High Concentration Oxygen for Pneumocephalus After Evacuation of Chronic Subdural Haematoma (HOPE)

High Concentration of Inspired Oxygen for Pneumocephalus After Evacuation of Chronic Subdural Haematoma: A Randomized Controlled Trial (HOPE Study)

Normobaric oxygen therapy was shown to be effective in reducing post craniotomy pneumocephalus. Theoretical assessment of normobaric oxygen therapy in treating pneumocephalus has shown that a higher level of oxygen concentration will significantly decrease the time for absorption of pneumocephalus. The therapeutic efficacy is not fully established in patients with chronic subdural hematoma after burr hole drainage. Both radiological outcomes and clinical outcomes would be evaluated.

Study Overview

• Status: Recruiting
• Conditions: Recurrence; Chronic Subdural Hematoma; Oxycephaly
• Intervention / Treatment: Procedure: High concentration Oxygen therapy; Procedure: Control: Room Air or Low concentration Oxygen

Detailed Description

Chronic subdural hematoma (CSDH) is not a benign disease. Morbidity and mortalities were high especially in those with recurrence requiring reoperations. The use of subdural drain after burr hole drainage is an excellent example demonstrating that by reducing CSDH recurrence, a significant improvement in functional outcomes can be observed.

Pneumocephalus is very common after burr hole drainage for CSDH. The use of high-flow oxygen had been reported to be effective in small case series, showing effectiveness in clinical and radiological outcomes. However, no large, prospective, controlled trial has been conducted to establish the efficacy of oxygen therapy on functional outcomes for patients with pneumocephalus after burr hole drainage in CSDH.

Bilateral CSDH has a different prognosis and is associated with a poorer outcome.

In addition to treating pneumocephalus, the use of perioperative oxygen has been suggested to minimize tissue hypoxemia and infection. In a study published in the New England Journal of Medicine, the use of perioperative supplementary oxygen was shown to reduce surgical site infection.

Hyperoxia with oxygen therapy has shown to be safe with minimal changes to the cerebral blood flow (CBF) from functional magnetic resonance imaging (fMRI).

Research Questions

1. Does post-operative high-flow oxygen improve pneumocephalus in terms of volume reduction in CSDH patients after burr-hole drainage?
2. Does post-operative high-flow oxygen reduce the recurrence rate of CSDH (radiologically) if pneumocephalus volume is reduced after oxygen therapy?
3. Does post-operative high-flow oxygen reduce the recurrence rate of CSDH (clinically), as defined by symptomatic recurrence requiring reoperation, if pneumocephalus volume is reduced after oxygen therapy?
4. Does post-operative high-flow oxygen improve CSDH patients' functional outcome in terms of modified Rankin Scale (mRS) at 3 months and 6 months?

Hypothesis Oxygen therapy for CSDH patients with post-operative pneumocephalus will experience significant resorption of intracranial air within 24 hours. There is a reduction in recurrence rate in terms of the re-operation rates. There is an improvement in functional outcome in terms of mRS.

Aim of the Study To evaluate changes in pneumocephalus volume and functional outcome after oxygen therapy in post-operative CSDH patients treated by burr hole drainage, as compared to the standard care by breathing in room air or low concentration oxygen during the post-operative period.

Study Design Prospective randomized 1:1 parallel-arm study

Methods and Randomization Patients will be recruited when they are considered fit for oxygen therapy as determined by the treating clinician. The timing of burr hole evacuation may vary according to the availability of the emergency operative time slot. The index intervention is postoperative oxygen therapy: 100% normobaric oxygen through a nonrebreather mask (NRM) at 12-15 Litre/minute consecutively for 24 hours. Removal of the nonrebreather mask is allowed during meals or other activities such as physiotherapy. The duration of mask removal would be documented. Compliance with NRM is considered to be good if the mask is kept > 90% of the time during the 24 hours treatment period. The reference intervention is standard post-operative care: the patient would be breathing in normobaric room air. For the reference arm, if the patient has desaturation (i.e. SaO2 < 93%), supplemental O2 therapy can be given to keep SaO2 > 93%. Arterial blood gas would be obtained by the clinicians when deemed necessary. If there is a significant deviation from the study protocol occurs, the patients will be analyzed according to their originally assigned groups (intention-to-treat principle).

