Journal of Neuroscience Nursing:
Monitoring and Sedation Differences in the Management of Severe Head Injury and Subarachnoid Hemorrhage Among Neurocritical Care Centers
Skoglund, Karin; Enblad, Per; Marklund, Niklas
Questions or comments about this article may be directed to Karin Skoglund, RN ICN PhD, at email@example.com. She is an Assistant Professor at the School of Health, Care and Social Welfare, Mälardalen University, Eskilstuna, Sweden.
Per Enblad, PhD, is a Professor at the Department of Neuroscience, Neurosurgery, Uppsala University Hospital, Uppsala University, Uppsala, Sweden.
Niklas Marklund, PhD, is an Associate Professor at the Department of Neuroscience, Neurosurgery, Uppsala University Hospital, Uppsala University, Uppsala, Sweden.
The authors declare no conflicts of interest.
Background: The emergence of specialized neurocritical care (NCC) centers has been associated with an improved survival of patients with severe traumatic brain injury or subarachnoid hemorrhage. However, there are no established guidelines on sedation strategy or the frequency of evaluating the level of consciousness using the neurological wake-up test (NWT) in sedated NCC patients.
Objectives: The aim was to compare the (1) monitoring techniques, (2) sedation principles, and (3) the use of the NWT in patients with severe traumatic brain injury or subarachnoid hemorrhage in 16 NCC centers.
Method: A systematic survey of all 16 centers providing NCC in Scandinavia was performed using a questionnaire regarding the routine primary choice of sedative and analgesic compounds, monitoring techniques, and the frequency of the NWT, sent to the director of each center during 1999, 2004, and 2009.
Results: The response rate was 100%. Except for one center in 1999, all included centers routinely used monitoring of intracranial and cerebral perfusion pressure. In contrast, newer monitoring techniques such as microdialysis, jugular bulb oximetry, and brain tissue oxygenation were infrequently used throughout the survey period. Approximately half of the NCC centers used propofol infusion as the primary sedative, whereas the remaining centers used midazolam infusion, and there was a marked variation in the choice of analgesia in each evaluated year. The NWT was never used in 50% of centers and ≥six times daily in one center from 1999 to 2009. Most differences among the NCC centers remained unchanged over the evaluated 10-year period.
Discussion: Although Scandinavian countries have similar healthcare systems, there were marked differences among the participating NCC centers in the choice of monitoring tools and sedatives and the routine use of the NWT. These differences likely reflect different clinical management traditions and a lack of evidence-based guidelines in routine NCC.
Traumatic brain injury (TBI) is a major global health problem, affecting predominately young people, and its incidence shows a sharp increase globally (Maas, Stocchetti, & Bullock, 2008). In the Western World, TBI is a leading cause for premature death and disability with a huge socioeconomic impact (Maas et al., 2008). The incidence rate for TBI in Europe is estimated to 150–300 per 100,000 of population per year (Tagliaferri, Compagnone, Korsic, Servadei, & Kraus, 2006) and 246–272 per 100,000 in Sweden (Kleiven, Peloso, & von Holst, 2003). In addition, subarachnoid hemorrhage (SAH) is a common and often devastating disease with an approximate incidence of 9 of 100,000, highly dependent on geographic region, gender, and age (de Rooij, Linn, van der Plas, Algra, & Rinkel, 2007). To date, the mortality of SAH is 25%–50%, and significant morbidity is observed in approximately 50% of those who survived (Suarez, Tarr, & Selman, 2006). Despite considerable and continuing advances in prehospital and in-hospital management, the outcome for patients with both TBI and SAH remains poor. Furthermore, with the exception of nimodipine for SAH patients, no pharmaceutical treatment options for TBI or SAH exists (Ferro, Canhao, & Peralta, 2008; Maas et al., 2008; Marklund, Bakshi, Castelbuono, Conte, & McIntosh, 2006).
