Effects of nitroprusside and ketanserin upon pulmonary edema after acid injury

Increased hydrostatic pressure and microvascular permeability after acid aspiration as causes of pulmonary and tracheobronchial edema were studied. Eighteen dogs were anesthetized and 3.0 milliliters per kilogram of 0.1 normal hydrochloride instilled into the trachea. After one hour, the platelet count decreased 47,500 per cubic millimeter (p less than 0.05) from base line levels of 221,400 per cubic millimeter and platelet serotonin stores decreased from 2.09 to 1.65 micrograms per 10(9) platelets (p less than 0.05). Mean pulmonary arterial pressure increased progressively from a base line value of 11 to 21 millimeters of mercury four hours after acid instillation (p less than 0.05). Mean arterial pressure fluctuated from a high of 143 millimeters of mercury to the final value, at four hours, of 119 millimeters of mercury. Ketanserin, a serotonin receptor antagonist, infused one hour after acid injury did not prevent release of platelet 5 hydroxytryptamine but led to a 24 per cent decrease in mean pulmonary arterial pressure from 13 to 10 millimeters of mercury (p less than 0.05) and an 11 per cent decrease in mean arterial pressure from 135 to 120 millimeters of mercury (p less than 0.05). Nitroprusside produced a 30 per cent decrease in mean arterial pressure, but only a 20 per cent decline in mean pulmonary arterial pressure (p less than 0.05). Four hours after acid was instilled, untreated dogs produced 129 milliliters of edema fluid from the endotracheal tube. In proportion to the relative decline in mean pulmonary arterial pressure, nitroprusside therapy reduced the volume of edema to 72 milliliters (p less than 0.05) and ketanserin to 52 milliliters (p less than 0.05). These results suggest that 5 hydroxytryptamine contributes to the pulmonary hypertension associated with acid injury and that the volume of edema formed may be directly related to the increase in the hydrostatic pressure.     

Pulmonary and systemic consequences of localized acid aspiration

Acid aspiration may recruit a generalized inflammatory reaction that can potentiate the local injury. After surgical isolation of bronchi in a group of 15 dogs, 1 milliliter per kilogram of 0.37 normal hydrochloric acid was instilled into either side. After five minutes, platelet and white blood cell counts fell to 10,000 and 1,000 per cubic millimeter (p less than 0.05). Platelet aggregates were noted in blood smears. 111Indium-platelet activity doubled over both the aspirated and nonaspirated lung (p less than 0.05). Physiologic dead space rose from 18 to 67 per cent and to 46 per cent in the aspirated and nonaspirated lung (p less than 0.05). Physiologic shunt increased from 12 to 47 per cent and to 43 per cent (p less than 0.05) on the two sides. Plasma thromboxane B2 levels at 30 minutes rose from 0.28 to 0.93 nanograms per milliliter (p less than 0.05). Edema fluid from the aspirated lung had thromboxane B2 values of 2.87 nanograms per milliliter, indicating pulmonary synthesis. Within five minutes of aspiration, systemic effects were prominent; mean arterial pressure fell from 114 to 46 milliliters of mercury (p less than 0.05), and the cardiac index fell 24 per cent from 106 to 81 milliliters per kilogram per minute (p less than 0.05) along with an 18 per cent decrease in contractility of a rat papillary muscle bathed in plasma from the aspirated dog. Mean pulmonary arterial pressure rose from 12 to 18 millimeters of mercury (p less than 0.05). Despite fluid infusion at 36 milliliters per kilogram per hour to keep wedge pressure constant at 5.5 millimeters of mercury, and sampling of one-third the blood volume, hemoglobin concentration rose 0.9 grams per cent (p less than 0.05) indicating increased microvascular permeability. At autopsy, the aspirated and nonaspirated lung were indistinguishable with congestion, interstitial hemorrhage, and white blood cell infiltrates. Systemic organs showed vascular congestion and edema. These data demonstrate that local aspiration leads to generalized inflammatory sequelae with cardiopulmonary failure.     

