Intraoperative Hypotension Increased Risk in the Oncological Patient

Carcinoid crisis: The challenge is still there

Carcinoid crisis (CC) has classically been considered the extreme end of the spectrum of carcinoid syndrome (CS). However, this presumption and other aspects of CC remain poorly understood. Consequently, current clinical guidelines are based on a low quality of evidence. There is no standard definition of CC and its incidence is unknown. Patients with florid CS and elevated serotonin (or its derivatives) which develop CC have been reported during decades. Nevertheless, the hypothesis that CC is due to the sudden massive release of serotonin or other vasoactive substances is unproven. Many triggers of CC (surgery, anaesthesia, peptide receptor radionuclide therapy, tumour biopsy or liver-directed treatments) have been proposed. However, data from studies are heterogeneous and even contradictory. Finally, the role of octreotide in the prevention of CC has been questioned. Herein, we report a clinical case and perform a critical review of the evidence available today on this topic.

Dexmedetomidine versus remifentanil in nasal surgery: a systematic review and meta-analysis

BACKGROUND

Nasal surgeries, addressing anatomical variations for form and function, require careful anesthesia administration, including dexmedetomidine and remifentanil. This meta-analysis evaluates their safety and efficacy variations in nasal surgeries, emphasizing patient comfort and optimal outcomes.

METHODS

Four electronic databases (PubMed, Scopus, Web of Science, and CINAHL Complete) were searched for records in English. Studies that measure the effect of dexmedetomidine versus remifentanil on patients underwent nasal surgery were included. The Cochrane Collaboration's tool was used to assess the quality of the included studies. A random-effect model was preferred and statistical analysis was performed by Stata software version 17.

RESULTS

Out of an initial pool of 63 articles, five studies were selected for this analysis. All of these chosen studies were Randomized Controlled Trials (RCTs). The meta-analysis involved a total of 302 participants, with 152 in the remifentanil group and 150 in the dexmedetomidine group. The analysis aimed to compare the effects of Dexmedetomidine and Remifentanil on heart rate (HR) and mean arterial pressure (MAP) during surgery. Both groups exhibited similar MAP and HR, with the exception of a slightly lower HR in the remifentanil group at the 15th minute of surgery (Standardized Mean Difference: -0.24 [-0.83, 0.34]). Furthermore, when evaluating the impact of these medications on post-surgery outcomes, including pain levels, the use of pain relief medications, patient-surgeon satisfaction, agitation scores, and recovery time, no significant differences were observed between the two medications in any of these aspects.

CONCLUSION

In summary, the study compared Dexmedetomidine and Remifentanil in nasal surgeries anesthesia. No significant differences were found in heart rate, blood pressure, satisfaction, pain, agitation, or recovery time. The study had limitations, and future research should establish standardized protocols and consider various surgical factors.

Comparison of Bioimpedance Versus Pulse Contour Analysis for Intraoperative Cardiac Index Monitoring in Patients Undergoing Kidney Transplantation

Background

Cardiac index (CI; cardiac output indexed to body surface area) is routinely measured during kidney transplant surgery. Bioimpedance cardiometry is a transthoracic impedance as the non-invasive alternative for hemodynamic monitoring, using semi-invasive uncalibrated pulse wave or contour (UPC) analysis.

Objectives

We performed a cross-sectional observational study on 50 kidney transplant patients to compare the CI measurement agreement, concordance rate, and trending ability between bioimpedance and UPC analysis.

Methods

For each patient, CI was measured by bioimpedance analysis (ICON^TM) and UPC analysis (EV1000^TM) devices at three time points: after induction, during incision, and at reperfusion. The device measurement accuracy was assessed by the bias value, limit of agreement (LoA), and percentage error (PE) using Bland-Altman analyses. Trending ability was assessed by angular bias and polar concordance through four-quadrant and polar plot analyses.

Results

From each time point and pooled measurement, the correlation coefficients were 0.267, 0.327, 0.321, and 0.348. Bland-Altman analyses showed mean bias values of 1.18, 1.06, 1.48, and 1.30, LoA of -1.35 to 3.72, -1.39 to 3.51, -1.07 to 4.04, and -1.17 to 3.78, and PE of 82.21, 78.50, 68.74, and 74.58%, respectively. Polar plot analyses revealed angular bias values of -10.37º, -15.01º, -18.68º, and -12.62º, with radial LoA of 89.79º, 85.86º, 83.38º, and 87.82º, respectively. The four-quadrant plot concordance rates were 70.77, 67.35, 65.90, and 69.79%. These analyses showed poor agreement, weak concordance, and low trending ability of bioimpedance cardiometry to UPC analysis.

Conclusions

Bioimpedance and UPC analysis for CI measurements were not interchangeable in patients undergoing kidney transplant surgery. Cardiac index monitoring using bioimpedance cardiometry during kidney transplantation should be interpreted cautiously because it showed poor reliability due to low accuracy, precision, and trending ability for CI measurement.

Effect of Different Loading Doses of Dexmedetomidine on Controlled Hypotension and the Incidence of Bradycardia During Rhinoplasty: A Clinical Trial

Controlled hypotension, with a mean arterial pressure (MAP) of 60 mmHg - 70 mmHg, provides a bloodless and visible surgical field during rhinoplasty. It has been shown that dexmedetomidine, an α2-adrenoreceptor agonist, is a suitable choice in this regard. One of the disadvantages of this drug is the possibility of severe bradycardia during infusion. Therefore, we compared lower intravenous (IV) loading doses to determine whether the hypotensive effect of the drug was preserved and the bradycardia incidence decreased. In this randomized, double-blinded clinical trial, 81 patients aged 18 to 50 years with the American Society of Anesthesiologists physical status (ASA-PS) class I and II, scheduled for rhinoplasty randomly received 1.0, 0.9, and 0.8 µg/kg (named as groups 1.0, 0.9, and 0.8, respectively) of IV dexmedetomidine before the induction of anesthesia followed by infusion (0.3 - 0.7 µg/kg/h) during operation. The patients' heart rate (HR), MAP, the requirements for nitroglycerin (NTG) and extra fentanyl, as well as the incidence of bradycardia, were recorded. Bleeding and visibility of the surgical field were scored by the surgeon using a 6-point visual scale. MAPs, HRs, and consumption of NTG and extra fentanyl were similar in the studied groups. The surgical field was more visible and bloodless in group 1.0 compared to group 0.8 (P < 0.001); the differences were not significant between groups 1.0 and 0.9 (P = 0.605). The incidence (P = 0.027) and the severity of bradycardia (P = 0.017) were higher in the groups with higher loading doses. We concluded that dexmedetomidine is an acceptable agent to provide controlled hypotension. A loading dose of 0.9 µg/kg, but not 0.8 µg/kg, provides similar surgical field conditions as the dose of 1 µg/kg. Furthermore, despite the decrease in the incidence of bradycardia, the hypotensive effect of the drug is preserved.