Urinary tract infection following ritual Jewish circumcision

Circumcision seems to reduce the overall incidence of urinary tract infections (UTI), although a few studies have suggested that ritual circumcision may be a predisposing factor for UTI within the first 2 weeks following the procedure. The aim of this study was to investigate a possible causal relationship between ritual circumcision and UTI. The study comprised 82 infants with UTI, 55 females and 27 males under the age of 1 year. All males were circumcised on the eighth day of life. The median age of infection was 0.75 and 7.0 months for males and females, respectively. Fifty-two percent (14/27) of UTI episodes were diagnosed within the 2 weeks following circumcision. A significantly lower incidence in Escherichia coli-induced UTI was observed in males compared to females, 67% and 93%, respectively. Similarly, the incidence of E. coli-induced UTI was also significantly lower in males presenting within 2 weeks following circumcision (57%) compared to infants presenting prior or more than 2 weeks following the procedure (92%). Positive blood cultures of an identical microorganism were observed in 6/27 males compared to 2/55 females. The incidence of urinary tract malformations and their severity were similar in both sexes. We conclude that the high incidence of UTI following a ritual Jewish circumcision, as well as the relatively high preponderance of bacteria other than E. coli, may suggest a causal relationship between circumcision and UTI.

Role of the gut in the pathophysiology of extrahepatic biliary obstruction

BACKGROUND

Gram negative septic events are the commonest source of morbidity and mortality as a result of surgery in jaundiced patients. The large intestine provides the major source of Gram negative bacteria in mammals and is implicated in the pathogenesis of systemic endotoxaemia in obstructive jaundice. Bile salts have an important part in maintaining indigenous microecological homeostasis through their emulsifying properties.

AIMS

The aim was to investigate the effects of biliary obstruction and isolated external biliary diversion on gastro-intestinal structure and caecal bacterial flora in relation to bacterial translocation.

METHOD

Six groups of adult male Wistar rats were studied (no operation, sham operated, and bile duct ligated (BDL) for one and three weeks and a choledocho-vesical fistula (CDVF) for one week). At the end of the study period plasma was assayed for evidence of endotoxaemia and the animals were tested for bacterial translocation to the mesenteric lymph node complex (MLNC), liver, lungs, and spleen. Quantitative and qualitative bacteriological studies were performed on the caecal contents and segments of colon and terminal ileum were washed and prepared for histological assessment.

RESULTS

Bacterial translocation was significantly increased in the BDL1 (68.8%) and BDL3 (60%) groups compared with the sham1 (6.3%), sham3 (9.1%), No operation (0%), and CDVF1 (16.7%) groups. Although translocation was more pronounced in the BDL1 group, this was almost exclusively to the MLNC compared with the more widespread translocation to other organs in the BDL3 group. The BDL3 group was the only group with significantly raised concentrations of endotoxin and anticore glycolipid. The caecal Gram negative aerobic counts were significantly increased in the BDL1 and CDVF1 groups compared with all other groups. There was evidence of structural abnormalities in the terminal ileum of rats jaundiced for three weeks, but not in the other groups.

CONCLUSIONS

Biliary obstruction for one and three weeks promotes bacterial translocation although the mechanisms may be different. Absence of intralumenal bile results in a significant but self limiting increase in the Gram negative aerobic population, which may account for translocation in the early stages of biliary obstruction. As the duration of biliary obstruction increases systemic endotoxaemia is a consistent feature which, combined with factors such as immunological depression and physical disruption of gut barrier function, may promote bacterial translocation perpetuating systemic sepsis.