The effect of a mechanical venous pump on the circulation of the feet in the presence of arterial obstruction

A boot of single layer, flexible vinyl sheeting and a pneumatic cuff encircling its top at the ankle, each independently inflatable, constitute a mechanical venous pump. Inflation of the cuff to the desired boot pressure is followed immediately by inflation of the boot from a reservoir with higher available pressure than that in the cuff. When the boot pressure reaches cuff pressure, the excess air escapes from the boot under the cuff. A low venous pressure at the foot could be maintained by compressing the foot for 2 seconds every 15 seconds with a pressure which is 10 millimeters of mercury above initial venous pressure. In seated patients with arterial obstruction whose supine ankle blood pressure was 60 milimeters of mercury or less, the rate of blood flow in the skin of the forefoot was increased by 104.1 +/- 43.7 per cent S.E.M., p less than 0.05, during venous pumping. In these patients, a change in posture alone from supine to sitting increased the rate of blood flow by 81.7 +/- 19.47 per cent, p less than 0.002. The combined effect of the erect posture and venous pumping was an increase of 185.7 +/- 49.63 per cent, p less than 0.01. Rest pain was relieved by the combined effect.     

Physiologic changes of antishock trousers in relationship to external pressure

The results of this study on dogs demonstrates that 60 millimeters of mercury counterpressure does not differ significantly from 100 millimeters of mercury counterpressure either in the increase in carotic pressure or in the mobilization of blood in the lower extremities and abdomen. Therefore, one could assume that vital organ perfusion is just as effective at 60 millimeters of mercury as at 100 millimeters of mercury. Sixty millimeters of mercury counterpressure produces less lactic acidosis and hyperkalemia than does 100 millimeters of mercury. It must be emphasized, however, that the blood pressure of the dogs was maintained at 80 millimeters of mercury, significantly below the 100 millimeters of mercury of the counterpressure. The results of previous studies have demonstrated that, when the blood pressure in animals is maintained at 100 millimeters of mercury, this metabolic acidosis and hyperkalemia are not as severe. Data from these experiments demonstrated that, when the blood pressure in animals is maintained at 120 grams and the external counterpressure is maintained at 100 millimeters, there is only a minimal to moderate accumulation of lactic acid and potassium. It can be inferred, therefore, that, when blood pressure is returned to within normal range, there is enough perfusion of the lower extremities and abdomen to prevent production of excessive lactic acid and potassium. Finally, the results of the present study demonstrated that a significant amount (up to 30 per cent of blood volume) is mobilized from the lower extremities and abdomen when the device is properly applied.     

Control of bleeding is essential for a successful treatment of hemorrhagic shock with 7.5 per cent sodium chloride solution

Small volume hypertonic saline (HTS) solution resuscitation has been shown to restore hemodynamic derangements and to protect against mortality in "controlled" hemorrhagic shock (CHS), but it exacerbates the shock state in "uncontrolled" hemorrhagic shock (UCHS). To study the mechanisms associated with the divergent outcome of HTS treatment in CHS versus UCHS, HTS was administered to anesthetized rats (n = 7) subjected to 15 per cent resection of the tail followed by controlled or uncontrolled bleeding. HTS treatment of UCHS increased bleeding (13.3 +/- 1.6 milliliters, p less than 0.05), dropped mean arterial pressure (MAP) (-84.5 +/- 8.9 millimeters of mercury, p less than 0.001), central venous pressure (zero millimeters of mercury, p less than 0.001) and cardiac index (CI) (41 per cent of basal value, p less than 0.001) and increased acidosis (pH 7.23 +/- 0.12, p less than 0.05) and mortality (mean survival time 75 +/- 15 minutes versus 122 +/- 23 minutes of untreated rats, p less than 0.05). In contrast, when administered after application of a ligature proximal to the resection site (at 15 minutes), HTS completely reversed the changes in MAP, CI and total peripheral resistance index (TPRI), and improved mean survival time (172 +/- 7 minutes, p less than 0.05). These data support the assumption that HTS should be used in the treatment of hemorrhagic shock only after bleeding was controlled.     

