Practical procedures and patient investigation

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8 Practical procedures and patient investigation

R.W. Parks

Chapter contents

Introduction

General precautions

Aseptic technique

Local anaesthesia

Suturing

Airway procedures

Thoracic procedures

Abdominal procedures

Vascular procedures

Urinary procedures

Central nervous system procedures

Excision of lumps and swellings

Imaging

Introduction

Every practical procedure performed on a conscious patient should be preceded by an explanation, which should include the reasons for the procedure and what it will entail. Appropriate reassurance should always be given. Many patients find comfort in continuing reassurance throughout the procedure, and most are helped by a description of sensations they are likely to experience before these occur. Where appropriate, informed written consent should be obtained. A record that the procedure was performed should be made in the case notes.

General precautions

It is important to be aware of the risk of infection or trauma to patient, operator and assistant during any practical procedure. These risks are minimized by following a few simple rules:

• Needles should not be resheathed and all disposable sharp instruments discarded by the operator should be placed in an appropriate container to minimize the risk of needle-stick injury

• Drapes and other soiled equipment should be placed in appropriate containers

• Gloves and gown should only be removed after all used instruments and disposable equipment have been placed in appropriate containers.

Aseptic technique

Transmission of infection is an ever-present problem, and the risk of spread should be minimized. As a minimum precaution, the skin should be cleansed with an antiseptic solution before all procedures, and sterile instruments used. For some procedures, such as central venous catheterization, bladder catheterization, insertion of chest drains and lumbar puncture, a full aseptic technique must be employed. The steps required are outlined in Table 8.1.

Table 8.1 Aseptic technique

• An assistant is desirable to open non-sterile packs and ‘drop’ required instruments or solutions on to the sterile field

• Hand-washing for aseptic techniques (‘scrubbing up’) should last a full 3 minutes. The hands and forearms are wetted under a running tap and thoroughly washed with an antiseptic solution such as povidone-iodine (Betadine) or chlorhexidine (Hibiscrub)

• A sterile brush is then used to scrub the hands: in particular, the ulnar border, the interdigital clefts and the nails

• After the wash is completed, the hands are rinsed and held hands up/elbows down, so that water from the hands runs from the elbows into the sink

• The hands are dried on a sterile towel and the operator puts on a sterile gown and gloves. Thereafter, the operator must not touch anything other than sterile equipment or instruments

• The operative field is now cleansed with an antiseptic solution such as povidone-iodine or chlorhexidine, using sterile instruments and swabs. The area prepared should be much greater than the anticipated operative field, and cleansing should start from the centre and work outwards

• The operative field is then encircled with sterile drapes, which are secured so as to leave the operative field at the centre and provide the operator with as wide a sterile surrounding as possible

Local anaesthesia

Local anaesthetic agents inhibit membrane depolarization and hence block the transmission of nerve impulses. They may be used topically, i.e. painted or sprayed on mucous membranes and wound surfaces, so that they are absorbed locally to produce analgesia. Areas suitable for topical analgesia include the urethra, eye, nose, throat and bronchial tree. Local anaesthesia may also be administered by local infiltration, and this is used widely for minor surgical procedures. Local anaesthetic drugs are potentially toxic and care must be taken to avoid inadvertent intravascular injection. The first sign of toxicity is often numbness or tingling of the tongue or around the mouth, followed by lightheadedness and tinnitus. At higher blood levels, there is loss of consciousness, convulsions and apnoea. Cardiovascular collapse eventually occurs as a result of myocardial depression, vasodilatation and hypoxia. In general, efficacy is related to correct placement and toxicity to total dose. Where there is doubt about placement or a wide area of infiltration is anticipated, it is safer to calculate the maximum recommended dose and dilute it to the desired volume with 0.9% saline.

Lidocaine is the most widely used local anaesthetic agent and is available in 0.5–2% solutions. The maximum recommended dose is 3 mg/kg. Lidocaine is a short-acting anaesthetic (lasting up to 2 hours), whereas bupivacaine is longer-acting (up to 8 hours). A mixture of the two can be administered.

Solutions of local anaesthetic mixed with a 1:200 000 concentration of adrenaline (epinephrine) are also available. Adrenaline acts as a vasoconstrictor. It minimizes bleeding and reduces redistribution of the anaesthetic agent, thereby increasing its efficacy and duration of action. Local anaesthetic agents with adrenaline should not be used in anatomical areas supplied by an end-artery, such as the digits, because of the risk of vasoconstriction, ischaemia and gangrene.

