Application of Ultrasound-guided Caudal Block:

Anesthesia in Pediatric Percutaneous Nephrolithotomy

Miao Yang, Hua Fang, Chong Liu and Fang-Xiang Zhang

Department of Anesthesiology, Guizhou Province People’s Hospital, Guiyang 550002, China

Corresponding author

Keywords: Ultrasound, Anesthesia, Caudal, Percutaneous Nephrolithotomy, Child.

Abstract: Objective: Evaluation of ultrasound-guided caudal block anesthesia in pediatric percutaneous nephrolithotomy.

Methods: Fifty children undergoing percutaneous nephrolithotomy were equally and randomly divided into

general anesthesia group (Group G) and ultrasound-guided caudal block combined with general anesthesia

group (Group C). The recovery time, emergence agitation and postoperative complications of the two groups

were observed. The children in Group G received general anesthesia with tracheal intubation, and the children

in Group C received tracheal intubation general anesthesia after caudal block. The consumption of

intraoperative opioids was compared, the postoperative recovery time, emergence agitation and early

postoperative pain score were observed, and the postoperative complications were recorded. Results: The

number of opioid analgesics in Group C was less than that in Group G (P <0.05). Recovery time in Group C

was shorter than that in Group G, and CHIPPS score in Group C was less than Group G in PACU (P <0.05).

The incidence of emergence agitation in Group C was significantly less than that in Group G (P <0.05). The

incidence of nausea and vomiting in Group C was significantly less than those in Group G (P <0.05).

Conclusions: Ultrasound-guided caudal block can be safely used in pediatric percutaneous nephrolithotomy.

Caudal block can reduce the dosage of opioid analgesics, improves the quality of recovery and the effect of

postoperative analgesia. It is easy to operate and has fewer complications.

1 INTRODUCTION

Urinary calculus is a common and frequently-

occurring disease in urology, while urinary calculus

in children accounts for 2 ~ 3% of total urolithiasis

(Castagnetti 2010). Studies have pointed out that

kidney stones disease has been increasing at all ages

in recent years, which leads to an increasing number

of patients needing corresponding surgical treatment

(Zeng 2018). With the development of urology

endoscopy, most children’s upper urinary tract stones

are treated by endoscopy, with the characteristics of

less injury, high success rate and fewer complications

(Hong 2018). Children need general anesthesia

because it is hard for them to cooperate during

operation, and combined caudal block anesthesia is

gradually paid attention to because of the advantages

of a small amount of general anesthetic, quick

recovery after an operation and so on. Ultrasound-

guided caudal block is simple and safe, giving

attention to both surgical anesthesia and

postoperative analgesia, and has been gradually used

in pediatric surgery (Ecoffey 2010). In this study,

ultrasound-guided caudal block combined with

general anesthesia was used in pediatric percutaneous

nephrolithotomy and compared with general

anesthesia with tracheal intubation alone, and the

recovery time, restlessness during recovery and early

postoperative pain were observed, which remained a

reference for clinical practice.

2 MATERIALS AND METHODS

2.1 General Information

This study was approved by the Medical Ethics

Committee of our hospital, and informed consent was

signed with the parents or legal guardians of the

children. From December 2019 to March 2021, 50

children undergoing elective percutaneous

nephrolithotomy in our hospital were selected, all of

whom were with unilateral kidney calculi, 32 males

and 18 females, aged 3-6 years, with ASA I or II. The

Yang, M., Fang, H., Liu, C. and Zhang, F.

Application of Ultrasound-guided Caudal Block: Anesthesia in Pediatric Percutaneous Nephrolithotomy.

DOI: 10.5220/0011212800003444

In Proceedings of the 2nd Conference on Artiﬁcial Intelligence and Healthcare (CAIH 2021), pages 157-161

ISBN: 978-989-758-594-4

 2022 by SCITEPRESS – Science and Technology Publications, Lda. All rights reser ved

157

blood routine and coagulation function were normal

before an operation, and there was no obvious

abnormality in liver and kidney function, no obvious

oropharynx, head and neck deformity or activity

disorder, and no diseases of the central nervous

system and blood system. There was no skin infection

or sacrum deformity in the sacrococcygeal region.