Limb salvage and selectivity.

In a group of properly prepared poor risk patients with advanced atherosclerosis of both the aortoiliac and femoropopliteal segments, a combined procedure, extra-anatomic bypass with an extended profundoplasty, was used for successful salvage of their ischemic--mean calf pressure=27 millimeters of mercury--limbs. Prediction of success versus failure could be determined on neither clinical nor angiographic-anatomic grounds but was possible using two simple measurements: a large aortoiliac differential pressure--deltaP--between inflow pressure obtained from a standard arm cuff and outflow pressure measured directly from the femoral artery, 89.3 millimeters of mercury versus 33.2 millimeters of mercury, p less than 0.001, and a potentially adequate outflow bed as determined by the percentage drop in outflow [(deltaPo/Po) per cent] upon papaverine injection, 36.3 versus 11.3 per cent, p less than 0.001. These values became an important part of the selection scheme developed in the approach to 24 ischemic limbs.     

Physiologic monitoring goals for the critically ill patient.

Definition of the appropriate therapeutic goals for physiologic monitoring of patients postoperatively was approached by analyzing more than 50,000 values of the 20 most commonly monitored variables in a series of 113 critically ill patients throughout their immediate postoperative course. In general, normal values were poor criteria for monitoring, since normal values were restored in an average of 75 per cent of the survivors and 76 per cent of the nonsurvivors for the five most frequently measured variables; that is, arterial pressure, heart rate, central venous pressure, wedge pressure and cardiac output. Moreover, an average of 56 per cent of the 20 most commonly monitored variables of nonsurvivors was restored to the normal range. Furthermore, 34 per cent of all the nonsurvivors' values were within the normal range; this was only 2.4 per cent less than the percentage of normal values for the survivors. The empirically determined median value of the survivors taken in the late stage during periods remote from therapy was found to be a better criterion for therapeutic goals for most variables, including blood flow, oxygen transport and most intravascular pressures. However, normal values were satisfactory for arterial pressure, peripheral resistance, pH, mixed venous oxygen tension and arterial carbon dioxide tension, largely because of the biphasic patterns of these variables.     

Simultaneous measurement of hepatic arterial and portal venous flows by transit time ultrasonic volume flowmetry

Simultaneous measurement of the hepatic artery and the portal vein was performed successfully upon 15 anesthetized patients during abdominal operations with the use of transit time ultrasonic volume flowmeter. The hepatic arterial flow, portal venous flow and total hepatic flow were 267.3 +/- 21.2, 746.4 +/- 41.3 and 1,010.7 +/- 52.7 milliliters per minute, respectively. The ratio of hepatic arterial flow to portal venous flow was 0.36 +/- 0.03. Temporary occlusion of the portal vein resulted in a significant increase in hepatic arterial flow (23.6 +/- 4.3 per cent, p less than 0.01), whereas temporary occlusion of the hepatic artery did not alter portal venous flow significantly. Occlusion of the common hepatic artery induced a significant decrease in hepatic arterial flow (p less than 0.05), but did not alter portal venous flow significantly. The results of this approach had useful clinical meanings in one patient in whom the Appleby's operation was performed in which sufficient hepatic arterial flow was needed after the common hepatic artery was ligated. Data are presented for hepatic circulation measured by transit time ultrasonic volume flowmeter, which is a good device to use to assess portal venous flow as well as hepatic arterial flow with reproducibility and stability.     

