|Year : 2018 | Volume
| Issue : 2 | Page : 165-169
Effect of positive end-expiratory pressure on optic nerve sheath diameter in pediatric patients with traumatic brain injury
Ankur Khandelwal, Indu Kapoor, Charu Mahajan, Hemanshu Prabhakar
Department of Neuroanesthesiology and Critical Care, Neuroscience Center, All India Institute of Medical Sciences (AIIMS), New Delhi, India
|Date of Web Publication||5-Jul-2018|
Department of Neuroanesthesiology and Critical Care, Neuroscience Center, All India Institute of Medical Sciences (AIIMS), New Delhi
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Background: The peak incidence of traumatic brain injury (TBI) has been reported in children and young adults. Intracranial pressure (ICP) as an important component can be measured with invasive technique, whereas noninvasive measurement of optic nerve sheath diameter (ONSD) is increasingly becoming popular. Positive end-expiratory pressure (PEEP) has been found to affect ICP. We aimed to compare the effect of different values of PEEP on ONSD and to obtain the correlation with ICP measurement. Setting and Design: Neurointensive Care Unit, Trauma Center, AIIMS, New Delhi. Materials and Methods: Pediatric patients with TBI, of either gender, between 1 and 18 years of age in whom ICP was measured using intraparenchymal Codman catheter admitted in neurointensive care unit were enrolled. For this crossover study, the sequence of PEEP (0 or 3 or 5cm H2O) was randomized and ONSD was measured. The mean of three ONSD values was taken as final value. Statistical Method: The ONSD, ICP, peak airway pressure, and hemodynamic parameters at various stages were compared using two-way repeated measures analysis of variance with Bonferroni correction. A P value of <0.05 was considered to be significant. Results: Ten patients (seven males, three females) participated in the study. There was no significant increase in ONSD values when PEEP was increased from 0 to 3cm H2O. However, increase in PEEP values from 3 to 5cm H2O showed significantly increased ONSD values. Conclusion: PEEP up to 3cm H2O can be safely applied in pediatric patients following TBI. Further increment of PEEP might accentuate the ICP values.
Keywords: Intracranial pressure, optic nerve sheath diameter, positive end-expiratory pressure
|How to cite this article:|
Khandelwal A, Kapoor I, Mahajan C, Prabhakar H. Effect of positive end-expiratory pressure on optic nerve sheath diameter in pediatric patients with traumatic brain injury. J Pediatr Neurosci 2018;13:165-9
|How to cite this URL:|
Khandelwal A, Kapoor I, Mahajan C, Prabhakar H. Effect of positive end-expiratory pressure on optic nerve sheath diameter in pediatric patients with traumatic brain injury. J Pediatr Neurosci [serial online] 2018 [cited 2022 Jan 23];13:165-9. Available from: https://www.pediatricneurosciences.com/text.asp?2018/13/2/165/235931
| Introduction|| |
Traumatic brain injury (TBI) is a major cause of disability, death, and economic cost to our society. The peak incidence has consistently been reported in children and young adults. However, over the last 30 years, there has been a declining trend in mortality from 50% to 25% due to the systematic use of evidence-based protocols that emphasize monitoring and maintain adequate cerebral perfusion., Protocols that emphasize intracranial pressure (ICP) monitoring have demonstrated improved outcomes particularly in trauma centers., More recently, advancement in the field of research has enabled the diagnosis of raised ICP much reliably by noninvasive modalities. One such noninvasive modality includes estimation of optic nerve sheath diameter (ONSD) using bedside ultrasound.
The optic nerve sheath is an anatomical extension of the dura mater and the subarachnoid space around the optic nerve is continuous with the intracranial subarachnoid space. The anterior part of the optic nerve is loosely attached to the dural sheath and is surrounded only by orbital fat, thus making it distensible. Because of this direct communication, pressure changes in the intracranial compartment are transmitted to the intraorbital (particularly retrobulbar) subarachnoid space around the optic nerve. Dilatation of optic nerve sheath has been shown to be a much earlier manifestation of ICP rise.,,, Ultrasound technology using high-frequency linear probes (>7.5 MHz) with improved spatial resolution has enabled excellent views of the optic nerve sheath.
