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PubMed1992

Heparin and infusion phlebitis: a prospective study.

OBJECTIVE: To determine whether heparin sodium, when added to fluids infused through a peripheral catheter, reduces some local catheter-related problems (i.e., phlebitis, catheter obstruction, and extravasation of fluid) and extends the catheter's useful life. DESIGN: Prospective, double-blind, placebo-controlled. SETTING: Internal medicine ward of a general hospital with 400 beds. PATIENTS: Eighty-one consecutive acute collaborating patients who had a venous catheter in the forearm, inserted by nurses with more than one year of professional experience. INTERVENTION: Heparin sodium 1000 units/mL or NaCl 0.9% was added to compatible infusion fluids just before they were given to the patients. The final concentration of heparin was 1 unit/mL. MEASUREMENTS: Length of time until catheters were removed and reasons for their removal. RESULTS: The heparin group had a lower rate of local catheter-related problems than the placebo group (34.3 vs. 61.5 percent, respectively, p less than 0.05; 95 percent confidence interval for the difference 4.3 to 50.1 percent). The catheter's mean life in the heparin group was longer than that of placebo group (98.9 +/- 55.2 vs. 66.2 +/- 47.2 h, respectively, p less than 0.05; 95 percent confidence interval for the difference 9.15 to 56.25 h). This effect was mainly attributable to prevention of noninflammatory catheter-related problems (e.g., obstruction, extravasation) and to a delay in the appearance of phlebitis. CONCLUSIONS: Heparin sodium, when added to infusion fluids to a final concentration of 1 unit/mL, diminishes local intravenous catheter-related problems and extends the catheter's life.

Aged↗

PubMed2000

Complications and cost associated with parenteral nutrition delivered to hospitalized patients through either subclavian or peripherally-inserted central catheters.

BACKGROUND AND AIMS: Total parenteral nutrition (TPN) is typically delivered through catheters inserted into the superior vena cava (SVC) via a subclavian or internal jugular vein approach. A peripherally-inserted central venous catheter (PICC), utilizing a cephalic or basilic venous approach, may provide a safe alternative to the standard catheter approach and, because non-physician providers can insert the PICC, may introduce a potential cost-savings to health care institutions. We sought to determine if PICC lines are safer and more cost-effective than the standard central venous catheter approach for hospitalized patients who require TPN. METHODS: One hundred and two hospitalized patients (age range, 18-88 years) who required TPN were prospectively randomized to receive therapy via a centrally-inserted subclavian catheter (n=51) or a peripherally-inserted PICC line (n=51). The primary end-point was the development of a complication requiring catheter removal. Other end-points included catheter infection and thrombophlebitis. Cost associated with insertion and maintenance of each catheter was also studied. RESULTS: Complication-free delivery rate (without the need to remove or replace the catheter) was 67% for subclavian catheters and 46% for PICC lines (P<0.05). The overall infection rate was 4.9 per 1000 catheter days and was similar for each catheter type (P=0.68). PICC lines were associated with higher rates of clinically-evident thrombophlebitis (P<0.01), difficult insertion attempts (P<0.05), and malposition on insertion (P<0.05). No catheter complications resulted in significant long-term morbity or mortality. No significant difference was noted between the two catheter types in terms of aborted insertion attempts (P=0.18), dislodgement (P=0.12), or line occlusion (P=0.25). After standardizing costs for each hospital, the direct institutional costs for insertion and maintenance of PICC lines (US$22.32+/-2.74 per day) was greater than that for subclavian lines (US$16.20+/-2.96 per day;P<0.05). CONCLUSION: PICC catheters have higher thrombophlebitis rates and are more difficult to insert into certain patients when compared to the standard subclavian approach for central venous access in hospitalized patients who require TPN. Because of this, PICCs may be less cost-effective than currently believed because of the difficulty in inserting and maintaining the catheter.

Adolescent↗

PubMed2001

Difference in time to positivity of hub-blood versus nonhub-blood cultures is not useful for the diagnosis of catheter-related bloodstream infection in critically ill patients.

