TABLE 2.
Main representative studies evaluating link between NIRS, TDF-based CBF and CBFV with age/biological sex.
| References | Monitoring technique | Number of patients | Patient characteristics | Relevant results | Relevant conclusions |
|---|---|---|---|---|---|
| NIRS | |||||
| Adatia et al. (2020) | - NIRS INVOS 5100 | 104 | - Severe brain injury; - GCS ≤8 | Sex: 43 females in the group With Midline Shift and 6 females in the group Without Midline Shift | - Mean rSO2, median (IQR) in group With Midline shift was 64.7% (52–68.1%) and in group Without Midline Shift was 60.5% (45.1–65.2%), p = 0.39 for both groups |
| Two groups of females were studied: Mean and SD was 6±3 in the Patients With Midline Shift group and 7±3 in the Patients Without Midline Shift group (controls) | - Mean age: 59±15 years in the group With Midline Shift and 62±16 years in the group Without Midline Shift, p = 0.36 | - It was noted that patients without midline shift were older and had lower mean rSO2 | |||
| Adatia et al. (2018) | - NIRS INVOS 5100 | 85 (16 with TBI) | - Severe brain injury; - GCS ≤8 | - Sex: females in No Change group = 3, in Increasing group = 4, in Decreasing group = 6 and in Fluctuating group = 27, p = 0.40 | - Mean rSO2 with median IQR in No Change group was 66% (12%), Increasing group was 57% (16%), Decreasing group was 63% (8%) and Fluctuating group was 17% (21%), p = 0.13 for all groups |
| Data was for females in four different temperature groups: Median (IQR) GCS in No Change group was 3 (3), Increasing and Decreasing group was 7 (2) and Fluctuating group was 7 (4) | - Median and IQR age: in No Change group was 54 IQR 31 years, Increasing group was 59 IQR 23 years, Decreasing group was 61 IQR 21 years and Fluctuating group was 60 IQR 18 years, p = 0.38 | - Highest rSO2 was noted in the youngest patients belonging to the No Change group | |||
| CBF | |||||
| Dias et al. (2015) | - Parenchymal thermal diffusion probe | 18 | - Severe TBI | - Sex: 26 females; 16 males | - The 15 patients who were part of the Cerebrovascular Reactivity (CVR) Preserved PRx <0.25 group had mean CBF of 39.0±20.9 ml/100 g/min and the 3 patients who were part of the CVR Impaired PRx >0.25 group had mean CBF of 36.3±22.2 ml/100 g/min, p 0.953 for both groups |
| - Patients were divided into two groups | - Mean age: 42 SD 16 years | - Patients in the impaired group were noted to be older and had lower CBF | |||
| Median baseline GCS was 6 IQR 3, Median (IQR) in the Cerebrovascular Reactivity (CVR) Preserved PRx <0.25 group was 7 (4) and CVR Impaired PRx >0.25 group was 4 (2) | 15 patients with mean age of 40±16 years were part of the Cerebrovascular Reactivity (CVR) Preserved PRx <0.25 group and 3 patients with mean age of 52±11 years were part of the CVR Impaired PRx >0.25 group | ||||
| Dickman et al. (1991) | - Cortical thermal diffusion probe | 12 | - Moderate and severe TBI | - Sex: 8 males; 4 females | - The following are CBF patterns seen in this study: A 25 year old female maintained normal CBF, 3 males and 1 female age range 30–65 years had reduced CBFs, 3 died and one had a vegetative outcome |
| - Mean GCS at admission was 6 range 4–12 | - Mean age: 31 range 7–65 years | 4 males and 3 females age range 7–48 years had elevated CBFs, 5 died, 1 had mild cognitive deficits and 1 was in a persistent coma for 16 months after injury | |||
| CBFV | |||||
| Czosnyka et al. (2005) | - Doppler Ultrasound | - 358 patients total, 237 had CBFV monitoring | - Mild to severe brain injury | - Sex: 288 males; 60 females | - Blood flow velocity was not dependent on age (p = 0.58) |
| - GCS scores ranged from 3–15 | - Age range: 16–87 years | - No mention was made of a relationship with patient sex | |||
| Bouzat et al. (2011) | - Transcranial Doppler (TCD) | 98 | - Mild to moderate; - GCS 9–15 | - Sex: 64 males and 13 females in the group with No SND and 20 males and 1 female in the group with SND | - Mean blood flow velocity (FVm) was lower at 31 range 18–60 cm/s in the SND group as compared to the No SND group where FVm was higher at 49 range 31–80 cm/s, p < 0.01 for both groups |
| Two groups of patients were studied: Initial GCS score in group with No secondary neurological deterioration (SND) was 14 (9–15) and in the group with SND was 13 (10–15) | - Age and range: 34, 15–84 years in the group with No SND and 46 range 20–80 years in the group with SND, p = 0.04 | - Patients in the SND were older and had low FVm | |||
| Cardim et al. (2020) | - Transcranial Color-Coded Duplex (TCCD) | 95 | - Severe TBI | - Sex: 70 males; 25 females | - No significant correlation was found between CBFV and age |
| - GCS ranged from 3–8 | - Age: Patients were older than 18 years and divided into 3 age groups: group 1 was young adults 18–44 years, group 2 was middle-aged adults 45–64 years and group 3 was older adults above 65 years | - Total FVm and median IQR in males across all age groups was 65.67 (58.41–71.67 cm/s) and for females was 71.67 (62.67–78.67 cm/s), p ≤ 0.05 for both groups | |||
| - There was a significant variation in FVm between males and females with females FVm higher in each age group compared to males | |||||
| - Also, FVm in the older group 3 patients were lowest in both males and females | |||||
| Hu et al. (2008) | - TCD | 30 | - Moderate to severe | - Sex: Data provided for two groups of patients: in Brain Injury group – 23 males and 7 females and in the Control group – 8 males and 4 females | - In Brain Injury group mean CBFV on the left was 65.7±33.9 cm/s and in Control group was 56.5±19.8 cm/s |
| - Mean GCS was 6 range 3–13 | - Mean age: in Brain Injury group was 38±16 years and in the Control group was 43.7±11.9 years | - In Brain Injury group mean CBFV on the right was 62.5±28.2 cm/s and in Control group was 57.4±16.1 cm/s | |||
| - CBFV was higher in the patients than in controls and patients were younger than controls | |||||
% = percentage, CBF(s) = cerebral blood flow(s), cm/s = centimeters per second, CVR, cerebrovascular reactivity; FVm, mean blood flow velocity, GCS, glasgow coma scale; IQR, interquartile range, ml/100 g/min = milliliters per 100 g per minute, NIRS, near infrared spectroscopy, p = p-value, PRx, pressure reactivity index, rSO2 = regional cerebral oxygen saturations, SD, standard deviation; SND, secondary neurological deterioration; TBI, traumatic brain injury; TCD, transcranial Doppler; TCCD, Transcranial Color-Coded Duplex.