Children were randomly divided into general

anesthesia group (Group G) and ultrasound-guided

caudal block combined general anesthesia group

(Group C), with 25 cases in each group.

2.2 Methods

Children were routinely fasted and forbidden to drink

before surgery, and dexmedetomidine was dripped

intranasally at 1 ug/kg, alternately dripped into

bilateral nostrils, and gently rubbed the nasal wings

on both sides for 2 ~ 3 times. After entering the

operating room, the peripheral venous access was

opened, oxygen was inhaled with a conventional

mask, HR, BP, ECG and SpO2 were monitored, and

the corresponding type of endotracheal tube was

selected according to the age. In Group C, the

children were given ultrasound-guided caudal block

anesthesia, and the children were in the left lateral

position. After routine disinfection and towel laying,

the local anatomical structure of sacral hiatus was

observed with a 10 ~ 15 MHz linear array probe using

a color Doppler ultrasound instrument (GE Venue

50). The probe was placed in a sterile plastic sleeve,

perpendicular to the long axis of the body (cross-

section), and gradually moved upward from the

tailbone until a typical sacral hiatus image appeared

(Fig. 1). The puncture needle was inserted at the

midpoint of the probe using the out-of-plane

technique. After a sense of breakthrough appeared or

when the cross-section of the needle shaft in the sacral

hiatus was seen under ultrasound, the bloodless or

cerebrospinal fluid was pumped back, and then 0.2%

ropivacaine was injected 1ml/kg (Wang 2015).

During caudal solution injection, ultrasound showed

that the sacral hiatus was dilated (the sacrococcygeal

ligament was lifted), which indicated that the caudal

solution was injected into the sacral hiatus.

Anesthesia intubation was performed after nerve

block took effect and no adverse reactions such as

local anesthetic poisoning or total spinal anesthesia

were confirmed.

Two groups of children were given an intravenous

injection of propofol medium/long-chain fat

emulsion injection 3 ~ 3.5 mg/kg, fentanyl citrate

injection 2 ug/kg and rocuronium bromide injection 1

mg/kg for anesthesia induction. After mechanical

ventilation with the Omeda anesthesia machine, the

operation was started, continuous monitoring of end

tidal carbon dioxide Pressure (P

) was

maintained at 35 ~ 45 mmHg. During the operation,

remifentanil hydrochloride was injected

intravenously for 5 ~ 10 ug kg

-1

, and sevoflurane

was inhaled for 2% ~ 3% to maintain anesthesia, with

an end-tidal concentration of 0.8 ~ 1.0 MAC. After

the operation, remifentanil hydrochloride and

sevoflurane were stopped, and the children were sent

to PACU after spontaneous breathing returned to

normal, swallowing and cough reflex became active,

and the endotracheal tube was pulled out, oxygen was

inhaled through the mask, and vital signs were stable.

Figure 1: Ultrasound image of sacral hiatus.

2.3 Observation Indicators

The dosage of opioid analgesics during the operation

was recorded in the two groups, and the recovery time

and the occurrence of restlessness during the recovery

period were observed. The recovery time was from

the end of operation to the time of pulling out the

endotracheal tube. After entering PACU, the agitation

was evaluated by five-point scale: 0: drowsiness,

wakefulness; 1: Quiet, sober and cooperative; 2:

Crying, need appeasement; 3: Crying and fidgeting

are serious, unable to comfort, but do not need

braking; 4: dysphoria, disorientation, need to press

and brake, 3 points or 4 points mean restlessness. 15

minutes after being sent to PACU, the postoperative

pain of children was evaluated by the CHIPPS

scoring method, and the behaviors such as crying,

facial expression, trunk posture, leg posture and

restlessness were scored. Each item was subdivided

into three levels, and the scores were recorded as 0, 1

and 2 points step by step, with a total score of 10

points. The higher the total score, the higher the

degree of pain. The CHIPPS score ≥ 4 points

suggested the need for joint analgesic drugs. The

postoperative complications such as nausea,

vomiting, hypoxemia, laryngeal spasm and reflux

aspiration were recorded. All operations were

performed in the same operating room, and all

children were graded by anesthesiologists in PACU.