Non-rebreather masks, when they are tightly applied, are associated with a lower aerosol dispersion distance (as compared to non-invasive positive pressure ventilation or venturi masks).

Interim data analysis would be performed and the study would be terminated if a significant difference in the primary outcome is observed.

• Study Type: Interventional
• Enrollment (Anticipated): 36
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: David YC Chan, MBBS, FRCS; Phone Number: 852-35052624; Email: david.yc.chan@cuhk.edu.hk
• Study Contact Backup: Name: Wai S Poon, MBChB, FRCS; Phone Number: 852-35051316; Email: wpoon@surgery.cuhk.edu.hk

Study Locations

• Hong Kong
  • Hong Kong, Hong Kong, 852
    • Recruiting
    • Division of Neurosurgery, Department of Surgery, Prince of Wales Hospital, The Chinese University of Hong Kong
    • Contact: David YC Chan, MBBS, FRCS; Phone Number: 2542 35052542; Email: david.yc.chan@cuhk.edu.hk
    • Contact: Wai Poon, MBChB, FRCS; Phone Number: 35051316; Email: wpoon@surgery.cuhk.edu.hk
    • Sub-Investigator: Wai S Poon, MBChB, FRCS
    • Sub-Investigator: Stephanie CP Ng, MPhil, PhD
    • Sub-Investigator: Danny TM Chan, MBChB, FRCS
    • Sub-Investigator: George KC Wong, MD, FRCS

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 14 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

1. Age greater than or equal to 18 years-old.
2. Presence of chronic subdural haematoma (CSDH) as diagnosed radiologically either by computed tomography (CT) brain scan or magnetic resonance imaging (MRI).
3. Treatment of CSDH by burr-hole evacuation.
4. Presence of post-operative pneumocephalus, as evidenced from post-operative CT Brain or MRI brain
5. Negative test to SARS-nCoV-2, as evidenced by either deep throat saliva rapid test, deep throat saliva PCR test, nasopharyngeal swab real-time PCR test, or nasopharyngeal swab rapid test within seven days.

Exclusion Criteria:

1. Presence of pre-existing respiratory conditions such as chronic obstructive pulmonary disease (COPD) and hence not suitable for oxygen therapy.
2. Any pre-existing illness that renders the patient moderately or severely disabled before diagnosis with CSDH, such as a history of central nervous system infection.
3. CSDH arising from secondary causes, such as intracranial hypotension, thrombocytopenia, etc.
4. Any evidence or suspicion that there is communication between the pneumocephalus with the air cells (e.g. such as mastoid air cells) or air sinuses (e.g. frontal sinus).
5. Patients that need an additional procedure e.g. epidural blood patch, etc.
6. Complications arising from the burr-hole operation or subdural drain insertion such as hemorrhage or surgical site infection requiring surgical intervention or deemed to affect the patient's long-term functional outcome.
7. Patients already on long-term steroid for pre-existing medical conditions.
8. Participation in other clinical trials within four weeks upon recruitment.
9. Pregnancy or on breastfeeding.
10. Any other reasons that the researchers consider the patients to be unsuitable.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: High concentration Oxygen Therapy; 12-15 Litre/min O2 delivery via Non-Rebreather Mask (NRM) consecutively for 24 hours.	Procedure: High concentration Oxygen therapy; FiO2 >80% Oxygen (Delivered with 12-15L/min Non-rebreather Mask)
Placebo Comparator: Room air or low concentration oxygen; Room air or low concentration oxygen (0-2 Litre/min O2 ) consecutively for 24 hours.	Procedure: Control: Room Air or Low concentration Oxygen; FiO2 <30% Oxygen (Delivered with 0-2L/min Nasal Cannula)

