Effect of venipuncture sites on hematologic and clinical biochemical values in desert tortoises (Gopherus agassizii)

Paired blood samples were collected from the postoccipital venous plexus and jugular vein of desert tortoises (Gopherus agassizii) for hematologic and plasma biochemical analyses. Comparison of hematologic values revealed significantly (P < or = 0.05) lower PCV, RBC count, WBC count, and hemoglobin values for samples obtained from the occipital site. When comparisons were made between plasma biochemical values for the 2 sites, significant (P < or = 0.05) differences were measured for: glucose, potassium, chloride, uric acid, calcium, phosphorous, total protein, albumin, globulin, alkaline phosphatase, aspartate transaminase, alanine transaminase, and total cholesterol. Significant differences between hematologic and plasma biochemical values from the occipital region samples vs jugular vein samples were attributed to hemodilution of the occipital region samples with extravascular fluid or lymph or both.

The effect of prolonged tourniquet application on serum bicarbonate

BACKGROUND

Many clinicians believe that prolonged tourniquet application lowers the serum bicarbonate concentration in samples drawn from that limb, but this effect has never been examined prospectively.

OBJECTIVE

To test the effect of prolonged tourniquet application before phlebotomy on serum bicarbonate concentration in healthy adults.

METHODS

We drew blood samples from 27 healthy adult volunteers without a tourniquet and again 1, 3, and 5 minutes after applying a blood pressure cuff and inflating it to the mean arterial pressure.

RESULTS

The mean bicarbonate concentration was 27.3 +/- 2.26 mmol/L (standard deviation) at baseline, 27.7 +/- 2.39 mmol/L at 1 minute, 27.7 +/- 2.05 mmol/L at 3 minutes, and 27.7 +/- 1.96 mmol/L at 5 minutes. The mean change in bicarbonate concentration from baseline was -0.04 +/- 1.02 mmol/L at 1 minute, 0.44 +/- 1.05 mmol/L at 3 minutes, and 0.44 +/- 1.31 mmol/L at 5 minutes. The mean lactate concentration was 1.1 +/- 0.28 mmol/L at baseline, 1.3 +/- 0.65 mmol/L at 1 minute, 1.2 +/- 0.52 mmol/L at 3 minutes, and 1.2 +/- 0.36 mmol/L at 5 minutes. The mean change in lactate concentration from baseline was 0.15 +/- 0.67 mmol/L at 1 minute, 0.11 +/- 0.11 mmol/L at 3 minutes, and 0.12 +/- 0.37 mmol/L at 5 minutes.

CONCLUSIONS

Prolonged tourniquet application before phlebotomy does not lower the serum bicarbonate concentration in healthy adults.

Cannulation of the axillary artery in critically ill newborn infants

The axillary artery has been successfully cannulated in critically ill adult and paediatric patients. There is little information about experience with this technique in neonates. We report the use of axillary cannulation in 62 mechanically ventilated neonates with birth weight from 750 to 3800 g (mean 1950 g). The axillary artery was catheterized with 24 or 22 gauge teflon catheters by means of the catheter-over-a-needle technique. Arterial access was used for blood pressure monitoring, blood sampling and in seven cases for blood removal during exchange transfusions. Cannulae were removed when the fraction of inspired oxygen (FIO2) was less than 0.3. During cannulation capillary refill, radial artery pulse and neurological status of the arm were checked daily. The mean period of cannulation was 4.1 days (1-10 days). During cannulation and after catheter removal there were no complications related to the chosen vessel e.g. no change in the skin colour, skin warmth, capillary refill and the quality of the radial pulse. No changes in the motor activity of the limb on the cannulated side were observed.

CONCLUSION

Axillary artery cannulation is a useful alternative for establishing an arterial access in ventilated neonates. Further studies are needed to evaluate the long-term consequences of this technique.

A safer technique of internal jugular venipuncture: experience with 320 cases

Placement of central venous catheters for monitoring or long-term access has become an indispensable surgical procedure. Various routes to establish central venous access have previously been described. The internal jugular vein can be cannulated percutaneously from several access points, using the clavicle and the sternocleidomastoid muscle as reference landmarks. An alternate method of internal jugular venipuncture using a previously undescribed point of entry is described. Experience with this modified technique in 320 cases where it was used for various purposes is reviewed. The incidence of complication was less than 1% and the improved safety of the procedure is attributed to the vertical direct method of venipuncture through the new access point.

Percutaneous central venous access for resuscitation in trauma

OBJECTIVE

To determine the safety of percutaneous central venous access when used for trauma resuscitation and whether the initial hemodynamic status of the patient or the site of placement affects the ease or success of line placement.

