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Intracranial pressure monitoring and case mix-adjusted mortality in intracranial hemorrhage
Abstract
Intracranial pressure (ICP) monitoring is frequently used in intensive care treatment of patients with intracranial hemorrhage. Data demonstrating an improved outcome from this intervention are lacking. We analyzed standardized mortality ratios in patients with and without ICP monitoring to determine its efficacy.
A nonrandomized study of case records of consecutively admitted intensive care unit (ICU) patients with intracranial hemorrhage.
General and medical ICU of a 900-bed tertiary-care hospital.
A total of 225 patients with intracranial hemorrhage (mainly nontraumatic) admitted consecutively between April 1997 and March 2000.
Simplified Acute Physiology Score (SAPS) II, diagnosis, age, sex, use of ICP monitoring, and in-hospital mortality rates were collected from the hospital's ICU database. Expected mortality was provided by means of SAPS II. Standardized mortality ratios were calculated and compared in 119 patients with ICP monitoring and 106 patients without ICP monitoring.
The case mix-adjusted hospital mortality in the group with ICP monitoring was in the expected range (standardized mortality ratio, 1.09 [95% confidence interval (CI), 0.87-1.31]). Patients without ICP monitoring had a significantly higher standardized mortality ratio than expected (1.26 [95% CI, 1.06-1.46]).
A beneficial effect of ICP monitoring in patients with intracranial hemorrhage may be reflected in an improved standardized mortality ratio.
... A continuous neuromonitoring via intraparenchymal sensor allows assessment of pathological changes, prediction of outcome, and guidance throughout the treatment. Key parameters are particularly intracranial pressure (ICP) and brain tissue oxygen tension (ptiO 2 ) since several studies could show a benefit if monitored [2][3][4][5][6][7][8][9]. ...
... Several studies were able to show a reduced mortality linked to sole ICP monitoring [2][3][4][5]. However, other trials reported unchanged or even elevated mortality as well as prolonged duration of mechanical ventilation when ICP monitoring and guided therapy were applied [17][18][19]. ...
Background:
A novel multiparameter brain sensor (MPBS) allows the simultaneous measurement of brain tissue oxygenation (ptiO2), cerebral blood flow (CBF), intracranial pressure (ICP), and brain temperature with a single catheter. This laboratory investigation evaluates the MPBS in an animal model in relation to established reference probes.
Methods:
The study group consisted of 17 juvenile male pigs. Four MPBS and four reference probes were implanted per pig and compared simultaneously. The measured parameters were challenged by standardized provocations such as hyperoxia, dobutamine, and norepinephrine application, hypercapnia and hypoxia in combination with and without a controlled cortical impact (CCI) injury. Mean values over 2 min were collected for predefined time points and were analyzed using Bland-Altman plots.
Results:
The protocol was successfully conducted in 15 pigs of which seven received CCI. ICP and ptiO2 were significantly influenced by the provocations. Subtraction of MPBS from reference values revealed a mean difference (limits of agreement) of 3.7 (- 20.5 to 27.9) mm Hg, - 2.9 (- 7.9 to 2.1) mm Hg, and 5.1 (- 134.7 to 145.0) % for ptiO2, ICP, and relative CBF, respectively.
Conclusions:
The MPBS is a promising measurement tool for multiparameter neuromonitoring. The conducted study demonstrates the in vivo functionality of the probe. Comparison with standard probes revealed a deviation which is mostly analogous to other multiparameter devices. However, further evaluation of the device is necessary before it can reliably be used for clinical decision making.
... 3 Paciente com TCE grave e GCS com escore igual ou inferior a 08 indica-se à monitorização de PIC. 4 Com o uso desta monitorização contínua, em conjunto com a GCS, é possível traçar o possível prognóstico do paciente. [5][6][7] O aumento da PIC pode ser decorrente dos seguintes mecanismos: lesões expansivas na caixa craniana; obstrução do fluxo de saída do líquido cefalorraquidiano; aumento de líquido no espaço intersticial e/ou intracelular; engurgitamento. [8][9] Uma complicação importante em curto prazo é o edema cerebral do tecido lesado, o qual atinge seu grau máximo em 72 horas após o trauma. ...
... Os valores desejados da PAM nos casos com risco de HIC são de 60 a 180 mmHg. [4][5][6][7][8][9] A média obtida foi de 81,42 (±11,63) mmHg. Nos casos de hipotensão arterial e hipertensão arterial, a variação da PAM é prejudicial ao cérebro, portanto, deve ser evitada. ...
A fisioterapia dispõe de recursos específicos para a reabilitação em unidade de terapia intensiva (UTI), assim como nos pacientes com traumatismo cranioencefálico (TCE) grave. Entre essas técnicas, destaca- se a manobra de expansão pulmonar, que é uma técnica cinesioterapêutica, a qual tem função de mobilizar secreção pulmonar, prevenir e tratar atelectasias. Modelo do estudo: O estudo foi classificado como pesquisa de campo (experimental), baseada em avaliação da PIC durante e após a manobra de expansão pulmonar. Objetivo: Verificar a influência da manobra fisioterapêutica de expansão pulmonar nos valores da pressão intracraniana (PIC) em pacientes com TCE grave. Metodologia: A pesquisa foiaprovada pelo Comitê de Ética e Pesquisa da PUCPR, com o parecer 1455. Foi realizada na unidade de terapia intensiva (UTI) do Hospital Universitário Cajuru, Curitiba-PR. Participaram do estudo 15 pacientes de ambos os sexos, com TCE grave e com faixa etária entre 18 e 50 anos. As variáveis monitorizadas foram a PIC, a pressão arterial média (PAM) e a pressão de perfusão cerebral (PPC). Resultados: Durante a aplicação do protocolo de pesquisa observou-se que a PAM e a PPC mantiveram-se dentro ou próximos da normalidade com mínimas variações, enquanto que a PIC evolui com variação aproximada de 1 mmHg retornando aos valores iniciais. As médias da PIC no 1º dia, 2º dia e 3º dia foram 5,42 (±4,69) mmHg, 6,71 (±6,84) mmHg e 5,60 (±4,33) mmHg, com significância estatística respectivamente p
... Several studies have found increased mortality in ICU patients who develop AF, and arrhythmia was not reported to be the cause of death but to occur in the sicker patients with poor prognosis [1,2,4,5,6]. SMRs (risk adjusted mortality by SAPS II) provide a comparison of odds of dying after weighting for severity of illness; thus variations from expected mortality reflect the impact of various strategies and not a clinical preselection [23]. It can also be used to evaluate the impact of a pathological event on mortality. ...