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Changes in the volume of pneumocephalus after 24 hours of oxygen therapy	Volumetric measurement of pneumocephalus from Computed Tomographic (CT) scan for the Head	24 hours

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Modified Rankins Scale (mRS)	Functional outcomes	at baseline before admission, on admission, at 1 month, at 3 months and at 6 months.
EuroQOL EQ-5D	Functional outcomes	at 1 month, at 3 months and at 6 months.
Glasgow Coma Scale (GCS)	Neurological examination	On admission, at 1 month, at 3 months and at 6 months.
Recurrence rate, as defined by reoperation rate due to symptomatic recurrence	Surgical complications	Reoperation rate within six months, including the number of re-operations for CSDH during the same admission episode, as well as subsequent readmission for reoperation for CSDH.
Changes in brain volume re-expansion	Volumetric measurement from Computed Tomographic (CT) scan for the Head	after 24 hours of oxygen therapy and 1 week after oxygen therapy
Changes in volume of subdural fluid	Volumetric measurement from Computed Tomographic (CT) scan for the Head	Recurrence or re-accumulation rate, as measured by an increase in subdural fluid volume at 1 week, 1 month, 3 months, and at 6 months.
Incidence of superficial wound infection	Surgical complications	Any surgically associated would infections within 6 months from the index operation
Incidence of deep wound infection, including subdural empyema	Surgical complications	Any surgically associated would infections within 6 months from the index operation
Incidence of chest complications, including chest infection	Complications	Any complications within the same admission episode for the index operation
Any complications arising from the Oxygen therapy (Adverse events)	Complications	Any complications within the same admission episode for the index operation
Barthel Index	Functional outcome	at 1 month, 3 months and 6 months
PaO2 and PaCO2 from the arterial blood gas (ABG)	Blood taking for ABG when judged to be necessary by the treating physician or when there is desaturation to SaO2 < 93%	During oxygen therapy
Duration of stay at the acute neurosurgical ward (LOS)	LOS	During the same admission episode for the index operation
Discharge destination	Outcome	Upon the same admission episode for the index operation
The length of stay in secondary care	LOS	Upon transferal to the secondary care from the same admission episode for the index operation
Mortality rate at 30 days, 3 months and 6 months.	Death rate	at 30 days, 3 months and 6 months.

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Recurrence rate in BILATERAL Chronic Subdural Hematoma (CSDH)	Bilateral (CSDH)	Within six months from the index operation
Volumetric reduction in pneumocephalus in BILATERAL Chronic Subdural Hematoma (CSDH) after Oxygen therapy	Bilateral (CSDH)	Within 24 hours after Oxygen therapy
Improvement in mRS for BILATERAL Chronic Subdural Hematoma (CSDH)	Functional outcome in bilateral CSDH	at 1 month, 3 months and 6 months

Collaborators and Investigators

• Sponsor: Chinese University of Hong Kong
• Investigators: Principal Investigator: David YC Chan, MBBS, FRCS, Chinese University of Hong Kong; Study Chair: Wai S Poon, MBChB, FRCS, Chinese University of Hong Kong

