Effect of short-duration hyperventilation during endotracheal suctioning on intracranial pressure in severe head-injured adults

Effects of Routine Position Changes and Tracheal Suctioning on Intracranial Pressure in Traumatic Brain Injury Patients

Patient position change and tracheal suctioning are routine interventions in mechanically ventilated traumatic brain injury (TBI) patients. We sought to better understand the impact of these interventions on intracranial pressure (ICP) and cerebral hemodynamics. We conducted a prospective study in TBI patients requiring ICP monitoring. The timing of position changes and suctioning episodes were recorded with concurrent blood pressure and ICP measurements. We collected data on 460 patient position changes and 204 suctioning episodes over 2404 h in 18 ventilated patients (mean age 34 [13] years, median Glasgow Coma Score 4 [3-7]). We recorded 24 (20-31) positioning and 11 (6-18) suctioning episodes per patient, with 54% and 39% of position changes associated with ICP ≥22 mm Hg and cerebral perfusion pressure (CPP) <60 mm Hg, respectively, and 22% and 27% of suctioning episodes associated with an ICP ≥22 mm Hg and CPP <60 mm Hg. The median change in ICP was 11 (6-16) mm Hg after position changes and 3 (1-9) mm Hg after suctioning. Reduction in CPP to <60 mm Hg lasted ≥10 min in 17% of positioning and 11% of suctioning episodes. The baseline ICP and its amplitude were both predictive of a rise in ICP ≥22 mm Hg after positioning and suctioning episodes, whereas cerebral autoregulation was not. Baseline CPP was predictive of a decrease in CPP <60 mm Hg after both interventions. Increases in ICP and reductions in CPP are common following patient positioning and tracheal suctioning episodes. Frequently, these changes are substantial and sustained.

Rapid Sequence Intubation in Traumatic Brain-injured Adults

Deciding on proper medication administration for the traumatic brain injury (TBI) patient undergoing intubation can be daunting and confusing. Pretreatment with lidocaine and/or vecuronium is no longer recommended; however, high-dose fentanyl can be utilized to help blunt the sympathetic stimulation of intubation. Induction with etomidate is recommended; however, ketamine can be considered in the proper patient population, such as those with hypotension. Paralysis can be performed with either succinylcholine or rocuronium, with the caveat that rocuronium can lead to delays in proper neurological examinations due to prolonged paralysis. Recommendations for post-intubation continuous sedation medications include a combination propofol and fentanyl in the normotensive/hypertensive patient population. A combination midazolam and fentanyl or ketamine alone can be considered in the hypotensive patient.

Effects of lidocaine and magnesium sulfate in attenuating hemodynamic response to tracheal intubation: single-center, prospective, double-blind, randomized study

BACKGROUND AND OBJECTIVES

Hemodynamic response to airway stimuli is a common phenomenon and its management is important to reduce the systemic repercussions. The objective of this study is to compare the efficacy of intravenous magnesium sulfate versus lidocaine on this reflex hemodynamics after laryngoscopy and tracheal intubation.

METHODS

This single-center, prospective, double-blind, randomized study evaluated 56 patients ASA 1 or 2, aged 18-65 years, scheduled for elective surgeries under general anesthesia with intubation. The patients were allocated into two groups: Group F received 30mg·kg^-1 of magnesium sulphate and Group L, 2mg·kg^-1 of lidocaine, continuous infusion, immediately before the anesthetic induction. Blood pressure (BP), heart rate (HR), and bispectral index (BIS) were measured in both groups at six different times related to administration of the study drugs.

RESULTS

In both groups there was an increase in HR and BP after laryngoscopy and intubation, compared to baseline. Group M showed statistically significant increase in the values of systolic and diastolic blood pressure after intubation, which was clinically unimportant. There was no difference in the BIS values between groups. Among patients receiving magnesium sulfate, three (12%) had high blood pressure versus only one among those receiving lidocaine (4%), with no statistical difference.

CONCLUSION

Magnesium sulfate and lidocaine have good efficacy and safety for hemodynamic management in laryngoscopy and intubation.

