Ghai Essential Pediatrics8th

10-20 ml/kg, it increases the level at coagulation factors by 20% immediately after infusion.

Cryoprecipitate

Cryoprecipitate is the precipitate formed when FFP is thawed at 4°C. It is then refrozen within 1 hr in 10-15 ml of the donor plasma and stored at -18°C or less fora period up to one year. This unit contains 80-100 units of factor VIII, 100-250 mg of fibrinogen, 40--60 mg of fibronectin, 40-70% of vWF and 30% of factor XIII.

Indications. These include hemophilia, von Willebrand diseaseand congenital deficiencies of fibrinogen or factor

XIII.

Pediatric Critical Care -

Dose. ABO compatible units should be used and compati­ bility testing orconsiderationof Rh group is not necessary. One unit is administered for every 5-10 kg of recipient weight, rapidly over 1-2 hr.

Risks from Transfusion

Before prescribing blood or blood products, it is essential toweighthebenefitsagainsttherisksoftransfusion.Tables 27.17 and 27.18 summarize adverse effects of transfusion of blood or blood products. Specific risks include: (i) risk ofserioushemolytictransfusion reaction; (ii) transmission of infectious agents including HIV, HBV, HCV, syphilis, malaria, CMV; and (iii) contamination of blood products with bacteria due to inappropriatecollection or storage.

Time Limit for Infusion

There is a risk of bacterial proliferation or loss of function in blood products once they have been removed from the storage conditions.

Whole blood, packed red cells. Transfusion should be started within 30 min of removing the pack from storage tempe­ rature (+2 to +6°C). The transfusion should be completed within 4 hr of start if the hospital temperature is between 22°C and 25°C. In case of high ambient temperature, faster infusion is preferred.

Platelets. These should be infused as soon as they have been received and infusion should be completed in 30 min.

FFP. In adults, one unit of FFP (200-300 ml) is administered over 30-60 min, starting within 30 min of receiving. In children, the rate of infusion depends on the clinical condition.

The blood products should be infused through a new, sterile blood administration set containing an integral 170-200 µm filter which is changedevery 12 hr if multiple transfusions are needed. For platelet transfusions, a fresh set primed with saline should be used.

Suggested Reading

Lacroix J, Luban NLC, Wong ECC. Blood products in the PICU. In: Nichols DG, ed. Roger's Textbook of Pediatric Intensive Care. 4th edn. Lippincott Williams & Wilkins, Philadelphia; 2008:584-99

Medical procedures involved in care of children include diagnosticproceduresandtherapeuticinterventions,some of which may be critical or life-saving. It is important to observe universal sterile precautions during any medical procedure and dispose waste articles appropriately. This chapter shall cover indications, key steps of the perfor­ mance and potential complications for these procedures.

Obtaining Blood Specimens

Sampling of biological specimens is the most common procedure in clinical practice.

Indication Blood sampling may be required for tests to diagnose a variety of conditions: Blood culture is essential to detectbacteremiain anewbornwithsuspected sepsisor an older febrile child withtoxic appearance. Two or three sets of samples should be drawn from separate venipunc­ ture sites in patients with suspected endocarditis or fever of unknown origin. Simultaneous sampling of peripheral blood and from catheter lumen is useful in patients with

suspected catheter related bloodstream infections. Procedure Disinfectants used for preventing culture

contamination with skin flora include povidone-iodine, 70%isopropylethylalcoholorchlorhexidine, and areoften usedincombination.The veinis palpated and a tourniquet applied if the vein is not palpated. The site for venipunc­ ture is cleaned with an alcohol wipe and left to dry for a minute. Povidone-iodine is applied in concentric circles outwards, allowed to dry for at least 60 seconds. The two steps are repeated to minimize contamination. The vein is punctured at an acute angle to the skin with the bleb of the needle pointing upwards and directed cephalad. The appropriate volume for blood culture depends on the broth system used; most require drawing of 3-10 ml of blood. The likelihood and degree of bacteremia is more in children than adults, and therefore, a smaller volume may be sufficient. Some tube-based pediatric Bactec broths require only 0.5 ml of blood.

