A randomized trial of suprasternal palpation to determine endotracheal tube position in neonates

Resuscitation 60 (2004) 297–302

A randomized trial of suprasternal palpation to determine endotracheal tube position in neonates Alok Jain, Neil N. Finer∗ , Saskia Hilton, Wade Rich Department of Pediatrics, Division of Neonatology, University of California San Diego Medical Center, 200 West Arbor Drive-8774, San Diego, CA 92103-8774, USA Received 17 September 2003; received in revised form 13 November 2003; accepted 13 November 2003

Abstract Objective: To compare suprasternal palpation, a previously described bedside technique, with standard chest radiography for correct positioning of the endotracheal tube (ETT) in newborn infants. Study design: A randomized single-blinded study in an academic medical center. Preterm and term newborn infants requiring intubation were eligible, provided that they had not had their initial chest roentgenogram (CXR). Infants were randomized to ETT palpation and non-adjustment (Controls), or to ETT palpation and adjustment (Treatment), following digital palpation of the ETT tip in the suprasternal notch. ETT position was considered correct when only the tip of the ETT was palpable in the suprasternal notch. ETT position by CXR was blindly assessed by an experienced pediatric radiologist. Results: Fifty-five infants were enrolled in the delivery room or neonatal intensive care unit. Correct tube placements improved from 48% pre-study to 85 and 93% in the Control and Treatment arms, respectively. The majority of incorrect estimations were that the ETT position using palpation was judged to be too low when it was, in fact, in correct position, as noted in 11 infants. ETT palpation had a 70% concordance with the position determined by CXR. No difficulties or complications were associated with the use of suprasternal palpation. Conclusions: Suprasternal palpation is a simple, safe, teachable, method of confirming ETT position in neonates when CXR is unavailable, and may especially helpful during neonatal resuscitation prior to surfactant administration. © 2003 Elsevier Ireland Ltd. All rights reserved. Keywords: Intubation; Chest roentgenogram; Neonatal resuscitation; Palpation

Resumo Objectivo: Comparar a palpação supraesternal, técnica de cabeceira conhecida, com a radiografia torácica clássica para avaliar o posicionamento correcto do tubo endotraqueal (ETT) na criança recém-nascida. Desenho do estudo: Estudo aleatorizado, com ocultação simples, num centro académico médico. Foram seleccionadas crianças prétermo e de termo com necessidade de entubação, desde que não tivessem realizado a sua radiografia torácica inicial (CXR). As crianças foram aleatorizadas para palpação ETT e não ajustamento (Controlos), ou para palpação ETT e ajustamento (Tratamento), após palpação da ponta do ETT no cavado supraesternal. A posição do ETT era considerada correcta quando só se palpou a ponta do ETT no cavado supraesternal. A posição do ETT no CXR foi avaliada de forma cega por um radiologista pediátrico experiente. Resultados: Foram inclu´ıdas 55 crianças na sala de parto da unidade de cuidados intensivos neonatais. O posicionamento correcto do tubo melhorou de 48% pré-estudo para 85 e 93% nos braços Controlo e Tratamento, respectivamente. A maioria das estimativas incorrectas porque a posição do ETT foi interpretada como muito baixa usando palpação quando, de facto, a sua posição era correcta, o que aconteceu em 11 crianças. A palpação do ETT era concordante em 70% com a posição determinada por CXR. Não se encontraram dificuldades ou complicações associadas à palpação supraesternal. Conclusões: A palpação supraesternal é um método simples, seguro e exequ´ıvel de confirmação da posição do ETT em recém-nascidos, quando o CXR não está dispon´ıvel, e pode ser particularmente útil durante a reanimação neonatal antes da administração de surfactante. © 2003 Elsevier Ireland Ltd. All rights reserved. Palavras chave: Intubação; Radiografia torácica; Reanimação neonatal; Palpação

∗ Corresponding author. Tel.: +1-619-543-3759; fax: +1-619-543-3812. E-mail address: [email protected] (N.N. Finer).

