A Guide to Intensive Care Unit (3)

ICU指南(3)

The Equipment

设 备

The vast array of technology present in an average patient's room can be overwhelming. Even the beds have become incredibly complex, costing tens of thousands of dollars and requiring detailed operating instructions. It is stressful enough just to be in the room of a patient who is critically ill, let alone to cope with the anxiety that the equipment might alarm or malfunction and require an intervention. In reality, the machines in the ICU have many fail-safe backup systems so that mechanical failure is rare. Furthermore, devices that require more supervision are usually accompanied by an individual with expertise, such as a cardiac technician for an intra-aortic balloon pump or a hemodialysis technician for a hemodialysis machine. Respiratory therapists are in close proximity to patients' rooms and intervene quickly if a mechanical ventilator alarms or malfunctions. The best way to resolve anxiety is to become familiar with all of the different devices.

普通病人病房里的技术多得使人晕头转向，连床铺也复杂得令人难以置信，不但要花数万美元，还要有详细的操作说明。危重病人病房护理已够紧张的了，更不用说还要应付器械告警或故障需要处理这样令人焦虑的事。在现实中，ICU机 器都有很多故障保险备份系统，因此，出现机械故障的可能性很小。而且，需要监督的装置通常都由专业人员看着，如由心脏科技师负责主动脉内气囊泵或血透技师 负责血液透析机等。呼吸治疗师离病人房间很近，一旦机械呼吸机告警或故障，他可以很快进行处理。减轻焦虑的最佳方法是熟悉各种装置。

Bedside monitors

床边监测仪

All patients are connected to a bedside monitor whose screen displays several parameters. Channels I and II typically display two EKG leads providing continuous monitoring of the patient's heart rhythm. The patient's blood pressure is displayed either continuously from a catheter in the patient's arterial system or intermittently from an automatically inflating blood pressure cuff on channel III. The arterial line allows beat-to-beat measurement of blood pressure. An A-line is also inserted in patients who require numerous arterial blood gases in order to avoid repeated punctures.

所有病人都接有一个床边监测仪，它可以显示多种参数。其中通道I、II 主要显示两台EKG 导联仪，对病人心律进行连续监测。病人血压监测有连续和间断两种，前者通过病人动脉系统插管监测，后者通过通道III自动充气血压袖带监测。动脉插管可以测量每一搏动的血压情况，它可以用于需要大量动脉血气的病人，避免重复穿刺。

Patients may have a central venous catheter placed in the superior vena cava through the internal jugular or subclavian vein. A central venous catheter allows measurement of central venous pressure (CVP). The CVP serves as an estimate of the patient's volume status. Central lines are also used to rapidly infuse fluid and to administer substances that cannot be infused into a peripheral vein such as hypertonic parenteral fluids and medications such as vasopressors.

病人也可以经由颈内静脉或锁骨下静脉放置上腔静脉中心静脉插管，测定中心静脉压(CVP)，由此估计病人的容积状态。中心静脉插管也可用于快速输液和给药。一些周围静脉难以输入的药物或液体，如高渗非肠道液体、血管升压类药物等，都可以通过该插管输入。

When more data about a patient's hemodynamic physiology is required, a pulmonary artery catheter can be inserted and advanced through the right ventricle into the pulmonary artery. The PAC allows continuous display of pulmonary artery pressure, and variables such as cardiac output and pulmonary artery occlusion pressure, or wedge pressure, can be intermittently obtained. The "wedge pressure" is a measurement that reflects the patient's preload. The catheter is used to diagnose and manage hemodynamic instability. 医学全在线www.med126.com

如需要更多的病人血液动力生理学资料，就可以施行肺动脉插管(PAC)，经由右室插入肺动脉。PAC可以连续显示肺动脉压及其他多种变量，如心排血量，也可以间断性显示肺动脉闭塞压或楔压。楔压反映了病人的前负荷情况，插管用于诊断和处理血液动力学的不稳定性。

The respiratory rate and the pulse oximeter reading, which indicates the patient's oxygen saturation, are also displayed on the monitor. The pulse oximeter is a noninvasive monitor attached to the patient's finger or earlobe to measure oxygen saturation continuously. Bedside monitors can be set to alarm for bradycardia or tachycardia, hypotension or hypertension, tachypnea, and/or oxygen desaturation.

监测仪还可显示呼吸频率和脉氧值。脉氧仪显示病人氧饱和度，这是一种非侵入式监测仪，套在病人指头或耳垂上连续监测氧饱和度。经过设置，床边监测仪可以警示下列情况：心动过缓或过速，低或高血压、呼吸急促和/或氧减饱和。

Mechanical ventilators

机械呼吸机

Patients are mechanically ventilated for several reasons. If they are unable to protect their airway due to encephalopathy or massive stroke, they may be intubated (have an endotracheal tube placed through their mouth or nose into the trachea) to minimize the possibility of aspiration. If they have refractory hypoxemia (low oxygen saturation that does not respond to oxygen delivered by face mask), the ventilator will allow higher concentrations of FIO2 to be delivered to the alveoli, and pressure can be delivered through the ventilator to open alveoli that have collapsed. If they have respiratory failure and are unable to take adequate tidal volume, the ventilator can deliver a preselected tidal volume and respiratory rate. Patients remain on the ventilator until the underlying disease is resolved. When this occurs, the doctors and respiratory therapists begin the process of decreasing, or "weaning," ventilator support until the endotracheal tube can be removed, a process known as extubation.

病人因多种原因需要进行机械通气。如果病人因脑病或大面积中风无法保护气道，这时就需要插管(即经口或鼻施行气管内插管)，最大限度地减少抽吸可能性。如果病人有难治性低氧血症(低氧饱和度，面罩供氧无效)，呼吸机就可以将高浓度的吸入氧输送到肺泡，并通过呼吸机输送的压力张开塌陷的肺泡。如果病人呼吸衰竭潮气量不足，呼吸机就可以按预先设置的潮气量和呼吸率进行输送。在疾病消失前，病人都要使用呼吸机。如要除去呼吸机，医生和呼吸治疗师通常要先逐渐减少或“断奶”呼吸机支持，最后才拨掉气管内插管，即拨管。

Other common devices

其他

Intravenous medication pumps allow the nursing staff to titrate medications; Foley catheters and urine collection bags aid in monitoring urine output; sequential compression devices squeeze the lower extremities and reduce the incidence of deep venous thrombosis; transvenous pacemakers stimulate the patient's heart to beat; dialysis machines remove fluid and correct electrolyte and acid-base disturbances; intraaortic balloon pumps assist the heart's contractility; and neurologic monitoring systems measure intracranial pressure.

静脉内给药泵由普通护士用于滴定药物；弗利氏导管和集尿袋帮助监测排尿量；连续压迫装置挤压下肢，减少深部静脉血栓形成；经静脉起搏器刺激病人心脏跳动；透析仪除去液体，纠正电解质和酸碱紊乱；主动脉内气囊泵支持心脏收缩；神经病学监测系统测定颅内压。