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PubMed1993

Inadvertent administration of positive end-distending pressure during nasal cannula flow.

In the clinical setting, nasal cannulas are frequently used to deliver supplemental oxygen to neonates and are not believed to affect the general respiratory status. In contrast, it was hypothesized that clinical changes associated with nasal cannula gas flow may be related in part to the generation of positive end-distending pressure. To test this hypothesis, alterations in esophageal pressure were quantified as an indication of end-distending pressure and thoracoabdominal motion was quantified as an indication of breathing patterns in 13 preterm infants at gas flow levels of 0.5, 1, and 2 L/min delivered by nasal cannula with an outer diameter of either 0.2 or 0.3 cm. Changes in esophageal pressure were assessed by esophageal balloon manometry. Ventilatory patterns were assessed from thoracoabdominal motion by using respiratory inductive plethysmography. Thoracoabdominal motion was quantitated as a phase angle (theta); larger values represent greater asynchrony. The 0.2-cm nasal cannula did not deliver pressure or alter thoracoabdominal motion at any flow. In contrast, the 0.3-cm nasal cannula delivered positive end-distending pressure as a function of increasing levels of gas flow (r = .92) and reduced thoracoabdominal motion asynchrony. The mean pressure generated at 2 L/min was 9.8 cm H2O. These data demonstrate that nasal cannula gas flow can deliver positive end-distending pressure to infants and significantly alter their breathing strategy. This finding raises important concerns about the indiscriminate therapeutic use, size selection, and safety of nasal cannulas for the routine delivery of oxygen in preterm infants.

Equipment Design↗
PubMedDate not supplied

High flow/low resistance cannulas for percutaneous arteriovenous carbon dioxide removal.

Percutaneous cannulas with low resistance are necessary for arteriovenous carbon dioxide removal (AVCO2R) to allow highest flow at lowest pressure to maximize CO2 removal. Commercially available arterial (A) and venous (V) percutaneous cannulas (8-18 Fr) were tested for pressure/flow characteristics under conditions that simulated percutaneous AVCO2R at clinically pertinent flow rates between 200-1000 ml/min to obtain the M number previously described by Delius, et al. The Bio-Medicus (Bio-Medicus, Grand Rapids, MI) 17F A, Research Medical, Inc (RMI) (Model FEM II, Research Medical, Inc., Midvale, UT) 16F A, and RMI 18F V cannulas exhibited the lowest M numbers that correlated with low resistance to flow. The four most clinically favorable arterial cannulas (8, 10, 12, and 14 Fr), coupled with a venous cannula four French sizes larger, were used in an AVCO2R circuit in adult sheep (n = 3) at varying mean arterial pressures (MAP) between 65-105 mmHg. The 8, 10, 12, and 14 Fr arterial cannulas allowed an arteriovenous flow of 208 +/- 72, 530 +/- 37, 848 +/- 66, and 944 +/- 96 ml/min, respectively, at a MAP of 65 mmHg. An increase in MAP to 105 mmHg was associated with approximately a 41, 30, 32, and 27% increment in blood flow, respectively. In summary, an arterial percutaneous cannula of 10 Fr or larger will allow AVCO2R blood flow greater than 500 ml/min, as previously shown by Brunston et al. to achieve total CO2 removal without incurring hypercapnia.

Adult↗
PubMed1988

Life span of intravenous cannulas in a neonatal intensive care unit.

Peripheral intravenous cannula use in a neonatal intensive care unit was surveyed prospectively to ascertain the rate of complications and the factors influencing the life span of an intravenous cannula. During a three-month period in which 199 intravenous cannulas were inserted in 69 patients, only two significant infiltrations (1%) were observed in more than 5000 hours of intravenous therapy. None of the factors studied, including weight, age, type and rate of fluid administration, and type of medication (except pancuronium bromide), had any discernible effect on the functional life span of intravenous cannulas. Pancuronium was associated with a significant prolongation of cannula life span--from 30 to 50 hours. We conclude that in this setting, the rate of clinically significant complications from intravenous cannula therapy is low.

Catheterization, Peripheral↗
PubMed1976

A comparison of flexible and nonflexible plastic cannulae for performing first trimester abortion.

