G Model
ACCPM-7; No. of Pages 4 Anaesth Crit Care Pain Med xxx (2015) xxx–xxx
Original article
Implementation of lung ultrasound in polyvalent intensive care unit: Impact on irradiation and medical cost L. Zieleskiewicz a,*, A. Cornesse a, E. Hammad a, M. Haddam a, C. Brun a, C. Vigne a, B. Meyssignac a, A. Remacle b, K. Chaumoitre c, F. Antonini a, C. Martin a, M. Leone a a b c
Department of anesthesiology and critical care medicine, Nord hospital, AP–HM, Aix Marseille university, Marseille, France Department of medical informatics, Nord hospital, AP–HM, Aix Marseille university, Marseille, France Department of radiology, Nord hospital, AP–HM, Aix Marseille university, Marseille, France
A R T I C L E I N F O
A B S T R A C T
Article history: Available online xxx
Objective: To determine the effect of implementing a daily lung ultrasound round on the number of chest radiographs and chest computed tomography (CT) scans in a polyvalent intensive care unit (ICU). Study design: Retrospective study comparing two consecutive periods. Patients: All patients hospitalized for longer than 48 hours in a polyvalent ICU. Methods: Implementation of a daily lung ultrasound round after a short educational program. The number of chest radiographs and chest CT scans and the patient outcome were measured before (group PRE) and after (group POST) the implementation of a daily lung ultrasound round. Results: No demographic difference was found between the two groups, with the exception of a higher severity score in the group POST. For each ICU stay, the number of chest radiographs was 10.3 12.4 in the group PRE and 7.7 10.3 in the group POST, respectively (P < 0.005) The number of chest CT scans was not reduced in the group POST, as compared with the group PRE (0.5 0.7 CT scan/patient/ICU stay versus 0.4 0.6 CT scan/patient/ICU stay, P = 0.01). The ICU mortality was similar in both groups (21% versus 22%, P = 0.75) Conclusion: The implementation of a daily lung ultrasound round was associated with a reduction in radiation exposure and medical cost without altering patient outcome. ß 2015 Socie´te´ franc¸aise d’anesthe´sie et de re´animation (Sfar). Published by Elsevier Masson SAS. All rights reserved.
Keywords: Radiograph Computed tomography scan Ultrasound Lung Critical care
Diagnosis imaging is a frequent procedure in intensive care unit (ICU). The large prescription of chest radiographs is associated with increased radiation exposure [1–3]. The recourse to computed tomography (CT) scans exposes to potential harmful mobilization [4]. Restrictive use of chest radiographs was associated with better diagnostic and therapeutic efficacies without affecting outcome [5–7]. Lung ultrasound provides more information than chest radiographs [8–13]. Its performance is close to that of chest CT scan, without radiation exposure [8,10,14]. In ICU, the introduction
* Corresponding author. E-mail addresses: [email protected] (L. Zieleskiewicz), [email protected] (A. Cornesse), [email protected] (E. Hammad), [email protected] (M. Haddam), [email protected] (C. Brun), [email protected] (C. Vigne), [email protected] (B. Meyssignac), [email protected] (A. Remacle), [email protected] (K. Chaumoitre), [email protected] (F. Antonini), [email protected] (C. Martin), [email protected] (M. Leone).
of lung ultrasound has been associated with a reduced use of chest radiographs [15]. Clinicians are sometimes reluctant to abandon daily routine chest radiograph. The loss of information is a concern explaining the broad use of chest radiograph. We hypothesized that the routine use of a daily lung ultrasound round may have resulted in a decrease of chest radiograph prescription, without affecting the patient outcome. The first goal of our study was to determine the effect of a daily bedside ultrasound round on the number of chest radiographs. The secondary goal was to assess the effect of this procedure on the number of CT scan and medical cost. 1. Materials and methods We conducted a retrospective study in a 15-bed-ICU of a tertiary hospital (928 beds). According to the French legislation (articles L. 1121-1 paragraph 1 and R. 1121-2, Public Health Code), informed consent and approval by the Ethics Committee were waived due to the retrospective nature of the study. All the patients
http://dx.doi.org/10.1016/j.accpm.2015.01.002 2352-5568/ß 2015 Socie´te´ franc¸aise d’anesthe´sie et de re´animation (Sfar). Published by Elsevier Masson SAS. All rights reserved.
Please cite this article in press as: Zieleskiewicz L, et al. Implementation of lung ultrasound in polyvalent intensive care unit: Impact on irradiation and medical cost. Anaesth Crit Care Pain Med (2015), http://dx.doi.org/10.1016/j.accpm.2015.01.002
G Model
ACCPM-7; No. of Pages 4 L. Zieleskiewicz et al. / Anaesth Crit Care Pain Med xxx (2015) xxx–xxx
2
with an ICU stay > 48 hours hospitalized from May 1, 2011 to May 1, 2012 were included in the study. A before/after model was applied to a cohort of patients hospitalized in ICU for longer than 48 hours, as following: in group PRE, we included the patients admitted to the ICU from May 1, 2011 to October 31, 2011. During this period, lung ultrasound was an uncommon practice in our ICU. The team member did not receive a specific training about this procedure. With respect to chest radiographs, the system was based on an on-demand practice without strict written protocol to monitor the prescriptions. Chest CT scans were performed on the decision of the senior physician (Fig. 1); in group POST, we included the patients admitted to the ICU from November 1, 2011 to May 1, 2012. During this period, the residents were briefly trained by ultrasound certified physicians. This training consisted on a 2-hours theoretical lecture [16–20]. At the bedside, about 20 lung ultrasound exams were then performed under the supervision of a senior. The signs related to normal lung, interstitial syndrome, lung consolidation, pneumothorax and pleural effusion were identified. After this training, on a daily basis, a resident was affected to a ‘‘lung ultrasound round’’. During this round, she or he performed an on-demand lung ultrasound exam as requested by her or his senior physician.
