Pre-Operative Evaluation in Paediatric Patients

Pre-Operative Evaluation in Paediatric Patients

Review Article

Preoperative evaluation in a paediatric patient is amajor component of paediatric anaesthesia practice thatcontri-butes significantly to a favourable outcome [1]. Athorough understanding of the physiological, pharmaco-logical and psychological differences in a child is essentialin order to assess the special needs of the child for ‘a’surgical procedure keeping in mind the components ofpreoperative assessment which is broadly similar to that inan adult.

How is preoperative evaluation in a child differentfrom that of an adult?

• First and foremost, children must always be assessedin presence of their parent or caregiver.

• There is an inherent difficulty in communication withthe younger child and sometimes even an older child.

• The medical problems in a child belong to a differentspectrum of illnesses as compared to the adultpopulation as diseases in childhood are often due tocongenital defects or acute problems such as upperrespiratory illnesses.

Preoperative evaluation consists of the followingsegments

• Goals and objectives of preoperative evaluation

• Risk assessment

• Disease detection and optimization of co-morbidconditions

• Preoperative fasting criteria

PRE-OPERATIVE EVALUATION IN PAEDIATRIC PATIENTS

Sharmila AhujaProfessor, Department of Anaesthesiology & Critical Care, University College of Medical Sciences &

Guru Teg Bahadur Hospital, Delhi 110 095, India.E-mail: [email protected].

Preoperative evaluation and preparation of the child for surgery forms a major consideration in paediatricanesthesia practice. Special considerations include evaluation of the medical condition, assessing thepsychological status of the child, allaying anxiety of the child as well as the parent and understanding thespecial needs of the surgical procedure planned.

This short review addresses the goals and objectives of preoperative evaluation in a child, with brief inputsabout some special situations such as a child with Upper Respiratory Infection and the Fearful child.

Key words: Preoperative assessment, Paediatric.

• Preanaesthetic medications

GOALS AND OBJECTIVES OF PREOPERATIVEEVALUATION

Preoperative evaluation of a patient scheduled forsurgery has become an integral part of modern dayanaesthesia practice [2,3]. Anaesthesiologists are increa-singly looked upon as perioperative physicians andundertake an active role in the management of the surgicalpatient right from the preoperative phase up untilpostoperative recovery. Also in the current scenario ofmedicolegal issues in health care, obtaining anddocumenting information about patients’ medical history,assessment of risk and obtaining informed consent havebecome important issues, both in adult and paediatricanaesthesia practice. Thus the goals of preoperativeevaluation would include:

• To obtain baseline information about patients’current physical status by thorough clinicalexaminations and appropriate investigations

• Detection of co-morbid conditions and optimizationof these if any, e.g. URI, anaemia

• Assessment of risk and obtaining informed consentfrom parent / guardian/child as appropriate

• Allaying anxiety of child/parent by effective com-munication and premedication wherever applicable.

Objectives

• To provide safe anaesthesia care by planning

105 Apollo Medicine, Vol. 8, No. 2, June 2011

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Review Article

anaesthesia management following preoperativeevaluation

• Plan for postoperative pain relief measures

• Make suitable arrangements for day care surgerywherever applicable.

RISK ASSESSMENT

No single assessment or grading method has beenestablished to quantify risk associated with surgery andanaesthesia, the most common reasons being:

• Individual patient variability

• Types of surgical procedures with varying risksassociated with the specific procedure

• Risks may vary depending on location of the surgicalprocedure, e.g. the radiology suite.

The universally accepted ASA classification systemaddresses the physical status of the patient based only onpatients’ preoperative medical history and examination. Itincludes 6 grades, ASA Grade I till Grade VI, ‘E’ beingadded to the grade if the procedure is an emergency. Thisis true for all age group patients.

American Society of Anaesthesiologists PhysicalStatus Classification (Miller’s Anaesthesia, 7th edition).

ASA 1: Healthy patient without organic, biochemical orpsychiatric disease.

ASA 2: Patient with mild systemic disease, e.g. mildasthma or well controlled hypertension. Nosignificant impact on daily activity. Unlikely tohave impact on anaesthesia and surgery.

ASA 3: Significant or severe systemic disease that limitsnormal activity, e.g. renal failure on dialysis orclass 2 congestive heart failure. Significantimpact on daily activity, probable impact onanaesthesia and surgery.