[Effects of lidocaine and magnesium sulfate in attenuating hemodynamic response to tracheal intubation: single-center, prospective, double-blind, randomized study]

BACKGROUND AND OBJECTIVES

Hemodynamic response to airway stimuli is a common phenomenon and its management is important to reduce the systemic repercussions. The objective of this study is to compare the efficacy of intravenous magnesium sulfate versus lidocaine on this reflex hemodynamics after laryngoscopy and tracheal intubation.

METHODS

This single-center, prospective, double-blind, randomized study evaluated 56 patients ASA 1 or 2, aged 18 to 65 years, scheduled for elective surgeries under general anesthesia with intubation. The patients were allocated into two groups: Group F received 30mg·kg^-1 of magnesium sulphate and Group L, 2mg·kg^-1 of lidocaine, continuous infusion, immediately before the anesthetic induction. Blood pressure (BP), heart rate (HR), and bispectral index (BIS) were measured in both groups at six different times related to administration of the study drugs.

RESULTS

In both groups there was an increase in HR and BP after laryngoscopy and intubation, compared to baseline. Group M showed statistically significant increase in the values of systolic and diastolic blood pressure after intubation, which was clinically unimportant. There was no difference in the BIS values between groups. Among patients receiving magnesium sulfate, three (12%) had high blood pressure versus only one among those receiving lidocaine (4%), with no statistical difference.

CONCLUSION

Magnesium sulfate and lidocaine have good efficacy and safety for hemodynamic management in laryngoscopy and intubation.

Chest Physiotherapy in the Pediatric Intensive Care Unit

Despite widespread practice, there is very little, high-level evidence supporting the indications for and effectiveness of cardiopulmonary/chest physiotherapy (CPT) in critically ill infants and children. Conversely, most studies highlight the detrimental effects or lack of effect of different manual modalities. Conventional CPT should not be a routine intervention in the pediatric intensive care unit, but can be considered when obstructive secretions are present which impact on lung mechanics and/or gaseous exchange and/or where there is the potential for long-term complications. Techniques such as positioning, early mobilization, and rehabilitation have been shown to be beneficial in adult intensive care patients; however, little attention has been paid to this important area of practice in pediatric intensive care units. This article presents a narrative review of chest physiotherapy in pediatric critical illness, including effects, indications, precautions, and specific treatment modalities and techniques.

Racemic ketamine in adult head injury patients: use in endotracheal suctioning

INTRODUCTION

Endotracheal suctioning (ETS) is essential for patient care in an ICU but may represent a cause of cerebral secondary injury. Ketamine has been historically contraindicated for its use in head injury patients, since an increase of intracranial pressure (ICP) was reported; nevertheless, its use was recently suggested in neurosurgical patients. In this prospective observational study we investigated the effect of ETS on ICP, cerebral perfusion pressure (CPP), jugular oxygen saturation (SjO2) and cerebral blood flow velocity (mVMCA) before and after the administration of ketamine.

METHODS

In the control phase, ETS was performed on patients sedated with propofol and remifentanil in continuous infusion. If a cough was present, patients were assigned to the intervention phase, and 100 γ/kg/min of racemic ketamine for 10 minutes was added before ETS.

RESULTS

In the control group ETS stimulated the cough reflex, with a median cough score of 2 (interquartile range (IQR) 1 to 2). Furthermore, it caused an increase in mean arterial pressure (MAP) (from 89.0 ± 11.6 to 96.4 ± 13.1 mmHg; P <0.001), ICP (from 11.0 ± 6.7 to 18.5 ± 8.9 mmHg; P <0.001), SjO2 (from 82.3 ± 7.5 to 89.1 ± 5.4; P = 0.01) and mVMCA (from 76.8 ± 20.4 to 90.2 ± 30.2 cm/sec; P = 0.04). CPP did not vary with ETS. In the intervention group, no significant variation of MAP, CPP, mVMCA, and SjO2 were observed in any step; after ETS, ICP increased if compared with baseline (15.1 ± 9.4 vs. 11.0 ± 6.4 mmHg; P <0.05). Cough score was significantly reduced in comparison with controls (P <0.0001).

CONCLUSIONS

Ketamine did not induce any significant variation in cerebral and systemic parameters. After ETS, it maintained cerebral hemodynamics without changes in CPP, mVMCA and SjO2, and prevented cough reflex. Nevertheless, ketamine was not completely effective when used to control ICP increase after administration of 100 γ/kg/min for 10 minutes.