... Similarly, one should be prudent with the results of the predictive hierarchical model as it has not been validated on an independent sample. Third, we limited the study to the evaluation of the first episode of AF occurring during the first 8 days of ICU hospitalization because it is well documented that AF usually occurs during the first days of hospitalization [4,5,6,23]. Finally, the therapeutic aspect of AF in ICUs was not studied specifically, and patients received a broad variety of treatments. ...
To evaluate the incidence and risk factors of atrial fibrillation (AF) in trauma patients.
Prospective observational study in a surgical intensive care unit (ICU).
All trauma patients admitted in the surgical ICU except those who had AF at admission.
AF occurred in 16/293 patients (5.5%). AF patients were older, had a higher number of regions traumatized, and received more fluid therapy, transfusion products, and catecholamines. They more frequently experienced systemic inflammatory response syndrome, sepsis, shock, and acute renal failure and had higher scores of severity (Simplified Acute Physiology Score, SAPS II; Injury Severity Score). ICU length of stay and resources use were also increased. ICU and hospital mortality rates were twice higher in AF patients whereas standardized mortality ratio (observed/expected mortality by SAPS II) was similar in the two groups. We found five independent risk factors of developing AF: catecholamine use (OR = 5.7, 95% CI 1.7-19.1), SAPS II of 30 or higher (OR = 11.6, 95% CI 1.3-103.0), three or more regions traumatized (OR = 6.2, 95% CI 1.8-21.4), age 40 years or higher (OR = 6.3, CI 1.4-28.7), and systemic inflammatory response syndrome (OR = 4.4, 95% CI 1.2-16.1).
In addition to age and catecholamine use, inflammation and severity of injury may be involved in the development of AF in trauma patients. Our results suggest that AF could rather be a marker of a higher severity of illness without major effect on mortality.
... [10][11][12] Long-sustained pressure phases should be avoided to protect affected and non-affected surrounding brain tissue from secondary deterioration or entrapment. [13][14][15][16] Clinical guideline recommendations for ICP thresholds can vary between groups of patients, but treatment of an elevated ICP should be initiated immediately in order to keep the periods of an elevated ICP as short as possible. [17][18][19] One of the most common reasons for an elevated ICP is cerebral oedema, which can develop focally or in a diffuse way. ...
The evolution of intracranial pressure (ICP) of critically ill patients admitted to a neurointensive care unit (ICU) is difficult to predict. Besides the underlying disease and compromised intracranial space, ICP is affected by a multitude of factors, many of which are monitored on the ICU, but the complexity of the resulting patterns limits their clinical use. This paves the way for new machine learning techniques to assist clinical management of patients undergoing invasive ICP monitoring independent of the underlying disease.
An institutional cohort (ICP-ICU) of patients with invasive ICP monitoring (n = 1346) was used to train recurrent machine learning models to predict the occurrence of ICP increases of ≥22 mmHg over a long (>2 h) time period in the upcoming hours. External validation was performed on patients undergoing invasive ICP measurement in two publicly available datasets [Medical Information Mart for Intensive Care (MIMIC, n = 998) and eICU Collaborative Research Database (n = 1634)].
Different distances (1–24 h) between prediction time point and upcoming critical phase were evaluated, demonstrating a decrease in performance but still robust AUC-ROC with larger distances (24 h AUC-ROC: ICP-ICU 0.826 ± 0.0071, MIMIC 0.836 ± 0.0063, eICU 0.779 ± 0.0046, 1 h AUC-ROC: ICP-ICU 0.982 ± 0.0008, MIMIC 0.965 ± 0.0010, eICU 0.941 ± 0.0025). The model operates on sparse hourly data and is stable in handling variable input lengths and missingness through its nature of recurrence and internal memory. Calculation of gradient-based feature importance revealed individual underlying decisions for our long short time memory-based model and thereby provided improved clinical interpretability.
Recurrent machine learning models have the potential to be an effective tool for the prediction of ICP increases with high translational potential.
... Our fi ndings agree with a number of previous studies that support the value of ICP monitoring in TBI, but contrast with several other studies that either failed to show an association between ICP monitoring and better outcomes, or showed an association between ICP monitoring and higher mortality. 20,26 Theonly randomized trial in this area showed no difference in the primaryoutcome, a compositemeasure based on performance across 21measures of functional and cognitive status, between care focused onmaintaining ICP at 20 mmHg or less and care based on imaging andclinical examination in the setting of the developing world, whereICP monitoring is very rarely used. However, the trial was notsuffi ciently powered to detect a mortality difference between bothgroups. ...
p>Intracranial pressure monitoring is considered the standard of care for severe traumatic brain injury and is used frequently. However, the efficacy of treatment based on monitoring in improving the outcome has not been rigorously assessed. We conducted a trial in which we included 26 patients of all types of traumatic brain injury (TBI) and they were monitored for intracranial pressure by Conventional fluid filled system with a manometer (Group 1) and compared with the Fiber optic transducer-tipped intracranial pressure monitoring system (Group 2).The main aim of this study was to examine the relationship between Intracranial Pressure (ICP) monitoring and in-hospital mortality. The median length of stay in the ICU was similar in the two groups (12 days in the conventional pressure-monitoring group and 9 days in the new fiber optic group; P=0.25), the number of days of brain-specific treatments (e.g., administration of hyperosmolar fluids and the use of hyperventilation) in the ICU was similar in both groups. The distribution of serious adverse events was similar in the two groups. We concluded that ICP monitoring (as is any monitoring modality) is a useful guide for management. The outcomes are decided by the differences in management protocols that the knowledge of the said parameter brings about. ICP monitoring is recommended for the better management of traumatic brain injury and fiber optic ICP monitoring seems to be beneficial than using the conventional methods of ICP monitoring with manometer.