Severe TBI is accompanied by both neurological and non-neurological complications. Involvement of respiratory system in the form of acute lung injury (ALI, 20%) and acute respiratory distress syndrome (ARDS, 10%) leading to hypoxemia is not uncommon after severe TBI and warrants early intervention., One of the established ventilation strategies to improve oxygenation index in lung injury is by recruiting collapsed alveoli through application of high positive end-expiratory pressure (PEEP). However, high PEEP therapy in adult patients with severe TBI has been shown to increase ICP and compromise cerebral perfusion pressure (CPP). Because of the lack of availability of literatures pertaining to the effect of PEEP on ICP in pediatric patients, optimal PEEP is yet to be ascertained.
The primary aim of our study was to compare the effect of different values of PEEP on ONSD and to obtain the correlation with ICP measurement. The secondary aim was to simultaneously evaluate the effect of similar values of PEEP on peak airway pressure (PAP), heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), and mean blood pressure (MBP).
| Materials and Methods|| |
After approval from the Institutional Ethics Committee and written informed consent obtained from parents, we enrolled 10 pediatric patients with TBI, of either gender, between 1 and 18 years of age admitted in neurointensive care unit. For this crossover study, the sequence of PEEP (0 or 3 or 5cm H2O) was randomized using computer-generated program. This observational study was conducted over a period of 3 months. We included only those patients in whom ICP was measured using intraparenchymal Codman catheter. We excluded patients with associated respiratory or cardiovascular system disease or hemodynamically unstable patients. Patients with less than 1 year of age or more than 18 years of age were also excluded from the study. ONSD was measured using a 6- to 13-MHz linear probe of the ultrasound machine. The patients were placed in supine position with head-up tilt of 30°. Eyes were covered with transparent plaster. A water-soluble ultrasound-transmission jelly was applied over the probe. The probe was gently placed over the eyelid paying careful attention not to exert excessive pressure. The probe was adjusted from temporal to nasal end to find a suitable angle for displaying the entrance of optic nerve into the globe. The optic nerve was focused in the center of the image for measurement. The ONSD was measured 3mm behind the globe. The ONSD was measured at PEEP values of 0, 3, and 5cm H2O. Simultaneously, invasive ICP values were also recorded at all these three PEEP values. The ONSD was measured 3min after achieving desired PEEP value. We took three readings of ONSD and ICP at each PEEP setting, and mean of three values was taken as the final value. The average ONSD and ICP values were measured by an independent observer, who was blinded to ventilation setting. Other variables such as PAP, HR, SBP, DBP, and MBP were also recorded.
All the patients were mechanically ventilated with the following settings: mode, synchronized intermittent mandatory ventilation (SIMV); fraction of inspired oxygen (FiO2), 0.4; square wave, inspiratory-expiratory ratio (I/E), 1:2; tidal volume (TV, 8mL/kg); and respiratory rate set to keep the partial pressure of carbon dioxide (PaCO2) at 34–36 mmHg. Factors such as position of the patient, time of estimation of ONSD after achieving desired PEEP, and measuring ONSD in a single plain (transverse) and involving two experienced observers in ONSD measurement were kept constant to minimize confounding factors.
