Neurologic monitoring

This article discusses the current methods for monitoring the intracranial environment in the critical care setting. Intracranial pressure monitoring is discussed first. Then the electroencephalogram and sensory evoked potentials are considered. Finally, new techniques being evaluated are discussed.     

Neurologic intensive care unit monitoring

Monitoring modalities unique to the neurologic intensive care unit include intracranial pressure monitors and neuroelectrophysiologic monitors. Each modality fullfills criteria for accuracy, responsivity during clinical change, and stability over time for trend analysis. Intracranial pressure monitoring may be accomplished by any of three approaches--ventricular catheter, subarachnoid bolt, or epidural pressure transducer. Intracranial pressure control has proved beneficial in at least three different illnesses--acute closed head injury, acute noncommunicating hydrocephalus, and Reye's syndrome. Other illnesses, such as cerebral hemorrhage, near drowning, meningitis, encephalitis, and cerebral mass lesions, are often associated with ICP elevations. Neuroelectrophysiologic monitoring encompassing electroencephalography (EEG), signal-processed EEG, and evoked potentials has proved to be most beneficial to the intensive care setting. Evoked potentials are most useful for monitoring patients in drug-induced coma or muscle paralysis in whom a clinical neurologic examination is unreliable. Focal neurologic deficits, incipient brainstem ischemia, and possibly brain death can be deduced from multimodality-evoked potentials (brainstem auditory and somatosensory). Evoked potential apparatus can be used to record sequential stimuli and trend changes. Signal-processed EEG apparatus (compressed spectral array and cerebral function monitor) are used to assess global or regional EEG activity for longer periods of time. Interpretation of signal-processed EEG recording requires some experience with this technique, but it is much easier to interpret than a standard 16-lead EEG. These monitors are useful in evaluating some forms of abnormal EEG activity and in monitoring gross changes in global or regional electrical activity. Currently available technology offers dynamic insight into the management of acute neurologic illnesses. The technology in evoked potential and signal processed EEG monitoring will eventually reduce the size and complexity of the instrumentation, making its application routine. Intracranial pressure monitoring is already routine in many intensive care units, although its use is occasionally sporadic. We believe that application of appropriate neurologic monitors improves therapy and outcome in neurologically injured and ill patients.     

Proximal airway pressure monitoring in the neonatal ICU

The static and dynamic responses of diaphragm-type pressure manometers currently used with manual ventilation in the neonatal ICU were determined at different pressures and frequencies. Using a precalibrated transducer attached to a closed-loop system, the manometer peak pressure was adjusted to 15, 20, 25, and 30 cm H2O, first for static measurements and then again while the frequency was increased from 20 to 200 breath/min in increments of 20. Most manometers with inlet flow-restricting devices built into the manometer or attached to the connection system in a ventilator significantly underestimated the delivered pressure as the peak inflation pressure and frequency were increased. In those manometers without inlet flow restrictors the correlation between transducer pressure and observed manometer pressure was close. Diaphragm-type pressure manometers with inlet flow-restricting devices may substantially underestimate the delivered proximal airway pressure when incorporated into neonatal manual ventilation equipment.     

ICU monitoring of ventilation distribution

Summary The oxygen washin method has been shown to be a practical way to measure functional residual capacity (FRC) in the intensive care unit. The ventilator oxygen concentration is increased and measurements of respiratory flow and oxygen concentration at the mouth are made with the patient monitoring system. No additional personnel, bedside equipment or ventilator attachments are required. A feasibility study was performed to determine if this method could be used to estimate a continuous distribution of ventilation with respect to ventilation to volume ratio . Due to gas mixing in the ventilator, the inspired oxygen fraction does not increase instantaneously to its new value. An equation was derived which models the lung as 50 discrete compartments and accounts for the transient change in mean inspired oxygen fraction. A digital computer simulation demonstrated good distribution recovery for one and two mode ventilation distributions. Continuous distributions were computed for four post cardiac surgery patients at four levels of positive end expiratory pressure (PEEP). In these patients a linear increase in the amount of ventilation in the normal range occurred with increasing PEEP, i.e., slow and fast spaces tended to move centrally toward a more normal range. At zero PEEP 26% of the ventilation occurred in the normal range and this increased to 49% at 15 PEEP. Dead space fraction was poorly estimated and spurious modes occurred in the high range.     

