Keywords
single-lung ventilation - thoracoscopy - children - lung resection - pediatric surgery
Introduction
Video-assisted thoracoscopic surgery (VATS) has gained wide acceptance in pediatric
thoracic surgery.[1]
[2]
[3]
[4]
[5]
[6] Numerous studies have demonstrated advantages of VATS versus conventional surgery,
such as lower postoperative pain, lower morbidity, faster recovery, superior cosmetic
results, and significantly less musculoskeletal sequelae.[1]
[2]
[3]
[7] Safety and efficacy of VATS in children have also been confirmed.[1]
[4]
[8]
[9]
Ipsilateral pulmonary ventilation might jeopardize the success of VATS due to poor
surgical exposure and might result in conversion to open surgery. Therefore, single-lung
ventilation (SLV) has been introduced to improve the feasibility of VATS. Various
SLV techniques have been assessed for adult patients,[10]
[11]
[12]
[13]
[14]
[15] and several studies have confirmed the feasibility and safety of SLV in VATS in
neonates and children.[3]
[4]
[16]
[17]
However, the indications for SLV in infants and children have not been clearly determined
yet,[18]
[19] and the role of SLV in thoracoscopic lung resection remains to be clarified. SLV
has been postulated to be absolutely indicated when the nondiseased lung must be protected from ipsilateral lung pathology,
such as, hemorrhage, infection, or spillage of tumor cells. Historically, VATS was
considered to be an absolute indication for SLV to provide surgical exposure in adult patients.[10]
[12]
[13]
[14] More recently, conventional double-lung ventilation (DLV) has proven to be efficient
as well, so that now VATS is considered to be a relative indication for SLV.[2]
[3]
Herein, we report our experience with SLV and DLV in a consecutive series of pediatric
patients, who underwent thoracoscopic lung resection with regard to safety, effectiveness,
and outcome. We hypothesized that the feasibility of SLV is excellent, but that DLV
in selected patients undergoing lung resection leads to similar results.
Patients and Methods
Patients
The study was approved by the Institutional Review Board (approval number: 995–2011).
Written informed consent was obtained from all patients/guardians for anonymized data
analysis.
We reviewed the medical records of all consecutive pediatric patients, who underwent
lung resection at our tertiary referral center during an almost 11-year period (January
2000 to November 2010). Demographical data, type of ventilation, localization, and
the extent of lung resection were analyzed. End points of the study were conversion
rate of VATS and reasons for conversion, duration of postoperative ventilation, and
intra- and postoperative complications, such as, atelectasis or pneumonia.
Atelectasis was defined by sharply lined areas of volume–decreased, radio-opaque lung
fields on chest X-ray. Pneumonia was defined by opacity of lung fields requiring antibiotic
therapy due to symptoms, such as, fever, and associated laboratory findings.[20] The diagnosis of atelectasis, pneumonia, and/or other pulmonary pathology was established
by a pediatric radiologist.
All lesions were preoperatively evaluated by computed tomography or magnetic resonance
imaging. SLV was mainly chosen for reasons of surgical exposure in those cases where
the pulmonary lesion was located in the upper, middle, and/or central lung. Patients
with a lesion in the lower lobe and those who underwent atypical resections were preferably
operated using DLV. The selection criteria for SLV are summarized in [Table 1].
Table 1
Preference for Single-Lung Ventilation Based on the Following Standardized Selection
Criteria
|
Selection Criterion
|
|
|
Patient's weight
|
≥2000 g
|
|
Patient's cardiorespiratory status
|
No major cardiac anomaly
No cardiac medication
No primary dependence on mechanical ventilator
No pathology of the contralateral lung
|
|
Location of pulmonary lesion
|
Upper lobe
Middle lobe
Central lung (all lobes)
|
|
Type of lung pathology
|
Infection
Tumor
|
Anesthesiological Approach
All operations were performed under general anesthesia. Midazolam was given as an
oral premedication 20 minutes prior to anesthesia induction. After intravenous induction
with propofol, fentanyl, and rocuronium, patients were intubated endotracheally and
ventilated mechanically with sevoflurane in oxygen and air.
