[Economics in intensive care medicine: rationalization or rationing?]. / Okonomie in der Intensivmedizin: Rationalisieren oder Rationieren?

Four thesis related to economics of intensive care medicine are derived from an analysis of the intensive care unit of the university hospital of Basel, Switzerland, and the respective literature: (1) Intensive care medicine is costly but rationing can be avoided by rationalization. (2) Exemption or withdrawal of intensive care cannot be justified in the absence of accurate predictors of costs and outcomes of individual patients. (3) Intensive care physicians must not act as judges but on behalf of patients incapable of decision making. They must represent patients' interests vis-à-vis authorities and reimbursing institutions. (4) Analyses of cost-efficiency are instrumental for process improvement of intensive care, for negotiations on reimbursement and for the regulatory decisions of the authorities. Tools for economic analyses of intensive care medicine are therefore worthy of further development.

Renal vascular hyperresponsiveness to elevated ionized calcium in spontaneously hypertensive rat kidneys.

OBJECTIVES: Calcium may be indicated in critically ill patients for hemodynamic support. Its well-known action includes peripheral vasoconstriction. Vascular effects of calcium are unknown, however, in the presence of hypertension or in combination with calcium channel blocking drugs, commonly prescribed in the treatment of hypertension. The renal vessels of the spontaneously hypertensive rat (SHR) represent a suitable study model, because their vascular reactivity closely agrees with that in hypertensive humans. The present study should clarify (a) are the renal vessels of SHR responsive to high and low ionized calcium ([Ca+2] within the clinical ranges? (b) because release of nitric oxide is calcium ion dependent, are renal vascular responses altered after inhibition of NO synthase? (c) are vascular responses of SHR to hypercalcemia altered by the calcium channel blocking drug verapamil? ANIMALS AND INTERVENTIONS: We compared isolated kidneys of SHR and those of two strains of age-matched normotensive rats (NTR) in their responses to high and low [Ca+2]. They were perfused with oxygenated, warmed (37 degrees C) albumin containing Krebs-Henseleit buffer. In protocol A (n = 8 for each rat strain) steady state high [Ca+2] (1.88 mmol/l) and low [Ca+2] (0.55 mmol/l) were instituted in randomized order. In protocol B (n = 8 for each rat strain) interventions identical to those of protocol A were instituted after inhibition of NO synthase with NG monomethyl-L-arginine (L-NMMA). In protocol C, high and low [Ca+2] levels were instituted in SHR after verapamil pretreatment. At each [Ca+2] we measured changes in renal flow at constant perfusion pressures of 100 and 150 mm Hg. RESULTS: In SHR (perfusion pressure 100 mm Hg), high [Ca+2] induced a decrease in renal flow (-11.8 +/- 1.8% of control), which was significantly greater (p < 0.05) than the change (-6.1 +/- 1.5 and -6.9 +/- 1.4% of control) recorded in the two normotensive strains. In SHR (perfusion pressure 150 mmHg), high [Ca+2] induced a decrease in renal flow (-12 +/- 1.3% of control), also significantly greater (p < 0.05) than the changes (-6.2 +/- 1.1 and -5.8 +/- 1.7% of control) in the two normotensive strains. Similar differences and significances were again observed after L-NMMA pretreatment. In SHR, verapamil prevented renal vascular responses in SHR to both high and low [Ca+2]. CONCLUSIONS: First, renal vascular responses to high [Ca+2] in SHR are exaggerated. At the upper end of the hypercalcemia range the observed changes in renal flow at constant perfusion pressure were modest, however, and with lesser degrees of hypercalcemia they may be anticipated to be even less pronounced. Second, effects of high [Ca+2] were abolished after verapamil. If these findings are clinically applicable, they are of interest when calcium is infused in patients with hypertension.

Wellness for people 65 years and better.

Wellness is within the grasp of all persons, no matter what age. Gerontological nurses, in care partnerships with other disciplines and business and health organizations, still have numerous opportunities in their communities to contribute to the well-being of aged individuals. Only 68% of the sentinel objectives established by The Public Health Service in Healthy People 2000 have shown improvement (Peterson, 1996). There is still room for development of the Healthy People 2000 initiatives and various opportunities for gerontological nurses to assist elders on their journey to wellness.

