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Atypical ductal hyperplasia diagnosed at stereotactic breast biopsy: improved reliability with 14-gauge, directional, vacuum-assisted biopsy.

PURPOSE: To compare histologic findings of atypical ductal hyperplasia (ADH) at 14-gauge, directional, vacuum-assisted breast biopsy (hereafter, vacuum-assisted biopsy) and at 14-gauge, automated, large-core breast biopsy (hereafter, large-core biopsy) with findings at histologic examination after surgical biopsy. MATERIALS AND METHODS: Nonpalpable breast lesions were diagnosed as ADH at histologic examination after vacuum-assisted biopsy in 88 lesions in seven institutions and after large-core biopsy in 55 previously reported lesions. Histologic findings at subsequent surgical biopsy were compared for the presence of carcinoma. RESULTS: On the basis of histologic findings of carcinoma at surgical biopsy, the diagnosis of ADH was not correct in 26 (48%) of 54 lesions sampled at large-core biopsy and in 13 (18%) of 74 lesions sampled at vacuum-assisted biopsy (Fisher exact test, P < .0004). More tissue specimens were obtained at vacuum-assisted biopsy (mean, 15.8 specimens) than at large-core biopsy (mean, 9.7 specimens). Individual specimens were twice as large at vacuum-assisted biopsy (mean, 34 mg) as at large-core biopsy (mean, 17 mg) (previously reported). CONCLUSION: ADH was diagnosed 2.7 times more reliably at vacuum-assisted biopsy than at large-core biopsy (with no increase in complications) with most of the improvement as a result of acquisition of more than 10 specimens per lesion, but carcinoma was sufficiently underestimated with both methods to necessitate surgical biopsy.

Biopsy, Needle↗

Biochemical evaluation of vacuum-assisted venous drainage: a randomized, prospective study.

AIMS OF THE STUDY: In this prospective, randomized study, we investigate the potential advantages of vacuum-assisted venous drainage (VAVD), compared to gravitational drainage (GD), in patients undergoing first-time coronary artery bypass graft (CABG) surgery, concerning biochemical markers of organ and blood cell damage. MATERIALS AND METHODS: Seventy-two consecutive patients were randomized into two groups ['Vacuum' (VAVD) n=36; 'Not vacuum' (GD) n=36]. VAVD was achieved using a wall vacuum source and with a suction regulator connected to the vent port of the hardshell venous reservoir. In the VAVD group, we used 28-French venous cannulas, and 36-French in the GD group. In the VAVD group, we measured arterial perfusion flow (APF) and the venous reservoir volume (VRV) with and without vacuum application just after starting extracorporeal circulation (ECC). Six blood samples were drawn at different times before, during and after ECC. Routine blood tests were performed to evaluate hemolysis, and hepatic and renal function. RESULTS: The two groups were similar in terms of preoperative and operative characteristics. There were no significant differences in biochemical markers of organ function or hemolysis between the two groups. In the VAVD patients, platelet count was higher at 24 h after the end of the operation (VAVD 151.77+/-50.28 microl versus Not vacuum 124.93+/-41.60 microl, p=0.028). With the narrower venous cannulas (28-French), only VAVD achieved a satisfactory APF (VAVD 2.35+/-0.38 l/min/m2 versus GD 1.88+/-0.27 l/min/m2, p=0.002), with a larger VRV (VAVD 1091.67+/-421 ml versus GD 808.33+/-284.31 ml, p=0.025). CONCLUSION: Vacuum-assisted venous drainage is a technique comparable to gravitational drainage with regard to hemolysis and organ perfusion. It allows better perfusion flow and heart decompression with smaller venous cannulas. This study suggests reduced platelet consumption with VAVD.

Aged↗

Comparison of fixation of the femoral component without cement and fixation with use of a bone-vacuum cementing technique for the prevention of fat embolism during total hip arthroplasty. A prospective, randomized clinical trial.

