Neurosurgery Intensive Care Unit Research Articles

Brain tissue PO 2, PCO 2, and pH during cerebral vasospasm

BACKGROUND The purpose of the present study was to assess brain tissue monitoring for detection of ischemia due to vasospasm in aneurysmal subarachnoid hemorrhage (SAH) patients. METHODS After obtaining informed consent, a burr hole was made in 10 patients and a Neurotrend 7 probe was inserted ipsilateral to the region of SAH. In eight patients the probe was inserted during surgery for clipping the aneurysm and in two patients the probe was inserted in the neurosurgery ICU. Brain tissue gases and pH were collected over 6-hour periods for 7 to 10 days until the termination of monitoring. The onset of vasospasm was confirmed by angiography and xenon computed tomography (Xe/CT) cerebral blood flow studies. RESULTS Seven patients did not develop vasospasm during monitoring and were considered as controls. In this group, brain tissue oxygen pressure (PO 2) remained above 20 mmHg, carbon dioxide pressure (PCO 2) stabilized at 40 mmHg and pH remained between 7.1 and 7.2. In three patients who developed vasospasm during monitoring, PO 2 was not different from the control group. However, PCO 2 increased to 60 mmHg and pH decreased to 6.7 ( p < 0.001). CONCLUSION In this study, patients with SAH who developed vasospasm had significantly lower brain tissue pH and higher PCO 2 compared to controls. However, there was no significant change in PO 2 levels associated with vasospasm. Brain tissue monitoring can provide an indication of ischemia during vasospasm.

Clinical usefulness of bedside intracranial morphological monitoring: mobile computerized tomography in the neurosurgery intensive care unit

The practice of modern neurointensive care is based on the use of multimodality monitoring to respond rapidly to physiological, biochemical, or morphological changes and avoid secondary brain injury. Until recently, one important monitoring method, computerized tomography (CT), has not been available for bedside use. The authors have over 3 years of experience with the routine use of bedside CT scanning and have developed their own method of scanning the patients in their beds. In this report, they describe three illustrative cases in which the mobile CT scanner was of great value in the management of difficult neurosurgical intensive care problems. It is concluded that the availability of bedside morphological monitoring in the neurosurgery intensive care unit is of great help in management and clinical decision making.

Mobile computerized tomography scanning in the neurosurgery intensive care unit: increase in patient safety and reduction of staff workload.

Transportation of unstable neurosurgical patients involves risks that may lead to further deterioration and secondary brain injury from perturbations in physiological parameters. Mobile computerized tomography (CT) head scanning in the neurosurgery intensive care (NICU) is a new technique that minimizes the need to transport unstable patients. The authors have been using this device since June 1997 and have developed their own method of scanning such patients. The scanning procedure and radiation safety measures are described. The complications that occurred in 89 patients during transportation and conventional head CT scanning at the Department of Radiology were studied prospectively. These complications were compared with the ones that occurred during mobile CT scanning in 50 patients in the NICU. The duration of the procedures was recorded, and an estimation of the staff workload was made. Two patient groups, defined as high- and medium-risk cases, were studied. Medical and/or technical complications occurred during conventional CT scanning in 25% and 20% of the patients in the high- and medium-risk groups, respectively. During mobile CT scanning complications occurred in 4.3% of the high-risk group and 0% of the medium-risk group. Mobile CT scanning also took significantly less time, and the estimated personnel cost was reduced. Mobile CT scanning in the NICU is safe. It minimizes the risk of physiological deterioration and technical mishaps linked to intrahospital transport, which may aggravate secondary brain injury. The time that patients have to remain outside the controlled environment of the NICU is minimized, and the staff's workload is decreased.

Predictors of mortality in stroke patients admitted to an intensive care unit.