OBJECTIVE: The differential time to positivity (DTTP), defined as the difference in time necessary for the blood cultures taken by a peripheral puncture and through the catheter to become positive has been suggested to be useful in differentiating between catheter-related bloodstream infection (CR-BSI) and other sources of bacteremia. A DTTP of >120 mins was found predominantly in CR-BSI. The objective of our study was to investigate whether DTTP is useful for the diagnosis of CR-BSI in a medical-surgical intensive care unit. DESIGN: Prospective clinical study. SETTING: A 60-bed medical-surgical intensive care unit of a university hospital. PATIENTS: One hundred consecutive adult patients from whom catheter(s) were to be removed for suspected CR-BSI were studied. INTERVENTION: A blood culture (using aerobic and anaerobic culture bottles) was first taken from a new puncture site. Next, a blood culture was taken through every intravascular catheter in place. MEASUREMENTS AND RESULTS: DTTP was calculated using the automated BacT/Alert blood culture system. Three patients had CR-BSI and nine patients had noncatheter-related bacteremia. Five patients had catheter-related sepsis without proven bacteremia. There was no significant difference in median DTTP between patients with CR-BSI and noncatheter-related bacteremia (2.1 hrs and 3.3 hrs, respectively; p =.6). Moreover, catheter-related sepsis in patients without bacteremia could not be detected using DTTP. CONCLUSION: DTTP seems not to be useful for the diagnosis of CR-BSI in a medical-surgical intensive care unit.

Adult↗

PubMed1992

Peripheral intravenous catheter complications in critically ill children: a prospective study.

Six hundred fifty-four peripheral Teflon catheters in 303 pediatric intensive care unit patients were examined to determine complication rates and associated risk factors. Phlebitis, extravasation, and bacterial colonization occurred at rates of 13%, 28%, and 11%, respectively. Logistic regression of factors that increased phlebitis risk revealed infusion of hyperalimentation (odds ratio 2.9) or lorazepam (odds ratio 2.2) and catheter location (odds ratio 2.9) as the most important determinants of phlebitis risk. Age (less than or equal to 1 year, odds ratio 2.0), catheter time in situ (less than or equal to 72 hours, odds ratio 2.1), and infusion of antiepileptics (odds ratio 2.1) were the most important determinants of extravasation. Catheters were colonized most frequently with coagulase-negative Staphylococcus (51/54). Sepsis attributable to catheter colonization occurred in 1 patient. Duration of catheter placement (greater than or equal to 144 hours, odds ratio 5.8) was an important determinant of catheter colonization. Colonization risk increased from 11% in catheters that were in situ for 48 to 144 hours to 34% for catheters that were in for longer than 144 hours. Infusion of diazepam (odds ratio 11.0) or lipid emulsions (odds ratio 2.5) and age (less than or equal to 1 year, odds ratio 2.2) were also important determinants of colonization risk. Replacing catheters in critically ill children every 72 hours would not decrease phlebitis, bacterial colonization, or catheter-induced sepsis and could increase extravasation risk. Catheters can be safely maintained with adequate monitoring for up to 144 hours in critically ill children.

Catheterization, Peripheral↗

PubMed1993

Comparison of axillary artery or brachial artery pressure with aortic pressure after cardiopulmonary bypass using a long radial artery catheter.

Arterial pressure measured in a peripheral artery may significantly underestimate central arterial pressure after discontinuation of cardiopulmonary bypass (CPB). Arterial pressure measured with a 50 cm radial artery catheter advanced into the brachial or axillary artery was compared to ascending aortic pressure in 31 patients before and after discontinuation of CPB. The radial artery catheter extended proximally into the brachial artery in 8/31 patients, and into the axillary artery in 23/31 patients. The patient's age, pre-CPB cardiac ejection fraction, and surgical procedures were similar in both groups. The systolic arterial pressure measured in the ascending aorta was found to be significantly different from that in the axillary artery after CPB, whereas the mean and diastolic pressures were not. The average aorta-to-axillary artery systolic pressure gradient was -3.0 +/- 4.0 mmHg, with no patient having a gradient greater than 10 mmHg. The systolic and mean arterial pressures measured in the ascending aorta were found to be significantly different from that in the brachial artery after discontinuation of CPB, whereas the diastolic pressure was not. The average aorta-to-brachial artery systolic pressure gradient was 6.9 +/- 6.9 mmHg, with 3/8 patients having a gradient greater than 10 mmHg. Long radial artery catheters, placed using the Seldinger technique, provide an accurate estimate of central aortic pressure after CPB when they are advanced into the axillary artery. Sites more distal than the axillary artery may result in significant underestimation of the central aortic pressure in these patients.