Role of volume expansion in severe pre-eclampsia

Fifteen primigravid patients with severe pregnancy-induced hypertension were studied by catheterization of the right side of the heart. A hemodynamic protocol was implemented that required maintaining colloid osmotic pressure above 17 millimeters of mercury, pulmonary capillary wedge pressure below 15 millimeters of mercury and the mean arterial pressure in a very narrow range throughout labor and delivery and for 48 hours postpartum. The initial colloid osmotic pressures and pulmonary capillary wedge pressures were 18.0 +/- 2.6 and 10.5 +/- 4.0 millimeters of mercury, respectively, and remained essentially unchanged throughout the post partum period. The only benefit derived from volume expansion in these patients appeared to be the absence of acute fetal distress after the initiation of antihypertensive therapy. Six of 15 patients had late fetal stress develop during labor, suggesting that aggressive volume repletion and colloid osmotic pressure correction in pregnancy-induced hypertension does not effect the over-all incidence of fetal distress. We recommend that correction of colloid osmotic pressure be restricted to instances in which extremely low values (less than 12 millimeters of mercury) or a prolonged negative colloid osmotic pressure to pulmonary capillary wedge pressure gradient are identified. Finally, the benefit of volume expansion in pregnancy-induced hypertension appears to be the prevention of sudden and profound drops in blood pressure with antihypertensive therapy--not the prevention of fetal distress during labor.     

Follow-up evaluation of venous morphologic factors and function after thrombectomy and temporary arteriovenous fistula in thrombosis of iliofemoral vein

Fifty-seven patients (58 post-thrombotic legs) treated with venous thrombectomy and temporary arteriovenous fistula for thrombosis of the iliofemoral vein were evaluated in a follow-up study regarding clinical, morphologic and functional aspects nine to ten months after thrombectomy. There were 33 men and 24 women, between 15 and 84 years of age (a mean of 51 years). The results of clinical examination revealed that 75 per cent of the patients had a good and 20 per cent a fair result of the treatment. No ulcers of the leg or venous claudication had developed. Venography (53 legs) demonstrated 61 per cent patency rate of the iliofemoral segment, although post-thrombotic changes were noted in 23 per cent. Venous femoral pressure measurement was normal in 82 per cent of 28 legs examined despite some proximal stenosis or occlusion. A good venous emptying with plethysmography was achieved in 29 per cent and foot volumetry showed normal peripheral venous function in 29 per cent. The results of this follow-up study, however short, reveal that venous patency can be restored to a high extent with good clinical result. Functionally, these patients may be at high risk for having sequelae develop later.     

Hepatic blood flow and oxygen consumption in starvation, sepsis and septic shock.

Total hepatic and portal blood flow as well as hepatic and splanchnic oxygen consumption was measured in pigs in the normal fasted state and in the septic fasted state induced experimentally by cecal ligation. Pigs in the septic state were divided into two groupds, a septic high output state and a septic low output state, according to whether or not a pig showed a higher or lower cardiac output in the septic state than in the normal fasted state. In the septic high output state, the average cardiac output was 155 per cent of that during fasting; hepatic arterial flow increased 96 per cent, while portal flow decreased 19 per cent. Total hepatic blood flow increased slightly, 14 per cent. The ratio of total hepatic blood flow to cardiac output decreased from 42 per cent in the normal fasted state to 30 per cent. The total hepatic oxygen consumption increased 26 per cent because of significantly elevated oxygen transport by hepatic arterial flow. In the low output state, hepatic arterial flow significantly dropped, 74 per cent, while portal flow decreased slightly, 23 per cent, and total hepatic blood flow decreased 38 per cent. The decrease of cardiac output was less, 18 per cent. The ratio of total hepatic blood flow to cardiac output was 31 per cent. Total hepatic oxygen consumption decreased remarkably, 29.1 per cent, due chiefly to the decrease of hepatic arterial flow, and splanchnic oxygen consumption also decreased significantly, 22 per cent. Dissociation of hepatic arterial response to sepsis from the other gastrointestianl vessels caused a great difference in the hepatic oxygen consumption between the septic high output and the septic low output state, contributing in part to the difference in mortality between these two states.     

Central hemodynamics in acute gastrointestinal bleeding.

