Hourly Output Research Articles

The Change in Renal Replacement Therapy on Acute Renal Failure in a General Intensive Care Unit in a University Hospital and its Clinical Efficacy: A Japanese Experience

The aim of our study was to examine renal replacement therapies (RRT) that have been used for acute renal failure (ARF) in our intensive care unit (ICU) patients and to compare their outcomes. Sixteen patients who underwent intermittent hemodialysis (IHD), 14 patients who underwent continuous hemofiltration (CHF) in combination with IHD (CHF + IHD), and 38 patients who underwent continuous hemodiafiltration (CHDF) were evaluated. Regarding the effects of blood purification on hemodynamics and renal function, the percentage increase in blood pressure and percent rapid increase in urinary output were the greatest in the CHDF group. The hourly urinary output after the start of initial blood purification increased only in the CHDF group. The survival rate was significantly higher in the CHDF group. These results suggest that CHDF should be the first-line therapy for patients with ARF and that we are moving in the right direction regarding the application of RRT to treat ARF in ICU patients.

Intra-abdominal pressure monitoring in liver transplant recipients: a prospective study.

No data are available on the incidence and clinical relevance of increased intra-abdominal pressure after orthotopic liver transplantation. This study assessed abdominal hypertension in a population of transplanted patients as this may be an important cofactor in early postoperative complications. Prospective clinical study in an intensive care unit of a national health system teaching hospital Abdominal pressure was measured every 6 h using the urinary bladder method and was considered elevated when it was 25 mmHg or higher. Hemodynamic status was evaluated at the same times. Renal function was assessed on the basis of hourly urinary output by calculating serum creatinine on postoperative days 2 and 4 and the filtration gradient; patient outcomes were also considered. Intra-abdominal hypertension was observed in 32% of cases; the subjects with high abdominal pressure had significantly lower mean artery pressure values but did not differ in terms of central venous pressure or cardiac output. High intra-abdominal pressure was more frequently associated with renal failure, a lower filtration gradient, delayed postsurgical weaning from ventilation, and a worse outcome. Abdominal hypertension is frequent after liver transplantation and may be associated with a complicated post-operative course.

Measurement of Cerebrospinal Fluid Output through External Ventricular Drainage in One Hundred Infants and Children: Correlation with Cerebrospinal Fluid Production

Objective: Cerebrospinal fluid (CSF) production rates influence shunt design and the care of children with hydrocephalus. Measurement of hourly CSF output through external ventricular drainage (EVD) reflects the CSF production. In the present study, hourly CSF outputs in children with hydrocephalus were measured while they were treated with EVD and correlated with the age, sex and body weight of the patients as well as other clinical parameters. Methods: One hundred children with hydrocephalus due to various causes had EVD treatment. Twenty-six had EVD on two or three separate occasions; thus, the CSF output measurements were observed and analyzed on the basis of 130 EVDs. The most common reason for EVD treatment was shunt infection (n = 75). The duration of EVDs ranged from 25 to 774 h (mean 269 h). The height of the drip chamber from the mid-head position ranged from 0 to 23 cm (mean 9.8 cm). The hourly CSF output was analyzed according to the patient’s age, sex and body weight as well as the presence of CSF infection. Results: The hourly CSF output rapidly increases during the first year of life. By the second year, it reaches 64% of the hourly CSF output of 15-year-old children. The mean hourly output ranged from 0.1 to 26.5 ml/h (mean 8.1 ml/h), with the standard deviation ranging from 0.4 to 10.8 ml/h (mean 5.2 ml/h). A regression analysis indicated that the age and body weight appeared to correlate with the hourly CSF output. Using the natural logarithm of age, body weight and sex, these predictors accounted for 50.9% of the variability in hourly CSF output. The regression equation is as follows: hourly CSF output = 2.78 – 2.23(male = 0, female = 1) + 0.97 log(age in years) + 2.26 log(body weight in kg). R sd = 3.36, R² = 0.509. The type of infecting organism and the height of EVD did not influence the overall CSF output. Conclusion: The hourly CSF output fluctuates, but the CSF output increases logarithmically with age and body weight. The gender also influences the CSF output, with males having a greater output than females. The data produced by the present study will help us to understand CSF production rates in developing children. They will also help us in the care of children receiving EVD treatment, as well as in selecting and designing shunt systems.

