The Safety and Efficacy of Antifibrinolytic Therapy in Neonatal Cardiac Surgery

BackgroundNeonates undergoing open-heart surgery are particularly at risk of postoperative bleeding requiring blood transfusion. Aprotinin has attained high efficacy in reducing the requirement for a blood transfusion following a cardiopulmonary bypass, but is seldom studied in the neonatal age group. The aim of this study was to compare the efficacy and adverse effects of aprotinin and tranexamic acid in neonates undergoing open-heart surgery at a single centre.MethodsBetween October 2003 and March 2008, perioperative data of 552 consecutive neonatal patients undergoing open-heart surgery in Children’s Hospital Boston were reviewed. Among them, 177 did not receive antifibrinolytic therapy (Group A); 100 were treated with tranexamic acid only (Group B); and 275 patients received aprotinin with or without tranexamic acid (Group C). Except for antifibrinolytic therapy, the anaesthesiological and surgical protocols remained identical. Postoperative complications and in-hospital mortality were the primary study endpoints.ResultsBody weight and Risk Adjustment for Congenital Heart Surgery (RACHS-1) scores were statistically comparable among the three groups. No statistically significant differences were observed between the duration of hospitalization, chest tube drainage, reexploration for bleeding, and kidney function impairment. In Group C, less blood was transfused within 24 hours than in GroupB. Operative mortality was similar among the three groups.ConclusionNo further risk and kidney injury were observed in the use of aprotinin in neonatal cardiac surgery, aprotinin demonstrated a reduced requirement for blood transfusion compared with tranexamic acid. Our data provide reasonable evidence that aprotinin and tranexamic acid are safe and efficacious as antifibrinolytic modalities in neonatal patients undergoing cardiac surgery.     

A comparison of two methods of infiltration in breast reduction surgery

The superwet technique has been shown in previous studies to dramatically reduce blood loss in breast reduction surgery, compared with standard infiltration. A retrospective chart review of 303 consecutive patients undergoing bilateral breast reduction surgery was undertaken to demonstrate additional differences in complication rate, operative time, or sponge use in the operating room. In this series, 132 consecutive patients received standard infiltration along incision lines (25 cc per breast of 1:100,000 epinephrine), and 171 patients received superwet infiltration with 240 cc per breast of 1:1,000,000 epinephrine. The average operative time was significantly reduced in the superwet group, from 78.5 minutes to 70.7 minutes (p < 0.01 level). The average number of sponges used intraoperatively was also decreased significantly (p < 0.01), from 26 to 20 sponges. Complication rates were equally low in both groups, demonstrating the safety of the superwet technique. In addition to limiting blood loss, the superwet infiltration effectively reduces operative time and sponge use without increasing complications in breast reduction surgery.     

Reducing complications in cervicofacial rhytidectomy by tumescent infiltration: a comparative trial evaluating 678 consecutive face lifts

Tumescent infiltration has been widely used in body-contouring surgery to facilitate dissection and reduce blood loss. Although its use in facial surgery has been suggested, there are presently no comparative studies of its efficacy. The aim of this study was to investigate the long-term outcome in a large series of consecutive face lifts performed with and without tumescence. During a 6-year period, 678 consecutive face lifts were performed: 449 without tumescence and 229 with tumescent infiltration using 200 ml on each side of the face. The spectrum of techniques included the extended superficial musculoaponeurotic system (SMAS) procedure, the lateral SMASectomy, the extended supraplatysmal plane lift, and the cutaneous face lift. Complications, such as hematoma, skin necrosis, alopecia, and scar quality, were compared between groups using Fisher's exact test. The use of tumescent infiltration facilitated dissection, particularly in the neck. Postoperative swelling and bruising were reduced in the tumescent group. In comparisons of major complications between groups, no difference was seen in hematoma rate (p > 0.5), although the incidence of other complications was significantly reduced by tumescent infiltration. Significant reduction was observed in the rate of skin necrosis (p = 0.03), alopecia (p = 0.006), hypertrophic scarring (p = 0.001), stretched scarring (p = 0.003), and scar revision (p < 0.001). This is the first comparative study of tumescent infiltration in facial rejuvenation surgery. Tumescence made dissection easier and significantly reduced the incidence of troublesome complications. The surgical technique and aesthetic implications for rejuvenation surgery are discussed.     