Renovascular responses to high and low perfusate calcium steady-state experiments in the isolated perfused rat kidney with baseline vascular tone.

Acute hypercalcemia is commonly observed in surgical patients after calcium infusion while acute hypocalcemia is common during rapid citrated blood transfusion. Although high and low ionized calcium ([Ca2+]) within the clinical range produce an increase or decrease in cardiac performance and systemic vessel resistance, respectively, their effects on renal vessels have not been quantified. A possible renal vasoconstriction that might occur with high [Ca2+] is of clinical interest because it is a factor which may contribute to impaired renal circulation and decreased function. In this study we examined the renovascular responses to [Ca2+], which was varied within the clinical range under hemodynamically controlled conditions. We instituted high and low [Ca2+] in the per fusate, which consisted of Krebs-Henseleit buffer containing albumin, 60-65 g/liter. Stable high (n = 10) or low (n = 7) [Ca2+] (1.93 +/- 0.02 and 0.59 +/- 0.01 mM, respectively) was instituted for 10 min and preceded and followed by normal [Ca2+] of the same duration. In a separate protocol (n = 8) verapamil (10(-5) M) was added to the perfusate 10 min before high [Ca2+] was tested. We measured changes in renal flow at a constant perfusion pressure of 110 mm Hg and also characterized the renal vessels over a range of pressures by pressure vs flow plots. High [Ca2+] was associated with a small decrease in flow (from 28.8 +/- 2.4 to 26.9 +/- 2.6 ml/min/g, P < 0.02), indicating a small vasopressor effect. This effect was also shown by a leftward shift in the pressure vs flow plots. These changes were prevented by verapamil. GFR decreased (from 0.35 +/- 0.04 to 0.28 +/- 0.06 ml/min/ g, P < 0.01) without a significant change in sodium excretion or fractional sodium excretion. Low [Ca2+] was associated with increased renal flow (from 30.8 +/- 2.1 to 35.2 +/- 2.7 ml/min/g, P < 0.02), indicating a vasodilator effect. This effect was also shown by a rightward displacement of the pressure vs flow plots. GFR increased from 0.51 +/- 0.03 to 0.56 +/- 0.04 ml/min/ g, P < 0.01, as did sodium excretion (from 2.32 +/- 0.22 to 3.87 +/- 0.49 microEq/min, P < 0.01) and fractional sodium excretion (from 2.33 +/- 0.26 to 3.61 +/- 0.49%, P < 0.01). We conclude, first, that in the isolated perfused rat kidney, high [Ca2+] is a weak vasopressor while low [Ca2+] has vasodilator action. Second, high [Ca2+] effects are abolished by verapamil pretreatment. These findings illuminate mechanisms of high [Ca2+] effects on renovascular tone.

Oscillometric blood pressure measurements by different devices are not interchangeable.

Blood pressure (BP) is frequently measured in patients by noninvasive blood pressure (NIBP) monitors. Values obtained by oscillometric devices of different brands may appear in one patient's record as if they were interchangeable; their concordance, however, has not been established. In 25 patients with major depression who were treated with electroconvulsive therapy (ECT) BP was measured on either arm by devices manufactured by SpaceLabs (SpL, 12 patients, 182 data points) and Marquette (Marq, 13 patients, 193 data points), respectively, and comparisons were made with simultaneous measurements on the opposite arm by Dinamap 1846SX (DIN), during the awake state and at 1-min intervals up to 5-7 min after ECT. Because ECT is associated with an intense, but short-lasting hyperdynamic state, comparisons of BP values could be made over a wide range of pressures. Bland-Altman plots were constructed to show the distribution of pressure differences at all pressures. Agreements between two instruments were judged according to guide lines by the American Association for Advancement of Medical Instrumentation (AAMI). The standard deviation of the difference (SDD) between two DIN devices was 7 mm Hg for systolic (SBP) and 6.3 mm Hg for diastolic blood pressure (DBP), whereas mean differences were 0.9 and 0.2 mm Hg, respectively (P = not significant [NS]), thus showing reproducibility. Corresponding SDD values SpL versus DIN were 9.1 for SBP and 8.3 mm Hg for DBP, while the mean differences were 1.6 (P = 0.026) and 7.3 (P = 0.0001) mm Hg, respectively. Corresponding SDD values for Marq versus DIN were 11.8 and 9.7 mm Hg with mean differences of 0.8 (P = NS) and 0.3 (P = NS) mm Hg. Whereas SBP differences DIN versus DIN exceeded 10 mm Hg in only 10% of observations, they exceeded that threshold in 31% and 32% of observations for SpL versus DIN and Marq versus DIN, respectively. In view of the variability that exceeds the AAMI guidelines and the one out of three occurrence of individual SBP differences exceeding 10 mm Hg for comparisons of SpL or Marq versus DIN, measurements by these three oscillometric devices are not interchangeable.

