Volume Of Aspirate Research Articles

Reducing the risk of fatal and disabling hypoglycaemia: a comparison of arterial blood sampling systems

In 2008, the National Patient Safety Agency (NPSA) published a report after 42 incidents and two deaths where glucose-containing flush solutions were attached to the arterial line. The molar concentration of 5% glucose is 277 mmol litre(-1). Only a tiny amount of sample contamination will lead to an artificially high glucose. As the NPSA sought a solution, a bench model was constructed to compare the performance of three open and three closed arterial line systems in limiting sample contamination. All arterial line systems were set up in a standard manner and pressurized to 300 mm Hg with 5% glucose used as the flush solution. This was connected to the 'radial artery' using an 18 G needle representing the radial cannula. The radial artery was simulated using a wide-bore extension set with 'blood' flow at 60 ml min(-1). Blood was simulated by the addition of red dye to Hartmann's solution. Increasing multiples of arterial line dead space were aspirated and discarded. Blood samples were then obtained and glucose concentration was measured. Significant glucose contamination (3 mmol litre(-1) +/-3.4) was detected in all open arterial line systems up to an aspiration volume of five times the dead space. No samples from the closed systems recorded glucose concentration >1 mmol litre(-1). Recommended minimal discard volumes are inadequate in the presence of glucose as the flush solution and can lead to high blood glucose readings, inappropriate insulin use, and iatrogenic neuroglycopaenia. Our study demonstrates that the closed-loop arterial sampling system could be the universal solution sought by the NPSA.

Polymerase Chain Reaction

The article very well written and clinically important, but why did the author not mention the option of using polymerase chain reaction (PCR) as a diagnostic tool? PCR is not a universal diagnostic miracle weapon, but when it works it does so within just a few days and is highly specific. Another advantage is that it can be performed using minimal volumes of aspirates, etc. Even if the procedure was not used in the specific case presented in the article it should have been evaluated in the discussion. The same holds true for both the disease and the test: They need to be borne in mind.

The Assessment of Oropharyngeal Dysphagia in Adults

The Assessment of Oropharyngeal Dysphagia in Adults

Optimization of silicone urinary catheters for hypospadias repair

We have experienced difficulty with the removal of all-silicone Foley catheters after hypospadias repair, relating to the formation of a 'cuff' of residual balloon material that fails to deflate, after aspiration of the instilled volume of water. This could potentially lead to both short- and long-term complications (stenosis, fistula). In all-silicone paediatric catheters, we investigated the production of such 'cuffs', and any other significant deformity which may be associated with deformation of the catheter balloon mechanism, in vitro. Catheters were inflated with 0 (control) to 7 mL of sterile water. The catheter balloon dimensions were measured before and after incubation of the catheters for 168 h in a solution simulating human urine. The aspiration volumes were recorded. At volumes greater than 40% of the manufacturer's advised inflation volume, a significant increase in the transverse diameter of the catheter occurred after deflation, compared to controls (P<0.001). We advise the maximum instillation of 2 mL of water into a 5-mL paediatric catheter balloon to avoid cuff formation. Using this technique allows all of the advantages of a stent, in combination with the security of a catheter, but with a reduced risk of trauma and complications associated with catheter removal.

The effect of bone marrow aspiration strategy on the yield and quality of human mesenchymal stem cells

Introduction Large inter-donor differences exist in human mesenchymal stem cell (hMSC) yield and the response of these cells to osteogenic stimuli. The source of these differences may be clinical differences in stem cell characteristics between individuals or the aspiration procedure itself.Methods From a total of 23 donors, we aimed to take 2 consecutive 10-mL aspirates from the same site in 17 donors and in 6 donors we aimed to take a 5-mL and a 20-mL aspirate. The aspiration was stopped either when the syringe was full or when no more bone marrow came through. Mononuclear cell yield (MNC), MSC yield, and differentiation capacity were analyzed for intra-donor and inter-donor variation. We analyzed the effect of the dilution with peripheral blood by drawing 20 mL at once.Results There was a high correlation between the first and second aspiration volumes, and aspirates with a volume of less than 8 mL showed a large variation in cellular yield. The second 10-mL aspirate, and also 20-mL aspirates, contained a lower concentration of nucleated cells and yielded lower numbers of mesenchymal stem cells. No effect of the aspiration procedure on the biological characteristics of the mesenchymal stem cells was seen.Conclusion We recommend collection volumes of bone marrow aspirates of at least 8 mL to reduce the risk of obtaining aspirates with low cell numbers. From the same site, a second aspiration or an aspirate of > 10 mL can be drawn without any loss of biological quality due to dilution with peripheral blood.

