Disposable Circuit Research Articles

Single-Center Experience of Control of Ventilator-Circuit-Transmitted Burkholderia cepacia Outbreak in an Intensive Care Unit.

Burkholderia cepacia is an emerging nosocomial pathogen frequently associated with outbreaks, but the exact transmission route of this pathogen can at times be elusive in spite of extensive environmental investigative cultures. Active surveillance for sputum cultures was performed for all patients from September 2008 to September 2009 in an intensive care unit (ICU) with B. cepacia outbreak. With evidence of persistent positive conversion of sputum cultures (colonization) and infections among patients, discontinuing re-usable ventilator circuits was introduced. A total of 689 patients were admitted to this unit for a mean duration of 8.7 ± 7.5 days. There were 489 patients (71.0%) with a stay for one to ten days; 161 (23.4%) patients for 11 to 20 days; and 39 (5.7%) with over 20 days. In the first group, 13.5% of patients had cultures converting from negative to positive, in contrast to 66.7% in the last group (p < 0.01). With intervention of using disposable ventilator circuits since June 2009, the incidence of isolated B. cepacia decreased gradually. The estimated 30-day isolation-free probabilities of the groups before, during, one month (August 2009) after, and two months (September 2009) after this intervention were 38.5%, 47.3%, 66.5%, and 96.0%, respectively (p < 0.01). Furthermore, the effect of discontinuing reusable ventilator circuit persisted in the following 6 years; both total isolates of B. cepacia and the infection caused by it were much lower compared to the outbreak period. In summary, this six-year outbreak in a medical ICU persisted until reusable ventilator circuits were discontinued in 2009. The effect of disposable circuits on the decreased incidence of B. cepacia infection maintained in the following years.

Comparison Study between Using Disposable and Non-Disposable Ventilator Circuits on Ventilator-Associated Pneumonia and Health Care Costs at a Respiratory Care Unit, Siriraj Hospital

Objective: This research aimed to compare the incidence of ventilator-associated pneumonia (VAP) and ventilator circuit costs among patients using disposable ventilator circuits and patients using non-disposable ventilator circuits.&#x0D; Materials and Methods: Observational research was performed consisting of the following: A retrospective chart review of a group of patients who used non-disposable circuits (n=193) and a prospective cohort study of a group of patients using disposable circuits (n=166). The sample was purposively selected based on the following inclusion criteria: patients aged 18 years old and over who were admitted to the Respiratory Care Unit, Siriraj Hospital and ventilated &gt;48 h.&#x0D; Results: VAP incidence in the group non-disposable circuits was 10.41/1,000 ventilator days (n=27, 13.8%) and 10.82 /1,000 ventilator days (n=24, 14.4%) in the group disposable circuits (p=0.871). According to the data analysis using the U-control chart, no statistically significant differences were found. The unit cost of the non-disposable circuit was lower than that of the disposable circuit (THB 295.94), while the work unit personnel satisfaction toward working with disposable circuits was at a good level (Mean=3.83) and medium level (Mean=3.12) in non-disposable circuits (p=0.002).&#x0D; Conclusion: The type of ventilator circuits had no effects on VAP rate. The unit cost of non-disposable circuits was lower than that of disposable circuits, while the work unit personnel had a higher satisfaction working with disposable circuits than non-disposable circuits.

Foreign body obstructing fresh gas flow through disposable breathing circuit.

Foreign body obstructing fresh gas flow through disposable breathing circuit.

Comparison of ventilator-associated pneumonia in children using disposable and nondisposable ventilator circuits

Aims: The aim of the study was to compare the incidence of ventilator-associated pneumonia (VAP), mortality, and ventilator circuit-related cost associated with patients using disposable ventilator circuit to those associated with patients using nondisposable ventilator circuit. Setting and Design: A prospective randomized controlled study in a 10-bed Pediatric Intensive Care Unit at Queen Sirikit National Institute of Child Health between November 2011 and October 2012. Subjects and Methods: Children aged 1 month to 18 years who were ventilated >48 h were enrolled. Patients were randomized to be ventilated with a disposable or nondisposable heated wire ventilator circuit. Statistical Analysis Used: Statistical analysis was performed using SPSS version 17.0. The P < 0.05 was considered statistically significant. Results: Ninety-eight patients were enrolled. Of these, 48 were administered the disposable ventilator circuit, whereas 50 were administered the nondisposable ventilator circuit. The VAP rate was 20.53/1000 ventilator days for the former (n = 7) compared to 30.77/1000 ventilator days (n = 12) for the latter (odds ratio: 1.85; 95% confidence interval: 0.66–5.19, P = 0.24). The mortality rates were 2.1% in the disposable and 12% in the nondisposable circuit groups (P = 0.06). The unit cost of the disposable circuit (US dollar [USD] 51.60) was higher than that of the nondisposable circuit (USD 37.90). However, the total cost for the nondisposable group was higher due to the required use of more units (63 circuits for the disposable group vs. 95 circuits for the nondisposable group). Conclusions: The type of ventilator circuit is not likely to affect the VAP rate and mortality in children. The unit cost of a disposable circuit is higher than that of a nondisposable circuit. The total cost depends on the number of circuits used in each patient.