Role of the bispectral index in sedation monitoring in the ICU

OBJECTIVE: To review and critique evidence for the use of the bispectral index (BIS) in intensive care unit (ICU) patients. DATA SOURCES: A computer search of English-language articles in MEDLINE (1966-July 2005), International Pharmaceutical Abstracts (1971-July 2005), and Scientific Citation Index Expanded (1980-July 2005) was conducted. A manual search of abstracts was also performed using the key search terms BIS, sedation, and critical care. STUDY SELECTION AND DATA EXTRACTION: Case series, letters, editorials, and clinical studies that evaluated BIS in ICU patients were considered for inclusion. DATA SYNTHESIS: Nineteen studies comparing the BIS with sedation scales were evaluated, revealing that the BIS trends lower with increasing sedation. The BIS appeared to correlate better when sedation scores were grouped rather than individual values. However, correlations between BIS and subjective scales were low in most studies (r(2) 0.21-0.93). Additionally, there was poor correlation between drug dosage and the BIS. Randomized, controlled trials demonstrating improved outcomes with BIS monitoring have not been reported. CONCLUSIONS: Interpreting literature on the usefulness of the BIS in the ICU is difficult for reasons that include heterogeneous populations, different methods of collecting BIS data, and use of different versions of BIS software and hardware. Outcomes data are lacking. The 2002 Society of Critical Care Medicine Sedation Guidelines recommendation that more data are needed before the BIS should be used routinely in the ICU remains unchanged. We recommend that further studies be conducted to determine the optimal method of obtaining BIS data and evaluate the impact of the BIS on relevant patient outcomes.     

ICU来源细菌耐药性监测

目的：了解我院重症监护病房（ICU）病原菌的分布特点及耐药性,为临床抗感染治疗提供理论依据。方法：采用纸片法、MIC法进行抗菌药物敏感性试验,使用WHONET5.6软件对我院2009年1月1日至2013年4月15日ICU来源的患者首次分离菌株进行分析。结果：共检出374株病原菌,其中革兰阴性杆菌67.4%,革兰氏阳性杆菌32.6%,前3位分别为鲍曼不动杆菌104株（27.8%）、铜绿假单胞菌48株（12.8%）、金黄色葡萄球菌40株（10.7%）;耐甲氧西林西林金黄色葡萄球菌和凝固酶阴性葡萄球菌的检出率分别为72.5%和52.7%,未发现耐万古霉素和耐利奈唑胺葡萄球菌;未见对万古霉素耐药的粪肠球菌和屎肠球菌;产ESBLs大肠埃希菌和肺炎克雷伯菌的比率分别为61.5％和72.2％;鲍曼不动杆菌对碳青霉烯类抗菌药物的耐药率达57.6％,检出泛耐药鲍曼不动杆菌30株。结论：ICU分离菌株对常用抗菌药物的耐药率较高,应采取积极措施加以控制。     

Nutritional monitoring in the ICU: rational and practical application

The metabolic response to injury can induce a state of hypermetabolism that results in the rapid loss of the body nitrogen, so that a critical reduction in lean body mass that affects morbidity and mortality can occur in a short period of time. The process also induces a redistribution of the body nitrogen away from the skeletal mass and toward the viscera and areas of increased metabolic activity, such as the surgical wound, the zone of inflammation, and toward cells producing mediators. Exogenously administered nitrogen is not very effective in reducing the rate of catabolism. It can, however, increase the rate of protein synthesis. In so doing, the rate of net catabolism is reduced. The modified amino acids appear to be much more effective in achieving these ends than do the standard amino acid formulas. Visceral protein synthesis is difficult to use as an index of visceral protein malnutrition in the settings where the metabolic response to injury is also present. These proteins and the acute-phase reactants may not have the sensitivity and specificity to discriminate between visceral protein malnutrition and the changes induced by the metabolic response to injury. The practical clinical endpoint, then, in managing the nitrogen economy during the metabolic response to injury is to provide adequate nitrogen intake, achieving 2 to 4 gm of positive nitrogen balance whenever possible. Caloric (energy) equilibrium can be achieved. Calories in excess of demand or glucose in excess of the ability to effectively oxidize, however, can have detrimental effects in some settings. Expired gas analysis can be useful in this context. Achieving caloric equilibrium does not appear to be essential. The reduction in malnutrition as a cofactor in morbidity and mortality appears to come from achieving nitrogen equilibrium. These alterations in metabolism induced by metabolic stress and the changes in nutrient requirements have been called metabolic support and are summarized in Table 3. The end-points of metabolic support, whenever possible, become 2 to 4 gm of positive nitrogen balance with an amino acid load that will achieve that balance; support of visceral protein synthesis as judged by acute-phase reactant and hepatic protein (e.g., transferrin) synthesis; and avoiding complications of excess VCO2 and urea production (BUN less than 110 mg per cent) (Fig. 5).     