Data were analyzed using software STATA 9.0 (StataCorp, College Station, TX). Data are expressed as median (range) or mean (SD) or number (%) as appropriate. The ONSD, ICP, PAP, and hemodynamic parameters at various stages were compared using two-way repeated measures analysis of variance with Bonferroni correction. A P value of <0.05 was considered to be significant.
| Results|| |
On the basis of statistical analysis, the median age, weight, Glasgow Coma Scale (GCS), and number of intensive care unit (ICU) days of all 10 patients were calculated and have been tabulated [Table 1]. Of 10 patients, 7 were males and 3 were females. Only noticeable variable was the median GCS (6) implying the severity of TBI. [Table 2] shows the mean (SD) of all the hemodynamic variables at all the three levels of PEEP. Hemodynamic parameters such as HR, SBP, DBP, and MBP remained comparable to baseline values during sequential increase of PEEP from 0 to 3 and 3 to 5cm H2O.,
Although the median ONSD increased with sequential increase in PEEP, there was no significant increase in ONSD values when PEEP was increased from 0 to 3cm H2O (P = 0.183). However, increase in PEEP values from 3 to 5cm H2O showed significantly increased ONSD values (P = 0.000). Similarly, the ICP values showed no significant increase when PEEP increased from 0 to 3cm H2O (P = 0.417) but showed significant increase when PEEP increased from 3 to 5cm H2O (P = 0.001). PAP increased significantly during increment of PEEP both from 0 to 3cm H2O (P = 0.001) and from 3 to 5cm H2O (P = 0.000) [Table 3].
| Discussion|| |
TBI is classified as, either closed or penetrating (open). It is defined as any traumatically induced structural injury or physiological disruption of brain function as a result of an external force. Non-neurological organ dysfunction in severe TBI most commonly involves respiratory system, of which ALI and ARDS are the most severe and are associated with worse neurological outcomes and longer hospitalization., PEEP plays an important role in the ventilation management of ALI/ARDS because it improves oxygenation by recruiting small airways and collapsed alveoli, increases functional residual capacity, and decreases the incidence of ventilator-induced lung injury. Studies addressing the effect of PEEP on the intracranial system have focused mainly on ICP, showing conflicting results.,,,, It is still a matter of debate worldwide as to what should be the maximum level of PEEP that can correct hypoxemia without escalating ICP in patients with severe TBI. Although, there are few studies available in the literature defining the optimal PEEP in adult patients, there are none pertaining to pediatric patients with TBI.
According to Cooper et al., a PEEP value of 10cm H2O slightly increased ICP and was clinically safe for adult patients with severe TBI. In a pilot study conducted by Nemer et al. in 20 patients with severe TBI, PEEP application even up to 15cm H2O did not significantly increase ICP or decrease CPP. Similarly, Frost found no change in ICP even with PEEP as high as 40cm H2O. On the contrary, Shapiro and Marshall observed an ICP increase of 10mm Hg or more after the administration of 4–8cm H2O of PEEP along with a CPP decrease in 50% of the cases. In a study conducted by Videtta et al., PEEP was raised from 5 (basal) to 15cm H2O in steps of 5cm H2O. They observed that PEEP at 10 and 15cm H2O produced a significant increase in ICP without change in CPP. McGuire et al. postulated that ICP increase following PEEP administration of 10cm H2O or more occurs in patients with normal ICP but is well tolerated in patients with intracranial hypertension. This suggests that intracranial hypertension, by compressing the cerebral venous system, may avoid the transmission of intrathoracic pressure to the intracranial compartment.
Ours is the first study to determine the effect of three sequentially increasing PEEP values (0, 3, and 5cm H2O) primarily on ONSD in children with severe TBI. In this study, we also measured ICP invasively. Our results showed that both ONSD and ICP did not increase significantly when PEEP increased from 0 to 3cm H2O though the increase was significant when PEEP increased from 3 to 5cm H2O. However, this significant increase in ICP did not apparently change the clinical status. It would be unjustifiable to compare the results of our study with those conducted previously in adults because of significant differences in intracranial dynamics and autoregulation among the two populations. In a study conducted by Pulitanò et al. in 21 pediatric patients undergoing surgery for intracranial neoplasm, they did not find any significant difference in ICP values after increasing PEEP from 0 to 8cm H2O. This can probably be attributed to the chronic nature of the disease itself where the intracranial compensatory mechanisms reinforce over the time in contrast to acute and severe brain injury following trauma where the autoregulatory mechanisms are completely at stake.