Complications Commoncomplicationswithphlebotomy includelocalpain,swellingandextravasationofblood.Poor skin preparation is a common cause of blood culture contamination. Bacteria from thephlebotomist's hands or respiratory droplets may also contaminate blood culture.

Removal of an Aspirated Foreign Body

Foreign body airway obstruction is a common medical emergency, especially in children younger than 5-yr-old. Most events are witnessedand may be caused by choking on toy parts, seeds, nuts, grapes, pebbles or buttons. The usualpresentationis with sudden onset of cough, gagging or strider with or without respiratory distress. A foreign body obstructing the upper airway completely can cause hypoxemia, cyanosis and secondary cardiac arrest. If the child can speak, breathe or cough, partial obstruction is likely. While this indicates that there is no immediate threat to life, the foreign body may get dislodged and obstruct the airway totally.

Indication Patients with either complete airway obstruc­ tion or partial airway obstruction with poor air exchange require immediate relief.

Procedure A choking infant younger than 1 yr is placed face downovertherescuer'sarm,withtheheadpositioned below the trunk. Five measured back blows are delivered rapidlybetween theinfant's scapulae using the heel of the hand (Fig. 28.1). If obstructionpersists, the infant is rolled over and five rapid chest compressions are performed, similarto cardiopulmonary resuscitation.The sequenceof back blows and chest compressions is repeated until the obstruction is relieved. Abdominal thrusts (Heimlich maneuver) may be performed in children older than 1 yr (Fig. 28.2).However, specialcareshould be taken to avoid injurytoabdominalorgans,particularlyinyoungchildren. When initial interventions fail, a jaw thrust is performed, since this may partially relieve the obstruction. If the

Fig. 28.1: Back blows in a choking infant

Fig. 28.2: Heimlich maneuver in a child

foreign body can be visualized, it should be removed manually using Magill or other large forceps.

In the unconscious apneic child, a tongue-jaw lift can be performedbygraspingbothtongueandlowerjawbetween the thumb and finger and lifting. Blind finger-sweeps are avoided in infants and young children because they may push the foreign body further back into the airway, worseningtheobstruction. Childrenpresentingwithsigns and symptoms of foreign body aspiration beyond the oropharynxintothetrachea or bronchus require broncho­ scopy by experienced personnel.

Complications Chest compressions may cause rib and cardiac damage in infants, but are rare if performed by experienced personnel. Uncommon complications of the Heimlich maneuver, if performed incorrectly, include pneumomediastinum, rupture of spleen or stomach and injury to the aorta.

Nasogastric Tube Insertion

Indications Nasogastric intubation is usually performed for: (i)administrationofmedicationsornutrientsinuncon­ sciousoranorexicchildren;(ii)gastrointestinaldecompres­ sion in case of intestinal obstruction or trauma; and (iii) gastric lavage in a patient with upper gastrointestinal bleeding or toxin ingestion.

Procedure The largest size tube that does not cause undue discomfort to the child is chosen. Typically, an 8 Fr tube is used inneonates,10 Fr fora 1-yr-oldandincreas­ ing sizes in childhood up to 14-16 Fr tubes in teenagers. The length of tubing to be passed is estimated by adding 8-10 cm to thedistancebetweenthenostrilsto thexiphoid process. Thechildis prepared byexplainingthe procedure as fully as possible; sedation is rarely needed.

Infants and obtunded children are placed supine with theheadturnedtooneside. Thecurvedtubeisstraightened and its patency checked with a syringe. Application of a lubricant facilitates atraumatic nasal passage. The tube is grasped 5-6 cm from the distal end and advanced poste­ riorly along the floor of the nose. It is inserted with its natural curve pointing downward in order to go past the bend of the posterior pharynx easily. The procedure is discontinued temporarily if the child coughs or gags or if the tubeemerges fromthe mouth. Whenthe tube ispassed successfullytothemeasuredlength,itspositionischecked. Usinga5mlsyringefilledwithairattachedtotheproximal end, theplungerisdepressedrapidlywhileoneauscultates for gurgling over the stomach. The tube is taped securely to the nose.