Publications and helpful links

General Publications

• Gore PA, Maan H, Chang S, Pitt AM, Spetzler RF, Nakaji P. Normobaric oxygen therapy strategies in the treatment of postcraniotomy pneumocephalus. J Neurosurg. 2008 May;108(5):926-9. doi: 10.3171/JNS/2008/108/5/0926.
• Greif R, Akca O, Horn EP, Kurz A, Sessler DI; Outcomes Research Group. Supplemental perioperative oxygen to reduce the incidence of surgical-wound infection. N Engl J Med. 2000 Jan 20;342(3):161-7. doi: 10.1056/NEJM200001203420303.
• Xu F, Liu P, Pascual JM, Xiao G, Lu H. Effect of hypoxia and hyperoxia on cerebral blood flow, blood oxygenation, and oxidative metabolism. J Cereb Blood Flow Metab. 2012 Oct;32(10):1909-18. doi: 10.1038/jcbfm.2012.93. Epub 2012 Jun 27.
• Santarius T, Kirkpatrick PJ, Ganesan D, Chia HL, Jalloh I, Smielewski P, Richards HK, Marcus H, Parker RA, Price SJ, Kirollos RW, Pickard JD, Hutchinson PJ. Use of drains versus no drains after burr-hole evacuation of chronic subdural haematoma: a randomised controlled trial. Lancet. 2009 Sep 26;374(9695):1067-73. doi: 10.1016/S0140-6736(09)61115-6.
• Dexter F, Reasoner DK. Theoretical assessment of normobaric oxygen therapy to treat pneumocephalus. Anesthesiology. 1996 Feb;84(2):442-7. doi: 10.1097/00000542-199602000-00024.
• Miranda LB, Braxton E, Hobbs J, Quigley MR. Chronic subdural hematoma in the elderly: not a benign disease. J Neurosurg. 2011 Jan;114(1):72-6. doi: 10.3171/2010.8.JNS10298. Epub 2010 Sep 24.
• Chan DYC, Poon WS, Chan DTM, Mak WK, Wong GKC. Chronic subdural haematoma during the COVID-19 lockdown period: late presentation with a longer interval from the initial head injury to the final presentation and diagnosis. Chin Neurosurg J. 2021 Jan 8;7(1):4. doi: 10.1186/s41016-020-00229-7.
• Chan DY, Woo PY, Mak CH, Chu AC, Li CC, Ko NM, Ng SC, Sun TF, Poon WS. Use of subdural drain for chronic subdural haematoma? A 4-year multi-centre observational study of 302 cases. J Clin Neurosci. 2017 Feb;36:27-30. doi: 10.1016/j.jocn.2016.10.039. Epub 2016 Nov 30.
• Chan DY, Chan DT, Sun TF, Ng SC, Wong GK, Poon WS. The use of atorvastatin for chronic subdural haematoma: a retrospective cohort comparison study. Br J Neurosurg. 2017 Feb;31(1):72-77. doi: 10.1080/02688697.2016.1208806. Epub 2016 Nov 23.
• Chan DYC, Sun TFD, Poon WS. Steroid for chronic subdural hematoma? A prospective phase IIB pilot randomized controlled trial on the use of dexamethasone with surgical drainage for the reduction of recurrence with reoperation. Chinese Neurosurgical Journal. 2015; 1(1):2.

Study record dates

Study Major Dates

• Study Start (Actual): July 26, 2022
• Primary Completion (Anticipated): December 31, 2023
• Study Completion (Anticipated): December 31, 2024

Study Registration Dates

• First Submitted: January 19, 2021
• First Submitted That Met QC Criteria: January 21, 2021
• First Posted (Actual): January 27, 2021

Study Record Updates

• Last Update Posted (Actual): July 28, 2022
• Last Update Submitted That Met QC Criteria: July 26, 2022
• Last Verified: July 1, 2022

More Information

Terms related to this study

• Keywords: Recurrence; Oxygen therapy; Chronic subdural hematoma; Normobaric Oxygen; High concentration Oxygen; Pneumocephalus
• Additional Relevant MeSH Terms: Pathologic Processes; Cardiovascular Diseases; Vascular Diseases; Cerebrovascular Disorders; Brain Diseases; Central Nervous System Diseases; Nervous System Diseases; Wounds and Injuries; Disease Attributes; Hemorrhage; Craniocerebral Trauma; Trauma, Nervous System; Intracranial Hemorrhages; Brain Injuries; Intracranial Hemorrhage, Traumatic; Recurrence; Hematoma; Pneumocephalus; Hematoma, Subdural; Hematoma, Subdural, Chronic
• Other Study ID Numbers: NTEC-2021-0021

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: No

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No