Suturing

The purpose of suturing is to approximate tissue in such a manner as to allow optimum primary healing to take place or to ligate bleeding vessels to arrest haemorrhage. Needles can be straight or curved. Straight needles are usually hand-held whereas curved needles are designed for use with a needle holder. The thread is ‘swaged’ inside the needle, which can be cutting or round-bodied. The latter push tissue aside and can be used to reduce the risk of needle-stick injuries e.g. for closing the linea alba in abdominal wound closure, or for bowel/vascular anastomosis. Cutting needles are more commonly used for skin closure.

Suture materials

Non-absorbable sutures

Non-absorbable sutures may be classified into three groups:

1. Natural braided sutures (e.g. silk, linen) have good handling qualities and knot easily and securely. Their disadvantage is increased tissue reaction and suture line sepsis, caused by the capillary action of the braided material drawing micro-organisms into the suture track. Such materials also lose tensile strength quickly with time, or when wet.

2. Synthetic braided materials (e.g. Nurolon, Ethibond, Mersilene) cause less tissue reaction than natural materials. They have good handling qualities and knot easily and securely.

3. Synthetic monofilament materials (e.g. nylon, polypropylene) have less drag through the tissues and cause little tissue reaction. They are free from the capillary effect of braided sutures and cause less suture track sepsis. However, they handle less well because of increased ‘memory’ (i.e. they retain the configuration in which they were packaged). Knots in monofilament sutures are less secure than those in braided or natural sutures, requiring multiple throws on each one.

Absorbable sutures

Absorbable sutures are generally made from synthetic materials. They cause relatively little tissue reaction, retain their tensile strength and are absorbed slowly. They can be multifilament, such as Dexon (polyglycolic acid) and Vicryl (polyglycolic plus polylactic acid), or monofilament, such as Maxon (polyglyconate) and PDS (polydioxonone). These synthetic sutures are commonly used for intra-abdominal procedures and subcuticular wound closure. Interrupted sutures with each knot buried are used for small wounds, whereas in longer wounds a continuous subcuticular suture is employed.

Suturing the skin

Skin wounds are sutured under as near-sterile conditions as possible, using a strict aseptic technique. A few basic principles underlie good wound care:

• Tissue should be handled gently. The wound should not be rubbed with swabs. Blood in a wound is removed by pressing a swab on to it

• Haemostasis should be meticulous to prevent wound haematoma

• All foreign material and devitalized tissues should be removed. Where this is prevented by heavy contamination, delayed primary suture or secondary suture should be considered

• Potential spaces (dead space) in the wound should be closed using absorbable suture material such as Vicryl. Where this is not possible, a suction drain is led from the potential space before more superficial layers are closed

• The tension on knots is critical. If they are tied too tightly, the suture line may become ischaemic, leading to delayed healing or non-healing and an increased risk of wound infection. Equally, insufficient tension on the suture may result in failure to appose the wound edges or inadequate haemostasis.

Cutting needles are used to suture skin. Non-absorbable sutures are generally preferred, but require subsequent removal. Interrupted sutures have the advantage over a continuous suture in that the removal of one or two appropriately sited stitches may allow adequate drainage if the wound becomes infected. The sutures should be placed equidistant from one another, taking equal ‘bites’ on either side of the wound. A sufficient number should be inserted to maintain apposition without the skin edges gaping. The size of bite is determined by the amount of subcutaneous fat and by whether or not the fat has been separately sutured. For abdominal wounds, 5 mm bites are taken on either side of the wound, whereas on the face a 1–2 mm bite is preferred. The wound edge is picked up with toothed dissecting forceps, then the needle is introduced through the skin at an angle as close to vertical as possible and brought out on the other side at a similar angle.

Similar principles apply when using a continuous suture. A subcuticular continuous suture is preferred by some surgeons and avoids the small pinpoint scars at the site of entry and exit of interrupted sutures, or the ugly cross-hatching that results if sutures are tied too tightly or left in too long. Table 8.2 gives the suggested times for removal of sutures. Cosmetic results as good as those achieved by subcuticular suturing can be obtained by removing sutures in half the times listed in Table 8.2 and by replacing them with adhesive strips (e.g. Steristrip). Skin stapling is commonly used for closure of wounds at any site, as it can be undertaken rapidly. The staples are supplied in disposable cartridges for single patient use and are easily removed.

Table 8.2 Times recommended for removal of sutures

• Face and neck

4 days

• Scalp

7 days

• Abdomen and chest

7–10 days

• Limbs

7 days

• Feet

10–14 days

Airway procedures

Maintaining the airway

The ability to maintain the airway is a basic skill that every doctor, nurse, paramedic and indeed member of the general public should have. Its simplicity belies its importance, but it is a life-saving skill, which must be learnt through practice.