In 15 patients with acute gastrointestinal bleeding, central hemodynamics were monitored by means of a flow directed thermodilution catheter. Also, the systemic blood pressure, heart rate, blood volume and oxygen saturation in arterial and mixed venous blood were measured. In patients without cardiac insufficiency, the pulmonary artery mean pressure was found to be the hemodynamic parameter giving the most clear and constant evidence of hypovolemia. In patients with left ventricular failure and hypovolemia, the pulmonary artery pressures revealed cardiac insufficiency, and the central venous pressure indicated the degree of hypovolemia. The method has proved useful in observing patients with acute gastrointestinal hemorrhage complicated by cardiac disease, cirrhosis of the liver or the frailty of old age.     

Skin microvascular permeability after resuscitation with Ringer's lactate solution from endotoxin shock

Skin microvascular membrane permeability was assessed in anesthetized dogs after resuscitation from endotoxin shock. Infusion of Ringer's lactate solution, in a volume equal to 7 per cent of the body weight, reversed hypotension produced by an intravenous injection of Escherichia coli endotoxin (0.5 milligrams per kilogram). The shock group was compared with a group of dogs not given endotoxin and infused with a similar dose of Ringer's lactate solution and a with control group of dogs. Prenodal lymph was collected from both hindpaws and three to four hours before ending an increase of 20 to 28 millimeters of mercury in venous pressure of the hindpaw was produced in one limb by tightening a tourniquet. This maneuver produced an increase in lymph flow associated with an increase in lymph protein flux that was similar in all three groups. The wet to dry tissue weight ratio of skin samples did not increase in the endotoxin group. Skin microvascular membrane permeability did not increase. The safety factors that helped to prevent edema after infusion of Ringer's lactate solution included an increase in lymph flow and sieving by the intact microvascular membrane which diluted the interstitial protein concentration.     

Postoperative renal dysfunction can be predicted

The two prior hypotheses of the study were that, among a high risk population of patients who were hypertensive, who had diabetes and who underwent elective general surgical treatment, the duration of intraoperative hypotension and hypertension (greater than 20 millimeters of mercury above or below the preoperative base line) and intraoperative administration of less than 300 milliliters per hour of saline solution containing fluids would identify patients at higher risk for postoperative renal dysfunction. Among those who had an intraoperative mean arterial pressure (MAP) that fell more than 20 millimeters of mercury below the base line, 15 per cent of those with fall of MAP lasting for greater than or equal to 60 minutes had postoperative renal dysfunction, whereas those with drops in pressure lasting for less than 60 minutes did not sustain increased postoperative renal dysfunction. Patients who had intraoperative MAP rise to greater than 20 millimeters of mercury above the preoperative base line value for greater than 30 minutes also had twice the rate of postoperative renal dysfunction. Fifteen per cent of the patients who received less than 300 milliliters per hour of isotonic saline-like fluids had postoperative renal dysfunction, significantly more than the 8 per cent of those who received greater than or equal to 300 milliliters per hour. Two intraoperative events also significantly increased postoperative renal dysfunction rates: cardiac arrest and the drainage of massive ascites. Patients with decompensated congestive heart failure at admission to the hospital had significantly increased postoperative renal dysfunction; these patients and probably should not undergo an operation unless it is an emergency. All of the patients, regardless of the magnitude of the operation and of its projected length or type of anesthesia, should be given greater than 300 milliliters per hour of isotonic saline-like solutions.     

A comparison of general versus local anesthesia during inguinal herniorrhaphy.

The current study was done to compare the hemodynamic changes, recovery events and economic impact of elective inguinal herniorrhaphy performed with general anesthesia (GA) or regional field block (RB) in 20 patients (American Society of Anesthesiology class I). In the GA group, anesthesia was induced with thiopental and the trachea was intubated after intravenous administration of 0.08 milligrams per kilogram of vecuronium. GA was maintained with 1.2 +/- 0.25 per cent enflurane in 50 per cent nitrous oxide and oxygen, and ventilation was controlled to keep PECO2 at 36 +/- 2 millimeters of mercury. Anesthesia in the RB group was accomplished by local injection of 3.5 +/- 0.5 milligrams per kilogram of 0.5 per cent bupivacaine. In each patient, a suprasternal ultrasonic Doppler probe was used to measure cardiac output before induction of anesthesia, during and after operation. Total peripheral resistance was calculated from mean arterial pressure and cardiac output. There were no statistically significant differences between cardiac output, mean arterial pressure, total peripheral resistance and heart rate in the two groups at any time period during the study. Patients in the RB group did not require parenteral medication for relief of postoperative pain, whereas all those in the GA group did. Significant cost benefits were realized by the RB group because of elimination of general anesthetic and reduction of recovery room fees.     