护理质量监控记录本在ICU的应用

目的探讨护理质量监控本在ICU的应用与效果。方法设立ICU质量监控记录本,成立质量控制管理组,选择监控组长,规范质量监控记录本的书写格式、内容及跟踪记录方法。结果应用护理质量监控本后,护理部检查护理综合质量合格率从94．54％上升至97．41％,差异具有统计学意义（X2=7．788,P〈0．01）;护士长自查护理综合质量合格率从93．59％上升至96．15％,差异具有统计学意义（x2=5．270,P〈0．05）;护理不良事件发生率从2．5％降至0．8％,差异具有统计学意义（x2=5．722,P〈0．05）。结论护理质量监控记录本的应用完善了质量反馈体系,提高了管理效率,有利于提高护理综合质量,减少护理不良事件的发生。     

电子体温监测探头在危重患者体温监测的意义

目的:选择准确、方便的测量方法,提高危重患者体温测量的准确性。方法:分别选择汞柱式腋温计与电子体温监测探头,对ICU内GCS评分3～7分的60例患者进行体温测量,比较其差异性。结果:电子体温监测探头与汞柱式腋温计测量结果比较差异无显著性(P>0.05)。结论:使用电子体温监测头对危重患者进行体温监测具有实时、方便,减少因患者不能保持最佳的测量姿势造成的重复测量及测量误差,减少护理工作量等特点,该方法安全可靠,并适合与其它监护设备一起使用,实现对患者基本生命体征的实时监护。     

双频指数监测在重症监护病房的应用

[目的]探讨双频指数（BIS）与镇静程度的关系。[方法]对重症监护病房（ICU）56例病人应用双频指数监测镇静情况进行观察。[结果]BIS值与Brussels镇静评分有较好的相关性（R^2=0.9947）。[结论]通过观察ICU病人BIS，可估计病人的镇静程度.     

PiCCO监测技术在ICU的临床应用与护理

脉搏指示连续心排血量(PiCCO)监测是一种比较新的微创血流动力学监测技术,其创伤小、并发症少,在连续监测心排血量、血管外肺水含量等方面有较好的临床应用价值和前景^[1] 。本文通过对2014年6~12月收治的9例危重症患者实施PiCCO监测,寻找最佳的护理方法,包括置管的配合、监测的要点、置管的维护及管理等,以达到此技术在ICU护理领域的进一步提高与完善。     

Neurologic prognostication and bispectral index monitoring after resuscitation from cardiac arrest

Objective

While the use of therapeutic hypothermia (TH) has improved outcomes after resuscitation from cardiac arrest, prognostication of survival and neurologic function remains difficult during the post-arrest time period. Bispectral index (BIS) monitoring, a non-invasive measurement of simplified electroencephalographic data, is increasingly being considered for post-arrest neurologic assessment and outcomes prediction, although data supporting the technique are limited. We hypothesized that BIS values within 24 h after resuscitation would correlate with neurologic outcomes at discharge.

Methods

We prospectively collected BIS data in consecutive patients initially resuscitated from cardiac arrest and treated with TH in one academic medical center. We assessed BIS values in context of cerebral performance category (CPC) assessment on the day of discharge.

