소아마취의 최신 지견

1) Anesthesia for neonate and ex-premature infants ··················141

인제의대 방시라

2) 소아를 위한 심폐소생술 ···············································································145

서울의대 김진태

대한소아마취학회

제89차 종합학술대회

프로그램 및 초록

대한소아마취학회

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Anesthesia for neonate and ex-premature infants

인제 학교 의과 학 해운 백병원 마취통증의학과

방 시 라

산과학과 신생아학의 발 은 신생아 생존, 특히 preterm

neonate의 생존 증가에 많은 기여를 하 다. 많은 수의 생존

미숙아들은 생애 기에 크고 작은 수술이 필요한 경우가

많아 이에 마취과 의사들은 다양한 신생아 수술을 경험하

게 되어 신생아 생리와 미숙아들의 합병증 등에 한 이해

와 주의가 필요하게 되었다.

Neonatal physiology

Pulmonary

A. Transition phase and persistent pulmonary hypertension of

the neonate

At birth - 략 35 ml의 양수가 폐에서 배출되며 폐확장

이 이루어지며 호흡이 시작됨.

기에 폐는 매우 stiff (compliance very low):

first breath require negative forces ＞ 70 cm H2O.

Pulmonary vascular resistance (PVR) 이 빠르게 감소하며

ductus arteriosus가 출생 후 1−15 hours 사이에 닫힘. PVR

정상화는 진 인 과정이며 3−4일 정도가 소요. ductus ar-

teriosus와 foramen ovale의 해부학 폐쇄는 몇 달이 소요.

출생 후 normal tidal ventilation은 10분 내에 normal FRC

는 20분 내에 도달하게 됨.

Persistent pulmonary hypertension of the neonate (PPHN):

hypoxia, hypercarbia, or acidosis can cause a sudden increase

in PVR and a return to a fetal circulatory pattern. PPHN is an

acute, life-threatening condition, as shunt fraction increases to

70% to 80%, and profound cyanosis results. Many factors dur-

ing anesthesia can affect this transitional state. Anesthetic agents

can markedly diminish systemic vascular resistance (SVR), re-

sulting in right-to-left shunt. Hypoxia or hypercarbia and acido-

sis from inadequate ventilation can increase PVR, with similar

effects on shunt.

Summary of Pulmonary differences with adults

1. Higher O2 Consumption

2. Higher closing volume

3. Higher MV:FRC

4. Compliant ribs and less Type 1 muscle in the diaphragm

B. Airway anatomy

Head: much larger compared with body size than that of

older children

Short neck, larger tongue

Higher and anterior larynx: cords located at C4 in the infant

compared with C5 or C6 in an adult.

Epiglottis: soft and folded

At the cricoids ring, 1 mm of edema results in a 60% re-

duction in the cross-sectional area of the airway, causing in-

creased airway resistance and increased work of breathing.

Laryngomalacia is also common in premature infants and can

result in obstruction.

Cardiovascular

Reduced ventricular compliance and less ability to increase

contractility → relatively dependent on heart rate to increase

cardiac output.

According to Barash, the neonatal heart is only capable of

increasing CO by about 30% (the adult, by contrast, can in-

crease CO by 300%).

Bradycardia: particularly dangerous in the neonate.

Hypoxemia, which can precipitate bradycardia, should be

vigorously avoided.

Diminished baroreceptor response to hypotension, and have

difficulty mounting a tachycardiac response.

Renal

Nephronogenesis: complete at 34 weeks’ gestation

Term neonate: as many nephrons as an adult, although they

are immature, with a glomerular filtration rate (GFR) approx-

imately 30% of the adult’s GFR.

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With increasing cardiac output and decreasing renal vascular

resistance, renal blood flow and GFR increase rapidly over the

first few weeks of life, and reach adult levels by about 1 year

of life. The diminished function over the first year is well bal-

anced to the infant’s needs because much of the neonate’s sol-

ute load is incorporated into body growth, and excretory load

is smaller.