Improved pathophysiologic insight and prognostic information regarding in-hospital risk of mortality among stroke patients admitted to an intensive care unit. Retrospective analysis. Neurology/neurosurgery intensive care unit in a tertiary care university medical center. A total of 63 consecutive ischemic stroke patients. Patients were classified according to in-hospital mortality. Charts were reviewed to retrospectively generate an admitting Acute Physiology and Chronic Health Evaluation (APACHE) II score. The APACHE II score and its individual components were assessed for predicting subsequent death. Of 63 patients, 13 died and 50 survived to either discharge or surgical intervention. The mean admitting APACHE II score of survivors (6.9) was lower than that of patients who died (17.2; p < .0001). None of the 33 patients with a score <9 died, compared with 43% of those with a score > or =9. A score > or =18 was uniformly associated with fatal outcome (n = 8). Univariate analysis identified APACHE II total score, Glasgow Coma Scale score, temperature, pH, and white blood cell count as significant predictors of death. Among multivariate logistic regression models examining the components of the APACHE II score, the model containing white blood cells, temperature, and creatinine best predicted death. Several features of the APACHE II score are associated with risk of death in this patient population. The findings suggest particular physiologic derangements that are associated with, and may contribute to, increased mortality in critically ill patients with acute ischemic stroke.

Nosocomial Infections in a Neurosurgery ICU

Nosocomial Infections in a Neurosurgery ICU

Nosocomial Infections in a Neurosurgery Intensive Care Unit

In order to identify overall and site-specific nosocomial infection (NI) rates in patients receiving neurosurgical intensive care therapy, a prospective study was started in February 1997 in the eight-bed neurosurgical ICU of the University Hospital of Freiburg, Germany. Case records were reviewed twice a week, all microbiology reports were reviewed and ward staff was consulted. NI were defined according to the CDC-criteria and were categorised into specific infection sites. Within 20 months, 545 patients with a total of 5,117 patient days were investigated (mean length of stay: 9.4 days). 113 NI were identified in 90 patients (72 pts. with one, 13 with two and 5 with three infections, respectively). A moderate to high overall incidence (20.7/100 pts.) and a moderate incidence density (22.1/1,000 patient days) of NI in the neurosurgical ICU could be documented; these figures are well within the range of published data. Site specific incidence rates and incidence densities were: 1 bloodstream infection per 100 patients (0.9 central line-associated BSIs per 1,000 central line-days), 9 pneumonias per 100 patients (15.1 ventilator-associated pneumonias per 1,000 ventilator-days), 7.3 urinary tract infections per 100 patients (8.5 urinary catheter-associated UTIs per 1,000 urinary catheter-days). Additionally, 1.1 cases of meningitis, 0.7 brain abscesses/ventriculitis, and 1.7 other infections (surgical site infection, bronchitis, catheter related local infection, diarrhoea) were documented per 100 patients, respectively. 14.6% of isolated pathogens were E. coli, 10.2% enterococci, 9.6% S. aureus, 6.4% CNS, 6.4% Klebsiella spp., 5% Enterobacter spp. and 5% Pseudomonas spp. In 11 cases of NI no pathogen could be isolated.

Application of transcranial doppler ultrasonography for the diagnosis of brain death.

To determine the clinical validity of transcranial Doppler ultrasonographic (TCD) signs of total cerebral circulatory arrest for confirmation of brain death and to define the test protocol. Study of a diagnostic test. General and neurosurgery intensive care units. 137 patients in a coma (Glasgow Coma Score 3-5), caused by various pathological conditions, observed from January 1992 to July 1998. 84 patients met the clinical criteria of brain death; 43 patients out of 137 received sedative drug therapy and 31 of these developed brain death. Total cerebral circulatory arrest was demonstrated by TCD in 81 patients. All of them proved to be brain dead according to subsequent clinical examination In 29 of 31 patients who had received sedative drug therapy TCD examination showed total cerebral circulatory arrest 12-48 h before the formal confirmation of the diagnosis. In 1 out of 84 clinically brain dead patients a false negative result was obtained. In 2 of 84 cases, no clear signals from intracranial vessels were obtainable. Fifty-three patients who did not meet the clinical criteria for brain death showed no TCD signs of total cerebral circulatory arrest. The specificity of the TCD test for confirmation of brain death was 100 % and the sensitivity 96.5 %. In agreement with previously published data, we conclude that TCD ultrasonography is a highly specific and sensitive confirmatory test and should be included as an additional test in the protocol for the assessment of brain death.