The effect of oral care on intracranial pressure: a review of the literature

Neuroscience intensive care unit nurses routinely perform oral care on patients with intracranial pressure (ICP) monitoring. When the ICP is elevated or rises in response to oral care, this intervention may be withheld despite the lack of evidence linking the two. To appraise the best evidence for providing oral care to patients with ICP monitoring, articles published in English from 1978 to 2009 and indexed in CINHAL, PubMed/MEDLINE, Cochran Library, and BioSys were searched using the key terms ICP monitoring, intracranial hypertension, oral care, mouth care, hygiene, nursing interventions, nursing care, intensive care, and critical care. Reference lists of retrieved articles were reviewed for articles missed during the initial search. The search yielded 65 articles: 16 experimental or quasi-experimental studies, 24 descriptive studies, and 25 review articles. Of these, only four specifically tested or described the effect of oral care on ICP. There is a need for more knowledge about the effect of oral care on ICP so that evidence-based oral care practices in this patient population can be defined.

The effect of nursing interventions on the intracranial pressure in paediatric traumatic brain injury

AIMS AND OBJECTIVES

The aim of this research was to investigate the effect of five selected intensive care nursing interventions on the intracranial pressure (ICP) of moderate to severe traumatic brain-injured children in intensive care.

BACKGROUND

The physiological effects of many nursing interventions in paediatric intensive care (PIC) are not known. This results in the lack of an evidence base for many PIC nursing practices.

DESIGN

Prospective observational cohort study conducted over 3 years in a single tertiary referral paediatric intensive care unit (PICU) in the North West of England.

METHODS

Five selected commonly performed nursing interventions were studied: endotracheal suctioning and manual ventilation (ETSMV), turning via a log-rolling (LR) approach, eye care, oral care and washing. These were studied in the first 72 h after injury.

RESULTS

A total of 25 children with moderate to severe traumatic brain injury and intraparenchymal ICP monitoring in intensive care (aged 2-17 years) were enrolled. Both ETSMV and LR were associated with clinically and statistically significant changes in ICP from baseline to maximal ICP (p = 0·001 ETSMV; p = < 0·001 LR) and from maximal post-ICP (p = < 0·001 ETSMV; p = < 0.001 LR). Eye care, oral care or washing did not cause any clinically significant change in ICP from baseline. After decompressive craniectomy, none of the interventions caused significant changes in ICP.

CONCLUSIONS

Only two of the five nursing interventions, endotracheal suctioning and LR, caused intracranial hypertension in moderate to severe traumatic brain-injured children, and after craniectomy, no care interventions caused any significant change in ICP.

RELEVANCE TO CLINICAL PRACTICE

Knowledge about the physiological effects of many intensive care nursing interventions is lacking and this is magnified in paediatrics. This study provides a significant addition to the evidence base in this area and allows intensive care nurses to plan, implement and evaluate more effectively their nursing care for brain-injured children.

The effect of breath physiotherapeutic maneuvers on cerebral hemodynamics: a clinical trial

OBJECTIVE

To observe the repercussion of respiratory physiotherapy techniques on the mean arterial pressure (MBP), intracranial pressure (ICP), cerebral perfusion pressure (CPP), jugular venous oxygen pressure (PjvO2) and jugular venous oxygen saturation (SjvO2).

METHOD

The sample consisted of 20 patients with head trauma. The protocol consisted of physiotherapy techniques application of vibrocompression (VBC), expiratory flow increase (EFI) and suction.

RESULTS

The results show the maintenance on variables of cerebral hemodynamics during the techniques of VBC and EFI. However, in relation to suction, there was an increase of MBP, ICP, with maintenance of CPP, PjvO2 and SjvO2 and return to baseline of MBP and ICP 10 minutes after the end of suction.

CONCLUSION

The respiratory physiotherapy techniques (VBC, EFI) do not promote cerebral hemodynamic repercussion, unlike suction, in severe head injury patients, mechanically ventilated, sedated and paralyzed.

