Intensive Care Med (2011) 37:430–434 DOI 10.1007/s00134-010-2114-z
Armand Mekontso Dessap Olivier Proost Florence Boissier Bruno Louis Ferran Roche Campo Laurent Brochard
ORIGINA L
Transesophageal echocardiography in prone position during severe acute respiratory distress syndrome
Abstract Objective: Patients with severe acute respiratory distress syndrome (ARDS) often require prolonged sessions of prone position (PP) because of refractory hypoxemia. Because of frequent Electronic supplementary material The online version of this article hemodynamic impairment, use of (doi:10.1007/s00134-010-2114-z) contains transesophageal echocardiography supplementary material, which is available (TEE) is also advocated during to authorized users. ARDS, but its implementation during PP has not been described yet. Our A. Mekontso Dessap ()) O. Proost F. Boissier F. Roche Campo L. Brochard objective is to report the feasibility, AP-HP, CHU Henri Mondor - Albert tolerance, and therapeutic implicaChenevier, Service de Re´animation tions of TEE during PP for severe Me´dicale, 51 Av Mare´chal de Lattre de ARDS, and to compare it with TEE Tassigny, 94010 Cre´teil, France performed supine. Methods: Proe-mail:
[email protected] spective study in the medical Tel.: ?33-149-812391 intensive care unit of a university Fax: ?33-142-079943 hospital. Results: A total of 34 A. Mekontso Dessap F. Boissier patients with ARDS underwent TEE B. Louis F. Roche Campo L. Brochard in PP. Probe insertion was successful INSERM, U955, Cre´teil 94010, France in all but one patient, and vital signs did not change during insertion. All A. Mekontso Dessap F. Boissier standard views and measures could be F. Roche Campo L. Brochard Universite´ Paris Est Cre´teil Val de Marne, obtained, except for patent foramen Faculte´ de Me´decine, 94010 Cre´teil, France ovale in one patient, and cardiac Received: 4 February 2010 Accepted: 29 September 2010 Published online: 4 January 2011 Ó Copyright jointly held by Springer and ESICM 2010
Introduction Patients with acute respiratory distress syndrome (ARDS) often present with multifactorial hemodynamic compromise. The coexistence of septic shock is common, and ARDS by itself can induce right ventricle failure [1, 2]. Transesophageal echocardiography (TEE) is a technique of choice to characterize sepsis-related hemodynamic alterations [3], or acute cor pulmonale [1]. In our unit, all ARDS patients are routinely explored using TEE, on a
output assessment in four patients. TEE examinations were all conclusive and led to therapeutic change proposal in 23 patients (70%). TEE was performed in both supine and PP in 16 patients within a median delay of 3 days. There was no difference between the two examinations in terms of feasibility, tolerance, therapeutic implication, and image quality. In ten healthy individuals, we also explored the minimal cross-sectional area of the oropharyngeal duct with the acoustic reflection technique; it was found identical in supine and PP. Conclusions: TEE can be performed safely and efficiently in severe ARDS patients in PP. PP is not associated with a significant change in the oropharyngeal tract cross-section in healthy individuals. Keywords Echocardiography Lung injury Prone position
systematic basis at ARDS start and whenever any clinical worsening or lack of improvement occurs during disease course. A recent meta-analysis demonstrates that prone position (PP) reduces mortality in ARDS patients with severe hypoxemia [4]. To achieve the benefits of PP, it must, however, be implemented at least 18 h a day [5]. In our intensive care unit, we routinely employ prolonged sessions of PP in ARDS patients with severe hypoxemia. In these patients, it often becomes necessary to perform TEE
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during these prolonged sessions because of persisting respiratory compromise and/or hemodynamic worsening with no obvious explanation. PP could potentially be associated with technical difficulties for performing TEE. In particular, inserting the TEE probe could be limited because of the lateral rotation of patient’s head. The objectives of this prospective study are to determine the feasibility, tolerance, and therapeutic implications of TEE during PP for severe ARDS. We also compared TEE performed in both PP and supine position in a subgroup of patients explored in the two situations. Lastly, in a group of healthy adult subjects, we assessed the impact of PP with head rotation on the diameter of the oropharyngeal tract.
positions: supine, and PP with head rotation either to the right or to the left (see ESM). The minimal area of the oropharyngeal cavity (from incisors to the glottis) was calculated for all subjects in each position. Statistical analysis Data were analyzed using the SPSS Base 13.0 statistical software package (SPSS Inc., Chicago, IL). Continuous data were expressed as median (first quartile–third quartile) and were compared using the Mann–Whitney test for independent samples and the Friedman test for related samples. Categorical variables, expressed as percentages, were evaluated using the chi-square test or Fisher exact test. Twotailed p values\0.05 were considered significant.