Anesthetic management in Charcot-Marie-Tooth disease type 2 due to a mutation in the mitofusin-2 gene

Sir, Charcot-Marie-Tooth disease (CMT) is a neuromuscular disorder characterized by length-dependent degeneration of the motor and sensory nerve fibers, with a prevalence of 1 in 2,500 (about 200,000 patients in the European Union). Anesthesia is administered on this population more frequently than on normal people, as CMT patients often need orthopedic surgery to correct muscle imbalance and limb deformities, and for osteo-synthesis of bone fractures as they are prone to falls. Good anesthetic management in such patients includes prevention and prompt treatment of potential, although rare, complications such as malignant hyperthermia; awareness of prolonged responses to neuromuscular blocking drugs and toxicity caused by inappropriate doses in case of severe muscle wasting; and avoidance of a medication-induced exacerbation of neuropathy.[1–4] CMT is a genetically heterogeneous disorder, but so far, anesthesiology literature has never considered the patients′ gene mutations; and many studies not even the CMT type; though the occurrence of these complications might depends on the genetic defect. We recently administered anesthesia to a patient with a mutation (Arg280His) in the gene that encodes for mitofusin-2, a large and ubiquitously expressed mitochondrial transmembrane protein required for mitochondrial fusion.[5] The 73-year-old woman underwent anesthesia for two different surgical procedures (umbilical hernioplasty; transvaginal hysteroannexiectomy) at a 22-month interval. She elicited a history of severe lower-limbs sensory worsening with loss of independent ambulation after epidural anesthesia for hip osteo-synthesis, performed three years earlier. We chose a totally intravenous anesthesia for both procedures.[6] Propofol and fentanyl intravenous were used for induction and maintenance; lungs were ventilated using disposable circuits and a ventilator unpolluted by volatile anesthetics, with a mixture of air and oxygen. Atracurium was administered to facilitate intubation and for neuromuscular blockade, in the first intervention. Temperature was monitored using an esophageal thermal probe. Dantrolene was kept available. At the end of the surgical procedures, neuromuscular blockade was reversed with atropine and prostigmine. After the first intervention, on recovering ability to follow verbal commands, trachea was extubated. However, during the postoperative period, the saturation fell to 80% as a result of hypopnea/apnea, and the patient was mechanically ventilated for 2½ hours. After the second intervention too, the patient had severe hypoventilation and was mechanically ventilated for about 10 hours. This is the first report of anesthetic management of a patient with a mutation in the mitofusin-2 gene, the most common cause of axonal CMT (CMT type 2A-2). Further research is necessary to understand whether the mitofusin-2 pathology plays a role in delaying the adequate recovery of spontaneous breathing. We suggest that the possibility of developing this complication be considered when dealing with patients affected with this form of CMT.

Use of a Multi-modality Life Support System

The purpose of this study was to describe the design and utilization of a multi-modality life support system (MMLSS), which is used to provide extracorporeal support for cases such as left heart bypass (LHB), extracorporeal life support (ECLS), veno-venous bypass, and hypothermic resuscitation. The design of the MMLSS consisted of a mobile cart outfitted with a centrifugal pump, heater cooler, an in-line blood gas monitor, oxygen blender/flow meter, and assorted safety devices (pressure sensors and level and bubble detectors). A single disposable circuit was used for all procedures and designed to be easily modifiable to support a variety of clinical scenarios, with and without the use of an oxygenator. The system was designed for rapid deployment throughout the hospital. From January 1, 2006 to December 31, 2007, the MMLSS has been used in three LHB procedures (63 ± 72 minutes), four adult ECLS cases (57.2 ± 56.9 hours), four veno-venous bypasses (72 ± 35 minutes), and one hypothermic resuscitation (182 minutes). The MMLSS was designed to be used in patients &gt;20 kg and could achieve flows in the range of 1-5.5 L. There were no complications associated with the device. The MMLSS is a versatile system that can be used throughout the hospital with a single disposable circuit, accommodating a diverse caseload in a safe and reproducible manner.

