Preoperative Red Cell Distribution Width and 30-day mortality in older patients undergoing non-cardiac surgery: a retrospective cohort observational study.

Increased red cell distribution width (RDW) is associated with poorer outcomes in various patient populations. We investigated the association between preoperative RDW and anaemia on 30-day postoperative mortality among elderly patients undergoing non-cardiac surgery. Medical records of 24,579 patients aged 65 and older who underwent surgery under anaesthesia between 1 January 2012 and 31 October 2016 were retrospectively analysed. Patients who died within 30 days had higher median RDW (15.0%) than those who were alive (13.4%). Based on multivariate logistic regression, in our cohort of elderly patients undergoing non-cardiac surgery, moderate/severe preoperative anaemia (aOR 1.61, p = 0.04) and high preoperative RDW levels in the 3rd quartile (>13.4% and ≤14.3%) and 4th quartile (>14.3%) were significantly associated with increased odds of 30-day mortality - (aOR 2.12, p = 0.02) and (aOR 2.85, p = 0.001) respectively, after adjusting for the effects of transfusion, surgical severity, priority of surgery, and comorbidities. Patients with high RDW, defined as >15.7% (90th centile), and preoperative anaemia have higher odds of 30-day mortality compared to patients with anaemia and normal RDW. Thus, preoperative RDW independently increases risk of 30-day postoperative mortality, and future risk stratification strategies should include RDW as a factor.

Interparticle forces in spherical monodispersed silica dispersions: effects of branched polyethylenimine and molecular weight.

The effect of branched polyethylenimine (PEI) of molecular weight (Mw) 600, 1800 and 70,000 on the surface forces interacting between 'uniform size' spherical silica particles in water was investigated via the yield stress and zeta potential techniques. This silica has a point of zero charge at pH approximately 2.0. All PEIs caused the zeta potential-pH curve and the high pH zero zeta potential to shift to a higher pH and the extent of the shift increases with increasing PEI concentration and is not affected by PEI Mw. PEI adsorption on silica is low or negligible at pH less than 3.5 and this is due to a very low negative charge density. Adsorption of PEI beyond 3.5 caused a maximum zeta potential to occur at pH between 4 and 6. The maximum yield stress located at the point zero zeta potential is many times larger than that with no added PEI. It ranged from 20 to 42 times for low Mw PEI and as high as 68 times for Mw 70,000. At low surface coverages, the force responsible for the high yield stress is charged patch-bridging attraction. At complete surface coverage, particle bridging via hydrogen bond and unlike charged attraction between monomeric, dimeric and tetrameric silicate ions with the adsorbed PEI layers of the interacting particles was responsible.

Does computer-assisted surgical navigation total knee arthroplasty reduce venous thromboembolism compared with conventional total knee arthroplasty?

INTRODUCTION: The study aims to show that total knee arthroplasty using computer-assisted surgical navigation without intramedullary rodding is safer than conventional intramedullary techniques in preventing venous thromboembolism. METHODS: 30 patients were grouped into groups of 10. Groups A and B had conventional intramedullary rodding of the femur and/or tibia. Group C had no rodding of the femur and tibia using computer-assisted surgical navigation. The degree, duration and size of the embolic shower were captured by a transoesophageal echocardiography probe. The echogenic emboli were graded according to the Mayo Clinic score. Haemodynamic parameters such as pulse oximetry oxygen saturation, end-tidal carbon dioxide, heart rate and mean arterial pressure were also recorded. RESULTS: There was a significant difference in the size of the emboli and the Mayo Clinic score when comparing the groups with intramedullary rodding and those without. There was also a significant difference in the pulse oximetry oxygen saturation and heart rate when the group without intramedullary rodding was compared with groups with rodding. CONCLUSION: Surgical navigation total knee arthroplasty may be safer than conventional total knee replacement with intramedullary rodding in preventing venous thromboembolism.

A comparison of 5% dextrose in 0.9% normal saline versus non-dextrose-containing crystalloids as the initial intravenous replacement fluid in elective surgery.