Aged↗

PubMed2004

Comparison of EMLA and lidocaine iontophoresis for cannulation analgesia.

BACKGROUND AND OBJECTIVE: Eutectic mixture of local anaesthetic cream and lidocaine iontophoresis are effective in providing analgesia for peripheral venous cannulation with small gauge cannulae in adults and children. The objective of this study was to compare the analgesic efficacy of the two techniques directly in patients using larger cannulae. METHODS: In a double-blind, randomized, controlled study we compared the two techniques directly. Twenty-eight patients had the eutectic mixture of local anaesthetic cream applied to the dorsum of one hand for 60 min followed by sham iontophoresis (group EMLA); the other hand had a sham cream applied for 60 min followed by 10 min of 2 mA iontophoresis with lidocaine 4% and epinephrine 1 in 50,000 (group iontophoresis). Within 5 min of completion of iontophoresis an anaesthetist, unaware of treatment allocation, inserted 18-G venous cannulae into veins of both hands. The patient then scored the amount of pain on cannulation using a 10 point verbal rating scale. RESULTS: Eight patients were excluded from analysis due to failed cannulation (two group EMLA, two group iontophoresis), intolerable burning sensation from iontophoresis (one), protocol violation (one), and changes in surgical schedule (two). Pain scores were lower for the EMLA treated hand than for the iontophoresis side (median (range) 1 (0-7) vs. 3 (0-6); P = 0.023). Erythema and paraesthesia were common but short lived on the iontophoresis side. CONCLUSIONS: Although lidocaine iontophoresis is effective more quickly than the eutectic mixture of local anaesthetic cream, the superior quality of analgesia produced by the eutectic mixture in this study should be borne in mind if these treatments are used electively.

Adult↗

PubMed1998

Efficacy of peripherally inserted central venous catheters placed in noncentral veins.

BACKGROUND: Peripherally inserted central venous catheters (PICCs) are commonly used intravenous access devices in children. Although PICCs are intended to be placed in central veins, many fail to reach this location. These noncentral PICCs are used for administration of medications and isotonic solutions. OBJECTIVES: To examine the efficacy of noncentral PICCs for completion of therapy, the complications associated with their use, and the effectiveness of noncentral PICCs as compared with PICCs placed in a central vein. DESIGN: A prospective cohort study of children in whom PICCs were inserted, from January 1, 1994, to January 1, 1996. SETTING: A university-affiliated teaching institution. MAIN OUTCOME MEASUREMENT: Completion of intravenous therapy. RESULTS: A total of 587 PICCs were studied. Thirty-nine percent of PICCs were placed in noncentral veins. Centrally placed PICCs had significantly longer catheter duration compared with those placed noncentrally (16.6 vs 11.4 days, respectively). However, central and noncentral PICCs had similar therapy completion rates (73% and 69%, respectively). Catheter failure because of occlusion and accidental dislodgment were similar for central and noncentral PICCs. Likewise, complications caused by exit-site infection, phlebitis, and catheter-associated sepsis were also similar for catheters in the 2 locations. Catheter survival curves were similar for central and noncentral PICCs. CONCLUSIONS: Our study demonstrates that PICCs placed in noncentral veins provide reliable and safe intravenous access for administration of many medications and isotonic solutions for about 2 weeks' duration. The placement of PICCs in central veins may be restricted to those children who need central vascular access because of the type of intended therapy.

Catheterization, Central Venous↗

PubMed2000

Optimum intermittent pneumatic compression stimulus for lower-limb venous emptying.