METHOD

Consecutive major-trauma patients were managed using a resuscitation protocol guiding intravenous line use. Percutaneous peripheral venous access was initially attempted in all patients. If this approach was unsuccessful or proved to be inadequate for volume resuscitation, venous access was attempted using central venous catheter-introducer sets. The site of the central venous access was determined by protocol. For thoracic injury, access was via the ipsilateral subclavian vein (SCV), the ipsilateral internal jugular vein (IJV), or the femoral vein. For suspected mediastinal injury, access was via the contralateral SCV or IJV, or the femoral vein. For abdominal or flank injury, access was via the SCV or IJV only. Multiple central venous access sites were used at the discretion of the trauma team.

RESULTS

Central venous access was successful at 144 of 147 sites (99%) used in 122 patients during the study period. There was only one major complication (rate = 0.7%; 95% CI 0.0-3.8%). Mean catheter placement time was 1.9 minutes, and cannulation occurred with a mean of 1.8 needle passes. Most patients (81/122) were hypotensive (blood pressure < or = 90 torr) at the time of line placement, including 44 who were in cardiac arrest and four awake patients who had no obtainable blood pressure. Neither the access site nor the presence of hypotension was associated with the mean time to obtain central venous access, the mean number of attempts, or the complication rate.

CONCLUSION

Percutaneous central venous access is relatively safe and reliable for gaining intravenous access when resuscitating trauma patients, when used in a center where physicians are experienced in the technique. Consideration should be given to expanding the use of central venous access in trauma resuscitation.

Evaluation of the safety and efficacy of topical nitroglycerin ointment to facilitate venous cannulation

The purpose of this study was to determine the safety and efficacy of 2% nitroglycerin ointment to facilitate venous cannulation. In a double-blind experimental design, 80 adult subjects were randomly assigned to receive a 2% nitroglycerin ointment or a placebo ointment prior to cannulation. Variables measured before and after ointment application included heart rate, electrocardiogram, vein size, and presence of headache. No statistically significant differences were found in vein size or adverse effects following nitroglycerin ointment application.

Bloodletting

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Venipuncture tips for radiologic technologists

Radiologic technologists may be called upon to perform venipuncture to start intravenous lines to administer contrast media. This article provides advice to facilitate successful venipuncture techniques. It should not be considered a substitute for appropriate training.

A new approach to percutaneous subclavian venipuncture to avoid lead fracture or central venous catheter occlusion

Pacemaker and defibrillator leads and central venous catheters placed by commonly recommended techniques have been found to pass through the subclavius muscle, the costocoracoid ligament, or the costoclavicular ligament before entering veins medial to the first rib. Entrapment by these soft tissues subjects leads and catheters to stresses imposed by movements of the ipsilateral upper extremity. Accordingly, a new approach has been developed that introduces the lead or catheter into the subclavian vein near the lateral border of the first rib. This placement avoids soft tissue entrapment and may extend the longevity of leads and catheters.

Wristband identification error reporting in 712 hospitals. A College of American Pathologists' Q-Probes study of quality issues in transfusion practice

The correct wristband identification of patients is essential to prevent acute, hemolytic transfusion reactions from incompatible transfusion. We compared wristband identification errors for 712 hospitals. Phlebotomists checked patient wristbands on 2,463,727 occasions, finding 67,289 errors; in 33,308 instances, patient wristbands were missing entirely. The median total error rate was 2.2%; 10% of participants had error rates of 10.9% or greater. Absent wristbands represented 49.5% of errors; multiple wristbands with different information, 8.3%; wristbands with incomplete data, 7.5%; erroneous data, 8.6%; illegible data, 5.7%; and patients wearing wristbands with another patient's identifying information, 0.5%. The monitoring for errors by phlebotomy staff was the most important policy associated with lower error rates. Initial placement of wristbands by nursing staff was the only policy associated with increased error rates. We conclude that wristband identification error rates depend on differences in hospital policy and procedure and should be responsive to quality improvement efforts.

Rate of iron reaccumulation following iron depletion in hereditary hemochromatosis. Implications for venesection therapy

Although venesection therapy is well established for the initial depletion of iron stores in hereditary hemochromatosis, the frequency of subsequent therapy has not been clearly defined. In this study, 21 homozygotes (16 male, five female; mean age of 58, with a range of 26 to 77 years) who had completed initial venesection therapy were followed without further venesections for a mean of 4.0 years (range of 1 to 10.4 years) with iron reaccumulation assessed by annual serum ferritin concentration. Over the follow-up period, the mean rise in serum ferritin was 99 (micrograms/l)/year (range of 1.2 to 241 micrograms/l). The mean interval for the ferritin to become elevated above the normal range in 10 patients was 3.8 years. Eleven of 21 patients required no further venesection therapy over the follow-up interval. There was no significant correlation between the annual rate of ferritin increase and the age or amount of iron removed by prior venesections. These data demonstrate that monitoring body iron stores annually and the selective use of venesections if iron stores reaccumulate is a safe alternative to lifelong venesections every 2-4 months. Many homozygotes will not require reinitiation of venesection therapy for > 4 years. Annual monitoring of body iron stores with reinstitution of weekly venesection when the serum ferritin exceeds the upper limit of normal was a safe alternative to long-term maintenance venesection.