Risk factors for laryngospasm in children during general anesthesia

Background:  Laryngospasm is a common and often serious adverse respiratory event encountered during anesthetic care of children. We examined, in a case control design, the risk factors for laryngospasm in children.
Material and Methods:  The records of 130 children identified as having experienced laryngospasm under general anesthesia were examined. Cases were identified from those prospectively entered into the Mayo Clinic performance improvement database between January 1, 1996 and December 31, 2005. Potential demographic, patient, surgical and anesthetic related risk factors were determined in a 1 : 2 case–control study.
Results:  No individual demographic factors were found to be significantly associated with risk for laryngospasm. However, multivariate analysis demonstrated significant associations between laryngospasm and intercurrent upper respiratory infection (OR 2.03 P  =   0.022) and the presence of an airway anomaly (OR   =   3.35, P  =   0.030). Among those experiencing laryngospasm during maintenance or emergence, the use of a laryngeal mask airway was strongly associated even when adjusted for the presence of upper respiratory infection and airway anomaly ( P  =   0.019). Ten patients experienced postoperatively one or more complications whereas only three complications were observed among controls ( P  =   0.008). No child required cardiopulmonary resuscitation and there were no deaths in either study cohort.
Conclusions:  In our pediatric population, the risk of laryngospasm was increased in children with upper respiratory tract infection or an airway anomaly. The use of laryngeal mask airway was found to be associated with laryngospasm even when adjusted for the presence of upper respiratory tract infection and airway anomaly.     

Paediatric surgery carried out by general surgeons: a rural New Zealand experience

Background: There are increasing moves towards centralization in paediatric surgery. With only four paediatric tertiary centres in New Zealand, many general surgeons still routinely carry out paediatric surgery. We present an audit of paediatric surgical patients admitted to our general surgical unit. Methods: Data were prospectively recorded using a standardized pro forma on all children aged 15 years and below, who presented to general surgery between 11 December 2005 and 11 December 2006. Results: There were 209 admissions (194 children); the median age was 8 years (range 6 weeks to 15 years) with 153 (73%) acutes. Male : female ratio was 3:2 and 37 children (18%) were less than 2 years of age. Procedures (n = 119) comprised appendicectomy (35), inguinal herniotomy (30), skin procedures (29), endoscopy (10), testicular (10) and others (5). The commonest acute and elective operations were appendicectomy and inguinal herniotomy, respectively, with 51% of all operations carried out acutely. There were 10 tertiary hospital transfers (5%) for burns (4), pyloric stenosis (3), intussusception (1), neonatal inguinal hernia (1) and pyoderma gangrenosum (1). Median age of transfers was 11 months (range 6 weeks to 14 years). Complications were wound infection (1), postoperative ileus (2) and infarcted ovary (1). Conclusion: A large number of children presented to our surgical department. Approximately half required surgery and half of the operations were acute. There is still a significant need for general paediatric surgery in the provinces and hence close collaboration with specialist paediatric surgeons.     

Excess lipid availability increases mitochondrial fatty acid oxidative capacity in muscle: evidence against a role for reduced fatty acid oxidation in lipid-induced insulin resistance in rodents

A reduced capacity for mitochondrial fatty acid oxidation in skeletal muscle has been proposed as a major factor leading to the accumulation of intramuscular lipids and their subsequent deleterious effects on insulin action. Here, we examine markers of mitochondrial fatty acid oxidative capacity in rodent models of insulin resistance associated with an oversupply of lipids. C57BL/6J mice were fed a high-fat diet for either 5 or 20 weeks. Several markers of muscle mitochondrial fatty acid oxidative capacity were measured, including (14)C-palmitate oxidation, palmitoyl-CoA oxidation in isolated mitochondria, oxidative enzyme activity (citrate synthase, beta-hydroxyacyl CoA dehydrogenase, medium-chain acyl-CoA dehydrogenase, and carnitine palmitoyl-transferase 1), and expression of proteins involved in mitochondrial metabolism. Enzyme activity and mitochondrial protein expression were also examined in muscle from other rodent models of insulin resistance. Compared with standard diet-fed controls, muscle from fat-fed mice displayed elevated palmitate oxidation rate (5 weeks +23%, P < 0.05, and 20 weeks +29%, P < 0.05) and increased palmitoyl-CoA oxidation in isolated mitochondria (20 weeks +49%, P < 0.01). Furthermore, oxidative enzyme activity and protein expression of peroxisome proliferator-activated receptor gamma coactivator (PGC)-1alpha, uncoupling protein (UCP) 3, and mitochondrial respiratory chain subunits were significantly elevated in fat-fed animals. A similar pattern was present in muscle of fat-fed rats, obese Zucker rats, and db/db mice, with increases observed for oxidative enzyme activity and expression of PGC-1alpha, UCP3, and subunits of the mitochondrial respiratory chain. These findings suggest that high lipid availability does not lead to intramuscular lipid accumulation and insulin resistance in rodents by decreasing muscle mitochondrial fatty acid oxidative capacity.     