Transthoracic intracardiac catheters in pediatric patients recovering from congenital heart defect surgery: associated complications and outcomes.

To characterize transthoracic intracardiac catheter uses and associated morbidities in pediatric patients recovering from congenital heart defect surgery and to identify potential risk factors associated with their use. Prospective data collection and review. An 18-bed pediatric intensive care unit (PICU) in a tertiary care university hospital. All pediatric patients between October 1, 1996, and September 30, 1997, who were recovering from congenital heart defect surgery and had transthoracic intracardiac catheters in place. Catheter use, associated morbidity, necessary interventions, and risk factors for complications of catheter use were identified. During this period, 523 catheters (276 right atrial, 155 left atrial, 68 common atrial, and 24 right ventricular or pulmonary artery catheters) in 351 PICU patients were studied. Mean age was 23.1+/-45.1 months (median, 4.98 months); 138 patients (39.3%) were <3 months old. The rate of occurrence of bleeding with catheter removal (mediastinal output in the hour after removal that was more than twice the previous average hourly output) was 36.7%, and bleeding occurred more frequently with left atrial catheters (47%; odds ratio, 2.0; p < .05). However, interventions after catheter removal were required for only 8.3% (42/504) of catheters removed, and hemodynamic compromise occurred with the removal of only 2.6% (13/504) of catheters. Interventions included fluid resuscitation (35 cases), pleural drainage (three cases), catheter wiring for retention (one case), chest tube suctioning (two cases), and surgical removal (one case). No associated deaths occurred. In a multivariate logistic regression analysis, age <3 months (odds ratio, 4.74), catheter location (left atrial: odds ratio, 4.97; pulmonary artery: odds ratio, 12.48), and platelet count of <50,000 (odds ratio, 8.59) were identified as risk factors associated with a need for intervention after catheter removal (p < .05). Other complications included blood cultures positive for organisms (1.5%), thrombus (0.6%), and catheter nonfunction (10.9%). Prematurity was a risk factor for thrombus and nonfunction. Use of transthoracic intracardiac catheters in pediatric patients is safe. Young infants and pediatric patients with thrombocytopenia or with catheters in the left atrial or pulmonary artery position have a greater need for interventions after catheter removal, warranting added precautions.

Outdoor testing and solar simulation for oxazine 750 laser dye luminescent solar concentrator

A single dye luminescent solar concentrator (LSC) has been prepared using oxazine 750 dye and PMMA, dissolved in benzene. The solar simulation of the LSC has been performed at four different positions using an X–Y tracker. The hourly output power and global solar radiation has also been measured for a full year from April 1995 to March 1996, considering day 21 as a reference day. The output power curves were studied for each month separately and averaged through four seasons, Summer, Autumn, Winter, and Spring. The optical efficiency was also calculated and discussed. To test the field performance expectations for the LSC used, nonlinear correlations between horizontal data and some other positions have been also carried out and discussed.

The effect of single-dose non-steroidal anti-inflammatory drugs on urinary output

Objective: To compare the effect on urinary output of a single dose of three drugs (two non-steroidal anti-inflammatory drugs (NSAIDs) and a non-narcotic analgesic without known effects on the kidney) in an intensive care unit (ICU) selected population. Design: Prospective randomized study. Setting: A four bed surgical-medical ICU in a 960 bed teaching hospital. Subjects and interventions: Patients on the ICU for at least 24 h without arterial hypotension, abnormal renal function or coagulation, and who required an analgesic were randomly assigned to receive a single intravenous administration of ketorolac 30 mg (group KR), ketoprofen 100 mg (group KP), or propacetamol 2 g (group PP). The hourly urinary output was measured before drug administration and during the following 12 h. Arterial pressure, heart rate, central venous pressure and axillary temperature were measured before and after the analgesic administration. The values of blood urea, creatinine and potassium measured on the day of analgesic infu...

Relations between body weight, feed intake, daily weight gain, and exocrine pancreatic secretion in chronically catheterized growing pigs.