BACKGROUND: Acute hypotension, hypoxemia, cardiac arrest, and sudden death are well recognized complications during total hip arthroplasty, and they have been attributed to embolization of fat and bone marrow. An increase in intramedullary pressure in the femur is the most important pathogenic factor for the development of embolic events. Intravasation of fat, bone marrow, and bone debris during the implantation of a femoral component, and the embolization of these elements through the venous system located along the linea aspera and through the metaphyseal vessels, have been demonstrated experimentally and clinically. The purpose of the present study was to compare the effects of fixation of the femoral component without cement with those of fixation with a bone-vacuum cementing technique on the severity of embolic phenomena and cardiopulmonary impairment during total hip arthroplasty. Fixation with a conventional cementing technique was also evaluated as a control. METHODS: Sixty patients (sixty hips) were entered into a prospective, randomized clinical trial. The patients were assigned to one of three groups. Group 1 consisted of twenty patients who had the femoral component inserted without cement, Group 2 comprised twenty patients who had the component inserted with a conventional cementing technique, and Group 3 included twenty patients who had fixation with the so-called bone-vacuum cementing technique. In the hips in Group 3, a suction of -800 millibars (-80,000 pascals) was applied to a proximal drainage cannula placed along the linea aspera and a distal drainage cannula placed in the diaphysis in order to produce a vacuum in the medullary cavity of the femur during the application of cement and the insertion of the stem. Transesophageal echocardiography and hemodynamic and blood-gas analysis were performed during the operation. RESULTS: Severe embolic events (defined as a cascade of fine echogenic particles of less than five millimeters in diameter) were observed in seventeen (85 percent) of the twenty patients during insertion of the stem with use of a conventional cementing technique but in none of the patients who had the stem inserted without cement (p < 0.05). Insertion of the femoral component with the bone-vacuum cementing technique prevented embolic phenomena in all but one patient (5 percent). Arterial oxygen saturation decreased significantly (p < 0.05) from a mean of 99.5 to 92.9 percent after insertion of the stem with a conventional cementing technique, but only slight changes were observed in the patients who had fixation of the component without cement and in those who were managed with the bone-vacuum cementing technique. Intraoperative pulmonary shunt values increased a mean of 24 percent (p < 0.05) when the femoral component was inserted with a conventional cementing technique, but with the numbers available we did not detect a significant change in those values when the component was fixed without cement or when it was inserted with use of the bone-vacuum cementing technique. CONCLUSIONS: The present study showed that severe embolic events and intraoperative pulmonary impairment are common when a femoral component is fixed with use of a conventional cementing technique. The results clearly demonstrated a low risk of embolism during total hip arthroplasty when the femoral component was fixed without cement and when it was fixed with the bone-vacuum cementing technique. The ability of a patient to withstand an embolic event should be considered before fixation of the femoral component with use of a conventional cementing technique is planned.

Aged↗

Cost-effectiveness of stereotactic 11-gauge directional vacuum-assisted breast biopsy.

OBJECTIVE: The purpose of our study was to determine the frequency with which stereotactic 11-gauge directional vacuum-assisted breast biopsy obviated a surgical procedure and to calculate cost savings attributable to that biopsy method. MATERIALS AND METHODS: We retrospectively reviewed 200 consecutive solitary nonpalpable lesions on which stereotactic 11-gauge directional vacuum-assisted breast biopsy was performed. Cost savings were calculated using Medicare reimbursements. Mammograms, histologic findings, and medical records were reviewed. RESULTS: Stereotactic 11-gauge directional vacuum-assisted biopsy obviated a surgical procedure in 151 (76%) of 200 lesions, including 112 (73%) of 154 calcific lesions and 39 (85%) of 46 masses. Reasons for not obviating a surgical procedure in 49 lesions (25%) included recommendation for surgical biopsy in 35 lesions (18%), small carcinomas treated by excision in 10 lesions (5%), and histologic underestimation in four lesions (2%). Stereotactic 11-gauge directional vacuum-assisted biopsy decreased the cost of diagnosis by S264 per case, a 20% ($264/$1289) decrease in the cost of diagnosis compared with surgical biopsy. Of 200 lesions that had stereotactic 11-gauge directional vacuum-assisted biopsy, 106 (53%) would not have been amenable to 14-gauge automated core biopsy because of their small size, their superficial location, or inadequate breast thickness. CONCLUSION: Stereotactic 11-gauge directional vacuum-assisted breast biopsy obviated a surgical procedure in 76% of lesions, yielding a 20% decrease in cost of diagnosis compared with surgical biopsy. Although savings per case are modest, 11-gauge directional vacuum-assisted biopsy expands the spectrum of lesions amenable to stereotactic biopsy, increasing cost savings in the population.