The ultrasound findings were reported to the senior physicians during the daily round. With respect to chest radiographs and CT scans, no protocol was implemented in the ICU about diagnosis imaging (Fig. 1). The lung was examined in semi-seated position with an abdominal probe (C5-1, Philips CX 50 CompactXtreme [Philips Medical systemsTM, Suresnes, France]). Twelve lung regions were assessed in each patient, and the Lung Ultrasound Score was calculated [19]. Pleural effusion, interstitial syndrome, pneumothorax and consolidation were identified during the ultrasound examination. All the findings were collected in a dedicated electronic database. Chest radiographs and CT scans were still prescribed on-demand. Radiographs that were performed from 8:00 (am) to 10:00 (am) and on admission were considered as routine chest X-rays. Other radiographs were considered as unscheduled chest X-rays. Physicians were unaware of the study. Thus, the study measured the effect of ultrasound implementation on chest radiograph prescription without implementing effective guidelines. We extracted from our database the following variables: age, sex, simplified acute physiology score (SAPS) II, reason for admission, mechanical ventilation duration, duration of ICU stay, 807 hospitalized paents in ICU 309 hospitalized less than 48 hours 498 eligible 242 Group PRE From May 1, 2011 to October 31, 2011 50 admied for thoracic surgery 192 Group PRE Aer exclusion of paents admied for thoracic surgery From May 1, 2011 to October 31, 2011
256 Group POST From November 1, 2011 to May 1, 2012 54 admied for thoracic surgery 202 Group POST Aer exclusion of paents admied for thoracic surgery From November 1, 2011 to May 1, 2012
Fig. 1. Study flowchart. ICU: intensive care unit.
duration of hospital stay, ICU mortality, and hospital mortality. The number of chest radiographs, the features of chest radiographs (emergent or elective), and the number of chest CT scans were collected. Statistical analysis was performed using R software version 2.13. Univariate analysis of before/after data was performed using Mann–Whitney and Chi2 tests. Data are expressed as medians and interquartiles or means and standard deviations. A value of P below 0.05 defined the significance. As chest radiographs or chest CT scans were often directly demanded by thoracic surgeons for personal use, a subgroup analysis was conducted after excluding the patients undergoing ICU after thoracic surgery. 2. Results As show in the flow chart of the study, 498 patients met the criteria for inclusion (Fig. 1). Medicine, surgery, and trauma were the causes of admission in 46%, 19%, and 35% of the cases, respectively The demographic features were similar in the two groups, with the exception of SAPS II (Table 1). The durations of mechanical ventilation, ICU stay, and hospital stay did not differ in the two groups. The ICU mortality rate was 21% in the group PRE, as compared with 22% in the group POST (P = 0.75) (Table 1). For each ICU stay, the absolute number of chest radiographs was 10.3 12.4 in the group PRE and 7.7 10.3 in the group POST, respectively (P < 0.0005) (Table 2). The effect was maximal in the last quarter (Fig. 2). Of note, the absolute number of unscheduled chest radiographs was similar in both groups (3.7 3.9 vs. 3.4 3.5, P = 0.27). With respect to chest CT scan, the number of procedures change 0.5 0.7 CT scan/ICU stay in the group PRE to 0.4 0.6 CT scan/ICU stay in the group POST (P = 0.01) (Table 2). After exclusion of 104 patients admitted to the ICU after thoracic surgery, the absolute number of chest radiographs (for Table 1 Characteristics of patients and outcome. Variables
PRE (n = 242)
POST (n = 256)
P
Age (years) Male (%) SAPS II Admission diagnosis, (%) Trauma patient Surgical patient Medical patient Duration of ICU stay (day) Duration of hospital stay (day) Duration of mechanical ventilation (day) ICU mortality (%) Hospital mortality (%)
54 [38–66] 182 (75) 32 [22–44]
56 [41–69] 177 (69) 36 [26–49]
0.11 0.15 0.005
96 (40) 51 (21) 95 (39) 5 [3–11] 20 [10–33] 1 [0–6]
79 (31) 41 (16) 136 (53%) 5 [3–10] 18 [10–31] 2 [0–7]
0.01 0.01 0.01 0.5 0.72 0.09
51 (21) 62 (25)
58 (22) 71 (27)
0.75 0.66
Results are expressed as median and interquartiles or absolute number and percentage. SAPS: simplified acute physiology score; ICU: Intensive care unit; PRE: before daily lung ultrasound implementation; POST: after daily lung ultrasound implementation.
Table 2 Number of chest radiographs and computed tomography (CT) scan during the intensive care unit (ICU) stay according to the study period (PRE: before daily lung ultrasound implementation; POST: after daily lung ultrasound implementation).
Number of chest radiograph/ICU stay Number of unscheduled chest radiograph/ICU stay Number of chest CT scan/ICU stay
PRE (n = 242)
POST (n = 256)
P
10.3 12.4 3.7 3.9
7.7 10.3 3.4 3.5
< 0.0005 0.27
0.5 0.7
0.4 0.6
0.01
Results are expressed as mean and standard derivation.
Please cite this article in press as: Zieleskiewicz L, et al. Implementation of lung ultrasound in polyvalent intensive care unit: Impact on irradiation and medical cost. Anaesth Crit Care Pain Med (2015), http://dx.doi.org/10.1016/j.accpm.2015.01.002
G Model
ACCPM-7; No. of Pages 4 L. Zieleskiewicz et al. / Anaesth Crit Care Pain Med xxx (2015) xxx–xxx
Fig. 2. Mean number of chest radiograph per patient per ICU stay, according to 3 months periods. Period 1 from May 1 to July 31, 2011. Period 2 from August 1 to October 31, 2011. Period 3 from November 1, 2011 to January 31, 2012. Period 4 from February 1 to May 1, 2012.