SLV was achieved by fiberoptic bronchoscopic guidance using a tracheal intubation
fiberscope (Karl Storz, Tuttlingen, Germany) and three different age-adapted techniques
with either a narrow 2.2-mm insertion tube (LF-P, Olympus, Tokyo, Japan) or a 3.1-mm
insertion tube (LF-DP, Olympus, Tokyo, Japan). Endobronchial intubation using a conventional
single-lumen endotracheal tube (SLET) that was inserted into the main-stem bronchus
of the dependent lung was performed in patients aged 6 years or younger ([Table 2]). In children aged 6 to 12 years, a Univent tube (Fuji Systems Corporation, Tokyo,
Japan) was used and the attached bronchus blocker was blocked in the main-stem bronchus
of the dependent lung. Children aged 12 years or older were intubated with either
a Univent tube, a double-lumen endotracheal tube (DLET; Broncho-Cath; Mallinckrodt
Medical, Athlone, Ireland), or an Arndt endobronchial blocker (Cook Medical, Limerick,
Ireland). Univent tubes and DLET were changed to SLET postoperatively when prolonged
mechanical ventilation was required.
Table 2
Age-Adapted Tube Selection for Single-Lung Ventilation in 52 Pediatric Patients Undergoing
Thoracoscopic Lung Resection
|
Age, y
|
SLET,
ID in mm
|
Univent Tube, ID in mm
|
Endobronchial
Blocker, Fr
|
DLET, Fr
|
|
≤ 6
|
3.5–5.5
|
–
|
–
|
–
|
|
6–12
|
–
|
3.5–4.5
|
–
|
–
|
|
≥ 12
|
–
|
4.5–7.0
|
9
|
26–35
|
Note: Children of the same age may significantly vary in overall size and the dimensions
of the airway.[1] Larger DLETs may safely be used in teenagers.
SLET, single-lumen endotracheal tube; ID, internal diameter; Fr, French size; DLET,
double-lumen endotracheal tube.
The respiratory rate was increased up to 30 to 50 breaths per minute, and tidal volume
was decreased to improve the surgical visualization during artificial pneumothorax.
Standard perioperative monitoring included pulse oximetry, electrocardiogram, end-tidal
CO2 measurement, inhaled volatile agent concentration, invasive blood pressure measurement,
arterial blood gas measurement, and temperature. Extended monitoring was indicated
if hemodynamic alterations were anticipated.
Surgical Approach
All thoracoscopic interventions were performed with the patient in a lateral decubitus
position and prepared for open thoracotomy should this have proved necessary. Procedures
were performed using reusable instruments (Karl Storz, Tuttlingen, Germany). A video
thoracoscope was inserted to visualize the operative field. Carbon dioxide was insufflated
to a maximum pressure of 5 to 8 mm Hg at a maximum flow rate of 5 L/min. To prevent
CO2-overinsufflation, insufflators specifically suitable for neonates were used, delivering
CO2 in small controlled puffs, allowing a better adjustment of the intrathoracic pressure.
Three to five valved ports (3.5 to 10 mm) were inserted depending on the localization
of the pathology. Instruments and surgical technique varied depending on the effected
lobe and type of pathology. Lobectomy and segmentectomy were performed using Endostapler
(Ethicon, Norderstedt, Germany) or LigaSure Vessel Sealing System (Valleylab, Boulder,
Colorado, United States), respectively. Atypical lung resections were performed using
Endoloop Ligatures (Ethicon, Norderstedt, Germany) or Endostapler (Ethicon, Norderstedt,
Germany).
Statistical Analysis
Data were quoted as median and interquartile ranges. The statistical software package
SPSS version 18 (SPSS, Inc., Chicago, Illinois) was used. Intergroup comparison was
assessed using unpaired t test, Mann-Whitney U tests, or chi-square test where appropriate. A p value of less than 0.05 was considered significant.
Results
During the study period, 114 consecutive patients (58 female and 56 male; ratio 1.04:1)
with a mean age of 7.1 years (3 days to 18.1 years) underwent thoracoscopic lung resection.