Simultaneously, the effect of these three sequentially increasing PEEP values did not show any significant difference in the values of HR, SBP, DBP, and MBP. However, PAP values showed significant increase during increase of PEEP values both from 0 to 3cm H2O and then from 3 to 5cm H2O. Although the median PAP increased from 11.5 (PEEP, 0) to 15cm H2O (PEEP, 5), no complications pertaining to this increase could be noticed. This is because large changes in the intrathoracic pressure in children are accompanied by only small changes in chest wall pressure due to steep volume–pressure relationship. As such, large changes in ventilator pressure have only a limited effect on pleural pressure. This explains the generally higher cardiovascular tolerance of children to the application of high airway pressures.
Our study has few limitations. First, the study is limited by its small size and results need to be validated in larger population. Second, we did not measure CPP that indeed is a more robust determinant of cerebral autoregulation. Third, we did not measure compliance of the respiratory system, which according to literature is one of the main factors affecting the transmission of PEEP to the intracranial compartment. Fourth, we did not investigate the effect of PEEP in children with high ICP because the median ICP in these patients is not elevated. Fifth, because our patients had severe TBI (median GCS, 6), we feel that the results might have varied in patients with mild-to-moderate TBI, and thus further studies should categorize the patients into the three types of TBI. Finally, we also did not look for any specific adverse effects such as increased cerebral edema or intracranial bleeding pertaining to increased ICP, even though apparently there was no change in clinical status.
| Conclusion|| |
Thus, we conclude that, if required, PEEP up to 3cm H2O can be safely applied in pediatric patients following TBI. Further increment of PEEP might further improve oxygenation but at the cost of accentuation of ICP. At present, it is difficult to comment whether such increment of ICP resulting from PEEP application has any bearing on clinical outcome. Large trials are required to further validate the effect of PEEP on ICP in pediatric patients with TBI.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
| References|| |
Tagliaferri F, Compagnone C, Korsic M, Servadei F, Kraus J. A systematic review of brain injury epidemiology in Europe. Acta Neurochir (Wien) 2006;13:255-68.
Lu J, Marmarou A, Choi S, Maas A, Murray G, Steyerberg EW; Impact and Abic Study Group. Mortality from traumatic brain injury. Acta Neurochir Suppl 2005;13:281-5.
Hesdorffer DC, Ghajar J, Iacono L. Predictors of compliance with the evidence-based guidelines for traumatic brain injury care: A survey of United States trauma centers. J Trauma 2002;13:1202-9.
Bulger EM, Nathens AB, Rivara FP, Moore M, MacKenzie EJ, Jurkovich GJ; Brain Trauma Foundation. Management of severe head injury: Institutional variations in care and effect on outcome. Crit Care Med 2002;13:1870-6.
Lane PL, Skoretz TG, Doig G, Girotti MJ. Intracranial pressure monitoring and outcomes after traumatic brain injury. Can J Surg 2000;13:442-8.
Soldatos T, Karakitsos D, Chatzimichail K, Papathanasiou M, Gouliamos A, Karabinis A. Optic nerve sonography in the diagnostic evaluation of adult brain injury. Crit Care 2008;13:R67.
Blaivas M, Theodoro D, Sierzenski PR. Elevated intracranial pressure detected by bedside emergency ultrasonography of the optic nerve sheath. Acad Emerg Med 2003;13:376-81.
Rajajee V, Vanaman M, Fletcher JJ, Jacobs TL. Optic nerve ultrasound for the detection of raised intracranial pressure. Neurocrit Care 2011;13:506-15.
Hansen HC, Helmke K. Validation of the optic nerve sheath response to changing cerebrospinal fluid pressure: Ultrasound findings during intrathecal infusion tests. J Neurosurg 1997;13:34-40.
Bratton SL, Davis RL. Acute lung injury in isolated traumatic brain injury. Neurosurgery 1997;13:707-2.
