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Theophylline increases diaphragmatic contractility in mechanically ventilated newborns
Journal of Critical Care 37 (2017) 264–265
Contents lists available at ScienceDirect
Journal of Critical Care journal homepage: www.jccjournal.org
Theophylline increases diaphragmatic contractility in mechanically ventilated newborns Dear Editor, We read with interest the paper by Kim et al [1] about the “Effect of Theophylline on Ventilator-Induced Diaphragmatic Dysfunction.” Patients who required mechanical ventilation for at least 72 hours and had evidence of ventilator-induced diaphragmatic dysfunction by ultrasonography showed a significant improvement in diaphragmatic movements after theophylline administration compared with the control group [1]. As diaphragmatic function is a major determinant of successful weaning from mechanical ventilation, interventions aimed at improving respiratory muscle function may help to prevent postextubation respiratory failure [2]. Evaluating diaphragmatic dysfunction in neonates can be technically challenging. Particularly promising is noninvasive measurement of diaphragmatic electrical activity by a specialized nasogastric tube (Edi catheter) incorporated into a mechanical ventilator (Servo-I; Maquet, Solna, Sweden) [3]. The electrical activity of the diaphragm (Edi) is measured from an array of 8 bipolar electrodes inserted into the lower end of the nasogastric tube with sensors placed above the feeding holes and positioned in the lower esophagus at the level of the crural diaphragm. The electrical activity of the diaphragm is displayed both as waveforms and numerically on a breath-by-breath basis. For each breath, the highest Edi value of the waveform, the Edipeak, represents neural inspiratory effort, whereas the lowest Edi (Edimin) represents the spontaneous tonic activity of the diaphragm [3]. We prospectively collected data about 4 infants on prolonged mechanical ventilation and muscle paralysis who received 1 loading dose of theophylline at 8 mg/kg as an intravenous infusion over 20 minutes. Diaphragmatic electrical activity was measured by Edi catheter. Edipeak (μV) and Edimin (μV) were recorded every 60 seconds in the 30 minutes before and after theophylline administration. Data were reported as mean (standard deviation) (t test for independent samples) or median (interquartile range) (Mann-Whitney test) in case of normal or nonnormal distribution, respectively. The first patient was a male neonate born at 36 weeks’ gestational age, birth weight (BW) 3240 g, requiring prolonged high-frequency oscillatory ventilation (23 days) and muscle paralysis due to pneumothorax and pulmonary hypertension. The second infant was an ex-27 + 6 weeks’ gestational age twin male, BW 1166 g, with pulmonary hypertension secondary to bronchopulmonary dysplasia, requiring ventilation for 7 days due to respiratory failure at 126 days of life. The third case was a female term baby, BW 2995 g, requiring conventional ventilation for 7 days after surgery for bladder exstrophy. The fourth case was a term female infant requiring
0883-9441/© 2016 Elsevier Inc. All rights reserved.
mechanical ventilation for 8 days due to hypoxic respiratory failure secondary to meconium aspiration syndrome and septic shock. Diaphragm electric activity significantly improved after theophylline administration, as shown both by the amplitude of waveforms on the monitor screen (Fig. 1) and by numerical values of Edipeak and Edimin (patient 1: Edipeak μV from 7.3 (2.7) to 11.7 (3.2), P .0001, Edimin μV from 1.2 (0.5) to 2.1 (0.6), P b .0001; patient 2: Edipeak μV from 1.5 (1.2) to 7.5 (3.9), P b .0001, Edimin μV from 0.2 (0.1) to 0.9 (0.5), P .0002; patient 3: Edipeak μV from 1.4 (1.3-1.9) to 5.8 (2.9-13), P b .0001, Edimin μV from 0.3 (0.2-0.6) to 1.5 (0.7-2.6), P b .0001; patient 4: Edipeak μV from 2.9 (1.1) to 5.9 (1.8), P b .0001, Edimin μV from 0.5 (0.6) to 0.8 (0.7), P .09.). All patients were successfully weaned from mechanical ventilation and extubated within the subsequent 12 hours. Only 1 patient was reintubated because of upper airways obstruction. In our opinion, our series strengthens the authors conclusions that theophylline improves diaphragmatic activity. Moreover, we believe that monitoring continuously electrical diaphragmatic activity may add complementary useful clinical information and help to better understand theophylline effects.
Angela De Cunto⁎, Giulia Paviotti, Jenny Bua, Sergio Demarini, Division of Neonatology, Institute for Maternal and Child Health, IRCCS “Burlo Garofolo”, Trieste, Italy ⁎Corresponding author. Institute for Maternal and Child Health IRCCS “Burlo Garofolo”, Via dell'Istria 65/1, 34137, Trieste, Italy Tel.: +39 040 3785371; fax: +39 040 3785239 E-mail address: [email protected]
http://dx.doi.org/10.1016/j.jcrc.2016.10.001 References [1] Kim WY, Park SH, Kim WY, Huh JW, Hong SB, Koh Y, et al. Effect of theophylline on ventilator-induced diaphragmatic dysfunction. J Crit Care 2016;33: 145–50. [2] Jubran A. Critical illness and mechanical ventilation: effects on the diaphragm. Respir Care 2006;51(9):1054–61. [3] Stein H, Firestone K, Rimensberg PC. Synchronized mechanical ventilation using electrical activity of the diaphragm in neonates. Clin Perinatol 2012;39:525–42.
Letter / Journal of Critical Care 37 (2017) 264–265
Fig. 1. Diaphragmatic electrical activity (bottom waveform) before (A) and after (B) intravenous administration of theophylline.