Table 3 Number of chest radiographs and computed tomography (CT) scan during the intensive care unit (ICU) stay according to the study period (PRE: before daily lung ultrasound implementation; POST: after daily lung ultrasound implementation) after exclusion of 104 patients admitted for thoracic surgery (postoperative care or complication).
Number of chest radiograph/ICU stay Number of chest CT scan/ICU stay
PRE (n = 192)
POST (n = 202)
P
9.4 11.0 0.6 1.0
6.4 8.0 0.4 1.0
0.0001 0.007
Results are expressed as mean and standard derivation.
each ICU stay) was 9.4 11.0 in the group PRE and 6.4 8.0 in the group POST, respectively (P = 0.0001). The number of CT scans was 0.6 1.0 in the group PRE versus 0.4 1.0 in the group POST (P = 0.007) (Table 3). 3. Discussion Our results show that the implementation of a ‘‘daily lung ultrasound round’’ was associated with a reduced use of routine chest radiographs and chest CT scans. One may extrapolate that this result was associated with reduced cost and decreased radiation exposure. In addition, one can expect that the reduced number of patient mobilizations may prevent harmful events. During the study, the ICU staff members were blinded about the study design. No specific protocol was implemented in order to reduce the radiation exposure. This means that our study strictly measured the effect of the daily lung ultrasound round, independently of protocols aimed at reducing radiation exposure. Our results, in line with a previous study [15], show that lung ultrasound facilitated the control of prescription of chest radiographs. However, in this previous study, ultrasound was only used for the detection of pleural effusion. In the present study, ultrasound served to identify both pleural and parenchyma pathologic entities. The number of chest radiographs decreased by 24% during the study period. This represents yearly around 1000 chest radiographs. In our ICU, the large use of chest radiograph is partly explained by a large number of trauma patients. The recourse to chest CT scan was reduced by 15%, representing 50 chest CT scans yearly. In terms of radiation, this corresponds to a 1050 mGy reduction, i.e. 1000 maximal annual doses. In our structure the respective costs of a chest radiograph and a chest CT scan are around 25 s and 130 s. Thus, we evaluated that the cost was
3
decreased by around 30,000 s/year i.e. about the cost of a small ultrasound machine. We noted a maximal effect during the late phase (last quarter) of our approach. The absolute prescription of chest radiographs did not significantly change after the first quarter of lung ultrasound implementation (period 3). This probably reflects the learning curve, and the time required for the appropriation of this technology [17]. For this period, chest radiographs were probably required in order to confirm the findings of ultrasound examination. This hypothesis was also suggested in a previous study [15]. The number of unscheduled chest radiographs did not change over the study period. Unscheduled chest radiographs may have been prescribed for device control or urgent clinical conditions. For device control, lung ultrasound can be an alternative to chest radiograph [21–23]. Nevertheless, in our study, lung ultrasound was not used in this indication. This probably explains the lack of decrease of their use. Similar finding was reported in a previous study [15]. With respect to the use of chest radiographs in urgent situation, this result can be related to a lack of confidence of physicians with ultrasound in patients with life-threatening conditions. Future prospective studies are required to confirm these results. Our findings are reinforced after the exclusion of patients admitted after thoracic surgery for postoperative care or complications. The surgical features may explain the need for chest radiograph. However, the chest radiograph probably facilitates the interface between members of different teams. In order to reduce the radiation exposure, there is a need to share basic knowledge on ultrasound between surgeons and intensivists. To this purpose, a short training of thoracic surgeons was implemented in our hospital. Future studies are required to evaluate the impact of this process. Our study has several limitations that we have to acknowledge. The retrospective design can induce a loss of information. However, we used data extracted from our electronic database, and the loss of information was minimal. In our unit, the prescription of chest radiographs is liberal. No formal written protocol has been implemented for reducing radiation exposure. This lack of protocol made it possible to measure the effect of the daily lung ultrasound round without altering the background noise during the study period. The study was performed in a single center, and a local effect may have impacted our findings. Due to the low number of CT scan/patient, we observed a large variability that can be regarded as a limitation. The increase number of trauma patients during the PRE period may have affected the results. However, there is no clear evidence showing that chest Xrays are more often used in trauma patients than in medical patients. Of more, patients in the POST period had a higher severity score. Finally, the performance of a lung ultrasound is timeconsumer, limiting the diffusion of this strategy in ICU with a large number of physicians. In conclusion, our study confirms that the introduction of a daily lung ultrasound round is associated with a decreased use of routine chest radiographs and chest CT scans. This strategy probably reduces the cost and radiation exposure. Of note, this result was obtained without altering patient outcome. The introduction of protocols formalizing the respective indications for each examination may increase this effect and remains to be tested in a multicenter and randomized clinical trial. Disclosure of interest The authors declare that they have no conflicts of interest concerning this article. Acknowledgments Authors thank Dr. F. Craighero and Dr. C. Arbelot for their help.