Fluid dynamic models as a guide to determine prosthetic heart valve diameter

The diameter of prosthetic heart valves is usually chosen according to the anatomic annulus size as determined during open-heart surgery. Therefore, this approach does not take into account the dimensional changes induced by heart pathology and surgical procedures. In addition, current practice fails to consider the variations of heart dimensions due to hemodynamic improvement following valve replacement. Here we suggest a method to determine the appropriate prosthesis diameter according to the hemodynamic features of the patient, to its kind of activity, and to the type of prosthesis. Assuming that the pressure drop across a valve can be calculated as delta p = apv 2/2, and considering the variation of blood flow with time and its change induced by frequency, it is possible to obtain the relationship between pressure drop and prosthetic valve diameter. The results obtained with this analytical method have been plotted on diagrams which allow the graphical determination of the proper valve diameter.     

A feasibility study of a filtration type autotransfusion device

This paper describes a feasibility study of a disposable autotransfusion device for blood salvage during surgery. The goal was to concentrate hemolyzed blood at 20% hematocrit to 50% while reducing the plasma free hemoglobin concentration from 10 to 1.5 g/l. The device should have a total membrane area of less than 0.6 m² and should be able to process ten 500 ml blood bags. The processing time for each blood bag should not exceed 5 min. The basic idea was to use several polypropylene hollow fibre plasma filters of 0.1 m² in series with saline addition between them. Since the mean pore size is 0.5μ m, anticoagulant and plasma hemoglobin can pass freely across the membrane and their concentration is reduced by dilution. The process was first modelled using mass balance equations for red blood cells and plasma hemoglobin in order to find the best device configuration (number of filters and dilutions). It was found that a three filter system could theoretically meet the requirements, if the last filter had a larger surface area (0.3 m²). Some experiments permitted us to prove the validity of this model and to define fully the third filtration stage. Finally, it was shown that the treatment of a 500 ml blood bag required three filtration stages (whose surface areas were respectively 0.1, 0.1 and 0.3 m²) and the use of 750 ml of saline solution added between the filters. This configuration also offers the possibility of using a vacuum driving force instead of pumps, so that the device becomes completely disposable.     

The Role of Sympathectomy in the Treatment of Obliterative Peripheral Vascular Disease

The immediate good results of endarterectomy and vascular grafting have pushed sympathectomy into the background as a form of treatment for peripheral obliterative arterial diseases. There are, however, many instances in which the nature of the arterial disease prevents performance of direct arterial surgery. In these cases an increase in circulation to the skin may not only relieve pain and heal ulcers but also, not infrequently, save the limb from amputation or permit a minor rather than a major amputation.A consecutive group of 90 lumbar and cervicodorsal sympathectomies was reviewed. The majority of patients suffered from atherosclerosis; smaller numbers had Buerger''s or Raynaud''s disease. The assessment of patients, selection for surgery, technique of operation, its complications and early results are discussed. There was one death in this series of patients who ranged in age from 17 to 81 years. This study indicates that, although sympathectomy is not a panacea for obliterative arterial disease, neither is it an obsolete procedure.     

Asepsis in the Operating Theatre

In the investigation of several blood stream infections following open-heart surgery, sutures and other material that had been exposed and handled in the sterile field were examined bacteriologically. One hundred and seventy-five open-heart operations were carried out during the study period and a high percentage of the specimens cultured yielded viable staphylococci and diphtheroids. Glove powder, textile fibres, and skin squames were found in the dust that collected in the room during the operations and staphylococci were frequently recovered from this source, and from the floor. Although the air supply to the theatre appeared to be of good quality, it is suggested that air currents within the room had caused dissemination of this foreign material and had probably contributed to wound infections.     

Automated knot tying for fixation in minimally invasive, robot-assisted cardiac surgery

Cardiovascular disease (CVD) is perhaps the most significant worldwide health issue. While open-heart surgery remains the predominant treatment, significant advancements have been made in minimally invasive surgery (MIS) and minimally invasive robot-assisted (MIRA) surgery. MIRA techniques offer many advantages over open-heart procedures and have extended the capabilities of MIS. However, these benefits come at the cost of increased operating times due to time spent tying knots. The additional bypass time limits patient access and is the most significant barrier to the adoption of MIRA techniques. This research seeks to overcome this barrier by designing a device for MIRA cardiac procedures that automates the knotting of sutures. If this task can be automated while ensuring the delivery of high-quality knots, great progress can be made in transforming the field. MIRA cardiac procedures can move from novel procedures performed by a select group of surgeons on a limited pool of patients to a viable alternative available to the majority of patients with CVD. In this research we propose a design for a self-contained device that delivers a locking knot. Results suggest that consistent knots can be delivered at a time savings of 12.5% and 26.4% over manual knots for trained and untrained users of a surgical robot, respectively.     