The aim of this investigation was to develop models that would make it possible to correct exocrine pancreatic secretion data for the effect of BW and feed intake in growing pigs. In addition, the significance of exocrine pancreatic secretion for daily weight gain (DWG) was studied. Data were used from 10 pigs (16 to 32 kg BW) surgically fitted with chronic pancreatic catheters. The samples were collected under controlled conditions for two to five experimental days per animal (a total of 39 observations), during 2 h preprandially and during 2 h when feeding (postprandially). The exocrine pancreatic secretion traits included the hourly output of volume, the amount of protein, and trypsin and amylase activities. Multiple linear regressions were used to develop models to describe exocrine pancreatic secretion. The individual pig was the most important source of variation in the model. With increasing BW, 7 out of 10 pigs showed an increase in exocrine pancreatic secretion. However, the slopes of the regression lines differed between animals, which made it impossible to develop general models for the correction of secretion data for the effect of BW. Postprandial exocrine pancreatic secretion was always higher than preprandial secretion, but the amount of feed intake per se did not seem to affect secretion. Exocrine pancreatic secretion and DWG were positively correlated. We concluded that, under the present circumstances, expressing secretion per kilogram BW or kilogram feed intake was not feasible. Expressing secretion per hour was the best way to present the data.

Marginal Zinc Deficiency Lowers the Lymphatic Absorption of α-Tocopherol in Rats ,

The present study was conducted to investigate whether the intestinal absorption of vitamin E is influenced by marginal zinc deficiency. Rats trained to meal feed were divided into two groups and fed a diet containing 3 mg Zn/kg [a low zinc (LZ group)] or pair-fed (PF controls a zinc-adequate diet (30 mg Zn/kg). At 5 wk, the body weight (352 ± 5 g, mean ± SD) of LZ rats was 98.5% of that of PF rats (357 ± 8 g). Rats with lymph cannula were infused at 3 mL/h via a duodenal catheter with a lipid emulsion consisting of 568 μmol triolein, 3.56 μmol α-tocopherol (αTP) and 396 μmol Na+-taurocholate in 24 mL of phosphate-buffered saline (pH 6.4). Lymph was collected hourly for 8 h. The amounts of αTP absorbed into the lymph were determined by high-performance liquid chromatography (HPLC). The hourly rate of αTP absorption was significantly lower in LZ than in PF rats. A marked difference (P < 0.05) was clearly evident even at 1 h (1.8 ± 1.2 nmol/h in LZ vs. 8.5 ± 3.0 nmol/h in PF). The peak rate of absorption was significantly lower in LZ rats (67.1 ± 16.7 nmol/h at 5 h) than in PF rats (95.9 ± 7.7 nmol/h at 4 h). The total amounts of αTP absorbed in 8 h in LZ and PF rats were 391.1 ± 54.4 nmol (11.0 ± 1.5% dose) and 613.9 ± 105.8 nmol (17.2 ± 3.0% dose), respectively. The lymphatic absorption of αTP was correlated with the amounts of PL (r = 0.77, P < 0.05) released into the mesenteric lymph. The hourly outputs of phospholipid and oleic acid also were significantly lower in LZ rats than in PF rats up to 4 h (P < 0.05). The cumulative lymphatic outputs of phospholipid (PL) were 20.1 ± 3.7 μmol/8 h in LZ and 27.0 ± 3.9 μmol/8 h in PF rats (P < 0.05). These results show that the intestinal absorption of vitamin E is affected by the zinc status of rats. This observation along with our earlier finding of a lower intestinal absorption of retinol suggests that zinc nutriture has a profound effect on the intestinal absorption and body status of lipid soluble vitamins.