Incremental Diagnostic Yield of On-site Quick-prep Smear versus Cell-block Cytology in EUS-FNA of Solid and Cystic Masses

Purpose: In many centers that perform a high volume of endoscopic ultrasound-fine needle aspiration (EUS-FNA), cytology from both on-site quick prep smears (QPS) and from a centrifuged cell-block (CB) are evaluated. The additive value of performing both instead of one of these tests, however, has not been well studied. The aim of this study is to evaluate the independent diagnostic performance of QPS and CB in specimens obtained from EUS-FNA, and to assess the incremental yield of each test. Methods: A retrospective review was conducted of all EUS-FNA procedures performed at a tertiary referral hospital between August 2006 and July 2008. Procedures in which either QPS or CB was not performed were excluded. All FNAs were performed using a 22 gauge needle (Cook Medical, Bloomington IN). Mass location and size, number of needle passes, cytology adequacy and diagnosis from both QPS and CB were recorded. Diagnoses were categorized as non-neoplastic, atypical, and neoplastic. Data were analyzed with Student's t-test and Chi-Square test where appropriate. Results: Specimens from 442 EUS-FNA procedures met the inclusion criteria and were evaluated. 306 masses were solid (70% pancreatic, 30% other) and 136 were pancreatic cysts. The mean patient age was 65 and the mean mass size was 2.8 cm. The overall diagnostic yield of EUS-FNA (i.e., percentage of procedures in which cytology was adequate to make a diagnosis) was 76.5%, but differed significantly between solid and cystic masses (88.2% vs. 50%, P < 0.0001). When examined independently, the diagnostic yield of QPS did not differ from CB (72.6% vs. 70.1%). For all masses diagnosed as neoplastic based on EUS-FNA, the sensitivity of QPS was significantly greater than CB (97.3% vs. 92.4% P<0.05). In 59 (13.4%) of the 442 cases, the diagnosis between QPS and CB was discordant. In this group, QPS was more likely to make an additional diagnosis (36 cases, incremental yield 8.1%) than CB (23 cases, incremental yield 5.2%; P<0.05). This difference was seen only in solid but not cystic masses. Conclusion: On-site quick prep smears (QPS) from EUS-FNA specimens are more sensitive for diagnosing neoplasia than cell block (CB) and provide a higher incremental diagnostic yield, highlighting the importance of this practice. Prospective studies evaluating the incremental cost effectiveness of processing the CB in the setting of a diagnostic QPS should be considered.

