Pediatric Anesthesia Presented by Danyel Dorn RN MSN
Pediatric Anesthesia Presented by: Danyel Dorn RN, MSN, CPN, Clinical Nurse Educator-Pediatric Service Line
Purpose • The perianesthesia registered nurse will describe the pharmacology and perianesthesia considerations in caring for the pediatric patients who receive anesthesia agents, in order to provide a safe Postanesthesia period for the patient.
Competency Statement • Demonstrate knowledge of anesthesia agents pertinent to preparation and administration for the pediatric perianesthesia nursing.
Pediatric Factors • Physiological response of infants and children to medication is mediated by a number of factors • • Body composition Protein binding Body temperature Distribution of cardiac output Functional organ maturity Maturation of the blood-brain barrier Relative size of liver and kidneys Presence of congenital malformations
Education for Patient & Family • Describe anesthesia in terms the patient may understand according to their developmental age and choosing age appropriate language to describe the experience • Describe this as a “special type of sleeping medicine” – scary phrase = “put you to sleep” (pets get put to sleep) • Reassure the child they will stay asleep though the entire procedure and not wake up in the middle
Education Cont. • Initiate teaching associated with various medications • Pre-procedural medications and anesthesia or pain medications can increase risks for falls • Utilization of pre-procedural sedation decreases anxiety and thus decreases the potential of behavioral changes and/or nightmares secondary to fear associated with pain.
Anesthesia • Anesthesia: is the absence of sensation, a reversible alteration in awareness observed on a continuum from an awake, conscious state to an unconscious state • Inhalation agents are used for the induction and maintenance of general anesthesia • When inhalation agents are combined with adjuvant, such as opioids, muscle relaxants, barbiturates, nitrous and oxygen, a balanced technique is achieved that results in blocked perception and awareness of painful stimulus
Distribution of Anesthesia • Distribution: distribution of anesthetic vapors is dependent on organ perfusion/cardiac output and the blood-tissue partition coefficient
Uptake of Anesthesia • Uptake: Uptake (alveolus to blood) of anesthetic vapors is dependent on the agent’s solubility and pulmonary blood flow/cardiac output and the concentration gradient • Amount of agent absorbed is relevant to the degree of organ perfusion, the duration of anesthetic exposure, use of other medications, as well as the patient’s physical status (This is especially important in children with congenital heart issues) • Highly perfused organs: brain/heart/kidneys • Moderately perfused organs: skeletal muscle, skin • Poorly perfused organs: tissues, ligaments, bone, fat cells
Minimum Alveolar Concentration (MAC) • MAC refers to the lowest concentration of the inhalation agent that prevents movement in 50% of patients when subjected to noxious stimuli • This is not to be confused with Monitored Anesthesia Care, sometimes referred to as “MAC” • A lower MAC value represents a more potent volatile anesthetic • With concurrent use of other agents (opioids), a lower concentration of vapor is needed to achieve anesthesia
Elimination/Recovery • Occurs in reverse order of induction • Primary elimination is pulmonary • When the agent is stopped, absorption uptake ends and the agent the begins to flow back to the lungs with returning blood along the concentration gradient and are eliminated in the exhaled breath
Elimination/Recovery Cont. • Gases are exhaled as spontaneous respirations return as well as by controlled reinflation • Those organs of mild perfusion store these agents more readily, are slow to return agents to the circulatory system and can slow the process of exhalation and recovery from inhaled agents • Some agents also have a metabolic elimination involving hepatic and/or renal function • Inhalation anesthetics have only a negligible elimination via metabolism • Also influenced by: duration of anesthesia, co-administered drugs and patient’s physical status
Pharmacokinetics • Pharmacokinetics = the study of what the body does to a drug • Factors include: • • • Blood solubility Cardiac output Metabolism Tissue equilibration Extent of tissue perfusion age
Pharmacodynamics • Pharmacodynamics = the study of what the drug does to the body • Effects on the body include: • Impaired CNS synaptic transmission • Increased cerebral blood flow • Sensitized myocardium to dysrrhymogenic actions of catecholamines • Dose dependent depression of spontaneous ventilation • Dulled ventilatory responsiveness to hypoxemia and hypercarbia • Dose dependent reduction of cardiac output • Obtunded laryngeal and pharyngeal reflexes • Bronchodilation • Relaxation of smooth muscle and motility
