Keywords
Endotracheal suctioning - intracranial pressure - midazolam - severe traumatic brain injury
INTRODUCTION
Maintenance of normal intracranial pressure (ICP) remains the cornerstone of management in severe traumatic brain injury (TBI) patients.[1] However, various procedures such as positioning, assessment of Glasgow coma scale (GCS) and endotracheal (ET) suctioning may be accompanied by deleterious variation in mean arterial pressure (MAP), ICP and cerebral perfusion pressure (CPP).
Adequate analgesia, sedation and muscle paralysis (using barbiturates) are usually used to prevent such undesirable increases in ICP during various procedures.[2] This has also led to a search of agents with shorter duration of action and fewer side effects than barbiturates.[3] Midazolam is a water-soluble, short-acting benzodiazepine that has been recommended as an effective IV agent for maintaining sedation as well as for induction of anaesthesia.[4]
The current study was designed to assess the effectiveness of midazolam in decreasing the rise of ICP during ET suctioning among severe TBI patients.
The secondary objectives of the study were:
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To determine the variation in ICP after administering bolus dose of Midazolam
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To compare the variation in ICP during ET suctioning both in the experimental and control group
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To determine the mean duration of time taken to return to baseline ICP after ET suctioning.
METHODS
A prospective, pilot study was conducted over 1 month (January 2014) using experimental research design after obtaining permission from the Ethics Committee of the Institute. Informed consent was obtained from the family members of patients. The null hypothesis was that the mean increase in ICP in experimental group will not be significantly lower than control group during ET suctioning.
Setting
Jai Prakash Narayan Apex Trauma Center of All India Institute of Medical Sciences is a level 1 trauma centre in Delhi, India. This study was conducted in the neurotrauma Intensive Care Unit in severe TBI (GCS ≤8) adult (age 18–60 years) male patients who were on mechanical ventillator and undergoing ICP monitoring. As per our protocol, all patients are treated with midazolam (0.2 mg/kg/h) and fentanyl (0.002 mg/kg/h) infusions for sedation.
Sample
Samples were collected using simple random sampling technique and patients were randomly assigned to the intervention and control group. ICP was monitored 2 min before, during and 2 min after ET suctioning in both interventional and control group and readings were noted. Bolus of 2 mg midazolam was given in the interventional group, 1 min before performing ET suction.
Statistical analysis
Statistical analysis was performed using SPSS IBM version 19 (IBM Corp. Released 2010. IBM SPSS Statistics for Windows, Version 19.0. Armonk, NY: IBM Corp.).
RESULTS
A total of twenty male patients were enrolled in the study who were randomly assigned to control and experimental group. There were 10 patients in the midazolam group and 10 patients in control group. A total of 80 readings were obtained from both the groups. As shown in [Table 1], both groups were well matched in age, admission GCS, MAP and baseline ICP.
Table 1
Baseline Characteristics of the study subjects
|
Variables
|
Mean±SD
|
P value
|
|
Intervention group (n=10)
|
Control group (n =10)
|
|
|
ICP = Intracranial pressure, GCS = Glasgow coma scale
|
|
Age
|
40.20±12.02
|
39.27±12.03
|
0.83
|
|
Admission GCS
|
7.73±02.25
|
08.27±02.63
|
0.556
|
|
Mean Arterial pressure
|
74.8±05.24
|
75.6±06.63
|
0.7681
|
|
Baseline ICP
|
16±2.32
|
15±1.89
|
0.360
|
The mean rise in ICP following ET suctioning in control group was found to be 24.1 mmHg (standard deviation [SD] - 11.1) and was 18.25 mmHg (SD - 9.29) in the midazolam group (P < 0.05).
The mean variation of ICP from the baseline value in midazolam group during ET suctioning was found to be 20.8 mmHg (SD - 0.48) and 28.4 mmHg with SD 0.68 in control group (P < 0.05).
The time taken for return of ICP to baseline was 15 min in control group and 10 min in midazolam group (P < 0.05).
DISCUSSION
In managing patients with severe TBI, it is essential to use techniques and pharmacological agents which do not modify ICP and CPP unfavourably.[3] Sedation is very effective in managing intracranial hypertension and is considered as one of the initial treatment steps, provided that the drugs chosen do not interfere with the cerebral haemodynamics.[5] Several studies advocate neuromuscular blockade to avoid ICP increases after ET suctioning.[6]
[7]
[8] However, we reserve neuromuscular blockade for intractable intracranial hypertension. Tateishi et al. have shown that diazepam causes a decrease in MAP and CPP.[9] Following diazepam administration, ICP was maintained when baseline values of ICP were >15 mmHg, but when baseline values were <15 mmHg, ICP decreased. However, this study was conducted in neurosurgical non-injured patients. Midazolam may offer some advantages compared with other benzodiazepines as it is a short-acting, water-soluble agent associated with cardiovascular stability.[10]
[12]
[15] Since midazolam is used as first-line sedative agent in TBI patients and is preferred over propofol in patients with haemodynamic instability, we had selected midazolam as an intervention and studied its effectiveness in decreasing the rise of ICP during ET suctioning.[11]
[13]
[14]
[16]
[17]
[18]
[19]
[20]
[21]
Our study shows that ET suctioning leads to significant rise in ICP despite ongoing sedation and 2 mg bolus of midazolam before suctioning may significantly reduce the rise in ICP. However, significant rise in ICP from baseline may still occur and additional interventions will need to be defined to stabilise ICP during suctioning in these patients.
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