Aspiration Risk After Esophagectomy

To the Editor: A 59-yr-old patient required general anesthesia for extensive dental extractions. Six weeks earlier he had undergone Ivor Lewis esophagectomy and was currently tolerating multiple small meals. The patient was appropriately nulla per os and full stomach precautions were not felt necessary. Immediately after induction there was a large volume bilious regurgitation and aspiration. The patient developed a right upper lobe consolidation and acute respiratory distress syndrome. After a period of mechanical ventilation, the lung injury resolved and he recovered fully. Our literature search revealed only several letters describing the risk of aspiration in patients after esophagectomy.1,2 Standard textbooks include gastroparesis as a risk for aspiration but do not specifically mention prior esophagectomy.3,4 Esophagectomy results in excision of the lower esophageal sphincter and loss of vagal innervation of the stomach. The new gastroesophageal anastomosis is made in the midesophagus (Ivor Lewis) or cervical esophagus (transhiatal). The denervated stomach requires a pyloroplasty to prevent gastric outlet obstruction. The flaccid stomach, draining only by gravity, is in a thoracic position without the protection of a lower esophageal sphincter. Options for management include preinduction placement of a nasogastric tube to decompress the stomach, induction with the patient in the head-up position, rapid sequence induction with cricoid pressure, and awake tracheal intubation. Insertion of a nasogastric tube carries a risk of anastomotic disruption but can be safely placed 2–3 wk postoperatively if the patient is tolerating oral feeding. Although used routinely, cricoid pressure has never been definitively shown to decrease aspiration.5 The stated goal of cricoid pressure is to occlude the cervical esophagus by compressing it between the cricoid ring and vertebral bodies. Radiologic studies in normal volunteers have demonstrated that this does not reliably occur.6 Furthermore, in patients with a cervical anastomosis, the esophagus may be lateral rather than posterior to the cricoid cartilage. Survival is improving for patients with esophageal cancer and anesthesiologists can expect to encounter more patients with prior esophagectomy. Duncan G. de Souza, MD, FRCPC Cheryl L. Gaughen, MD Department of Anesthesiology University of Virginia Charlottesville, Virginia [email protected]

Safe Limits for Aspirate Volume Under Wet Liposuction

Hypovolemia is a hemodynamic disorder occasionally associated with liposuction. The purpose of this study is to settle a safe limit for the volume of aspirate under wet liposuction relating this volume to body weight. The criteria used to establish this limit were based on the Advanced Trauma Life Support (ATLS). Thirty patients underwent wet liposuction and were submitted postoperatively to a 24-h noninvasive monitoring control of vital signs. Tachycardia (over 100 bpm) and systolic hypotension (below 100 mmHg) were recorded as well as urinary volume and respiratory rate. Hemoglobin, hematocrit, and leukocyte counts were determined preoperatively and also determined 1 and 6 h postoperatively. The volume of aspirate ranged from 1,480 to 3,980 ml (2.6% to 6.9% of body weight). Hemoglobin count decreased around 6 h postoperatively compared to the immediate preoperative period (p<0.0001). An increase of leukocytes was observed around 6 h postoperatively when compared with the preoperative period-nearly 30 min before surgery (p<0.0001). No association was found between hemoglobin or leukocyte counts and volume of aspirate. In 15 patients, tachycardia and/or hypotension were recorded postoperatively. These hemodynamic disorders were associated to volumes of aspirate higher than 5% of body weight. Under wet liposuction, a volume of aspiration not superior to 5% of body weight is proposed as a safe limit. It has been found as a clue to avoid hypovolemia and subsequently the shock. This statement is in agreement with ATLS guidelines.

Rapid detection and profiling of cancer cells in fine-needle aspirates.

There is a growing need for fast, highly sensitive and quantitative technologies to detect and profile unaltered cells in biological samples. Technologies in current clinical use are often time consuming, expensive, or require considerable sample sizes. Here, we report a diagnostic magnetic resonance (DMR) sensor that combines a miniaturized NMR probe with targeted magnetic nanoparticles for detection and molecular profiling of cancer cells. The sensor measures the transverse relaxation rate of water molecules in biological samples in which target cells of interest are labeled with magnetic nanoparticles. We achieved remarkable sensitivity improvements over our prior DMR prototypes by synthesizing new nanoparticles with higher transverse relaxivity and by optimizing assay protocols. We detected as few as 2 cancer cells in 1-microL sample volumes of unprocessed fine-needle aspirates of tumors and profiled the expression of several cellular markers in <15 min.