Thus, improved treatment for patients with TBI and SAH is urgently needed. The emergence of specialized NCC centers was developed during the 1980s (Rincon & Mayer, 2007), and their focus on the diagnosis, treatment, and monitoring of the injured brain has been associated with an improved outcome in both patients with TBI and SAH (Elf, Nilsson, & Enblad, 2002; Patel et al., 2002; Ryttlefors, Howells, Nilsson, Ronne-Engstrom, & Endblad, 2007). One basic hypothesis of NCC is that secondary insults occurring during the first hours to days after the primary brain injury impair patient outcome and that the improved monitoring allows for the detection and treatment of these secondary “avoidable” factors (Elf et al., 2002; Maas et al., 2008; Patel et al., 2002; Ryttlefors et al., 2007). The principles of NCC have, in many centers, developed into a protocol system containing written standardized operative procedures for both basic nursing and medical treatment (Arabi et al., 2009; Fakhry, Trask, Waller, & Watts, 2004; Patel et al., 2005). Although there are numerous existing controversies with regards to NCC practice, general agreement and available guidelines suggest that monitoring of intracranial pressure (ICP) and cerebral perfusion pressure (CPP) should be available for unconscious patients with TBI (Andrews et al., 2008; Bratton et al., 2007b). ICP and CPP monitoring should also be used in patients with poor-grade SAH (Bederson et al., 2009).
During the past decades, several additional brain monitoring technologies have been developed, including microdialysis (MD), brain tissue oxygen monitoring (PbtiO2), and jugular venous oxygen saturation (SjvO2; Maas et al., 2008). Although these techniques have received much interest, there is only limited available evidence arguing that their use results in an improved outcome for brain-injured patients in NCC (Haitsma & Maas, 2007; Hillered, Persson, Nilsson, Ronne-Engstrom, & Enblad, 2006; Samuelsson, Hillered, Enblad, & Ronne-Engstrom, 2009; Stevens, 2004; Zetterling et al., 2010). Continuous electroencephalogram (cEEG) is routinely used for the monitoring of sedation depth in patients treated with sodium pentobarbital (Bratton et al., 2007d) and is also recommended in patients with poor-grade SAH (Claassen, Mayer, & Hirsch, 2005). Assessment of the level of consciousness (here named as the neurological wake-up tests [NWTs]; Skoglund, Enblad, & Marklund, 2009) according to the Glasgow Coma Scale (GCS; Teasdale & Jennett, 1974) and/or the Reaction Level Scale (RLS 85; Starmark, Stalhammar, & Holmgren, 1988) may be considered an additional intermittent monitoring tool in the NCC, performed by NCC nurses or physicians. The NWT procedure is performed in a standardized manner with the patient in supine position. Evaluation of any motor weakness, pupil size, and pupil reactivity to light is also included in the NWT. However, the NWT requires that the continuous sedation must be interrupted, which may induce a stress response (Skoglund, Enblad, Hillered, & Marklund, 2012; Skoglund et al., 2009), and this procedure is controversial in NCC practice (Helbok & Badjatia, 2009).
Sedation in general intensive care practice is used to, for example, limit the stress response and for endotracheal tube tolerance and ventilatory support. In the NCC setting, continuous sedation also facilitates ICP and CPP control and reduces cerebral energy metabolism (Beretta, De, & Grandi, 2011; Citerio & Cormio, 2003). Sedation in NCC patients may also be used as a specific therapy (Beretta et al., 2011). In the experimental TBI setting, the choice of anesthesia markedly influences outcome (Statler et al., 2006). In NCC, sedation practice is mainly based on local routines because of a lack of available guidelines. However, differences among NCC centers are largely unknown and have only infrequently been addressed in previous reports (Bulger et al., 2002; Jacka & Zygun, 2007; Johnston, King, Protheroe, & Childs, 2006; Stevens, Naval, Mirski, Citerio, & Andrews, 2009).
In Scandinavia, a geographic region spanning 817,000 km2 and with approximately 17 million inhabitants, NCC for patients with acute SAH or severe TBI is provided by 16 centers in university hospital settings (six in Sweden, five in Norway, and five in Denmark). In these countries, the healthcare system is similarly composed of public, state-owned hospitals. The aim of the present report was to compare the standard monitoring and sedation principles for patients with SAH and TBI in Scandinavian NCC centers and to evaluate the frequency of NWTs. In addition, all comparisons were repeated three times over a 10-year period (1999, 2004, and 2009).