Diazepam and propofol used as anesthetics during open-heart surgery do not cause chromosomal aberrations in peripheral blood lymphocytes

Diazepam is a benzodiazepine with anticonvulsant, anxiolytic, sedative and muscle-relaxing properties. Many aspects of its toxicity have been investigated, including genotoxic and carcinogenic effects in various model systems. However, it is still unclear whether diazepam is in fact a genotoxic agent. Propofol is a rapid-onset, short-acting intravenous anesthetic agent. It is used widely for the induction and maintenance of anesthesia as well as for long-term sedation in intensive care units. There is limited information in the literature on its genotoxic effects. Both drugs are commonly used as anesthetic in patients undergoing open-heart surgery. Therefore, we investigated the possible genotoxic effects of propofol and diazepam in those patients, using a chromosomal aberration (CA) assay. Peripheral blood samples were collected from 45 patients before induction of anesthesia and at the end of the anesthesia with diazepam or propofol. In Group I (n=24), anesthesia was induced with 0.2 mg kg(-1) diazepam and 10 microg kg(-1) fentanyl. In Group II (n=21), anesthesia was induced with 1 mg kg(-1) propofol and 10 microg kg(-1) fentanyl. Pancuronium bromide (0.1 mg kg(-1)) was administered for skeletal muscle relaxation in both groups. Anesthesia was maintained by diazepam administration at 5 mg kg(-1) in Group I or by continuous propofol administration at 2-4 mg (kg h)(-1) in Group II. All patients received 0.02 mg kg(-1) pancuronium and 5 microg kg(-1) fentanyl boluses at 30-40 min intervals for anesthesia maintenance. Body temperature was controlled during bypass in the two groups. We found that the mean frequency of CAs in both groups before and at the end of the anesthesia were not statistically significantly different. Our analysis also indicated that age, smoking habit and gender were not confounding factors. In conclusion, our results indicate that diazepam and propofol do not exert genotoxic effects in blood cells during open-heart surgery.     

An assay for acidic peptide substrates of protein kinases

The assay of acidic peptides as substrates for protein kinases has not been as easy to perform as testing basic peptides or polypeptides. We have developed a simple, rapid, and cost-effective procedure that allows the design and testing of potential peptide substrates without the constraints imposed by the phosphocellulose filter paper method (the need to incorporate positively charged residues into the peptide sequence). The technique combines the chelation of 32Pi by acid molybdate with PEI-cellulose chromatography. In this way the migration of 32P-labeled Pi, ATP, and protein are impeded while phosphopeptide is eluted in 1.5 ml from a 0.25-ml disposable column. In order to validate the assay we used two angiotensin II analogues as peptide substrates for the protein tyrosine kinase pp60c-src. The assay results using the new procedure were compared to those of the phosphocellulose filter paper technique. We also demonstrated the use of this method to test linear and cyclic peptides that could not be assayed with the phosphocellulose paper technique. This assay will aid those who are attempting to determine the substrate specificity of protein kinases.     

Boronic acid fluorescent sensors for monosaccharide signaling based on the 6-methoxyquinolinium heterocyclic nucleus: progress toward noninvasive and continuous glucose monitoring

The synthesis, characterization, and spectral properties of strategically designed boronic acid containing fluorescent sensors, o-, m-, p-BMOQBA, for the potential detection of tear glucose concentrations when immobilized in plastic disposable contact lenses is described. The new probes, BMOQBAs, consist of the 6-methoxyquinolinium nucleus as a fluorescent indicator, and the boronic acid moiety as a glucose chelating group. A control compound BMOQ, which has no boronic acid group and therefore does not bind monosaccharides has also been prepared. In this paper, we show that structural design considerations of the new probes have afforded for their compatibility within the lenses, with reduced probe sugar-bound pK(a) favorable with the mildly acidic lens environment. In addition, the new probes are readily water soluble, have high quantum yields, and can be prepared by a simple one-step synthetic procedure.     