In the unconscious patient, muscles that normally maintain a clear airway become lax. The tongue and soft tissue fall backwards, particularly in the supine patient, occluding the airway. Maintaining a clear airway allows the patient to breathe or allows the lungs to be ventilated.

Procedure

The simplest manoeuvre is to place the patient on their side with the neck extended in the so-called ‘recovery position’. This allows the tongue and soft tissues to fall clear of the larynx and provide a patent airway. The mouth and pharynx should be checked and cleared of debris, such as dentures, vomit or food.

When the patient has to be kept supine, the neck should be extended. The mouth is opened slightly and the mandible pulled firmly forward by pressure applied behind both angles of the jaw. The mandible is held in this position by closing the mouth and using the teeth as a splint. Forward pressure is maintained behind the angles of the jaw (jaw-thrust manoeuvre) or submentally (chin-lift manoeuvre), avoiding pressure on the soft tissues (Fig. 8.1). In some cases, particularly in edentulous patients, an oropharyngeal airway helps to maintain a patent airway.

image

Fig. 8.1 Maintaining the airway.

A The jaw-thrust manoeuvre. B The chin-lift manoeuvre.

Ventilation by mask

The lungs may be ventilated by mask and bag, using one of two systems. The first is a rebreathing bag with an adjustable valve and fresh gas supply (which should be present in each anaesthetic room, intensive therapy unit and resuscitation room). The second and more widespread is the self-reinflating type of bag, such as the ‘Ambu’ or ‘Laerdal’ bags, which do not rely on a gas supply but to which supplemental oxygen can be added. For the inexperienced, this technique is best performed with the help of an assistant.

Procedure

The airway is held patent with the patient supine, as described above. A mask is applied to the face and held in position using the thumb and index fingers of both hands. The little fingers of each hand are placed behind the angles of the jaw and used to lift the mandible forward. The ring and middle fingers are placed on the mandible to help maintain this position. The assistant squeezes the bag to ventilate the lungs. The adequacy of ventilation is assessed by observing appropriate chest movement.

With more experience, it is possible to maintain a patent airway and hold the mask on with one hand, and squeeze the bag with the other.

The laryngeal mask airway

This airway device is designed to be inserted into the pharynx, and has a cuff that, when inflated, forms a cup around the larynx. It is not a replacement for endotracheal intubation and does not protect the airway from aspiration. It does, however, provide a patent airway when positioned correctly, and allows effective ventilation of the lungs. As with other procedures, insertion should be learned under supervision.

Procedure

For men a size 4 is suitable, and for women a size 3, with smaller sizes being available for children. The cuff should be deflated and lubricated with gel. The patient’s head is maintained in an extended position using the left hand, and the airway is held in the right hand and introduced into the mouth (Fig. 8.2). The airway is passed backwards over the tongue until resistance is felt. It should then be at the level of the larynx. The cuff is inflated and the airway should be seen to rise slightly out of the mouth. Position is confirmed by the ability to ventilate the lungs.

image

Fig. 8.2 Insertion of a laryngeal mask airway.

A Gentle insertion of airway with head in extended position. B Advancement of airway.

Endotracheal intubation

Endotracheal intubation can be life-saving; it can maintain a patent airway, facilitate oxygenation and prevent aspiration. Every opportunity should be taken to acquire this skill in the elective situation in the anaesthetic room.

Procedure

The patient’s neck is flexed and the head extended at the atlanto-occipital joint. Retaining a pillow under the head but leaving a space free from beneath the shoulders will usually help to attain this position. Failure to position the patient correctly is one of the most common causes of difficulty in intubation.

The laryngoscope is held in the left hand; its blade is inserted into the right side of the patient’s mouth and passed backwards along the side of the tongue into the oropharynx. The blade is designed to push the tongue over to the left side of the mouth. Care is taken to avoid damage to the lips and teeth. The laryngoscope is pulled upwards and forwards, not used as a lever, to lift the tongue and jaw and reveal the epiglottis (Fig. 8.3). The blade is then advanced to the base of the epiglottis and the laryngoscope pulled further upwards and forwards to reveal the vocal cords.

image

Fig. 8.3 Oral endotracheal intubation.

For men, a 9 mm cuffed tube is usually appropriate, and for women an 8 mm tube is generally used. For children, a rough rule of thumb to gauge tube size is age divided by 4, + 4.5 mm. Normally, an uncuffed tube is used in children.

The endotracheal tube is passed through the vocal cords into the trachea and advanced until its cuff is about 1 cm through. Many endotracheal tubes have a mark to indicate this position. The laryngoscope blade is then withdrawn and the cuff inflated to provide an airtight seal in the trachea.