Dumping syndrome following Nissen fundoplication, diagnosis, and treatment

We evaluated the prevalence, diagnosis, and treatment of dumping syndrome (DS) following Nissen fundoplication in 50 consecutive infants and children who underwent the operation for gastroesophageal reflux. Examination included a preoperative dietary assessment with emphasis on specific postprandial clinical symptoms and technetium scintigraphy to evaluate gastric emptying. In the immediate postoperative period, postprandial glucose levels were examined in all patients with symptoms clinically suggestive of DS. In the late postoperative period (6 months to 5.5 years), all patients with more than one specific clinical symptom of DS were further evaluated by glucose tolerance test (GTT), HbA1C levels, and gastric technetium scintigraphy. DS was diagnosed in 15 patients (30%). Five patients had immediate severe DS (SDS), and 10 in the late postoperative course had latent postoperative DS (LDS). In all patients with DS, preoperative and postoperative gastric emptying scan T1/2 did not show any statistical significance. High levels of HbA1C ranging from 7.9 to 9% (mean, 8.25 +/- 0.5) were found in only three patients. Treatment included parenteral nutrition in one patient. All the others were successfully managed with nutritional manipulation alone, using a combination of lactose-free formula and fat emulsion. In patients whose postprandial symptoms persisted, pectin 5-15 g/day divided into six doses was added to the diet. Following 6 months of dietary treatment, the postprandial normoglycomic response was restored. Eleven patients experienced complete resolution of symptoms (78.5%), and three patients (21.4%) showed significant clinical improvement. This study indicates that DS is a common complication following Nissen fundoplication. The GTT is the most reliable examination for establishing the diagnosis. Treatment is simple and effective. The technetium gastric emptying scan and HbA1C level do not play a significant role in the diagnosis.

Routine childhood screening for hyperlipidemia in Israel

Screening of children and adolescents for hyperlipidemia is controversial. We performed a cholesterol surveillance study of 806 children aged between 6 and 14 years. The initial cholesterol screening test was done by finger stick in the non-fasting state. Children with cholesterol values exceeding 4.55 mmol/l ("borderline" risk) and their parents had their lipid profiles measured following a 12 h fast by venipuncture. The incidence of coronary risk factors in the families of children with hypercholesterolemia was estimated. Of the initial group, 71 children had total capillary cholesterol levels > or = 4.55 mmol/l, and in 65 of these children serum lipid profile was reexamined after an overnight fast. Fifty-five children were found to have total venous cholesterol (TVC) levels < 4.55 mmol/l, and 27 of the 55 had a low density lipoprotein (LDL) cholesterol level > 3.4 mmol/l ("borderline" risk). A positive correlation was found between TVC and LDL-cholesterol levels. Of the hypercholesterolemic children 49% had a parent with hyperlipidemia and 13% had a family history of premature myocardial infarction (before 55 years of age). We conclude that screening of children based on the presence of hypercholesterolemia or its possible complications in other family members may fail to identify many of the children with hypercholesterolemia. Thus, if thorough identification of young children with hypercholesterolemia is desired, inclusive population screening would be the most effective approach.

Severe pseudohypoaldosteronism in a pair of twins not associated with hydramnios

A pair of non-identical twins with severe pseudohypoaldosteronism (PHA) were followed over a period of 4 years. The diagnosis was based on dehydration, hyponatremia, hyperkalemia, high urine sodium/potassium ratios, and high serum concentrations of aldosterone and renin. Sweat and saliva electrolyte concentrations were high, suggesting multifocal target-organ unresponsiveness to mineralocorticoids. No hydramnios was observed during pregnancy. Despite continuous treatment with sodium chloride and sodium bicarbonate (< or = 20 g/day) and cation exchange resin (Kayexalate, sodium polystyrene sulfonate, < or = 4 g/kg per day), the children had repeated episodes of dehydration, hyponatremia, and hyperkalemia. Growth velocity was normal in both twins. Catch-up growth was observed following infancy in the first twin. Normalization of plasma aldosterone, electrolytes, and renin concentrations was achieved at the age of 9 months.

Remifentanil versus alfentanil: comparative pharmacokinetics and pharmacodynamics in healthy adult male volunteers

BACKGROUND

Remifentanil is an esterase-metabolized opioid with a rapid clearance. The aim of this study was to contrast the pharmacokinetics and pharmacodynamics of remifentanil and alfentanil in healthy, adult male volunteers.

METHODS

Ten volunteers received infusions of remifentanil and alfentanil on separate study sessions using a randomized, open-label crossover design. Arterial blood samples were analyzed to determine drug blood concentrations. The electroencephalogram was employed as the measure of drug effect. The pharmacokinetics were characterized using a moment analysis, a nonlinear mixed effects model (NONMEM) population analysis, and context-sensitive half-time computer simulations. After processing the raw electroencephalogram to obtain the spectral edge parameter, the pharmacodynamics were characterized using an effect compartment, inhibitory maximum effect model.