ASA 4: Severe disease that is a constant threat to life orrequires intensive therapy, e.g. acute MI, res-piratory failure, requiring mechanical ventilation.Serious limitation of daily activity, major impacton anaesthesia and surgery.

ASA 5: Moribund patient who is equally likely to die inthe next 24 hours with or without surgery.

ASA 6: Brain dead organ donor.

Drawbacks of ASA grade: It does not take into accountthe patient’s age, type of surgery or anaesthesia or locationof the procedure. Therefore cannot quantify risk.

Of the other various assessment tools such asGoldman’s criteria, the Joint ACC/AHA Guidelines forpatients with cardiac disease for non-cardiac surgery havebeen well accepted. However, this (updated in 2007) ismore applicable in the adult population.

Despite various limitations of risk assessment, thevalue of performing preoperative evaluation and itscontribution towards effective anaesthesia managementremains undisputed.

DISEASE DETECTION AND OPTIMIZATION OFCO-MORBID CONDITIONS

As mentioned earlier, it is important to realize thatchildren are more prone to acute illnesses speciallyinfectious diseases or manifest changes due to acongenital anomaly/defect.

A careful history obtained from the parent includingcurrent and past medications and/or focused clinicalexamination can provide accurate diagnosis in most cases.Important considerations in history taking are:

• Antenatal and neonatal history in case of infants(prematurity and gestational age).

• H/o familial anaesthesia related conditions – such asmalignant hyperthermia, pseudocholinesterasedeficiency, inherited metabolic disorders, musculardystrophy etc.

• Previous records of medical illnesses and treatmentincluding previous anaesthesia to help identify anyprevious anaesthetic problems.

• History of allergy to drugs or substances.

• Allergy to latex is the commonest cause of intra-operative anaphylaxis in children and must beexcluded by careful history taking from the parent.

• Allergy to various foodstuffs and drugs must also becarefully elicited.

• Physical examination must focus on cardiovascular,respiratory, airway (specially dentition) and neuro-logical system wherever indicated. Special concernsinclude locating venous access sites and inspectionof the site for regional anaesthesia and nerve blocks.

• Taking preoperative weight of the child is importantas all drug dosages are calculated as per body weight.

INVESTIGATIONS

Current opinion regarding routine preoperativeinvestigations such as hemoglobin estimation and urineanalysis in a healthy child is deemed unnecessary as the

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benefits of these reports towards safe anaesthesia care arenot proven.

The recent trend is to target specific investigationsdepending on age, pre-existing medical conditions or typeof surgery.

Examples

• Hb estimation is desirable in a neonate or ex-premature infant in whom Hct less than 30% isassociated with high incidence of postoperativeapnea.

• Children undergoing certain procedures such asadenotonsillectomy, coagulation profile may bedesirable though it is not routinely followed incountries outside the UK.

• Children with history of bleeding tendencyundergoing certain procedures such as neurologicalsurgeries, coagulations screening is justified.

• Children from certain countries susceptible to sicklecell anaemia or Hb pathies such as Central Africa,north east Saudi Arabia and East Central Indiashould be tested preoperatively for sickle cell disease(sodium metabisulphite screening test or sickledextest).

Special Situations [4]

• Child with an Upper Respiratory Tract Infection(URTI).

• Child with a murmur

• Child with history of asthma

• The fearful child

• Child with endocrine disorder – DM

Of these, the 1st and 4th conditions will be discussed.

Child with an URTI (Fig.1).

Key issues:

• Whether/when to cancel or proceed?

• Increased incidence of airway related problems –laryngospasm, bronchospasm, episodes ofdesaturation etc.

Despite various suggested guidelines, decision toproceed or cancel surgery in presence of respiratorysymptoms remains controversial.

The fearful child

Common causes:

• Terrifying past experience

• Fear of pain

• Fear of unknown

Suggested approaches to a fearful child

• In an older child who can verbalize his/her concerns,reassurance, establishing a rapport and explainingthe induction technique can often overcome thisproblem.

• In a younger child, allaying anxiety in the parent(transmitted anxiety) and a suitable premedicationgoes a long way in dealing with the situation.

PREOPERATIVE FASTING

The main concerns of prolonged fasting in children arehaving an irritable hungry child at induction, risk ofhypoglycemia in younger children specially neonates, anddehydration. There is evidence to suggest that clear liquids(water, apple juice) can be safely allowed in children upto2-3 hours before induction of anaesthesia.