Renal vascular responses to high and low ionized calcium: influence of norepinephrine in the isolated perfused rat kidney.

OBJECTIVE AND DESIGN: The aim of this study was to examine the influence of norepinephrine (NE) on renal vascular responses to high (1.88 mmol/L) and low (0.56 mmol/L) perfusate-ionized calcium ([Ca2+]) in the isolated perfused kidney of the rat. High and low [Ca2+] encompassed the clinical concentration range in this multiexperiment, randomized trial. MATERIALS AND METHODS: Rats (n = 25), ranging in age from 3 to 4 months, were anesthetized and the ureter and renal artery were cannulated. The right kidney was perfused with oxygenated, warmed albumin (67 g/L) containing Krebs-Henseleit buffer and placed in a thermostated chamber without interruption of flow. In protocol A (n = 7), steady-state high [Ca2+] (1.88 mmol/L) and low [Ca2+] (0.56 mmol/L) were instituted in randomized order in each experiment under basal conditions. In protocol B (n = 9), the same interventions were instituted during constant rate NE infusion. Changes in renal flow were measured at constant perfusion pressure (110 mm Hg), and renal vascular resistance (RVR) was calculated. Renal function was assessed by clearance of [14C]inulin and by fractional excretion of sodium. With NE-induced preconstriction, the increase in RVR observed during high [Ca2+] was +17.8 +/- 1.8% of control, and the decrease in RVR observed during low [Ca2+] was -35.9 +/- 8.2% of control. Both values were greater by a factor of 2 than corresponding results obtained under basal conditions (7 +/- 2.1% vs. -13.5 +/- 4.1% of control, respectively, p < 0.05). Whereas the decrease in glomerular filtration rate with high [Ca2+] was not significantly influenced by NE pretreatment (-9 +/- 1.8% of control with high [Ca2+] in combination with NE vs. 4.1 +/- 0.7% of control under basal conditions), the increase in glomerular filtration rate with low [Ca2+] was significantly greater in the presence of NE (12 +/- 0.7 vs. 102 +/- 8.5% of control, p < 0.01). CONCLUSIONS: Whereas under basal conditions renal vascular effects of high and low [Ca2+] (varied within the clinical concentration range) are small, the changes recorded with the same interventions after NE pretreatment are increased by a factor of > 2. Hypercalcemia-induced renovascular constriction and decreased function are unfavorable, especially in patients who are at risk for renal dysfunction from other causes.

Nitric oxide dose-response study in the isolated perfused rat kidney after inhibition of endothelium-derived relaxing factor synthesis: the role of serum albumin.

The dose-response relationship of steady-state nitric oxide (NO) administration on renal vascular resistance in isolated rat kidneys (IPRK) perfused at constant pressure was investigated after inhibition of NO synthesis with NG-monomethyl-L-arginine (L-NMMA). To study the influence of biological thiols on renovascular NO effects, experiments were carried out with Krebs-Henseleit (KH) perfusate solutions alone, and in combination with bovine serum albumin (KH-ALB). Steady-state administration of NO by gassing the perfusate with 0 to 340 ppm NO led to graded decreases in renovascular tone. The minimal effective NO perfusate concentration in the absence of endogenous NO synthesis was about 6 to 8 nM, whereas a near-maximal effect was observed with approximately 200 nM. The presence of albumin reduced the speed of onset of renal vasodilation and the maximal effect at a given concentration of NO. After termination of NO administration, NO-induced vasodilation persisted in KH-ALB perfused kidneys for 30 min, whereas KH-perfused kidneys showed a rapid reconstriction. These findings suggest that the prolonged, potent renal vasodilation was caused by a reaction of bovine serum albumin (BSA) with oxides of nitrogen to form S-nitroso-BSA. Nitrosothiol levels in the KH-ALB perfusate were found to be proportional to the concentration of NO administered. The above-mentioned findings, confirmed in identical experiments with diethylamine NONOate, a novel NO-liberating substance, support the biological importance of S-nitrosothiols (RS-NO) in the action and metabolism of endothelium-derived relaxing factor (EDRF) in the IPRK.