Complications The procedure may be associated with tracheal intubation, nasal or pharyngeal trauma, or vomiting.

Venous Catheterization

Peripheral Percutaneous Venous Catheterization

Small caliber plastic catheters and small over-the-needle catheters (22-24 gauge) areavailabletocannulateeven the smallveins ofthehand, foot orscalp of neonates. Selection of catheter size and peripheral venous site are important issues. Inolderchildren,veins in thebackofthehandsand forearms are commonly used. For a patient in shock, the widest and shortest catheter is optimal, because longer, narrower catheters result in more resistance to flow. The greater saphenous vein, median cubital vein and external jugularvein arethreesitesthatareoftenusedbecause they are relatively large and consistent in location.

Before the vein is cannulated, the operator should wash his or her hands well and use universal precautions. The extremity should be adequately immobilized and the site cleansedwithalcoholandpovidone-iodineandallowedto dry. Atourniquet isappliedproximallyinordertoengorge and distend the vein. The skin can be stretched taut with the operator's nondominant hand in order to immobilize

thevein. Theoperator shouldpuncturethe skinat a15-30° angle, 5-10 mmdistal to the expected entrancesite intothe vein. The subsequent puncture of the vein by the needle is suggestedbybloodreturnintothecatheterhub.Whenthis isnoted,thecatheterisadvancedafewmillimeters toensure that the catheter tip, as well as the needle, is in the lumen of the vein. The catheter is then advanced over the needle into thevein, and the needle is removed. The tourniquet is released and saline is flushed intravenously to ensure patencyofthecatheterandvein.Itisimportanttoadequately secure and protect the catheter after successfulcannulation.

The most common complication of peripheral venous cannulation is catheter displacement and infiltration of tissues with the infusing fluid.

Scalp Vein Catheterization

Indication To achieve intravenous access for delivering fluids and/or medications in infants, when peripheral extremity veins are unavailable.

Technique The infant below 1-yr-old has several easily accessible scalp veins. These include the frontal, supra­ orbital,posteriorfacial, superficial temporal and posterior auricular veins and their tributaries. The patient is res­ trainedinasupinepositionwhileanassistantstabilizesthe infant's head. Thescalp is shaved in an area large enough to expose the desired veins and to allow adequate taping oftheinfusionneedle.Inthisarea, aveinisselectedthathas a straight segment at least as long as the part of the needle that is to be inserted.

The skinispreparedbycleansing with povidone-iodine solutionfollowed byalcohol. A butterfly scalp veinneedle is graspedbythe plastic tabs or 'wings' andinserted in the directionofbloodflow,piercingtheskinapproximately0.5 cm proximal to the actual site where entry into the vein is anticipated.Whileapplyingmildtractionontheskinofthe scalp, the needle is slowly advanced through the skin toward the vein. Blood will enter the clear plastic tubing when successful venipuncture has occurred. Using a syringe filled with normal saline flush solution, 0.5 ml of salineisinjectedslowly.Iftheneedleis satisfactorilyinser­ tedintothe lumenof thevein, the solution will floweasily. Appearance of a skin wheal indicates that the vein has not beensatisfactorilycannulatedandanotherattemptmustbe made. After successful catheterization, the scalp vein needle is taped carefully.

Common Medical Procedures -

Complications Inadvertentarterial puncture;ecchymoses and hematoma of the scalp may occur.

Central Venous Cannulation

Indications Usualindicationsinclude: (i)inabilitytoestab­ lish venous access in the peripheral circulation; (ii) access fordrugsandfluidsthatrequirecentraladministration(e.g. vasopressors, hyperalimentation fluids, contrast medications); (iii)tomonitorcentral venous pressure; and (iv) as an access for performing hemodialysis, plasma­ pheresis or continuous renal replacement therapies.