Frusemide in pulmonary oedema: continuous versus intermittent

Objective: To analyse and compare the infusion of frusemide by different modes of administration. Design: Prospective clinical survey of patients suffering from acute respiratory failure due to cardiogenic pulmonary oedema. Setting: A seven-bed general intensive care unit. Patients: Group A comprised 10 patients treated with intravenous frusemide several times daily at a dose of 1 mg/kg. Group B comprised 10 patients treated with continuous infusion of frusemide for 24 hours at an initial dose of 1 mg/kg, and 0.1 mg/kg/hr thereafter, with an option of increasing the dose every 2 hours. Group C comprised 10 patients treated with albumin and frusemide combined in continuous infusion over 24 hours at a dose of 250 mg frusemide diluted in 12.5 g albumin at a rate of 0.1 mg frusemide/kg/hr. Measurements: i) Serum electrolytes, creatinine, blood urea nitrogen (BUN) and protein; ii) urinary electrolytes; iii) hourly urinary output during the first 24 hours after admission. Results: There were no differences in the total dose of frusemide between the three groups. Urinary output of Group B was significantly greater than Groups A or C. There was less variability in hourly urinary output compared with the other groups. There was no significant difference in urinary electrolyte excretion among the three groups. Conclusion: The continuous infusion of frusemide in patients with cardiogenic pulmonary oedema results in less variability of hourly urinary output, and is much easier to administer compared with the bolus dosing method. Steady urinary output is particularly advantageous in haemodynamically labile patients, and may thus be the preferred method of frusemide administration.

The lymphatic absorption of lipids is normalized by enteral phosphatidylcholine infusion in ovariectomized rats with estrogen replacement

Estrogen (ES) replacement previously was shown to decrease the lymphatic absorption of fat with a simultaneous decrease in phospholipid (PL) output in ovariectomized (OX) rats. The present study was conducted to investigate whether intraduodenal infusion of phosphatidylcholine (PC) would normalize the absorption of 14C-linoleic acid ( 14C-LA) and unlabeled oleic acid (OA) in OX rats implanted s.c. with an estradiol pellet (OXE; 25 μg/day/rat), compared with OX rats implanted with a placebo pellet (OXP). Additionally, this study examined whether ES would alter the rate of fatty acid esterification into various lipids in the intestinal mucosa. Both groups were meal-trained and pair-fed for 7 weeks. Each rat with a lymph cannula was infused at 3 mL/hr via a duodenal catheter with a lipid emulsion containing 14C-LA and triolein (380 μmol) with or without PC (41 μmol). Lymph was collected hourly for 8 hr via a lymph fistula. Without PC infusion, the total lymphatic absorption of 14C-LA was significantly lower (26.0 ± 3.4% dose) in OXE rats than in OXP rats (31.8 ± 2.0% dose) with a close parallel decrease in OA output at 2 hr and thereafter. Also, the total lymphatic secretion of PL was significantly lower in OXE rats (26.5 ± 2.4 μmol) compared with OXP rats (37.1 ± 4.1 μmol). When PC was infused, the total lymphatic absorption of 14C-LA and OA in OXE rats was restored completely to normal, whereas PC infusion had no effect on the lymphatic outputs of 14C-LA or OA in OXP rats. The lymphatic outputs of PL were enhanced markedly in both groups with PC infusion. The hourly output of PL was correlated highly with the absorption of 14C-LA ( r = 0.81) and OA ( r = 0.78). Regardless of whether lysophosphatidylcholine (lysoPC) was present in the intestinal lumen, the rates of mucosal 14C-LA incorporation into triglycerides (TG), PL, and other lipids were not affected by ES treatment. The results indicate that the slower rate of lymphatic absorption of fatty acids in ES-treated rats is not due to alteration in mucosal fatty-acid esterification, but to a limited availability of PL to the enterocyte. This may be associated with an inhibitory effect of ES on the hepatic secretion of PL via the biliary route.

Calculation of the hourly output of a solar still for various cities in Iran

An empirical method for calculation of the hourly output of a basin-type solar still over a 24-hour cycle for nine city locations in Iran has been studied. The hourly performance of the solar still is computed for each month of the year given the values of insolation for the location considered, the local ambient temperature, wind heat transfer coefficient, base and side heat transfer coefficient, water depth and a new variable called the service time. Based on the daily output, the suitability of the basin-type solar still design for providing drinking water in a number of communities in various locations in Iran is demonstrated.

