Tomasz Dygas, Stanisław Nowak, Tadeusz Biegański
Selective bronchial suctioning in the intubated neonate: how selective is it?
IInd Dept of Neonatological Intensive Therapy, Dept of Radiology "B", "Polish Mother Center" Institute, Łódź, Poland
We have analysed 96 chest X-rays of twenty-six cadaver neonates in whom contrast - prefilled suction catheters were introduced in five different body positions. We have expected to find an optimal position that could facilitate selective suctioning of main stem bronchi. We have noted angles between the trachea and bronchi and catheters'placement. Student's t-test was used for statistical analysis of the angles of divergence and Chi² and Fisher exact tests for determining of relationship between head vs. body position and placement of the catheter.
We have found that rotation of the head and/or changing of the body position significantly (p<0.05) increased the angle of divergence or main stem bronchi from the trachea. Surprisingly, only the left lateral decubitus position statistically increased number of the right bronchical catheterisations. Contrary to the previous findings, other positions were not related to right or left bronchical catheterisation.
We conclude that the position of the catheter during suctioning is unpredictable and therefore, selective bronchical catheterisation may not be possible in the neonatal intensive care.
During recent years one can observe a rapid development of therapeutic methods in intensive neonatal care. Many procedures, proven efficient in adult patients are being modified to the use in neonatology practice. Adaptation processes, specificity of homeostatic mechanisms and different anatomical conditions in the neonate pose the need for meticulous evaluation of these procedures.
One of the canons of physiotherapy in intubated patients is a selective catheterization of the right or left bronchus. Published reports suggest that the right bronchus catheterization is facilitated by the rotation of the head to the left or by placing the patient in the right lateral decubitus position. The opposite bronchus should be catheterized by the action of gravity, as it lies inferiorly. This can also be achieved by the rotation of the head to the right or by placing the patient in the left lateral decubitus position. This method is specially avocated in patients with unilateral atelectasis. There are no many publications, however, proving the usefullness of this method in neonates [1, 2, 3, 4, 5, 6, 7, 8, 9]. These reports are several years old, when the neonates population and the available medical equipment differed significantly from the present times. The aim of the present study was to assess the value of selective bronchial suctioning in intubated neonates.
After obtaining the permission from the local Ethical Committee the study was carried out from December 1995 to January 1997.
The study was performed on 23 dead neonates, previously artificially ventillated. Anomalies influencing the respiratory system anatomy (pneumothorax, diaphragmatic hernia, airways strictures etc.) were the criteria of exclusion from the study. All neonates, before their death, were treated according to typical medical procedures and were intubated pernasally (Portex Ltd, Great Britain). The size and the position of the tube in the upper airways were based on the commonly accepted rules .
Postmortem examination was carried out only when the parents did not express their objection.
Immediately after the death, before discarding the endotracheal tube, 5 X-rays were performed in different body positions (Figs. 1, 2, 3, 4 and 5):
– head rotation to the right
– head rotation to the left
right lateral decubitus position
left lateral decubitus position.
Fig. 1. Thoracic X-ray in prone position with the head in intermediate position. In 55% of cases the catheter was introduced to the right main bronchus.
Fig. 2. Thoracic X-ray in prone position with the head rotated to the right. In 75% of cases the catheter was introduced to the left main bronchus (p=0.054).
Fig. 3. Thoracic X-ray in prone position with the head in rotated to the left. In 71% of cases the catheter was introduced to the right main bronchus (p=0.173).
Fig. 4. Thoracic X-ray in left lateral decubitus position. According to the literature the catheter should enter the left main bronchus as the result of gravity force. In this position, however, the angle between RMB and trachea significantly increases, which resulted in 94% catheterization of the opposite (right), than intented, bronchus (p=0.03).
Fig. 5. Thoracic X-ray in right lateral decubitus position. The angle between LMB and trachea increases less than in the abovementioned situation. Catheterization of the left main bronchus was successful in 62.5% of cases (p=0.08).
The X-rays were taken in a separate room, with the aid of mobile apparatus. After the correct positioning of endotracheal tube a catheter (Unoplast, Denmark) prefilled with contrast medium (60% Uropoline) was inserted into its lumen. The size of the catheter depended on the size of the tube, according to the commonly accepted rules . On the basis of radiographs performed, the placement of the catheter tip was assessed and the angles of main bronchi deviation from the tracheal axis were measured. Statistical analysis was performed using Student's t-test for angles values and Chi² test for the assessement of selectivity of bronchial catheterization. Data do not fulfilling the criteria of abovementioned tests were analysed with the Fisher's exact test.
Demographic data of patients are presented in table I. From 115 radiographs, 19 were excluded from analysis for technical reasons. Differences between the angle of deviation from tracheal axis of the main bronchi in the intermediate head position were found. The increase of the angle value, depending on the patient's position was documented for the right main bronchus (RMB) and left main bronchus (LMB). These differences were statistically significant for RMB/trachea angle between intermediate head position and left lateral decubitus positIon or head rotation to the left; for LMB/trachea angle between intermediate head position and right lateral decubitus (Tab. III); for RMB/trachea angle between left lateral decubitus and prone position with the head rotation to the left; for LMB/trachea angle between right lateral decubitus and prone position with the head rotation to the right; for the angles of main bronchi/trachea angles in prone and lateral positions after head rotation to the left or right (Tab. IV). Only in prone position the head rotation to the right did not cause statistically significant change of the LMB/trachea angle as compared with the intermediate head position. In the remaining cases the change of position increased the trachea/bronchus angle, which could theoretically favorise the selective bronchial catheterization. The angles changes observed were almost identical as described by Fewell et al., where the radiographs were performed in living patients .