Procedure Principlescommontoallcentralvenouscathe­ terprocedures,regardlessofsite,include: (i)strictattention to asepsis; (ii) use of the Seldinger technique (placement overaguidewireminimizestraumaandhematomaforma­ tion and enhances successful cannulation); (iii) adequate sedation to minimizemovements; (iv) attention to appro­ priatelocationofcathetertip, avoiding high-risksitessuch as ventricles and left atrium, verifying tip position with a radiograph; (v) avoiding placement in presence of a bleedingdiathesis;and (vi) continuousmonitoringofvital signs and oxygen saturation.

Sites The site of access depends on the indication (Table 28.1).

i.External jugular vein. The external jugular vein can be identified easily. There is less risk of pneumothorax. Complications are minimal because of the superficial position of the vein and the ability to compress the vein to prevent hemorrhage.

ii.Internal jugular vein. Internal jugular vein cannulation

provides an excellent approach to the central circula­

tion with a high success rate and minimal compli­ I cations. Carotid artery puncture and pneumothorax

are the most common complications. With left-sided cannulation thereis potential forinjury to the thoracic duct and there is a higher risk for pneumothorax because the apex of the left lung is higher than on the right.

iii.Subclavian vein cannulation. Thisveinis thepreferred site inpatientswithlongtermcatheterrequirementsbecause of its relatively high level of patient comfort and ease of

cathetermaintenance.Inpatientswith hypovolemia, the subclavian vein does not collapse as readily as other

majorvessels because of fibrous attachments to directly belowtheclavicle. Majorcomplicationofsubclavianvein cannulation are pneumothorax, subclavian artery puncture, or occasionally, hemothorax.

iv. Femoral vein cannulation. Femoral veincannulation isthe most common site for central vein cannulation as it is easily accessible, avoids possiblepleura andlung punc­ ture, does not require Trendelenburg position and seriouscomplicationsarerare.Alloftl1esereasonsmake itpopularinthepediatricpatient,especiallyinoneneed­ ingairwaymanagementor cardiopulmonary resuscita­ tion.Attheinguinalligamenttheveinlies inthefemoral sheathjustbelowtheskinline,justmedialtothefemoral artery, which is medial to the femoral branch of the genitofemoral nerve. The main complications are an arterialpuncture,infection,andrarely, deep veinthrom­ bosis (more common with long-dwelling catheters in adolescents).

Capillary Blood (Heel prick)

Indications Heelprickis a usefultechniquetoobtainarte­ rialized capillary blood for blood gas analysis, bilirubin, glucose, hematocrit and other parameters in newborns.

Technique Figure 28.3 indicates the appropriate areas to useforheelpuncturesforbloodcollection.Prewarmingthe infant's heel (using a cotton wad soaked in sterile warm waterat40°Corahottowel)isimportanttoobtaincapillary bloodgassamplesasitincreasestheflowofblood,allowing collection of blood specimen. However, it is not recom­ mended to use hot water, becausebaby's skin is thin and susceptible to thermal injury. After ensuring asepsis, a sterile blood lancet or a needle is punctured at the side of the heel in the appropriate regions as shown in Fig. 28.3. Thecentralportionoftheheelshouldbeavoidedasitmight injure the underlying bone, which is close to the skin

Fig. 28.3: Recommended sites for neonatal capillary blood sampling. Hatched areas indicate safe areas for puncture sites

surface. Blood sample is obtained by alternate squeezing and releasing of calf muscles.

Complications

The following complications may occur: (i) infection due to puncture of the calcaneus, resulting in necrotizing chondritisorosteomyelitis; (ii) calcifiednodulesoftheheel; (iii) hemolysis, resulting in falsely elevated bilirubin and potassiumlevelsfrom mechanicaltrauma; (iv)erroneously high glucose values due to alcohol in the swab; and

(v) inaccurate pC02 andp02 valuesfrompoorblood flow.