RESULTS

Pharmacokinetically, the two drugs are similar in terms of steady-state distribution volume (VD(SS)), but remifentanil's central clearance (CLc)) is substantially greater. The NONMEM analysis population pharmacokinetic parameters for remifentanil include a CLc of 2.9 l x min(-1), a VDss of 21.81, and a terminal half-life of 35.1 min. Corresponding NONMEM parameters for alfentanil are 0.36 l x min(-1), 34.11, and 94.5 min. Pharmacodynamically, the drugs are similar in terms of the time required for equilibration between blood and the effect-site concentrations, as evidenced by a T(12)k(e0) for remifentanil of 0.75 min [corrected] and 0.96 min for alfentanil. However, remifentanil is 19 times more potent than alfentanil, with an effective concentration for 50% maximal effect of 19.9 ng x ml(-1) versus 375.9 ng x ml(-1) for alfentanil.

CONCLUSIONS

Compared to alfentanil, the high clearance of remifentanil, combined with its small steady-state distribution volume, results in a rapid decline in blood concentration after termination of an infusion. With the exception of remifentanil's nearly 20-times greater potency (30-times if alfentanil partitioning between whole blood and plasma is considered), the drugs are pharmacodynamically similar.

Renal and absorptive hypercalciuria: a metabolic disturbance with varying and interchanging modes of expression

BACKGROUND

In previous studies, the oral calcium loading and deprivation test has been used to distinguish between children with renal (fasting) hypercalciuria (RH) and absorptive hypercalciuria (AH).

OBJECTIVE

We evaluated the long-term clinical course of 30 children with idiopathic hypercalciuria and investigated the influence of urinary sodium excretion, as a reflection of its intake, on urinary calcium excretion.

METHODS

Thirty normocalcemic, normophosphatemic children (21 boys and 9 girls) with urinary calcium to creatinine ratios greater than 0.57 mmol/L/mmol/L ( > 0.21 mg/dL/mg/dL on the three consecutive examinations participated in this study. They were divided according to their responses to calcium deprivation and loading into AH (16 patients) and RH (14 patients).

RESULTS

When restudied 3 to 7 years later, 6 of the 16 children with AH were normocalciuric and three demonstrated characteristics compatible with RH. The remaining seven patients maintained their initial AH pattern. Of the 14 children with RH, four were normocalciuric and four demonstrated AH. The remaining six children maintained their initial RH pattern. A significant positive correlation was observed between urine sodium and calcium excretion in children with AH or RH. Children who were normocalciuric at the second study had significantly lower values of urine sodium excretion when compared with those in whom hypercalciuria persisted.

CONCLUSIONS

We suggest that AH and RH constitute a continuum. The change in characteristics observed during the second study suggests that any attempt to divide these patients into two physiologically distinct subtypes may be artificial. The main factor influencing urinary excretion of calcium in our patients seemed to be sodium intake.

Subcuticular skin closure as a standard approach to emergency appendectomy in children: prospective clinical trial

We evaluated the morbidity associated with primary closure by interrupted subcuticular absorbable sutures following emergency appendectomy. In a prospective clinical trial over a 12-month period, 216 children who underwent emergency appendectomy had skin closure using subcuticular interrupted absorbable polyglactin 4-0 sutures. Preoperative prophylactic antibiotics consisting of metronidazole alone or in combination with gentamicin were used in patients with suspected phlegmonous appendicitis; a combination of metronidazole, gentamicin, and ampicillin was used when perforation of the appendix was suspected. Postoperatively, in patients with phlegmonous appendicitis metronidazole was given for 24 hours, whereas in those with peritonitis the triple antibiotics were continued for 7 to 10 days. All patients were assessed for complications resulting from the technique of wound closure. No intraabdominal abscesses or serious complications were recorded. The overall incidence of wound infection was 1.8%. Among children with a perforated appendix the rate of superficial wound infection was 5.7%. There was no difference in the rate of wound infection between patients who received metronidazole alone or metronidazole plus gentamicin preoperatively. All the patients and their families were satisfied with the cosmetic results and with the fact that removal of skin sutures was unnecessary. We conclude that the use of prophylactic antibiotics permits standard skin closure by interrupted absorbable subcuticular suture.

Peritoneal ventilation in rabbits: augmentation of gas exchange with cisapride

BACKGROUND

Peritoneal ventilation has been shown to be effective in achieving extrapulmonary oxygenation and carbon dioxide elimination in an animal model of severe adult respiratory distress syndrome (ARDS). Cisapride is a "prokinetic" agent (increases gastric emptying), that may increase the splanchnic circulation and thus favourably affect gas exchange in peritoneal ventilation.