The safety and effectiveness of flexible and nonflexible plastic cannulae used in vacuum aspiration abortion for patients at 6 to 12 weeks' gestation were evaluated in a study of 1100 physically healthy women in Ljublijana, Yugoslavia. To minimize study biases, each type of cannulae was randomly assigned to 550 patients. To minimize evaluator bias, a second physician who was kept unaware of which cannula was used for particular patient was responsible for evaluating patients after the procedures. Both groups of patients were similar with respect to age, parity, marital status, formal education and gestational age. Higher rates of retained tissue and cannula obstruction were obtained with the flexible cannula. The two types of cannulae were not significantly different with respect to other criteria of evaluation.

Abortion, Induced↗
PubMed1979

Observations of HRP labeling following injection through a chronically implanted cannula--a method to avoid diffusion of HRP into injured fibers.

One of the limitations of the horseradish peroxidase (HRP) tracer method is the diffusion of HRP into injured axons resulting in unintended labeling of neurons not terminating in the injection area. To overcome this limitation, an experiment was designed to inject the HRP through an implanted cannula after degeneration and healing had taken place. It was shown that implantation of a cannula into the internal capsule significantly decreased the number of labeled axons in the injection site, thus limiting the unintended labeling of neurons from that injection. When injections followed implantation of the cannula by 24 h or more, fibers damaged by the cannula had healed or degenerated sufficiently that intraaxonal diffusion of HRP into those injured fibers did not occur. A significant difference between control (without the cannula) and experimental (with the cannula) injections was observed. Extensive axonal and neuronal labeling following the control injections was seen at the injection site and caudate nucleus, and in the thalamus and parietal cortex, respectively. Experimental injections resulted in sparse axonal and neuronal labeling evident mostly with the larger injections of HRP.

Amygdala↗
PubMed1987

A small-gauge cannula device for continuous infusion of exogenous agents into the brain.

A method is described for the construction of an intraventricular or intraparenchymal cannula device, which when connected to an Alzet osmotic pump, can be used for the continuous infusion of experimental solutions into the brain. A 33-gauge, stainless-steel cannula is encased within a dental acrylic stabilization platform prior to stereotaxic implantation, and after implantation, the platform is glued to the animal's skull using cyanoacrylate adhesive. This procedure provides for the long-term stability (at least 4 weeks) of the small-gauge cannula without the need for additional stabilization skull screws, thus minimizing damage to surrounding tissues by the cannula and postsurgical trauma to the animal. Using the stock model 2002 Alzet pump to infuse artificial cerebral spinal fluid at a flow rate equal to 0.5 microliter/h, an inflammatory tissue reaction around the cannula tip was consistently found after 2 weeks of continuous intraparenchymal infusion. However, the inflammatory reaction could be significantly reduced or eliminated by decreasing the flow rate to approximately 0.25 microliter/h, using a modified Alzet pump. Alternatively, the stock 0.5 microliter/h pump could be used without causing parenchymal damage if the cannula tip was implanted into the lateral ventricle.

Animals↗
PubMed1996

Needle thoracocentesis in tension pneumothorax: insufficient cannula length and potential failure.

Advanced Trauma Life Support guidelines recommend the use of a cannula 3 to 6 cm long to perform needle thoracocentesis for life-threatening tension pneumothorax. The chest wall thickness in the 2nd intercostal space, mid-clavicular line, was determined by ultrasound in 54 patients aged 18 to 55 years, and ranged from 1.3 to 5.2 cm (mean 3.2 cm). In thirty-one patients (57 per cent) the chest-wall thickness (CWT) was greater than 3 cm, the minimum recommended cannula length, although in only two (4 per cent) was it greater than 4.5 cm, the length of cannula commonly used in the UK. As a 3 cm cannula would fail to reach the pleural cavity in over half of patients, we suggest that the recommended shortest length be increased to 4.5 cm. Unsuccessful needle thoracocentesis using a 4.5 cm cannula should be followed immediately by insertion of a longer cannula or a definitive chest drain.

Adolescent↗
PubMed1985

A quantitative evaluation of stress associated with indwelling superior vena cava cannulae in rats.