OBJECTIVE: intermittent pneumatic compression (IPC) of the foot (IPC(foot)), calf (IPC(calf)) or both (IPC(foot+calf)) augments calf inflow, and improves the walking ability and peripheral haemodynamics of claudicants (IPC(foot), IPC(foot+calf)), largely due to venous outflow enhancement. This cohort study, using direct pressure measurements in healthy limbs, determines the optimal combination of frequency (2-4 impulses/minute), applied pressure (60-140 mmHg), mode (IPC(foot)-IPC(calf)-IPC(foot+calf)) and delay time of calf-to-foot impulse (0 s-0.5 s-1 s) that enables IPC to generate an almost complete and sustained decrease in venous pressure. RESULTS: (a) IPC(foot)at 120 and 80 mmHg generated lower venous pressure than that with 100 and 60 mmHg (p=0.036) respectively, for 2-4 impulses/minute; venous pressure differences between applied pressures of 140 and 120 mmHg or between 80 and 100 mmHg were insignificant. (b) Venous pressure with IPC(calf)at 80 mmHg was lower than that with 60 mmHg (p=0.036) (2-4 cycles/minute); differences in venous pressure between applied pressures of 140 and 100 mmHg or between 120 and 80 mmHg were insignificant. (c) At applied pressures 60-140 mmHg, IPC(foot+calf)with one-second delay generated lower venous pressure than that with half-second delay (p=0.036), the latter being more efficient than zero delay; increasing applied pressures produced lower venous pressure, but differences were small. Venous pressure decreased with increasing IPC frequency (from 2 to 3-4/minute), at applied pressures 60-140 mmHg. CONCLUSIONS: IPC(foot+calf)at applied 120-140 mmHg, a frequency of 3-4 impulses/minute and one-second delay, provided the optimum intermittent pneumatic stimulus.

Adult↗

PubMedDate not supplied

[Factors that influence the duration of peripheral venous catheters used to antibiotic therapy in Cystic Fibrosis patients: results of a study].

UNLABELLED: Antibiotic intravenous (IV) therapy is of paramount importance in the treatment of cystic fibrosis (CF) lung disease. During their life CF patients have to undergo frequent IV antibiotic treatments. Peripheral venous catheters (PVC) -or cannulas- are often used to reduce the number of venepunctures needed to complete a treatment cycle, as well as to provide patients the best possible level of autonomy. The clinical experience in managing IV therapy in CF patients at Meyer Hospital in Florence, suggested that the in situ duration of PVCs varies greatly. GOAL: To understand which factors influence the duration of PVCs used to administer IVantibiotic in people with CF. STUDY DESIGN: Cohort prospective study, integrated with retrospective data retrieval. MATERIALS, PATIENTS AND METHODS: We observed all the PVCs inserted during an 8-month period to CF patients followed at the CF Centre of Tuscany (Florence, Italy). RESULTS: We studied 87 PVCs inserted to 36 patients in 56 IV antibiotic treatment cycles. The mean duration of PVCs was 8.3 days. The mean duration of PVCs used for 3 daily antibiotic administrations was longer than that of PVCs used for 2 daily antibiotic administrations (10.3 days vs. 6.5 days, p=0.001). Moreover, PVCs with a larger gauge (G22) had longer mean duration than smaller (G24) PVCs (9.6 days vs. 7.2 days, p=0.03). No statistically significant association was found between PVCs' duration and, respectively, the place where the treatment was administered (in hospital or at home), the arm used (dominant or non-dominant), the PVC's brand, patient's clinical condition and the concurrent use of either steroidal antinflammatory drugs or NSAIDs per os.

Adolescent↗

PubMed2002

Complication rates among cancer patients with peripherally inserted central catheters.

PURPOSE: Peripherally inserted central catheters (PICCs) are frequently used to deliver outpatient courses of intravenous therapy. However, the rates and risks of complication for this device have not been well-studied. Our objective was to determine the incidence and risk factors of PICC-related complications with a 1-year prospective observational study. PATIENTS AND METHODS: All PICCs inserted in adult and pediatric patients at Memorial Sloan-Kettering Cancer Center (MSKCC) were followed prospectively. The device insertion team, inpatient nurses, and various home-care companies and outside institutions collected longitudinal data. RESULTS: Three hundred fifty-one PICCs were inserted during the study period and followed for a total of 10,562 catheter-days (median placement, 15 days; range, 1 to 487 days). Two hundred five PICCs (58%) were managed by home-care companies and outside institutions, and 146 PICCs (42%) were managed exclusively at MSKCC. For these 205 PICCs, 131 nurses from 74 home-care companies and institutions were contacted for follow-up clinical information. In all, 115 (32.8%) of 351 PICCs were removed as a result of a complication, for a rate of 10.9 per 1,000 catheter-days. Patients with hematologic malignancy or bone marrow transplant were more likely to develop a complication, whereas those with metastatic disease were less likely. CONCLUSION: Complications occur frequently among cancer patients with PICCs, and long-term follow-up is onerous. Despite a high complication rate, the ease of insertion and removal argues for continued PICC use in the cancer population.