0300-9572/$ – see front matter © 2003 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.resuscitation.2003.11.010

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Resumen Objetivo: Comparar la palpación supraesternal, una técnica que se realiza al lado de la cama previamente descrita, con la radiograf´ıa de tórax estándar, para corregir la posición del tubo endotraqueal (ETT) en niños recién nacidos. Diseño del estudio: Un estudio randomizado, ciego en un centro médico académico. Fueron elegibles recién nacidos de pretérmino y de término que requirieran intubación, si no hab´ıan tenido aun su primera radiograf´ıa (CXR). Los niños fueron randomizados a palpación de ETT y a sin-ajustes(control), o a palpación ETT y ajuste(Tratamiento), después de la palpación de la punta del ETT por encima del manubrio esternal. La posición del ETT fue considerada correcta cuando solo la punta era palpable en el hueco supraesternal. La posición del ETT por CXR, fue evaluado en forma ciega por un radiólogo pediátrico experimentado. Resultados: 55 niños fueron enrolados en la sala de partos o en la unidad de cuidados intensivos neonatales. La correcta ubicación del ETT mejoró desde 48% en el preestudio a 85 y 93% en los grupos control y tratamiento respectivamente. La mayor´ıa de las estimaciones incorrectas fuero que la posición del ETT usando la palpación fue juzgada como muy baja cuando estaba, de hecho, en posición correcta, como se vio en 11 niños. La palpación del ETT tuvo una concordancia de 70% con la posición determinada por CXR. No se asociaron dificultades ni complicaciones con el uso de la palpación supraesternal. Conclusiones: La palpación supraesternal es un método simple, seguro y fácilmente enseñable que sirve para confirmar la posición del ETT en neonatos cuando no hay disponibilidad de CXR, y puede ser especialmente útil durante la resucitación neonatal antes de la administración de surfactante. © 2003 Elsevier Ireland Ltd. All rights reserved. Palabras clave: Intubación; Radiograf´ıa de tórax; Resucitación neonatal; Palpación

1. Introduction The practice of ETT tube palpation dates back to the time of first use of an endotracheal tube to resuscitate an infant by Dr. James Blundell, a British obstetrician in 1834, who noted “Artificial respiration should be diligently tried . . . by means of a tracheal pipe . . . afterwards feeling on the front of the neck whether the instrument is lying in the trachea or esophagus” [1]. Oral endotracheal intubation is a common means of supporting respiratory function in term and premature neonates. Prophylactic surfactant therapy administered via the endotracheal tube (ETT) in the delivery room (DR) reduces morbidity and mortality associated with Respiratory Distress Syndrome (RDS) [2]. A chest roentgenogram (CXR) to evaluate placement is not immediately available in the DR and clinical examination is unreliable in ascertaining depth of intubation [3]. The resulting blind administration of surfactant can be problematic resulting in unilateral deposition and airleaks [4]. In addition, ETT malposition is frequently noted on the initial CXR in neonates and has been reported to be in the range of 35–50% [5–7]. A number of methodologies to ascertain ETT position have been previously evaluated [8–11]. In 1975, Bednarek and Kuhns reported on a simple technique to confirm position using digital suprasternal palpation on neonates and one small infant [12]. Their palpation group had significantly more accurate ETT placements without any adverse effects, compared to those infants who had their ETT placed using standard weight-based criteria. In addition, this study reported significantly lower rates of complications such as atelectasis and pneumothorax with the use of palpation. There have been no subsequent prospective trials evaluating this technique, which is infrequently utilized in neonatal medicine.

We wished to reassess the potential benefit of ETT palpation technique in the surfactant era in a larger prospective randomized study.

2. Materials and methods This was a randomized single-blinded prospective trial of ETT palpation performed at UCSD Medical Center. The control group had tube insertion distance pre-determined by a nomogram based on birthweight [13]. The tube was then palpated but could not be moved prior to the confirming X-ray. Insertion distance was estimated by a weight nomogram in the Treatment group, then the palpation technique described below was performed to adjust the insertion distance prior to CXR. Enrollees included all infants requiring intubation in the DR or the NICU who received an initial CXR to evaluate ETT position. Patients were excluded in the presence of congenital malformations affecting the head or neck area. Patients were only studied once. The primary hypothesis was that palpation with repositioning would result in a higher percentage of correctly placed endotracheal tubes than palpation alone. 2.1. Palpation technique After ETT placement, the tip was gently palpated in the suprasternal notch with the index or little finger of the left hand while holding the body of the ETT with the fingers of the right hand. Tube position was recorded as being low when the body and not the tip was palpable, and too high when the tube was not palpable. Only when the tip of the ETT was palpable in the suprasternal notch was the position considered correct. In the treatment group the body of the ETT was moved up or down in 1/4 to 1/2 cm increments while the ETT tip was palpated with the index finger of