Nepal Journal of Neuroscience, Volume 15, Number 2, 2018, page: 23-29</p
... However, the treatment should be applied with consideration of the underlying pathology/cause. Treatment for intracranial hypertension is aimed at reducing the volume of one of the three intracranial compartments: brain tissue, blood, and cerebrospinal fluid [11]. Management of intracranial hypertension should be initiated with prompt management of airway, breathing and circulation. ...
... ICP monitoring can assist in the management of patients with a variety of brain diseases. The technique has proven valuable, indeed often lifesaving, in the acute care of traumatic brain injury (TBI) [14], hydrocephalus [20], drowning [21], inflammatory and related cerebral diseases such as Reye's syndrome [22], hepatic failure [23], intracranial hemorrhage [24][25][26], and postoperative suboccipital brain tumors [27]. There is a conspicuous need for a wireless, implantable ICP monitoring system, as several chronic diseases are associated with intracranial hypertension (ICH). ...
Intracranial Pressure (ICP) monitoring is a significant tool that aids in the management of neurological disorders like hydrocephalus, head trauma, tumors, colloid cysts, cerebral hematomas etc. ICP is the pressure exerted on the rigid, bony skull by its constituents that are brain, cerebrospinal fluid, and the cerebral blood. Increased ICP can lead to brain damage, disability, and death. Various modalities have been developed for the monitoring of ICP in hospitals and in ambulatory conditions. Currently, only catheter based systems have made it to the clinical practice. The catheter based systems can only be used in a hospital setting, and have a limited useful life due to drift and risk of infection. The motivation for this research was the intent to develop a completely implantable, wireless ICP monitoring implant that can provide long-term monitoring of the pressure in ambulatory conditions. The uniqueness of this work is accentuated by the ability of the implant to transmit at 2.4 GHz. These implants have undergone a battery of tests in the in-vitro and invivo (canine) studies during which the feasibility of microwave transmission through scalp was established. Long-term animal studies were conducted to determine the integrity, biocompatibility, and the performance of the implant in a biological environment. Animal studies for long durations with epidural implants showed a thickening of the dura mater under sensor area. Therefore, the effect of dural thickness on the sensitivity of pressure sensing mechanism was simulated. The histo-pathological examination of the tissue specimens that were excised at the termination of an animal study showed the presence of lymphocytes, and fibrous tissue which is a normal immunological reaction to a foreign body. These tests did not reveal any toxicity due to the presence of the implant. In the animal studies that were conducted with sub-dural implants, a correlation coefficient of 0.94 and better was determined between the gold standard for ICP monitoring and our implant. In our latest animal study a sub-dural implant has been successfully tested in an animal for a duration of one month, thus proving the reliability of the implant packaging and its performance for a long-duration ICP monitoring application. This study also underscores the applicability of our ICP implant for monitoring of traumatic brain injuries, among other applications.
... ICP monitoring has been used in clinical practice for more than 4 decades, but evidence from randomized controlled trials in support of this intervention is lacking [31]. The first monitoring of intracranial pressure was described by Guillaume and Janny in 1951 using an indwelling intraventricular catheter attached to an external strain gauge transducer, amplifying system, and chart recorder [12]. ...
Intracranial pressure (ICP) monitoring has become standard in the management of neurocritical patients. A variety of monitoring techniques and devices are available, each offering advantages and disadvantages. Analysis of large populations has never been performed.
A prospective study was designed to evaluate the Camino fiberoptic intraparenchymal cerebral pressure monitor for complications and accuracy.
Between 1992-2004 one thousand consecutive patients had a fiberoptic ICP monitor placed. The most frequent indication for monitoring was severe head injury (697 cases). The average duration of ICP monitoring was 184.6 +/- 94.3 hours; the range was 16-581 hours. Zero drift (range, -17 to 21 mm Hg; mean 7.3 +/- 5.1) was recorded after the devices were removed from 624 patients. Mechanical complications such as: breakage of the optical fiber (n = 17); dislocations of the fixation screw (n = 15) or the probe (n = 13); and failure of ICP recording for unknown reasons (n = 4) were found in 49 Camino devices.
The Camino ICP sensor remains one of the most popular ICP monitoring devices for use in critical neurosurgical patients. The system offers reliable ICP measurements in an acceptable percentage of device complications and the advantage of in vivo recalibration. The incidence of technical complications was low and similar to others devices.
Direct monitoring of intracranial pressure can detect increases in pressure long before clinical signs become apparent. The two most commonly used methods are either an intraparenchymal monitor or an intraventricular catheter. The latter may be attached to an external transducer or have a pressure transducer within the lumen of the catheter. Intraventricular catheters have the advantage of being able to drain cerebrospinal fluid as a method of reducing intracranial pressure. Insertion of an intraparenchymal monitor can be easily performed by trained, non-neurosurgical staff. Although there is a lack of Class 1 evidence to support the measurement of intracranial pressure and the targeting of cerebral perfusion pressure in severe head injury, there is good evidence that the use of these as part of a protocol-based system of care on specialised units results in improvement in mortality and functional outcome following brain injury.
Introduction:
Literature remains sparse regarding decompressive craniectomy (DC) in traumatic brain injury (TBI) in very young children. This study analysed the indications, complications and outcome of young children undergoing DC for TBI at our institute.
Study design:
Retrospective.