Adult↗

Outcomes after vacuum-assisted deliveries. Births attended by community family practitioners.

OBJECTIVE: To assess success rates, modes of delivery following failure, complications of mothers and newborns, and effect of extractor station and parity on vacuum-assisted deliveries attended by family physicians. DESIGN: Retrospective audit. SETTING: Community hospital. PARTICIPANTS: Thirty-five family physicians providing maternity care. MAIN OUTCOME MEASURES: Complications, parity, and extractor station of 153 vacuum-assisted deliveries from April 1, 2000, to March 31, 2003. RESULTS: Family physicians attempted 153 vacuum deliveries (82 at low station, 71 at outlet station) and had a 94.1% success rate. Of nine failed vacuum deliveries (eight at low station and one at outlet station), four were subsequently delivered by forceps and five by cesarean section. Except for one case of subdural hematoma, complications were few. Nulliparity was associated with six of the nine failed vacuum deliveries. CONCLUSION: Family physicians were usually successful with vacuum-assisted deliveries. Complications were infrequent and rapidly resolved, but one failure, which was followed by a failed forceps delivery and eventual cesarean section, resulted in a serious complication. Low station and nulliparity were associated with failure of vacuum-assisted deliveries.

Adult↗

Cohort study of silastic obstetric vacuum cup deliveries: I. Safety of the instrument.

A prospective study was undertaken to determine the safety of the Silastic vacuum extractor. Between November 1982 and July 1983, a cohort of 84 successful vacuum extractor deliveries was examined, using the next sequential forceps delivery and spontaneous vaginal delivery as controls. In addition to routine neonatal morbidity measures, Scanlon early neonatal neurobehavioral scale and a modified Sarnat encephalopathy staging examination were used to critically assess neurologic functioning; a cranial ultrasound scan was performed to look for intracerebral hemorrhage, and an indirect ophthalmologic examination was done to assess the incidence of retinal hemorrhage. The study yielded no significant increase in maternal vaginal trauma for vacuum extractor versus spontaneous vaginal delivery, but there was a significantly greater incidence for forceps delivery (60%) versus vacuum extractor (25%) and more associated blood loss for forceps delivery (P less than .01). There was no significant increase in neonatal morbidity for vacuum extractor compared with forceps delivery nor in serious morbidity compared with spontaneous vaginal delivery. Specifically, for vacuum extractor versus forceps delivery there was no difference in one- and five-minute Apgar scores, extent of resuscitation, cosmetic injury, jaundice, mean neonatal intensive care unit stay, or incidence of retinal hemorrhage. Notably, there was no mortality related to delivery method, but there were two unrelated deaths. There were no cases of intraventricular or subgaleal hemorrhage on clinical or ultrasound examination, but one stillborn infant, who succumbed to a generalized coagulation defect, had a subarachnoid hemorrhage. Finally, there was no significant difference in Sarnat encephalopathy staging or Scanlon neurobehavioral assessment between spontaneous vaginal, forceps, and vacuum extractor deliveries.(ABSTRACT TRUNCATED AT 250 WORDS)

Apgar Score↗

A.U and G.C base pairs in synthetic RNAS have characteristic vacuum UV CD bands.