Circumferential suction-assisted lipectomy for lymphoedema after surgery for breast cancer

The incidence of arm lymphoedema after treatment for breast cancer ranges from 1 to 49 per cent. Although most women can be treated by non-operative means with satisfying results, end-stage lymphoedema is often non-responsive to compression, where hypertrophy of adipose tissue limits the outcome value of compression or massage. This was a prospective study of 37 women with unilateral non-pitting lymphoedema. After initial conservative treatment for 2-4 days, circumferential suction-assisted lipectomy was used to remove excess volume. Limb compression was resumed after surgery with short-stretch bandages, followed by flat-knit compression garments. The mean preoperative excess arm volume was 1399 ml. The total aspirate volume was 2124 ml with 93 per cent aspirate adipose tissue content. After 12 months, the mean reduction in excess volume was 118 per cent. The percentage reduction in excess volume after 12 months was linearly related to the preoperative excess volume but showed no linear relationship with the duration of lymphoedema or surgeon experience. Circumferential lipectomy combined with lifelong compression hose is an effective technique in end-stage lymphoedema after treatment for breast cancer.

The effect of ranitidine versus proton pump inhibitors on gastric secretions: a meta‐analysis of randomised control trials

Aspiration of acid into the lungs is an infrequent but potentially devastating complication of general anaesthesia. Routine practice often includes use of pharmacological agents to reduce gastric volume and increase gastric pH. The aim of this study was to compare the net benefit of proton pump inhibitors with histamine 2 blockers in a meta-analysis. Electronic databases were searched for trials that compared ranitidine vs proton pump inhibitors in their effect on volume and pH of gastric fluid aspirates. We identified nine trials of which seven were suitable for meta-analysis. Pooled outcomes suggest that premedication with ranitidine is more effective than proton pump inhibitors in reducing the volume of gastric secretions (by an average of 0.22 ml.kg(-1); 95% confidence interval 0.04-0.41) and increasing gastric pH (by an average of 0.85 pH units; 95% confidence interval -1.14 to -0.28).

Office‐based sclerotherapy for benign parotid lymphoepithelial cysts in the HIV‐positive patient

To determine the efficacy of sodium morrhuate injection therapy in the control of benign lymphoepithelial cysts of the parotid gland. Retrospective review. The medical records of human immunodeficiency virus (HIV)-positive patients who presented to an indigent care hospital for the evaluation and management of benign lymphoepithelial cysts of the parotid gland are reviewed. Cyst laterality, aspiration and injection volumes, and noted complications were recorded. When applicable, elapsed time between recurrent interventions was recorded. Medical records were available for a total of nine patients who underwent aspiration and injection of 34 cysts. Five of the nine patients required therapy for additional cyst formation an average of 11.8 months after initial intervention. There have been no known instances of facial nerve or parotid gland injury, and the only recorded postprocedure complaints were pain and mild edema. While multiple cysts may arise and serial intervention may be required, we believe that in association with broader clinical experience, the data presented here support aspiration and sodium morrhuate injection as a safe, minimally invasive, and efficacious technique in the treatment of benign lymphoepithelial cysts of the parotid gland in the HIV-positive population.

Reducing gastric secretions—a role for histamine 2 antagonists or proton pump inhibitors in malignant bowel obstruction?

Inoperable bowel obstructions are not uncommon in advanced cancer and are associated with a very poor prognosis. Symptom control includes reducing the frequency of vomiting by prescription of antisecretory medications. The most commonly used agents for this are either hyoscine butylbromide or octreotide. Either histamine 2 antagonists or proton pump inhibitors are sometimes recommended as adjuvants to reduce gastric secretions. The aim of this study was to examine the effects of histamine 2 antagonists and proton pump inhibitors and to objectively compare the effects of one agent over another. Previously, electronic databases were searched for trials that compared ranitidine versus proton pump inhibitors in their effect on volume of gastric aspirates. Seven trials were included in a meta-analysis. Pooled outcomes suggest that both proton pump inhibitors and ranitidine reduce gastric volumes, but the most superior agent is ranitidine, which reduces the volume of gastric secretions by an average of 0.22 ml.kg(-1); 95% confidence interval 0.04 to 0.41. Based on well-conducted studies, objective evidence exists that confirms ranitidine will decrease the volume of gastric aspirates. This forms a sound basis from which to develop further research aimed at improving the care of people with malignant bowel obstructions.