Intravenous fluid replacement in adult elective surgery is often initiated with dextrose-containing fluids. We sought to determine if this practice resulted in significant hyperglycaemia and if there was a risk of hypoglycaemia if non-dextrose-containing crystalloids were used instead. We conducted a randomized controlled trial in 50 non-diabetic adult patients undergoing elective surgery which did not involve entry into major body cavities, large fluid shifts, or require administration of >500 ml of intravenous fluid in the first two hours of peri-operative care. Patients received 500 ml of either 5% dextrose in 0.9% normal saline, lactated Ringer's solution, or 0.9% normal saline over 45 to 60 minutes. Plasma glucose, electrolytes and osmolarity were measured prior to infusion, and at 15 minutes and one hour after completion of infusion. None of the patients had preoperative hypoglycaemia despite average fasting times of almost 13 hours. Patients receiving lactated Ringer's and normal saline remained normoglycaemic throughout the study period. Patients receiving dextrose saline had significantly elevated plasma glucose 15 minutes after completion of infusion (11.1 (9.9-12.2, 95% CI) mmol/l). Plasma glucose exceeded 10 mmol/l in 72% of patients receiving dextrose saline. There was no significant difference in plasma glucose between the groups at one hour after infusion, but 33% of patients receiving DS had plasma glucose > or = 8 mmol/l. We conclude that initiation of intravenous fluid replacement with dextrose-containing solutions is not required to prevent hypoglycaemia in elective surgery. On the contrary, a relatively small volume of 500 ml causes significant, albeit transient, hyperglycaemia, even in non-diabetic patients.

Postoperative nausea and vomiting: a review of current literature.

INTRODUCTION: Postoperative nausea and vomiting (PONV) is one of the commonest complaints following anaesthesia, and can result in morbidity like wound dehiscence, bleeding, pulmonary aspiration of gastric contents, fluid and electrolyte disturbances, delayed hospital discharge, unexpected hospital admission, and decreased patient satisfaction. METHOD: A literature search was done on the Medline and relevant articles chosen. RESULTS: Despite the vast amount of research done in this field and the variety of antiemetic drugs available, PONV still has a high incidence. Many factors are associated with PONV. Quantifying the relative impact of risk factors on PONV has resulted in the development of risk models, which can stratify risk categories and hence allow the anaesthetist to identify those patients at higher risk for PONV. The management of PONV requires a multi-modal approach which can include the use of less emetogenic anaesthetic techniques, balanced analgesia, appropriate intravenous hydration, the use of pharmacotherapy and possibly non-pharmacologic methods. CONCLUSIONS: The use of risk models facilitates the judicious use of pharmacotherapy to ameliorate PONV especially in the high-risk patient and may lead to a more cost effective and efficient means of managing PONV.

Thermal capsular shrinkage: Basic science and clinical applications.

Recently, the use of thermal energy to shrink the redundant glenohumeral joint capsule in patients with instability has generated a great deal of interest. Proponents assert that the procedure avoids the need for an open stabilization and it may be used as an adjunct to an open or arthroscopic capsulolabral repair. The use of nonablative thermal energy to shrink soft-tissue collagen appears to induce ultra-structural and mechanical changes at or above 60 degrees C. The microscopic changes reflect the unwinding of the collagen triple helix and loss of the fiber orientation. The fibrils contract into a shortened state and reactive fibroblasts have been shown to grow into this treated area and synthesize the collagen matrix. The biomechanical properties of the tissue do not appear to be detrimentally altered if shrinkage is limited to less than 15% and if ablation or excess focal treatment is avoided. The endpoint of optimal shrinkage is not known and clinical estimations of tissue changes and volumetric reduction are used as guides to treatment. The first clinical follow-up study was only recently published in the peer-reviewed literature and prior preliminary reports were optimistic regarding the use of thermal energy for the treatment of glenohumeral instability. Thermal capsular shrinkage has been used as an adjunct to a capsulolabral repair, as well as an isolated treatment for the disorders of internal impingement and multidirectional instability. Additional evaluation is necessary to determine the optimal quantity of energy needed for tissue shrinkage without inadvertent tissue destruction. The long-term clinical effect, mechanical properties, and durability of the newly produced collagen need to be analyzed further. The basic science and clinical applications of this newly applied technology are reviewed in this article.

Achilles tendon surgery: S-shaped surgical approach and postoperative positioning to minimize wound tension and external pressure.

For Achilles tendon surgery, an S-shaped incision may be made crossing the midline proximal to the transverse skin creases above the top of the heel counter. This incision provides wide exposure of the tendon and enables wound closure with minimal skin tension. After surgery, direct external pressure on the wound and dependent swelling of the Achilles tendon region, which may increase risks for wound dehiscence and infection, are minimized by laying the patient in the lateral decubitus or prone position to elevate the heel.

Acute patellar tendon rupture: A new surgical technique.

The most common method used in the treatment of acute patellar tendon ruptures is primary end-to-end repair. The use of the Acufex ACL guide (Acufex Microsurgical, Mansfield, MA) provides efficient and accurate placement of transosseous drill holes in the patella and minimizes the risk, tourniquet time, and surgical time of acute patellar tendon repairs.