Contant CF, Valadka AB, Gopinath SP, Hannay HJ, Robertson CS. Adult respiratory distress syndrome: A complication of induced hypertension after severe head injury. J Neurosurg 2001;13:560-8.
Mercat A, Richard JC, Vielle B, Jaber S, Osman D, Diehl JL, et al
.; Expiratory Pressure (Express) Study Group. Positive end-expiratory pressure setting in adults with acute lung injury and acute respiratory distress syndrome: A randomized controlled trial. JAMA 2008;13:646-55.
Shapiro HM, Marshall LF. Intracranial pressure responses to PEEP in head-injured patients. J Trauma 1978;13:254-6.
Blyth BJ, Bazarian JJ. Traumatic alterations in consciousness: Traumatic brain injury. Emerg Med Clin North Am 2010;13:571-94.
Zygun DA, Kortbeek JB, Fick GH, Laupland KB, Doig CJ. Non-neurologic organ dysfunction in severe traumatic brain injury. Crit Care Med 2005;13:654-60.
Holland MC, Mackersie RC, Morabito D, Campbell AR, Kivett VA, Patel R, et al
. The development of acute lung injury is associated with worse neurologic outcome in patients with severe traumatic brain injury. J Trauma 2003;13:106-11.
Cooper KR, Boswell PA, Choi SC. Safe use of PEEP in patients with severe head injury. J Neurosurg 1985;13:552-5.
Nemer SN, Caldeira JB, Santos RG, Guimarães BL, Garcia JM, Prado D, et al
. Effects of positive end-expiratory pressure on brain tissue oxygen pressure of severe traumatic brain injury patients with acute respiratory distress syndrome: A pilot study. J Crit Care 2015;13:1263-6.
Frost EA. Effects of positive end-expiratory pressure on intracranial pressure and compliance in brain-injured patients. J Neurosurg 1977;13:195-200.
Videtta W, Villarejo F, Cohen M, Domeniconi G, Santa Cruz R, Pinillos O, et al
. Effects of positive end-expiratory pressure on intracranial pressure and cerebral perfusion pressure. Acta Neurochir Suppl 2002;13:93-7.
McGuire G, Crossley D, Richards J, Wong D. Effects of varying levels of positive end-expiratory pressure on intracranial pressure and cerebral perfusion pressure. Crit Care Med 1997; 13:1059-62.
Pulitanò S, Mancino A, Pietrini D, Piastra M, De Rosa S, Tosi F, et al
. Effects of positive end expiratory pressure (PEEP) on intracranial and cerebral perfusion pressure in pediatric neurosurgical patients. J Neurosurg Anesthesiol 2013;13:330-4.
Kaditis AG, Motoyama EK, Zin W, Maekawa N, Nishio I, Imai T, et al
. The effect of lung expansion and positive end-expiratory pressure on respiratory mechanics in anesthetized children. Anesth Analg 2008;13:775-85.
Caricato A, Conti G, Della Corte F, Mancino A, Santilli F, Sandroni C, et al
. Effects of PEEP on the intracranial system of patients with head injury and subarachnoid hemorrhage: The role of respiratory system compliance. J Trauma 2005;13:571-6.
[Table 1], [Table 2], [Table 3]
|This article has been cited by|
||Effect of Respiratory Physiological Changes on Optic Nerve Sheath Diameter and Cerebral Oxygen Saturation in Patients With Acute Traumatic Brain Injury
| ||Sweatha Balakrishnan, Shwetha Naik, Dhritiman Chakrabarti, Subhas Konar, Kamath Sriganesh |
| ||Journal of Neurosurgical Anesthesiology. 2022; 34(1): e52 |
|[Pubmed] | [DOI]|
||Optimal positive end-expiratory pressure to prevent anaesthesia-induced atelectasis in infants
| ||Sujung Park, Jae Hoon Lee, Hyun Joo Kim, Haegi Choi, Jeong-Rim Lee |
| ||European Journal of Anaesthesiology. 2021; 38(10): 1019 |
|[Pubmed] | [DOI]|