Adolescent↗

PubMedDate not supplied

Arterial injuries from femoral artery cannulation with port access cardiac surgery.

Although minimally invasive (MI) cardiac surgery reduces blood loss, hospital stay, and recovery time, some MI approaches require femoral arterial cannulation, which introduces a heretofore unknown risk of femoral arterial injury. This study was performed to examine the risk of femoral arterial injury after Port Access MI cardiac surgery (PA-MICS) with femoral cannulation. Data were prospectively obtained on 739 consecutive patients who had PA-MICS with femoral cannulation between June 1996 and April 2000, identifying any patient with new (<30 days postoperative) arterial insufficiency from the cannulation site. Patient characteristics (gender, age, height, weight, body surface area, smoking, peripheral vascular disease, diabetes) and operative variables (cannula size, cross-clamp time) were examined with univariate and multivariate analysis to identify risk factors for arterial injury. Injuries were defined and classified by radiologic and intraoperative assessment, and follow-up was obtained by patient examination and from the medical records. Femoral arterial occlusion (FAC) occurred in 0.68% (5/739) of patients (4 women, 1 man; age range 26-74 years). The risk of femoral injury was higher in women: 1.31% vs 0.23% (p = 0.07). One patient had intraoperative limb ischemia from iliofemoral dissection and was treated by axillopopliteal bypass. Four patients presented postoperatively with claudication. Three of these had iliofemoral arterial occlusion or localized iliofemoral dissection and were treated with iliofemoral bypass, and 1 patient had localized femoral artery stenosis treated by angioplasty. With a mean follow-up of 17.8 months (range 13-26 months) limb salvage was achieved in all patients. Secondary or tertiary interventions were required in 40% (2/5), both in patients with iliofemoral occlusion, and 1 patient (20% of femoral injuries, 0.135% of overall series) has chronic graft occlusion and long-term claudication. The risk of arterial injury after femoral arterial cannulation and perfusion for Port Access surgery was low (0.68%). This risk is increased in women and is unpredictable. Initial vascular repair has a significant failure rate, and secondary interventions are often necessary. Although the femoral cannulation and perfusion technique is safe overall, the risk must be clearly recognized.

Adult↗

PubMed2006

The risk of bloodstream infection in adults with different intravascular devices: a systematic review of 200 published prospective studies.