Gastrointestinal symptoms in intensive care patients

Gastrointestinal (GI) problems are not uniformly assessed in intensive care unit (ICU) patients and respective data in available literature are insufficient. We aimed to describe the prevalence, risk factors and importance of different GI symptoms. We prospectively studied all patients hospitalized to the General ICU of Tartu University Hospital in 2004-2007. Of 1374 patients, 62 were excluded due to missing data. Seven hundred and seventy-five (59.1%) patients had at least one GI symptom at least during 1 day of their stay, while 475 (36.2%) suffered from more than one symptom. Absent or abnormal bowel sounds were documented in 542 patients (41.3%), vomiting/regurgitation in 501 (38.2%), high gastric aspirate volume in 298 (22.7%), diarrhoea in 184 (14.0%), bowel distension in 139 (10.6%) and GI bleeding in 97 (7.4%) patients during their ICU stay. Absent or abnormal bowel sounds and GI bleeding were associated with significantly higher mortality. The number of simultaneous GI symptoms was an independent risk factor for ICU mortality. The ICU length of stay and mortality of patients who had two or more GI symptoms simultaneously were significantly higher than in patients with a maximum of one GI symptom. GI symptoms occur frequently in ICU patients. Absence of bowel sounds and GI bleeding are associated with impaired outcome. Prevalence of GI symptoms at the first day in ICU predicts the mortality of the patients.

Care and Patience Needed for Accurate Measure of Gastric Residual Volumes

I read with interest the article by Metheny and colleagues1 in the November 2008 issue. The authors state that ”as much fluid as possible” was withdrawn in order to calculate gastric residual volume (GRV) in the study, but I saw no mention of whether a standardized withdrawal technique was used.Although it may seem simplistic, I have found that a first quick pull of the syringe often suggests that little or no GRV exists. Yet when the syringe is slowly and patiently “nursed” (ie, through gentle aspiration, reinstallation when a vacuum lock is felt, then repeating), one often finds aspirate volumes far greater than initially obtained.

Determination of intralumenal individual bile acids by HPLC with charged aerosol detection

An isocratic HPLC charged aerosol detector (CAD) method was developed, validated, and applied for the determination of individual bile acids in human gastric and duodenal aspirates. The method requires a low volume of aspirates (50-100 microl) and minimal sample pretreatment. A Hypersil BDS RP-C(18) column (250 x 4.6 mm, 5 microm particle size) was equilibrated with a mobile phase composed of methanol-[ammoniun formate 20 mM, formic acid 0.5%, triethylamine 0.2% (pH 3)] 67:33 v/v. Its flow rate was 1 ml/min. The elution times for taurocholate, glycocholate, taurochenodeoxycholate, ursodeoxycholate, glycochenodeoxycholate, cholate, and glycodeoxycholate were approximately 9.9, 16.2, 18.2, 21.3, 31.6, 34.5, and 38.5 min, respectively. Calibration curves in the mobile phase were constructed in the concentration range of 0.5-500 microM. Limits of detection and quantification were in the range of 0.07-0.60 microM and 0.20-1.80 microM, respectively. This method was applied first, in gastric aspirates collected in the fasted state, in which bile acid presence is minimal and, second, in duodenal aspirates collected in the fed state, in which a large number of potentially interfering compounds exists. Intra-day relative standard deviation in fasted gastric aspirates and in fed duodenal aspirates was less than 2.2% and 6.0%, respectively.

“Painless” Bone Marrow Aspiration by Slow Suctioning Does Not Affect Peripheral Blood Contamination of the Specimen: Randomized Prospective Crossover Trials