Condensed methods Patients
Results
Patients who met American–European Consensus Conference criteria for ARDS [6] and who underwent TEE while in PP because of severe hypoxemia (PaO2/FiO2 ratio \100 mmHg supine despite optimization of alveolar recruitment by increasing positive end-expiratory pressure [PEEP] to obtain plateau pressure of 28–30 cm H2O [7]) were included prospectively between April 2008 and November 2009. Noninclusion criteria were contraindications to TEE and/or PP (see ESM). The study was approved by our institutional ethics committee.
Characteristics of patients undergoing TEE in PP
TEE TEE was performed using an Envisor or iE33 system (Philips Ultrasound, Bothell, WA) equipped with a multiplane 5-MHz TEE transducer (see photo, ESM), following a standard procedure, as previously described [3] (see ESM). Enteral nutrition was interrupted and the gastric contents emptied (gastric suction) before TEE. In patients who underwent TEE in both supine and PP during the hospital course, we compared the feasibility, tolerance, and therapeutic implications of these two explorations. In addition, the image quality of acquired standard views was also compared between the two positions, using a score modified from Cohen et al. [8], as follows: each image was graded by ascribing a value of 1 (poor quality), 2 (satisfactory) or 3 (excellent quality).
A total of 34 consecutive patients (all orally intubated) were included (Table 1). Vital signs did not change significantly during probe insertion for TEE in PP (Table 2), and there was no modification of the ventilatory settings or hemodynamic support. Feasibility, tolerance, and therapeutic implications of TEE in PP The TEE probe was inserted blindly through the midline, after placement of a bite blocker. Probe insertion was successful in all but one patient with severe kyphoscoliosis, with median insertion time of 30 (10–60) s. Direct laryngoscopy was never used. Dislodgement of orogastric tube, vomiting or significant gastrointestinal bleeding was never observed. During TEE in PP, patient’s head was rotated to the right in 19 (61%) cases. Median duration of TEE in PP was 19 (15–30) min. In the 33 patients with successful probe insertion, all standard views and measures could be obtained, except for cardiac output in four patients. Patent foramen ovale was not checked in one patient (already checked the day before while supine). The main findings of TEE in PP are summarized in Table 3. When performed, the examination was always conclusive and led to a proposal of therapeutic change in 23 (70%) patients (see ESM).
Noninvasive assessment of oropharyngeal tract Comparison of TEE in supine and PP We used the two-microphone acoustic reflection method [9] to assess the duct cross-section of the oropharyngeal Sixteen patients underwent TEE in both supine and PP, tract in ten healthy adult volunteers in three consecutive with median delay of 3 days [1–5] between the two
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Table 1 Patient characteristics at baseline and at time of transesophageal echocardiography in prone position (n = 34) Patient characteristic Male/female, n Age (years) Etiologies of lung injury, n (%) Pneumonia Aspiration Other causes SAPS II at ICU admission SOFA at day of TEE Ventilation at time of TEE in PP Assist control mode, n (%) Tidal volume, mL PEEP (cmH2O) Plateau pressure (cmH2O) Blood gas analysis at time of TEE in PP PaO2/FiO2 ratio (mmHg) PaCO2 (mmHg) pH Hemodynamic status at time of TEE in PP Shock, n (%) Norepinephrine, n (%) Epinephrine, n (%) Dobutamine, n (%) Other treatments at time of TEE in PP Muscle paralysis, n (%) Inhaled nitric oxide, n (%) Orogastric tube in place for enteral feeding, n (%) Total duration of mechanical ventilation (days) ICU stay (days) ICU mortality, n (%)
27/7 62 (45–71) 20 (59) 6 (18) 8 (23) 57 (40–72) 9 (7–12)
in PP or supine position in terms of feasibility, tolerance or therapeutic implications (Table 4). In seven patients with both supine and prone TEE studies, image quality of standard views acquired was comparable, with scores of 2.2 (1.8–2.5) and 1.8 (1.6–2.7), respectively. Noninvasive assessment of oropharyngeal tract patency
34 (100) 400 (355–446) 10 (7–14) 26 (22–29) 124 (62–164) 44 (36–57) 7.36 (7.27–7.40) 25 (74) 22 (65) 3 (9) 3 (9)
There was no significant difference in the minimal crosssectional area of the oropharyngeal tract (from incisors to the glottis) in ten healthy individuals assessed in three consecutive positions: 1.8 (1.6–2.4) cm2 while supine versus 2.0 (1.6–2.6) cm2 in PP with head rotation to the right and 2.1 (1.8–2.9) cm2 in PP with head rotation to the left (p = 0.27) (Fig. 1).