Long term results of treatment of Budd-Chiari syndrome by side to side portacaval shunt

This is a report of a long term prospective study of 13 seriously ill patients with Budd-Chiari syndrome as a result of occlusion of the hepatic veins who were treated by side to side portacaval shunt from four to 78 weeks after the onset of symptoms and who were under observation for three to 16 years. The patient population was young, ranging in age from 19 to 45 years; seven were men and six were women. The presumed cause was the use of oral contraceptives in three, polycythemia rubra vera in two, Behcet disease in one patient and unknown in seven patients. All of the 13 patients had abdominal pain, marked ascites, hepatosplenomegaly, wasting and disturbed liver function. Diagnosis was based on the symptoms and signs: angiographic demonstration of hepatic vein occlusion and a patent inferior vena cava; pressure measurements that showed an inferior vena caval pressure that was normal or within the usual range for patients with massive ascites and an elevated wedged hepatic vein pressure that was much higher than the inferior vena caval pressure, and the results of biopsy of the liver showing centrilobular congestion and necrosis. Side to side portacaval shunt was very effective in decompressing the liver, reducing the mean corrected portal pressure from 240 millimeters of saline solution before to 7 millimeters of saline solution after the shunt. Operative survival rate was 92 per cent, and the long term survival rate for three to 16 years is 85 per cent. All of the survivors are free of ascites without requiring diuretic therapy.(ABSTRACT TRUNCATED AT 250 WORDS)     

Immediate preoperative phlebotomy with autologous blood donation for aortic replacement

The preferential use of autologous blood provided by phlebotomy can reduce the need for homologous blood transfusion in patients undergoing extensive elective operations. This blood is usually provided either by intraoperative isovolemic hemodilution or phlebotomy one to two weeks preoperatively. To minimize the intraoperative time delay or preoperative period between phlebotomy and operation required in these patients, we performed preoperative isovolemic hemodilution in 69 patients one to two days prior to elective aortic replacement for infrarenal aneurysmal disease. Patients underwent phlebotomy a mean of 0.57 +/- 0.01 liter of whole blood; volume was replaced with lactated Ringer's solution. Hematocrit levels decreased from a mean value of 42.9 +/- 0.4 per cent to 33.7 +/- 0.3 per cent. Mean intraoperative blood loss was 1.2 +/- 0.05 liters. Hemodynamic parameters (blood pressure, cardiac output, pulmonary capillary wedge pressure, central venous pressure, oxygen delivery and systemic vascular resistance) remained stable throughout the perioperative and intraoperative time periods. In addition, we evaluated the technical modification of exclusion aneurysmorrhaphy (n = 50) versus open aneurysmorraphy (n = 19) on reduction of intraoperative homologous blood transfusion in these patients. Seventy-two per cent (36 of 50) of patients whose aneurysms were excluded received no homologous blood intraoperatively. Blood loss was decreased in the excluded versus open aneurysmorraphy group, 920 +/- 90 milliliters versus 2,030 +/- 250 milliliters, as were homologous blood transfusion requirements, 175 +/- 35 milliliters versus 570 +/- 119 milliliters. Two patients died (2.9 per cent mortality rate), and there was no increase in morbidity. Surgical treatment of large aortic aneurysms is frequently performed on an urgent basis; thus, provision of autologous blood for this operation in a short period of time may be beneficial. Isovolemic hemodilution performed during the immediate preoperative period can reduce homologous blood requirements and be safely performed without adverse effects on mortality, morbidity and myocardial performance. Exclusion aneurysmorrhaphy may further reduce dependence on homologous blood.     

