180 patients were recruited and the result is currently awaited. The only other trial dates back to the 1970s. This was a multi-center trial sponsored by the National Inst itutes of Health and it compared VA ECMO with conventional ventilation in adults. This tria l did not show any difference in outcome, but case selection, ECMO techniques and technolog y, and ventilation strategies in this trial have been superseded by modern protocols. ECMO is an evidence-based therapy for neonates with severe respiratory failure. The ELSO registr y (1990 \200\2232006) shows a 59% survival for adult ECMO patients with respiratory failure , and our experience in Glen \201 eld (Leicester UK) is similar, with a survival of 66%. Intensive care Normal intensive care principles apply to ECMO patients. Full nutrition and appropriate use of antibiotics, steroids and other drugs are essential. In addition to an I ntensive Care Nurse, there is an ECMO specialist with the patient and circuit at all times. The ECMO specialist is trained in the management of ECMO circuit and any potential com- pl ications. Weaning, \200\230trial off \200\231 and decannulation The ECMO \202 ow rate is reduced as the patient gets better. This is shown by improved gas exchange, lung compliance and rad iological appearance. Once the \202 ow has come down to 1l/min the patient is usually rea dy to come off ECMO. To trial off VV ECMO, the patient is ventilated using optimum settings and the oxygen supply to the membrane oxygenator is disconnected. If the patient is stable for 2h, the cannulae can be removed. Conclusion ECMO is a rational treatment for adult respiratory failure in patients who have failed conventional treatment. The CESAR trial will further de \201 ne the role of ECMO in these patients. Complications The main complication of ECMO is bleeding. The main potential areas for bleed ing are gastrointestinal, intracra- nial and pulmonary, as well as cannulation sites. Bleed ing should be anticipated and actively prevented. Experienced medical staff should be invol ved in all procedures. Other complications are associated with cannulation, which includes pneumothorax, haemothorax, pericardial tamponade, vascular tears, embolization and complica tions associated with the circuit, including cannula obstruction, clots or air in the circu it, oxygenator failure and tubing rupture. Further reading ELSO. Extracorporeal cardiopulmonary support in critical care, 3rd edn. Ext racorporeal Life Support Organization, Ann Arbor, MI, 2005. Kolla S, Awad SS, Rich PB, et al. Extracorporeal life support for 100 adult patients with s evere respiratory failure. Ann Surg 1997; 226: 544 \200\22366. Peek GJ, Moore HM, Moore N, et al. Extracorporeal membrane oxygenation for adult respirator y failure. Chest 1997; 112: 759 \200\22364. Indications of ECMO 1 Severe respiratory failure. 2 Potentially reversible underlying condi tion. 3 Failed or failing conventional treatment. The reversibility of respiratory failure is dif \201 cult to deter- mine in adults. Patients ventilated with high pressure, PIP >30 cm H2O and high FiO2 >0.8 for more than 7 days, patients with advanced chronic lung disease and irreversible UK Collaborative Trial Group. UK Collaborative randomized trail of neonatal extra corporeal membrane oxygenation. Lancet 1996; 348: 75 \200\22382. Zapol WM, Snider MT, Hill JD et al/ Extracorporeal membrane oxygenation in severe respirato ry failure. A randomized prospective study. JAMA 1979; B: 2193 \200\2236. 34 A BODENHAM Tracheostomy Minitracheostomy/cricothyroidotomy Introduction Mini-tracheostomy is a term used to describ e the insertion of a small-bore non-cuffed tube through the cricothyroid membrane (usually 4mm internal diameter), principally to aid the clearance of secretions. The passage of suct ion catheters stimulates coughing and allows secretions to be aspirated. As a short-term me asure these devices may help to prevent the need for naso/orotracheal intubation and assist ed ventilation. The small size of the tube limits its value, and the use of mini-tracheosto my has declined in many centers in recent years. Cricothyroidotomy is a life-saving procedu re used to pro- vide emergency access to the airway (e.g. following obstruction of the uppe r airway) when measures such as bag and mask ventilation and translaryngeal intubation have failed. It involves the insertion of a small tube through the cricothyroid membrane, throu gh which oxygen/ventila- tion can be provided until a de \201 nitive airway is obtained. A cuffed device is desirable, and a 6mm rather than 4mm internal diameter greatly improves s uctioning and ventila- tion capacity. Both cricothyroidotomy and mini-tracheostomy kits are commercially available. The technique for the insertion of each is essentially the same. Early complications \200 \200 \200 \200 \200 \200 Bleeding (may lead to total airway obstruction) Pneumothorax Tube misplacement or dislodgem ent Emphysema Mucus plugging/obstruction Stomal inefection Late complications \200 \200 \200 \200 Tracheal stenosis Tracheo-oesophageal \201 stula Skin tethering/scarring Hemorrhage from innominate vessels Tracheostomy Introduction Tracheostomy is a common procedure in intensive care. The most co mmon problems, in both general wards and critical care, are related to obstruction or displ acement. The indications for temporary tracheostomy in intensive care include treatment for upper airway obstruction, the avoidance of the laryngeal complications of prolonged endotr acheal intubation and the continued need to protect and maintain the airway in patients wit h severe neurological injury. The development of percutaneous techniques that enable a trac heostomy tube to be inserted by the critical care physician as a bedside procedure has resu lted in temporary tracheostomy becoming more commonplace. Relative contraindications \200 \200 \200 Coagulopathy Abnormal neck anatomy Uncooperative patient Insertion A tracheostomy may be performed surgically or percuta- neously, and as an emergen cy or elective procedure. Technique Explain to the patient what you are going to do. Get writ- ten or verbal consent if appropriate. Check the patient \200\231s coagulation status. Position the patient comfor tably with the head and neck extended over a pillow. \200 \200 \200 Indications for a tracheostomy \200 \200 Aid to weaning from assisted ventilation Tracheal access to remove thick pulmonary secretio ns (easier suction than translaryngeal intubation) Long-term airway management Bypass of up per airway obstruction (e.g. patients with trauma, infection, malignancy, laryngeal or subg lottic stenosis, bilateral recurrent laryngeal nerve palsy, severe sleep apnoea) Prevention of pulmonary aspiration (e.g. patients with laryngeal incompetence, bulbar dysfunction (e. g. cere- brovascular accidents, Parkinson disease)) Neuromuscular disorders (e.g. Guillain \200\223Barre syndrome, critical illness neuromyopathy) Severe brain injury, reversible or irreversible Trauma or surgery in the face/neck region Palpate anatomy to identify the cricothyroid membrane. Clean the neck with antiseptic solut ion. In \201 ltrate over the cricothyroid membrane with 2 \200\2233ml of local anesthetic. Warn the patient that you are going to make him or her cough and perform cricothyroid punc ture with a green 21-gauge needle. Aspirate air to con \201 rm the tracheal position of th e needle and rapidly inject 2ml of lidocaine (lignocaine). Wait for coughing to subside. Pe rform a super \201 cial skin incision. Pass the introducing needle into the trachea and as pir- ate air. Pass the guide wire through the needle and then remove the needle. Pass the i ntroducing dilator(s) over the guide wire and then slide the cricothyroidotomy/mini-tracheo stomy tube off the introducer. Remove the introducer and guide wire together, leaving the c ricothyroidotomy/mini- tracheostomy in place. Suction to remove any blood. Obtain a chest X -ray (CXR) to verify the position, appre- ciating the limitations of such imaging. \200 \200 \200 Relative contraindications for percutaneous dilatational tracheostomy (PDT) \200 \200 \200 \200 \200 \200 \200 \200 Children <12yrs old Uncorrectable coagulopathy Active infection over the anterior neck Loca l malignancy in trachea Unstable cervical spine fracture Morbid obesity (BMI >35) Gross ana tomical distortion of the neck Previous neck surgery or tracheostomy Complications The complications of mini-tracheostomy are the same as for formal tracheostom y. Misplacement and bleeding are particular problems. 35 CHAPTER 1.15 Tracheostomy \200 \200 \200 \200 \200 leak develops, as well as for con \201 rmation of correct needle and subsequent tracheosto my placement. Previous radiotherapy to the neck Extensive burns to the neck Requirement for high PEEP >15 cm H2O or FiO2 >0.6. Haemodynamic instability Raised ICP Patient unlikely to survive >48h Ultrasound Ultrasound scanning of the neck prior to percutaneous tracheostomy allows visual ization of anterior neck struc- tures, particularly the assessment of blood vessels, of and depth, level of rings and angulation of the trachea. Useful information about adjacent str uctures helps with the risk- bene \201 t analysis of an open vs percutaneous tracheostomy. Imaging can guide needles and dilators away from at-risk structures. Provision of information and consent/assent Few patients within intensive care have the cap acity to give informed consent, but attempts should be made to seek their understanding and approval where this is possible. The role of the next of kin in healthcare decision making is being formalized under the new Mental Capacity Act (England and Wales) and