Please cite this article in press as: Zieleskiewicz L, et al. Implementation of lung ultrasound in polyvalent intensive care unit: Impact on irradiation and medical cost. Anaesth Crit Care Pain Med (2015), http://dx.doi.org/10.1016/j.accpm.2015.01.002
G Model
ACCPM-7; No. of Pages 4 L. Zieleskiewicz et al. / Anaesth Crit Care Pain Med xxx (2015) xxx–xxx
4
References [1] Fazel R, Krumholz HM, Wang Y, Ross JS, Chen J, Ting HH, et al. Exposure to lowdose ionizing radiation from medical imaging procedures. N Engl J Med 2009;27:849–57. [2] Brenner DJ, Hall EJ. Computed tomography: an increasing source of radiation exposure. N Engl J Med 2007;29:2277–84. [3] Rohner DJ, Bennett S, Samaratunga C, Jewell ES, Smith JP, Gaskill-Shipley M, et al. Cumulative total effective whole-body radiation dose in critically ill patients. Chest 2013;144:1481–6. [4] Voigt LP, Pastores SM, Raoof ND, Thaler HT, Halpern NA. Review of a large clinical series: intrahospital transport of critically ill patients: outcomes, timing, and patterns. J Intensive Care Med 2009;24:108–15. [5] Clec’h C, Simon P, Hamdi A, Hamza L, Karoubi P, Fosse JP, et al. Are daily routine chest radiographs useful in critically ill, mechanically ventilated patients? A randomized study. Intensive Care Med 2008;34:264–70. [6] Hendrikse KA, Gratama JW, Hove WT, Rommes JH, Schultz MJ, Sponk PE. Low value of routine chest radiographs in a mixed medical-surgical ICU. Chest 2007;132:823–8. [7] Graat ME, Choi G, Wolthuis EK, Korevaar JC, Sponk PE, Stoker J, et al. The clinical value of daily routine chest radiographs in a mixed medical-surgical intensive care unit is low. Crit Care 2006;10:R11. [8] Lichtenstein D, Goldstein I, Mourgeon E, Cluzel P, Grenier P, Rouby JJ. Comparative diagnostic performances of auscultation, chest radiography, and lung ultrasonography in acute respiratory distress syndrome. Anesthesiology 2004;100:9–15. [9] Bouhemad B, Zhang M, Lu Q, Rouby JJ. Clinical review: bedside lung ultrasound in critical care practice. Crit Care 2007;11:205. [10] Xirouchaki N, Magkanas E, Vaporidi K, Kondili E, Plataki M, Patrianakos A, et al. Lung ultrasound in critically ill patients: comparison with bedside chest radiography. Intensive Care Med 2011;37:1488–93. [11] Lichtenstein DA, Mezie`re G, Lascols N, Biderman P, Courret JP, Gepner A, et al. Ultrasound diagnosis of occult pneumothorax. Crit Care Med 2005;33: 1231–8. [12] Zanforlin A, Giannuzzi R, Nardini S, Testa A, Soldati G, Copetti R, et al. The role of chest ultrasonography in the management of respiratory diseases. Multidiscip Respir Med 2013;8:54. [13] Alrajhi K, Woo MY, Vaillancourt C. Test characteristics of ultrasonography for the detection of pneumothorax. Chest 2012;141:703–8. [14] Shankar H, Pagel PS. Potential adverse ultrasound-related biological effects: a critical review. Anesthesiology 2011;115:1109–24. [15] Peris A, Tutino L, Zagli G, Batacchi S, Cianchi G, Spina R, et al. The use of point-of-care bedside lung ultrasound significantly reduces the number
[16]
[17]
[18]
[19]
[20]
[21]
[22]
[23]
of radiographs and computed tomography scans in critically ill patients. Anesth Analg 2010;111:687–92. Volpicelli G, Elbarbary M, Blaivas M, Lichtenstein DA, Mathis G, Kirkpatrick AW, et al. International liaison committee on lung ultrasound (ILC-LUS) for international consensus conference on lung ultrasound (ICC-LUS). International evidence-based recommendations for point-of-care lung ultrasound. Intensive Care Med 2012;38:577–91. Tutino L, Cianchi G, Barbani F, Batacchi S, Cammelli R, Peris A. Time needed to achieve completeness and accuracy in bedside lung ultrasound reporting in intensive care unit. Scand J Trauma Resusc Emerg Med 2010;12:18–44. Zieleskiewicz L, Arbelot C, Hammad E, Brun C, Textoris J, Martin C, et al. Lung ultrasound: clinical applications and perspectives in intensive care unit. Ann Fr Anesth Reanim 2012;31:793–801. Bouhemad B, Brisson H, Le-Guen M, Arbelot C, Lu Q, Rouby JJ. Bedside ultrasound assessment of positive end-expiratory pressure induced lung recruitment. Am J Respir Crit Care Med 2011;183:341–7. Chalumeau-Lemoine L, Baudel JL, Das V, Arrive´ L, Noblinski B, Guidet B, et al. Results of short-term training of naı¨ve physicians in focused general ultrasonography in a intensive care unit. Intensive Care Med 2009;35:1767–71. Galbois A, Ait-Oufella H, Baudel JL, Kofman T, Bottero J, Viennot S, et al. Pleural ultrasound compared with chest radiographic detection of pneumothorax resolution after drainage. Chest 2010;138:648–55. Maury E, Guglielminotti J, Alzieu M, Guidet B, Offenstadt G. Ultrasonic examination: an alternative to chest radiography after central venous catheter insertion? Am J Respir Crit Care Med 2001;164:403–5. Vigneau C, Baudel JL, Guidet B, Offenstadt G, Maury E. Sonography as an alternative to radiography for nasogastric feeding tube location. Intensive Care Med 2005;31:1570–2.
Further reading Koegelenberg C, Von Groote-Bidlingmaier F, Bolliger CT. Transthoracic ultrasonography for the respiratory physician. Respiration 2012;84:337–50. Ioos V, Galbois A, Chalumeau-Lemoine L, Guidet B, Maury E, Hejblum G. An integrated approach for prescribing fewer chest X-rays in the ICU. Ann Intensive Care 2011;1:4. Nazerian P, Vanni S, Volpicelli G, Gigli C, Zanobetti M, Bartolucci M, et al. Accuracy of point-of-care multiorgan ultrasonography for the diagnosis of pulmonary embolism. Chest 2013;10:1087. Koenig S, Chandra S, Alaverdian A, Dibello C, Mayo PH, Narasimhan M. Ultrasound assessment of pulmonary embolism in patients receiving computerized tomography pulmonary angiography. Chest 2013;10:797.