Calculation of Hourly Output of a Solar Still

An approximate method for calculation of the hourly output of a solar still over a 24-hour cycle has been studied. The hourly performance of a solar still is predicted given the values of the insolation, ambient temperature, wind heat-transfer coefficient, water depth, and the heat-transfer coefficient through base and sides. The proposed method does not require graphical constructions and does not assume constant heat-transfer coefficients as in the previous methods. The possibility of using the values of the heat-transfer coefficients for the preceding time interval in the heat balance equations is examined. In fact, two variants of the basic method of calculation are examined. The hourly rate of evaporation is obtained. The results are compared to those obtained by numerical solution of the complete set of heat balance equations. The errors from the approximate method in prediction of the 24-hour output are within ±1.5 percent of the values from the numerical solution using the heat balance equations. The range of variables covered is 5 to 15 cms in water depth, 0 to 3 W/m2K in a heat-transfer coefficient through base and sides, and 5 to 40 W/m2K in a wind heat-transfer coefficient.

Burn shock resuscitation.

The goal of fluid resuscitation in the burn patient is maintenance of vital organ function at the least immediate or delayed physiological cost. To optimize fluid resuscitation in severely burned patients, the amount of fluid should be just enough to maintain vital organ function without producing iatrogenic pathological changes. The composition of the resuscitation fluid in the first 24 hours postburn probably makes very little difference; however, it should be individualized to the particular patient. The utilization of the advantages of hypertonic, crystalloid, and colloid solutions at various times postburn will minimize the amount of edema formation. The rate of administration of resuscitation fluids should be that necessary to maintain satisfactory organ function, with maintenance of hourly urine outputs of 30 cc to 50 cc in adults and 1-2 cc/kg/% burn in children. When a child reaches 30 kg to 50 kg in weight, the urine output should be maintained at the adult level. With our current knowledge of the massive fluid shifts and vascular changes that occur, mortality related to burn-induced hypovolemia has decreased considerably. The failure rate for adequate initial volume restoration is less than 5% even for patients with burns of more than 85% of the total body surface area. These improved statistics, however, are derived from experience in burn centers, where there is substantial knowledge of the pathophysiology of burn injury. Inadequate volume replacement in major burns is, unfortunately, common when clinicians lack sufficient knowledge in this area.

Effects of Enteral Fat Emulsion on Fat Absorption in Obstructive Jaundiced Rats

The effects of fat emulsion given enterally on fat absorption were studied with obstructive jaundiced rats (J group) as compared with jaundice-free rats (C group). The J and C groups were subdivided into JE and CE groups using emulsified fat for the fat absorption test, and JU and CU groups using unemulsified fat. Rats in all groups were fed for 7 days with regular rat chow. After fasting for 12 hours, 14C-labeled fat emulsion was infused to the JE and CE, and 14C-labeled unemulsified fat to the JU and CU groups through a gastrostomy for the absorption test. The hourly and cumulative output of 14CO2 by respiration, absorption rate of 14C-labeled fat in the intestine, and metabolic oxidation rate of the absorbed fat were determined during an 8-hour period after the gastroenteral administration of emulsified or unemulsified fat. The peak of hourly output was seen after the first 2 hours in the CE, JE, and CU groups, following which a remarkable decline was seen in the CE and CU groups. However, a more gentle descent in the JE, and fluctuation at a low level in the JU group were observed. The cumulative output in the JE was 61% of that in the CE, while the output in the JU was 16% of that in the CU group. The absorption rate in the JE was 81% of that in the CE group, while the rate in the JU was 22% of that in the Cu group.(ABSTRACT TRUNCATED AT 250 WORDS)

Time, Salary, and Incentive Payoffs in Labor Contracts

Time (hourly payoffs) and salary (the payoff does not vary with hours) account for the bulk of the payoffs on labor contracts. This article argues that the choice between time and salary centers on the presence (time) or absence (salary) of information about flows of effort or output per unit time. Without information about the flow of hourly effort or output, payoffs for time give the worker an incentive to supply hours without effort. Time can then become uninformative about output. In this situation, if the contract includes a fixed payoff, it is likely to be a salary rather than a payoff for time.