Material and Methods
We systematically surveyed all 16 Scandinavian centers providing neurosurgical and NCC coverage, all being public hospitals in a university hospital setting. These university centers are either specialized NCC or general intensive care units (ICUs) experienced in brain injury management. The total number of beds for patients with acute TBI and SAH in these 16 centers is about 200 where approximately 40 beds are in general ICUs and 55 are in neurocritical care step-down units. The vast majority of patients with TBI or SAH treated in these centers are adults, >18 years old, and the management and monitoring of severely brain-injured patients with TBI or SAH was analyzed. A questionnaire was sent via mail together with a cover letter to the director of each NCC/ICU in 1999, 2004, and 2009.
Questionnaire and Data Analysis
The questionnaire was sent together with an addressed envelope to return the survey. From the responses to the questionnaire, we analyzed the number of centers using a certain treatment or monitoring techniques and noted any difference in routine management over time.
The questionnaire contained questions regarding the choice of anaesthetic and sedative agents, frequency of the NWT, and monitoring techniques (for details, see below) that are routinely used for patients with TBI or SAH. To enhance response rate, questions were limited, and the questionnaire contained straightforward questions that also gave the respondents the opportunity to explain in detail or expand on each answer (Appendix 1). The same questions were used in the questionnaires in 1999, 2004, and 2009. In the event of an unambiguous response, the written answer was clarified via a telephone interview. All center directors were also contacted via separate E-mails for information regarding their use of GCS and/or RLS as a neurological evaluation scale.
The answers from the questionnaire were placed in a data sheet for the analysis of monitoring techniques, choice of sedation, and frequency of NWT.
For all three questionnaires, a 100% response rate was achieved. The evaluated centers are either specialized NCC units (n = 12) or general ICUs (n = 4) experienced in brain injury management. In Sweden, five of six centers are designated NCC units under a neurosurgical/neurointensivist management, and the remaining center is in a general ICU setting. In Norway two of five centers are NCC centers, whereas the remaining three centers are general ICUs. In Denmark, five of five centers are NCC centers.
Routine Monitoring of Patients With TBI or SAH
From 2004 and onwards, all Scandinavian centers routinely and continuously monitor ICP, intraarterial MABP, and CPP. ICP was measured by external ventricular drainage and/or intraparenchymal technique (n = 12), external ventricular drainage only (n = 2), or intraparenchymal technique only (n = 2; Table 1).
CVP monitoring was used in all the NCC/ICUs since 1999 and onwards. In contrast, EtCO2 monitoring was frequently used in Sweden and increasingly in Denmark, although from 1999 to present, not in any Norwegian centers (Table 1).
In 2009, five NCC units/ICUs used MD. SjvO2 was rarely used in routine NCC of patients with TBI or SAH in the evaluated centers, summarized in Table 1.
PbtiO2 monitoring was not routinely used in any center in 1999 but increased to two Swedish and two Danish centers in 2009 (Table 1).
The use of cEEG monitoring increased from three Scandinavian centers in 1999 to five in 2004. However, only two Swedish centers routinely used this monitoring technique 5 years later in 2009 (Table 1).
Routine Sedation and Analgesia for Intubated and Ventilated Patients With TBI or SAH
In 1999 (Figure 1), 10 centers used midazolam infusion as their first choice of continuous sedation, either alone (n = 1) or combined with morphine (n = 3), fentanyl infusion (n = 5), or intermittent fentanyl injections (n = 1). Six centers in Sweden (n = 4) and Denmark (n = 2) used propofol infusion either alone (n = 1) or combined with morphine infusion (n = 2), infusion (n = 1), or intermittent fentanyl injections (n = 2).
Note. Propofol and midazolam were equally used in two centers in 2004 (indicated with*) and in one center in 2009 (indicated with**).