The pain during bone marrow aspiration (BMA) can be best explained by negative pressure inside the bone marrow cavity. Although most standard textbooks recommend rapid suctioning with high negative pressure to minimize peripheral blood contamination, this technique might be associated with more pain. To date, there is no evidence that rapid suctioning can reduce peripheral blood contamination. To find a technique that reduces pain without loss of specimen quality, we conducted two trials. The first was a randomized, crossover trial comparing slow aspiration with low negative pressure (L method) and rapid aspiration with high negative pressure (H method). To evaluate pain during the procedure, 49 patients with hematological malignancy who required BMA more than once were randomly assigned to receive either the first aspiration by the L method and the second by the H method or vice versa. Under local anesthesia, a 16-gauge BMA needle was inserted into the BM cavity. A 1-mL syringe (L method) or a 30-mL syringe (H method) was used to aspirate 0.5 mL of BM fluid. To ensure accuracy of aspiration volume in the H method, an extension tube was connected between the 30-mL syringe and needle, and clamped by forceps when the aspirated volume reached 0.5 mL. Pain during each procedure was evaluated using a visual analog scale (VAS), verbal descriptor scale (VDS), and McGill pain questionnaire (MPQ). In the first trial, repeated measures one-way analysis of variance design was used for serial measurement of pain, and the one-tailed Wilcoxon's test was used to compare pain between the two groups. The second trial compared aspirate quality between the L and H methods. Sixteen allogeneic transplantation donors (median age, 33.5 years; range, 22 to 62 years), underwent the first puncture of the harvest procedure under general anesthesia. BMA was drawn simultaneously from the right and left posterior iliac crest with a 1-mL and a 30-mL syringe; the aspiration side and syringe size were randomized. Nucleated cell counts (NCC) of the BM specimens were determined by automated hematology analyses. The non-inferiority margin was defined as less than 25% on the basis of the absolute difference of NCC between the L and H methods. In the first trial, 34 of the 49 patients (67%; 21 men and 13 women; median age, 49 years; age range, 17 to 77 years) completed the study and provided VAS, VDS and MPQ score data after two consecutive BMA. Present pain intensity (PPI) score of the MPQ was significantly decreased with L method when compared with H method (median absolute difference 0, P=0.037) (Table 1). VAS score and total pain rating index (PRI) of the MPQ were also lower with the L method (median absolute differences −0.6 and −0.5), although these results did not reach statistical significance. There was no significant ordinal interaction in repeated measurement of any scores except the affective-PRI of the MPQ, which was significantly higher at the first aspiration, regardless of the negative pressure intensity (P=0.024). In the second trial, the geometric mean of NCC with the L method was non-inferior to the mean with the H method (P=0.025) (Table 2). These findings indicated that BMA with low negative pressure tended to be less painful, while maintaining specimen quality. There remains difficulty in evaluating the impact of psychological factors on the results. Nonetheless, on the basis of our results we recommend suctioning slowly with low negative pressure using a small syringe in order to reduce pain during BMA.Table 1L methodH methodP-valuemedian (range)median (range)VDS1 (0 to 3)1 (0 to 3)0.212VAS2.2 (0 to 8.4)3.2 (0 to 9.0)0.055MPQPRI-S3 (0 to 16)4 (0 to 30)0.080PRI-A0 (0 to 7)0 (0 to 9)0.192PRI-E0 (0 to 4)0 (0 to 4)0.414F'RI-M2 (0 to 11)3 (0 to 11)0.093PRI-T6 (0 to 32)7.5 (0 to 53)0.063PPI1 (0 to 4)1 (0 to 5)0.037Table 2L methodH methodP-valueGenomic mean of NCC (×104/μL) (95%IC)6.6 (4.6–9.5)7.8 (5.9– 10.4)0.025

Gastric Residual Volume and Aspiration in Critically Ill Patients Receiving Gastric Feedings