METHODS

Using Doppler ultrasound the effect of cisapride on the portal venous circulation was examined in eight spontaneously breathing rabbits and the effect of cisapride on gas exchange in five rabbits spontaneously breathing room air was compared with that of a control group who did not receive cisapride. Its effect on gas exchange in five rabbits with ARDS being treated with mechanical lung and peritoneal ventilation was compared with that of a control group, and its effect on gas exchange in five rabbits with ARDS treated with conventional ventilation was also compared with that of a control group.

RESULTS

Enteral administration of cisapride increased portal venous blood velocity, as measured ultrasonographically, by a mean of 188% one hour after receiving the drug. In rabbits with ARDS being treated with both peritoneal ventilation and mechanical ventilation to the lungs, those receiving cisapride had arterial oxygen tensions 1.5-3 times that of controls. Cisapride had no effect on arterial blood gas tensions in rabbits who were spontaneously breathing room air, nor in rabbits with ARDS who received only conventional mechanical lung ventilation.

CONCLUSIONS

Cisapride increases arterial oxygenation in rabbits with severe ARDS treated with peritoneal ventilation, probably due to its ability to increase splanchnic circulation. It should be considered as an adjuvant medication to peritoneal ventilation.

Characterisation of the interaction between the nucleoprotein and phosphoprotein of pneumonia virus of mice

A protein blotting technique was used to study the interaction occurring between the pneumonia virus of mice N protein and other PVM encoded proteins expressed in infected cells. Measurement of the degree of binding indicated that the N protein specifically interacted only with the full-length 39 kDa P protein in infected cells. Truncated N-related proteins were synthesised in vitro and incubated with filter-bound full-length and truncated P proteins. The data suggested that many regions of the N protein are cooperatively involved in the binding process. It was also determined that both the amino and the carboxyl-terminal regions of the PVM P protein were essential for binding to N protein.

Effects of adrenaline and hyaluronidase on plasma concentrations of lignocaine and bupivacaine after peribulbar anaesthesia

We have measured peak plasma concentrations of lignocaine and bupivacaine after dual injection peribulbar block and investigated the influence of adrenaline and hyaluronidase. Twenty-four patients were allocated randomly to one of four groups: (I) local anaesthetic alone (lignocaine 10 mg ml-1-bupivacaine 3.75 mg ml-1); (II) local anaesthetic with adrenaline (5 micrograms ml-1); (III) local anaesthetic with hyaluronidase (75 iu ml-1); or (IV) local anaesthetic with adrenaline and hyaluronidase. Venous plasma concentrations of lignocaine and bupivacaine were measured in 24 patients using gas liquid chromatography before and at 5, 10, 15, 20, 25, 30, 45, 60, 90, 120, 180, 300 and 540 min after completion of the peribulbar injections. Main outcome measures were analysed using two-way analysis of variance. All patients, with one exception, received 10 ml of the local anaesthetic mixture. Overall peak plasma concentrations varied from 230 to 1910 micrograms ml-1 for lignocaine and from 160 to 1090 micrograms ml-1 for bupivacaine. Adrenaline significantly reduced peak plasma concentrations of lignocaine to 57% (P = 0.001) and bupivacaine to 61% (P = 0.004) compared with the nonadrenaline groups. Hyaluronidase had no significant effect on peak plasma concentrations of lignocaine and bupivacaine, which were 90% (P = 0.34) and 100% (P = 0.84) of the non-hyaluronidase groups. The area under the plasma concentration-time curves to 300 min (AUC300) behaved similarly. There was a reduction in AUC300 for lignocaine (P = 0.005) and bupivacaine (P = 0.011) in the adrenaline groups compared with the non-adrenaline groups, in contrast with no significant effects of hyaluronidase on AUC300 for lignocaine (P = 0.14) or bupivacaine (P = 0.53) compared with the non-hyaluronidase groups.

Investigative approach to frog gastrocnemius laboratory: potential impact on animal use in teaching laboratories

With growing concern over the use of animal experimentation in the teaching of physiology, many biology departments are reassessing the use of animal experiments in the teaching lab. However, it may be just as important to assess how animal experimentation is used in the undergraduate teaching laboratory rather than simply assessing if animal experimentation should be used at all. In our study, sophomore-level life science students enrolled in a core organismal biology course undertook a laboratory exercise designed to elucidate properties of muscles and neuromuscular communication following two protocols: 1) a standard demonstrational model wherein students were told to undertake the exercise as a means to understand physiological processes that they had been exposed to previously in lecture or 2) an investigative model wherein the use of the gastrocnemius preparation was a logical next step in an ongoing investigation, the content of which was driven by student-generated hypotheses. We have observed a significant decrease in a number of the negative comments concerning the use of animals in experimentation (25.6 vs. 3.6%) since the implementation of the investigative approach to the laboratory, suggesting that curricular approaches to the use of animals in the teaching laboratory may have an impact on student attitudes concerning animal experimentation.