Characterization of a modified, stroma-free hemoglobin solution as an oxygen-carrying plasma substitute

A new infusion solution prepared from stroma-free, crosslinked and pyridoxalated hemoglobin is described. The characteristics of which have been adapted to the functions of native, intra-erythrocyte hemoglobin. The solution contains 8.5 per cent weight per volume of glutardialdehyde modified hemoglobin with a mean molecular weight (Mn) of 200,000 Dalton. The non-crosslinked fraction constitutes 15 per cent of the total hemoglobin. The p50 of 27 torr at pH 7.4 (plasma pH) corresponds to the value for the intra-erythrocyte hemoglobin at pH 7.25. The oncotic pressure is adjusted to 28 torr by the addition of 2.5 per cent weight per volume of human albumin. The methemoglobin content is less than 5 per cent of the total hemoglobin and remains constant for one year. The relative viscosity of the 8.5 per cent hemoglobin solution is 3.0 and, thus, is lower than the viscosity of blood. The intravascular half-life was determined in chimpanzees as about 16 hours. On the basis of available data, this hemoglobin solution may be suitable for clinical use as oxygen carrying plasma substitute.     

Serendipitous diagnosis of infracardiac total anomalous pulmonary venous return by umbilical venous catheter blood gas samples.

Total anomalous pulmonary venous return (TAPVR) is a rare congenital heart defect that occurs when all four pulmonary veins connect to the systemic venous circulation. We describe a full-term male neonate who presented with cyanosis and mild tachypnea shortly after birth. One umbilical artery and the umbilical vein were catheterized, and oxygen treatment was provided. Four echocardiograms indicated severe pulmonary hypertension and were negative for any congenital heart defects. After the umbilical artery catheter was removed, high partial pressure of oxygen was detected in blood samples drawn from the umbilical venous catheter that was positioned below the diaphragm. Based on this finding, TAPVR was suspected and confirmed with angiography through a central venous catheter. The neonate underwent a successful surgical repair to correct the cardiac defect.     

The judicial use of venous duplex imaging and strain gauge plethysmography (single or combined) in the diagnosis of acute and chronic deep vein thrombosis.

Sixty-eight patients (79 limbs) with clinically suspected deep vein thrombosis were evaluated by duplex imaging, strain gauge plethysmography and venography. The diagnostic accuracies were projected over a spectrum of disease incidences ranging from 10 to 90 per cent of the population. The sensitivity, specificity, positive and negative predictive values, and over-all accuracy in detecting acute deep vein thrombosis were 90.9, 87.1, 83.3, 93.1, and 88.7 per cent, respectively, for venous duplex imaging, and 81.8, 69.6, 56.3, 88.9 and 73.5 per cent, respectively, for strain gauge plethysmography. The positive predictive value and over-all accuracy of venous duplex imaging were statistically significantly higher than that of strain gauge plethysmography. When both tests were combined and compared with venous duplex imaging alone, none of these parameters were statistically significant. For chronic deep vein thrombosis, the sensitivity, specificity, positive predictive value, negative predictive value and over-all accuracy for venous duplex imaging were 75, 86, 80, 86 and 82 per cent, respectively. Fourteen per cent had inconclusive results obtained at venous duplex imaging. When strain gauge plethysmography was combined with venous duplex imaging, the over-all accuracy was 82 per cent. As the true incidence of the disease increases, the positive accuracy differences between strain gauge plethysmography and venous duplex imaging decrease to a negligible level. We concluded that over-all, venous duplex imaging is superior. However, the strain gauge plethysmography has reasonable accuracy and may be used in places where venous duplex imaging is not available. Combined use of venous duplex imaging and strain gauge plethysmography would be helpful in patients with inconclusive results obtained at venous duplex imaging and, as the true incidence increases, the positive accuracy rate of strain gauge plethysmography becomes close to that of venous duplex imaging.