A. Jain et al. / Resuscitation 60 (2004) 297–302

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sitioning of the ETT was defined as >0.5 cm above the interclavicular midpoint (high placement), <1 cm above the carina (low placement, at the carina) or >0.5 cm into a mainstem bronchus (mainstem intubation). Correct position was defined as any position <0.5 cm above the interclavicular midpoint and >1 cm above the carina. 2.3. Randomization

Fig. 1. Landmarks for palpation. A line drawn through the medial heads of the clavicles corresponds internally to true midpoint of the trachea and this area approximates the suprasternal notch externally.

the left hand. The ETT tip was adjusted until the beveled edge was just palpable. Bednarek and Kuhns had previously shown that this tracheal midpoint corresponded externally to the suprasternal notch, and internally to a line drawn between the medial heads of the clavicles [12] (Fig. 1). The distance at the lip was recorded prior to re-securing the tube at the lip. After final positioning, the ETT position was determined as high, low or correct position by the physician performing palpation and a CXR obtained to confirm the placement. Patients in both groups had their ETT position changed if necessary, on the basis of their subsequent CXR, to achieve optimal placement. 2.2. Training All neonatal fellows were trained in the suprasternal palpation technique prior to the commencement of the study to ensure uniformity and correct technique. The trainees were considered competent when they could determine ETT position on more than three occasions rapidly and without evidence of discomfort or destabilization of the infant, including accidental extubation. A lockable ETT holder (SIMS, Irvine, CA) was used to minimize accidental changes in tube position. Tape was used in place of the holder in extremely preterm infants due to space considerations. Nurses were instructed to assure that the CXR was performed with the infant’s head in the neutral position. A pediatric radiologist blinded to randomization status reviewed the chest roentgenograms and for quality, head position, and tube position utilizing the criteria of Kuhns and Poznanski [5]. Data was collected for each patient on a standardized form that included baseline characteristics, location of intubation and interventions, time to obtaining the initial CXR, and the incidence of complications or death within 12 h of intubation. ETT position was classified as correct or suboptimal for purposes of statistical analysis. Suboptimal po-

Patients were block randomized in groups of six to either palpation alone (Control), or to palpation with the option of manipulation (Treatment). Randomization was performed using double-sealed envelopes, kept in a secure location in our NICU, which were opened prior to the delivery or intubation of a consented infant. We estimated that the rate of appropriately positioned endotracheal tube tips would increase from 48%, our actual pre-study experience using a weight based nomogram and pre-marked endotracheal tubes, to 85%, or a 77% increase in the number of successfully placed endotracheal tubes. Thus we estimated that we would need 25 patients per arm in order to have a power of 80% with an alpha of 0.05. Secondary endpoints included comparisons of rates of complications or death in the 12 h following the intubation, need for tube adjustment after the initial securing of the ETT, need for repeat CXRs to confirm ETT position after manipulation, and subgroup analysis for adequacy of tube placement in the <1500 and >1500 g weight groups. Data was analyzed using statistical software (Graphpad Instat v 3.01), and an unpaired t-test and Fishers exact test were used for direct comparisons between the Control and Treatment groups, a P value <0.05 being considered significant. The Human Subjects Committee of the UCSD Medical Center approved this study. Informed written consent was obtained from the parents or guardians prior to patient enrollment.

3. Results The study was carried out between August 2001 and May 2002. Fifty-five patients were randomized to either palpation alone (Control), or palpation and movement (Treatment). One patient had his ETT removed prior to CXR verification of position and only demographic data is recorded for this infant, leaving 27 infants per group. All CXRs were of suitable quality and included in the analysis. Baseline characteristics of the two groups were similar (Table 1). The weight and gestational range for the Control group was 635–4400 g, 24.4–42.6 weeks, and for Treatment group, 470–4125 g, 24.4–42.0 weeks. Fifty five percent of the intubated study population required prophylactic surfactant. There were no statistically significant differences in the location of intubation or surfactant administration, nor of patients receiving surfactant.