Short note: the potential of umbilical cord blood to increase tissue oxygenation in adult respiratory distress syndrome

Umbilical blood, consisting mainly of fetal haemoglobin, has an increased oxygen affinity. Adult respiratory distress syndrome may be caused by any acute, diffuse, infiltrative lung lesion of diverse aetiologies and is characterized by severe arterial hypoxia. Mechanical ventilation with high FIO2 and elevated pressures is used to improve tissue oxygenation in these patients. Nevertheless, adult respiratory distress syndrome may be fatal. Our hypothesis suggests that transfusion of umbilical cord blood to adult respiratory distress syndrome patients may facilitate oxygen transport by increasing oxygen binding in the erythrocytes passing through the damaged lungs. The local hypoxia and the accompanied acidosis in the periphery may accelerate the oxygen unload to the tissues, thus augmenting overall oxygen delivery. Studies with animals and humans show that left-shifted oxyhaemoglobin dissociated curve confers a degree of adaptation to low-oxygen tension ambient. Umbilical cord blood is available in every hospital, and there are no contraindications to its use.

Focal epileptic episodes associated with hypoglycemia in children with diabetes

Focal neurological deficits associated with hypoglycemia have been well described in adults with diabetes. We could find only one report of the association between focal epileptic episodes and hypoglycemia in children with diabetes. We describe 3 patients with seven focal epileptic episodes associated with hypoglycemia.

Photodecomposition of 1,2,3,4- and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in water-alcohol media on a solid support

We used a hydrophobic solid support, octadecylsilylated silica gel (C18), packed in a quartz column as a reaction medium for the photolysis of 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD) and 1,2,3,4-tetrachlorodibenzo-p-dioxin (1,2,3,4-TCDD). When we exposed the column to a 450 W UV lamp, the adsorbed 1,2,3,4-TCDD or 2,3,7,8-TCDD in 10% 2-propanol/water decomposed completely in 20 minutes and 5 minutes, respectively. The large estimated partition coefficient of 1,2,3,4-TCDD in 10% 2-propanol/water (> 1000) indicates that on the C18 stationary phase, both the saturated hydrocarbon chains and the absorbed 2-propanol may act as proton donors and accelerate the photolysis. In direct sunlight, the adsorbed 1,2,3,4-TCDD in 10% 2-propanol/water decomposed much faster than in a nonaqueous solvent (50% 2-propanol/methanol). This solvent effect is advantageous for the practical use of the C18 photolysis process in aqueous waste treatment. We have demonstrated that complete C18 trapping with continuous photodecomposition of TCDD contained in an aqueous alcohol waste is possible.

The pharmacokinetics of 8-methoxypsoralen following i.v. administration in humans

1. 8-methoxypsoralen (8-MOP) is a naturally occurring photoreactive substance which, in the presence of u.v. light, forms covalent adducts with pyrimidine bases in nucleic acids. For many years, 8-MOP has been used in PUVA therapy for treatment of psoriasis. Recently, the drug has been found to inactivate effectively bacteria spiked into platelet concentrates. The purpose of this study was to determine the pharmacokinetics and safety of 8-MOP administered intravenously in the bactericidal dosage range. 2. Eighteen volunteers were divided into three treatment groups to receive, respectively, 5, 10, and 15 mg 8-MOP infused over 60 min. Frequent arterial samples were gathered, and the blood and plasma were assayed for 8-MOP concentration. The pharmacokinetic parameters were determined by moment and compartmental population analysis, the latter performed with the program NONMEM. Haemodynamics, ventilatory pattern, and subjective effects were recorded throughout the study. 3. The intravenously administered 8-MOP was well tolerated in all individuals, and no acute toxicity was observed. 4. The pharmacokinetics of 8-MOP were best described by a three-compartment mammillary model in which the volumes and clearances were proportional to weight. The mean pharmacokinetic parameters for the plasma concentrations were: V1 = 0.045 1 kg-1, V2 = 0.57 1 kg-1, V3 = 0.15 1 kg-1, CL1 (systemic) = 0.010 1 kg-1 min-1, CL2 = 0.0067 1 kg-1 min-1, CL3 = 0.012 1 kg-1 min-1. The mean pharmacokinetic parameters for the blood concentrations were: V1 = 0.061 1 kg-1, V2 = 1.15 1 kg-1, V3 = 0.21 1 kg-1, CL1 (systemic) = 0.015 1 kg-1 min-1, CL2 = 0.011 1 kg-1 min-1 and CL3 = 0.015 1 kg-1 min-1. 5. The plasma pharmacokinetic model described the observations with a median absolute error of 17%, and the blood pharmacokinetic model described the observations with a median absolute error of 18%. Analysis of the relative concentration of 8-MOP between plasma and red blood cells suggested concentration-dependent partitioning. 6. The addition of 7.5 mg 8-MOP to 300 ml platelet concentrate would produce bactericidal concentrations of 25 micrograms ml-1. Simulations based upon our data show that intravenous administration of 7.5 mg over 60 min would result in systemic concentrations of 8-MOP similar to those observed with conventional PUVA therapy. We conclude that the extensive safety history established in PUVA therapy will be applicable to this new application of 8-MOP.