Umbilical vessel catheterization

Indications The umbilical vein is a convenient route for obtaining vascular access in newborns during the first 7-10 days oflife. Therouteiscommonlyusedfor adminis­ tration of intravenous fluids or drugs during neonatal resuscitation, whenestablishingperipheralvenousaccess is technically difficult. It is also employed as a route for central venous pressure monitoring and for performing exchange blood transfusion. Cannulation of the umbilical artery provides a route for arterial pressure monitoring orarterialbloodsamplingandalternativeaccessforexchange blood transfusion.

Contraindications Omphalitis is a contraindication; the procedure should also be avoided in presence of peritoni­ tis or necrotizing enterocolitis.

Equipment These include a 5 or 8 French catheter or feeding tube, 10 ml syringe, tape or silk suture to tie the base of the cord, normal saline for flushing, intravenous tubing and three-way connectors, a set of sterile drapes, sterile instruments (small iris forceps, needle holder and scalpel blade) and antiseptic for skin preparation.

Procedure The neonate is placed beneath a radiant warmer. Anesthesia is not required; the limbs are res­ trained gently. The abdomen and umbilicus are cleaned with chlorhexidine gluconate or povidone-iodine and sterile drapes placed, leaving the umbilical area exposed. Vital signs aremonitoredcontinuously. A sutureis looped at the base of the cord with gentle constriction to anchor the cord and limit bleeding. The cord may need to be immobilized by two artery forceps grasping cord edges at 3 and 9 o'clock position. Using a scalpel blade, the cord is trimmed to 1-2 cm above the skin.The umbilical vessels are easily identified. The umbilical vein is a single, thin­ walled, large diameter lumen, usually locatedat 12 o'clock position, while the two arteries have thicker walls with a small-diameter lumen (Fig. 28.4). The catheter or feeding tube is flushed with heparinized saline (1000 U/1) and attached to a three-way connector. A mark is placed at the length of insertion expected to place the catheter tip above the diaphragm but below the right atrium; this is calculated as 0.6 times the shoulder-to-umbilicus distance from the tip of the catheter. The closed ends of a pair of

lt.'r-H- Umbilical vein

Umbilical arteries

Fig. 28.4: Umbilical vein cannulation in a newborn. The umbilical vein is located at 12 o' clock position and is identified by its large lumen and thin walls

iris forceps are inserted into the lumen of the umbilical vein, and the lumen dilated by separating the ends of the forceps by opening it gently. Grasping the catheter with iris forceps 1 cm from its distal end, the catheter is inserted into the lumen of the umbilical vein and advanced gently inward until blood returns freely (Fig. 28.4). Resistance to advancement of the catheter indicates that the tip is in the portal vein or the ductus venosus; the catheter should be withdrawn until free flow of blood is noted. The catheter is flushed with saline and secured with a purse string suture. An X-ray is ordered to ensure that the tip of the catheter is in the inferior vena cava and not the hepatic vein or right atrium.

A similar procedure is followed for insertion ofcatheter into the umbilical artery. Since the lumen is smaller, the vessel is dilated carefully 2-3 times using a curved iris forceps and the catheter inserted gently, taking care to avoid vascular spasm. The catheter is advanced to either the high position (above the diaphragm between thoracic vertebrae T6 and T9) or the low position (above the aortic bifurcation between lumbar vertebral bodies L3 and L4). Complications Duringinsertion,vascularspasm, arterial injuryor air embolism may occur and a false tract may get created. Other complications include bleeding due to accidental disconnection of IV tubing; catheter related infection, thrombosisandembolism;andincorrectposition of the catheter tip causing cardiac arrhythmias, hepatic necrosisorportalhypertension.Vascularcomplicationsare common with the umbilicalartery catheter, particularly if placed in the low position.

Common Medical Procedures -

Suggested Reading

Anderson JD, Leonard D, Braner DAV, Lai S, Tegtmeyer K. Umbilical Vascular Catheterization N Engl J Med 2008;359:el8

Arterial Catheterization

Indications Arterial catheterization may be needed (i) to monitor blood pressure continuously, especially in hemo­ dynamically unstable patients; and (ii) to monitor frequently the arterial blood gas.

