Transient increases in intraoperative parathyroid levels related to anesthetic technique

Comparison of the Effect of Anesthetic Agents on Blood Levels of Parathyroid Hormone and Ionized Calcium: A Prospective Randomized Controlled Trial

The aim of this randomized control trial is to compare the effect of anesthetic agents on blood levels of parathyroid hormone and ionized calcium. 77 American Society of Anesthesiologists I-II patients who would undergo laparoscopic cholecystectomy were enrolled into this prospective study and randomized into 3 groups with sealed envelope technique as Group S: sevoflurane, Group D: desflurane, and Group TIVA: total intravenous anesthesia. The first blood sample was used to check the baseline blood levels of parathyroid hormone and ionized calcium. In Group S or D, maintenance of anesthesia was being performed with 1 MAC (minimum alveolar concentration) sevoflurane or desflurane, respectively, while in Group TIVA, it was performed with 150 mcg/kg/min propofol and 1 mcg/kg/min remifentanil IV infusions. At the 30^th minute of anesthesia and at the 1^st hour of end of anesthesia, 2^nd and 3^rd blood samples, respectively, were used to check the blood levels of PTH and Ca. During perioperative period, hemodynamic parameters were also noted. Blood levels of parathyroid hormone at the 30^th min after anesthesia were found to be significantly different between groups (P=0,01). The PTH level at the 30^th min after anesthesia was found significantly higher in Group S than that of Groups D and TIVA (P=0.005 and P=0.001, respectively). Blood levels of ionized calcium at 30^th min after anesthesia were found significantly different between groups (P=0,048). It was found significantly higher in Group TIVA than that in Group S (P=0.024). Desflurane seems to be the best agent for parathyroidectomy procedures. Future research studies are needed to be conducted to reach out more correct and valuable outcomes.

Relationship of Vitamin D Deficiency and Intraoperative Parathyroid Hormone Elevation in Completion and Total Thyroidectomy

Objective

To quantify how frequently intraoperative parathyroid hormone levels increase during thyroid surgery and to explore a possible relationship between secondary hyperparathyroidism due to vitamin D deficiency and elevation in intraoperative parathyroid hormone.

Study Design

Case series with chart review.

Setting

Tertiary academic center.

Subjects and Methods

A total of 428 consecutive patients undergoing completion and total thyroidectomy by the senior author over a 7-year period were included for analysis. All patients had baseline and postexcision intraoperative parathyroid hormone levels as well as vitamin D levels from the same laboratory. Institute of Medicine criteria were employed for vitamin D stratification (>30, normal; 20-29.9, insufficient; <20, deficient) . Other data analyzed include sex, age, neck dissection status, and parathyroid autotransplantation.

Results

A total of 118 patients (27.6%) had an intraoperative parathyroid hormone elevation above baseline. Patients with vitamin D deficiency were significantly more likely to experience hormone elevation ( P = .04). When parathyroid hormone rose, it did so by a mean 32.1 pg/mL. Patients with vitamin D deficiency demonstrated significantly larger hormone increases ( P = .03).

Conclusion

Elevation in intraoperative parathyroid hormone levels above baseline after completion and total thyroidectomy occurs in over one-fourth of cases and is significantly associated with vitamin D deficiency. This study is the first to report this observation. We hypothesize that vitamin D deficiency in these patients may create a subclinical secondary hyperparathyroidism that leads to intraoperative parathyroid hormone elevation when the glands are manipulated. Additional studies will be needed to explore this physiologic mechanism and its clinical significance.

