Role of Vitamin D Supplements in Prevention of Hungry Bone Syndrome after Successful Parathyroidectomy for Primary Hyperparathyroidism: A Prospective Study

BACKGROUND

We postulated that the preoperative correction of vitamin D levels can significantly reduce the incidence of hunger bone syndrome among patients undergoing parathyroidectomy for primary hyperparathyroidism.

METHODS

We performed a prospective, randomized, open-label study on 102 patients with primary hyperparathyroidism and coexisting vitamin D deficiency who were scheduled to undergo parathyroidectomy. Patients were divided into the following two groups: group I which included 52 patients who did not receive preoperative vitamin D supplementation; and group II which included 50 patients who received cholecalciferol 1000-2000 IU daily or 50000 IU weekly until they achieve vitamin D levels >20 ng/mL (group IIa = 25 patients) or vitamin D levels >30 ng/mL (group IIb = 25 patients).

RESULTS

The incidence of hunger bone syndrome in group IIb was lower than group I and group IIa (8% versus 16% versus 23%, respectively); however, this difference did not reach the level of statistical significance (p = 0.22). Patients with hunger bone syndrome were significantly younger and had higher serum phosphorus, alkaline phosphatase, magnesium, and bone mineral density at baseline than patients without hunger bone syndrome. On the other hand, patients with hunger bone syndrome had significantly lower 25-hydroxyvitamin D at baseline than patients without hunger bone syndrome (p = 0.001). The ROC curve showed that the baseline level of serum 25-hydroxyvitamin D was not an independent discriminator of hunger bone syndrome (area under curve = 0.21 (95% CI: 0.06-0.34); p = 0.011).

CONCLUSION

Preoperative course of vitamin D supplements has no preventive role on the postoperative incidence of hunger bone syndrome among patients with primary hyperparathyroidism and coexisting vitamin D deficiency undergoing parathyroidectomy.

Approaches for evaluating veterinary epidemiological models: verification, validation and limitations

The evaluation of models of the spread and control of animal diseases is crucial if these models are to be used to inform decisions about the control or management of such diseases. Two key steps in the evaluation of epidemiological models are model verification and model validation. Verification is the demonstration that a computer-driven model is operating correctly, and conforms to its intended design. Validation refers to the process of determining how well a model corresponds to the system that it is intended to represent. For a veterinary epidemiological model, validation would address such issues as how well the model represents the dynamics of the disease in question in the population to which this model is applied, and how well the model represents the application of different measures for disease control. Just as the development of epidemiological models is a subjective, continuous process, subject to change and refinement, so too is the evaluation of models. The purpose of model evaluation is not to demonstrate that a model is a 'true' or accurate' representation of a system, but to subject it to sufficient scrutiny so that it may be used with an appropriate degree of confidence to aid decision-making. To facilitate model verification and validation, epidemiological modellers should clearly state the purpose, assumptions and limitations of a model; provide a detailed description of the conceptual model; document those steps already taken to test the model; and thoroughly describe the data sources and the process used to produce model input parameters from those data.

The effect of ketamine on acute muscular ischaemia reperfusion in rats

BACKGROUND AND OBJECTIVE

The aim of this study was to investigate any possible protective effect of ketamine in acute muscular ischaemia and reperfusion injury by measuring malondialdehyde using thiobarbituric acid assay in rats.

METHODS

Twelve female Wistar albino rats were anaesthetized with chloral hydrate and randomly assigned into two groups to receive ketamine 1 mg kg(-1) min(-1) or saline infusion. Blood and gastrocnemius muscle samples were obtained 10 min after onset of infusion, before ischaemia. Then, femoral arteries were clamped for 30 min. Blood and muscle samples were obtained at the 30th minute of ischaemia and 10 min after reperfusion.

RESULTS

Muscle malondialdehyde concentrations were 27.88 +/- 2.45, 27.62 +/- 3.98 before ischaemia, 32.10 +/- 4.19, 30.77 +/- 2.73 in the 30th minute of ischaemia and 44.34 +/- 2.45, 34.83 +/- 2.78 after reperfusion in saline and ketamine-treated rats, respectively (nmol g(-1), mean +/- SD). The muscle malondialdehyde level after reperfusion was lower in ketamine-treated rats compared to saline group (P < 0.002). Plasma malondialdehyde levels were 3.77 +/- 0.16, 3.78 +/- 0.18 before ischaemia, 3.81 +/- 0.25, 4.00 +/- 0.86 at the 30th minute of ischaemia and 4.00 +/- 0.53, 3.94 +/- 0.95 after reperfusion, respectively, in saline and ketamine-treated rats (micromol L(-1), mean +/- SD). The effect of ketamine on muscular malondialdehyde was not observed in concurrent plasma malondialdehyde levels.

CONCLUSION

Ketamine was found to attenuate acute ischaemia-reperfusion injury in muscle tissue in rats (muscular protective). Ketamine may attenuate lipid peroxidation in muscle tissue in tourniquet-requiring manoeuvres.