Observations:
The total number of patients was 71. Mean age was 1.6 years. Mean duration from injury to surgery was 11.9 hours (range = 3-80 hours). Around 50% had severe head injury. Intracranial pressure (ICP) monitoring was done in 33 patients. Mean ICP was 22.2 mm Hg (range = 9-50 mm Hg). The threshold ICP for surgery was 15 mm Hg. Perioperative mortality was 50% each for severe TBI (18/36) and diffuse cerebral edema (7/14), and 58% for infants (4/7). Ninety per cent of expired patients had ICP > 20 mm Hg. Mean follow-up duration was 19.6 months (range = 2-42 months). Except one, all survivors had good-to-excellent outcomes (Glasgow outcome scale extended; GOS-E = 7-8).
Conclusions:
Decompressive craniectomy offers a survival advantage in almost 50% of young children with severe TBI and should be used judiciously. The highest mortality was within the 1st week of surgery. The cut-off limit of 20 mm Hg for surgical decompression might not be applicable to young children and a low threshold ICP needs to be considered. Factors associated with increased mortality are high opening ICP (>20 mm Hg), GCS <8, diffuse cerebral oedema and infant age group. Timing of DC remains crucial. Further prospective studies are necessary to optimize the timing and ICP limit for surgical decompression.
Objective:
To study the possibilities of common ultrasound diagnostic methods in the evaluation of intracranial pressure (ICP) and central perfusion pressure (CPP) and to search for the ways of increasing the accuracy of these methods.
Material and methods:
Thirty-eight patients, aged 28-66 years admitted to a neuroreanimation department of a hospital due to acute intracranial vascular and traumatic hemorrhages were examined. An instrumental study included transcranial dopplerography (TCDG) and digital echoencephalography. Accuracy of measurement was evaluated for ICP and CPP in clinical conditions.
Results:
The data obtained confirm the possibility of quantitative assessment of ICP and CPP using TCDG. We suggest a new formula for more precise calculation of CPP.
Conclusion:
The complex use of noninvasive ultrasound methods allow in most cases to measure with acceptable accuracy and assess the degree of intensity of ICP and CPP changes at the acute stage of intracranial hemorrhages.
Objective:
To study the brachiocephalic blood flow in patients after posterior fossa surgery in sitting position.
Material and methods:
We examined 60 patients (44 women and 16 men, mean age from 46.45±13.2 years) after the surgery of neurinomas and meningiomas. The study of neurological symptoms and cerebral blood flow as well as computed tomography of the brain were performed.
Results and conclusion:
No changes in the extracranial blood flow were found in patients without pneumocephalus or with a small amount of air in the intracranial cavity. Pneumocephalus decreased the linear velocity of the blood flow in the postoperative period. A trend towards the restoration of the blood flow along the inner carotid artery on both sides up to the preoperative level was found in patients with common pneumocephalus 24-48h after the surgery.
Intracranial pressure (ICP) is a product of the volume and compliance of the craniospinal contents. The craniospinal axis has only a limited capacity to accommodate any increase in volume without an increase in ICP. In the normal brain, autoregulation ensures that cerebral blood flow (CBF) remains constant even though cerebral perfusion pressure (CPP) can vary widely. In the diseased brain, autoregulation may be impaired such that CBF becomes pressure dependent. A fall in CPP, as such can result from elevation of ICP, results in a profound reduction in CBF.
Early identification and treatment of secondary injuries following acute brain injury is of benefit both in terms of mortality and morbidity. Elevation of ICP is an independent predictor of outcome from traumatic coma. Clinical assessment of ICP is difficult in unconscious patients and there is a poor correlation between the appearances on radiological imaging and direct measurement of ICP. Measurement of ICP and the targeting of therapies to reduce elevated ICP and preserve CPP are components in the management of severe brain injury.
Purpose
To analyse mortality for spontaneous intracerebral haemorrhage (ICH), myasthenia gravis (MG) and Guillain–Barré syndrome (GBS) from 1996 to 2009 in UK intensive care units (ICUs).
Methods
We used the Intensive Care National Audit & Research Centre (ICNARC) database. We identified specialised neurosciences critical care units (NCCUs) (n = 16), general ICUs with full neurological support (n = 48) and general ICUs with limited neurological support (n = 138) and undertook descriptive analyses for each condition. Poisson regression was used to identify trends in admission rates, median regression to identify trends in lengths of stay (LOS), and logistic regression (Wald test) to analyse interaction between unit type and time period; odds ratios were calculated for hospital mortality associated with unit types.
Results
For ICH (n = 10,313 cases), overall ICU mortality was 42.4 %, and acute hospital mortality 62.1 %. In NCCU, LOS was longer, but mortality lower, and over time, mortality from ICH decreased faster. For MG (n = 1,064 cases) and GBS (n = 1,906 cases), overall mortality was relatively high (MG: 8.7 % ICU mortality and 22 % acute hospital mortality; GBS: 7.7 and 16.7 %, respectively); overall mortality did not decrease over time.
Conclusions
This first large-scale analysis of outcomes in acute neurological disease in the UK demonstrates real-life mortality higher than published series. NCCU care is associated with increased survival in conditions requiring highly specialised intensive care techniques, but high-quality step-down care is pivotal in others. Strategies that truly improve outcomes must integrate emergency department management, ICU admission criteria, NCCU treatment, high-quality step-down care and neurorehabilitation.
Everyone interested in neuroanaesthesia talks about intracranial pressure (ICP), but in daily clinical practice nobody measures
it during craniotomy. This was the thesis that started this work more than ten years ago. A method for easy monitoring of
ICP during surgery, but before opening of dura, was devised and the method was introduced in our daily clinical practice.
In this chapter indications for ICP measurement, critical levels of ICP and regional differences in ICP are described. Medical
approaches to ICP control are considered, including body position, hyperventilation, hypothermia and administration of barbiturate.
The effect of suctioning, positive end-expiratory pressure, sedatives and analgetics are discussed as well as the use of mannitol
and hypertonic saline.
