Murine TMJ loading causes increased proliferation and chondrocyte maturation

The purpose of this study was to examine the effects of forced mouth opening on murine mandibular condylar head remodeling. We hypothesized that forced mouth opening would cause an anabolic response in the mandibular condylar cartilage. Six-week-old female C57BL/6 mice were divided into 3 groups: (1) control, (2) 0.25 N, and (3) 0.50 N of forced mouth opening. Gene expression, micro-CT, and proliferation were analyzed. 0.5 N of forced mouth opening caused a significant increase in mRNA expression of Pthrp, Sox9, and Collagen2a1, a significant increase in proliferation, and a significant increase in trabecular spacing in the subchondral bone, whereas 0.25 N of forced mouth opening did not cause any significant changes in any of the parameters examined. Forced mouth opening causes an increase in the expression of chondrocyte maturation markers and an increase in subchondral trabecular spacing.

Use of esmolol to control bleeding and heart rate during electroconvulsive therapy in a patient with an intracranial aneurysm

Electroconvulsive therapy (ECT) is a commonly used treatment modality for patients with major affective disorders that are unresponsive to pharmacological therapy. While ECT has been shown to be a very safe treatment, it is associated with transient hemodynamic alterations, including hypertension, which are associated with an increased risk of rupture of an intracranial aneurysm. We describe our use of the ultrashort acting beta-blocker, esmolol, for blood-pressure control in a woman with known cerebral aneurysmal disease who required ECT for treatment of recurrent major depression.

Primary fibrinolysis during supraceliac aortic clamping

PURPOSE

An increased incidence of bleeding complications has been observed after supraceliac aortic clamping (SCC). This study was performed to identify possible hemostatic abnormalities that contribute to this problem.

METHODS

A prospective cohort study over a 3-month period was performed by comparing hemostatic parameters in 10 consecutive patients who required elective SCC with those of eight concurrent randomly selected control subjects who required infrarenal clamping (IRC) for abdominal aortic reconstruction. Measures of coagulation, fibrinolysis, platelet function, temperature, hemodilution, and hepatic function were performed at selected times before, during, and after operation.

RESULTS

Aneurysm size, fibrinogen, D-dimers, prothrombin, partial thromboplastin time, platelet counts, bleeding times, hemodilution, and temperature were comparable in both groups. Patients in the SCC group, however, consistently developed a primary fibrinolytic state within 20 minutes after supraceliac clamping, reflected by significantly decreased euglobulin clot lysis times (ECLT; p < 0.0001), elevated tissue plasminogen activator (t-PA) levels (p < 0.0006), elevated t-PA-to-plasminogen activator inhibitor-1 ratios (p < 0.0001), and reduced alpha 2-antiplasmin levels (p < 0.002). SCC produced hepatocellular injury documented by elevations in both aspartate transaminase (p < 0.0001) and lactate dehydrogenase (p < 0.009).

CONCLUSIONS

SCC rapidly induces a primary fibrinolytic state manifested by increased circulating t-PA, reduced alpha 2-antiplasmin, and increased fibrinolytic activator-to-inhibitor ratios. These effects may be a result of hepatic hypoperfusion caused by SCC leading to insufficient clearance of t-PA. Antifibrinolytic agents may be of benefit if bleeding develops after aortic procedures that require supraceliac clamping.

An evaluation of preoperative anxiety in a population of parents of infants and children undergoing ambulatory surgery

We attempted to identify specific predictors of preoperative parental anxiety in a population of parents of healthy infants and children undergoing elective, outpatient surgery. We specifically examined the following factors: age of the child, whether or not the child had previous surgery, whether or not the parents' other children had previous surgery, parental gender, highest level of education obtained by the parent, and whether or not there was prior discussion between the parent and anaesthesiologist. In the immediate preoperative period, a questionnaire (State-Trait Anxiety Inventory) was given to all parents of infants and children presenting for elective, outpatient surgery. Six hundred parents of 417 children, aged two months to 16 years (mean = 4.5 years), participated in the study. They included 388 mothers and 212 fathers. Our results indicate that parents are more anxious when their child is less than one year of age and when it is the child's first surgery. When assessed separately by parental gender, both these factors were significant for mothers but not their fathers. We recommend that, although anaesthesiologists generally tailor their preoperative preparation based upon the best needs of their patients and families, they pay special attention to the groups we have identified which are at increased risk for preoperative anxiety.

The use of capnography for recognition of esophageal intubation in the neonatal intensive care unit

Failure to recognize esophageal intubation can result in severe hypoxia and permanent neurologic injury. Capnography is a standard monitoring modality in the operating room but has not been utilized fully in other environments. We used capnography at the time of endotracheal intubation in the neonatal intensive care unit (NICU) to determine whether capnography could more quickly and accurately identify endotracheal tube position than other clinical indicators of endotracheal tube position. One hundred intubation episodes were studied in 55 neonates. Capnograms were obtained 15 and 120 sec following tube placement. Intubating personnel were blinded to the capnographic data and determined endotracheal tube location (trachea vs. esophagus) by clinical criteria only. The sensitivity and specificity of capnography and clinical examination for identification of tube position were analyzed, and the time required for establishing by clinical confirmation whether the tube was in the trachea or not was compared to that required for capnography. Forty of 100 intubation attempts resulted in esophageal intubation. Capnography correctly identified these errant tube placements in 39 of 40 instances and did so in 1.6 sec (SD +/- 2.4). Capnography failed to identify successful endotracheal intubation on only one occasion. Clinical indicators of tube position required 97.1 sec (SD +/- 92.6) to identify an esophageal intubation and failed to identify successful endotracheal intubation in 5 of 60 cases. We conclude that capnography is a valuable adjunct to clinical examination to demonstrate whether an endotracheal tube is placed correctly in the trachea of neonates in the NICU.