Chondrocyte viability after intra-articular calcaneal fractures in humans

BACKGROUND: Chondral damage from the impact of injury may contribute to the high incidence of post-traumatic arthritis after calcaneal fractures, but this has yet to be proven. We sought to study the effect of intra-articular calcaneal fractures on chondrocyte viability and to correlate these effects with injury severity, time from injury to surgery, and patient age and co-morbidities. METHODS: Irreducible osteochondral fragments from 12 patients undergoing operative treatment for intra-articular calcaneal fractures were analyzed. Control cartilage was obtained from four tissue donors who died of unrelated causes. The cartilage was assessed for chondrocyte viability through the full thickness of tissue using a Live/Dead assay followed by laser scanning confocal microscopy. Patient demographics including injury classification and severity, time from injury to surgery, and patient age were recorded. RESULTS: Chondrocyte viability from fracture patients averaged 72.8% +/- 12.9% (range 53% to 95%), which was significantly lower than the 94.8% +/- 1.5% viability observed in the control specimens (p = 0.005). Chondrocyte viability declined with higher energy injuries (p = 0.13), time from injury to surgery (p = 0.07), and increasing patient age (p = 0.07). However, none of these factors reached a level of statistical significance. CONCLUSIONS: A significant decline in chondrocyte viability occurs after intra-articular fractures of the calcaneus. This may contribute to the development of post-traumatic arthritis.     

Pain after percutaneous radiofrequency ablation of renal tumors

BACKGROUND AND PURPOSE: Most patients have minimal pain after percutaneous radiofrequency ablation (RFA) of a renal tumor. However, anecdotally, there is some variation in the amount of patient discomfort. Our goal was to identify relevant patient factors and characteristics of their renal tumors that may influence pain after percutaneous RF ablation. PATIENTS AND METHODS: We performed a retrospective chart review of 59 sequential patients who received percutaneous RFA between 2001 and 2005 at a single institution. Data on patient age, sex, body mass index (BMI), and narcotic administration in the periprocedural period were available for 46 patients. Preoperative imaging (CT or MRI) was reviewed to determine tumor size and location, as well as the shortest distance of the mass to the body-wall musculature. RESULTS: The distance from the renal mass to the body-wall musculature was significantly correlated with the total narcotics received in the periprocedural period. This measured distance did not correlate with the patient's BMI. No other relations between patient factors or tumor characteristics and peri-procedural narcotic usage were identified. CONCLUSION: Patients whose tumors lie close to their body-wall musculature have greater narcotic requirements in the periprocedural period. Knowledge of this correlation should result in better patient counseling and help anticipate periprocedural analgesia requirements.     

Fracture risk after parathyroidectomy among chronic hemodialysis patients

The impact of parathyroidectomy (PTX) on the long-term risks for hip and other fractures is unknown. Uncontrolled case series have reported an increase in bone mineral density after PTX. However, very low serum parathyroid hormone levels have been associated with decreased bone mineral density, adynamic bone disease, and fractures. This study compared long-term fracture rates among hemodialysis patients who underwent PTX with a matched control group. Data were obtained from the US Renal Data System. Patients who underwent a first PTX while receiving hemodialysis were matched with up to three control patients by age, race, gender, year of dialysis initiation, primary cause of renal failure, and the dosage of intravenous vitamin D used before PTX. Patients with a history of fracture or renal transplantation were excluded. Study outcomes were incident hip, vertebral, and distal radius-wrist fractures identified using hospitalization codes. Incident hip fracture rates in the PTX and matched control groups were 6.0 and 9.3 fractures per 1000 person-years, respectively. After adjustment, PTX was associated with a significant 32% lower risk for hip fracture (95% confidence interval 0.54 to 0.86; P = 0.001) and a 31% lower risk for any analyzed fracture (95% confidence interval 0.57 to 0.83; P < 0.001) compared with matched control subjects. Fracture risks were lower among hemodialysis patients who underwent PTX compared with matched control subjects. Surgical amelioration of secondary hyperparathyroidism may outweigh the risk of parathyroid hormone oversuppression in terms of bone health.     

Primary localized amyloidosis of the bladder: experience with dimethyl sulfoxide therapy

PURPOSE: We present our long-term experience with intravesical dimethyl sulfoxide (DMSO) for primary localized amyloidosis of the bladder. MATERIALS AND METHODS: The study included 4 males and 2 females 28 to 68 years old (mean age 54) at diagnosis of biopsy proven primary localized amyloidosis involving the bladder diffusely or extensively in 1 locale. All patients had normal upper urinary tracts. They continued to be symptomatic (hematuria in 3, irritative voiding symptoms in 1, and hematuria and irritative voiding symptoms in 2) despite conventional transurethral destructive therapy. Every 2 weeks they received 30-minute instillations of 50 ml. 50% DMSO intravesically for 3 months (patient 1), 6 months (1) and 1 year (4). RESULTS: Therapy failed at 3 and 6 months in 2 patients of whom 1 with a contracted bladder underwent cystectomy and another was stabilized for 1 year with laser therapy. In the remaining 4 patients who were followed for 6 years disease stabilized for 2 to 6 years (mean 3.5) but 3 later required additional therapy including repeat DMSO in 1 and laser therapy in 2. CONCLUSIONS: Diffuse or locally extensive bladder involvement by primary localized amyloidosis usually fails to respond to conventional transurethral destructive surgical procedures. Collectively, our experience and the literature suggest that intravesical DMSO can be a bladder saving measure and help resolve ureterovesical obstruction in some patients. High recurrence rate mandates lifelong cystoscopic surveillance.