The vacuum UV CD spectra of GpC, CpG, GpG, poly[r(A)], poly[r(C)], poly[r(U)], poly[r(A-U)], poly[r(G).r(C)], poly[r(A).r(U)], and poly[r(A-U).r(A-U)] were measured down to at least 174 nm. These spectra, together with the published spectra of poly[r(G-C).r(G-C)], CMP, and GMP, were sufficient to estimate the CD changes upon base pairing for four double-stranded RNAs. The vacuum UV CD bands of poly[r(A)], poly[r(C)], and the dinucleotides GpC and CpG were temperature dependent, suggesting that they were due to intrastrand base stacking. The dinucleotide sequence isomers GpC and CpG had very different vacuum UV CD bands, indicating that the sequence can play a role in the vacuum UV CD of single-stranded RNA. The vacuum UV CD bands of the double-stranded (G.C)-containing RNAs, poly[r(G).r(C)] and poly[r(G-C).r(G-C)], were larger than the measured or estimated vacuum UV CD bands of their constituent single-stranded RNAs and were similar in having an exceptionally large positive band at about 185 nm and negative bands near 176 and 209 nm. These similarities were enhanced in difference-CD spectra, obtained by subtracting the CD spectra of the single strands from the CD spectra of the corresponding double strands. The (A.U)-containing double-stranded RNAs poly[r(A).r(U)] and poly[r(A-U).r(A-U)] were similar only in that their vacuum UV CD spectra had a large positive band at 177 nm. The spectrum of poly[r(A).r(U)] had a shoulder at 188 nm and a negative band at 206 nm, whereas the spectrum of poly[r(A-U).r(A-U)] had a positive band at 201 nm. On the other hand, difference spectra of both of the (A.U)-containing polymers had positive bands at about 177 and 201 nm. Thus, the difference-CD spectra revealed CD bands characteristic of A.U and G.C base pairing. (ABSTRACT TRUNCATED AT 250 WORDS)

Base Composition↗

External vacuum therapy for erectile dysfunction: use and results.

This review assesses the continuing role of noninvasive vacuum therapy as treatment for erectile dysfunction and discusses the action of negative pressure in producing assisted erection. Through recent research in this area has centered on the development of pharmaceutical therapies, vacuum-therapy programs appear to be a consistent long-term option for patients experiencing either chronic or occasional impotence of any etiology. Very little testing is required before the initiation of vacuum treatment, and the overall; clinical success rate is approximately 90%. Significant success has been reported in more difficult patient populations, including those with veno-occlusive disorders and explanted penile prostheses. Vacuum therapy may also be used in conjunction with other therapies to enhance results. Contraindications to the use of vacuum therapy are few and primarily include patients with unexplained intermittent priapism and bleeding disorders. Side effects such as occasional numbness, pain, penile bruising, or petechiae have a low incidence. A recently reported survey of 5,847 vacuum users showed that 83.5% of patients continue to use the device for intercourse as desired. Patients should receive individual instruction in the use of these devices and should expect a learning or practice period to achieve optimal results. As newer treatments for erectile dysfunction gain increasing attention, it should be kept in mind that nearly every patient showing impotence of any degree or duration as well as patients who have failed other therapeutic choices are candidates for vacuum therapy.

Erectile Dysfunction↗

Vacuum-assisted venous drainage in single-access minimally invasive cardiac surgery.

This retrospective study evaluated the influence of vacuum-assisted venous drainage in single-access minimally invasive cardiac surgery. A total of 104 patients who underwent cardiac surgery via minimal access incision were included in this study. Cardiopulmonary bypass was initiated with gravity alone, and vacuum-assisted venous drainage was applied only when the bypass flow was 2.2 l/min/m2 or less. We compared intraoperative variables of the patients to whom vacuum-assisted venous drainage (vacuum group) was applied with those who underwent gravity venous drainage alone (gravity group). In the 13 patients who most recently underwent isolated valve operations without maze procedures, free hemoglobin was measured to evaluate hemolysis. Vacuum-assisted venous drainage was required in 77 (72.6%) patients. Except for a smaller body surface area in the gravity group (P = 0.0118), patient characteristics did not differ significantly between the two groups. Free hemoglobin 60 mins after the beginning of cardiopulmonary bypass was higher in the vacuum group than in the gravity group (21.5 +/- 7.3 vs 11.1 +/- 7.1 mg/dl, P = 0.0284). Operative mortality and morbidity did not differ significantly between the groups. We found vacuum-assisted venous drainage to be a safe, simple, and effective technique in cases of minimally invasive cardiac surgery. However, there is a potential risk of hemolysis and air embolism, as shown in our findings and previous reports.