"Nonrestraining" superior vena cava (SVC) cannulae are commonly used in rat metabolic studies. The objective of this study was to evaluate the level of stress and metabolic alterations associated with surgical placement and subsequent maintenance and use of an indwelling intravenous cannula as measured by resting energy expenditure (REE), respiratory quotient (RQ), urinary nitrogen excretion, and substrate utilization pattern. Nine rats underwent SVC cannulation and six rats underwent sham operation. Postoperatively, animals were starved for 48 hr and then refed either parenterally or orally for 48 hr. Sham-operated animals adapted appropriately to starvation within 24 hr by decreasing REE 14% and increasing utilization of fat (RQ:0.89----0.78). Hypometabolic adaptation to starvation was delayed in cannulated animals until the second postoperative day, but appropriate alterations in energy substrate utilization were not affected by the presence of cannulae. Cannulae did not affect the metabolic response to oral refeeding with similar increases in REE and similar patterns of substrate utilization in sham-operated and cannulated animals. Animals refed parenterally demonstrated higher REE and apparent fat deposition (RQ greater than 1) consistent with continuous hypercaloric glucose administration. Urinary nitrogen excretion was not affected by the presence of cannulae. Cannula-associated metabolic alterations are minimal and transient and do not preclude detection and quantification of alterations associated with composition or utilization of exogenous substrates.

Animals↗
PubMed1983

Glass-plastic push-pull cannula system for regional perfusion of sites in the brain.

A new non-metallic push-pull cannula device is described for the localized perfusion of brain sites in the rat or other animal. Comprised entirely of glass and plastic materials, the cannula is intended for usage in an experiment in which the presence in tissue of metal tubing for delivery of perfusate is methodologically inappropriate. The main features of the cannula include its light weight, a Delrin pedestal base, a micro-glass guide tube, a polyethylene stylet, plastic spacers for adjustment of depth of perfusion, a protective cap for the chronic maintenance of the preparation, low cost and re-usability. The push-pull cannula is of concentric design and is fashioned from glass capillary and polyethylene tubing which are bonded at their common junctions by an epoxy cement. During a push-pull perfusion a special perfusion cap is used not only to hold the cannula firmly in place but also to protect the glass components from external damage. To further coincide with the metal-free requirements of the preparation, bone screws of nylon are used during the surgical implantation of the pedestal base. A prototype experiment illustrating its use in an unrestrained animal also is presented. The special applications for this cannula system are discussed which include its usage in experiments in either the anesthetized or unanesthetized rat exposed to microwave radiation where the presence of metal in the field would result in unwanted 'hot spots' in the cerebral tissue.

Animals↗
PubMed1983

A comparative study of intravenous cannulae--'Venflon' with valved sideport and 'Intraflux' with membranous sideport.

The rate of contamination of the inner surface of 'Venflon' type cannulae with valved injection sideports was compared with that of 'Intraflux' type cannulae with membranous injection sideports. Of 46 'Venflon' cannulae and 34 'Intraflux' cannulae, 17.4 per cent and 20.6 per cent, respectively, were contaminated and no correlation of contamination of lumen was found with frequency of use of the sideports in the different cannulae, or with duration of use of the cannulae.

Bacteria↗
PubMed1983

Bacterial contamination of 'Venflon' intravenous cannulae with valved injection sideport.

Eighty-eight intravenous cannulae with valved injection sideports were examined bacteriologically after approximately three days (64-80 h) normal clinical use. Three methods of culture of the cannulae were used, which distinguished contamination of the outer and inner surfaces as well as detecting bacteria remaining on the inner cannula surface following a washing procedure of the lumen. Of the cannulae sampled, 40.9 per cent were found to be contaminated on their inner surfaces and no correlation was obtained between use of the sideport and contamination of the cannulae at this site. It was concluded that contamination of a cannula lumen did not necessarily result in bacteraemia.

Adult↗
PubMed1989

Effects of heparin and chlorbutol on bacterial colonisation of intravascular cannulae in an in vitro model.

An in vitro model was used to study the effects of heparinised saline, with or without the preservative chlorbutol, on the colonisation of intravascular cannulae. Chlorbutol significantly reduced cannula colonisation by Staphylococcus epidermidis. Flushing colonised cannulae with heparinised saline plus chlorbutol significantly reduced the number of organisms adhering to the inner surface of cannulae, when compared with the use of heparinised saline without preservative. Chlorbutol-preserved heparinised saline may not only maintain cannula patency by the prevention of thrombus formation, but may also reduce the incidence of bacterial colonisation of cannulae in vivo.