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Contents lists available at ScienceDirect
Journal of Critical Care journal homepage: www.jccjournal.org
Theophylline increases diaphragmatic contractility in mechanically ventilated newborns Dear Editor, We read with interest the paper by Kim et al [1] about the “Effect of Theophylline on Ventilator-Induced Diaphragmatic Dysfunction.” Patients who required mechanical ventilation for at least 72 hours and had evidence of ventilator-induced diaphragmatic dysfunction by ultrasonography showed a significant improvement in diaphragmatic movements after theophylline administration compared with the control group [1]. As diaphragmatic function is a major determinant of successful weaning from mechanical ventilation, interventions aimed at improving respiratory muscle function may help to prevent postextubation respiratory failure [2]. Evaluating diaphragmatic dysfunction in neonates can be technically challenging. Particularly promising is noninvasive measurement of diaphragmatic electrical activity by a specialized nasogastric tube (Edi catheter) incorporated into a mechanical ventilator (Servo-I; Maquet, Solna, Sweden) [3]. The electrical activity of the diaphragm (Edi) is measured from an array of 8 bipolar electrodes inserted into the lower end of the nasogastric tube with sensors placed above the feeding holes and positioned in the lower esophagus at the level of the crural diaphragm. The electrical activity of the diaphragm is displayed both as waveforms and numerically on a breath-by-breath basis. For each breath, the highest Edi value of the waveform, the Edipeak, represents neural inspiratory effort, whereas the lowest Edi (Edimin) represents the spontaneous tonic activity of the diaphragm [3]. We prospectively collected data about 4 infants on prolonged mechanical ventilation and muscle paralysis who received 1 loading dose of theophylline at 8 mg/kg as an intravenous infusion over 20 minutes. Diaphragmatic electrical activity was measured by Edi catheter. Edipeak (μV) and Edimin (μV) were recorded every 60 seconds in the 30 minutes before and after theophylline administration. Data were reported as mean (standard deviation) (t test for independent samples) or median (interquartile range) (Mann-Whitney test) in case of normal or nonnormal distribution, respectively. The first patient was a male neonate born at 36 weeks’ gestational age, birth weight (BW) 3240 g, requiring prolonged high-frequency oscillatory ventilation (23 days) and muscle paralysis due to pneumothorax and pulmonary hypertension. The second infant was an ex-27 + 6 weeks’ gestational age twin male, BW 1166 g, with pulmonary hypertension secondary to bronchopulmonary dysplasia, requiring ventilation for 7 days due to respiratory failure at 126 days of life. The third case was a female term baby, BW 2995 g, requiring conventional ventilation for 7 days after surgery for bladder exstrophy. The fourth case was a term female infant requiring
0883-9441/© 2016 Elsevier Inc. All rights reserved.
mechanical ventilation for 8 days due to hypoxic respiratory failure secondary to meconium aspiration syndrome and septic shock. Diaphragm electric activity significantly improved after theophylline administration, as shown both by the amplitude of waveforms on the monitor screen (Fig. 1) and by numerical values of Edipeak and Edimin (patient 1: Edipeak μV from 7.3 (2.7) to 11.7 (3.2), P .0001, Edimin μV from 1.2 (0.5) to 2.1 (0.6), P b .0001; patient 2: Edipeak μV from 1.5 (1.2) to 7.5 (3.9), P b .0001, Edimin μV from 0.2 (0.1) to 0.9 (0.5), P .0002; patient 3: Edipeak μV from 1.4 (1.3-1.9) to 5.8 (2.9-13), P b .0001, Edimin μV from 0.3 (0.2-0.6) to 1.5 (0.7-2.6), P b .0001; patient 4: Edipeak μV from 2.9 (1.1) to 5.9 (1.8), P b .0001, Edimin μV from 0.5 (0.6) to 0.8 (0.7), P .09.). All patients were successfully weaned from mechanical ventilation and extubated within the subsequent 12 hours. Only 1 patient was reintubated because of upper airways obstruction. In our opinion, our series strengthens the authors conclusions that theophylline improves diaphragmatic activity. Moreover, we believe that monitoring continuously electrical diaphragmatic activity may add complementary useful clinical information and help to better understand theophylline effects.
Angela De Cunto⁎, Giulia Paviotti, Jenny Bua, Sergio Demarini, Division of Neonatology, Institute for Maternal and Child Health, IRCCS “Burlo Garofolo”, Trieste, Italy ⁎Corresponding author. Institute for Maternal and Child Health IRCCS “Burlo Garofolo”, Via dell'Istria 65/1, 34137, Trieste, Italy Tel.: +39 040 3785371; fax: +39 040 3785239 E-mail address: [email protected]
http://dx.doi.org/10.1016/j.jcrc.2016.10.001 References [1] Kim WY, Park SH, Kim WY, Huh JW, Hong SB, Koh Y, et al. Effect of theophylline on ventilator-induced diaphragmatic dysfunction. J Crit Care 2016;33: 145–50. [2] Jubran A. Critical illness and mechanical ventilation: effects on the diaphragm. Respir Care 2006;51(9):1054–61. [3] Stein H, Firestone K, Rimensberg PC. Synchronized mechanical ventilation using electrical activity of the diaphragm in neonates. Clin Perinatol 2012;39:525–42.
Letter / Journal of Critical Care 37 (2017) 264–265
Fig. 1. Diaphragmatic electrical activity (bottom waveform) before (A) and after (B) intravenous administration of theophylline.
265