Norepinephrine: A potent activator of glycogenolysis and gluconeogenesis in rockfish hepatocytes

Norepinephrine (NOR) is a potent activator of carbohydrate metabolism in isolated hepatocytes from copper rockfish ( Sebastes caurinus), increasing rates of glycogenolysis fourfold with an EC 50 of 6.3 n M. Nanomolar concentrations of NOR also enhance gluconeogenesis. Epinephrine (EPI) activates both pathways to a smaller extent; the corresponding EC 50 for glycogenolysis is 320 n M. There is no significant difference between the magnitude of glucose production in response to comparable doses of NOR, bovine glucagon, and catfish glucagon-like peptide. Experiments with an adrenergic agonist (isoproterenol) and antagonists (propranolol, prazosin, atenolol) indicate that NOR effects are mediated through β-adrenoceptors. Catecholamine-activated glycogenolysis measured at 100 n M EPI or NOR is poorly correlated with a 30–50% rise in intracellular cAMP. Glucose production following catecholamine administration is not linear: 50% of the hourly glucose output is released within the first 17 min (NOR) and 5 min (EPI), respectively. During hepatocyte incubation (60 min at 15°), added NOR and EPI (100 n M) were not degraded to any significant extent. In the absence of added hormones, rockfish hepatocytes produce 7.41 ± 0.89 μmol glucose × g −1 packed cells × hr −1 at 15°, with gluconeogenesis accounting for 35.0% of the total production. The rate of glucose output, which is linear for at least 60 min, is not correlated with the initial hepatocyte glycogen level.

A New Liver Perfusion and Preservation System for Transplantation Research in Large Animals

A kidney perfusion machine, model MOX-100 (Waters Instruments, Ltd, Rochester, MN) was modified to allow continuous perfusion of the portal vein and pulsatile perfusion of the hepatic artery of the liver. Additional apparatus consists of a cooling system, a membrane oxygenator, a filter for foreign bodies, and bubble traps. This system not only allows hypothermic perfusion preservation of the liver graft, but furthermore enables investigation of ex vivo simulation of various circulatory circumstances in which physiological perfusion of the liver is studied. We have used this system to evaluate the viability of liver allografts preserved by cold storage. The liver was placed on the perfusion system and perfused with blood with a hematocrit of approximately 20%, and maintained at 37 degrees C for 3 h. The flows of the hepatic artery and portal vein were adjusted to 0.33 mL and 0.67 mL/g of liver tissue, respectively. Parameters of viability consisted of hourly bile output, oxygen consumption, liver enzymes, electrolytes, vascular resistance, and liver histology. This method of liver assessment in large animals will allow the objective evaluation of organ viability for transplantation and thereby improve the outcome of organ transplantation. Furthermore, this pump enables investigation into the pathophysiology of liver ischemia and preservation.

Hemodynamics and blood volume in angiotensin II salt-dependent hypertension in dogs

The sequential effects of an increased daily NaCl intake on hemodynamics, fluid electrolyte balances, and hormonal responses were evaluated in dogs (n = 7) with fixed circulating levels of angiotensin II (ANG II). During the control period, ANG II was infused at 3 ng.kg-1.min-1 while dogs were maintained on an 8 meq NaCl/day diet. Water intake was fixed at 700 ml/day. Continuously recorded (24 h/day) changes of total body weight (TBW) were used as an index of total body water. Cardiac stroke volume and arterial pressure were recorded, and each beat was digitized to provide hourly and 24-h average cardiac output (CO), mean arterial pressure (MAP), and total peripheral resistance (TPR). After three stable control days, daily salt intake was increased to 120 meq for 7 days. TBW increased gradually to 448 +/- 111 g (2.9%, P less than 0.05) above control by day 3. An 11% expansion of blood volume (P less than 0.05) was found (51CR-labeled red blood cells) on day 2 of high NaCl. CO rose 12% and MAP 20% (P less than 0.05) in parallel with TBW by day 4. By day 7, CO remained only 5% elevated, whereas MAP had stabilized at 20% above control levels. TPR remained significantly elevated from days 3 through 7. A positive Na balance averaging 91 +/- 8 meq (P less than 0.05) occurred on day 1. Plasma Na concentration was increased 2-3 meq/l above control throughout the period of high-salt intake. Plasma renin activity and aldosterone levels decreased to nearly undetectable levels, vasopressin rose slightly, and atrial natriuretic peptide levels increased significantly. Dogs maintained at 8 meq/day NaCl during the same infusion of ANG II showed no changes in MAP, CO, TPR, or TBW. In summary, the salt-induced hypertension was consistently related to small but significant fluid retention, blood volume expansion, elevations of cardiac output, and a gradual increase in TPR.