Bacterial Infections↗
PubMed1991

Reduction in the colonization of central venous cannulae by mupirocin.

In an in-vitro simulation of an intravascular cannula enclosed in a fibrin sheath, 0.03 mg1(-1) of mupirocin prevented significant colonization [greater than 15 colony forming units (cfu)] by two clinical isolates of Staphylococcus epidermidis and one each of S. saprophyticus, S. hominis and S. haemolyticus. This suggests that in vivo, where protein binding of mupirocin is 95-97%, 1 mg 1(-1) of mupirocin at the cannula surface would be required to prevent colonization. These results support the findings of our previously published prospective controlled trial, in which mupirocin applied to the insertion sites of 172 internal jugular cannulae reduced the rate of colonization of cannula tips to 5%, compared with 25% for the 186 controls (P less than 0.001). Of the 46 colonized cannula tips from 110 control patients, the same species was isolated from the skin of the insertion site in 67% and from the lumen flush in only 15%. Analysed by patient, mupirocin reduced the proportion of patients with colonized tips from 17% to 3% after 24 h of infection, and from 35 to 10% after 48 h (P = 0.002). The use of agar containing charcoal, as a mupirocin neutralizer, and the incubation of tip-culture plates flooded with the Oxford staphylococcus, gave no evidence of carry over of mupirocin onto cannulae removed from mupirocin-treated patients.

Administration, Topical↗
PubMed2006

A novel technique using echocardiography to evaluate venous cannula performance perioperatively in CPB cardiac surgery.

OBJECTIVE: Transthoracic echocardiography (TTE) has been used clinically to disobstruct venous drainage cannula and to optimise placement of venous cannulae in the vena cava but it has never been used to evaluate performance capabilities. Also, little progress has been made in venous cannula design in order to optimise venous return to the heart lung machine. We designed a self-expandable Smartcanula (SC) and analysed its performance capability using echocardiography. METHODS: An epicardial echocardiography probe was placed over the SC or control cannula (CTRL) and a Doppler image was obtained. Mean (V(m)) and maximum (V(max)) velocities, flow and diameter were obtained. Also, pressure drop (DeltaP(CPB)) was obtained between the central venous pressure and inlet to venous reservoir. LDH and Free Hb were also compared in 30 patients. Comparison was made between the two groups using the student's t-test with statistical significance established when p<0.05. RESULTS: Age for the SC and CC groups were 61.6+/-17.6 years and 64.6+/-13.1 years, respectively. Weight was 70.3+/-11.6 kg and 72.8+/-14.4 kg, respectively. BSA was 1.80+/-0.2 m(2) and 1.82+/-0.2 m(2), respectively. CPB times were 114+/-53 min and 108+/-44 min, respectively. Cross-clamp time was 59+/-15 min and 76+/-29 min, respectively (p=NS). Free-Hb was 568+/-142 U/l versus 549+/-271 U/l post-CPB for the SC and CC, respectively (p=NS). LDH was 335+/-73 mg/l versus 354+/-116 mg/l for the SC and CC, respectively (p=NS). V(m) was 89+/-10 cm/s (SC) versus 63+/-3 cm/s (CC), V(max) was 139+/-23 cm/s (SC) versus 93+/-11 cm/s (CC) (both p<0.01). DeltaP(CPB) was 30+/-10 mmHg (SC) versus 43+/-13 mmHg (CC) (p<0.05). A Bland-Altman test showed good agreement between the two devices used concerning flow rate calculations between CPB and TTE (bias 300 ml+/-700 ml standard deviation). CONCLUSIONS: This novel Smartcanula design, due to its self-expanding principle, provides superior flow characteristics compared to classic two stage venous cannula used for adult CPB surgery. No detrimental effects were observed concerning blood damage. Echocardiography was effective in analysing venous cannula performance and velocity patterns.

Adult↗
PubMed2006

Developing a Research base for Intravenous Peripheral cannula re-sites (DRIP trial). A randomised controlled trial of hospital in-patients.