Multi-resistant Pseudomonas aeruginosa outbreak associated with contaminated tap water in a neurosurgery intensive care unit

From July 1995 to November 1996, multi-resistant Pseudomonas aeruginosa O11 was isolated from 36 patients admitted to a neurosurgery intensive care unit. The strain was resistant to ticarcillin, ceftazidime, imipenem, gentamicin and ciprofloxacin, and susceptible to amikacin. Nine patients were colonized only; the remaining 27 patients had at least one infected site (17 urinary infections, 10 pneumonias and four with sinusitis). P. aeruginosa O11 with the same resistance pattern was isolated from tap water. The strain was also cultured from enteral nutrition solutions given to two infected patients. DNA macrorestriction analysis with XbaI established the similarity of the isolates from patients, tap water and solutions. The outbreak was controlled after reinforcement of isolation procedures for infected patients, changing the mode of enterai nutrition and replacement of all sinks in the unit. The sinks were presumably the main source of P. aeruginosa during this outbreak, via the hands of the nursing staff or nutrition solutions contaminated with tap water.

Does modification of the Innsbruck and the Glasgow Coma Scales improve their ability to predict functional outcome?

The accurate prediction of functional outcome requires the development of multivariate models. To enhance their contribution to such models, the predictive power of each component must be optimized. To improve the predictive power of coma scales as the first step in building more sophisticated multivariate models to predict specific levels of functional outcome. Prospective descriptive study. Neurology and neurosurgery intensive care unit (NNICU) in a tertiary care academic center. Eighty-four patients with acute traumatic brain injury, intracerebral hemorrhage, subarachnoid hemorrhage, or ischemic stroke. None. The Glasgow Coma Scale (GCS) and Innsbruck Coma Scale (ICS) were administered within 24 hours of admission to the NNICU and then at 48-hour intervals until discharge of the patient from the NNICU. The assessments were performed by 3 occupational therapy graduate students working under the supervision of the medical director of the NNICU. The functional outcome at 3 months after discharge from the hospital was assessed by telephone by the same nurse using the following categories: (1) dead, (2) receiving nursing home or custodial care, (3) home with help, or (4) independent. Cronbach's alpha estimates of reliability for each scale were computed using all scores obtained during the study. The analyses indicated that the verbal response item of the GCS and the oral automatisms item of the ICS were less reliable in this patient population. The scales were modified by deleting those items, and predictive validity for the original and modified scales was computed using a discriminant function of the admission scores. Before modification, both scales were best at predicting independence (GCS and ICS, 71% correct) and mortality (GCS, 60% correct; ICS, 56% correct). The modifications produced a modest improvement in the ability of both scales to better predict levels of outcome (modified GCS: home with help, 33% correct, independent, 71% correct; modified ICS: home with help, 0% correct, independent, 74% correct). By deleting items with low reliability from the ICS and the GCS we achieved improved reliability and predictive validity. The improvement in predictive power, however, was inadequate to accurately predict functional outcome. Combining clinical scales with other demographic, physiological, functional, and radiographic data will be needed to achieve useful predictions of functional outcome.

Usefulness of near-infrared spectroscopy for monitoring a cerebral tissue oxygen saturation during cardio-pulmonary resuscitation (CPR)

Near-infrared spectroscopy has been verified to be a reliable monitoring method in detecting a regional cerebral tissue oxygen saturation (rSO2) in the field of neurosurgery, cardiovascular surgery and neonatal ICU. Cerebral tissue oxygenation is promptly and continuously monitored during resuscitation, and moreover, we can compare the efficacy among the resuscitation techniques with this method.

Remote analysis of physiological data from neurosurgical ICU patients.