[Emergency therapy of burns]. / Akuttherapie von Verbrennungen.

Burns are among the most common accidental injuries, occurring in almost any environment to victims of all ages. Most of them are minor injuries and may be treated on an out-patient basis. Superficial (first-degree and superficial second-degree) burns will heal uneventfully in about two weeks without scarring, as long as no infection complicates the healing process. Major burns, however, are life-threatening, and professional treatment is crucial for survival. The intensive care and the surgical treatment in these patients demand a major commitment in terms of personnel and material resources; in addition, emotional reactions by any person involved in the case are not uncommon. A skilled and knowledgeable on-scene emergency treatment may diminish the depth of the burn wound and will furthermore reduce the number of complications like hypovolemic shock and infection. A complete clinical assessment including the patient history gives the rationale for any therapy and will help determine the appropriate referral center. The emergency treatment primarily includes the cooling of the burn wound to stop the burning process and to reduce pain, the insertion of an intravenous line, including the infusion of 1 to 2l of an isotonic electrolyte solution per hour, and the management of pain with intravenous boluses of morphine. The patient should also receive supplemental oxygen, and the burn wound should be covered by sterile drapes. Finally, every burn victim requires tetanus prophylaxis. Major burns and burn wounds at sensitive locations such as head and hands should be treated in specialized burn centers. This provides best chances for survival and increases the probability for a good cosmetic result.

Comparative effects of esmolol and labetalol to attenuate hyperdynamic states after electroconvulsive therapy.

We studied 18 patients (age range, 53-90 yr) with at least one cardiovascular risk factor who were treated with electroconvulsive therapy (ECT) and compared effects of five pretreatments: no drug; esmolol, 1.3 or 4.4 mg/kg; or labetalol, 0.13 or 0.44 mg/kg. Each patient received all five treatments, during a series of five ECT sessions. Pretreatment was administered as a bolus within 10 s of induction or anesthesia. Doses of methohexital and succinylcholine were constant for the series of treatments and the assignment to no drug or to drug and dose was determined by randomized block design. Measurements of systolic and diastolic blood pressure (SBP, DBP) and heart rate (HR) were recorded during the awake state and 1, 3, 5, and 10 min after the seizure. The deviation of ST segments from baseline was measured by an electrocardiogram (ECG) monitor equipped with ST-segment analysis software. The results (mean +/- SEM) show that without pretreatment, there were significant (P < 0.05) peak increases in SBP and HR (55 +/- 5 mm Hg and 37 +/- 6 bpm, respectively), recorded 1 min after the seizure. Comparable reductions (by approximately 50%) in these peak values were achieved after esmolol (1.3 mg/kg) or labetalol (0.13 mg/kg), and cardiovascular responses were nearly eliminated after the same drugs in doses of 4.4 and 0.44 mg/kg, respectively. The deviation of ST-segment values from baseline in any lead was not measurably influenced by either antihypertensive drug. SBP values were lower after labetalol 10 min after the seizure, but not after esmolol. Asystolic time after the seizure was not significantly longer with either drug.(ABSTRACT TRUNCATED AT 250 WORDS)

Genetic effects on the variability of the halothane and caffeine muscle contracture tests.