Clinical Utility of Intraoperative Parathyroid Hormone Measurement in Children and Adolescents Undergoing Total Thyroidectomy

Background: Hypoparathyroidism is one of the most common complications for patients undergoing total thyroidectomy. Our study's primary objective was to assess if intraoperative PTH levels correlate with parathyroid gland function recovery time in pediatric patients following total thyroidectomy. Methods: Retrospective review of pediatric patients who underwent thyroid surgery at CHOP for demographics and laboratory test values (calcium, phosphorus, and parathyroid hormone). We defined Time of Recovery (TOR) as the time difference from first intra-operative parathyroid hormone level (ioPTH) timepoint until normalization of PTH (> 10 pg/mL) post-thyroidectomy. Calcium and vitamin D supplements were weaned following normalization of calcium and phosphorous levels postoperatively. Patients were excluded if they lacked three intraoperative PTH timepoints or were missing postoperative follow-up PTH data. Results: 65 patients (54 female), median age 15 (range 5-23 years), underwent thyroid surgery and met study inclusion criteria. The correlations of 2nd and 3rd ioPTHs with TOR were statistically significant (p < 0.05): the lower the ioPTH, the greater the recovery time. Stratifying patients into high-risk (2nd ioPTH ≤ 10 pg/mL), moderate-risk (2nd ioPTH between 10 and 20 pg/mL), and low-risk (2nd ioPTH ≥ 20 pg/mL) tertiles, the TOR decreased by orders of magnitudes from an average of 43.13 ± 76.00 to 6.10 ± 17.44 to 1.85 ± 6.20 days. These differences were statistically significant (p < 0.05). Conclusions: Our study results confirm the usefulness of intraoperative PTH levels to predict pediatric patient recovery post-surgery and provides useful anticipatory guidance to optimize timing and frequency of postoperative laboratory surveillance.

Intraoperative parathormone spikes during parathyroidectomy may be associated with multiglandular disease

BACKGROUND

The importance of intraoperative parathormone "spikes" during parathyroidectomy remains unclear. This study compared patients with and without intraoperative parathormone spikes during parathyroidectomy using the criterion of a > 50% parathormone and determined the effect of intraoperative parathormone spikes on operative outcome.

METHODS

We performed a retrospective review of prospectively collected data on 683 patients who underwent parathyroidectomy guided by intraoperative parathormone monitoring. An intraoperative parathormone "spike value" was calculated by subtracting the preincision intraoperative parathormone value from the pre-excision intraoperative parathormone value (SV = PE - PI). An intraoperative parathormone spike was defined as having a positive spike value ≥9 pg/mL (≥10th percentile of all spike values).

RESULTS

Of 683 patients, 224 (33%) had intraoperative parathormone spikes and a greater rate of multiglandular disease (8% vs. 3%, P < 0.05) and bilateral neck exploration (10% vs. 5%, P < 0.05) compared with patients without intraoperative parathormone spikes. Overall, there were no differences between parathyroidectomy patients with and without intraoperative parathormone spikes in terms of operative success (98.2% vs. 98.0%), failure (1.8% vs. 2.0%), or recurrence rates (0.4% vs. 1.3%).

CONCLUSIONS

Although the presence of intraoperative parathormone spikes may increase suspicion for multiglandular disease, the ability of intraoperative parathormone monitoring to predict operative success after parathyroidectomy is not affected by spikes.

Effect of general anesthesia and intubation on parathyroid levels in normal patients and those with hyperparathyroidism

BACKGROUND

Induction of general anesthesia and endotracheal intubation may precipitate parathyroid hormone (PTH) elevation in patients with primary hyperparathyroidism (HPT). The purposes of this study were to revisit this observation and to study its impact in healthy patients.

METHODS

Patients with primary HPT who underwent parathyroidectomy were retrospectively studied. The PTH was sampled and compared: before, immediately after general anesthesia and endotracheal intubation, and 15 minutes after parathyroidectomy. Healthy adults who underwent elective operations were prospectively studied. The PTH was sampled before general anesthesia and endotracheal intubation, immediately after, and 15 minutes later.

RESULTS

Thirty-one patients, aged 28-89 years (mean 60.1 ± 13 years), were retrospectively studied. The PTH was significantly elevated after general anesthesia and endotracheal intubation (P = .014). Fifty patients, aged 21-86 years (mean 54 ± 15 years), were prospectively studied. The PTH elevation after general anesthesia and endotracheal intubation was not significant.