Patients with acute brain injury from various etiologies commonly develop increased intracranial pressure. Acute intracranial hypertension resulting from elevation of intracranial pressure is a medical emergency requiring prompt diagnosis and management. Appropriate and timely management strategies result in better patient outcome in an otherwise severely debilitating or fatal disease process.
The clinical manifestation and principles of management of acute intracranial hypertension are discussed and reviewed. Acute treatment protocols are presented in an algorithm-based format aimed at utilizing the current available management strategies and suggested therapeutic goals. Individualization of specific therapeutic modalities is emphasized to optimize the clinical outcome.
Clinicians treating patients with acute brain injury should be familiar with the principles of management of increased intracranial pressure. Since acute intracranial hypertension is a potentially reversible condition, high index of suspicion, and low threshold for diagnostic and therapeutic strategies will improve patient care.
Raised intracranial pressure (ICP) is a life threatening condition that is common to many neurological and non-neurological illnesses. Unless recognized and treated early it may cause secondary brain injury due to reduced cerebral perfusion pressure (CPP), and progress to brain herniation and death. Management of raised ICP includes care of airway, ventilation and oxygenation, adequate sedation and analgesia, neutral neck position, head end elevation by 20 degrees-30 degrees, and short-term hyperventilation (to achieve PCO(2) 32-35 mm Hg) and hyperosmolar therapy (mannitol or hypertonic saline) in critically raised ICP. Barbiturate coma, moderate hypothermia and surgical decompression may be helpful in refractory cases. Therapies aimed directly at keeping ICP <20 mmHg have resulted in improved survival and neurological outcome. Emerging evidence suggests that cerebral perfusion pressure targeted therapy may offer better outcome than ICP targeted therapies.
Increased intracranial pressure reflects the presence of mass effect in the brain and is associated with a poor outcome in children with acute neurological injury. If sustained, it has a negative effect on cerebral blood flow and cerebral perfusion pressure, can cause direct compression of vital cerebral structures, and can lead to herniation. The management of the patient with increased intracranial pressure involves the maintenance of an adequate cerebral perfusion pressure, prevention of intracranial hypertension, and optimization of oxygen delivery. This article reviews the neurological assessment, pathophysiology, and management of increased intracranial pressure in the critically ill child who has sustained an acute neurological injury.
Evidence suggests that the mortality and morbidity of acquired brain injury could be reduced if clinicians used an aggressive intracranial pressure guided approach to care. Despite nearly 50 years of evidence that intracranial pressure monitoring benefits patient care, only about half of the patients who could benefit are monitored. Some clinicians express concerns regarding risks such as bleeding, infections, and inaccuracy of the technology. Others cite cost as the reason. This article discusses the risks and benefits of intracranial pressure monitoring and the current state of evidence of why patients should be monitored.
Our main objective was to study the clinical outcome and complications of the subdural ICP monitoring with the CMS (Johnson and Johnson Medical Ltd, Raynhan, MA) in severe head injury.
A retrospective analysis of patients with head injury with a GCS score of 8 or less was performed. Patients with severe systemic injury with hypotension (systolic blood pressure of <90 mm Hg on admission), a GCS score of 3 with fixed and dilated pupils after resuscitation, a GCS score of 3 to 4 whose family refused aggressive treatment, and those who were dead on arrival were excluded from this study. During the period from January 1997 to April 2004, 120 patients with severe head injuries were included and met criteria for insertion of a subdural ICP monitoring device (CMS).
A total of 120 patients (84 males and 36 females), aged 16 to 80 years old (mean, 43.8 +/- 14.4), were enrolled in the study. The average duration of ICP monitoring device use was 7.6 +/- 0.4 days (range, 2-14 days). The overall clinical outcomes of these patients were as follows: mortality rate, 13.5%; percentage of unfavorable outcomes, 17.3%; percentage of favorable outcomes, 69.2%. There were no complications such as CNS infection or hemorrhage in this study.
A subdural transducer-tipped catheter (CMS) can be used as the first-line equipment for monitoring ICP in patients with severe head injury. The clinical results are similar with other recent studies, but no complication such as infection or hemorrhage occurred in this study.
Increased intracranial pressure (ICP) is an important cause of secondary brain injury, and ICP monitoring has become an established component of brain monitoring after traumatic brain injury. ICP cannot be reliably estimated from any specific clinical feature or computed tomography finding and must actually be measured. Different methods of monitoring ICP have been described but intraventricular catheters and microtransducer systems are most widely used in clinical practice. ICP is a complex variable that links ICP and cerebral perfusion pressure and provides additional information from identification and analysis of pathologic ICP wave forms. ICP monitoring can also be augmented by measurement of indices describing cerebrovascular pressure reactivity and pressure-volume compensatory reserve. There is considerable variability in the use of ICP monitoring and treatment modalities among head injury centers. However, there is a large body of clinical evidence supporting the use of ICP monitoring to detect intracranial mass lesions early, guide therapeutic interventions, and assess prognosis, and it is recommended by consensus guidelines for head injury management. There remains a need for a prospective, randomized, controlled trial to identify the value of ICP monitoring and management after head injury.
Guidelines for the management of severe head injury in adults as evolved by the European Brain Injury Consortium are presented and discussed. The importance of preventing and treating secondary insults is emphasized and the principles on which treatment is based are reviewed. Guidelines presented are of a pragmatic nature, based on consensus and expert opinion, covering the treatment from accident site to intensive care unit. Specific aspects pertaining to the conduct of clinical trials in head injury are highlighted. The adopted approach is further discussed in relation to other approaches to the development of guidelines, such as evidence based analysis.
To compare the performance of the New Simplified Acute Physiology Score (SAPS II) and the New Admission Mortality Probability Model (MPM II0) within relevant subgroups using formal statistical assessment (uniformity of fit).
Analysis of the database of a multi-centre, multi-national and prospective cohort study, involving 89 ICUs from 12 European Countries.
Database of EURICUS-I.