The most serious complication of endotracheal intubation is failure to recognize misplacement of the tube, particularly in the oesophagus or, to a lesser degree, in the right main bronchus. Misplacement is best avoided by direct visualization of passage of the tube between the vocal cords, inspection of the chest wall for equal movement of both sides of the chest, and auscultation for breath sounds bilaterally in the mid-axillary line. Absence of breath sounds or the presence of only quiet ones in the epigastrium is a further reassuring sign. If there is any doubt about the position of the tube, it should be removed and ventilation instituted by mask.

Surgical airway

Inability to intubate the trachea is an indication for creating a surgical airway. In the emergency situation, such as in patients with severe facial trauma or pharyngeal oedema secondary to burns, the insertion of a large-calibre plastic cannula through the cricothyroid membrane (needle cricothyroidotomy) below the level of the obstruction can be life-saving. Intermittent jet insufflation of oxygen at 15 litres/min (1 sec inspiration and 4 secs to allow expiration) can provide oxygenation for a limited period (30–45 minutes) until a more definitive procedure can be undertaken.

Surgical cricothyroidotomy is performed by making an incision that extends through the cricothyroid membrane and inserting a tracheostomy tube.

In children, care must be taken to avoid damage to the cricoid cartilage, which is the only circumferential support to the upper trachea. Surgical cricothyroidotomy is therefore not recommended for children under 12 years of age.

Procedure

It is important to check all equipment and connections before starting. With the patient in the supine position and the neck in a neutral position, the thyroid cartilage (Adam’s apple) and cricoid cartilage are palpated. The cricothyroid membrane lies between the lower border of the thyroid cartilage and the upper border of the cricoid cartilage. The skin is cleansed with antiseptic solution and local anaesthetic infiltrated into the skin, if the patient is conscious. The thyroid cartilage is stabilized with the left hand and a small transverse skin incision made over the cricothyroid membrane. The blade of the scalpel is inserted through the membrane and then rotated through 90° to open the airway. An artery clip or tracheal spreader may be inserted to enlarge the opening enough to admit a cuffed endotracheal or tracheostomy tube (Fig. 8.4). The central trocar of the tube is removed and the tube connected to a bag-valve or ventilator circuit. The cuff is then inflated and air entry to each side of the chest is checked. The tube is secured to prevent dislodgement.

image image image

Fig. 8.4 Surgical cricothyroidotomy.

A Palpation of thyroid cartilage. B Incision through cricothyroid membrane. C Insertion of tracheostomy tube.

Formal open tracheostomy may be performed as an emergency procedure, but is more commonly undertaken in critically ill patients requiring long-term ventilation. It is a procedure for an experienced clinician and involves making an inverted U-shaped opening through the second, third and fourth tracheal rings.

Changing a tracheostomy tube

It is common practice to change a tracheostomy tube every 7 days. Suction must be available.

Procedure

If a cuffed tube is to be inserted, the integrity of the cuff is checked and it is then fully deflated. Lubricant gel is applied to both the cuff and tube. The patient is placed semi-recumbent with the neck extended. If replacement is likely to be difficult, a suction catheter inserted into the old tracheostomy tube can be used as an introducer for the new tube.

The cuff of the old tube is deflated. Secretions often collect above the cuff and enter the trachea when it is deflated, causing the patient to cough; both patient and operator should be alert to this. Because the tube is curved, it should be removed with an ‘arc-like’ movement. The site is then cleansed and any secretions are removed. In the spontaneously breathing stable patient, there is no need for undue haste. The new tube is inserted with a similar movement to that employed for removal, and its cuff inflated.

Any signs of respiratory distress should raise suspicion of the possibility of misplacement or occlusion of the tube. The tube and trachea are immediately checked for patency by passing a suction catheter through the tube. If the catheter passes easily into the respiratory tract, usually signified by the patient coughing as the catheter touches the carina, other causes for respiratory distress should be sought.

When the tracheostomy is no longer needed, an airtight dressing is applied over the site after removing the tube. There is no need for formal surgical closure at this stage, as in most instances the wound will close and heal spontaneously. For the first few days, patients should be encouraged to press firmly on the dressing when they wish to cough, so as to avoid air leakage through the tracheostomy site.

Thoracic procedures

Intercostal tube drainage

Intercostal intubation is used to drain a large pneumothorax, haemothorax or pleural effusion. To drain a pneumothorax, a size 14–16 Fr catheter is inserted, using a lateral approach in the mid-axillary line of the sixth intercostal space. Drainage of an effusion or haemothorax requires a larger drain (20–26 Fr), which should be inserted in the seventh, eighth or ninth intercostal space in the posterior axillary line. A slightly higher insertion in the mid-axillary line may be technically easier in supine, acutely ill patients.

Procedure

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