Sites and procedure Radial artery cannulation is a primary site ofarterialcannulation in infants and children. Right radial artery cannulation is performed when preductal arterialoxygen tension isrequired for evaluating and treating infants with congenital heart disease. It is often helpful to stabilize the hand and wrist on an arm board, placing the wrist in approximately 30-45 degrees extension over several gauze pads. Importantly, if the radial artery is selected for puncture or catheterization, adequacy of the palmar arterial arch should be assessed by the Allen test. The Allen test should be documented in the medical record before radial arterial puncture or catheterization is attempted.

Complications These include:

1. Disconnection of the catheter from the IV infusion

ii. Ischemia: The radial artery cannula should be with­ drawn if ischemic changes develop

Almost any medication that can be administered into a centralorperipheralveincanbesafelyinfusedintothebone marrow.Crystalloidsolutions,colloidsandbloodproducts can be safely infused, as can hypertonic solutions.

Procedure The technique of intraosseous infusion is rapid and simple. The most commonly used sites are the proximal tibia, distal tibia and distal femur (Fig. 28.5). Due to differences in cortical thickness, theproximaltibiaalong the flat anteromedial surface of the shaft, 1-2 cm below the tibial tuberosity, is the preferred site in infants and young children. The distal tibia at the junction of the medial malleolus and the shaft of the tibia is the preferred site in older children. The distal one-third of the femur along the midline and approximately 3 cm above the sternal condyle can also be used.

Fig. 28.5: Insertion sites for intraosseous infusion in the proximal tibia,

1-2 cm anteromedial from the tibial tuberosity, the distal tibia at the junction of medial malleolus and the shaft of the tibia, and the distal one-third of the femur

Technique Using aseptic technique, the site is prepared with an iodine solution. The skin is injected with 1% lido­ caine for anesthesia in the awake patient. The needle is inserted at a 10° to 15° angle to the vertical, away from the joint space (caudal for the proximal tibia, cephalad for the distal tibia and femur). Pressure is applied in a'to and fro' rotarymotion. As theneedlepasses intothe marrow, a'give away' will be felt. The needle should stand without sup­ port. Evidence for successful entrance into the marrow include (i) the lack of resistance (or a 'giveaway')after the needle passes through the cortex, (ii) the ability of the needle to remain upright without support, (iii) aspiration of bone marrow into a syringe, and (iv) free flow of the infusion without significant subcutaneous infiltration. Aspiration of bone marrow into the intraosseous needle is not alwayspossible, especially in very dehydrated patients.

The stylet is removed. Proper placement is confirmed by aspiration of bone marrow into a 5 ml syringe and free flowing of a heparinized saline flush. The needle is connec­ ted to thedesiredintravenoustubing and solution. The site is observed for extravasation of fluids into the surrounding soft tissue. Presence of swelling indicates superficial needle placement or that the bone has been pierced posteriorly.

Complications Potential complications include osteo­ myelitis, subcutaneous abscess, extravasation of fluid into subcutaneous tissue, epiphyseal trauma and fat embolism.

Lumbar Puncture

Indications The procedure is performed to obtain cerebrospinal fluid (CSF) for the diagnosis of meningitis,

meningoencephalitis, subarachnoid hemorrhage, meta­ static leukemia or benign intracranial hypertension.

Procedure The spinal cord ends at approximately the level of the L1 and L2 vertebral bodies. Caudal to L2, only

the filum terminale is present. The desired sites for lumbar puncture are the interspaces between the posterior ele­ ments of L3 and L4 or L4 and LS. These spaces are located by palpating the iliac crest. If one follows an imaginary 'plumb line' from the iliac crest to the spine, the interspace encountered is L4 to LS.

Lateral decubitus position. The patient is restrained in the lateraldecubitusposition as shown in Fig. 28.6A. The spine is maximally flexed without compromising the upper airway. Frequently, in young infants, the patient's hands can be held down between the flexed knees with one of the assistant's hands. The other hand can flex the infant's neck at the appropriate time.