Judgments of critical care nurses about risk for secondary brain injury

BACKGROUND

Interdisciplinary care for patients with traumatic brain injury focuses on treating the primary brain injury and limiting further brain damage from secondary injury. Intensive care unit nurses have an integral role in preventing secondary brain injury; however, little is known about factors that influence nurses' judgments about risk for secondary brain injury.

OBJECTIVE

To investigate which physiological and situational variables influence judgments of intensive care unit nurses about patients' risk for secondary brain injury, management solely with nursing interventions, and management by consulting another member of the health care team.

METHODS

A multiple segment factorial survey design was used. Vignettes reflecting the complexity of real-life scenarios were randomly generated by using different values of each independent variable. Surveys containing the vignettes were sent to nurses at 2 level I trauma centers. Multiple regression was used to determine which variables influenced judgments about secondary brain injury.

RESULTS

Judgments about risk for secondary brain injury were influenced by a patient's oxygen saturation, intracranial pressure, cerebral perfusion pressure, mechanism of injury, and primary diagnosis, as well as by nursing shift. Judgments about interventions were influenced by a patient's oxygen saturation, intracranial pressure, and cerebral perfusion pressure and by nursing shift. The initial judgments made by nurses were the most significant variable predictive of follow-up judgments.

CONCLUSIONS

Nurses need standardized, evidence-based content for management of secondary brain injury in critically ill patients with traumatic brain injury.

Intracranial Pressure Waveform Analysis During Rest and Suctioning

Cerebral compliance is a measure of cerebral adaptability to increases in volume within the intracranial space and an indicator of risk for neurological deterioration. However, no direct measurement of compliance exists in clinical practice to guide nursing care or treatment decisions. Current use of mean intracranial pressure (MICP) and gross morphological intracranial pressure waveform (ICPW) analysis have great variability in predicting outcomes. The purpose of this review and pilot study was to evaluate the effects of suctioning on MICP and other measures estimating cerebral compliance derived from analysis of ICPW on patient outcome. We analyzed arterial blood pressure waveforms (ABPWs), ICPWs, and respiratory cycle variations using Fourier Transform analysis, to explore the potential benefits of studying ICPWs across single cardiac and respiratory cycles using linear modeling and calculation of correlation coefficients. ABPWs, ICPWs, and MICP were measured over individual cardiac cycles across multiple respiratory phases in five critically ill neurological patients. Both direct and derived ICP measures, including Fourier analysis of ABP and ICP and the cross-transform between ABP and ICP, were correlated with patient outcome. This more complex waveform analysis of individual ABPW and ICPW together, and derived measures during both single cardiac and respiratory cycles, may provide information relevant to cerebral compliance and patient outcomes. Pending confirmation with additional data sets, this technique may be a useful real-time clinical tool to provide a measure of compliance and risk of neurological deterioration for clinicians.

A comprehensive review of pediatric endotracheal suctioning: Effects, indications, and clinical practice

OBJECTIVE

To provide a comprehensive, evidence-based review of pediatric endotracheal suctioning: effects, indications, and clinical practice.

METHODS

PubMed, Cumulative Index of Nursing and Allied Health Literature, and PEDro (Physiotherapy Evidence Database) electronic databases were searched for English language articles, published between 1962 and June 2007. Owing to the paucity of objective pediatric data, all reports dealing with this topic were examined, including adult and neonatal studies.

RESULTS

One hundred eighteen references were included in the final review. Despite the widespread use of endotracheal suctioning, very little high-level evidence dealing with pediatric endotracheal suctioning exists. Studies of mechanically ventilated neonatal, pediatric, and adult patients have shown that suctioning causes a range of potentially serious complications. Current practice guidelines are not based on evidence from controlled clinical trials. There is no clear evidence that endotracheal suctioning improves respiratory mechanics, with most studies pointing to the detrimental effect it has on lung mechanics. Suctioning should be performed when obstructive secretions are present rather than routinely. There is no clear evidence for the superiority of closed- or open-system suctioning, nor is there clear evidence for appropriate vacuum pressures and suction catheter size. Sterility does not seem to be necessary when suctioning. Preoxygenation has short-term benefits, but the longer-term impact is unknown. Routine saline instillation before suctioning should not be performed. Recruitment maneuvers performed after suctioning have not been shown to be useful as standard practice.