the Adults w ith Incapacity Act (Scotland). Current directives from the GMC and Department of Health spe cify their involvement using Consent Form 4; \200\230Form for Adults who are Unable to Con sent to Investigation or Treatment \200\231. This process requires provi- sion of informati on on the nature of the procedure, proposed bene \201 ts, potential hazards and alternativ es. Endoscopy A \202 exible \201 breoptic scope passed through the tracheal tube may be use d to guide correct placement of the introducer needle, guide wire and tracheostomy tube. Di rect visualization should reduce tracheal wall damage and tube misplacement. The presence o f a scope may hinder ventilation, increasing the risk of hypoxia and hyper- carbia with ass ociated increase in ICP in susceptible patients. It should be appreciated that bleeding, di stortion of structures and obstruction of the visual \201 eld with larger dilators may pr event endoscopic visualization of damage until after it has occurred. Also the section of t rachea adjacent to the tracheostomy tube cannot be easily visual- ized after tube insertion . Alternative approaches include the use of a semi-rigid, small-diameter scope, such as a B on \201 l \200\231s laryngoscope or optical stylets, which interferes less with ventilatio n and avoids potential expensive damage to a \202 exible bronchoscope by needle puncture. Monitoring Routine monitoring of ECG and oxygen saturation, and invasive blood pressure mon itoring should be in place given the potential for abrupt changes in blood pressure with ei ther administration of anesthetic agents or the stimulation of the procedure. An arterial l ine is also indi- cated for arterila blood gas analysis, since capnography may be unreliabl e in the presence of inadequate ventilation due to obstruction of the ETT by the bronchosco pe or loss of tidal volume by the inevitable leak as the stoma is created. Capnography shou ld be considered mandatory given the potential for accidental extubation, and subsequent ne ed for re-intubation, assessment of the adequacy of ventilation with obstruction of the air way by a bronchoscope or as a Post-procedure CXR? The usefulness of a CXR is debatable. It should be appreciated that tra cheal placement cannot be inferred from a plain X-ray. A tube that is partially kinked or t oo short may be identi \201 ed from plain \201 lm. 36 A BODENHAM Aftercare of the patient with a tracheostomy Aftercare Meticulous skin care at the stoma site has been suggested to decrease bacterial c ontamination and the in \202 ammatory response leading to granulation tissue. Adequate hum idi \201 - cation, tracheal suctioning and physiotherapy are essential to avoid obstructio n of tracheostomy tubes. The obstruc- tion of tracheostomy tubes can be static, due to thic k tena- cious secretion, or dynamic, due to partial obstruction by the membranous posterior wall encroaching on the tra- cheostomy tube lumen. The degree of dynamic obstruc- tion app ears to increase when the intrathoracic pressure increases. Dynamic obstruction can be prev ented by a properly designed tube with optimum length and angle to ensure correct tracheost omy tube positioning within the trachea. Tracheostomy tubes with an inner cannula require t hem to be regularly removed for cleaning, to maintain tube patency. Tubes without inner can nulae should be exchanged every 7 \200\22314 days, or more frequently if secretions build u p. A tracheostomy tube blocked with tenacious secretions renders the patient at risk of pro gressive hypoxia and possibly cardiorespiratory arrest. Resuscitation attempts will be unsu ccessful unless the airway obstruction is recog- nized and treated promptly. Removal of the tracheostomy tube may be required if suctioning fails to clear the obstruc- tion. In the s hort term, spontaneously breathing patients will usually manage to breathe through their ow n upper airway or the stoma. If the tracheostomy is >1 week old, the stoma is generally wel l established to allow early tube replacement if required. For patients dependent on assist ed ventilation, re-intubation by the oral route may be needed in the interim if dif \201 c ul- ties occur in replacing the tracheostomy tube. When caring for a tracheostomy patient, the following equipment should always remain with the patient: \200 longer term as they are thought to keep the stoma open and are easier to change. Cuffed tub es provide airway protection and facilitate IPPV. Disadvantages are risk of excessive cuff pressure, and dif \201 culty in swallowing and communication. High-volume low-pressure cuf fs reduce the incidence of cuff-related mucosal damage by providing a wider surface area of the trachea for the pressure to be dissipated. The cuff pressure should not exceed 25cm H2 O (18mm Hg) to reduce the risk of impaired mucosal perfusion, tissue