Anesthesia protocol for ear surgery in Wistar rats (animal research)

ObjectiveTo formulate an anesthesia protocol for safe and satisfactory anesthesia for ear surgery in rats.MethodsThe rats were anesthetized with xylazine (10 mg/kg body weight) and ketamine at doses of 80, 50, 40, and 30 mg/kg body weight or with isoflurane anesthesia (2%–3.5% in 100% oxygen; maintenance dose 1.5%–3.5%). The anesthesia induction, surgery, and recovery time were recorded.ResultsIn total, 17 rats were induced by varying doses of ketamine‐xylazine and 28 rats with isoflurane. Mean induction time with ketamine‐xylazine was 6 ± 2.9 min compared with 3.8 ± 1.1 min with isoflurane. Mean recovery time with ketamine‐xylazine was 142.6 ± 49.3 min compared with 4.1 ± 1.2 min with isoflurane. A mortality of 4 animals after developing dyspnea was recorded with ketamine‐xylazine.ConclusionIsoflurane anesthesia offers appropriate induction and recovery times and low mortality rates for the surgeries performed. Isoflurane anesthesia offers reliable results for ear surgery in rats. However, more equipment and technical skills are needed.     

Acute Dieldirin Toxicity: Biochemical Changes in the Blood

The effect of a single sublethal dose of dieldrin on values for plasma corticosterone (free), nonesterified fatty acids, blood glucose, glucose tolerance, blood pyruvic acid, blood lactic acid, and liver lactic acid has been investigated. The blood glucose level is elevated and glucose tolerance is lowered, Indicating an impairment in the utilization of glucose. A significant increase is observed in the levels of other constituents. A correlation of these effects with adrenocortical activity has been attempted.     

Olecranon fractures: factors influencing re-operation

Purpose

We evaluated factors influencing re-operation in tension band and plating of isolated olecranon fractures.

Methods

Four hundred eighty-nine patients with isolated olecranon fractures who underwent tension band (TB) or open reduction internal fixation (ORIF) from 2003 to 2013 were identified at an urban level 1 trauma centre. Medical records were reviewed for patient information and complications, including infection, nonunion, malunion, loss of function or hardware complication requiring an unplanned surgical intervention. Electronic radiographs of these patients were reviewed to identify Orthopaedic Trauma Association (OTA) fracture classification and patients who underwent TB or ORIF.

Results

One hundred seventy-seven patients met inclusion criteria of isolated olecranon fractures. TB was used for fixation in 43 patients and ORIF in 134. No statistical significance was found when comparing complication rates in open versus closed olecranon fractures. In a multivariate analysis, the key factor in outcome was method of fixation. Overall, there were higher rates of infection and hardware removal in the TB compared with the ORIF group.

Conclusions

Our results demonstrate that the dominant factor driving re-operation in isolated olecranon fractures is type of fixation. When controlling for all variables, there is an increased chance of re-operation in patients with TB fixation.     

Adjacent segment degeneration in the lumbar spine

BACKGROUND: A primary concern after posterior lumbar spine arthrodesis is the potential for adjacent segment degeneration cephalad or caudad to the fusion segment. There is controversy regarding the subsequent degeneration of adjacent segments, and we are aware of no long-term studies that have analyzed both cephalad and caudad degeneration following posterior arthrodesis. A retrospective investigation was performed to determine the rates of degeneration and survival of the motion segments adjacent to the site of a posterior lumbar fusion. METHODS: Two hundred and fifteen patients who had undergone posterior lumbar arthrodesis were included in this study. The study group included 126 female patients and eighty-nine male patients. The average duration of follow-up was 6.7 years. Radiographs were analyzed with regard to arthritic degeneration at the adjacent levels both preoperatively and at the time of the last follow-up visit. Disc spaces were graded on a 4-point arthritic degeneration scale. Correlation analysis was used to determine the contribution of independent variables to the rate of degeneration. Survivorship analysis was performed to describe the degeneration of the adjacent motion segments. RESULTS: Fifty-nine (27.4%) of the 215 patients had evidence of degeneration at the adjacent levels and elected to have an additional decompression (fifteen patients) or arthrodesis (forty-four patients). Kaplan-Meier analysis predicted a disease-free survival rate of 83.5% (95% confidence interval, 77.5% to 89.5%) at five years and of 63.9% (95% confidence interval, 54.0% to 73.8%) at ten years after the index operation. Although there was a trend toward progression of the arthritic grade at the adjacent disc levels, there was no significant correlation, with the numbers available, between the preoperative arthritic grade and the need for additional surgery. CONCLUSIONS: The rate of symptomatic degeneration at an adjacent segment warranting either decompression or arthrodesis was predicted to be 16.5% at five years and 36.1% at ten years. There appeared to be no correlation with the length of fusion or the preoperative arthritic degeneration of the adjacent segment.     

The study of fecal-Escherichia coli peritonitis-induced septic shock in a neonatal pig model

Peritonitis-induced septic shock in the neonate is associated with a high mortality. Because there exists no clinically relevant model to study resuscitation of these patients, a model using the neonatal pig was developed. After arterial and central venous cannulation, and placement of a left pulmonary-artery thermodilution catheter, 12 anesthetized neonatal pigs were "resuscitated" with fluids (5% albumin in lactated Ringer's solution at 15 ml/kg/hr), antibiotics, and correction of acidemia. The pigs were divided into two groups: a control group (n = 5), which was not subjected to peritonitis and which was killed after 6 hours of monitoring, and a septic group (n = 7), which was inoculated with an intraperitoneal injection of sterile pig feces and Escherichia coli and was monitored until death (mean survival time (S.D.) 546(159) minutes). Serial measurements of hemodynamic and laboratory data were obtained. While pigs in the control group showed no significant changes in these data as measured against time, the pigs in the experimental group showed an early transient rise in cardiac index which was significant (p less than .05) and which was followed by a steady decline in cardiac index until death. These changes in cardiac index were accompanied by a continuous decline in mean arterial pressure, central venous pressure, pulmonary artery pressure, and systemic vascular resistance index, while pulmonary vascular resistance index showed a gradual continuous rise. The observed changes in hemodynamic and laboratory data mimic those anticipated in the human neonate with peritonitis-induced septic shock. This model proves reliable and reproducible, and shows promise as a tool to study the resuscitation of neonates with septic shock.