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2.4 Statistical Analysis

Data were analyzed using the SPSS19.0 software

(SPSS Inc., Chicago, IL, USA). Data were presented

as mean ± standard deviation (SD). Comparisons

among multiple groups were performed using a one-

way analysis of variance. Data within groups were

analyzed using analysis of variance with repeated

measurements. P < 0.05 was considered statistically

significant.

3 RESULTS

3.1 Comparison of General Data of

Children between the Two Groups

There is no significant difference in sex composition,

age, body weight and operation time between the two

groups (P >0.05), as shown in Table 1.

Table 1: Comparison of general information between two groups.

Group C (n=25) Group G (n=25)

Gender (Male/Female) 15/10 17/8

Age (years) 4.2±2.5 4.5±2.7

Body mass (kg) 15.8±3.6 16.3±4.2

Operation time (min) 82.5±30.1 96.3±37.4

3.2 Comparison of the Number of

Opioid Analgesics Used in the

Operation between the Two Groups

The amount of opioid analgesics used in the operation

of Group C is less than that in Group G, and the

difference is statistically significant (P <0.05), as

shown in table 2.

Table 2. Comparison of consumption of intraoperative opioids between two groups

Group C (n=25) Group G (n=25)

Remifentanil (ug) 126.5±31.8* 224.6±47.2

Fentanyl (ug/kg) 2.5±0.3* 3.4±0.7

Compared with Group G: *P <0.05.

3.3 Comparison of Recovery Time and

Postoperative CHIPPS Score

between the Two Groups

The recovery time in Group C is shorter than that in

Group G, and the CHIPPS score in Group C is smaller

than that in Group G, the difference is statistically

significant (P <0.05), as shown in table 3.

Table 3. Comparison of recovery time and CHIPPS scores between two groups.

Group C (n=25) Group G (n=25)

Awaking time (min) 10.3±4.5* 16.7±5.2

CHIPPS score (points) 2.5±0.7* 4.3±1.1

Compared with Group G: *P <0.05.

3.4 Comparison of Restlessness and

Postoperative Complications

between the Two Groups

The children in Group C were mostly quiet after

tracheal extubation, and the incidence of restlessness

in Group C was significantly less than that in Group

G (P <0.05), and the incidence of nausea and

vomiting in Group C was less than that in Group G (P

<0.05). There was no hypoxemia, laryngospasm and

reflux aspiration in both groups, as shown in table 4.

Table 4: Comparison of emergence agitation and complication between two groups.

Group C (n=25) Group G (n=25)

Nausea and Vomiting 2 (8.0)* 5 (20.0)

emergence agitation 3 (12.0)* 12 (48.0)

Compared with Group G: *P <0.05.

. .

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159

4 DISCUSSION

Caudal block is commonly used in children’s inguinal

region surgery, urinary system surgery and lower limb

surgery, and it is combined with general anesthesia in

clinical practice. The anesthesia effect is exact, which can

reduce the number of general anesthetics during operation,

exert ideal muscle relaxation and analgesic effect,

effectively block the stress response induced by surgical

stimulation, reduce the use of opioid analgesics after the

operation, prolong the postoperative analgesia time,

promote postoperative recovery and further reduce the

average hospitalization days (Schloss 2015). Conventional

caudal block is a safe method, complications may be

observed especially in children. Complications such as

subcutaneous and intraosseous injection, local anesthetic

toxicity or spinal anesthesia are related to inaccurate

placement of the puncture needle (Afshan 1996). With the

improvement of high-resolution portable ultrasound

equipment and probe technology, ultrasound technology

has been more and more used in nerve block anesthesia,

which broadens the role of ultrasound in clinical anesthesia.