necrosis and tracheal stenosis. Adjustable longer length \202 ange tubes are designed for patients whose trache a is deeper than usual below the skin and soft tissues in the neck, e.g. obese patients. Th e depth of the stoma should be considered at the outset, during the insertion procedure and by visualizing the tube posi- tion within the trachea at endoscopy via the glottis and thr ough the tube. Tracheostomy tubes with an inner tube may remain in place up to 30 days or m ore as the inner cannula can be cleaned and changed regularly. A fenestrated tube allows ai r \202 ow through the vocal cords when the tube is occluded or a speaking valve is attache d. A disadvantage is that the diameter of the inner lumen will be reduced by 1 \200\2232mm, increasing work of breathing and potential for aspiration of gastric contents. It is unsui table for patients dependent on positive pressure ventilation unless a non-fenestrated inne r cannula is used. There have been problems with surgical emphysema when the fenestrations lie within the stoma and air under positive pressure tracks up between the inner liner and the tube itself. Changing tracheostomy tubes Basic principles for changing a tracheostomy tube \200 Tracheostomy tubes without an inner cannula should be changed every 7 \200\22314 days, the frequency then decreasing once the patient is free of pulmonary secretions and has a well-f ormed clean stoma. A European Economic Community Directive (1993) states that tracheostomy tubes with an inner cannula can remain in place for a maximum of 30 days. The \201 rst ro utine tracheostomy tube change: \200 Tracheostomy tubes (same size as in situ and one size smaller) Tracheal dilators Suction un it, catheters and gloves Self-in \202 ating bag-valve mask device and tubing A 10ml syring e for cuff in \202 ation and de \202 ation Translaryngeal intubation equipment Portable o xygen \200 \200 \200 \200 \200 Should not be performed within 72h following a sur- gical tracheostomy and not before 3 \200\2235 (and ideally 7 \200\22310) days after a percutaneous tracheostomy to allow the st oma to become established. The decision to change the tube must be made by a medical practi tioner competent in the care of trache- ostomies. Must be carried out by a medical practiti oner with appropriate, advanced airway skills. Choice of tracheostomy tube There is a wide range of tubes commercially available: \200 \200 \200 \200 \200 \200 \200 Rigid and \202 exible Plain and cuffed (pro \201 le vs non-pro \201 le cuff) Fixed leng th vs longer length adjustable \202 ange Inner liner for ease of cleaning Fenestrations f or communication PVC/silver/silastic materials Flexible, metallic reinforced tubes for dist orted airway anatomy Contoured tip for ease of percutaneous insertion Thin walled to reduce external diameter Subsequent changes can be made by experienced personnel trained in tracheostomy tube change s (e.g. specialist tracheostomy nurse). \200 In practice, the frequency with which the tube needs to be changed will be affected by the individual patient \200\231s condition and the type of tube used. Elective changes are inhe rently safer than those done in a crisis. Soft and \202 exible tubes provide maximum patient comfort, minimizing any trauma to the trachea and associated structures. Rigid tubes are used more commonly in the 37 CHAPTER 1.16 Aftercare of the patient with a tracheostomy successful de-cannulation. An impaired conscious level also reduces the chance of success. There is a common ten- dency to leave tubes in too long whilst clinicians await the perfect time to de-cannulate, and time-consuming referrals to speech or physiotherapy are made. If left too long, it can stimulate mucus production and affects the mucociliary system. It sh ould be appreciated that an effective cough relies on build up of positive pressure within the trachea against a closed glottis and then sudden release to gener- ate a cough. This ca nnot be achieved with a large bore cannula open within the trachea. So you may be doing you r patient a disservice by leaving the tube in situ for too long. Following de-cannulation, most tracheostomy stomas are allowed to granulate without suturing. They achieve a func- ti onal seal within 2 \200\2233 days. These partially healed wounds can be quickly re-opened w ith artery forceps in the \201 rst few weeks after closure if necessary. Occasional patie nts will require ENT referral for tethered scars or a sinus. At longer term follow-up, clin icians should be aware of the rare signi \201 cant tracheal or laryngeal stenosis giving r ise to respiratory symptoms of stridor, persistent cough and voice changes. Such cases requ ire specialist ENT or thoracic referral. Initiation of oral intake \200 \200 \200 Con \201 rm that patient can tolerate cuff de \202 ation Sit patient up with