Please cite this article in press as: Zieleskiewicz L, et al. Implementation of lung ultrasound in polyvalent intensive care unit: Impact on irradiation and medical cost. Anaesth Crit Care Pain Med (2015), http://dx.doi.org/10.1016/j.accpm.2015.01.002
ACCPM-7; No. of Pages 4 Anaesth Crit Care Pain Med xxx (2015) xxx–xxx
Original article
Implementation of lung ultrasound in polyvalent intensive care unit: Impact on irradiation and medical cost L. Zieleskiewicz a,*, A. Cornesse a, E. Hammad a, M. Haddam a, C. Brun a, C. Vigne a, B. Meyssignac a, A. Remacle b, K. Chaumoitre c, F. Antonini a, C. Martin a, M. Leone a a b c
Department of anesthesiology and critical care medicine, Nord hospital, AP–HM, Aix Marseille university, Marseille, France Department of medical informatics, Nord hospital, AP–HM, Aix Marseille university, Marseille, France Department of radiology, Nord hospital, AP–HM, Aix Marseille university, Marseille, France
A R T I C L E I N F O
A B S T R A C T
Article history: Available online xxx
Objective: To determine the effect of implementing a daily lung ultrasound round on the number of chest radiographs and chest computed tomography (CT) scans in a polyvalent intensive care unit (ICU). Study design: Retrospective study comparing two consecutive periods. Patients: All patients hospitalized for longer than 48 hours in a polyvalent ICU. Methods: Implementation of a daily lung ultrasound round after a short educational program. The number of chest radiographs and chest CT scans and the patient outcome were measured before (group PRE) and after (group POST) the implementation of a daily lung ultrasound round. Results: No demographic difference was found between the two groups, with the exception of a higher severity score in the group POST. For each ICU stay, the number of chest radiographs was 10.3 12.4 in the group PRE and 7.7 10.3 in the group POST, respectively (P < 0.005) The number of chest CT scans was not reduced in the group POST, as compared with the group PRE (0.5 0.7 CT scan/patient/ICU stay versus 0.4 0.6 CT scan/patient/ICU stay, P = 0.01). The ICU mortality was similar in both groups (21% versus 22%, P = 0.75) Conclusion: The implementation of a daily lung ultrasound round was associated with a reduction in radiation exposure and medical cost without altering patient outcome. ß 2015 Socie´te´ franc¸aise d’anesthe´sie et de re´animation (Sfar). Published by Elsevier Masson SAS. All rights reserved.
Keywords: Radiograph Computed tomography scan Ultrasound Lung Critical care
Diagnosis imaging is a frequent procedure in intensive care unit (ICU). The large prescription of chest radiographs is associated with increased radiation exposure [1–3]. The recourse to computed tomography (CT) scans exposes to potential harmful mobilization [4]. Restrictive use of chest radiographs was associated with better diagnostic and therapeutic efficacies without affecting outcome [5–7]. Lung ultrasound provides more information than chest radiographs [8–13]. Its performance is close to that of chest CT scan, without radiation exposure [8,10,14]. In ICU, the introduction
* Corresponding author. E-mail addresses: [email protected] (L. Zieleskiewicz), [email protected] (A. Cornesse), [email protected] (E. Hammad), [email protected] (M. Haddam), [email protected] (C. Brun), [email protected] (C. Vigne), [email protected] (B. Meyssignac), [email protected] (A. Remacle), [email protected] (K. Chaumoitre), [email protected] (F. Antonini), [email protected] (C. Martin), [email protected] (M. Leone).
of lung ultrasound has been associated with a reduced use of chest radiographs [15]. Clinicians are sometimes reluctant to abandon daily routine chest radiograph. The loss of information is a concern explaining the broad use of chest radiograph. We hypothesized that the routine use of a daily lung ultrasound round may have resulted in a decrease of chest radiograph prescription, without affecting the patient outcome. The first goal of our study was to determine the effect of a daily bedside ultrasound round on the number of chest radiographs. The secondary goal was to assess the effect of this procedure on the number of CT scan and medical cost. 1. Materials and methods We conducted a retrospective study in a 15-bed-ICU of a tertiary hospital (928 beds). According to the French legislation (articles L. 1121-1 paragraph 1 and R. 1121-2, Public Health Code), informed consent and approval by the Ethics Committee were waived due to the retrospective nature of the study. All the patients
http://dx.doi.org/10.1016/j.accpm.2015.01.002 2352-5568/ß 2015 Socie´te´ franc¸aise d’anesthe´sie et de re´animation (Sfar). Published by Elsevier Masson SAS. All rights reserved.
Please cite this article in press as: Zieleskiewicz L, et al. Implementation of lung ultrasound in polyvalent intensive care unit: Impact on irradiation and medical cost. Anaesth Crit Care Pain Med (2015), http://dx.doi.org/10.1016/j.accpm.2015.01.002
G Model
ACCPM-7; No. of Pages 4 L. Zieleskiewicz et al. / Anaesth Crit Care Pain Med xxx (2015) xxx–xxx
2
with an ICU stay > 48 hours hospitalized from May 1, 2011 to May 1, 2012 were included in the study. A before/after model was applied to a cohort of patients hospitalized in ICU for longer than 48 hours, as following: in group PRE, we included the patients admitted to the ICU from May 1, 2011 to October 31, 2011. During this period, lung ultrasound was an uncommon practice in our ICU. The team member did not receive a specific training about this procedure. With respect to chest radiographs, the system was based on an on-demand practice without strict written protocol to monitor the prescriptions. Chest CT scans were performed on the decision of the senior physician (Fig. 1); in group POST, we included the patients admitted to the ICU from November 1, 2011 to May 1, 2012. During this period, the residents were briefly trained by ultrasound certified physicians. This training consisted on a 2-hours theoretical lecture [16–20]. At the bedside, about 20 lung ultrasound exams were then performed under the supervision of a senior. The signs related to normal lung, interstitial syndrome, lung consolidation, pneumothorax and pleural effusion were identified. After this training, on a daily basis, a resident was affected to a ‘‘lung ultrasound round’’. During this round, she or he performed an on-demand lung ultrasound exam as requested by her or his senior physician.