Stage 1: Anesthesia and Amnesia • Initiation of anesthesia to loss of consciousness • Patient can follow simple commands • Protective reflexes remain intact
Stage 2: Delirium Loss of consciousness to loss of lid reflex Respirations irregular May be passed through quickly with newer inhalation agents “Danger Zone” – neurons that inhibit emotions are not functional • Patient can be caught in this excitable state and may exhibit untoward responses such as vomiting, laryngospasm, cardiac arrest and emergence delirium • Increased risk of laryngospasm in Stage II, especially in children • •
Stage 3 & 4 Anesthesia • Stage 3: Surgical Anesthesia • Absence of eyelash response, blink and swallowing reflexes • Stage 4: Cessation of Respiration to Circulatory Collapse • Considered overdose of anesthetic • Stages of anesthesia are more readily observed during emergence and recovery than with induction with newer agents
Emergence Delirium • A dissociated state of consciousness demonstrated by responsive or unresponsive agitation • Duration is usually less than 10 minutes but can be as long as 45 minutes • Causes include: preexisting cognitive impairment, medications (such as inhalation agents, benzodiazepines, atropine, ketamine, droperidol), hypoxia, hypothermia, bladder distention, cerebral hypoxia, gastric dilation, alcohol withdrawal and hypercarbia
Emergence Delirium Cont. • Demonstrated in less than 10% of patients though incidence in pediatrics is 12 -30% • This is dependent upon the anesthetic agent, higher with sevoflurane and desflurane, lower with TIVA, relatively low with isoflurane • Preoperative benzodiazepines may elicit a paradoxical effect leading to irritability, aggressiveness and confusion
Emergence Delirium Cont. • Symptoms include: agitation, combativeness, alternating periods of excitement and disorientation with lethargy, disturbances in thought, cognition and orientation and use of profanities • Patient appears to look through the nurse and is difficult to console • Always rule out hypoxemia: medicate only when oxygen demands are met
Emergence Delirium Cont. • Treatment • Institute safety precautions for patient and staff • Physiologic or pharmacological causes must be investigated • Short acting opioids
Delayed Emergence • Lack of responsiveness or failure to return to baseline after administration of an anesthetic • Causes include: inadequate ventilation and oxygenation may indicate an under stimulated patient in PACU, impaired metabolism of intraoperative medications/self-administered medications prior to surgery, metabolic insult, intraoperative cardiovascular accident (CVA), seizure, increased ICP, organic dysfunction and ongoing residual neuromuscular blockade
Delayed Emergence Cont. • Symptoms = lack of responsiveness despite having allowed sufficient time for metabolism and elimination of anesthetic • Treatment is specific to determined cause
Similarities/Differences of the Inhalation Agents • Inhalation induction is most commonly used in the pediatric population for several reasons • Requires no previously inserted peripheral intravenous line • Decreases potential anxiety associated with needles or injections • Child can play with some equipment such as oxygen mask, prior to entering the operating room • Child can assist with picking out a “flavor” for the mask (bubble gum/cotton candy) • Any position can be utilized for induction with a mask, sitting, lying down, on parent or caregiver’s lap
Physiology of Pediatric Inhalation Induction • There is ease of maintenance of the pediatric patient’s spontaneous respirations • The airway may lose muscle tone which can lead to partial obstruction as the tongue falls to the back of the mouth and may lie against the palate • Auscultate for high pitched inspiratory sounds which would originate from the region of the vocal chords (possible early indicator of laryngospasm)
Physiology of Pediatric Inhalation Induction cont. • Auscultate for low pitched sounds which would most likely originate in the supraglottic area (upper airway obstruction) • Expiratory sounds may indicate wheezing and/or bronchospasm • Treatment plan includes supporting the airway with continuous positive pressure and possibly inserting a oral or nasal pharyngeal airway
Gaseous Agents • Nitrous Oxide • Hypnotic and analgesic effects with minimal respiratory depression • Rapid onset, may be used early in induction • Low potency • Strong analgesic and weak anesthetic: usually used in combination with other agents • May contribute to an increase in postoperative nausea and vomiting in the pediatric population
Nitrous Oxide Cont. • To prevent hypoxia, must mix with 100% O 2 for delivery and not with room air • “Fink Phenomenon” diffusion hypoxia in the PACU • Diffusion of nitrous from the blood stream into the lungs displaces the alveolar O 2 and produces diffusion hypoxia • Treatment : O 2 mask, deep breaths and exhaling to wash out nitrous • Analgesic effect prominent: enhanced by opioids