CONCLUSIONS

Endotracheal suctioning is a procedure used regularly in the pediatric intensive care unit. Despite this, good evidence supporting its practice is limited. Further, controlled clinical studies are needed to develop evidence-based protocols for endotracheal suctioning of infants and children, and to examine the impact of different suctioning techniques on the duration of ventilatory support, incidence of nosocomial infection, and length of pediatric intensive care unit and hospital stay.

Respiratory care in spinal cord injury with associated traumatic brain injury: bridging the gap in critical care nursing interventions

Spinal cord injury (SCI) is a devastating and challenging condition. The events that lead to SCI, such as road traffic accidents, falls, sports and violence [Top. Spinal Cord Inj. Rehabil. 5 (1999) 83], are also the common aetiologies of traumatic brain injury (TBI). It's not surprising then, that 20-50% of those with cervical SCI have TBI [J. Trauma 46 (1999) 450]. The literature pertaining to the management of either injury in isolation is vast, but lacking where the two conditions are experienced together and require distinct adaptations to interventions. Consequently, a gap in the literature exists. This paper focuses on those patients with SCI of the cervical spine with associated head injury, and pay particular attention to respiratory difficulties, and presents interventions required to minimise and treat the effects of such pulmonary compromise.

Nursing care of the acute head injury: a review of the evidence

This article aims to review the current evidence in relation to acute head injury care. Head injuries are a frequent cause of death and disability in western society with the first 72 h being an important period for prevention of further brain damage. The underlying physiology behind head injury and intracranial pressure will be discussed. The monitoring of intracranial pressure and implications for practice will be addressed. The specialized nursing care and drug therapy management that is necessary for acute head injury patients will be highlighted. Recommendations for practice will be given.

Effect of hyperventilation on extracellular concentrations of glutamate, lactate, pyruvate, and local cerebral blood flow in patients with severe traumatic brain injury

OBJECTIVE

To determine the potential adverse effects of brief periods of hyperventilation commonly used for acute neurologic deterioration.

DESIGN

Prospective clinical trial.

SETTING

University medical school.

PATIENTS

Twenty patients with severe traumatic brain injury.

INTERVENTIONS

The effect of 30 mins of hyperventilation (mean PaCO2, 24.6 mm Hg) on the extracellular metabolites associated with ischemia, and on local cerebral blood flow was studied by using microdialysis and local cerebral blood flow techniques. Normal appearing brain adjacent to evacuated hemorrhagic contusions or underlying evacuated subdural hematomas was studied. Hyperventilation trials were done 24-36 hrs after injury and again at 3-4 days after injury. Dialysate concentrations of glutamate, lactate, and pyruvate were measured before and for 4 hrs after the hyperventilation trials.

MEASUREMENTS AND MAIN RESULTS

At 24-36 hrs, hyperventilation led to a >or=10% increase in the extracellular concentrations of glutamate in 14 of 20 patients, with concentrations in those 14 patients 13.7-395% above baseline; a >or=10% increase in lactate in 7 of 20 patients (11.6-211% above baseline); and a >or=10% increase in the lactate/pyruvate ratio in eight of 20 patients (10.8-227% above baseline). At 3-4 days after injury, ten of 13 patients had an increase in glutamate of >or=10%, while only three of 13 patients had an increase in extracellular lactate and two of 13 patients had an increase in the lactate/pyruvate ratio of this magnitude. The hyperventilation associated increases in extracellular glutamate and lactate concentrations were significant ( P<.05; one-sample Student's -test) at both time points after injury, as was the lactate/pyruvate ratio at 24-36 hrs. A >or=10% decline in local cerebral blood flow was observed with hyperventilation in five of 20 patients at 24-36 hrs (range, 10.2-18.7% below baseline), and in ten of 13 patients studied at 3-4 days (11.3-54% below baseline). There was no correlation with the presence or absence of local CO2 vasoresponsivity and increases in the extracellular metabolites at either the early or late time points.

CONCLUSIONS

In brain tissue adjacent to cerebral contusions or underlying subdural hematomas, even brief periods of hyperventilation can significantly increase extracellular concentrations of mediators of secondary brain injury. These hyperventilation-induced changes are much more common during the first 24-36 hrs after injury than at 3-4 days.