Temperature regulation

Given a large surface area, small body volume, and minimal

insulation, neonates are extremely prone to heat loss. Any de-

gree of cold stress is detrimental and increases metabolic de-

mands in the neonate.

Preterm mortality

Intensive medical care should be initiated at 26 weeks of

gestation, aggressive resuscitation: not widely recommended for

infants born before 23 weeks gestation ‘grey zone’: gestational

age - play a role in influencing outcome.

Infants born at 22−25 weeks gestation

: in addition to gestational age, four factors as important in

the outcome of extreme prematurity.

Higher birth weight,

Female sex,

Use of antenatal steroids,

Singleton birth

Morbidity and mortality: remains high (one study estimating

a mortality rate of 89% for infants weighing 401−500 g)

Almost all the survivors in this extremely low birth weight

group suffered from considerable morbidity

Preterm morbidity

A. short-term morbidity

respiratory distress syndrome,

bronchopulmonary dysplasia,

persistent patent ductus arteriosus,

intraventricular hemorrhage,

periventricular leukomalacia,

retinopathy of prematurity,

necrotizing enterocolitis.

B. long-term morbidity

neurodevelopmental sequelae [cerebral palsy (CP), cognitive

delay, blindness, deafness,

chronic lung disease,

feeding difficulties,

subglottic stenosis following prolonged endotracheal intubation.

Brain development: particularly vulnerable during the second

and third trimesters.

Infants born at 22−26 weeks gestation :

high risk for hypoxic/ischemic brain injury

intraventricular hemorrhage,

→ frequently result in subsequent neurodevelopmental

sequelae.

Anesthetics and neurodevelopment

The current controversy can perhaps be summarized in sev-

eral points, as follows:

A. Exposure to anesthetic agents, at clinically appropriate

doses, at the peak of synaptogenesis can cause widespread

neuroapoptosis in several species of animals, including pri-

mates. A clinically appropriate dose is the minimum necessary

to induce anesthesia in the species. In some species, and with

some agents, this dose also results in significant mortality, in-

creasing the difficulty of interpreting the significance.

B. Synaptogenesis in rats occurs postnatally over the first 2

weeks of life. An analogous period in humans would range

from the third trimester of pregnancy through the first 3 years

of life. Whether the child might be susceptible to anesthetic

toxicity during this entire period is unknown. Other studies

looking specifically at neurodevelopment suggest that a post-

natal 7-day-old rat more closely corresponds to the human fetus

between 17 and 22 weeks of gestation. Elucidation of the crit-

ical period is of prime importance in anesthetic management.

C. The animal studies of apoptosis involve anesthesia with-

out surgery. There is some indication that the presence of sur-

gical stress may alter the response to anesthetics.

D. Abnormal behaviors and learning have also been shown

in animal studies after anesthetic exposure.

방시라：Anesthesia for neonate and ex-premature infants

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회Fig. 1. Post-operative monitoring of the former preterm infant with a post-conceptual age (PCA) ＜ 60 weeks. Acta Anaesthesiol Scand. 2006;

50(7): 888-93.

E. Initial extremely limited studies of children after anes-

thetic exposure as infants are suggestive, but difficult to

interpret. It is impossible to separate the effects of anesthesia

from the effects of surgery; the fact that in Wilder and col-

leagues study an effect was seen only with multiple anesthetics

might be related to dose, but could be related to other con-

founding effects, such as more severe illness.

F. The effects under examination are subtle, and difficult to

categorize and measure. The effects of fetal ethanol exposure

were first elucidated because of marked craniofacial abnormal-

ities, rather than more subtle developmental problems.

G. As has been proposed, the careful multicenter FDA ini-

tiative may be needed to determine the clinical impact of the

problem.

결론 으로 신생아 마취에 해 신경학 손상을 최소화

하기 한 방안을 고려해 보면,

A. The benefits versus the risk of delay in surgical proce-

dures, particularly if performed in premature infants, should be

carefully considered. Similar concerns could be raised in older

children if the procedure is elective.