Results

Data were collected in 62 post-arrest patients, of whom 26/62 (42%) survived to hospital discharge. Mean BIS values at 24 h post-resuscitation were significantly different in the survivors with CPC 1-2 (“good” outcome) vs those with CPC 3-5 (“poor” outcome) or death during hospitalization (49 ± 13 vs 30 ± 20; p < 0.001). Receiver operator characteristic analysis suggested that 24 h BIS was most predictive of CPC 1-2 outcome compared to the other timepoints; a BIS cutpoint of 45 exhibited a sensitivity of 63% and a specificity of 86%, with a positive likelihood ratio of 4.67. Sixteen patients exhibited a BIS of zero during at least one timepoint; all of these patients died during hospitalization.

Conclusions

BIS monitoring values at 24 h post-resuscitation are correlated with neurologic outcomes in patients undergoing TH treatment. In 16/62 patients, a BIS of zero at any timepoint was observed, which was uniformly correlated with poor outcome after resuscitation from cardiac arrest; however, a non-zero BIS is insufficient as a sole predictor of good neurologic survival.     

Clinical review: Respiratory monitoring in the ICU - a consensus of 16

ABSTRACT: Monitoring plays an important role in the current management of patients with acute respiratory failure but sometimes lacks definition regarding which 'signals' and 'derived variables' should be prioritized as well as specifics related to timing (continuous versus intermittent) and modality (static versus dynamic). Many new techniques of respiratory monitoring have been made available for clinical use recently, but their place is not always well defined. Appropriate use of available monitoring techniques and correct interpretation of the data provided can help improve our understanding of the disease processes involved and the effects of clinical interventions. In this consensus paper, we provide an overview of the important parameters that can and should be monitored in the critically ill patient with respiratory failure and discuss how the data provided can impact on clinical management.     

Transcutaneous PCO2 monitoring on adult patients in the ICU and the operating room

Studies were performed on 44 patients who were monitored continuously with transcutaneous carbon dioxide (PtcCO2) sensors. The patients were monitored intermittently with arterial and mixed venous blood gases and full hemodynamic and oxygen transport data. Twenty of the studies were performed intraoperatively. A total of 411 data sets revealed a correlation coefficient, r, between arterial and transcutaneous PCO2 of 0.80 when the patients were not in low flow shock, i.e., cardiac index (CI) greater than 1.5 L/min x M2. On the basis of these data, the authors have found the normal arterial-transcutaneous carbon dioxide gradient, delta CO2, (delta CO2 = PtcCO2 -- PaCO2) to be 23 +/- 11 torr. The PtcCO2 monitor was found to be a valuable trend monitor of arterial CO2 tensions of adults during adequate cardiac function in the ICU and the operating room. Twenty-four data sets were collected while 3 patients were monitored during severe shock (CI less than 1.5 L/min x M2). PtcCO2 trended inversely with changes in CI during shock and did not follow PaCO2 (r = --0.85). During shock, delta CO2 = 61 %/- 25 torr. The severity of shock could be roughly determined by comparing the PtcCO2 values with arterial CO2 tensions.     

ICU重型颅脑损伤患者的有效监护

笔者报道ICU重型颅脑损伤患者的有效监测及护理。内容包括神经功能监护、生命体征监护、持续颅内压监护、中心静脉压监护、脑电图监护及电解质、血和尿渗透压、肝肾功能的检查,采用格拉斯哥评分标准对患者进行正确评分,及时掌握患者的病情进展情况,进行特殊护理。有效地促进了患者的康复,减少了并发症的发生。     

综合ICU监护岗岗位描述的研究

[目的]明确综合ICU监护岗的任职资格和工作内容。[方法]在现场调研的基础上,查阅大量文献,结合预调查,拟定专家咨询问卷,应用Delphi法向全国32位专家进行两轮咨询。[结果]综合ICU监护岗岗位描述有主要工作职责(包括工作目的、具体工作内容)和任职资格(包括年龄、学历、技术职称、相关工作经验、岗前培训时间、证书要求、知识要求、专科护理技术要求、能力要求)。[结论]任职资格和岗位描述的确立,为该岗位在临床的规范化设置提供理论依据。