head slightl y \202 exed and de \202 ate cuff Start with sips of water, moving on to thickened \202 uids and then a soft diet providing patient shows no signs of respiratory distress (coughi ng, de-saturation, increased tracheal secretions, etc.) In problematic cases, consider referral to speech and language therapy. Risk factors for swallowing problems in patients with a tracheostomy \200 \200 \200 Neurological injury, e.g. bulbar palsy Head and neck surgery Evidence of aspiration of ente ral feed or oral secretions on tracheal suctioning Increased secretion load, or persistent wet/weak voice, when cuff is de \202 ated Coughing and/or desaturation following oral inta ke Patient anxiety or distress during oral intake \200 De-cannulation De-cannulation should be considered when patients demonstrate a satisfactory respiratory drive, a good cough and the ability to protect their own airway. Patients who show no signs of tiring on cCPAP or a T-piece with low flow oxygen therapy are potential ca ndidates for de-cannulation. Coughing secretions up into the tracheos- tomy tube is a good sign, whereas generalized weakness and inability to hold the head up are negative predictor s of Further reading Paw H, Bodenham A. Percutaneous tracheostomy. Greenwich Medical, 2004. Standards for care of adult patients with temporary tracheostomies. Intensive Care Society 2007. www.ics.ac.uk. 38 J BALL Chest drain insertion Indications \200 Procedure Seldinger technique Though not obligatory, it is undoubtedly best practice to per form a thoracic ultrasound immediately prior to aspiration to de \201 ne the anatomy and a void visceral injury. When aspirating small or complex collections, continuous ultrasound g uidance is essential. Clean the area and apply sterile towels. Infiltrate a small volume of local anesthetic into the subcutaneous and intradermal spaces, avoiding the neuro- vascula r bundle which runs along the inferior border of the rib. Insert the needle, whilst aspirat ing using a syringe, until air/ \202 uid is freely withdrawn. Having entered the pleural space, disconnect the syringe and gently insert the J-wire through the needle. Be aware, th at the J-wire, despite its soft tip, can puncture and damage visceral organs, in particular consolidated lung. Withdraw the needle, leaving the wire in situ. Make a small stabbing in cision through the skin at the exit site of the wire. This is most easily performed by plac ing the \202 at surface of a no. 11 blade on the wire and sliding it into the skin. Inser t the dilator into the pleural cavity over the wire; be cautious not to insert this too far and angle the tract formed towards the desired location (apical for simple pneumothorax; p osterior-basal for \202 uid). Leave the dilator in place for a few moments, then remove, again leaving the wire in situ. Depending upon the drain design (straight, curved or pigtai l), ensure it is mounted on its stiffener (if required) and gently insert, over the wire, d irecting the tip as required. Withdraw the wire and stiffener then connect to a closed 3-wa y tap. Aspirate via the tap to ensure adequate placement and anchor with a holding suture. Connect to the appropriate drainage device, having \201 rst obtained any desired specimen s (see Chapter 1.18). Pad and stick to the skin using a small dress- ing, ensuring that the drain will not kink and that the 3-way tap is accessible and will not cause a pressure inj ury. One possible technique is to stick the drain in line with the ribs directed anteriorly . Treatment of a pneumothorax in a patient requiring positive pressure ventilation Treatment of a large pneumo/hydro/haemo thorax Following needle decompression of a tension pneumot- h orax Management of broncho-pleural \201 stula Management of empyema Management of localiz ed pneumothorax causing ventila- tory compromise (this usually requires CT guidance) \200 \200 \200 Equipment preparation Depending upon the size, site and anticipated nature of the pleural c ollection, select an appropriate drain. Smaller drains are preferable for most indications. The exceptions requiring larger drains with multiple (>3) holes are: \200 \200 \200 Bronchopleural \201 stulas with a large gas leak Haemothoraces with ongoing bleeding Visc ous/highly purulent empyemas This procedure should always be performed with strict adherence to aseptic precautions. Sug gested items: \200 \200 \200 2% chlorhexidine-based skin cleaning \202 uid and reservoir. Sterile gauze Local anesthet ic, syringe and needle. Consider adjunc- tive systemic analgesia and sedation. For Seldinge r technique: \200 Bedside ultrasound \200 Needle and syringe \200 J-wire \200 Scalp el \200 Dilator \200 Drain with stiffener \200 3-way tap For blunt dissection/thoraco stomy technique \200 \200 \200 Collection bag/underwater seal drainage bottle/Heimlic h valve