Discussion
This is the first study to demonstrate that TEE can be performed in severe ARDS patients in PP. The tolerance, image quality, and therapeutic implications of TEE were similar in supine and PP. Additionally, the acoustic 16 (7–31) reflection study found no narrowing of the oropharyngeal tract during PP in healthy individuals. 19 (8–34) PP is associated with head rotation, which theoreti18 (53) cally could compromise TEE probe insertion. Instead, we TEE transesophageal echocardiography, PP prone position, SAPS observed a similar probe insertion success rate in supine II simplified acute physiologic score II, SOFA sepsis-related organ and PP. The male predominance in our population (79%) failure assessment, ICU intensive care unit, PEEP positive endmay partly explain this high success rate, because sizes of expiratory pressure the pharynx and oropharyngeal junction are greater in men than women [10]. We found no narrowing of the examinations. More patients were receiving muscle oropharynx of healthy volunteers in PP, as compared with paralysis during TEE in PP as compared with supine supine position. In half of individuals evaluated, the position (Table 4). There was no difference between TEE minimal cross-sectional area was even higher in PP as 31 (91) 9 (27) 30 (88)
Table 2 Vital signs during transesophageal echocardiography in prone position (n = 33) Parameter
Before probe insertion
After probe insertion
p-Value
Systolic arterial pressure (mmHg) Heart rate (bpm) Respiratory frequency (bpm) Transcutaneous oxygen saturation (%)
110 97 30 98
110 99 30 97
0.68 0.89 0.49 0.24
(100–131) (80–119) (26–30) (94–100)
(99–126) (80–116) (28–30) (94–100)
Table 3 Main findings of transesophageal echocardiography in prone position (n = 33) Parameter
Findings
Superior vena cava collapse Left ventricle systolic function Cor pulmonale Filling pressures Shunting across patent foramen ovale
Absent (n = 28) Preserved (n = 22) Absent (n = 22) Low (n = 27) Absent (n = 25)
Present (n = 5) Decreased (n = 11) Present (n = 11) Normal or high (n = 6) Present (n = 7)
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Table 4 Comparison of transesophageal echocardiography in prone and supine positions (n = 16)
Orogastric tube in place during TEE examination, n (%) Muscle paralysis, n (%) Successful probe insertion, n (%) Successful assessment of, n (%) Four-chamber long-axis view Transgastric short-axis view Cardiac output measurement Transmitral flow SVC respiratory variations Patency of foramen ovalea Echocardiography duration, min Conclusive examination, n (%) Proposal of a therapeutic change, n (%)
Prone position (n = 16)
Supine position (n = 16)
p
14 (88) 16 (100) 16 (100)
10 (63) 7 (44) 16 (100)
0.22 \0.01 0.99
16 16 13 16 16 15 20 16 10
16 16 14 15 15 15 24 16 12
(100) (100) (81) (100) (100) (94) (16–25) (100) (63)
(100) (100) (88) (94) (94) (94) (17–31) (100) (75)
0.99 0.99 0.55 0.99 0.99 0.99 0.43 0.99 0.70
TEE transesophageal echocardiography, SVC superior vena cava a Shunting across patent foramen ovale was not checked in one patient because the diagnosis had been already excluded by a previous examination
Minimal cross sectional area, cm2
4
3
2
1
0 Supine
Prone with head rotation to the right
Prone with head rotation to the left
Position
Fig. 1 Minimal cross-sectional area of ten healthy individuals in supine position, prone position with head rotation to the right, and prone position with head rotation to the left
satisfactory and similar in PP and supine position. Although the superior and lateral aspects of the heart were shown to move anteriorly during PP [15], manipulations of the TEE probe to obtain various views are identical regardless of patient position. However, the necessity of placing the echo device on the side of patient’s head rotation during TEE in PP should be emphasized and may require a longer preparation time (that was not assessed in our study) to avoid operator discomfort during examination. The high success rate in standard views assessment in our study may be explained by the image quality of echo devices used, operator experience, but also patient conditions. Indeed, almost all patients explored in PP were paralyzed, and this may have facilitated probe insertion and image acquisition. Both supine and PP patients had orogastric tubes and this did not seem to make a major difference to image quality in either case. We studied a particularly severe group of ARDS patients. The good tolerance of TEE in PP may be reassuring in this context, but our data cannot be extrapolated to other patient groups. Our work has other limitations. First, the number of patients included is relatively small. Exploring more patients may allow intolerance phenomena with rare occurrence to be highlighted. In particular, the increased risk of vomiting and aspiration should be kept in mind when performing TEE in PP. Second, the time elapsed between TEE in supine and PP (median 3 days) may weaken the strength of our comparison because of possible changes in patient condition. In conclusion, TEE can be safely and efficiently performed in severe ARDS patients in PP. This finding may encourage physicians who use TEE to explore ARDS patients to continue hemodynamic assessments even when patients are in PP for prolonged sessions.
compared with supine position. These data are in agreement with previous studies reporting a widening of the upper esophagus sphincter during head rotation [11]. However, data from healthy volunteers are not directly transposable to ARDS patients because of several differences (tracheal cuff, orogastric tube, sedation, and muscle paralysis). A pediatric TEE probe was previously used to assess dorsal lung density area in PP [12]. We herein demonstrate good tolerance of TEE (using an adult probe) for cardiovascular assessment in PP, as previously reported in supine Acknowledgments Support was provided solely from institutional position [13, 14]. The quality of TEE images was and departmental sources.
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