Optimal intravenous dosing strategies for sedatives and analgesics in the intensive care unit

Achieving and maintaining adequate levels of analgesia and sedation in critically ill patients is a fundamental part of ICU care. Understanding the clinical pharmacology of commonly used sedative agents (e.g., midazolam, lorazepam, and propofol) and opioids (e.g., fentanyl and morphine) enables clinicians to best dose these drugs to the desired clinical effect while minimizing the risk of excessive sedation and cardiopulmonary depression. This has significant safety and cost implications for patient care in the ICU. Simulations of plasma concentrations of these medications when administered to ICU patients provide useful insight into the clinical pharmacology of these agents. A number of points should be made with regards to the interpretation of these predicted plasma concentrations, however. First, it is important to remember that PK parameters for most of these agents, with the exception of midazolam and propofol, were derived from bolus or short-term infusions administered to healthy patients, and that the PK parameters for lorazepam, fentanyl, and morphine when administered as long-term infusions to critically ill patients may vary dramatically from these initial estimates. Specifically, their volumes of distribution and elimination half-lives may prove to be significantly larger and longer, respectively, when administered to patients in the ICU. This pharmacokinetic variability may result in even longer emergence times than predicted herein following discontinuation of continuous infusions of these agents. Until similar studies in ICU patients are performed for lorazepam, fentanyl, and morphine, the clinical pharmacology of these agents in ICU patients remains uncertain. Additionally, midazolam and morphine both have active metabolites that can accumulate in critically ill patients receiving long-term infusions. These metabolites add significantly to the sedative effects of the primary compound. Other drugs with sedative effects given concurrently with any of these agents (i.e., psychotropic agents, epidural opioids, etc.) may also contribute to the sedative effects of these drugs. These studies do not account for the development of tolerance (which can occur with both benzodiazepines and opioids) or changing kinetic profiles within an individual patient over time (i.e., due to changes in volume of distribution, protein binding, or clearance). Finally, there is a high degree of interpatient variability among critically ill patients, and medication dosing must be tailored to individual patients' needs (i.e., one dose does not fit all patients). Given the uncertainty of resulting plasma concentrations with long-term administration of these medications, the best ways to achieve and maintain optimal levels of sedation and analgesia while minimizing the risk of oversedation and side effects are to (1) initiate sedation in an incremental fashion until the desired level of sedation is achieved, then periodically (i.e., once a day) titrate the infusion rate of sedative-hypnotics and opioids downward until the patient begins to emerge from the sedative effects of these drugs; and finally gradually increase the infusion rate until the desired level of sedation is once again achieved; and (2) consider the use of a sedation scale to standardize the level of sedation to be maintained (see Table 3). The use of such a scale enables physicians to communicate to nursing staff the specific level of sedation to be achieved and maintained in an individual patient (i.e., titrate the midazolam infusion between 0 to 5 mg/hr to maintain a sedation score of 2-3; call MD for inadequate sedation, respiratory depression, or hypotension). Achieving optimal sedation and analgesia of patients in the ICU requires not only that the choice of medication(s) be appropriate for the clinical setting but also that there are specific clinical endpoints for the agents used (i.e., light versus deep sedation, continuous versus intermittent sedation, sedation with