Suture Appropriate dressing Scalpel Blunt dissection forceps (e.g. curved Robert \200\231s) Drain Blunt dissection/thoracostomy technique Clean the area and apply sterile towels. The site o f drain insertion should usually be in the so-called \200\230safe triangle \200\231. This is made up of the anterior border of latissimus dorsi, the lateral border of pectoralis maj or, a line superior to the horizontal level of the nipple, and an apex below the axilla. In filtrate a small volume of local anesthetic into the subcutaneous and intradermal spaces, a voiding the neuro- vascular bundle which runs along the inferior border of the rib. As an a lternative, consider performing an intercos- tal nerve block in the relevant space and the spaces above and below. Perform a diagnostic aspiration to ensure air/ \202 uid can be dr ained from the intended insertion site. Make a 2 \200\2233cm incision along the upper edge of the rib that makes the inferior border of the relevant rib space. Using forceps, bluntly dissect into the pleural cavity. Insert a \201 nger into the pleural cavity and perform a sweep. This acts as \200 Patient preparation Whenever practical, inform the patient regarding the pro- posed procedu re and gain their consent. Position the patient such that they are comfortable and the area in which the procedure is to be performed is easily accessible and, for fluid collections, is gravitationally dependent. This may be dif \201 cult in sedated and intubated patients on positive pressure ventilation. Sitting the patient in as near an upright posture as pos sible with unhindered access to the posterior and/or lateral chest walls is ideal. Ensure t hat whatever the position, the operator is in an ergonomic position with access to the equi pment. 39 CHAPTER 1.17 Chest drain insertion drain, except transiently, should be avoided. Clamping has no place in the management of pn eumothoraces. For small drains, consider \202 ushing 6 \200\22312 hourly with 5 \200\2231 0ml of 0.9% saline to assess and maintain patency. If connected to an underwater seal drain age bottle, the meniscus in the tube should transduce intrapleural pres- sure and swing wit h respiratory phase. If it does not, the drain is blocked, kinked or has become mislocated. Examine, \202 ush and re-image as necessary. a diagnostic examination, enhances the blunt dissection and can potentially break down locu lations, if present. Take hold of the drain tip with the forceps by placing them in through the distal side hole and out through the end hole. Prior to drain insertion consider disco nnecting the patient from any positive pressure ventilation to reduce the chance of intrapu lmonary lung placement. Gently insert the drain with the forceps and release. Try to positi on the drain apically for a pneumothorax and posterior-basally for \202 uid. Be cautious of intrapulmonary and mediastinal drain place- ment. To ensure adequate position and to obt ain any desired specimens, aspirate using a bladder-tipped syringe and/or connect to an und erwater sealed drainage bottle. Suture one end of the incision and place an anchoring sutur e around the drain. Avoid purse string sutures and use mono \201 lament suture material. P ad and stick to the skin using a small dressing, ensuring that the drain will not kink. One possible technique is to stick the drain in line with the ribs directed anteriorly. Removal Remove the drain as soon as it is no longer required or has failed. Close the drain site with a suture if required. If there continues to be a leak through the drain site, pl ace a stoma bag over it. If this fails to contain the situation, then either insert a new d rain or seek surgical advice. Complications \200 Bleeding from an intercostal vessel or a damaged viscous/organ. This is rare, but can be fa tal. Trauma to lung (including formation of bronchopleural fistula), heart, liver, spleen o r kidney. Again serious trauma is rare, but can be fatal. Infection: from super \201 cial drain site infection to empyema and lung abcess. Management Following insertion, obtain a CXR to assess the position. If functionally inadeq uate, regardless of radiological posi- tion, manipulate the drain accordingly or remove and , if necessary, re-insert. In dif \201 cult circumstances, seek radio- logical advice and consider CT guidance or thoracic surgi- cal assistance. Draining \202 uid off at too high a rate can result in re-expansion pulmonary oedema. This is rare, especially in patients r eceiving positive pressure ventilation. The risk can be minimized by limiting drainage to a maximum of 1500ml/h by clamping the drain. In all other instances, clamping of the Further reading Bouhemad B, Zhang M, Lu Q, et al. Clinical review: bedside lung ultrasound in critical care practice. Crit Care 2007; 11: 205. Laws D, Neville E, Duffy J, et al. BTS guidelines for the insertion of a chest drain. Thorax 2003; B Suppl 2: ii53 \200\2239. 