Data of 16,060 patients consecutively admitted to the ICUs were collected during a period of 4 months. Following the original SAPS II and MPM II0 criteria, the following patients were excluded from the analysis: younger than 18 years of age; readmissions; acute myocardial infarction; burn cases; patients in the post-operative period after coronary artery bypass surgery and patients with a length of stay in the ICU shorter than 8 h, resulting in a total of 10,027 cases.
Data necessary for the calculation of SAPS II and MPM II0, basic demographic statistics and vital status on hospital discharge were recorded. Formal evaluation of the performance of the models, comprising discrimination (area under ROC curve), calibration (Hosmer-Lemeshow goodness-of-fit H and C tests) and observed/expected mortality ratios within relevant subgroups.
Better predictive accuracy was achieved in elective surgery patients admitted from the operative room/post-anaesthesia room with gastrointestinal, neurological or trauma diagnoses, and younger patients with non-operative neurological, septic or trauma diagnoses. All these characteristics appear to be linked to a lower severity of illness, with both models overestimating mortality in the more severely ill patients.
Concerning the performance of the models, very large differences were apparent in relevant subgroups, varying from excellent to almost random predictive accuracy. These differences can explain some of the difficulties of the models to accurately predict mortality when applied to different populations with distinct patient baseline characteristics. This study stresses the importance of evaluating multiple diverse populations (to generate the design set) and of methods to improve the validation set before extrapolations can be made from the validation setting to new independent populations. It also underlines the necessity of a better definition of the patient baseline characteristics in the samples under analysis and the formal statistical evaluation of the application of the models to specific subgroups.
Objective.
—To develop and validate a new Simplified Acute Physiology Score, the SAPS II, from a large sample of surgical and medical patients, and to provide a method to convert the score to a probability of hospital mortality.Design and Setting.
—The SAPS II and the probability of hospital mortality were developed and validated using data from consecutive admissions to 137 adult medical and/or surgical intensive care units in 12 countries.Patients.
—The 13 152 patients were randomly divided into developmental (65%) and validation (35%) samples. Patients younger than 18 years, burn patients, coronary care patients, and cardiac surgery patients were excluded.Outcome Measure.
—Vital status at hospital discharge.Results.
—The SAPS II includes only 17 variables: 12 physiology variables, age, type of admission (scheduled surgical, unscheduled surgical, or medical), and three underlying disease variables (acquired immunodeficiency syndrome, metastatic cancer, and hematologic malignancy). Goodness-of-fit tests indicated that the model performed well in the developmental sample and validated well in an independent sample of patients (P=.883 and P=.104 in the developmental and validation samples, respectively). The area under the receiver operating characteristic curve was 0.88 in the developmental sample and 0.86 in the validation sample.Conclusion.
—The SAPS II, based on a large international sample of patients, provides an estimate of the risk of death without having to specify a primary diagnosis. This is a starting point for future evaluation of the efficiency of intensive care units.(JAMA. 1993;270:2957-2963)
Recently, a renewed emphasis has been placed on managing severe head injury by elevating cerebral perfusion pressure (CPP), which is defined as the mean arterial pressure minus the intracranial pressure (ICP). Some authors have suggested that CPP is more important in influencing outcome than is intracranial hypertension, a hypothesis that this study was designed to investigate.
The authors examined the relative contribution of these two parameters to outcome in a series of 427 patients prospectively studied in an international, multicenter, randomized, double-blind trial of the N-methyl-D-aspartate antagonist Selfotel. Mortality rates rose from 9.6% in 292 patients who had no clinically defined episodes of neurological deterioration to 56.4% in 117 patients who suffered one or more of these episodes; 18 patients were lost to follow up. Correspondingly, favorable outcome, defined as good or moderate on the Glasgow Outcome Scale at 6 months, fell from 67.8% in patients without neurological deterioration to 29.1% in those with neurological deterioration. In patients who had clinical evidence of neurological deterioration, the relative influence of ICP and CPP on outcome was assessed. The most powerful predictor of neurological worsening was the presence of intracranial hypertension (ICP > or = 20 mm Hg) either initially or during neurological deterioration. There was no correlation with the CPP as long as the CPP was greater than 60 mm Hg.
Treatment protocols for the management of severe head injury should emphasize the immediate reduction of raised ICP to less than 20 mm Hg if possible. A CPP greater than 60 mm Hg appears to have little influence on the outcome of patients with severe head injury.
The comparative efficacy of various treatment algorithms in improving outcome from severe head injury (SHI) has never been tested in a prospective, randomized, controlled trial. Indeed, there are few hard data on the influence on outcome of most of the individual treatment modalities used alone. The medical management algorithm presented here is an exercise in evaluating the strength of what studies do exist and attempting to balance the relative risk/benefit ratios of the various treatment modalities. This algorithm, based on the information contained in this issue of New Horizons, divides the patient's course into two segments based on the insertion of an intracranial pressure (ICP) monitor. Before the establishment of ICP monitoring, based on the devastating effects of secondary insults on the injured brain, the main emphasis should be on full resuscitation of the patient. Any "prophylactic" treatment of the intracranial injury that has the potential of interfering with full resuscitation (e.g., mannitol) or inducing secondary ischemic insults (e.g., hyperventilation) should be reserved for the specific instance of evidence of herniation or neurologic deterioration; if such deterioration should occur, however, it should be promptly treated. Following computed tomography imaging and any necessary surgical procedures, and ICP monitor should be inserted and treatment directed specifically toward controlling ICP and maintaining a cerebral perfusion pressure > or = 70 mm Hg. An algorithm for treating intracranial hypertension is presented, based on the successive application of effective agents with increasing attendant risks. Outside of the burgeoning pharmacologic approaches to the injured brain, the future of the management of SHI involves: a) subjecting the various protocols and treatment modalities presently in use to prospective, randomized, controlled trials in order to formally establish their utility; b) developing organized, regionalized trauma care systems which facilitate the universal delivery of the level of care necessary to effectively apply today's head injury management protocols; and c) furthering our development of targeted therapy in treating SHI. Targeted therapy involves recognizing and understanding the various pathophysiologic processes that occur in the injured brain over the acute course of treatment and the responses of these processes to various treatment modalities. Such processes include vasogenic and cytotoxic edema, increased cerebral blood volume, altered cerebrovascular autoregulation, vasospasm, etc.(ABSTRACT TRUNCATED AT 400 WORDS)
To develop and validate a new Simplified Acute Physiology Score, the SAPS II, from a large sample of surgical and medical patients, and to provide a method to convert the score to a probability of hospital mortality.