OBJECTIVE: To better understand the absolute and relative risks of bloodstream Infection (BSI) associated with the various types of intravascular devices (IVDs), we analyzed 200 published studies of adults In which every device in the study population was prospectively evaluated for evidence of associated infection and microbiologically based criteria were used to define IVD-related BSI. METHODS: English-language reports of prospective studies of adults published between January 1, 1966, and July 1, 2005, were identified by MEDLINE search using the following general search strategy: bacteremla [Medical Subject Heading, MeSH] OR septicemia [MeSH] OR bloodstream Infection AND the specific type of intravascular device (e.g., central venous port). Mean rates of IVD-related BSI were calculated from pooled data for each type of device and expressed as BSIs per 100 IVDs (%) and per 1000 IVD days. RESULTS: Point incidence rates of IVD-related BSI were lowest with peripheral Intravenous catheters (0.1%, 0.5 per 1000 IVD-days) and midline catheters (0.4%, 0.2 per 1000 catheter-days). Far higher rates were seen with short-term noncuffed and nonmedicated central venous catheters (CVCs) (4.4%, 2.7 per 1000 catheter-days). Arterial catheters used for hemodynamic monitoring (0.8%, 1.7 per 1000 catheter-days) and peripherally inserted central catheters used in hospitalized patients (2.4%, 2.1 per 1000 catheter-days) posed risks approaching those seen with short-term conventional CVCs used in the Intensive care unit. Surgically implanted long-term central venous devices--cuffed and tunneled catheters (22.5%, 1.6 per 1000 IVD-days) and central venous ports (3.6%, 0.1 per 1000 IVD-days)--appear to have high rates of Infection when risk Is expressed as BSIs per 100 IVDs but actually pose much lower risk when rates are expressed per 1000 IVD-days. The use of cuffed and tunneled dual lumen CVCs rather than noncuffed, nontunneled catheters for temporary hemodlalysis and novel preventive technologies, such as CVCs with anti-infective surfaces, was associated with considerably lower rates of catheter-related BSI. CONCLUSIONS: Expressing risk of IVD-related BSI per 1000 IVD-days rather than BSIs per 100 IVDs allows for more meaningful estimates of risk. These data, based on prospective studies In which every IVD in the study cohort was analyzed for evidence of infection by microbiologically based criteria, show that all types of IVDs pose a risk of IVD-related BSI and can be used for benchmarking rates of infection caused by the various types of IVDs In use at the present time. Since almost all the national effort and progress to date to reduce the risk of IVD-related Infection have focused on short-term noncuffed CVCs used in Intensive care units, Infection control programs must now strive to consistently apply essential control measures and preventive technologies with all types of IVDs.

Catheterization↗

PubMed2004

Power injection of contrast media via peripherally inserted central catheters for CT.

PURPOSE: To evaluate patient safety, catheter rupture rates, and computed tomography (CT) image quality when using peripherally inserted central catheters (PICCs) in vivo for the power injection of CT contrast media at standard injection rates. MATERIALS AND METHODS: A prospective study to evaluate the safety and effectiveness of power injection of contrast media via indwelling PICCs was performed. Single-lumen and double-lumen polyurethane PICCs (5 F) were injected in vivo with contrast media for clinical CT examinations at injection rates ranging from 1 mL/sec to 4 mL/sec. Data collected included PICC rupture rate, patient complications, injection rate, peak injection pressure, PICC length, PICC age, and quality of contrast enhancement on the CT images. RESULTS: One hundred ten power injections of PICCs for CT examinations were performed. There were 12 injections of single-lumen PICCs and 98 injections of double-lumen PICCs. The most common injection rate was 2 mL/sec, accounting for 89 of the 110 injections (81%). Two PICCs ruptured during power injection, both as a result of operator error. One of the PICCs that ruptured was clamped at the time of injection and the other one was kinked at its venous entry site. One additional PICC showed evidence of dysfunction; it ballooned without actually rupturing. No significant patient complications occurred. Contrast enhancement of the CT images was subjectively rated as average or above average in 95% of cases. CONCLUSIONS: Contrast media can be power-injected via PICCs for routine CT examinations at a rate of 2 mL/sec, yielding satisfactory image quality without exposing patients to significant additional risk. Power injection rates greater than 2 mL/sec, as are typically used in CT angiography applications, were not fully evaluated by this study.

Adult↗

PubMed1989

Tobramycin administration and blood sampling through a dual-lumen peripheral intravenous catheter.

The objective of this study was to determine if a peripheral dual-lumen catheter could be used for accurate tobramycin blood concentration measurement when drug administration and blood sampling were undertaken through separate lumens of the catheter. Eleven adult volunteers received tobramycin 1.5 mg/kg iv infused over 30 minutes through the distal lumen of the dual-lumen catheter every eight hours for two doses. Multiple blood samples were obtained concurrently from the proximal lumen of the catheter and a single-lumen catheter in the contralateral arm after each dose. Blood samples were also obtained through the distal lumen before and 30 minutes after the end of the infusion. Accurate blood samples were obtainable through the dual-lumen catheter in only 5 of 11 subjects due to either infiltration or difficulties in catheter placement. In the subjects from whom accurate blood samples were obtained, approximately 20 minutes postinfusion was the amount of time required before measured tobramycin serum concentrations were similar between the arm in which the drug was infused (site of the dual-lumen catheter) and the contralateral arm. At standard times for obtainment of trough (just prior to the infusion) and peak (30 minutes after the end of a 30-minute infusion) tobramycin serum concentrations from the proximal lumen of the dual-lumen catheter were numerically similar to those obtained from the contralateral arm. This preliminary study indicates that the dual-lumen catheter provides accurate aminoglycoside concentrations when patent relative to blood withdrawal and if peak blood samples are obtained at least 30 minutes postinfusion through the recommended lumen. However, further study in a larger number of subjects is required before routine use of this device can be recommended.