In 2004 (Figure 1), 11 centers used predominately midazolam infusion combined with either fentanyl (n = 7), morphine infusion (n = 2), fentanyl or remifentanil (n = 1), or morphine or alfentanil (n = 1). Seven centers used predominately propofol infusion for sedation combined with either intermittent injection (n = 2) or continuous (n = 1) infusion of morphine, and the four remaining centers combined propofol infusion with fentanyl (n = 1), sufentanil (n = 1), either fentanyl or remifentanil (n = 1), or a combination of midazolam and morphine (n = 1). Two Danish centers equally used propofol or Midazolam infusion.
In 2009 (Figure 1), nine centers predominately used midazolam infusions together with either fentanyl infusion (n = 7), morphine infusion (n = 1), or both fentanyl or morphine infusion (n = 1). Eight centers used predominately propofol infusion either alone (n = 2) or together with infusions of fentanyl (n = 3), morphine (n = 1), remifentanil (n = 1), or sufentanil (n = 1). One Danish NCC center equally used continuous infusion with propofol or Midazolam.
Overall, the changes in routine sedation were small during the evaluated 10-year period. Three centers (two Danish, one Norwegian) changed from midazolam infusion in 1999 to propofol sedation (n = 1) or to equally using propofol or midazolam infusion (n = 1) in 2009. In addition, one Swedish center changed from propofol sedation in 1999 to midazolam sedation in 2004 and 2009.
Frequency of NWTs
In five Swedish centers, the RLS was used, and in all remaining 11 Scandinavian centers, the GCS was used to evaluate the NWT. In occasional responses (n = 3), some centers responded that the NWT was performed “a few times during the total treatment period.” Because the purpose of this questionnaire was to evaluate the use of NWT as a daily monitoring tool, this response was registered as “never” (see below).
The frequency of the NWT, performed on a daily basis, varied considerably (Figure 2). In Sweden, the NWT was never performed (n = 3) or performed one to three times daily (n = 1), four to six times daily (n = 1), or >six times daily (n = 1; our center is in Uppsala, Sweden) in 1999. Between 1999 and 2004, one center reduced the frequency of NWT from four to six times daily to one to three times daily. Finally, in 2009 the NWT was never performed (n = 3) or performed one to three times daily (n = 2) or four to six times daily (n = 1).
Note. Approximately 50% of centers never interrupt the continuous sedation to enable the NWT.
In Norway, no center performed NWT on a daily basis in 1999. In both 2004 and 2009, one Norwegian center performed the NWTs one to three times daily. The Norwegian center using the NWT in 2004 was different from the center using this monitoring tool in 2009. In 1999 and 2004, three Danish centers performed the NWT one to three times daily and four centers in 2009.
In the present report, we evaluated the similarities and differences between NCC centers on certain aspects of routine NCC management of intubated and sedated patients with TBI or SAH. In addition, we evaluated if any changes in the management occurred over a 10-year period. The results of our report confirm our hypothesis that there are large variations in the choice of sedative and analgesic drugs used for patients with TBI and SAH and that the frequency of neurological assessment varies markedly among Scandinavian NCC centers. This heterogeneity likely reflects the lack of established guidelines in many aspect of NCC and the variability of established local routines.
It is well established that the primary, initial impact following both TBI and SAH is followed by a complex series of physiological and biochemical events, markedly exacerbating the initial injury. Neuroworsening and delayed ischemic deficits are well-known clinical problems in the care of patients with TBI and SAH (Maas et al., 2008; Rabinstein, Lanzino, & Wijdicks, 2010), and much effort is aimed at detecting and treating sign of ongoing brain damage during NCC. These secondary “avoidable” factors are associated with the clinical outcome following both TBI and SAH (Elf et al., 2002; Patel et al., 2002, 2005; Ryttlefors et al., 2007). Therefore, one main focus of modern NCC is to control and maintain intracranial dynamics via detailed monitoring of the injured brain.
