特殊药物监测单在临床中的应用

不同病种、不同患者所用药品种类不同,每一种药物都有其不同的观察重点。在心内科硝普钠(SNP)应用较为广泛,其化学性质不稳定,对光敏感,易失效;降压迅速易发生低血压,因此,做好护理监测十分重要。为了保证监测的及时性、可靠性,确保医疗安全,同时也为了适应新《医疗事故处理条例》的实施,举证倒置,我们设计应用了“特殊药物监测单”,现报道如下。资料与方法1.一般资料。2004年1月-2005年1月,我科应用硝普钠治疗心衰患者45例,年龄34~82岁,平均年龄61.5岁。冠心病21例,肺原性心脏病6例,高血压性心脏病14例,风湿性心脏病4例。2.使用方法。45…     

Transcutaneous and liver surface PO2 during hemorrhagic hypotension and treatment with phenylephrine

Transcutaneous PO2 (PtcO2) and liver surface PO2 (PIO2) were measured in six mongrel dogs during hemorrhagic shock, normotensive shock, and volume resuscitation. Normotension was produced during extreme hypovolemia by an infusion of phenylephrine. PtcO2 and PlO2 were compared to each other and to hemodynamic and oxygen transport variables. PtcO2 and PlO2 correlated well with cardiac index (CI) r = .71 and .86, respectively; n = 60) and with each other (r = .79; n = 60). Heart rate, mean arterial pressure (MAP), and PaO2) correlated less with PtcO2 or PlO2. During the normotensive shock period, PtcO2, PIO2, CI, oxygen delivery (DO2), and oxygen consumption (VO2) were all severely decreased, while PaO2 and MAP were normal and lactic acid concentrations were elevated. It was concluded that PtcO2 follows changes in PlO2 during hypotensive and normotensive low cardiac output shock in mongrel dogs. Low PtcO2 values are associated with low values of PlO2, DO2, VO2, and rising lactic acid concentrations in dogs. These animal data imply that low PtcO2 values encountered in clinical monitoring during anesthesia and surgery may correspond to decreased blood volume, blood flow, and PlO2.     

Transcutaneous monitoring during high-frequency jet ventilation

Simultaneous transcutaneous PO2 (PtcO2) and PCO2 (PtcCO2) recordings, done on a patient during high-frequency jet ventilation (HFJV) in thoracic surgery, reflected exactly PaO2 and PaCO2 changes induced by surgical manipulation and by ventilator setting alterations. PtcO2 and PtcCO2 monitoring with a single sensor was valuable during HFJV for the early detection of acute changes in the efficacy of gas exchange and for the correction of the ventilator setting.     

Is transcutaneous PO2 monitoring during exercise a reliable alternative to arterial PO2 measurements?

Summary. Arterial PO₂ measurement during exercise is an important part in the evaluation of pulmonary disease but requires an intra-arterial cannula. However, in clinical work it would be preferable to assess PO₂ non-invasively. To evaluate such a technique, simultaneous measurements of transcutaneous PO₂ (tcPO₂) and arterial PO₂ (PaO₂), sampled from an indwelling arterial radial cannula, were made before, during and after a fatigue or symptom-limited bicycle exercise test in 16 patients referred to hospital because of dyspnoea. In total 181 paired measurements were made. Mean values (range) of PaO₂ and tcPO₂ were 11-2 kPa (5–16) and 9-5 (5–13-3), respectively. The correlation coefficient between PaO₂ and TcPO₂ was only 0–36 (P < 10^-5). By normalizing the values of tcPO₂ and PaO₂ to corresponding values at supine rest before exercise, the correlation coefficient increased to 0–80 (P < 10^-6). Using PaO₂ as golden standard, tcPO₂ described the trend in pO₂ during exercise reasonably well in all cases and this information is often sufficient for assessing the degree of pulmonary insufficiency. Thus, transcutaneous blood gas monitoring during exercise is useful for clinical evaluation of pulmonary disease, but a single arterial blood sample at rest before exercise is recommended for baseline correlation.,     

Transcutaneous carbon dioxide monitoring during neonatal transport

We studied the value of transcutaneous carbon dioxide (PtcCO2) monitoring during neonatal transport. Thirty-two neonates with respiratory distress were alternately enrolled in an experimental group (results of PtcO2 and PtcCO2 available for clinical management) and a control group (results of only PtcO2 available). Although differences were not significant, infants in the experimental group had more changes in the intermittent mandatory ventilation (IMV) settings during transport, and more such infants arrived at the receiving hospital with acceptable pH and PCO2 values. On arrival at the receiving hospital, two patients in the control group had acidosis and hypercarbia and were placed on IMV immediately on arrival. No such patients were encountered in the experimental group. For patients needing IMV during transport, the percentage of study time spent with PtcCO2 measurements in the normal range (35 to 45 torr) was greater for the experimental group (p less than .02). Continuous PtcCO2 monitoring during transport offers the opportunity to further decrease the risks of transporting a critically ill neonate.     