[Endotrachael aspiration protocol in patients with serious cranial trauma. study of neurophysiological variables]

Aspiration of tracheobronchial secretions can cause noxious effects on neurophysiological variables. Different studies that refer to aspiration of secretions in Serious Cranial Trauma use hyperinsuflation and hyperoxygenation to minimize its repercussion on Intracranial Pressure and thus try to not contribute to the secondary lesion. After reviewing these studies, a protocol of tracheobronchial secretion aspiration was performed in our ICU in patients with serious cranial trauma subjected to mechanical ventilation in order to assess the effect of the aspiration of secretions in the neurophysiological variables following homogeneous and standardized guidelines. Neurological, hemodynamic, oxygenation and ventilation variables were analyzed before, during and after aspiration of secretions. When the results were compared before and during this, we observed a decrease in the Intracranial Pressure with increase of Cerebral Perfusion Pressure (due to increase of Mean Blood Pressure), maintaining the levels of PaCO2 and jugular saturation of O2, with an increase in the airway pressures. After finishing the aspiration process, all the affected values recovered. It is concluded that the aspiration of tracheobronchial secretions in patients with Severe Cranial Trauma, after standardized hyperinsuflation and hyperoxygenation, does not alter the hydrodynamics or brain use of O2.

Intracranial effects of endotracheal suctioning in the acute phase of head injury

In patients with head injury, endotracheal suctioning (ETS) is a potentially dangerous procedure, because it can increase intracranial pressure (ICP). The purpose of this prospective nonrandomized study was to evaluate the impact of ETS on intracranial dynamics in the acute phase of head injury. Seventeen patients with severe head injury (Glasgow Coma Score < or = 8, range 4-8), sedated and mechanically ventilated, were studied during the first week after trauma. Single-pass ETS maneuver (with a 16-French catheter, negative pressure of 100 mm Hg, and duration of less than 30 seconds) was performed 60 seconds after the FiO2 was increased to 100%. After ETS, FiO2 was maintained at 100% for another 30 seconds. Before and after ETS, arterial blood gases and jugular oxygen saturation (S(j)O2), ICP, and mean arterial pressure (MAP) were measured and cerebral perfusion pressure (CPP) was calculated. A total of 131 ETS episodes, which consisted of repeated assessment of each patient, were analyzed. Six patients in 20 cases coughed and/or moved during ETS because of inadequate sedation. After ETS, ICP increased from 20 +/- 12 to 22 +/- 13 mm Hg in well-sedated patients and from 15 +/- 9 to 28 +/- 9 mm Hg in patients who coughed and/or moved (mean change, 2 +/- 6 versus 13 +/- 6 mm Hg, P <.0001). CPP and S(j)O2 increased in well-sedated patients (from 78 +/- 16 to 83 +/- 19 mm Hg, and from 71 +/- 10 to 73 +/- 13%, respectively) and decreased in patients who reacted to ETS (from 79 +/- 14 to 72 +/- 14 mm Hg and from 69 +/- 7 to 66 +/- 9%, respectively), and the differences were significant (mean change, CPP: 5 +/- 14 versus -7 +/- 15 mm Hg, P =.003; (S(j)O2) 2 +/- 5 vs. -3 +/- 5%, P <.0001). In well-sedated patients, endotracheal suctioning caused an increase in ICP, CPP, and S j O 2 without evidence of ischemia. In contrast, in patients who coughed or moved in response to suctioning, there was a slight and significant decrease in CPP and S(j)O2. In the case of patients with head injuries who coughed or moved during endotracheal suctioning, we strongly suggest deepening the level of sedation before completing the procedure to reduce the risk of adverse effects.

Hyperventilation therapy for acute traumatic brain injury

BACKGROUND

Because hyperventilation is often associated with a rapid fall in intracranial pressure, it has been assumed to be effective in the treatment of severe head injury. Hyperventilation reduces raised intracranial pressure by causing cerebral vasoconstriction and a reduction in cerebral blood flow. Whether reduced cerebral blood flow improves neurological outcome however, is unclear.