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Table 1 Baseline characteristics Characteristic

Control

N = 55 Male (%) <1500g (%) Mean corrected gestation (weeks) Median postnatal age at intubation (days) Mean weight (g) Singleton births (%) IUGR (%) RDS at birth (%) Location of intubation: NICU (%) Prophylactic surfactant prior to CXR (%) Location of surfactant administration: NICU (%)

Treatment group

28 60.7 42.9 32.2

27 55.6 37.0 32.5

1

1

P

0.788 1.000 0.870 NS

1956 75.0 14.3 75.0 71.4

1887 77.8 29.6 70.4 62.9

0.813 1.000 0.205 0.768 0.573

60.7

48.1

0.422

76.5

61.5

0.443

The percentage of correct tube placements increased from 48% in the pre-study period to 85 and 93% in the Control and Treatment groups, respectively. Palpation correctly predicted ETT position by CXR in 19 (70%) infants in each group (Table 2). Rates of correctly positioned tubes were higher than 70% due to the fact that malposition was overestimated by palpation, when the ETT was in fact, correctly placed. The trend towards more correctly placed tubes in the Treatment group and adequacy of placement with subgroups were not significant. Prediction of correct ETT position, as well as prediction of initial ETT position (i.e. both correct and suboptimal positions) by palpation and CXR were compared and found to be significantly different. Palpation identified correct tube position in 36 infants, compared to 48 infants by CXR (P = 0.010). Palpation correctly predicted any tube position in 38 infants (70%) compared to 54 infants (100%) by CXR, the gold standard (P = 0.0001). Eight neonates in each group had incorrect predictions of their ETT position by palpation. Of the Control infants, six infants were thought to have low tube placement but had a correct position on CXR, and two infants were noted to have correct placement by palpation, whereas the tube was high in one, low in the other by CXR. Table 2 Prediction of endotracheal tube placement by palpation Position by CXR Prediction by palpation Correct Correct Suboptimal Incorrect

Correct Suboptimal

Total ETTs with correct placement (%)

Control

Treatment

P

17 2

19 0

0.487

1.234

6 2

6 2

1.431

1.234

85

93

0.351

For the Treatment infants, six infants had correct placement of which five were incorrectly thought to be low and one was thought to be high by palpation. Of the two tubes incorrectly determined to be adequate by palpation, both were found to be low by CXR. These differences were not significant between the groups (P = 1.234). Palpation by the trained neonatal fellow was accomplished rapidly and none reported difficulty with the palpation technique in any sized infant. There were no accidental extubations in any infant during the first 24 h of the study. No complication was attributable to the palpation technique and the procedure appeared to be tolerated well in all infants. There was a delay of over 2 h in 26% of the patients (n = 14) in obtaining the CXR. A compound adverse outcome of any complication (atelectasis, air leak, right mainstem intubation, accidental extubation) or death occurring in the first 12 h after intubation was recorded in four Control, compared to two Treatment infants (P = 0.669). One infant in each group had a right main-stem intubation. Two Control infants had air leaks and one Treatment infant had atelectasis, and only one of these three infants, a single Control infant, had a low tube position. There was one death in the Control group from extensive pulmonary interstitial emphysema, which progressed to progressive multi-system failure. This infant had a birth weight of 757 g, an estimated gestational age of 24 weeks and had been intubated for RDS from about 1 min of life. The ETT was assessed as being correctly placed on this infant’s CXR.

4. Discussion The current study resulted in a substantial improvement in the initial correct placement of the endotracheal tube in both the Control and Treatment arms of the study, compared to the pre-study prevalence rate. Possible reasons for the improved ETT placements in our Control infants may have included the inadvertent movement of the ETT during palpation itself, and the re-education of our staff prior to this study regarding the use of the weight based insertion criteria [13]. In addition, the ETT was not re-palpated after securing it at the lip, and thus the tube may have been secured in a different position than was palpated. However, if this were the case, it would be expected that some infants in Control group would have also had their ETT moved inadvertently from an optimal to a suboptimal position. This appears unlikely to have occurred with such a high rate of adequate tube placements. Increased diligence and attention to the correct tube placement by physicians performing the intubation and palpation may have occurred because of the performance of this trial, a so-called Hawthorne effect [14]. This effect has been noted by Schmidt et al. who demonstrated that sick newborns benefit by participation in clinical trials [15]. The increase in correctly placed ETTs’ seen in our study is consistent with the study by Bednarek et al. where 13 out of 13 intubations