Recent technical advances in Internet-based client/server applications and new multimedia communications protocols are enabling the development of cost-effective, platform-independent solutions to the problem of remote access to continuously acquired physiological data. The UCLA Neurosurgery Intensive Care Unit (ICU) has developed a distributed computer system that provides access over the World Wide Web (WWW) to current and previously acquired physiological data, such as intracranial pressure, cerebral perfusion pressure, and heart rate from critical care patients. Physicians and clinical researchers can access these data through personal computers from their offices, from their homes, or even while on the road. The system creates and continuously updates a database of all monitored parameters in data formats that can readily be used for further clinical studies. This paper describes an extension to this system that allows for remote interaction with and analysis of the data via the WWW. Physicians can now pose a limited, predefined set of clinically relevant questions to the system without having to be at the patient's bedside.

Serratia marcescens nosocomial outbreak due to contamination of hexetidine solution

During a 10-week period, 16 patients in a neurosurgery intensive care unit were involved in an outbreak of Serratia marcescens. The epidemic strain was found in several flasks of 1:4 diluted hexetidine solution, an antiseptic used for patient mouth washing. Testing of the bactericidal activity of the diluted antiseptic revealed that all the epidemic strains were able to grow in the diluted antiseptic solution. Strains isolated from clinical samples and from the antiseptic solution were compared by random amplification of polymorphic DNA. Epidemiologic typing data implicated the diluted antiseptic solution as the single source of this S. marcescens outbreak.

Nutritional and metabolic variables correlate with amino acid forearm flux in patients with severe head injury

To measure the arterial-venous amino acid flux across the forearm muscle in patients with severe head injury. Prospective, interventional study. Level I trauma hospital in the neurosurgery intensive care unit (ICU) at a university medical center. Eight nonsteroid-treated patients with severe head injury. Patients were prospectively randomized to receive either standard or supplemental intravenous zinc therapy. Net forearm alanine, glutamine, tyrosine, phenylalanine, and branch-chain amino acid forearm flux were measured and compared with metabolic markers of energy expenditure and nitrogen excretion. There was a significant inverse relationship between the measured energy expenditure/predicted energy expenditure ratio and glutamine flux (r2 = .62; p < .05). The patients with the highest measured energy expenditure/predicted energy expenditure ratio had the greatest release of glutamine from forearm muscle. Nitrogen balance was significantly correlated with leucine flux (r2 = .53; p < .05) and with isoleucine flux (r2 = .67; p < .05). The patients with the most positive nitrogen balance had the least release of branch-chain amino acids from skeletal muscle. Tyrosine flux was highly correlated with net amino acid flux (r2 = .76; p < .01). Tyrosine flux was therefore indicative of overall muscle catabolism. Four patients had an overall negative flux of amino acids from skeletal muscle. Three patients had an overall negative flux of branch-chain amino acids. This preliminary descriptive report suggests that increased skeletal muscle efflux of amino acids correlates significantly with metabolic variables of hypermetabolism and hypercatabolism in nonsteroid-treated, head-injured patients.

IDENTIFYING NEUROLOGIC COMPLICATIONS OF A.I.D.S.

1Doctoral Student Family and Community Nursing Georgia State University Atlanta, Georgia 2Staff Nurse Neurosurgery Intensive Care Unit Grady Memorial Hospital Atlanta, Georgia 3Clinical Instructor University of North Carolina School of Nursing Chapel Hill, North Carolina

Clinical outcome of nosocomial pneumonia following imipenem/cilastatin therapy.

Eighteen patients in a neurosurgery intensive care unit who had nosocomial pneumonia and/or bacteremia were treated with imipenem/cilastatin. The 16 patients who were evaluable had pneumonia; 4 of these had concurrent bacteremia. Eleven patients had a satisfactory clinical response (69 percent) and all patients with positive blood cultures had the organism eradicated. There were 44 organisms isolated from the initial culture of bronchial secretion and 32 of these organisms were gram-negative bacilli (72.5 percent). One patient with pneumonia who initially had Pseudomonas aeruginosa sensitive to imipenem developed resistance during therapy. Adverse effects were minimal; one case of nausea occurred, which was thought to be related to a short infusion time. The most prominent laboratory abnormality was an increase in platelet count, seen in 50 percent of treated patients.