Non-invasive conjunctival PCO2 and PO2 monitoring during hyper- and hypoventilation

In order to evaluate potential applications of non-invasive fiberoptic conjunctival carbon dioxide (Pcj,CO2) and polarographic oxygen (Pcj,O2) sensors, we studied the effects of graded hyper- and hypoventilation on Pcj,CO2 and Pcj,O2 values in dogs. Pcj,CO2 values correlated well with Pa,CO2 (r = 0.95, n = 114); the mean Pcj,CO2--Pa,CO2 gradient was 4 +/- 3 (S.D.) Torr. Both hyper- and hypoventilation resulted in decreased Pcj,O2 values, whereas decreased Pa,O2 was observed only during hypoventilation; thus, the Pcj,O2/Pa,O2 index decreased during hyperventilation but was maintained during hypoventilation. Because both cerebral and conjunctival capillary beds vasoconstrict during hyperventilation, this methodology may assist in the non-invasive monitoring of cerebral oxygenation during cerebral resuscitation and surgery. Non-invasive Pcj,CO2 monitoring, which reflects Pa,CO2 during changes in ventilation, may be used to simplify ventilator management and weaning, as well as guide appropriate timing of arterial blood gas analysis in hemodynamically stable patients.     

Enhanced renal production of cyclic GMP and reduced free water clearance during sodium nitroprusside infusion in healthy man

Abstract. A 90–min intravenous infusion of the direct vasodilator sodium nitroprusside (SNP) was compared with a placebo infusion in 32 healthy control subjects in order to study the acute effects of SNP on renal haemodynamics, tubular function evaluated by the lithium clearance technique, the plasma levels of atrial natriuretic peptide (ANP), angiotensin II (Ang II), aldosterone (Aldo) and arginine vasopressin (AVP) and the tubular transport of cGMP (T_cGMP). SNP infusion induced a significant reduction in mean arterial blood pressure (from 89.5 to 81.5 mmHg), urinary output (from 7.7 to 4.5 ml min^-1), free water clearance (from 4.0 to 1.3 ml min-^I) and ANP (from 3.3 to 2.5 pmoll-¹) and a significant increase in heart rate (from 57 to 64 beats min^-l), Ang II (from 11 to 18 pmoll^-1), Aldo (from 189 to 308 pmol L^-1) and in the tubular secretion of cGMP (T_cgmP from 28.8 to 214.4 pmol min^-1), (all values are medians and changes from baseline to 90 min after infusion start). Glomerular filtration rate, renal plasma flow, urinary sodium excretion, lithium clearance and plasma level of AVP were not significantly changed. It is concluded that SNP infusion in healthy subjects decreases urinary output and free water clearance without any change in sodium excretion, indicating a dissociation between the salt and water retaining effects of SNP in the early phase of treatment, probably due to an enhanced distal tubular water reabsorption of water. It is suggested that this increase in reabsorption of water in the distal parts of the nephron during SNP infusion may be mediated by an increase of cGMP production in the kidney, as indicated by the increase in T_cGMP during the SNP infusion.     

Transcutaneous O2 and CO2 monitoring of high risk surgical patients during the perioperative period

The usefulness of noninvasive transcutaneous oxygen (PtcO2) and carbon dioxide (PtcCO2) sensors as well as invasive monitoring of flow and oxygen transport were evaluated in the perioperative period of a small series of high risk surgical patients. We used the pattern of physiological events preceding intraoperative death as the criteria for evaluation of the relative usefulness of these variables. Cardiac output (CO), oxygen delivery (DO2), and O2 consumption (VO2) provided the earliest warning of impending circulatory deterioration and were most useful during critical nonlethal circulatory episodes; these were closely paralleled by the PtcO2 index (PtcO2/PaO2); the PtcCO2 was less sensitive. Heart rate (HR) and mean arterial pressure (MAP) were highly variable with frequent changes unrelated to change in flow and O2 transport.     