Induced hypotension for tympanoplasty: a comparison of desflurane, isoflurane and sevoflurane

BACKGROUND AND OBJECTIVES

This prospective, randomized, double-blinded study was designed to compare the effects of desflurane, isoflurane and sevoflurane when combined with remifentanil for induced hypotension on surgical conditions and operative field during tympanoplasty.

METHODS

Sixty patients undergoing tympanoplasty were enrolled in the study. The patients were randomized into three groups of 20 each to receive the inhalation anaesthetics desflurane, isoflurane or sevoflurane. Propofol 2 mg kg(-1) was administered for induction of anaesthesia in all groups. All patients received a continuous infusion of remifentanil which was titrated between 0.2 and 0.5 microg kg(-1) min(-1) to achieve a mean blood pressure (BP) of 60-70 mmHg. Nitroglycerine was infused if this BP could not be achieved. Arterial pressures were recorded continuously throughout the operation. Surgical conditions were assessed every 20 min by the blinded surgeon using a six-point category scale (0-5).

RESULTS

One patient in the desflurane group and two patients in isoflurane group required nitroglycerine to maintain desired mean BP. Sustained controlled hypotension was sufficient in all of the groups throughout surgery. Category scale scores were < or =3 throughout the study, except one patient in the sevoflurane group who had a score of 4 at the 60th minute of the operation. No difference was found among groups when haemodynamic parameters and surgical category scale scores were compared. There were no postoperative respiratory and circulatory complications.

CONCLUSION

Desflurane, sevoflurane or isoflurane combined with remifentanil provided adequate induced hypotension and similar operating conditions and any of them could be safely and equally used in anaesthesia for tympanoplasty.

Effect of low-dose N-acetyl-cysteine infusion on tourniquet-induced ischaemia-reperfusion injury in arthroscopic knee surgery

BACKGROUND

Temporary occlusion of blood flow is used during arthroscopic knee surgery in order to provide a bloodless surgical field. The resulting ischaemia-reperfusion causes lipid peroxidation, which contributes to tissue injury. The aim of the study was to investigate the effect of low-dose n-acetyl cysteine (NAC) infusion on oxidative stress by determining malondialdehyde (MDA) levels during arthroscopic knee surgery.

METHODS

Thirty patients, ASA I - II, undergoing arthroscopic knee debridement under a tourniquet were divided into NAC and control groups. Anaesthesia was induced with propofol, fentanyl and vecuronium bromide and maintained with desflurane in an equal parts O(2)-N(2)O mixture. In the NAC group, an infusion of NAC, 5 mg kg(-1).h(-1), was started after intubation, and continued until extubation. An equal volume of saline was infused to the control group. Duration of ischaemia, anaesthesia time, total dose of NAC infused were also recorded. Venous blood and synovial membrane tissue samples were obtained 10 min after the onset of NAC infusion but before tourniquet inflation (t1), after 30 min of ischaemia (t2), and after 5 min of reperfusion following tourniquet release (t3).

RESULTS

Plasma MDA levels were significantly lower in the NAC group on reperfusion. There were no differences between the groups in tissue MDA levels at ischaemia and reperfusion times.

CONCLUSION

Low-dose n-acetyl cysteine infusion attenuates lipid peroxidation and ischaemia-reperfusion injury in arthroscopic knee surgery requiring tourniquet application.

Upper cervical vertebrae movement during intubating laryngeal mask, fibreoptic and direct laryngoscopy: a video-fluoroscopic study

BACKGROUND AND OBJECTIVE

Minimizing cervical vertebrae motion during endotracheal intubation is important in patients with cervical instability. The aim of this study was to compare upper cervical spine extension during endotracheal intubation using three different techniques.

METHODS

Duration of intubation and movement of upper cervical vertebrae during endotracheal intubation were compared in 33 patients undergoing lumbar laminectomy. Patients requiring tracheal intubation under general anaesthesia and neuromuscular blockade were randomly allocated into three groups - direct laryngoscopy, intubating laryngeal mask (LM) airway and fibreoptic laryngoscopy. The procedure was recorded by video-fluoroscopy and analysed with computer-assisted measurements. The maximum movement of the C1/C2 and C2/C3 vertebrae during intubation were obtained. Data were analysed using one-way analysis of variance with Bonferroni and Kruskal-Wallis tests.

RESULTS

We found statistically significant movement between the first and second, but not between the second and third cervical vertebrae. The mean (+/-SD) movement at C1/C2 was 10.2 +/- 7.3 degrees with direct laryngoscopy, 5.0 +/- 6.3 degrees with LM and 1.6 +/- 3.2 degrees with fibreoptic laryngoscopy. This difference was statistically significant (P = 0.01) between the direct and fibreoptic laryngoscopy groups. The maximum movement at C2/C3 was 2.2 +/- 10.1 degrees with direct laryngoscopy, 3.5 +/- 5.1 degrees with LM and 0.5 +/- 3.2 degrees with fibreoptic laryngoscopy. Duration of intubation was significantly longer in the intubating LM group (P < 0.001).

CONCLUSION

We conclude that fibreoptic laryngoscopy is the more suitable intubation technique when cervical spine movement is not desired.