Blood Loss, Surgical↗

Stabilization of lactate dehydrogenase following freeze thawing and vacuum-drying in the presence of trehalose and borate.

PURPOSE: The purpose of this work was to investigate the effects of trehalose and trehalose/sodium tetraborate mixtures on recovery of lactate dehydrogenase (LDH) activity following freeze-thawing and centrifugal vacuum-drying/rehydration. The storage stability of LDH under conditions of either high relative humidity or high temperature was also studied. METHODS: LDH was prepared in buffered aqueous formulations containing trehalose alone and trehalose/"borate" mixtures. Enzymatic activity was measured immediately following freeze-thawing and vacuum-drying/rehydration processes, and also after vacuum-dried formulations were stored in either high humidity or high temperature environments. Also, glass transition temperatures (Tg) were measured for both freeze-dried and vacuum-dried formulations. RESULTS: The Tg values of freeze-dried trehalose/borate mixtures are considerably higher than that of trehalose alone. Freezing and vacuum-drying LDH in the presence of 300 mM trehalose resulted in the recovery of 80% and 65% of the original activity, respectively. For vacuum-dried mixtures, boron concentrations below 1.2 mole boron/ mole trehalose had no effect on recovered LDH. After several weeks storage in either humid (100% relative humidity) or warm (45 degrees C) environments, vacuum-dried formulations that included trehalose and borate showed greater enzymatic activities than those prepared with trehalose alone. We attribute this stability to the formation of a chemical complex between trehalose and borate. CONCLUSIONS: The high Tg values of trehalose/borate mixtures offer several advantages over the use of trehalose alone. Most notable is the storage stability under conditions of high temperature and high relative humidity. In these cases, formulations that contain trehalose and borate are superior to those containing trehalose alone. These results have practical implications for long-term storage of biological materials.

Borates↗

Intervertebral disk vacuum phenomenon secondary to vertebral collapse: prevalence and significance.

PURPOSE: To evaluate the prevalence of the intervertebral vacuum phenomenon in disks adjacent to vertebral collapses of various causes. MATERIALS AND METHODS: The authors retrospectively studied 310 consecutive patients who had at least one vertebral collapse. The vacuum phenomena were divided into collapse-related (ie, adjacent to a collapse) and degenerative (ie, not associated with a vertebral fracture) ones. Plain radiography was performed in all patients, and, in addition, conventional tomography, computed tomography, and/or magnetic resonance imaging was performed in 175 patients. RESULTS: Collapse-related vacuum phenomena were seen in 15% of patients with plain radiography and in 21% when all of the imaging modalities were considered. They occurred in association with all of the causes of collapse (ie, osteoporosis, multiple myeloma, metastasis, acute trauma, and vertebral osteomyelitis), although the prevalence was lower in association with metastasis or trauma (P = .008). The occurrence of collapse-related vacuum phenomenon was correlated with age (P = .001) and with the coexistence of degenerative disk-related vacuum phenomenon in the same patient (P = .0002). CONCLUSION: Occurrence of a vacuum cleft in disks adjacent to a vertebral collapse is common and appears as the second cause of vacuum phenomenon after degenerative disk disease.

Adult↗

Gastric and colonic oxygen tension measured with a vacuum-fixed oxygen electrode.