The comparison of actual results as compared with the anticipated ones (Tab. II) (anticipated results: the theoretical localization of the catheter tip implied by the position of the patient) revealed that in the intermediate position the RMB catheterization occurred in 55% of cases (12/22); in prone position with the head rotation to the left - in 71% (15/21) and in right lateral decubitus - in 37.5% of cases (6/16). The differences were not statistically significant. LMB catheterization was successful in 75% (15/20) of cases in the prone position with the head rotation to the right, in 6% (1/17) in the left lateral decubitus. In the latter group the frequency of the unintended catheterization of the opposite bronchus (RMB - 16/17 patients) was statistically significant.
Table I. Foetal age (weeks) and body weight
| ||Foetal age||Body weight|
Table II. The rate of success in introducing the catheter into the required bronchus
| ||Intermediate position||Right head turn||Left head turn||Right lateral decubitus||Left lateral decubitus|
|Number of patients||21||20||20||16||17|
Table III. Comparison of the tracheal/main bronchi angles in different body positions (the intermediate head position serves as a standard)
|Position||Intermediate||Left head turn||Intermediate||Right head turn||Intermediate||Left lateral||Intermediate||Right lateral|
|Angle (degr) mean||147||134||147||157||134||137||147||165||134||148|
|Standard deviation - SD||7.2||14.7||7.2||8.3||14.7||11.2||7.2||9.4||14.7||7.4
Table IV. Trachea/main bronchi angles in different body positions. Comparison of different positions
|Position||Right head turn||Right lateral||Left head turn||Left lateral||Right head turn||Left head turn||Right lateral||Left lateral|
|Angle (degr) mean||137||148||157||165||137||157||148||165|
Table V. The influence of the body position on the catheterization effect
|Number of patients||20||21||16||17|
* probability of catheterization of the opposite, to the intended, bronchus
Although the change of body position, from the intermediate one, increased the chance to the correct placement of the catheter tip, statistical analysis (Tab. III) revealed that only the left lateral decubitus position gives statistically greater chance for RMB catheterization (p=0.003). The chance to selective catheterization of the LMB in prone position with the head rotation to the right was assessed as borderline from the statistical point of view (p=0.054). No statistically significant differences were found among the remaining parameters analysed.
In patients requiring the support of basic vital functions, physiotherapy plays a very important role. This includes, among others, therapeutic measures such as the meticulous toilet of the upper airways, aimed at mobilization and suctioning out the secrections produced as the effect of the illness itself, irritation by endotracheal tube or suction catheters introduced too deeply into the bronchial tree. The importance of bronchial suctioning is undiscutable, as it diminishes the volume of bronchial secretions, restores the aeration of atelectatic pulmonary parenchyma, increasing blood oxygen saturation. Despite commonly accepted standards, however, it carries the risks of untoward effects. These include: ventillation depression, risk of infection, intensive pain, peripheral vascular flow impairment, intracranial pressure changes etc. Therapeutic procedures employed in the Intensive Therapy Unit are frequently painful for the patient and require analgesia. That is why the procedures which are not absolutely necessary for the patient's treatment should be eliminated. Selective bronchial suctioning proved to be efficient in adult patients. After introducing the catheter via the lumen of endotracheal tube (in patients with nasal intubation) and turning the head (the catheter tip is then directed to the opposite side) the chance to selective bronchial suctioning increases. Another hint is to place the patient in a lateral position: one can estimate that the gravity force will help to introduce the catheter into the bronchus ipsilateral to the side on which the patient is placed. In critically ill neonate, whose homeostasis is already profoundly disturbed, two elements are dangerous: changes of the body position and the deep insertion of the suctioning catheter. Both of them can provoke further untoward reactions. These doubts were the motivation to undertake a study assessing the relation of bronchial catheter localisation from the head and body position. The results presented limit the possibilities of this method: statistically significant difference ws demonstrated only for selective RMB catheterization and left lateral decubitus position of the patiet. During interpretation of the results it was found that the change in the body position maximally increases the trachea/main bronchi angles in left lateral decubitus. This may be caused by several factors: the neonate (specially pre-term born) thorax is relatively more elastic and, as such, more prone to deformation with the body position changes; the left sided heart position in the patient lying on the left side causes more marked (than in the right lateral position) displacement of tracheal bifurcation upwards, which increases the RMB/trachea angle. Currently employed suction catheters have a smaller diameter and are made of more plastic materials, than thicker and more rigid rubber catheters used previously, and are less traumatizing for the patient. On the other hand the new catheters more easily bend in the airways lumen which make the selective bronchial catheterization more difficult, if possible at all.
The change of body position or head rotation in neonates minimally influence the chance of selective bronchial catheterization. Only in the left lateral decubitus position the chance of right main bronchus catheterization signifantly increases.
Originally published in Anestezjologia Intensywna Terapia 31; (4), 233-236, 1999.
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