CONCLUSION

General anesthesia and endotracheal intubation causes an immediate, steep, and significant PTH elevation in patients with primary HPT but only a minor change in healthy adults. The difference may be attributed to an impaired adrenergic response in patients with primary HPT.

Endocrinopathies: The current and changing perspectives in anesthesia practice

The gateways to advancements in medical fields have always been accessed through the coalition between various specialties. It is almost impossible for any specialty to make rapid strides of its own. However, the understanding of deeper perspectives of each specialty or super specialty is essential to take initiatives for the progress of the other specialty. Endocrinology and anesthesiology are two such examples which have made rapid progress in the last three decades. Somehow the interaction and relationship among these medical streams have been only scarcely studied. Diabetes and thyroid pathophysiologies have been the most researched endocrine disorders so far in anesthesia practice but even their management strategies have undergone significant metamorphosis over the last three decades. As such, anesthesia practice has been influenced vastly by these advancements in endocrinology. However, a comprehensive understanding of the relationship between these two partially related specialties is considered to be an essential cornerstone for further progress in anesthesia and surgical sciences. The current review is an attempt to imbibe the current and the changing perspectives so as to make the understanding of the relationship between these two medical streams a little simple and clearer.

The final intraoperative parathyroid hormone level: how low should it go?

BACKGROUND

In minimally invasive surgery for primary hyperparathyroidism (HPT), intraoperative parathyroid hormone (IOPTH) monitoring assists in obtaining demonstrably better outcomes, but optimal criteria are controversial.

METHODS

The outcomes of 1,108 initial parathyroid operations for sporadic HPT using IOPTH monitoring from 1997 to 2011 were stratified by final post-resection IOPTH level. All patients had adequate follow-up to verify cure.

RESULTS

With mean follow-up of 1.8 years (range 0.5-14.3 years), parathyroidectomy using IOPTH monitoring failed in 1.2 % of cases, with an additional 0.5 % incidence of long-term recurrence at a mean of 3.2 years (range 0.8-6.8 years) postoperatively. Operative success was equally likely with a final IOPTH drop to 41-65 pg/mL vs ≤40 pg/mL (p = 1). In the 76 patients with an elevated baseline IOPTH level that did not drop to ≤65 pg/mL, surgical failure was 43 times more likely than with a drop into normal range (13 vs. 0.3 %; p < 0.001). When the final IOPTH level dropped by >50 % but not into the normal range, surgical failure was 19 times more likely (3.8 vs. 0.2 %; p = 0.015). Long-term recurrence was more likely in patients with a final IOPTH level of 41-65 pg/mL than with a level ≤40 pg/mL (1.2 vs. 0; p = 0.016).

CONCLUSIONS

Adjunctive intraoperative PTH monitoring facilitates a high cure rate for initial surgery of sporadic primary hyperparathyroidism. A final IOPTH level that is within the normal range and drops by >50 % from baseline is a strong predictor of operative success. Patients with a final IOPTH level between 41-65 pg/mL should be followed beyond 6 months for long-term recurrence.

Evaluation of intravenous administration of alfaxalone, propofol, and ketamine-diazepam for anesthesia in alpacas

OBJECTIVE

To evaluate the effects of induction of anesthesia with alfaxalone in alpacas.

STUDY DESIGN

Prospective, randomized, crossover design.

ANIMALS

Five healthy alpacas (96.7 ± 19.9 kg, 9.6 ± 3.1 years old).

METHODS

The alpacas were anesthetized on three occasions with alfaxalone, propofol, or ketamine-diazepam by intravenous injection. Quality of induction and intubation was assessed using a simple descriptive scale, and quality of recovery was scored: 1 (very poor)-5 (excellent). The auricular artery was catheterized for measurement of systolic (SAP), mean (MAP), and diastolic (DAP) arterial pressures and collection of blood. Variables measured were hemoglobin oxygen saturation (SpO2 ), respiratory rate, and end-tidal carbon dioxide partial pressure (Pe'CO2 ), and ECG. Repeated measures anova was used to assess effects of drug and time. Significance was set at p < 0.05.