BACKGROUND: There is currently no high grade evidence on which to base decisions about the frequency of intravenous cannula re-sites. OBJECTIVE: To assess the safety of changing peripheral venous cannulas when clinically indicated. DESIGN: Randomised controlled trial. SETTING: A tertiary referral hospital in Brisbane, Australia. PARTICIPANTS: Two hundred and six hospitalised patients from surgical, medical and orthopaedic wards. INTERVENTIONS: Peripheral intravenous cannulas were re-sited only when complications occurred (intervention group) or every 3 days (control group). MAIN OUTCOME MEASURES: The primary endpoint was any unplanned cannula removal, the secondary outcome was cost. RESULTS: Forty six patients had unplanned removals in the intervention group compared with 41 in the control group [relative risk 1.12, 95% confidence interval 0.81-1.55 (p=0.286)], a non-significant difference. Total duration of peripheral cannulation was similar in both groups (mean 123.3h in the intervention group and 125.9h in the control group: P=0.82) but significantly more re-sites occurred in the control group (167 in intervention group, 202 in the control group: p=0.022). Cost of cannula replacements in the intervention group was AUD$3,183.62 and in the control group AUD$3,837.56 (p=0.006). CONCLUSION: Re-siting peripheral venous cannulas when clinically indicated compared with changing them routinely every 3 days does not lead to more complications and reduces costs.

Catheterization, Peripheral↗
PubMed1977

A newly designed arterial monitoring/perfusion cannula for cardiac operations.

A newly designed arterial monitoring and perfusion cannula for cardiopulmonary bypass eliminates the need for cannulation of a peripheral artery for pressure monitoring. The double-lumen cannula is designed as follows: the large central lumen (12 to 26f) acts as the arterial inflow conduit from the pump oxygenator, while a second, smaller lumen (18 gauge)constructed in the wall of the first cannula acts as the pressure-monitoring port and the source for blood sampling and drug infusion. This monitoring/perfusion cannula has been used succesfully in more than 250 clinical patients in a variety of settings--total cardiopulmonary bypass, left heart bypass, and when multiple arterial inflow lines were necessary (as in aortic arch replacement). Use of this cannula is advantageous in the infant and pediatric patient or in the emergency setting, when insertion of a peripheral arterial line can be difficult. Used in conjunction with a Doppler system, the cannula provides accurate, dependable blood pressure monitoring.

Blood Pressure↗
PubMed2002

Randomized trial of a Slip-Coat cannula for early abortion.

The objective of the study was to determine the effectiveness of a 6-mm coated cannula with Slip-Coat lubrication to avoid mechanical dilatation for abortion up to 712 weeks gestation. A blinded, randomized control trial of 50 healthy women, > or =18 years old, up to 54 days pregnant by ultrasound, requesting a surgical abortion was conducted. A successful outcome was defined as a completed abortion without the need for mechanical cervical dilatation. Of the 50 women, 29 received a Slip-Coat cannula, and 21 received a standard cannula. There were no overall differences in efficacy of the Slip-Coat cannula (17/29 or 59%) compared with the control group (12/21 or 57%, p = 0.91), or the acceptability of the procedure (93% versus 91%, respectively, p = 0.74), the level of pain (48 vs. 35, respectively, p = 0.052), acceptability of pain (66% vs. 67%, respectively, p = 0.93), or acceptability of bleeding (90% vs. 86%, respectively, p = 0.67). It was concluded that Slip-Coat cannulae were more effective than standard control cannulae for women who had no prior live births (6/10 or 60% vs. 0/7 or 0%, respectively, p = 0.01). This finding warrants further study.

Abortion, Induced↗
PubMed2003

Left upper quadrant cannula insertion.

OBJECTIVE: To determine the safety and efficacy of primary left upper quadrant laparoscopic cannula insertion. DESIGN: Retrospective review. SETTING: Tertiary care medical center. PATIENT(S): Women undergoing laparoscopic surgery for gynecologic indications. INTERVENTION(S): Left upper quadrant cannula insertion. MAIN OUTCOME MEASURE(S): Intraoperative complications. RESULT(S): Primary left upper quadrant cannula insertion was performed 58 times. There were no intraoperative complications. In one woman there was more pain at the LUQ site than at her other incisions. In 12 women (21%) adhesiolysis was performed before insertion of the umbilical cannula. CONCLUSION(S): Primary left upper quadrant cannula insertion is a safe and effective alternative to primary umbilical cannula insertion.

Catheterization↗