In this study, we conclude that all evaluated centers currently use ICP and CPP monitoring in accordance with clinical guidelines for patients with TBI and SAH (Andrews et al., 2008; Bederson et al., 2009 Bratton et al., 2007a, 2007b). However, the use of other brain monitoring techniques such as PbtiO2, SjvO2, and MD varied considerably among units, countries, and over time. A consensus report from the neurointensive care and medicine section of the European Society of Intensive Care Medicine concluded that more prospective clinical data are needed to better evaluate these monitoring techniques (Andrews et al., 2008). Of these techniques, MD and PbtiO2 may be considered to monitor a focal brain region in contrast to a more global assessment of cerebral oxygenation using SjvO2 (Haitsma & Maas, 2007; Hillered, Vespa, & Hovda, 2005). Studies of PbtiO2 have observed a correlation between prolonged periods of low PbtiO2 values and poor outcome (Haitsma & Maas, 2007). In addition, brain hypoxia may occur despite normal ICP and CPP values, and in a previous clinical study, brain oxygenation monitoring was associated with an improved outcome (Stiefel et al., 2006). Guidelines from the Brain Trauma Foundation suggested that PbtiO2 and SjvO2 could be considered as an additional monitoring tool, combined with ICP monitoring, in the management of patients with severe TBI (Bratton et al., 2007c). Finally, electrographic and clinically silent seizures are common after acute brain injury (Claassen et al., 2005; Vespa et al., 1999), and one indication for cEEG monitoring is patients treated with high-dose sodium pentobarbital. However, our results suggest that the use of this monitoring modality is not increasing in Scandinavia; in contrast, less centers use cEEG in 2009 when compared with those in 1999. Lack of experience with the technique and uncertainty of the added clinical value may contribute to its limited use. Although several studies have concluded improved outcome in patients with TBI with the introduction of standard protocols during NCC (Arabi et al., 2009; Elf et al., 2002), these protocols instead focused on stepwise standard treatments and do not outline the use of monitoring other than ICP and CPP. Likely, the differences in neuromonitoring among centers observed in the present report reflect an uncertainty of the clinical value of many of these techniques. However, we argue that increased information of the injured brain may be beneficial and enhance the understanding of the pathophysiology of acute brain injury.
Sedation is required and used in patients with acute brain injury with a depressed level of consciousness for many reasons, including an attenuation of the stress response and increased sympathetic discharge, endotracheal tube tolerance, reduction of the cerebral energy metabolic demands, and management of ICP and CPP (Beretta et al., 2011; Citerio & Cormio, 2003). Thus, severely brain-injured patients with a depressed level of consciousness are frequently treated with mechanical ventilation and continuous sedation. Here, we observed that the evaluated NCC units equally chose either propofol or midazolam. These sedatives are widely used in NCC units (Beretta et al., 2011) but also in general ICUs (Samuelsson, Larsson, Lundberg, & Fridlund, 2003). Interestingly, very few clinical studies have compared the efficacy of these compounds in NCC, although one clinical TBI study compared the effects of midazolam and propofol on brain injury biomarker concentration in plasma and patient outcome and found no differences (Ghori et al., 2007). Recently, MD revealed no differences between propofol and midazolam on the cerebral energy metabolic profile after TBI (Tanguy et al., 2012).When evaluated in experimental TBI, propofol-anaesthetized animals had worse outcome compared with midazolam-anaesthetized animals (Statler et al., 2006). Because of numerous factors, the choice of sedatives may influence both short- and long-term outcomes. The rapid onset and short duration of action makes propofol advantageous when using frequent NWTs, and propofol may have superior cerebral metabolic suppressive effects and a shorter half-life compared with midazolam (Citerio & Cormio, 2003; Helmy, Vizcaychipi, & Gupta, 2007). However, disadvantages of propofol include high costs, cardiovascular collapse, metabolic acidosis, rhabdomyolysis, and bradycardia (Beretta et al., 2011; Fudickar & Bein, 2009). In addition, propofol is not approved for pediatric use in many countries, and the clinical efficacy of propofol sedation on outcome after TBI or SAH needs to be established (Adembri, Venturi, & Pellegrini-Giampietro, 2007). Midazolam may thus be a useful alternative to propofol (Walder, Elia, Henzi, Romand, & Tramer, 2001), although when administered as a continuous infusion for more than 24 hours, accumulation of active metabolites may pose a problem (Beretta et al., 2011), and escalated doses of midazolam have been reported (Shafer 1998).