Intensive care in the developing world

Appropriate and sustainable intensive care practice is possible even in the resource-limited locations of sub-Saharan Africa. Data from seven sub-Saharan African countries indicates that the majority of patients served are surgical. Comparison between intensive care units is difficult due to lack of laboratory support, which precludes the severity sickness scores used internationally. Hospital mortality can be reduced by increasing nurse/patient ratios, adequate monitoring and initiating postoperative intermittent positive pressure ventilation when required. Equipment should include appropriate technology, for instance using oxygen concentrators and a ventilator not dependent on compressed gases or disposable circuits. The clinical officer anaesthetist has a major role to play in the intensive care team.

Disposable Breathing Circuit Tubing as a Safety Sleeve

Disposable Breathing Circuit Tubing as a Safety Sleeve

Three cases of breathing system malfunction

Three cases of breathing system malfunction

Three cases of breathing system malfunction

Three cases of breathing system malfunction

Peripherally inserted veno-venous ultrafiltration for rapid treatment of volume overloaded patients

Background: Veno-venous ultrafiltration may benefit patients with acute or chronic circulatory volume overload. Use of conventional systems, however, may be cumbersome, requiring physician placement of a double-lumen central venous catheter and use of a dedicated dialysis technician and apparatus. Methods: A simplified peripheral ultrafiltration system including a miniaturized disposable circuit was evaluated in patients with volume-overload states. Separate intravenous catheters (16-18 G) for withdrawal and return of blood (blood flow ≤ 40 mL/min, ultrafiltrate ≤ 500 mL/h) were placed by nonphysician personnel in upper extremity veins. Twenty-five treatments of up to 8 hours were performed in 21 patients. Results: The primary endpoint of greater than 1 L fluid removal in less than 8 hours was achieved in 23 of 25 treatments. On average, 2611 ± 1002 mL (maximum 3,725 mL) of ultrafiltrate was removed per treatment (treatment period 6:43 ± 1:47 hours:minutes). Patient weight decreased from 91.9 ± 17.5 to 89.3 ± 17.3 kg (P <.0001) after ultrafiltration. No major adverse events occurred. Conclusions: Rapid removal of extracellular and intravascular fluid volume excess can be safely achieved via peripherally inserted ultrafiltration without the need for central venous catheter placement.

Early techniques of extracorporeal circulation.

While the techniques and equipment used 50 years ago may seem primitive by today's standards, they did permit cardiac surgery to rapidly develop. As early as 1951, Karlson would write: 'Recent advances in surgery have made operations upon the heart much more than surgical stunts, and have opened a hitherto relatively untouched field of surgical endeavor. A few years later, Mustard would defend his abysmal series of repairs of congenital cardiac defects by saying, 'Our techniques of perfusion and operation have proved feasible in three human cases, but the results are not adequate to operate freely on good-risk patients at the present time. It is hoped that improvements in techniques will soon make this possible'. By the end of the decade of the 1950s. Gross would express the following: In the support of human patients on pump oxygenators, the intricacies of technic are many, and the extent of problems is broad, but much clarity of thought is now evident. We can set forth certain statements considered to represent truths or valuable viewpoints, since in most cases they have derived from scores of laboratory experiences during which some 800 dogs have been used by us, or else they have been crystallized from bitter experience at the operating table, or shattering disappointments in postoperative failures. Fortunately, many of the conclusions have sprung from happy and rewarding results exhibited by patients who have weathered corrective surgery in a very satisfactory manner. In closing, after reviewing the early perfusion literature, it is evident that many techniques used in the 1930s, 1940s, and 1950s persist to the present. Some techniques fell out of favor, such as elective hyperkalemic arrest, only to be re-established decades later. Simplicity is the hallmark of the most enduring techniques, a thought expressed by Lillehei in 1955. Somewhat amazingly, full automation of the extracorporeal circuit existed on some of the very early machines, but perhaps because of the explosive growth of cardiac surgery and the need for disposable circuits that could be rapidly assembled, the safety aspects of heart-lung machines were neglected for many decades. Some would argue it still has not realized its potential for elimination of error in the conduct of cardiopulmonary bypass. However, cardiac surgery would not wait, and in 1956, Osborn would boldly state: 'Extracorporeal circulation for surgery of the heart has now come of age.