BACKGROUND: The spectrum of the clinical presentation of malignant hyperthermia (MH) and the results of recent linkage studies suggest that there is a degree of heterogeneity in MH susceptibility. In the current study, we analyzed in vitro muscle contracture tests from members of large families with MH to evaluate if the results of these tests could be related to genetic influences. METHODS: Forty-seven subjects from four families with an MH-related death and with at least five clinically MH-susceptible individuals per family, as diagnosed by an in vitro muscle contracture test according to the protocol of the European MH Group, were included in the current analysis. We compared the strength of muscle contractures to challenges of halothane, caffeine, or both and the effect of these two drugs on twitch potentiation in response to supramaximal electrical stimulation among the families. RESULTS: Clinical MH susceptibility was confirmed in 36 individuals, and 11 individuals were diagnosed as MH-negative. In MH-susceptible individuals, muscle contractures to the 2% halothane challenge were significantly higher in family 1 (n = 15; 16.2 +/- 2.9 mN, mean +/- standard error of the mean) and in family 4 (n = 5; 16.4 +/- 5 mN) than in family 2 (n = 9; 5.8 +/- 1.5 mN) or family 3 (n = 7; 6.0 +/- 1.1 mN). Muscle contractures to the caffeine challenge (2 mM) were significantly increased in family 1 (7.3 +/- 1.4 mN) compared with those in family 3 (1.3 +/- 1.0 mN). In addition, we found a dose-dependent twitch potentiation to the halothane challenge in family 2 (P < 0.01) and to the caffeine challenge in families 2 (P < 0.001) and 3 (P < 0.01), whereas there was no twitch potentiation in families 1 and 4. CONCLUSIONS: The differences of in vitro muscle contracture tests among several families with MH provide evidence for genetic influences on the variability of this test procedure. However, it is not known if the observed differences are caused by heterogeneity of the MH gene mutation(s) or by other genetic factors that might modify muscle contractures in vitro.

Prophylactic antiemetic therapy with patient-controlled analgesia: a double-blind, placebo-controlled comparison of droperidol, metoclopramide, and tropisetron.

This placebo-controlled, randomized, double-blind trial was designed to evaluate the efficacy of three prophylactic antiemetic regimens on postoperative nausea and vomiting (PONV) during patient-controlled analgesia (PCA) with morphine. We studied 286 elective surgical patients for 36 h postoperatively. Group 1 was saline control. In Groups 2 and 3, metoclopramide or droperidol was administered as an intravenous (i.v.) bolus and then added to morphine in the PCA device. In Group 4, tropisetron, a long-acting investigational 5-hydroxytryptamine subtype 3 (5-HT3) antagonist was given as a single i.v. dose. We assessed the frequency and severity of PONV, as well as the need for rescue, frequency of side effects, and overall patient satisfaction. Severity of PONV was measured with a symptom-severity score (STS) which was based on both intensity and duration. The average total doses of antiemetics were metoclopramide 53.8 +/- 2.2 mg, droperidol 5.99 +/- 0.3 mg, and tropisetron 6.1 +/- 0.2 mg. Control patients had a 54% incidence of PONV. Droperidol reduced both the incidence (P < 0.001) and severity (P < 0.01) of PONV for the entire 36 h. Tropisetron reduced incidence and severity (P < 0.05), but the effect of the single bolus dose lasted only 18 h. Metoclopramide had a marginally significant effect under these conditions. Only droperidol decreased the need for rescue medication (P < 0.01), although rescue with tropisetron was highly effective. Side effects and patient satisfaction were comparable among the groups, but patients receiving droperidol were sleepier (P < 0.05) than control patients and recalled somewhat more anxiety (P = 0.03).(ABSTRACT TRUNCATED AT 250 WORDS)

Is normal saline an acceptable alternative to silicone for lubricating fibrescopes?

This article describes a model designed to measure the forces acting on a fibrescope when it is pushed through an endotracheal tube. Lubrication with either silicone or normal saline leads to a reduction in friction forces. Fibrescopes lubricated with normal saline require a larger force to be advanced through endotracheal tubes when compared to silicone; however, the difference is clinically unimportant and is outweighed by the advantageous properties of normal saline. A theoretical model is presented which is in close agreement with experimentally derived data.

In vitro effect of ephedrine, adrenaline, noradrenaline and isoprenaline on halothane-induced contractures in skeletal muscle from patients potentially susceptible to malignant hyperthermia.