In our department, continuous propofol sedation is used to facilitate frequent NWTs in the clinical management of patients with TBI and SAH despite mild NWT-induced elevation of ICP and CPP and certain stress hormones (Skoglund et al., 2009, 2012). The introduction of spontaneous awakening trials, similar to the NWT procedure, in general ICU was recently associated with a reduced ICU stay and better outcome and was suggested to become routine practice (Girard et al., 2008; Kress, Pohlman, O’Connor, & Hall, 2000; Ostermann, Keenan, Seiferling, & Sibbald, 2000; Wittbrodt, 2005). However, in a randomized control trial, a subgroup of patients with TBI did not show a decreased ventilator time or ICU stay when sedation was interrupted on a daily basis compared with controls (Anifantaki et al., 2009). Here, our results clearly indicate that the frequency of the NWT procedure varies markedly among centers. One reason may be that midazolam, used in approximately half of the evaluated centers, makes repeated NWTs more difficult. Likely, additional important reasons include a fear for inducing a NWT-induced stress response, lack of experience with the technique, and an uncertainty of its clinical use. In this survey, the frequency of NWTs did not differ between specialized NCC centers and general ICUs.
One important aim of this study was to illustrate variations in practice and management during NCC management of patients with TBI and SAH. We show that there are numerous differences among centers in countries with a very similar healthcare structure. Previously, other aspects of the management of patients with TBI and SAH have been evaluated where marked differences in numerous aspects of NCC both among centers but also among countries in North America (Ghajar et al., 1995; Jacka & Zygun, 2007; Kramer et al., 2011; Stevens et al., 2009) and Europe (De Kruijk, Twinjstra, Meerhoff, & Leffers, 2001; Jeevaratnam & Menon, 1996; Maas et al., 1997; Sakowitz, Raabe, Vucak, Kiening, & Unterberg, 2006) have been observed. There are obvious limitations to our present survey study, and in general, questionnaires may be difficult to interpret because of responder bias and generalizability of the questions. Another limitation is that some of the evaluated parameters may differ between patients with SAH and TBI. A strength of this report is that we obtained a 100% response frequency and the questions were straightforward to minimize interpretation bias. In four evaluated centers, unconscious patients with TBI and SAH were managed in general ICUs. Although it has been shown that the outcome is improved in patients with severe TBI managed in neurosurgical centers versus nonneurosurgical centers (Patel et al., 2005), it should be emphasized that all participating centers have 24-hour neurosurgical coverage. In the present report, we refrained from analyzing the impact of treatment and monitoring differences on patient outcome because of the inherent regional differences in patient factors, admission criteria, and preinjury and postinjury management factors. For NCC nurses, our data emphasize the lack of evidence or guidelines for many aspects of NCC care including the choice of monitoring technique besides ICP and CPP, the choice of analgesic and sedative drugs, and the frequency of the NWT. We argue that the observed difference in routine NCC among neurosurgical centers may pose a problem when attempting a multicenter evaluation of novel pharmacological compounds or treatment options. Likely, increased collaboration among NCC centers with the aim of developing common guidelines for the management of patients with SAH and TBI is warranted to improve the management of patients with severe brain injury.
In the present report, we evaluated differences in routine neurocritical care management of patients with severe TBI or SAH in 16 NCC centers. Although Scandinavia is a rather homogenous region with similar healthcare, there were marked differences among NCC centers, particularly with regard to choice of sedatives and the frequency of the NWT. These differences may reflect different clinical management traditions in many centers and the lack of evidence-based guidelines. We argue that these large differences in routine NCC may pose an obstacle for the establishment of novel treatment modalities for patients with TBI and SAH.
This work was sponsored by the Swedish Research Council and funds from the Uppsala University Hospital.
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Keywords:: monitoring; sedation; subarachnoid hemorrhage; traumatic brain injury; wake-up test
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