B. It seems reasonable to perform a “simple” anesthetic.

There is virtually no extensive experience with many anesthetic

agents in neonates. This lack of extensive experience is not

unusual in neonates or pediatrics in general, but may be of in-

creased importance given the small therapeutic margin of most

anesthetics. There would seem to be little utility in the combi-

nation of agents, such as midazolam, propofol, and isoflurane,

when a single agent could be as easily used. Whether the use

of multiple agents could decrease the required dose of each,

and whether this would be beneficial is impossible to answer.

One preference is to use a predominant narcotic technique in

premature infants who may be most at risk, when appropriate.

Fentanyl has little, if any, activity as either an NMDA antago-

nist or GABA agonist. It is well tolerated hemodynamically,

and effective at preventing the surgical stress reaction. This

particular technique may prevent extubation, but in this gen-

erally ill population, this is not usually a consideration. The

possibility of recall with a pure narcotic technique can be

raised, but with a dose adequate to prevent the stress response,

this may not be important.

Summary of recommendations for the anesthetic

care of the expremature patient

ㆍDelay nonessential surgery until apnea risk is reduced:

Post-pone surgery until PCA _ 60 weeks

ㆍWhen surgery cannot be delayed, plan for overnight admis-

sion and monitoring (at least 18 hours (?) in those still at

risk for apnea.

ㆍOptimize medical conditions, including reactive airway dis-

ease and gastroesophageal reflux, prior to surgery.

ㆍRecognize limitations of all expremies, even those that are

not obvious (pulmonary function, developmental): Assessment

of comorbidity or anaemia.

ㆍConsult with the patient’s physicians regarding ongoing med-

ical problems.

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ㆍChoose appropriate anaesthesia technique

ㆍPlan for intraoperative bronchospasm.

ㆍConsider postoperative intensive care unit admission prior to

surgery to ensure availability, should it become necessary.

ㆍDecide level of post-operative monitoring (see Fig. 1)

References

1. Martin RJ, Fanaroff AA, Michele C. WalshFanaroff and Martin’s

Neonatal-Perinatal Medicine: Diseases of the Fetus and Infant, 9th

ed. pp 597-614.

2. Laura S. Seminars in Anesthesia, Perioperative Medicine and Pain

(2006) 25, 117-123.

3. Walther-Larsen S, Rasmussen LS. The former preterm infant and

risk of post-operative apnoea: recommendations for management.

Acta Anaesthesiol Scand. 2006; 50(7): 888-93.

4. Davis P, Cladis F, Motoyama E. Smith’s Anesthesia for infancts

and children, 8th ed. 512-588.

5. Wilder RT, et al: Early exposure to anesthesia and learning

disabilities in a population-based birth cohort, Anesthesiology 110:

796, 2009.

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소아를 위한 심폐소생술

서울 학교 의과 학 마취통증의학교실

김 진 태

Table 1. BLS

성공 인 심폐소생술을 해 가장 효과 인 방법은 시뮬

인션을 통한 한 교육이라고 생각한다. 심폐소생술에

는 basic life support (BLS), ACLS (advanced cardiovascular

life support), PALS (pediatric advanced life support)가 있고,

미국 심장 회(American heart association)에서는 이를 기

로 교육을 하고 있다. 한심폐소생 회에서도 이를 기 하

여 provider와 instructor 배출에 힘쓰고 있고, PALS provider,

instructor 과정도 이에 포함 된다. PALS provider 과정은

BLS test, skill station (management of respiratory emergencies,

rhythm disturbance/electrical therapy, vascular access), core

case simulations and discussions로 구성되어 있다.

Table 1은 BLS 정리 표이다. 소아의 경우 어도 흉부 앞

뒤 직경의 1/3 깊이로 어도 100회/분으로 가슴 압박을 해

야 한다. 소아에서 의료인이 2명일 경우 15：2로 압박과 호

흡을 시행하고 그 이외의 경우는 모두 30：2로 시행한다.

소아가 반응을 하지 않을 경우 의료인의 경우 맥박을 진

할 수 있는데(brachial artery in infant, carotid or femoral ar-

tery in a child), 10 이상 넘지 말아야 한다. 맥박이 60회

이상이고 호흡계 문제 일 경우 분당 12−20회의 호흡을 시

행한다.