Adult↗

PubMed1999

Effect of peripheral perfusion on accuracy of pulse oximetry in children.

STUDY OBJECTIVE: To examine the effect of perfusion on accuracy of two pulse oximeters in children and to determine thresholds of perfusion below which these pulse oximeters become inaccurate or cease to function. DESIGN: Prospective, observational clinical study. SETTING: Operating room of a large university hospital. PATIENTS: 19 children 10 years of age or less, who were scheduled for general anesthesia with placement of an intraarterial catheter. INTERVENTIONS: A radial artery catheter, laser Doppler probe, skin temperature sensor, and band probes of two oximeters, Ohmeda 3700 (Boulder, CO) and Nellcor N200 (Hayward, CA), were attached to the same hand. Baseline pulse oximeter and Doppler readings were obtained with simultaneous hemoximetry (AVL Model 912 CO-Oxylite, Roswell, GA), skin and esophageal temperatures, total hemoglobin, and transduced arterial pressure. Readings of all parameters (n = 94) were obtained during periods of low perfusion or by occluding the upper arm to 70% to 100% of systolic pressure. MEASUREMENTS AND MAIN RESULTS: Bias (SpO2-SaO2) of each oximeter is compared to each perfusion variable (age, weight, core and skin temperature, hemoglobin concentration, pulse pressure, and percent flow by laser Doppler) to determine effect on accuracy. Data were analyzed using backward multivariate linear regression, Pearson correlation coefficients, and independent paired t-test. p < 0.05 was considered significant. Less than 2% bias is seen with either oximeter (Nellcor 1.55 +/- 2.33, Ohmeda 0.78 +/- 2.25). Independent predictors of bias for each machine include weight (r = -0.376; p < 0.001) and pulse pressure (r = 0.250; p = 0.021) for the Nellcor, and weight (r = -0.390; p < 0.001), percent flow by Doppler (r = 0.220; p = 0.035), and core temperature (r = 0.307; p = 0.003) for the Ohmeda. However, using predetermined thresholds for each variable, only skin temperature below 30 degrees C is identified as a significant predictor of oximeter inaccuracy. CONCLUSIONS: At the parameters explored in this study, the selected seven perfusion variables (age, weight, core and skin temperature, hemoglobin concentration, pulse pressure, and percent flow by laser Doppler) have little effect on accuracy of pulse oximetry in children.

Age Factors↗

PubMed2002

Widespread coronary inflammation in unstable angina.

BACKGROUND: Inflammation within vulnerable coronary plaques may cause unstable angina by promoting rupture and erosion. In unstable angina, activated leukocytes may be found in peripheral and coronary-sinus blood, but it is unclear whether they are selectively activated in the vascular bed of the culprit stenosis. METHODS: We measured the content neutrophil myeloperoxidase content in the cardiac and femoral circulations in five groups of patients: two groups with unstable angina and stenosis in either the left anterior descending coronary artery (24 patients) or the right coronary artery (9 patients); 13 with chronic stable angina; 13 with variant angina and recurrent ischemia; and 6 controls. Blood samples were taken from the aorta, the femoral vein, and the great cardiac vein, which selectively drains blood from the left but not the right coronary artery. RESULTS: The neutrophil myeloperoxidase content of aortic blood was similar in both groups of patients with unstable angina (-3.9 and -5.5, with negative values representing depletion of the enzyme due to neutrophil activation) and significantly lower than in the other three groups (P<0.05). Independently of the site of the stenosis, the neutrophil myeloperoxidase content in blood from the great cardiac vein was significantly decreased in both groups of patients with unstable angina (-6.4 in those with a left coronary lesion and -6.6 in those with a right coronary lesion), but not in patients with stable angina and multiple stenoses, patients with variant angina and recurrent ischemia, or controls. There was also a significant transcoronary reduction in myeloperoxidase content in both groups with unstable angina. CONCLUSIONS: The widespread activation of neutrophils across the coronary vascular bed in patients with unstable angina, regardless of the location of the culprit stenosis, challenges the concept of a single vulnerable plaque in unstable coronary syndromes.