However, in order to avoid risk of pulmonaryaspiration, preoperative fasting guidelines have beendeveloped for solids and types of liquids (Table 1).

PREMEDICATION

The aims of premedicating a child are:

• To have a cooperative calm child at induction

• Avoid anxiety related to separation from parents

Routes of administration: include oral, sublingual, IM,IV or rectal.

Each route has its own drawbacks and must be chosenaccording to the need of the individual patient.Premedication is not necessary in children <6 months age.

Oral route is the most preferred and provides effectiveand reliable sedation in children, the only drawback beingsplitting out or vomiting following administration.

The short acting benzodiazepine midazolam has beenaccepted as the most preferred drug for achieving thegoals of premedication in children weighing less than 20kg because of its faster onset of action and lesser sideeffects.

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Fig.1. Algorithm for the assessment of the child with an upper respiratory tract infection (Textbook of Paediatric Anaesthesia,ed: Bingham, Lloyd-Thomas & Sury).

Most popular route of administration is oral, in adosage of 0.5 mg/kg body weight given ideally at 20-30min prior to induction of anaesthesia.

Other sedative drugs

Older drugs such as chloral hydrate and phenothiazine

derivatives are losing popularity due to various sideeffects associated with their use.

Oral clonidine is emerging as a popular alternativedue to its sedative analgesic, antiemetic and calmingeffects. It is said to reduce emergence agitation associated

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with inhalation agents such as sevoflurane. Dosage is 4μg/kg to be given 60-90 min prior to induction ofanaesthesia.

Topical local anaesthetic agents

If IV induction is planned, use of EMLA (eutecticmixture of lignocaine and prilocaine) or Ametop gel (4%Amethocaine) on the chosen venous puncture site is veryuseful in reducing the pain of venepuncture and isroutinely used in most institutions in the west.

Drawbacks

(a) Long application time (1 hour for EMLA cream, 30-45 min for Ametop gel)

(b) Blanching at site of application thereby makingvenepuncture difficult.

Ametop gel has been found to be superior to EMLAcream as it causes less vasoconstriction.

Anticholinergics

Atropine and glycopyrolate are not used in routinepractice but may be given in special circumstances such asbefore airway surgery to reduce secretions or in the veryyoung child to prevent bradycardia at induction (oralatropine 0.02 mg/kg 30 min prior to induction).

To summarize

• Preoperative evaluation of the child must always beperformed in the presence of parent/caregiver to

obtain relevant information.

• Establishing a rapport with the child and allayinganxiety of child as well as of the parent goes a longway in conduction of smooth anaesthesia induction.

• It is important to obtain informed consent fromparent / caregiver about risks and procedures (e.g.epidural block).

• Being aware of special situations encountered in achild (e.g. child with URI etc.) for optimization, andproper planning, will therefore ensure provision ofsafe anaesthesia in these vulnerable group ofpatients.

Oral premedication is preferred in children, the drug ofchoice being midazolam.

REFERENCES

1. Liam Brennan. Preoperative assessment. In Hatch &Sumner’s Textbook of Paediatric Anaesthesia. Eds;Bingham, Lloyd-Thomas & Sury. 3rd edition. 253-264.

2. Kar-Binh Ong. Preoperative preparation and medication.In Hatch & Sumner’s Textbook of Paediatric Anaesthesia.Eds: Bingham, Lloyd-Thomas and Sury. 3rd edition. 265-272.

3. Stephen Fischer, Angela M Bader and Bobble JeanSweitzer. Preoperative evaluation. In Miller’s Anaes-thesia. Ed: Ronald Miller. 7th edition. 1001-1066.

4. Anaesthetic Management of difficult and routinepaediatric patients. Ed. Frederic A. Berry. ChurchillLivingstone. 2nd edition.

Table 1. Fasting guidelines for paediatric patients

Age Clear fluids Breast milk Formula milk Solids

Over 1 year 2 hrs – 6 hrs 6 hrs6-12 months 2 hrs 4 hrs 6 hrs 6 hrsLess than 6 months 2 hrs 3-4 hrs 4-6 hrs 6 hrs

(Textbook of Paediatric Anaesthesia, 3rd ed. Bingham, Lloyd Thomas & Sury, page 267).

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