The skin is cleaned with povidone-iodine solution and alcoholbeginning at theintended puncture site and spong­ ing in widening circles until an area of 10 cm in diameter has been cleaned. This is allowed to dry. Local anesthesia is used in children olderthan 1 yr of age. Thesite is anesthe­ tized by injecting 1% lidocaine intradermally to raise a

wheal, then advancing the needle into the desired inter­ spaceand injectingtheanesthetic,beingcarefulnottoinject it into a blood vessel or spinal canal.

The spinal needleis grasped firmly with the bevel facing

'up' toward the ceiling, making the bevel parallel to the direction of the fibers of the ligamentum flavum. The needle is inserted intotheskinoverthe selected interspace in the midline sagittal plane slowly, aiming slightly cepha­ lad toward the umbilicus. When the ligamentum flavum and then the dura are punctured, a 'pop' and decreased resistance are felt. The stylet is removed to check for flow of spinal fluid.

About 1 ml of CSF is collected in sterile tubes for routine culture, glucose and protein determination and cell count.

Additional samples are collected as indicated. The stylet is reinserted to remove the spinal needle with one quick motion. The back is cleaned and the puncture site covered.

Sitting position. The infant is restrained in the seated position with maximal spinal flexion (Fig. 28.68). The assistant holds the infant'shands between his or her flexed legs with one hand and flexes the infant's head with the other hand. Drapes are placed underneath the child's buttocks and on the shoulders with an opening near the intended spinal puncture site. The interspace is chosen as noted earlier and the procedure follows steps as outlined for the lateral position. The needle is inserted so it runs parallel to the spinal cord.

Complications Lumbarpuncture may be associated with headache, local back pain or infection. Brainstem hernia­ tion may occur in thepresence ofsymptomatic intracranial hypertension.

------ , -:, '-,:''

B

Figs 28.6A and B: Lumbar puncture with the child in (A) decubitus position; (B) sitting position

Thoracocentesis or Pleural Tap

Indications Thoracocentesis is performed to evacuate fluid from the patient's pleural space for: (i) diagnostic purpose, e.g. pleural effusion or empyema; or (ii) thera­ peuticpurpose, e.g. whenlarge collections of pleural fluid compromise ventilatory function.

Contraindications These include: (i) uncooperative child; (ii) uncorrected coagulopathy; and (iii) persistent inability to draw fluid (which suggests a loculated effusion). The operator should consider withholding further attempts until the procedure can be performed under radiographic guidance (CT scan, ultrasound).

Technique The first step in thoracocentesis is to ensure by clinical and radiological methods that fluid is present in the area tapped. Decubitus films are helpful in demon­ strating free fluid that shifts with movement.

The procedure (Figs 28.7A to C) is carried out with the patient appropriately positioned upright and leaning forward. The site of entry is anesthetized with local anesthetic. The landmark for evacuation of the fluid is the angle of the scapula that corresponds approximately to the eighthrib interspace. An appropriate catheter is usedover a needle. The needle is introduced immediately above the superior edge of the rib to avoid puncturing the intercostal artery and vein. Once the pleural space is entered and fluid

Common Medical Procedures -

is aspirated, the catheter is advanced as the needle is withdrawn.Thecatheterisconnectedtoathree-waystopcock and syringe (10-20 ml). It is important to control the aspiration of fluid such that air is not allowed to enter the pleural space from the outside.

Complications These include:

i.Intercostal artery puncture with severe hemorrhage

ii.Development of pneumoor hemothorax

A

B I

Figs 28.7A to C: Thoracocentesis: (A) The landmark for thoraco­ centesis is the angle of the scapula that corresponds approximately to the eighth rib interspace; (B) the needle is introduced immediately above the superior edge ofthe rib to avoid puncturing the intercostals vessels; (C) after inserting the catheter in the pleural space, the catheter is connected to a three-way stopcock and a syringe

iii.Malposition of the thoracocentesis needle, leading to injury of abdominal viscera or lung parenchymal puncture.

Abdominal Paracentesis or Ascitic Tap

Indications Ascitic tap is performed for diagnostic pur­ pose, e.g. to determine the etiology of the peritoneal fluid and to determine whether infiltration is present, or for therapeutic reason, i.e. to remove large volumes of abdo­ minal fluid which impair respiratory function.