Aged↗

PubMed2000

Complications associated with the use of urokinase and recombinant tissue plasminogen activator for catheter-directed peripheral arterial and venous thrombolysis.

PURPOSE: Catheter-directed thrombolytic dissolution of peripheral arterial and venous thrombus is in widespread use, yet the frequency and nature of associated complications remain ill defined. In an effort to better characterize the complications associated with urokinase (UK) and recombinant tissue plasminogen activator (rt-PA), the clinical course of patients treated for lower extremity vascular occlusions at a single institution was reviewed. MATERIALS AND METHODS: Over a 9-year period, 653 consecutive patients were treated for lower extremity arterial (527 patients) or venous (126 patients) occlusions with catheter-directed UK (483 patients), rt-PA (144 patients), or both (26 patients). Decisions regarding the choice of thrombolytic agent were made by the clinician. In-hospital complications were subcategorized into hemorrhagic and nonhemorrhagic events and the rate of intracranial hemorrhage was specifically tabulated. RESULTS: There were no significant differences in the demographics or clinical presentation of patients treated with either UK or rt-PA. Bleeding complications occurred less often in the patients treated with UK (insertion site hematoma 21.9% vs. 43.8%, P<.0001, any bleeding necessitating transfusion 12.4% vs. 22.2%, P = .004, and intracranial hemorrhage 0.6% vs. 2.8%, P = .031). Cardiopulmonary complications necessitating transfer to the intensive care unit occurred more frequently in the patients treated with rt-PA (4.9% vs. 1.5%, P = .015). The risk of mortality was not statistically different between the UK and rt-PA treated patients (2.7% vs. 6.2%, P = .221). CONCLUSIONS: Thrombolysis appears safer with UK than with rt-PA, with a lower incidence of hemorrhagic complications. It is possible that this finding is related to differential dosing regimens or intrinsic pharmacologic differences between the agents. The observations of this retrospective analysis require confirmation with a prospective, randomized evaluation.

Arterial Occlusive Diseases↗

PubMedDate not supplied

Venous thrombosis associated with the placement of peripherally inserted central catheters.

PURPOSE: Peripherally inserted central catheters (PICCs) have become an essential component of the management of an increasing number of patients, including patients who may require hemodialysis. Reported symptomatic venous thrombosis rates associated with PICC lines are based on clinical signs and symptoms and range from 1% to 4%. The purpose of this study is to evaluate the true rate of thrombosis of upper extremity veins after the placement of PICCs and the potential impact on future access in hemodialysis patients. MATERIALS AND METHODS: A retrospective analysis was performed. Patients who had (i) normal findings during initial venography, (ii) PICC placement, and (iii) who underwent subsequent repeated venography were included. Age, sex, vein cannulated, catheter size, location, and incidence of thrombosis were analyzed. RESULTS: Three hundred fifty-four PICCs were placed in 119 patients. Of the 144 extremities, 137 had normal findings during initial venography. Of the 137 extremities, 32 developed thrombosis of the cannulated vein (or central veins) after initial PICC placement (23.3%). When all extremities with multiple PICC lines placed were considered, 52 developed thrombosis, for an overall thrombosis rate of 38%. The incidence of thrombosis by site was cephalic 57%, basilic 14%, and brachial 10%. No significant differences were noted in the rates of thrombosis by age, sex, or catheter size. CONCLUSIONS: There is a relatively high rate of venous thrombosis associated with PICCs, particularly cephalic thrombus. Because of the high rate of thrombosis associated with these catheters, an alternative mode of access should be considered in current or potential hemodialysis patients. All patients with a history of PICC line placement requiring dialysis access should undergo upper extremity venography prior to the placement of permanent access.

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