The ultrasound findings were reported to the senior physicians during the daily round. With respect to chest radiographs and CT scans, no protocol was implemented in the ICU about diagnosis imaging (Fig. 1). The lung was examined in semi-seated position with an abdominal probe (C5-1, Philips CX 50 CompactXtreme [Philips Medical systemsTM, Suresnes, France]). Twelve lung regions were assessed in each patient, and the Lung Ultrasound Score was calculated [19]. Pleural effusion, interstitial syndrome, pneumothorax and consolidation were identified during the ultrasound examination. All the findings were collected in a dedicated electronic database. Chest radiographs and CT scans were still prescribed on-demand. Radiographs that were performed from 8:00 (am) to 10:00 (am) and on admission were considered as routine chest X-rays. Other radiographs were considered as unscheduled chest X-rays. Physicians were unaware of the study. Thus, the study measured the effect of ultrasound implementation on chest radiograph prescription without implementing effective guidelines. We extracted from our database the following variables: age, sex, simplified acute physiology score (SAPS) II, reason for admission, mechanical ventilation duration, duration of ICU stay, 807 hospitalized paents in ICU 309 hospitalized less than 48 hours 498 eligible 242 Group PRE From May 1, 2011 to October 31, 2011 50 admied for thoracic surgery 192 Group PRE Aer exclusion of paents admied for thoracic surgery From May 1, 2011 to October 31, 2011
256 Group POST From November 1, 2011 to May 1, 2012 54 admied for thoracic surgery 202 Group POST Aer exclusion of paents admied for thoracic surgery From November 1, 2011 to May 1, 2012
Fig. 1. Study flowchart. ICU: intensive care unit.
duration of hospital stay, ICU mortality, and hospital mortality. The number of chest radiographs, the features of chest radiographs (emergent or elective), and the number of chest CT scans were collected. Statistical analysis was performed using R software version 2.13. Univariate analysis of before/after data was performed using Mann–Whitney and Chi2 tests. Data are expressed as medians and interquartiles or means and standard deviations. A value of P below 0.05 defined the significance. As chest radiographs or chest CT scans were often directly demanded by thoracic surgeons for personal use, a subgroup analysis was conducted after excluding the patients undergoing ICU after thoracic surgery. 2. Results As show in the flow chart of the study, 498 patients met the criteria for inclusion (Fig. 1). Medicine, surgery, and trauma were the causes of admission in 46%, 19%, and 35% of the cases, respectively The demographic features were similar in the two groups, with the exception of SAPS II (Table 1). The durations of mechanical ventilation, ICU stay, and hospital stay did not differ in the two groups. The ICU mortality rate was 21% in the group PRE, as compared with 22% in the group POST (P = 0.75) (Table 1). For each ICU stay, the absolute number of chest radiographs was 10.3 12.4 in the group PRE and 7.7 10.3 in the group POST, respectively (P < 0.0005) (Table 2). The effect was maximal in the last quarter (Fig. 2). Of note, the absolute number of unscheduled chest radiographs was similar in both groups (3.7 3.9 vs. 3.4 3.5, P = 0.27). With respect to chest CT scan, the number of procedures change 0.5 0.7 CT scan/ICU stay in the group PRE to 0.4 0.6 CT scan/ICU stay in the group POST (P = 0.01) (Table 2). After exclusion of 104 patients admitted to the ICU after thoracic surgery, the absolute number of chest radiographs (for Table 1 Characteristics of patients and outcome. Variables
PRE (n = 242)
POST (n = 256)
P
Age (years) Male (%) SAPS II Admission diagnosis, (%) Trauma patient Surgical patient Medical patient Duration of ICU stay (day) Duration of hospital stay (day) Duration of mechanical ventilation (day) ICU mortality (%) Hospital mortality (%)
54 [38–66] 182 (75) 32 [22–44]
56 [41–69] 177 (69) 36 [26–49]
0.11 0.15 0.005
96 (40) 51 (21) 95 (39) 5 [3–11] 20 [10–33] 1 [0–6]
79 (31) 41 (16) 136 (53%) 5 [3–10] 18 [10–31] 2 [0–7]
0.01 0.01 0.01 0.5 0.72 0.09
51 (21) 62 (25)
58 (22) 71 (27)
0.75 0.66
Results are expressed as median and interquartiles or absolute number and percentage. SAPS: simplified acute physiology score; ICU: Intensive care unit; PRE: before daily lung ultrasound implementation; POST: after daily lung ultrasound implementation.
Table 2 Number of chest radiographs and computed tomography (CT) scan during the intensive care unit (ICU) stay according to the study period (PRE: before daily lung ultrasound implementation; POST: after daily lung ultrasound implementation).
Number of chest radiograph/ICU stay Number of unscheduled chest radiograph/ICU stay Number of chest CT scan/ICU stay
PRE (n = 242)
POST (n = 256)
P
10.3 12.4 3.7 3.9
7.7 10.3 3.4 3.5
< 0.0005 0.27
0.5 0.7
0.4 0.6
0.01
Results are expressed as mean and standard derivation.
Please cite this article in press as: Zieleskiewicz L, et al. Implementation of lung ultrasound in polyvalent intensive care unit: Impact on irradiation and medical cost. Anaesth Crit Care Pain Med (2015), http://dx.doi.org/10.1016/j.accpm.2015.01.002
G Model
ACCPM-7; No. of Pages 4 L. Zieleskiewicz et al. / Anaesth Crit Care Pain Med xxx (2015) xxx–xxx
Fig. 2. Mean number of chest radiograph per patient per ICU stay, according to 3 months periods. Period 1 from May 1 to July 31, 2011. Period 2 from August 1 to October 31, 2011. Period 3 from November 1, 2011 to January 31, 2012. Period 4 from February 1 to May 1, 2012.