Technique The patient is placed in a supine position and the bladder is emptied. The common sites for paracentesis are shown in Fig. 28.8. These sites are chosen to avoid puncture of underlying vessels or viscera. Usually, the left lower quadrant is preferred to the right in critically ill children because they may have caecal distension.

After the site is chosen, xylocaine is injected with a small needle to produce a skin wheal. The skin is then tilted anteriorlyso that furtherinfiltrationinto the subcutaneous tissue is in a different plane (Z tracking). A needle or over­ the-needle catheter is then advanced using the Z tracking technique and at an angle perpendicular to the skin. Continued aspiration of the needle is useduntil peritoneal fluid is aspirated. Approximately 10-15 ml of fluid is aspirated for studies. Appropriate studies may include cultures and Gram stain, cell count, cytology, amylase, LDH, bilirubin, albumin and protein. If the paracentesis is performed for therapeutic purposes, a catheter should be placed.

Complications The complications of abdominal para­ centesis may be hemorrhage, fluid leak, intestinal or bladder perforation, and hypotension, if large volumes are removed.

-Ja;T-il""-==----t-- Umbilicus

,;,-----+-- Inferior epigastric vessels

Fig. 28.8: Sites for abdominal paracentesis. The preferred sites are the linea alba (midway between the umbilicus and the pubic symphysis) and lateral to the rectus abdominis muscle

Catheterization of Bladder

Indications Bladdercatheterizationis done in bedridden patients whoneed short-term assistance. It is also required in patients with (i) polytrauma, especially for evaluation of the urinary tract in an unconscious child; (ii) shock; (iii) acuteurinaryretention; (iv) to obtain a urine specimen for urinalysis; and (v) in acute kidney injury, to monitor urine output.

Procedure The patient is restrained as necessary. The urethral meatus, penis and the perineal area are cleaned thoroughlywithapovidone-iodinesolution.AFoleycathe­ ter of the appropriate size is selected (8 Fr in the newborn, 10 Fr in most children and 12 Fr in older children). The catheter tipshouldbewelllubricatedwithsterilelubricant to minimize local trauma.

Boys. The penile shaft is gently grasped and extended to straighten out the urethral pathway. The catheter is held near the distal tip and advanced up the urethra unless resistance or an obstruction is encountered. If resistance is encountered, a smaller catheter is selected.

The catheter should be passed into the bladder all the way to the Y-connection; this is important because urine may begin to flow while the catheter is in the proximal urethra and inflation of the balloon in the urethra may lead to urethral perforation. The balloon is inflated after advancing the catheter its entire length. The catheter is taped to the child's leg.

Girls. In the girls, the principles of catheterization are similar to those inthemale. An assistant carefully spreads the labia. A well-lubricated Foley catheter is introduced into thebladder.Thecatheteris advanced its entirelength beforeinflatingthe balloon.A catheterthat is passed in its entirety is unlikelyto be inadvertently located in the small vaginaofayounggirl.Afterwithdrawingthecatheteruntil a dunking sensation is appreciated, it is secured with tape.

Complications Injury to urethra or urinary bladder and inadvertent catheterization of the vagina may occur. Absence of aseptic precautions might result in urinary tract infection.

Peritoneal Dialysis

This modality of dialytic support is used for renal replace­ ment therapy both in acute kidney injury (AKI) and end­ stage renaldisease. Catheters placedsurgicallyforchronic ambulatory peritoneal dialysis are not discussed here

Indications The modality is used in patients with AKI in whomdialysisisindicated(see Chapter16)andhemodialysis and continuous renal replacement therapies are not avail­ able, or if hemodialysis is contraindicated due to hemo­ dynamiccompromiseorseverecoagulation abnormalities. Thetechnique iswidelyavailable, inexpensiveandtechni­ cally easy to perform even in newborns, allowing gradual correction of acid-base and electrolyte imbalance without need for anticoagulation.