A new electrode system for determination of visceral oxygen tension is presented. The system consists of a transcutaneous oxygen electrode (E5242 Radiometer A/S. Copenhagen), which is screwed into a suction ring and fixed to the organ by applying a vacuum. The electrode membrane is then in contact with the organ surface via a fluid layer with a thickness of a few micrometres, without interference from atmospheric air and without mechanical disturbance of the membrane. The electrode system was tested on the gastric and colonic wall in six pigs. As reference, a silicone tonometer was placed subserously beneath the vacuum-fixed electrode. The silicone tonometer was connected to a second transcutaneous oxygen electrode. The tissue oxygen tension was changed by subjecting the animals to various inspiratory concentrations of oxygen and to hypovolaemia. The oxygen tension measured by the vacuum-fixed electrode (PO2vac) was compared with the oxygen tension measured by the tonometer (PO2tono). A good correlation was demonstrated between PO2vac and PO2tono, the correlation coefficient being 0.8619, confirming that the suction-fixed oxygen electrode measures tissue oxygen. The lowest possible vacuum to hold the electrode unit in place was between 4.0 and 6.7 kPa. Provided the measuring time did not exceed 3 min. vacuum had only slight influence on the measured oxygen values. The mean change in PO2vac induced by varying the vacuum from 7 to 26 kPa, and 26 to 7 kPa, was only +0.23 kPa (-1.2 to +1.9) and +0.19 kPa (-0.3 to +1.3), respectively. The mean stabilization time, defined as the time from electrode application until achieving 95% of the equilibration value, was 66 sec (SEM, 3.4 sec) and 57 sec (SEM, 3.0 sec) on the gastric and colonic wall, respectively. The measured values of PO2vac varied significantly between different areas on the gastric wall (p less than 0.001). When several surface measurements were performed throughout the investigated area, the mean oxygen tension approached the oxygen tension measured by the tonometer. It is concluded that the vacuum-fixed electrode constitutes a reliable, easy and, noninvasive method for measurements of the oxygen tension in the gastric and colonic tissue.

Animals↗

Effect of vacuum extraction on umbilical cord blood acid-base measurements.

The objective of this study was to determine whether vacuum extraction is associated with umbilical cord blood acid-base changes when used electively or in the presence of suspected fetal distress. Data from 1,428 patients from a previously published randomized trial of intrapartum electronic fetal heart rate monitoring versus intermittent auscultation were analyzed to identify differences in umbilical cord blood acid-base measurements associated with the elective use of vacuum extraction (patients with duration of second stage of labor 60 min or less) and also in the presence of suspected fetal distress during the second stage of labor. When used electively, vacuum extraction was associated with lower pH (in both umbilical cord artery and vein), lower venous base excess, and higher venous carbon dioxide tension (PCO2), as compared to normal spontaneous vaginal delivery. After correcting for duration of second stage of labor, elective vacuum delivery was significantly associated only with a decrease in cord venous pH and increase in venous PCO2. However, these cord blood acid-base changes were not accompanied by any differences in perinatal morbidity and mortality or in the number of neonates born with acidemia (cord arterial pH < 7.15 or < 7.10). In cases of suspected fetal distress, the use of vacuum extraction was not associated with any detectable cord blood acid-base changes as compared to normal spontaneous vaginal delivery. These data support the continued use of vacuum extraction, especially in cases of suspected fetal distress during the second stage of labor.

Acid-Base Imbalance↗

Effect of vacuum mixing on the mechanical properties of antibiotic-impregnated polymethylmethacrylate bone cement.

Polymethylmethacrylate bone cement, containing either no added antibiotic, 0.5 g of Vancomycin, 1.0 g of Vancomycin, or 1.0 g of Tobramycin, was mixed either in air or a vacuum chamber. Following storage in a water bath at 37 degrees C for 48 h, the specimens were tested in four-point bending. The porosity of the specimens was assessed radiographically, and their antibacterial activity was monitored for 21 days. The bending strength of the vacuum mixed specimens containing no antibiotic was 40% greater than that of similar air-mixed specimens. However, there were no significant differences in the bending strength of either the air- or vacuum-mixed specimens when any of the antibiotic dosages were added. The bending modulus of the vacuum-mixed specimens, containing no antibiotic, was significantly greater than the moduli of all the other specimen groups which did not differ from each other. Vacuum mixing reduced the apparent porosity of the specimens fivefold, and while the addition of antibiotic did not effect porosity of the air-mixed specimens, that of the vacuum-mixed specimens was doubled. Although initial rapid decreases were seen, leaching of antibiotic from the cement and antibacterial activity continued through the 21-day monitoring period.

Biomechanical Phenomena↗

[Abdominal vacuum device with open abdomen].