Leakage of disposable breathing circuits

Study Objective: To determine the sites and rates of the leakage of disposable breathing circuits. Design: Nonclinical, experimental study. Setting: Experimental laboratory. Interventions: To identify in vitro the leakage sites by bubble test and to measure the leakage rate by the increased oxygen (O 2) flow needed to maintain the circuit pressure provided by an anesthesia machine previously verified to have no leaks. Breathing circuit pressures measured with a sphygmomanometer of 30, 50, 70, and 100 mmHg were studied. Measurements and Main Results: Ninety-seven disposable and three reusable breathing circuits from seven manufacturers were investigated for leakage. There was a linear relationship between the circuit pressure and O 2 fl ow at which leaks occurred. No leakage was detected in reusable circuits at 30 mmHg of circuit pressure. Leakage was found in two of the six junctions between the patient adapter and the corrugated tubing in the reusable breathing circuits at a circuit pressure of 100 mmHg. In 90% of the disposable circuits tested, the leakage rate was less than 75 ml/min at 30 mmHg of circuit pressure, but there was a wide variation in the amount of leakage among the circuits of different companies. Almost all the leakage sites were located at connections in the circuit and not in the corrugated tubing. The most common site of leakage in the disposable circuits was the junction between the patient adapter end and the corrugated tubing (57%) rather than the swivel piece (40%). Conclusions: Most disposable breathing circuits can be used safely for closed-circuit anesthesia, as the leakage volume is too small to be of clinical importance. The variation in the leakage rates stresses the importance of quality control of the connector seals.

Microbial burdens in disposable and nondisposable ventilator circuits used for 24 and 48 h in intensive care units.

One hospital sought to study the differences in using resterilizable permanent versus disposable ventilator circuits and changing the circuits on a 24-h versus a 48-h basis. Over a period of 13 months 656 condensate samples from 92 permanent and 72 disposable circuits were collected and plated by a loop dilution technique. Two samples were collected from the inspiratory limb (humidifier; tubing or nebulizer), and two were collected from the expiratory limb (tubing and trap) of each circuit. Contamination rates were higher for disposable circuits than for permanent circuits and for 48-h changes than for 24-h changes. Results of chi 2 testing by site indicated there was more contamination on the inspiratory and expiratory limbs each with use of disposable circuits than with the use of permanent circuits. The total results (chi 2 analysis) showed significantly greater microbial growth with the use of disposable circuits (permanent versus disposable, P less than 0.001) and extension of time to 48-h changes (24 h versus 48 h, P less than 0.05). In the experience of this hospital permanent circuits proved more advantageous from the standpoint of contamination risk and cost.

Microbiological assessment of 24- and 48-h changes and management of semiclosed circuits from ventilators in a neonatal intensive care unit.

The contamination of semiclosed disposable circuits of Healthdyne and Bourns ventilators was studied in a newborn intensive care unit over a 2-year period. A total of 379 fluid samples was obtained from inspiratory and expiratory tubing condensates and traps and from thermal humidifier columns fed with prefilled containers of sterile water. In addition, 100 tryptic soy agar plates were exposed to the exhalation mist of the circuits sampled. With 24-h changes of circuits a 2.5% contamination rate was observed (phase I). In an effort to contain costs, circuits were changed every 48 h (phase II); the concentration of potential pathogens increased to greater than 10(5) CFU/ml with this extension of changing time. Two long-term (15- and 9-month) infants were colonized and intermittently infected, one with Klebsiella pneumoniae and Staphylococcus aureus and the other with Pseudomonas aeruginosa. When the protocol was readjusted from 48- to 24-h circuit changes (phase II), the contamination rate decreased; for the two colonized infants (35 circuits, 123 samples) the contamination rate decreased from 19 to 6% (P less than 0.01; chi-square test), and for seven noncolonized infants (59 circuits, 217 samples) the contamination rate decreased from 5 to 0.5% P less than 0.001; (chi-square test). These data suggest that frequent changing of the circuits reduces colonization and cross-infection.

Disposable anesthetic circuit

Disposable anesthetic circuit

TECHNIQUE OF REFRIGERATED COIL PRESERVATION HAEMODIALYSIS WITH FEMORAL VENOUS CATHETERIZATION.

The use of daily haemodialysis in the treatment of severe acute renal failure has resulted in a significant improvement in mortality rates : 75 % of patients with acute hypercatabolic renal failure survived (Teschan et al., 1960). More recently Murray et al. (1961), using continuous haemodialysis, obtained 80% survival rates in similar patients. However, these results were obtained with MacNeill-Collins (MacNeill et al., 1959), Skeggs-Leonards (Skeggs and Leonards, 1948), or modified Kiil (1960) dialyser, which require considerable technician-time in assembling and are not available in most haemodialysis units. To overcome these problems, and to provide an efficient dialyser for daily haemodialysis at an economic rate which would be available in most renal centres, we have modified the Kolff twin coil kidney (Kolff and Watschinger, 1956) and disposable circuit to permit repeated use of the disposable dialyser without extra blood requirements. In addition, the entire assembly and running of the dialyser can now be performed by trained nursing staff without any supervision by a physician.