The Results of Open-Heart Operations Performed on Children

From December 1, 1959, to January 1, 1965, a total of 166 children have undergone 168 open-heart operations at The Children''s Hospital in Winnipeg, Manitoba.While this series is not a large one, the defects encountered include most of those cardiac abnormalities which are amenable to open-heart correction in children.For all operations a Kay-Cross disc oxygenator was employed. In 42 of the 168 operations, hypothermia (25-30° C.) was also used and was obtained by a Brown-Harrison heat exchanger incorporated into the arterial line.The smallest infant survivor in this series of patients weighed 8 lb. 14 oz. at the time of her operation.Of the 166 children operated upon 149 have survived, an overall survival rate of 89.8%.     

Palmar shelf arthroplasty, the next generation: distraction/interposition for rheumatoid arthritis of the wrist

Rheumatoid arthritis affects approximately 1 percent of the adult population. Bilateral symmetric involvement of the wrist occurs in 85 percent of these patients, with recurrent flares and relentless progression. Anatomic changes consist of radiocarpal, intercarpal, and radioulnar subluxation and joint destruction. For advanced disease, both wrist arthrodesis and arthroplasty have been recommended. Arthrodesis has been successful for pain relief at the expense of motion. Implant arthroplasty has been unreliable, with failure rates of 25 to 50 percent at 2 to 9 years. Palmar shelf arthroplasty was introduced in 1970 as a resectional fibrous arthroplasty. The results were good but the series was small. Subsequent reports of this procedure have been inconsistent. In 1990, I initiated and have since followed a series of patients treated with the palmar shelf arthroplasty. To the basic procedure, I added joint distraction by external fixator, collagen/bone wax interposition, scapholunate stabilization, and increased immobilization time. Fourteen consecutive patients were enrolled in this study. Each carried a diagnosis of rheumatoid or psoriatic arthritis of the wrist. There were 11 women and 3 men. Age ranged from 28 to 56 years. Follow-up ranged from 2 to 7 years (average 4.2). The patients were interviewed, examined, and x-rayed. A questionnaire using an analog scale as well as the Hospital for Special Surgery scoring system was completed to assess the clinical outcome of the wrist postoperatively compared with its preoperative status and with the contralateral wrist. No patient has requested or required a revision procedure. All patients experienced improvement with both pain and function; no wrist spontaneously fused. Patient satisfaction was high. Patients with ipsilateral arthroplasty and contralateral arthrodesis preferred the arthroplasty. Hospital for Special Surgery score increased from 53 to 91 out of 100 points (p < 0.001). Range of motion averaged 50 degrees flexion, 30 degrees extension. Palmar shelf arthroplasty remains a viable option for severe rheumatoid disease of the wrist. Ideally, the procedure is performed on the dominant wrist of a patient with bilateral wrist involvement in the setting of inflammatory arthritis.     

Effets de la chirurgie á coeur ouvert sur les mécanismes de défense contre lea infections bactériennes

Extracorporeal circulation during open-heart surgery may damage cellular and humoral factors in the blood. Phagocytic functions of circulating polymorphonuclear leukocytes were investigated in 10 patients 1 day before, then 1 hour, 2, 4 and 10 days after open-heart surgery. Transient diminutions in the phagocytic capacity of polymorphs was found for Staphylococcus aureus and Escherichia coli in one patient, and E. coli only in two patients up to the 4th postsurgical day. A positive correlation was found between the duration of extracorporeal circulation and the transient diminutions in phagocytic capacity for these three patients. However, the bactericidal capacity of polymorphs and their capacity to reduce nitroblue tetrazolium were normal in all patients. The serum concentrations of total hemolytic complement, C3, IgG and IgM were generally diminished up to the 4th day after surgery, but the opsonic power of the serum was almost normal in all the patients.     

Modified tendon stripper for obtaining palmaris longus tendon graft

Tendon graft harvesting is a challenging part of hand surgery. It is not only a time-consuming procedure but also carries the potential complications associated with it. Various alternatives for this procedure are presented in the literature to overcome these difficulties. In this paper, we are presenting a series of cases in which a newly modified tendon stripper was used for tendon graft harvesting.     