Ultrasound-guided caudal insert can see the sacral hiatus,

sacrococcygeal ligament and sacral lumen, and can observe

the liquid flow produced by the injected local anesthetic

drug in the sacral lumen in real-time. The sensitivity and

specificity of ultrasonic monitoring of the correct position

of puncture needle during ultrasound-guided caudal block

are 96% and 100%, which is feasible and practical for

clinical application (Schwartz 2008). Because the structure

of sacral hiatus and local anesthetic injection can be

observed in real-time under ultrasound, the drug injection

position can be accurately judged, the puncture difficulty

can be reduced, and the success rate of blocking can be

improved.

In this study, 0.2% ropivacaine was used for sacral

canal block, which had little toxicity, no local

anesthetic poisoning reaction or total spinal

anesthesia, and produced a good anesthetic effect.

The recovery time of Group C was shorter than that

of Group G and the CHIPPS score after PACU was

lower than that of Group G which indicated that the

sacral canal block under ultrasound guidance was

effective and the circulation was stable, which

reduced the dosage of opioid analgesics during

operation, effectively shortened the recovery time of

children, and provided perfect postoperative

analgesia, which was beneficial to rapid recovery and

early postoperative pain relief.

Emergence agitation refers to a mental state in

which children’s consciousness and behavior are

separated during the awakening period after general

anesthesia, which is characterized by stubbornness,

irritability and inability to comfort, even crying,

hands and feet moving and disorientation, etc., and it

is impossible to identify familiar people or things in

the past (Mihara 2015, Hijikate 2016). The incidence

of restlessness during the awakening period is mainly

related to factors such as operation type, unfamiliar

environment, urinary catheter, quick awakening after

anesthesia and postoperative pain degree (Kim 2013).

In this study, the incidence of emergence agitation in

Group C was significantly lower than that in Group

G. It is considered that caudal block can reduce the

stimulation of urinary catheter, improve the analgesia

and prolong the postoperative analgesia time, thus

reducing the circulation fluctuation caused by general

anesthesia drugs and pain induced emergence

agitation and reducing the incidence of nausea and

vomiting. Postoperative canal block has a good long-

term analgesic effect, which also has a good effect on

the operation and psychological recovery of children,

and improves the satisfaction of their families to the

operation, thus increasing the safety factor of

anesthesia (Wang 2015).

Our study has several obvious limitations. It may

be difficult to display the needle using the out-of-

plane technique in some children. We did not have a

comparative group with conventional caudal block,

so we cannot comment on the efficiency and success

rate of placement using ultrasound-guidance. In

addition, the incidence of complications may not be

correctly determined in groups with small sample

size. Therefore, studies should be conducted on

groups with larger sample sizes. Finally, this study

did not compare the analgesic effect and duration of

local anesthetics with different concentrations.

5 CONCLUSIONS

Ultrasound-guided caudal insert can see the sacral

hiatus, sacrococcygeal ligament and sacral lumen,

and can observe the liquid flow produced by the

injected local anesthetic drug in the sacral lumen in

real-time. Ultrasound-guided caudal block can

produce a good anesthetic effect. Compared with

general anesthesia alone, it reduces the dosage of

opioid analgesics, improves the quality of anesthesia

recovery and provides perfect postoperative

analgesia. Ultrasound-guided canal block in children

can achieve accurate positioning, reduce puncture

difficulty and the complications, improve the success

rate of a block. It is convenient to operate, has few

complications, is safe and effective, is satisfactory to

parents and children, and is worthy of clinical

application.

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ACKNOWLEDGMENTS

Funding

This research was supported by the Foundation of

Science and Technology Department of Guizhou

Province (Qiankehe LH zi [2014]7027). and the

Youth Foundation of Guizhou Provincial People’s

Hospital (No. GZSYQN [2019]03). The funders had

no role in study design, data collection and analysis,

decision to publish, or preparation of the manuscript.

Availability of Data and Materials

The datasets used and analyzed during the current

study are available from the corresponding author on

reasonable request.

Declarations

Consent for Publication

Not applicable.

Competing Interests

All authors declare no conflicts of interest

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