OBJECTIVES

To quantify the effect of hyperventilation on death and neurological disability following head injury.

SEARCH STRATEGY

The search strategy drew on that of the Injuries Group as a whole. The reference lists of all relevant articles identified were checked and the first author of reports was contacted to ask for assistance in identifying any further trials. Most recent search was done in September 1999.

SELECTION CRITERIA

All randomised trials of hyperventilation, in which study participants had a clinically defined acute traumatic head injury of any severity. There were no language restrictions.

DATA COLLECTION AND ANALYSIS

We collected data on the participants, the timing and duration of the intervention, duration of follow up, neurological disability and death. Relative risks (RR) and 95% confidence intervals were calculated for each trial on an intention to treat basis. Timing, degree and duration of hyperventilation were identified a-priori as potential sources of heterogeneity between trials.

MAIN RESULTS

One trial of 113 participants was identified. Hyperventilation alone, as well as in conjunction with the buffer THAM showed a beneficial effect on mortality at one year after injury, although the effect measure was imprecise (RR=0.73; 95% CI 0.36;1.49 and RR=0.89; 95% CI 0.47;1.72 respectively). This improvement in outcome was not supported by an improvement in neurological recovery. For hyperventilation alone, the RR for death or severe disability was 1. 14 (95% CI 0.82;1.58). The RR for death or severe disability in the hyperventilation plus THAM group, was 0.87 (95% CI 0.58;1.28).

REVIEWER'S CONCLUSIONS

The data available are inadequate to assess any potential benefit or harm that might result from hyperventilation in severe head injury. Randomised controlled trials to assess the effectiveness of hyperventilation therapy following severe head injury are needed.

Effect of endotracheal suctioning on cerebral oxygenation in traumatic brain-injured patients

OBJECTIVE

In patients with severe head injuries, brain damage occurs not only from the primary trauma but also secondarily from a reduction in cerebral oxygenation as a result of brain swelling, ischemia, and elevated intracranial pressure (ICP). However, routine interventions designed to maintain oxygenation, such as endotracheal suctioning (ETS), also may negatively affect the cerebrovascular status by increasing the ICP. The purpose of this study was to determine whether ETS influences cerebral oxygenation in patients with traumatic brain injury.

DESIGN

Descriptive, prospective, with repeated assessments within each patient.

SETTING

Ten-bed trauma intensive care unit in a university Level I trauma center.

SUBJECTS

Nineteen patients who were 16 yrs or older, had acute head injury, a Glasgow Coma Scale score < or =8; external ventricular drain and arterial pressure devices in place, and were intubated and mechanically ventilated.

INTERVENTIONS

ETS protocol consisting of administration of four ventilator-delivered breaths at 135% of the patients' actual tidal volume, 100% F(IO)2, before and after suctioning with a standardized catheter at a 16-L flow rate.

MEASUREMENTS AND MAIN RESULTS

This study examined cerebrovascular responses as measured by the traditional measures of ICP and cerebral perfusion pressure, as well as middle cerebral artery velocity and jugular venous oxygen tension that occurred during ETS in head-injured adults. The results of this study show that both ICP and cerebral perfusion pressure are increased during ETS. In the majority of patients (84%), the ICP returned to baseline values within 2 mins.

CONCLUSIONS

The increase in jugular venous oxygen tension associated with increases in middle cerebral artery velocity and mean arterial pressure suggests that cerebral oxygen delivery was maintained during ETS. Cerebral changes associated with ETS using the described protocol are consistent with the preservation of cerebral oxygenation.

Head injury: complications and management

Considerable effort and substantial funding has gone towards the development of a neuroprotective agent that could be given after brain trauma to reduce mortality and improve functional recovery. There have been many failed or inconclusive studies to date. In Europe two promising studies have been stopped or shelved (Lubeluzole, Janssen-Cilag and BAYx3702, Bayer) and the future of pharmacological neuroprotection after traumatic brain injury is in doubt. Clinicians managing patients with a head injury are therefore left with the detection and prevention of secondary insults to the brain, including the management of medical complications of brain injury, and non-pharmaceutical interventions that might beneficially modify the brain's response to trauma. Of the potential interventions, moderate hypothermia is the most promising.