The SAPS II and the probability of hospital mortality were developed and validated using data from consecutive admissions to 137 adult medical and/or surgical intensive care units in 12 countries.
The 13,152 patients were randomly divided into developmental (65%) and validation (35%) samples. Patients younger than 18 years, burn patients, coronary care patients, and cardiac surgery patients were excluded.
Vital status at hospital discharge.
The SAPS II includes only 17 variables: 12 physiology variables, age, type of admission (scheduled surgical, unscheduled surgical, or medical), and three underlying disease variables (acquired immunodeficiency syndrome, metastatic cancer, and hematologic malignancy). Goodness-of-fit tests indicated that the model performed well in the developmental sample and validated well in an independent sample of patients (P = .883 and P = .104 in the developmental and validation samples, respectively). The area under the receiver operating characteristic curve was 0.88 in the developmental sample and 0.86 in the validation sample.
The SAPS II, based on a large international sample of patients, provides an estimate of the risk of death without having to specify a primary diagnosis. This is a starting point for future evaluation of the efficiency of intensive care units.
This paper considers an index of hospital quality performance defined as the ratio of the observed number deaths to the number predicted by a fitted logistic regression model. We study tests and confidence intervals under two different scenarios depending on the availability of an estimate of the covariance matrix of the coefficients from the fitted logistic regression model. We propose parametric as well as bootstrap-based confidence intervals. We apply the methods to an analysis of the performance of 27 intensive care units.
Guidelines for the management of severe head injury in adults as evolved by the European Brain Injury Consortium are presented and discussed. The importance of preventing and treating secondary insults is emphasized and the principles on which treatment is based are reviewed. Guidelines presented are of a pragmatic nature, based on consensus and expert opinion, covering the treatment from accident site to intensive care unit. Specific aspects pertaining to the conduct of clinical trials in head injury are highlighted. The adopted approach is further discussed in relation to other approaches to the development of guidelines, such as evidence based analysis.
To assess the performance of general severity systems (Acute Physiology and Chronic Health Evaluation [APACHE] II, Simplified Acute Physiology Score [SAPS] II, and Mortality Probability Models [MPM] II) for head trauma patients and to compare these systems with the Glasgow Coma Score, in order to obtain a good estimate of severity of illness and probability of hospital mortality.
Inception cohort.
Adult medical and surgical intensive care units in 12 European and North American countries.
Patients (n = 401) who were diagnosed with head trauma (with/without multiple trauma), leading to intensive care unit admission, and who were not brain dead at the time of arrival.
Statistical analysis to assess the performance of general severity systems.
Vital status at the time of hospital discharge was the outcome measure. Performance of the severity systems (SAPS II, MPM II0 [MPM at admission], MPM II24 [MPM at 24 hrs], and APACHE II) was assessed by evaluating calibration and discrimination. Logistic regression was used to convert the Glasgow Coma Score into a probability of death. The MPM II system (either MPM II0 or MPM 1124) provided an adequate estimation of the mortality experience in patients with head trauma. SAPS II and APACHE II systems did not calibrate well, although they showed high discrimination (area under the receiver operating characteristic curve 0.95 for SAPS II, 0.94 for APACHE II, and 0.90 for MPM II0 and MPM II24). The logistic regression model containing the Glasgow Coma Score as an independent variable and developed in this group of patients was not as well calibrated as MPM II. The discrimination of this model was very high, in the range observed for the APACHE II, SAPS II, and MPM II systems.
The MPM II system performs better than APACHE II, SAPS II, and Glasgow Coma Score for head trauma patients. If our results are supported by other studies, MPM II would be an appropriate tool to assess severity of illness in head trauma patients, with applications to clinical practice and clinical research.
To evaluate the ability of an interdisciplinary data set (recently defined by the Austrian Working Group for the Standardization of a Documentation System for Intensive Care [ASDI]) to assess intensive care units (ICUs) by means of the Simplified Acute Physiology Score II (SAPS II) for the severity of illness and the simplified Therapeutic Intervention Scoring System (TISS-28) for the level of provided care.
A prospective, multicentric study.
Nine adult medical, surgical, and mixed ICUs in Austria.
A total of 1234 patients consecutively admitted to the ICUs.
Collection of data for the ASDI data set.
The overall mean SAPS II score was 33.1+/-2.1 points. SAPS II overestimated hospital mortality by predicting mortality of 22.2%+/-2.9%, whereas observed mortality was only 16.8%+/-2.2%. The Hosmer-Lemeshow goodness-of-fit test for SAPS II scores showed lacking uniformity of fit (H = 53.78, 8 degrees of freedom; p < .0001). TISS-28 scores were recorded on 8616 days (30.6+/-1.5 points). TISS-28 scores were higher in nonsurvivors than in survivors (30.4+/-0.9 vs. 25.7+/-0.4, respectively; p < .05). No significant correlation between mean TISS-28 per patient per unit on the day of admission and mean predicted hospital mortality (r2 = .23; p < .54) or standardized mortality ratio per unit (r2 = -.22; p < .56) was found.
Implementation of an interdisciplinary data set for ICUs provided data with which to evaluate performance in terms of severity of illness and provided care. The SAPS II did not accurately predict outcomes in Austrian ICUs and must, therefore, be customized for this population. A combination of indicators for both severity of illness and amount of provided care is necessary to evaluate ICU performance. Further data acquisition is needed to customize the SAPS II and to validate the TISS-28.