The helpfulness of bedside assessment of gastric residual volume in the prediction of aspiration has been questioned, as has the volume that signals increased risk of aspiration. To describe the association between gastric residual volumes and aspiration of gastric contents. In a prospective study of 206 critically ill patients receiving gastric tube feedings for 3 consecutive days, gastric residual volumes were measured with 60-mL syringes every 4 hours. Measured volumes were categorized into 3 overlapping groups: at least 150 mL, at least 200 mL, and at least 250 mL. Patients were categorized as frequent aspirators if 40% or more of their tracheal secretions were positive for pepsin and as infrequent aspirators if less than 40% of their secretions were positive for pepsin. Gastric residual volumes were compared between the 2 aspiration groups. Approximately 39% of the 206 patients had 1 or more gastric residual volumes of at least 150 mL, 27% had 1 or more volumes of at least 200 mL, and 17% had 1 or more volumes of at least 250 mL. Large-bore tubes identified most of the high volumes. Eighty-nine patients were frequent aspirators. Volumes less than 150 mL were common in both aspiration groups. However, the frequent aspirators had a significantly greater frequency of 2 or more volumes of at least 200 mL and 1 or more volumes of at least 250 mL. No consistent relationship was found between aspiration and gastric residual volumes. Although aspiration occurs without high gastric residual volumes, it occurs significantly more often when volumes are high.

Liquid Aspiration and Dispensing Based on an Expanding PDMS Composite

In this paper, we present the development of active liquid aspiration and dispensing units designed for vertical, as well as lateral, liquid aspiration. The devices are based on a single-use thermally expanding polydimethylsiloxane (PDMS) composite, which allows altering its surface topography by means of individually addressable integrated heaters. Devices are designed in order to create an enclosed cavity in the system, due to locally expanding the initially unstructured composite. This enables negative volume displacement and leads to the event of liquid aspiration. To enable this device functionality, two different techniques of selectively creating permanent PDMS bonds have been developed. One approach utilizes the plasma-assisted PDMS bonding technique, together with a patterned antistiction layer to form reversibly, as well as irreversibly, bonded regions. Another approach utilizes microcontact printing of PDMS curing agent, which serves as a patterned intermediate layer for adhesive bonding. Fabricated prototype devices successfully demonstrated the aspiration and release of liquid volumes ranging from 28 to 815 nL. The devices are entirely fabricated from low-cost materials, using wafer-level processes only and do not require external means for liquid actuation.

Liposuction

ABSTRACTAdvent of the tumescent technique in 1987 has allowed for safe contouring in ambulatory single session liposuction under regional or general anaesthesia. Safety and aesthetic issues define MegaLiposuction to be in Volume in litres of more than 10% of Body weight in Kgs. 870 cases of liposuction were performed between September 2000 and August 2008. In (65%) cases, the total volume of aspirate was greater then 5 liters. (Range: 5 to 25 liters). In 24% cases, the large volume liposuction was combined with a limited or a total block lipectomy. Regional anaesthesia with conscious sedation was preferred except where liposuction was for above the subcostal region (the Upper Trunk, Lateral Chest, Back, Gynaecomastia, Breast, Arms and Face) or when the patient so desired. Tumescent infiltration with Lactated ringer, adrenalin, triamcinalone and hyalase was made in all cases. This approach has clinically shown less tissue edema in the post operative period than when the conventional physiological saline was being used in place of Ringer Lactate. The amount injected varied from 1,000 ml to 12,500 ml depending on the size, site and area. Local anesthetic was included only to the terminal portion of the tumescent mixture while infiltrating the sub-costal regions, or when above costal region was combined with below costal region being anaesthetized with Spinal Anaesthesia. The aspirate was restricted to the unstained white / yellow fat and the amount of fat aspirated did not have any bearing to the amount of solution infiltrated. There was no major complication. Blood transfusion was given only on one occasion when the patient had been on aspirin and had also received Low Molecular weight Heparin intra-operative. The hospital stay ranged from 8 to 24 hours for liposuction as well as for liposuction with a lipectomy. Serous discharge from access sites, sero-sanguinous fluid accumulation requiring drainage were necessitated in less than 10% cases. Minor re-contouring touch ups were requested in 5% cases. Early ambulation was encouraged for mobilization of third space fluid shifts to expedite recovery and to prevent deep vein thrombosis. More than 10% patients were operated on for Liposuction of other areas, after a gap of 7 days to 6 months. Meticulous perioperative monitoring of systemic functions ensures safety in tumescent megaliposuction for the obese and rewarding results can be achieved in a single sitting.