CARDIOGENIC ACUTE RENAL FAILURE (CARF) FOLLOWING OPEN-HEART SURGERY

Although previous reports have attributed acute renal failure (ARF) following cardiovascular surgery to acute tubular necrosis (ATN), little emphasis has been placed on renal failure due to congestive heart failure (CARF). Of 100 cases of ARF studied prospectively over an 18-month period, 36 occurred after open-heart surgery. Nineteen of these cases were associated with heart failure. The remaining 17 had ATN as manifested by high urinary sodium, low urine/plasma creatinine, and abnormal urinary sediment. At the onset of CARF, intravascular volume expansion was universally present, and oliguria with pulmonary edema was common. Urinary chemistries were (mean +/- SD): sodium (mEq/L) 8 +/- 7, U/P creatinine 72 +/- 45, and FENa (%) 0.1 +/- 0.1. Therapy consisted of digoxin, furosemide (F), vasopressors (V), and, when indicated, intraaortic balloon counterpulsation. Survivors of CARF responded more frequently to F and required less V. Ultimately, survival depended upon improvement in cardiac performance. All oliguric ATN patients failed to respond to F. Mortality for the CARF group was 52%. In contrast, 82% of the oliguric ATN group expired, whereas overall ATN mortality was 60%. Cardiogenic acute renal failure is a frequent cause of ARF after open-heart surgery in our institution. It is characterized by prerenal urinary chemistries, has a high mortality, and may be reversible.     

A novel system for mild hypothermia

Mild hypothermia has been shown to provide protective effects in patients with ischemia (e.g. acute stroke and heart attack), but traditional methods for inducing, maintaining, and reversing hypothermia are slow, difficult to administer and control, and uncomfortable for patients. An innovative method produces mild, wholebody hypothermia (32 degrees C to 34 degrees C) by use of an endovascular heat exchanger placed into the inferior vena cava. A closed-loop system accurately changes core body temperature with average cool-down rates of 4.8 degrees C per hour, tight-target temperature control of +/- 0.1 degree C, and average rewarm rates of 1.9 degrees C per hour. By enhancing the mixing of blood in the vicinity of the heat exchanger, the disposable, small-diameter catheter efficiently exchanges heat between the closed-loop circulating fluid and the blood stream in response to body temperature. A control algorithm adapts to body physiology and thermal mass to mitigate temperature excursions. Flexible, bellow-shaped segments along the length of the catheter allow precise maneuvering within blood vessels. Heparin, covalently bonded to the catheter, helps control thrombogenicity. This novel design has potential clinical applications in cerebrovascular surgery, acute stroke, acute myocardial infarction, cardiac arrest, and fever control.     

A rapid and sensitive lipase assay using triethylaminoethyl cellulose columns

A procedure has been developed for the separation of labeled fatty acids from tri-, di-, and monoglycerides using small disposable columns of TEAE-cellulose. This procedure is used as the basis of a lipase assay which is rapid, sensitive and unaffected by wide variations in the composition of the reaction mixtures. 0.5 nmole [¹⁴C]oleic acid can be detected, and the entire procedure requires less than 3 min.     

The first 1000 coronary artery repair operations in Toronto

The present status of the aortocoronary bypass procedure is described in general terms by a review of the first 1040 patients who received this operation in Toronto, before November 15, 1973. The operative risk was related to the status of the left ventricular function. In those with fair or good ventricular function the risk of hospital mortality was less than 3% in the entire series and less than 2% in the past year. Advances in investigative and surgical techniques have allowed this operation to become an increasingly safe, effective and recommended procedure for patients suffering from medically intractable angina pectoris. The operation has been of great benefit to such individuals. In addition it has been an effective stimulus to research and development in Canadian cardiology and cardiovascular surgery.     

Lorazepam (Ativan) and fentanyl (Sublimaze) for outpatient office plastic surgical anesthesia

Lorazepam (Ativan) and Fentanyl (Sublimaze) given in small doses during surgery not only achieve excellent intraoperative sedation and patient cooperation, but also significantly reduce recall and recognition of events during the surgery for as long as 3 hours after the surgery. Included is a series of 814 patients in whom this protocol was used between 1981 and 1984 with a 94 percent patient postoperative follow-up. With this protocol there have been no known complications, and patient reactions have been unanimously favorable.