BACKGROUND: For the treatment of peritonitis or abdominal compartment syndrome, an open abdomen can be required. Because of the high complication rate associated with this method, different technical modifications were developed that are now being applied. Abdominal vacuum-assisted closure is increasingly favoured. We analyse our experience with this device in a distinct group of patients from gastrointestinal cancer surgery. PATIENTS AND METHOD: From June 2003 to December 2005, 36 patients were treated with 151 double-layer abdominal vacuum devices. Indications for applying this device were peritonitis (n = 22), abdominal compartment syndrome (n = 11), and necrotising fasciitis (n = 3). Thirty-four patients gave anamneses of malignoma. RESULTS: Overall, the vacuum therapy treatment lasted a median of 13 days (range 3-48). With it, four enteric fistulas (11%) and four abdominal wall bleedings (11%) occurred. In our patient group, no new intra-abdominal abscesses were observed. Four patients died during treatment with the vacuum-assisted device and four afterward because of multiple organ failure in acute sepsis (in-hospital mortality 22%). Twenty-six patients (72%) underwent direct fascial closure after a median treatment duration of 10 days. Six patients (17%) required synthetic mesh for fascial closure. After a median follow-up of 100 days, two patients developed ventral hernias and two others showed ossification of the scar. CONCLUSION: Compared with other methods of temporary abdominal closure, our experience with the vacuum-assisted device demonstrates its advantages concerning clinical feasibility and the relatively low complication rate. The high rate of direct fascial closure with an acceptable rate of ventral hernias following vacuum-assisted abdominal closure are further benefits of this technique.

Abdomen↗

Birth progression and traction forces developed under vacuum extraction after slow or rapid application of suction.

A vacuum extraction recorder was used to provide an objective measure of the traction forces developed on the fetal head during 120 vacuum extractions. In half of the deliveries the vacuum was gradually and stepwise increased to -0.8 kg/cm2 before traction. In the others, a rapid application of vacuum to the same level was chosen. No significant difference could be recorded in the traction forces developed by the different methods. In fact, once an adequate level of vacuum had been achieved, high degrees of traction could be applied to the suction cup, regardless of the rate at which the vacuum was developed. Furthermore, the number and nature of neonatal complications were not influenced by the method chosen.

Birth Injuries↗

Skull fracture caused by vacuum extraction.

BACKGROUND: The vacuum extractor is being increasingly advocated as the instrument of first choice for assisted vaginal delivery. It is widely believed that the vacuum cup will dislodge before causing serious fetal trauma. CASE: Rotational delivery of a term infant was effected using a vacuum extractor. A 6-cm Malmström metal cup with a paramedian application was in place for 12 minutes. The vacuum pressure developed was 0.8 kg/cm2. Four traction efforts with contractions were required to deliver the fetal head. A neonatal skull x-ray the following day showed a comminuted parietal bone fracture at the vacuum cup application site. Management was conservative, and the infant's neurologic behavior remained normal. CONCLUSION: The vacuum extractor exerts considerable traction force. Fetal skull fracture can result, and its true incidence may be higher than expected, considering that few neonates with normal neurologic behavior undergo skull x-ray.

Adult↗

Phacodynamics: an aspiration flow vs vacuum comparison.

PURPOSE: To compare actual flow and the vacuum necessary to generate that flow for the Advanced Medical Optics Sovereign (Advanced Medical Optics, Santa Ana, California, USA) and the Alcon Legacy (Alcon, Fort Worth, Texas, USA) phacoemulsification machines. DESIGN: In vitro laboratory study. METHODS: Flow was collected and machine indicated vacuum noted from 12 ml/min to 40 ml/min in 2 ml/min steps (20-gauge). Nineteen and 20-gauge tips were also compared. Machine indicated vacuum was converted to actual tip vacuum. RESULTS: Legacy flow (102.4 +/- 3.8% of indicated) was significantly more than Sovereign (96.5 +/- 3.9%; P < .0001). 20-gauge flow was less than 19-gauge flow (96.1% vs 98.6% of indicated, P < .0001). Sovereign had less unoccluded vacuum (70.3 +/- 3.2 mm Hg) than Legacy (89.4 +/- 1.2 mm Hg) at 36 ml/min of flow (P < .0001 for 26 to 36 ml/min of flow). CONCLUSION: There is unoccluded vacuum at the phaco tip of these systems at 14 ml/min, of flow and at 40 ml/min, this was 112.0 mm Hg for the Legacy.

Phacoemulsification↗