40 J BALL Pleural aspiration Insert the needle/cannula, whilst aspirating using a syringe, until air/fluid is freely wit hdrawn. Having entered the pleural space, if there is a signi \201 cant volume of air/ \202 uid to be aspirated, attach a 3-way tap on a short extension to facilitate syringe cha nge over. If no \202 uid/air is aspirated, remove the needle/cannula and re-image with ul trasound. If necessary, reposition the patient. For a simple pneumothorax, aspirate as much air as possi- ble, making note of the volume. If, having drained 1000ml, air is still free ly aspiratable, consider inserting a pleural drain. If in doubt, re-image with X-ray or ult rasound. For a pleural effusion, aspirate suf \201 cient \202 uid for all diag- nostic t ests. Continue to aspirate further \202 uid if there is a significant residual volume. Me asure the total volume removed and be conscious of the possibility of re-expan- sion pulmon ary oedema. Once completed, remove the needle/cannula and cover the puncture site with a si mple dressing if required. If \202 uid starts to leak through the puncture site, cover wi th a small stoma bag or consider inserting a drain. Pleural aspiration or thoracocentesis is the removal of air or \202 uid from the pleural space (see also Chapter 1.17). Indications \200 \200 \200 Diagnosis of the nature of a pleural effusion Treatment of a simple pneumothorax Treatment of pleural effusion of suf \201 cient size to impair or compromise respiratory mechanics T reatment of an empyema Equipment preparation Depending upon the size, site and anticipated nature of the pleural c ollection, select an appropriately sized needle or cannula. This procedure should always be performed with strict adherence to aseptic precautions. Suggested items: \200 \200 \200 \200 \200 Bedside ultrasound 2% chlorhexidine-based skin cleaning \202 uid and reservoir. Sterile g auze Local anesthetic, syringe and needle. Chosen needle/cannula, t3-way tap on a short ext ension, an appropriately sized syringe for sampling/aspiration (20 \200\22360ml). Sterile s ample pots, blood gas syringe, glucose testing strip or blood glucose ( \202 uoride) sampl e bottle, blood culture bottles (aerobic and anaerobic), blood chemis- try/enzyme assay sam ple bottle Small dressing Specimens For microbiology, send raw \202 uid for microscopy, culture and sensitivities. If suspicious, also request staining and culture for mycobacteria. To increase the sensitiv ity of bacterial culture, inoculate a set of blood culture bottles with 10ml of \202 uid per bottle. Unless the \202 uid is frankly purulent, take a specimen in a blood gas syrin ge and put it through a blood gas analyzer to measure the pH. A pH <7.20 is consistent with an empyema and probably the most sensitive test. The two other assays consistent with this diagnosis is a \202 uid glucose of <3.35mmol/l and/or a lactate dehydrogenase level >3 t imes the upper limit of normal for serum. Determination of the fluid total protein to estab lish whether the effusion is a transudate or exudate is not of any great value and is unrel iable in diagnosing empyema. Patient preparation Whenever practical, inform the patient regarding the proposed procedure and gain their consent. Position the patient such that they are comfortable and the area i n which the procedure is to be performed is easily accessible and, for fluid collections, i s gravitationally dependent. This may be dif \201 cult in sedated and intubated patients o n positive pressure ventilation. Sitting the patient in as near an upright posture as possi ble with unhindered access to the posterior and/or lateral chest walls is ideal. Ensure tha t whatever the position, the operator is in an ergonomic position with access to the equipm ent. Complications and their management The most common complication of pleural aspiration is a small pneumothorax. This requires no action other than vigilance for increasing size, which is rare unless the lung has been punctured. If this has occurred, it is usually obvi- ous, as air is unexpectedly aspirated during the procedure. The risk of an enlarging.significan t pneumothorax is increased if the patient is on positive pressure ventilation. Under these circumstances, watch for an evolving tension pneumothorax and be prepared for immediate de com- pression and chest drain insertion. The second most common complication is damage to t he intercostal neurovascul;ar bundle. To avoid this, use the superior border of the rib as the landmark for the punc- ture site and maintain an insertion angle that minimizes the ris k of damage to the bundle associated with the rib above. Be aware that damage to the interc ostal artery can result in a signi \201 cant haemothorax and require surgical ligation.