The purpose of this study was to obtain information from Canadian neurosurgeons regarding their opinions on, and utilization of, intracranial pressure (ICP) monitoring for severe traumatic brain injury (TBI).
A brief survey was sent to practicing Canadian neurosurgeons questioning them about their utilization of, and confidence in, intracranial pressure monitoring in the management of patients with severe TBI.
One hundred and ninety-six surveys were mailed. There were 103 responses for a response rate of 52.6%. The vast majority of responding neurosurgeons (98.1%) utilized ICP monitoring in the management of patients with severe TBI, with most (63.4%) using it in more than 75% of their patients, 14.9% using it in 50-75% of patients, 14.9% in 25-50% of patients, and 6.9% using it in less than 25% of patients. The level of confidence that routine monitoring improves outcome from severe TBI ranged from 23.3% having a low level of confidence, 56.3% having an intermediate level of confidence, to 20.4% having a high level of confidence. Most respondents (78.6%) felt that some form of prospective trial evaluating the role of ICP monitoring in improving outcome from severe TBI was warranted; 17.4% felt such a trial was not warranted and 3.9% were uncertain.
While ICP monitoring has gained almost universal acceptance among responding Canadian neurosurgeons, their level of confidence that routine monitoring improves outcome from severe TBI was quite variable, with only 20.4% of respondents having a high level of confidence. Over 75% of respondents felt that some form of prospective trial evaluating the utility of ICP monitoring is warranted. This information is being used in consideration of a prospective trial addressing this issue.
In 1886, Victor Horsley excised an epileptogenic posttraumatic cortical scar in a 23-year-old man under general anaesthesia and discussed his choice of anaesthesia: "I have not employed ether in operations on man, fearing that it would tend to cause cerebral excitement; chloroform, of course, producing on the contrary, well-marked depression." His concerns regarding anaesthesia are reiterated 100 years later as evidenced by the ongoing controversy over the choice of anaesthetic in surgical procedures for epilepsy. The current controversies regarding the necessity for local anaesthesia in temporal lobe epilepsy operations concern the utility of electrocorticography in surgical decision making, its relationship to seizure outcome and the value of intraoperative language mapping in dominant temporal lobe resections. The increasing sophistication of pre-operative investigation and localization of both areas of epileptogenesis and normal brain function and the introduction of minimally invasive surgical techniques and smaller focal resections are changing the indications for local anaesthesia in temporal lobe epilepsy. Thus, indications which were previously absolute are now perhaps relative. This article reviews the current indications for craniotomy under local anaesthesia in the surgical treatment of temporal lobe epilepsy.
To validate SAPS II-AM, a recently customized version of the Simplified Acute Physiology Score II (SAPS II) in a larger cohort of Austrian intensive care patients and to evaluate the effect of the customization process on the ratio of observed to expected mortality.
Prospective, multicentric cohort study.
A total of 2,901 patients consecutively admitted to 13 adult medical, surgical, and mixed intensive care units (ICUs) in Austria.
After the database was divided randomly into a development sample (n = 1,450) and a validation sample (n = 1,451), logistic regression was used to develop a new model (SAPS II-AM2). The original SAPS II, the SAPS IIAM, and the newly developed SAPS II-AM2 were then compared by means of calibration, discrimination and O/E ratios. Differences in O/E ratios before and after customization (deltaO/E) were calculated. The Hosmer-Lemeshow goodness-of-fit H and C statistics revealed poor calibration of the original SAPS II on the database. The new model, SAPS II-AM2, performed better than the SAPS II-AM and excellent in the validation data set. However, mean O/E ratios varied widely among diagnostic categories (range 0.55-1.05 for the SAPS II). Moreover, the deltaO/E of the 13 ICUs ranged from -3.6 % to +25 %.
Today's severity scoring systems, such as the SAPS II, are limited by not measuring (and adjusting for) a profound part of what constitutes case mix. Changes in the distribution of patient characteristics (known and unknown) therefore affect prognostic accuracy. First-level customization was not able to solve all these problems. Using O/E ratios for quality of care comparisons one must therefore be critical when using these data and should search for possible confounding factors. In the case of unsatisfactory calibration, customized severity of illness models may be useful as an adjunct for quality control.
(a) to describe current practice in the monitoring and treatment of moderate and severe head injuries in Europe; (b) to report on intracranial pressure and cerebral perfusion pressure monitoring, occurrence of measured and reported intracranial hypertension, and complications related to this monitoring; (c) to investigate the relationship between the severity of injury, the frequency of monitoring and management, and outcome.
A three-page questionnaire comprising 60 items of information has been compiled by 67 centres in 12 European countries. Information was collected prospectively regarding all severe and moderate head injuries in adults (> 16 years) admitted to neurosurgery within 24 h of injury. A total of 1005 adult head injury cases were enrolled in the study from 1 February 1995 to 30 April 1995. The Glasgow Outcome Scale was administered at 6 months.
Early surgery was performed in 346 cases (35%); arterial pressure was monitored invasively in 631 (68%), ICP in 346 (37%), and jugular bulb saturation in 173 (18%). Artificial ventilation was provided to 736 patients (78%). Intracranial hypertension was noted in 55% of patients in whom ICP was recorded, while it was suspected in only 12% of cases without ICP measurement. There were great differences in the use of ventilation and CPP monitoring among the centres. Mortality at 6 months was 31%. There was an association between an increased frequency of monitoring and intervention and an increased severity of injury; correspondingly, patients who more frequently underwent monitoring and ventilation had a less favourable outcome.
In Europe there are great differences between centres in the frequency of CPP monitoring and ventilatory support applied to head-injured patients. ICP measurement disclosed a high rate of intracranial hypertension, which was not suspected in patients evaluated on a clinical basis alone. ICP monitoring was associated with a low rate of complications. Cases with severe neurological impairment, and with the worse outcome, were treated and monitored more intensively.