RESULTS

Mean dose of alfaxalone sufficient to allow intubation was 2.1 mg kg(-1) . Induction was excellent with all protocols. Heart rate (HR), SAP and MAP were significantly higher following alfaxalone compared to ketamine-diazepam. Blood lactate concentration when standing following alfaxalone was higher compared to minutes 1 and 6, and to propofol (p < 0.05). All alpacas required oxygen supplementation and mechanical ventilation to treat SpO2  < 90% or Pe'CO2  > 60 mmHg. Time from induction to standing was longer with alfaxalone (34.1 ± 3.2 minutes) than propofol (19.0 ±4.3 minutes) or ketamine-diazepam (24.9 ±1.7 minutes). Recovery quality median scores were clinically and statistically different: 2 (alfaxalone), 4 (ketamine-diazepam), and 5 (propofol). Tremors, paddling, rolling, seizure-like activity and thrashing characterized recovery from alfaxalone.

CONCLUSION

Recovery quality was worst with alfaxalone. HR, SAP, MAP were increased at minute 1 in all protocols. Transient hypercapnia and hypoxia was observed with all protocols.

CLINICAL RELEVANCE

All protocols were adequate for induction of anesthesia. Alfaxalone alone in unpremedicated alpacas is not recommended.

Anesthetic techniques and parathyroid hormone levels: Predictor of surgical decisions

Endocrine surgeries have always been challenging and throw numerous challenges to the surgeons, anesthesiologists, and the endocrinologists. A thorough knowledge of the pathophysiological aspects associated with endocrinopathies is mandatory for the attending anesthesiologist. Parathyroid surgery is a very delicate procedure that requires immense and meticulous preparation during the perioperative period for achieving a clinical outcome. Parathyroid hormone (PTH) levels during intra-operative period can influence the decision making in surgery. Anesthetic techniques also play a significant role in the secretion of PTH during perioperative period, which can be decisive in re-assessment of surgical procedure on operation table. The present communication briefly outlines the various anesthetic techniques, which influence the secretion of PTH and also influence surgical decision making.

Evaluation of the 'putative' role of intraoperative intact parathyroid hormone assay during parathyroidectomy for secondary hyperparathyroidism. A retrospective study on 35 consecutive patients: intraoperative iPTH assay during parathyroidectomy

In the surgical treatment of secondary hyperparathyroidism (2HPT) of chronic kidney disease (CKD), a parathyroidectomy (PTx) of 4 glands can only be presumed as 'total', and indications for autoimplantation are complex. Intraoperative rapid parathyroid hormone assay could be useful to predict a radical resection. We evaluated iPTH levels 20 min and 24 h after a 4-gland PTx in 35 patients to determine the predictive value of intraoperative iPTH assay. We analysed retrospectively 35 patients affected by 2HPT of CKD, 13 undergoing total parathyroidectomy (TP) and 22 TP + autoimplantation (TPai), after removing 4 glands in 33 cases and 5 glands in 2. Intact PTH assays were acquired after 40 min before induction of anaesthesia, after removing both ipselateral glands, at 20 min after surgery and on postoperative day 1. 20 min after 4-gland PTx, a decrease of iPTH levels >80 % of the preoperative value was observed in 27 of 35 cases (77.1 %) and <80 % in 8 of 35 cases (22.8 %). In 6 of these 8 patients, iPTH levels were within the normal range 24 h after surgery. Although the intraoperative iPTH assays are of interest in the treatment of 2HPT, the predictive value of this method is not entirely satisfactory. In fact, a 4-gland PTx ensures euparathyroidism in most cases, even when intraoperative iPTH assays are not trustworthy; however, intraoperative iPTH assay, although not a perfect 'tool', is a proved aid for the surgeon in making his decision.