Fig. 1은 소아에서 BLS algorithm이다. 이때 주의 할 은

압박 후 완 히 가슴이 펴지도록 해야 하는 것, 가슴 압박

이 단되는 시간을 최소화해야 하는 것, 그리고 과환기를

피하는 것이다. 소아의 경우는 hand-only CPR이 mouth-to-

mouth rescue breathing과 가습 압박을 동반하는 경우와 비교

했을 때 덜 효과 이었다. 이는 소아에서 asphyxia로 인한

심정지가 많기 때문이다.

소아 심폐소생술을 잘 하기 해서는 다음과 같은 체계

인 평가가 필요하다.

Systematic approach to the seriously ill child

1.1 Initial impression

1) Consciousness - level of consciousness (unresponsive,

irritable, alert)

2) Breathing - increased work of breathing, absent or de-

creased respiratory effort

3) color - abnormal skin color (cyanosis, pallor, mottling)

1.2 Evaluate

1) Primary assessment: A rapid ABCDE approach (airway,

breathing, circulation, disability, exposure) to evaluate

respiratory, cardiac, and neurologic function, this step

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Fig. 1. Pediatric BLS algorithm.

김진태：소아를 한 심폐소생술

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Fig. 3. PALS bradycardiac algorith.

includes assessment of V/S and pulse oximeter

2) Secondary assessment: a focused medical history and

focused P/E

3) Diagnostic test:

1.3 indentify

1) Respiratory

　　 ㆍupper airway obstruction

　　ㆍlower airway obstruction

　　ㆍlung tissue disease

　　ㆍdisordered control of breathing

　 　 severity 에 따라 respiratory distress 혹은 failure

2) Circulatory

　 　ㆍhypovolemic shock

　 　ㆍdistributive shock

　 　ㆍcardiogenic shock

　　 ㆍobstructive shock

severity에 따라 compensated shock 혹은 hypotensive shock

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Fig. 4. PALS tachycardia algorithm.

성공 인 심폐 소생술을 해서는 효과 인 resuscitation

team dynamics가 요구되는데 다음과 같다.

Eight elements of effective team dynamics

1) Closed-loop communication

2) Clear messages

3) Clear roles and responsibilities

4) Knowing one’s limitations

5) Knowledge sharing

6) Constructive intervention

7) Reevaluation and summarizing

8) Mutual respect

PALS pulseless arrest algorithm, PALS bradycardia algo-

rithm, PALS tachycardia algorithm, PALS 약제를 Fig. 2, 3, 4

와 Table 2에 정리하 다. 성공 인 소아 심폐소생술을 하

기 해서는 상기 표와 algorithm을 숙지하고 평상시 교육과

훈련이 필요하다. 한 수술장내에서 심폐소생술은 일반 상

황과 다른 면이 있으므로 이에 한 이해가 필요하겠다.

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Table 2. 소아 심폐소생술 시 약제

참 고 문 헌

1. Berg MD, Schexnayder SM, Chameides L, Terry M, Donoghue

A, Hickey RW, Berg RA, Sutton RM, Hazinski MF. Part 13:

pediatric basic life support: 2010 American Heart Association

Guidelines for Cardiopulmonary Resuscitation and Emergency

Cardiovascular Care. Circulation 2010; 122(18 Suppl 3): S862-75.

2. Kleinman ME, Chameides L, Schexnayder SM, Samson RA,

Hazinski MF, Atkins DL, Berg MD, de Caen AR, Fink EL, Freid

EB, Hickey RW, Marino BS, Nadkarni VM, Proctor LT, Qureshi

FA, Sartorelli K, Topjian A, van der Jagt EW, Zaritsky AL. Part

14: pediatric advanced life support: 2010 American Heart

Association Guidelines for Cardiopulmonary Resuscitation and

Emergency Cardiovascular Care. Circulation 2010; 122(18 Suppl

3): S876-908.