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performed using palpation were correctly placed within 1 cm of the interclavicular midpoint, with no complications, compared to only 3 out of 14 intubations using auscultation, instillation of methylene blue via a naso-esophageal tube, or measurement techniques to determine depth of tube insertion [12]. This previous prospective, single center, non-blinded study was preceded by CXR measurements made on 142 non-intubated infants’ tracheas. These clearly showed that the anatomic midpoint of the trachea lay within 0.5 cm of the interclavicular midpoint for 92% of these infants. The CXR, taken in a head neutral position was used to determine ETT position. With other methods, two tubes were positioned at the carina, nine were in the right main stem bronchus with five of these infants additionally experiencing atelectasis or air leaks. Occasional discrepancies were noted between the blinded pediatric radiologist’s interpretation of correct positioning and that of our neonatal staff. Our pediatric radiologist followed the criteria laid down by Kuhns and Poznanski [5] to determine adequacy of placement, based on the anatomic mid-point of the trachea. However, we noted that the caretakers tended to advance the ETT if the ETT tip was observed to be at the thoracic inlet on the CXR. This occurred in one Control patient and two Treatment patients. This appeared related to a belief that the ETT was clinically too high, and thus would risk accidental extubation if left in this position, even though the first thoracic vertebra corresponds to the level of the tracheal mid-point, i.e. the safest position for the ETT tip. Palpation had a placement prediction accuracy that was significantly less than that of the CXR in this study, 70% (n = 38) compared with 100% (n = 54). Thus palpation in the hands of our study personnel was useful where CXR was not immediately available, but is not a substitute for the CXR. The radiologic criteria allowed more latitude for correct position below the interclavicular midpoint as compared to the narrower range for correct position by palpation. Palpation cannot determine the actual position of the carina, and there is only a limited tracheal distance available for such palpation, possibly partially explaining the decreased predictive accuracy of palpation, and the frequent determination that the ET tip was low by palpation when judged to be acceptable by radiologic criteria. Palpation was well tolerated. Less frequent need for ETT manipulation and repeat CXR, as well as a lower incidence of complications was noted when the ETT was moved on the basis of findings by palpation. For three patients in the Treatment group the fellow opted against adjustment of the ETT even though it was felt that the ETT was low, and two of these infants had their ETT moved upwards after the CXR was reviewed. The commonest error was the determination that the ETT was low when it was in correct position as occurred in six Control and five Treatment infants. This may have occurred because the ETT was not moved enough during the palpation to ensure that the tip was actually palpated, and may require more experience by the operator.

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With total tracheal lengths of less than 3.5 cm in the smaller infants, and increasingly smaller and more immature infants being offered support, there is a natural reluctance to pull out the ETT during a palpation attempt for fear of extubating the infant. We believe that better education and training would have resulted in more accurate determination of the actual tube placement and accounts for the observation that correctly placed ETTs were considered to be suboptimal by palpation. In addition, as previously noted, the radiologic criteria allowed a wider range of acceptable tube positions than did palpation, especially for a tube that was judged low by palpation. We found the palpation technique has the benefit of being rapid, simple, non-invasive and teachable. The smallest infants have the least reserves and therefore would be expected to derive the maximum benefit from early detection of suboptimal placement. These same infants have the smallest amount of subcutaneous tissue and cartilage, making palpation relatively easier. We believe that further education regarding this technique would result in a higher percent of correctly placed ETTs prior to the initiation of mechanical ventilation and a lesser chance of right main stem intubation and surfactant administration into one lung, which would be especially beneficial in the DR. 5. Conclusions Suprasternal endotracheal palpation is a simple, safe, and useful method of confirming ETT position when CXR is not immediately available, as occurs during resuscitation. The correct use of this technique can reduce the rates of tube related complications. In view of the simplicity and safety of the technique, the palpation technique warrants further study. From the results of the present study a CXR is still recommended for confirmation of an initial ETT placement.

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