Resuscitation and fluid balance

Summary Salt and water are the essential requirements for effective resuscitation of a patient with extensive burns. The optimum sodium load is of the order of 0.5 mmol/kg body weight/% burn, and the total volume of fluid (excluding the replacement of any large evaporative losses) is likely to be between 2 and 4 ml/kg body weight/% burn. Sodium-free water, given to replace any extrarenal losses, should be limited to an amount sufficient to prevent marked hypernatraemia. The priorities in practical management are the establishment of a reliable intravenous line and the planned administration of a suitable salt-containing fluid, with the aim of maintaining vital organ function at the least immediate or delayed physiological cost. The effectiveness of the fluid therapy in correcting existing deficits and in keeping pace with continuing losses should be reviewed at frequent intervals, bearing in mind that the rate of loss decreases with time. Usually, at least one half of the total fluid requirement will have been given in the first 12h, and periodic adjustments to the rate of infusion should be made in response to information gained by monitoring the patient's condition. Urine produced during the first 24h following extensive burns is usually concentrated, i.e. osmolarity between 500 and 1000 mOsm/l and water diuresis, i.e. osmolarity less than 300 mOsm/l, is rare. An hourly output of between 0.5 and 1.0 ml/kg body weight (using 12.5 kg as a minimum weight for infants) of concentrated urine is a useful index of satisfactory resuscitation; less than 0.5 ml/kg/h indicates undertransfusion, while an output well over 1.0 ml/kg/h suggests overtransfusion. The hallmark of renal failure is severe tubular impairment that results in loss of concentrating power. If there is severe glomerular impairment as well, oliguria will be evident; otherwise the urine volume may be normal. Hence the importance of measuring urine concentration (osmolarity) or calculating the urine/blood urea ratio, which in normal health is usually 50 or more but in acute renal failure is less than 5. The triad of oliguria, loss of urine concentration and haem pigments in the urine is particularly ominous. A forced solute diuresis should be attempted (intravenous mannitol, 1 g/kg body weight as a 15 or 20% solution) whenever obvious ‘haemoglobinuria' occurs, but should not be repeated if a marked diuresis does not ensue. When examination of the urine output indicates serious renal impairment, the advice of a renal specialist should be obtained without delay. The enormous positive fluid balance typically present at 48 h postburn will, in the absence of effective renal function, threaten the patient's life by pulmonary oedema long before he is at risk of dying from uraemia.

Circadian Rhythm of Gastric Acid Secretion in Active Duodenal Ulcer: Chronobiological Statistical Characteristics and Comparison of Acid Secretory and Plasma Gastrin Patterns with Healthy Subjects and Post-Vagotomy and Pyloroplasty Patients

Twenty-one male patients with active duodenal ulcer underwent hourly 24-hr gastric acid collections under controlled, calorically deprived conditions. The 24-hr hourly acid secretory output for the group displayed a statistically significant (p less than 0.001) rhythm, with peak rates occurring during the evening hours and low rates during the early morning hours, by population-mean cosinor statistical analysis. Population-mean cosinor analysis also verified the occurrence of a significant (p = 0.034) circadian rhythm in unstimulated acid secretion in a group (N = 14) of healthy male subjects similarly studied and reported previously. In contrast, population-mean cosinor analysis confirmed the absence of any detectable circadian rhythm in unstimulated acid secretion in a group (N = 17) of postvagotomy and pyloroplasty patients studied 2-11 years after surgery. Population-mean cosinor analysis of 4-hr plasma gastrin determinations, obtained in all groups during the 24-hr gastric acid collection, revealed an absence of any detectable circadian rhythm in plasma gastrin. This latter finding is compatible with the interpretation that the circadian rhythm of unstimulated gastric acid secretion, observed in the clinically healthy and active ulcer groups, is unrelated to changes in plasma gastrin levels. The employment of quantitative chronobiological inferential statistical techniques is important to the analysis of any time-dependent measurement in gastrointestinal function, of which gastric acidity is one example.