Table 3 Number of chest radiographs and computed tomography (CT) scan during the intensive care unit (ICU) stay according to the study period (PRE: before daily lung ultrasound implementation; POST: after daily lung ultrasound implementation) after exclusion of 104 patients admitted for thoracic surgery (postoperative care or complication).
Number of chest radiograph/ICU stay Number of chest CT scan/ICU stay
PRE (n = 192)
POST (n = 202)
P
9.4 11.0 0.6 1.0
6.4 8.0 0.4 1.0
0.0001 0.007
Results are expressed as mean and standard derivation.
each ICU stay) was 9.4 11.0 in the group PRE and 6.4 8.0 in the group POST, respectively (P = 0.0001). The number of CT scans was 0.6 1.0 in the group PRE versus 0.4 1.0 in the group POST (P = 0.007) (Table 3). 3. Discussion Our results show that the implementation of a ‘‘daily lung ultrasound round’’ was associated with a reduced use of routine chest radiographs and chest CT scans. One may extrapolate that this result was associated with reduced cost and decreased radiation exposure. In addition, one can expect that the reduced number of patient mobilizations may prevent harmful events. During the study, the ICU staff members were blinded about the study design. No specific protocol was implemented in order to reduce the radiation exposure. This means that our study strictly measured the effect of the daily lung ultrasound round, independently of protocols aimed at reducing radiation exposure. Our results, in line with a previous study [15], show that lung ultrasound facilitated the control of prescription of chest radiographs. However, in this previous study, ultrasound was only used for the detection of pleural effusion. In the present study, ultrasound served to identify both pleural and parenchyma pathologic entities. The number of chest radiographs decreased by 24% during the study period. This represents yearly around 1000 chest radiographs. In our ICU, the large use of chest radiograph is partly explained by a large number of trauma patients. The recourse to chest CT scan was reduced by 15%, representing 50 chest CT scans yearly. In terms of radiation, this corresponds to a 1050 mGy reduction, i.e. 1000 maximal annual doses. In our structure the respective costs of a chest radiograph and a chest CT scan are around 25 s and 130 s. Thus, we evaluated that the cost was
3
decreased by around 30,000 s/year i.e. about the cost of a small ultrasound machine. We noted a maximal effect during the late phase (last quarter) of our approach. The absolute prescription of chest radiographs did not significantly change after the first quarter of lung ultrasound implementation (period 3). This probably reflects the learning curve, and the time required for the appropriation of this technology [17]. For this period, chest radiographs were probably required in order to confirm the findings of ultrasound examination. This hypothesis was also suggested in a previous study [15]. The number of unscheduled chest radiographs did not change over the study period. Unscheduled chest radiographs may have been prescribed for device control or urgent clinical conditions. For device control, lung ultrasound can be an alternative to chest radiograph [21–23]. Nevertheless, in our study, lung ultrasound was not used in this indication. This probably explains the lack of decrease of their use. Similar finding was reported in a previous study [15]. With respect to the use of chest radiographs in urgent situation, this result can be related to a lack of confidence of physicians with ultrasound in patients with life-threatening conditions. Future prospective studies are required to confirm these results. Our findings are reinforced after the exclusion of patients admitted after thoracic surgery for postoperative care or complications. The surgical features may explain the need for chest radiograph. However, the chest radiograph probably facilitates the interface between members of different teams. In order to reduce the radiation exposure, there is a need to share basic knowledge on ultrasound between surgeons and intensivists. To this purpose, a short training of thoracic surgeons was implemented in our hospital. Future studies are required to evaluate the impact of this process. Our study has several limitations that we have to acknowledge. The retrospective design can induce a loss of information. However, we used data extracted from our electronic database, and the loss of information was minimal. In our unit, the prescription of chest radiographs is liberal. No formal written protocol has been implemented for reducing radiation exposure. This lack of protocol made it possible to measure the effect of the daily lung ultrasound round without altering the background noise during the study period. The study was performed in a single center, and a local effect may have impacted our findings. Due to the low number of CT scan/patient, we observed a large variability that can be regarded as a limitation. The increase number of trauma patients during the PRE period may have affected the results. However, there is no clear evidence showing that chest Xrays are more often used in trauma patients than in medical patients. Of more, patients in the POST period had a higher severity score. Finally, the performance of a lung ultrasound is timeconsumer, limiting the diffusion of this strategy in ICU with a large number of physicians. In conclusion, our study confirms that the introduction of a daily lung ultrasound round is associated with a decreased use of routine chest radiographs and chest CT scans. This strategy probably reduces the cost and radiation exposure. Of note, this result was obtained without altering patient outcome. The introduction of protocols formalizing the respective indications for each examination may increase this effect and remains to be tested in a multicenter and randomized clinical trial. Disclosure of interest The authors declare that they have no conflicts of interest concerning this article. Acknowledgments Authors thank Dr. F. Craighero and Dr. C. Arbelot for their help.