ST changes during sodium nitroprusside therapy in acute myocardial infarction

Nineteen patients with acute anterior myocardial infarction who were hypertensive (systolic BP greater than or equal to 170 mm Hg and/or diastolic BP greater than or equal to 100 mm Hg) at the time of admission were treated with continuous infusion of sodium nitroprusside (NP). The administration of NP resulted in a significant elevation of ST segments probably related to decreased diastolic BP and increased HR; direct NP effects on coronary circulation cannot be excluded. These changes may indicate a negative effect on the ischemic portion(s) of the myocardium.     

Transcutaneous respiratory electromyographic monitoring

The integrated diaphragm electromyogram (EMG) signal reflects function from the inspiratory centers to the neuromuscular junction. The feasibility and potential value of transcutaneous diaphragm electromyography (tcEMG) was confirmed in a group of infants using two prototype respiratory EMG monitors. Infants were monitored continuously for periods ranging from hours to days. One hundred were monitored for clinical reasons, looking for disordered respiratory behavior, while 47 were studied for technical/experimental reasons. Reliable measurements of diaphragm EMG activity were obtained, provided fully shielded electrode cables were used. Measurements in 28 ventilated infants and one adult confirmed that, unlike impedance and other non-electrophysiologic measures, tcEMG monitoring is not contaminated by ventilator-induced respiratory movements. The potential value of tcEMG monitoring in ventilated subjects is exemplified by illustrations of: diaphragmatic inactivity from phrenic nerve injury, inadequate central drive, and neuromuscular block; augmented expiratory muscle activity; and progressive increase in inspiratory diaphragmatic activity in the presence of a tension pneumothorax. TcEMG monitoring should prove a worthwhile addition to the available noninvasive respiratory monitoring techniques.     

Transcutaneous carbon dioxide monitoring

Technologies now exist that measure carbon dioxide levels transcutaneously. Rapid assessment of patients who have depressed ventilation or suspected sepsis can improve treatment decisions including the need for admission to the ICU and pulmonary artery catheterization.     

Transcutaneous carbon dioxide monitoring during high-frequency oscillatory ventilation in infants and children

OBJECTIVE: Continuous monitoring of ventilation during mechanical ventilation may improve patient management by facilitating proactive rather than reactive ventilator adjustments and may decrease the need for repeated arterial blood gas analysis. Because of their more critical pulmonary status, patients requiring high-frequency oscillatory ventilation may especially benefit from continuous monitoring. DESIGN: Prospective evaluation of the correlation between transcutaneous CO2 (TC(CO2)) and PaCO2 values. SETTING: Tertiary care pediatric intensive care unit. PATIENTS: Fourteen pediatric patients receiving high-frequency oscillatory ventilation for severe respiratory failure. INTERVENTIONS: TC(CO2) was monitored continuously and compared with PaCO2 values when arterial blood gas analysis was performed. MEASUREMENTS AND MAIN RESULTS: One hundred sample sets were obtained from 14 patients age 1 day to 16 yrs (3.5 +/- 4.6 yrs) and weighing 3.1-85 kg (18.5 +/- 22.4 kg). The mean absolute difference between PaCO2 and TC(CO2) was 2.8 +/- 1.9 mm Hg. Regression analysis of TC(CO2) and PaCO2 values revealed a slope of 1.04, an r value of.96, and an r value of.94 (p <.0001). Bland-Altman analysis revealed a bias of 2.1 mm Hg with a precision of 2.7 mm Hg when TC(CO2) was compared with PaCO2 for the entire group. In the subgroup where PaCO2 was 50 mm Hg, the bias was 2.3 with a precision of 2.6 (p = not significant). CONCLUSIONS: TC(CO2) monitoring provides an accurate and clinically acceptable estimate of PaCO2 over a wide range of CO2 values in pediatric patients during high-frequency oscillatory ventilation.     

Elevated carboxyhemoglobin associated with sodium nitroprusside treatment

Objective To report four cases of carboxyhemoglobinemia associated with high doses of sodium nitroprusside after cardiac transplant in children.Patients Four children in the pediatric care unit of a university hospital aged 6 months–4 years.Carboxyhemoglonemia developed at levels of 5.5–7.7% in patients receiving high doses of sodium nitroprusside (7–16 µg/kg per minute and no other medication that could caused elevated carboxyhemoglobin). One patient died, and three recovered with no sequelae after discontinuation of sodium nitroprusside.Conclusions High doses of sodium nitroprusside can induce carboxyhemoglobinemia in children after heart transplant, probably by inducing hemeoxygenase, with no other secondary effects.