We have measured the effects of ephedrine, adrenaline, noradrenaline and isoprenaline on halothane-induced contractures in muscle biopsies from patients potentially susceptible to malignant hyperthermia (MH). At concentrations of 4-24 mmol litre-1, ephedrine induced in vitro contractures in halothane 0.44 mmol litre-1-prechallenged muscle, whilst adrenaline, noradrenaline and isoprenaline had no effect. There was a shift of the ephedrine concentration-response curve to the left and an increased maximum muscle contracture in the MH susceptible group compared with the MH negative group (P < 0.001). We conclude that ephedrine increased halothane-induced muscle contractures in vitro either by an unknown pharmacological mechanism or by an adrenergic stimulation which was different from those of the other investigated adrenoceptor agonists.

Severe head injury: should expected outcome influence resuscitation and first-day decisions?

An early 'prognosis' based on initial findings can influence clinical decisions. To evaluate the quality of first-day outcome prediction based on either clinical or neuroradiological information, we prospectively examined 100 consecutive severely head-injured patients from the surgical intensive care unit. The prognoses were always made by the same experienced neurosurgeon and neuroradiologist according to a contracted Glasgow Outcome Scale (GOS). Every patient's outcome was predicted according to a three-class GOS within 24 h after injury. Correct 'first-day' prognoses were made in 59 and 56% of the cases by the neuroradiologist and neurosurgeon, respectively. In those instances where the prognoses made by the clinician and the radiologist coincided, the prognoses were correct for 73% of the patients. Based on accepted criteria, the neuroradiologist tended to overpredict favorable outcomes and missed many of the unfavorable outcomes (dead or vegetative) whereas the clinician overestimated unfavorable outcomes. Our study showed that outcome prognosis of patients with severe head injury has limited accuracy when made within 24 h after the injury, although an improvement in accuracy occurred when there was agreement between clinical and radiological predictions. Even with sophisticated clinical and radiological technologies, it is not possible to predict outcome on the first day after the accident with sufficient accuracy to guide early management.

Does on-scene resuscitation affect in-hospital "do not resuscitate" decisions and mortality in patients with severe head injuries?

To evaluate the effect of on-scene versus in-hospital resuscitation of patients with severe head injuries with regard to "do not resuscitate" (DNR) decisions and in-hospital mortality, 561 patients were prospectively studied. Patients were grouped according to whether resuscitation initially occurred at the scene of the injury (group 1), in a regional hospital before transfer (group 2), or after direct admission to our neurosurgical center (group 3). The DNR and mortality rates within the first 48 hours (13%, 10%, 10%, respectively) as well as for the entire stay in the surgical intensive care unit (SICU) were comparable for the three groups. It has been pointed out that efficient resuscitation at the scene of the injury may, instead of improving overall outcome, increase morbidity and mortality rates because more severely injured patients now reach the hospital alive. We conclude, however, that primary aggressive treatment at the scene of the injury did not increase DNR and in-hospital mortality rates within the 48-hour follow-up period, nor for the total stay in the SICU. Investigation of long-term outcome will be important to further establish the efficacy of this approach.

[Severe craniocerebral injuries: northwestern Switzerland 1984-1989]. / Schwere Schädelhirntraumata: Nordwestschweiz 1984-1989.

Data from 561 severely head-injured patients treated in a Surgical Intensive Care Unit between 1984 and 1989 are analyzed. Age and sex distribution of the patients was comparable to findings in other studies. More than half of the patients were injured in road accidents, accidents involving cars representing the greatest risk. In 90% of all patients, severe head injury was the primary diagnosis. 60% of the patients were intubated within 30 minutes at the scene of the accident, as opposed to 17% of patients intubated in the emergency room within the same time interval. Patients resuscitated at the scene of the accident and admitted directly by helicopter arrived at the emergency room on average one hour after the accident; for those transported directly by ambulance, without intubation prior to admission, the average time interval was half an hour. Since the time interval between accident and onset of resuscitation is crucial, this difference in transportation times is not considered to be of major importance. Half of the patients who died in the Surgical Intensive Care Unit died within the first 48 hours, usually from primary severe brain damage. In 50% of the 446 patients from the first 4 years of this study the recoveries ranged from good to complete and 28% died. Only 3 (less than 1%) out of 446 patients were alive in a vegetative state, and 8% severely handicapped one year after the accident. Aggressive primary treatment did not increase the number of patients surviving in a vegetative or severely handicapped state.