Please cite this article in press as: Zieleskiewicz L, et al. Implementation of lung ultrasound in polyvalent intensive care unit: Impact on irradiation and medical cost. Anaesth Crit Care Pain Med (2015), http://dx.doi.org/10.1016/j.accpm.2015.01.002
G Model
ACCPM-7; No. of Pages 4 L. Zieleskiewicz et al. / Anaesth Crit Care Pain Med xxx (2015) xxx–xxx
4
References [1] Fazel R, Krumholz HM, Wang Y, Ross JS, Chen J, Ting HH, et al. Exposure to lowdose ionizing radiation from medical imaging procedures. N Engl J Med 2009;27:849–57. [2] Brenner DJ, Hall EJ. Computed tomography: an increasing source of radiation exposure. N Engl J Med 2007;29:2277–84. [3] Rohner DJ, Bennett S, Samaratunga C, Jewell ES, Smith JP, Gaskill-Shipley M, et al. Cumulative total effective whole-body radiation dose in critically ill patients. Chest 2013;144:1481–6. [4] Voigt LP, Pastores SM, Raoof ND, Thaler HT, Halpern NA. Review of a large clinical series: intrahospital transport of critically ill patients: outcomes, timing, and patterns. J Intensive Care Med 2009;24:108–15. [5] Clec’h C, Simon P, Hamdi A, Hamza L, Karoubi P, Fosse JP, et al. Are daily routine chest radiographs useful in critically ill, mechanically ventilated patients? A randomized study. Intensive Care Med 2008;34:264–70. [6] Hendrikse KA, Gratama JW, Hove WT, Rommes JH, Schultz MJ, Sponk PE. Low value of routine chest radiographs in a mixed medical-surgical ICU. Chest 2007;132:823–8. [7] Graat ME, Choi G, Wolthuis EK, Korevaar JC, Sponk PE, Stoker J, et al. The clinical value of daily routine chest radiographs in a mixed medical-surgical intensive care unit is low. Crit Care 2006;10:R11. [8] Lichtenstein D, Goldstein I, Mourgeon E, Cluzel P, Grenier P, Rouby JJ. Comparative diagnostic performances of auscultation, chest radiography, and lung ultrasonography in acute respiratory distress syndrome. Anesthesiology 2004;100:9–15. [9] Bouhemad B, Zhang M, Lu Q, Rouby JJ. Clinical review: bedside lung ultrasound in critical care practice. Crit Care 2007;11:205. [10] Xirouchaki N, Magkanas E, Vaporidi K, Kondili E, Plataki M, Patrianakos A, et al. Lung ultrasound in critically ill patients: comparison with bedside chest radiography. Intensive Care Med 2011;37:1488–93. [11] Lichtenstein DA, Mezie`re G, Lascols N, Biderman P, Courret JP, Gepner A, et al. Ultrasound diagnosis of occult pneumothorax. Crit Care Med 2005;33: 1231–8. [12] Zanforlin A, Giannuzzi R, Nardini S, Testa A, Soldati G, Copetti R, et al. The role of chest ultrasonography in the management of respiratory diseases. Multidiscip Respir Med 2013;8:54. [13] Alrajhi K, Woo MY, Vaillancourt C. Test characteristics of ultrasonography for the detection of pneumothorax. Chest 2012;141:703–8. [14] Shankar H, Pagel PS. Potential adverse ultrasound-related biological effects: a critical review. Anesthesiology 2011;115:1109–24. [15] Peris A, Tutino L, Zagli G, Batacchi S, Cianchi G, Spina R, et al. The use of point-of-care bedside lung ultrasound significantly reduces the number
[16]
[17]
[18]
[19]
[20]
[21]
[22]
[23]
of radiographs and computed tomography scans in critically ill patients. Anesth Analg 2010;111:687–92. Volpicelli G, Elbarbary M, Blaivas M, Lichtenstein DA, Mathis G, Kirkpatrick AW, et al. International liaison committee on lung ultrasound (ILC-LUS) for international consensus conference on lung ultrasound (ICC-LUS). International evidence-based recommendations for point-of-care lung ultrasound. Intensive Care Med 2012;38:577–91. Tutino L, Cianchi G, Barbani F, Batacchi S, Cammelli R, Peris A. Time needed to achieve completeness and accuracy in bedside lung ultrasound reporting in intensive care unit. Scand J Trauma Resusc Emerg Med 2010;12:18–44. Zieleskiewicz L, Arbelot C, Hammad E, Brun C, Textoris J, Martin C, et al. Lung ultrasound: clinical applications and perspectives in intensive care unit. Ann Fr Anesth Reanim 2012;31:793–801. Bouhemad B, Brisson H, Le-Guen M, Arbelot C, Lu Q, Rouby JJ. Bedside ultrasound assessment of positive end-expiratory pressure induced lung recruitment. Am J Respir Crit Care Med 2011;183:341–7. Chalumeau-Lemoine L, Baudel JL, Das V, Arrive´ L, Noblinski B, Guidet B, et al. Results of short-term training of naı¨ve physicians in focused general ultrasonography in a intensive care unit. Intensive Care Med 2009;35:1767–71. Galbois A, Ait-Oufella H, Baudel JL, Kofman T, Bottero J, Viennot S, et al. Pleural ultrasound compared with chest radiographic detection of pneumothorax resolution after drainage. Chest 2010;138:648–55. Maury E, Guglielminotti J, Alzieu M, Guidet B, Offenstadt G. Ultrasonic examination: an alternative to chest radiography after central venous catheter insertion? Am J Respir Crit Care Med 2001;164:403–5. Vigneau C, Baudel JL, Guidet B, Offenstadt G, Maury E. Sonography as an alternative to radiography for nasogastric feeding tube location. Intensive Care Med 2005;31:1570–2.
Further reading Koegelenberg C, Von Groote-Bidlingmaier F, Bolliger CT. Transthoracic ultrasonography for the respiratory physician. Respiration 2012;84:337–50. Ioos V, Galbois A, Chalumeau-Lemoine L, Guidet B, Maury E, Hejblum G. An integrated approach for prescribing fewer chest X-rays in the ICU. Ann Intensive Care 2011;1:4. Nazerian P, Vanni S, Volpicelli G, Gigli C, Zanobetti M, Bartolucci M, et al. Accuracy of point-of-care multiorgan ultrasonography for the diagnosis of pulmonary embolism. Chest 2013;10:1087. Koenig S, Chandra S, Alaverdian A, Dibello C, Mayo PH, Narasimhan M. Ultrasound assessment of pulmonary embolism in patients receiving computerized tomography pulmonary angiography. Chest 2013;10:797.
Please cite this article in press as: Zieleskiewicz L, et al. Implementation of lung ultrasound in polyvalent intensive care unit: Impact on irradiation and medical cost. Anaesth Crit Care Pain Med (2015), http://dx.doi.org/10.1016/j.accpm.2015.01.002