The mean body weight and height were 27 kg (2 to 82 kg) and 114.3 cm (39 to 213 cm),
respectively ([Table 3]). Therapeutic lung resection was performed for congenital cystic adenomatoid malformation
(n = 9), bronchopulmonary sequestration (n = 10), bronchiectasis (n = 10), bronchogenic cyst (n = 7), congenital lobar emphysema (n = 18), and malignancy (e.g., bronchial carcinoid; n = 9).
Table 3
Demographical Data of 114 Infants and Children Who Underwent Thoracoscopic Lung Resection
|
DLV (n = 62)
|
SLV (n = 52)
|
p Value
|
|
Age
|
5.8 y (21 d–17.8 y)
|
11.4 y (3 d–18.1 y)
|
0.013
|
|
Gender
|
47 female, 15 male
|
11 female, 41 male
|
<0.01
|
|
Weight, kg
|
21.5 (3–82)
|
33.6 (2–74)
|
0.004
|
|
Height, cm
|
104.6 (47–188)
|
125.9 (39–213)
|
0.01
|
DLV, double-lung ventilation; SLV, single-lung ventilation.
Atypical resection was performed for diagnostic purposes (n = 35) or for excision of pulmonary metastasis (n = 16). Resections were performed for lesions located in the upper lobe in 43 patients
(37.7%), middle lobe in 8 patients (7.0%), lower lobe in 53 patients (46.5%), and
others in 10 patients (8.8%) ([Table 4]).
Table 4
Localization of Thoracoscopic Lung Resection in 114 Pediatric Patients
|
Site of Resection
|
Number of Patients
Using DLV
(n = 62), n (%)
|
Number of Patients
Using SLV
(n = 52), n (%)
|
p Value
|
|
Upper lobe
|
19 (30.6)
|
24 (46.2)
|
n.s.
|
|
Middle lobe
|
4 (6.5)
|
4 (7.7)
|
n.s.
|
|
Lower lobe
|
31 (50)
|
22 (42.3)
|
n.s.
|
|
Others[a]
|
8 (12.9)
|
2 (3.8)
|
n.s.
|
Note: No statistical analysis was performed due to differences in patient characteristics.
a Bilateral lower lobe (n = 1), upper + lower lobe (n = 1), middle + upper lobe (n = 1), middle + lower lobe (n = 1), upper lobe + mediastinum (n = 5), lower lobe + diaphragm (n = 1).
DLV, double-lung ventilation; SLV, single-lung ventilation.
Of 114 procedures, 62 procedures (54.4%) were performed using conventional DLV, whereas
52 procedures (45.6%) were performed using SLV ([Table 3]).
Segmentectomy or lobectomy was performed in 61 patients (54%), of whom, 25 patients
(41%) underwent DLV and 36 patients (59%) underwent SLV. Atypical lung resections
were performed in 53 patients (46%), of whom, 37 patients (70%) received DLV and 16
patients (30%) received SLV.
In the group of patients who underwent SLV, there were 10 of 52 patients (19.2%) below
1 year of age and 13 of 52 patients (25%) below 10 kg body weight.
In the group of patients below 1 year of age who underwent SLV, the operative diagnoses
were congenital cystic adenoid malformations or pulmonary sequestration (n = 5), bronchogenic cyst (n = 2), congenital lobar emphysema, bronchiectasis, or interstitial lung disease (n = 3). In nine of these patients, a lobectomy was performed and one patient received
an atypical lung resection.
The conversion rate in DLV patients was 5 of 62 (8.1%). These thoracoscopic operations
were converted due to exposure difficulties (n = 3), insufficient ventilation (n = 1), and technical problems (n = 1) ([Fig. 1]). Seven of 52 SLV procedures (6.1%) were converted to an open procedure due to exposure
difficulties (n = 6) and bleeding (n = 1). Two of these patients were infants, and both had to be converted due to exposure
difficulties. However, none of the infants were converted for hemodynamic pertubation
induced by VATS. The conversion rate was not significantly different between the groups
(p = 0.53).
Figure 1 Conversion rate of VATS to open thoracotomy and incidence of postoperative atelectasis
and pneumonia in 114 pediatric patients undergoing thoracoscopic lung resection using
DLV (n = 62) or SLV (n = 52). VATS, video-assisted thoracoscopic surgery; DLV, double-lung ventilation;
SLV, single-lung ventilation, n.s., not significant.