Fall incidence in a state psychiatric hospital in Singapore.

The results of a retrospective study of fall incidence during a 1-year period in a psychiatric hospital in Singapore are reported, involving 309 patients who fell one or more times during their stay. The profile of inpatients involved in falls was identified. Data were derived from standard incident forms completed whenever patients had a fall. A total of 348 falls were identified for the 1-year period. Results revealed higher fall rates in younger male epileptic patients; elderly female patients, age 70 and older with depression or dementia; individuals with concomitant medical conditions; and patients taking three types of medication. The majority of falls occurred when the activity level was high in the ward. Young epileptic patients and elderly depressed patients were prone to repeated falls. These results have the potential to assist in identifying patients at high risk and in designing and implementing strategies to prevent such incidents.

Long-term follow-up of the one-bone forearm procedure.

The one-bone forearm procedure can be a successful salvage option for forearm stability in selected patients and is indicated if instability and bone loss are irreparable by other means. We report a case of a dysfunctional arm secondary to radical débridement of the ulna after osteomyelitis treated successfully with a one-bone forearm procedure and followed up for 8 years.

Changing the institutional practice of prolonged mechanical ventilation after coronary artery bypass graft surgery to early extubation.

Since 1997 some of our cardiac anaesthetists have, whenever possible, extubated the patients early after cardiac surgery to improve their level of comfort, to allow an early return of the cardiopulmonary physiological function, and to help reduce health care costs. After a few months of implementing this practice, an audit was carried out to evaluate the success of early extubation after coronary artery bypass graft (CABG) surgery. Over a 6-month period starting from May 1997, the perioperative data of 110 consecutive patients with good or moderate left ventricular function scheduled for elective CABG were prospectively collected and analysed. The anaesthetic regime was according to the preference of the anaesthetists. Initially consent was obtained from the surgeons when the extubation criteria were fulfilled, but subsequently as the practice became more accepted by the surgeons, extubation was initiated by the anaesthetists. Within 4 hours of admission into the intensive care unit (ICU), 50 (45.5%) of the 110 patients satisfied the early extubation criteria and were extubated. The extubation criteria are described in the article. For the remaining patients, the median duration of mechanical ventilation was 14.3 hours. The profiles of the two groups of patients and the possible reasons for not extubating early are discussed. Forty-five per cent of the patients with moderate to good ventricular function were extubated safely within 4 hours of admission into the ICU after CABG surgery. With gradual acceptance of the practice and a change in mindset amongst all the care givers, more patients can benefit from this practice. This article highlights the challenges associated with changing institutional practices with respect to the postoperative care of cardiac patients.

Cesarean section in a mother with uncorrected congenital coronary to pulmonary artery fistula.

PURPOSE: We report a case of a 33 yr old woman with pulmonary hypertension secondary to uncorrected right coronary artery to pulmonary artery fistula who underwent two successful operative deliveries under general anesthesia. CLINICAL FEATURES: This woman underwent an emergency Caesarean section at 32 wk gestation because she presented in NYHA Class IV, heart failure and premature labour. She did not have antenatal follow-up. For her second pregnancy, she was managed from the first trimester of pregnancy by the cardiologist, obstetrician and anesthesiologist. She received oral furosemide and digoxin from eight weeks gestation. Pregnancy was managed to term before she progressed to NYHA Class IV and cardiac failure at 37 wk gestation. She had a Caesarean section under general anesthesia. She received rapid sequence induction of anesthesia and tracheal intubation with 0.1 mg x kg(-1) etomidate, 2 mg x kg(-1) succinylcholine and maintenance with nitrous oxide 50% in oxygen, isoflurane 1% and 0.1 mg x kg(-1) vecuronium. Fentanyl, 2 microg x kg(-1) helped to obtund the hypertensive response to intubation. Analgesia was provided with 1 mg x kg(-1) morphine. Glyceryl trinitrate infusion, 10-30 microg x min(-1) was used in addition to the anti-heart failure therapy. End-tidal capnography, electrocardiogram, pulse oximetry, continuous arterial blood pressure and pulmonary arterial catheter provided hemodynamic monitoring. The lungs were mechanically ventilated for 24 hr postoperatively. She received anti-heart failure therapy which she continued after discharge. She was NYHA class II upon discharge. She defaulted from further follow-up. CONCLUSION: Although the literature advocates, in this situation, controlled vaginal delivery utilising epidural analgesia, we describe the successful outcome for operative delivery under general anesthesia in a patient with secondary pulmonary hypertension and heart failure.