Tramadol encapsulated into polyhydroxybutyrate microspheres: in vitro release and epidural analgesic effect in rats

BACKGROUND

Controlled release techniques are used to increase the duration of action and decrease the toxicity of drugs. Any controlled release form of tramadol in spinal or epidural blocks has not been studied previously. Tramadol was encapsulated into polyhydroxybutyrate (PHB) microspheres and release kinetics was studied. The epidural analgesic effect of this solution in rats was also compared with free tramadol.

METHODS

Controlled release of tramadol from PHB microspheres into 10 ml of phosphate buffer solution at pH 7.4 and 37 degrees C was studied in vitro. In vivo studies were performed in 40 rats. Epidural catheters were placed during general anaesthesia. Rats were randomly allocated into one of the four study groups to receive normal saline, 4 mg of tramadol, PHB microspheres without tramadol, or 4 mg of tramadol encapsulated into PHB microspheres. Analgesia was evaluated with tail flick tests performed at 52.5 +/- 0.5 degrees C before injection and at intervals up to 30 h after injection. Catalepsy and loss of corneal reflexes were considered as signs of supraspinal toxicity.

RESULTS

In vitro drug release was observed for more than 6 days. Epidural analgesic effects of tramadol released from PHB microspheres were observed for 21 h, whereas an equal dose of free tramadol was effective for less than 5 h. No signs of toxicity were observed.

CONCLUSION

Controlled release of tramadol from PHB microspheres is possible, and pain relief during epidural analgesia is prolonged by this drug formulation compared with free tramadol.

Anesthesia for operative endoscopy

Developments in both instruments and techniques have led to an increasing popularity of endoscopic surgery during the last two decades. Even though there are numerous advantages to using endoscopic surgery, life threatening surgical and anesthetic complications still exist. Precautions must be taken to cope with the potential complications. Anesthetic technique must provide optimal surgical conditions and lead to early recovery of the patient. Monitorization must allow safety of the patient during these potentially hazardous procedures. Both the anesthesiologist and the surgeon must be thoroughly aware of the potential complications of the procedure. This review discusses the physiological alterations occurring during operative endoscopy, the principles of anesthetic management and complications related both to surgery and to anesthesia techniques.

Day-case laparoscopy: a comparison of prophylactic opioid, NSAID or local anesthesia for postoperative analgesia

BACKGROUND

The study was aimed to evaluate the analgesic efficacy, postoperative comfort, recovery characteristics and side effects of three different analgesic agents administered prophylactically.

METHODS

Eighty patients undergoing day-case minor operative laparoscopy were randomly allocated into four groups to receive tenoxicam 20 mg i.v. (Group T), fentanyl 100 microg i.v. (Group F), 5 ml of bupivacaine 2.5 mg/ml for infiltration of trocar sites (Group B), 30, 10 and 5 min before incision respectively. Bupivacaine, 35 ml, 2.5 mg/ml was also administered into the pelvic cavity in Group B. Group P received only placebo. Postoperative pain, analgesic requirements, first response to verbal stimulus, first analgesic requirement, ability to walk without help, to drink and to void, blood pressures, SpO2 and respiration rates were recorded in the PACU. Postoperative pain was evaluated by verbal rating scale. Pain scores, analgesic requirements and side effects were evaluated by telephone calls until the 48th postoperative hour.

RESULTS

Postoperative pain scores were lower and time to requirement of rescue analgesics was longer in groups F and B compared to Group P. In the PACU, analgesic requirements were lower in Group B, compared to Group P. Nausea and vomiting were increased in Group F.

CONCLUSION

Tenoxicam 20 mg i.v. was found to be ineffective whereas bupivacaine was superior to other groups in reducing pain and analgesic requirements. Bupivacaine also increased time to first analgesics and obtained better recovery characteristics, underlining its value in prophylactic pain management compared to the other two agents.

Histological evaluation of repair using a bioresorbable membrane beneath a resin-modified glass ionomer after mechanical furcation perforation in dogs' teeth

Resorbable barriers have been shown both clinically and histologically to produce favorable periodontal regenerative outcomes. The purpose of the present study was to evaluate the histological response to one such resorbable barrier (Atrisorb) when used as a matrix under a resin-modified glass ionomer (RMGI) sealant in the repair of furcation perforations in experimental animals. After anesthesia, pulp extirpation and filling of radicular canals with zinc oxide-eugenol cement, furcal perforations were made in 30 lower premolar (P2, P3, and P4) teeth of labrador dogs with a 1 mm diameter round bur in a conventional handpiece. The perforated teeth were randomly divided into two groups of 15 teeth. Group 1 teeth were treated with RMGI alone and group 2 with the resorbable barrier under RMGI. Six teeth without perforations served as negative controls. Pulp chambers of all teeth were filled with RMGI cement. Animals were sacrificed after 3 months. The teeth and the surrounding structures were processed for light microscopy. There were no differences found between results for glass ionomer alone and barrier with glass ionomer. The conclusion of this study is that placement of a resorbable barrier at the pulp chamber aspect of a furcation perforation did not result in superior healing, compared with the use of resin-modified glass ionomer alone.