At the end of the operation, 31 DLV patients (50%) were immediately extubated, whereas
21 (33.9%) remained ventilated up to 24 hours postoperatively, and 10 patients (16.1%)
required more than 24 hours of ventilation ([Fig. 2]). Conversely, 18 SLV patients (34.6%) were extubated immediately after surgery,
27 (51.9%) were extubated within 24 hours, and 7 (13.5%) were extubated after 24 hours,
postoperatively. There were no statistical differences in the duration of postoperative
ventilation between the two groups ([Fig. 2]).
Figure 2 Postoperative extubation in 114 pediatric patients undergoing thoracoscopic lung
resection. VATS, video-assisted thoracoscopic surgery; DLV, double-lung ventilation;
SLV, single-lung ventilation, n.s., not significant.
The mean stay on the intensive care unit after DLV was 4 days (0 to 53 days) days
compared with 3.3 days (0 to 64 days) after SLV (p = 0.52). Twenty-two patients (35.5%) developed atelectasis after DLV. In all of these
patients, atelectasis resolved spontaneously without intervention ([Fig. 1]). Following SLV, atelectasis developed in 13 patients (25%), of whom, one patient
required bronchoscopic intervention. The incidence of atelectasis was not significantly
different between the groups (p = 0.32). Postoperatively, no pneumonia, cardiorespiratory event, or bleeding requiring
transfusion occurred ([Fig. 1]). There was no perioperative mortality.
Discussion
Single-lung ventilation during VATS is recommended to create space for adequate visualization,
exposure, and dissection while oxygenation is maintained.[12]
[15]
[18]
[21] Rothenberg postulated that most children can tolerate SLV without significant respiratory
compromise during major thoracoscopic procedures.[8]
[9] Recently, a study from our institution demonstrated that SLV is feasible and efficient
for a broad spectrum of thoracoscopic procedures in children and adolescents and has
a low complication rate.[17] On the contrary, McGahren et al reported that thoracoscopic surgery was successfully
performed under DLV in 44 of 68 children. Infants and small children often did not
tolerate SLV.[22] As a consequence, the feasibility of SLV in infants and small children may be limited
and SLV might not be necessary for every thoracoscopic operation.
In this series, more than half of the thoracoscopic lung resections were performed
using DLV. SLV was more frequently applied when patients were older and in cases in
whom the region of interest was located in the upper, middle, and/or central lung.
Conventional DLV was preferred in cases where the lesion was located in the lower
lobe. In addition, SLV was performed more frequently in extended lung resections,
whereas DLV was used more often in atypical resections.
Using this policy, the conversion rate was low and the incidence of complications
was similar in both groups. We confirmed an excellent feasibility of VATS, not only
in SLV patients, but also in DLV patients. The incidence of problems of visualization
and exposure leading to conversion was not significantly different between the groups.
Therefore, a recommendation for routine use of SLV in all infants and children undergoing
thoracoscopic lung resection cannot be given. Minimally invasive lung resection with
DLV may achieve excellent results in a selected group of patients. Nevertheless, the
feasibility of SLV was excellent without clinically relevant perioperative complications
in our series.
It has been reported that compression of the dependent lung in the lateral decubitus
position may cause atelectasis in children. In contrast to adult patients, this is
due to several specific factors such as ventilation/perfusion mismatch, reduced hydrostatic
pressure gradient between the nondependent and dependent lungs, or the more compliant
chest wall.[18]
[23] All thoracoscopic procedures in this study were performed with the patient in a
lateral decubitus position, which may explain the high incidence of atelectasis after
both ventilation strategies. However, bronchoscopic intervention was necessary only
in one child of our series and there was no postoperative pneumonia.
A drawback of our study is that the groups of patients who underwent SLV and DLV were
not comparable. SLV patients were significantly older and had a higher weight, and
the types of operations were not equally distributed.
Conclusions
This study evaluated safety, effectiveness, and outcome of SLV and DLV in pediatric
patients who underwent lung resection. Our data suggest that both SLV and DLV can
be safely performed without respiratory compromise or surgical complication, when
specific selection criteria are applied. We advocate a differentiated use of both
strategies on infants and children undergoing thoracoscopic lung resection.