Nitrous Oxide Cont. • Minimal cardiovascular effects: relative constant cardiac output, stroke volume, hear rate, and blood pressure • Potential for increased nausea: air trapping in middle ear • Expanded or retracted pockets of air • Does not relax skeletal muscle • Offset of effects 5 -10 minutes assuming adequate ventilation
Volatile Agents • Volatile agents store as liquid at room temperature, but vaporize easily for administration by inhalation via anesthesia vaporizers • Effective for inducing or maintaining anesthesia, or both • Postop shivering mechanism is not known and can happen with all volatile agents • Uptake of volatile agents is faster in children due to the increased respiratory rate and cardiac index
Isoflurane (Forane) Inexpensive but does have a noxious smell Has bronchodilator effect Effective fro deep extubation due to a slower wake up Promotes and potentiates neuromuscular blockade Coronary artery and peripheral vasodilator, less myocardial depression • Stabilizing cardiovascular effects: less incidence of brady arrhythmias • Absorption and excretion almost exclusively by lungs • Used frequently in pediatric neurosurgical cases • • •
Desflurane (Suprane) • Not recommended for pediatrics due to high incidence of airway irritation • High incidence of laryngospasm, emergence agitation and PONV
Sevoflurane (Ultane) • Least airway irritation: least likely to cause coughing, excessive salivation or laryngospasm • Depresses central respiratory muscle function • Rapid changes in anesthesia depth (rate of induction is faster) • Has an intermediate effect in increasing ICP • Least irritating of all volatile agents (sweet smell) • Useful in ambulatory setting: has replaced halothane for pediatric population use • No predisposition to arrhythmias • Does not break down into carbon monoxide as others might • May be useful in patients with hepatic or renal insufficiency
Pediatric Anesthesia Adjuncts • Midazolam: Short acting benzodiazepine, rapid onset 20 -30 minutes • Produces sedation and anxiolysis, may reduce incidence of vomiting, but no pain control • May cause some decrease in respiratory rate and loss of upper airway tone • Dosage is generally 0. 25 -0. 5 mg/kg PO, but may be administered IV • 0. 2 mg/kg intranasal
Pediatric Anesthesia Adjuncts • Clonidine: highly selective alpha 2 -adrenergic receptor that has demonstrated not only sedative and anxiolytic effects, but also contributes to analgesic control • Can be administered PO, intranasal, IV or intramuscular • Dosage is generally 3 -4 mcg/kg • Has minimal respiratory depression
Pediatric Anesthesia Adjuncts • Dexmedetomidine: Highly selective alpha 2 -adrenergic receptor that has demonstrated not only sedative and anxiolytic effects, but also contributes to analgesic control • May cause some mild respiratory depression but may also unmask baseline obstructive sleep apnea or other sleep disordered breathing issues, can cause bradycardia • Dosage is generally 1 -2 mcg/kg intranasal
Pediatric Anesthesia Adjuncts • Ketamine: sometimes used with developmentally delayed patients when midazolam only promotes a loss of inhibition • Can also be used as an induction agent • Dosage ranges from 0. 5 mg/kg to 3 mg/kg • Contradictions to use of ketamine in children include: active upper respiratory infection, increased ICP, psychiatric or seizure disorders, full stomach or hiatal hernias • Induction agent
Pediatric Anesthesia Adjuncts • Propofol: major concern for propofol in children is the pain on administration • Can have modest reduction in blood pressure if given as a bolus • Benefit includes reducing the incidence of PONV
Nursing Considerations • Continuous cardio/resp. monitoring • Respiratory/ventilation assessment: rate, quality and depth of respirations • Administration of O 2 as indicated • Deep breathing and stimulation • Knowledge of co-administered medications including: sedatives, hypnotics, opioids, neuromuscular blockers including dose/route and time administered and reversal agents • Analgesic requirements: administration of appropriate pain medications • Knowledge of elimination of inhalation agents and their offset times for assessment of CNS return to baseline
Nursing Considerations • Knowledge of potential adverse effects and toxicities: • Respiratory depression/airway obstruction/hypoxemia/atelectasis/hypo or hyper ventilation • Hypo/hypertension • Emergence delirium • Nausea and vomiting • Arrhythmia interpretation • Toxicity: nephro/hepatic/neuro • Malignant hyperthermia • Motor blockade secondary to inadequate reversal • No residual analgesic effect
Reference • ASPAN (2016). A Competency Based Orientation and Credentialing Program for the Registered Nurse Caring for the Pediatric Patient in the Perianesthesia Setting.
Answers 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. C B D B B A B C
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