Risks of Polymyxin B Nephrotoxicity and Its Precursors in the Intensive Care Unit: A Retrospective Cohort Study.

BACKGROUND AND AIM: Polymyxin group antibiotics constitute a part of our limited arsenal in the treatment of multidrug-resistant gram-negative bacteria. However, their use is limited especially due to nephrotoxicity and other side effects. In this study, we primarily aimed to determine the effect of polymyxin B on the rate of nephrotoxicity in critically ill patients, and secondly to identify the factors that facilitate nephrotoxicity caused by polymyxin B. MATERIALS AND METHODS: The study was designed as a retrospective cohort study and conducted by scanning patients aged 18 years or older who had been admitted to our intensive care unit (ICU) in 2022 and treated with polymyxin B for at least 72 hours. Patients without chronic renal failure and acute kidney injury (AKI) before starting polymyxin B therapy were included and AKI was examined after the use of polymyxin B. The patients were then divided into two groups, those with AKI and those without AKI. We tried to find factors that may facilitate AKI by comparing the two groups. RESULTS: Of the patients, 26 were female and 34 were male. In 21 of the patients (35%), renal damage of varying degrees developed; these patients belonged to the nephrotoxicity (NT) group, while the rest belonged to the non-nephrotoxicity (non-NT) group. We found that advanced age (p=0.008), low baseline GFR (p=0.01), baseline creatinine (p=0.006), BMI (p=0.011), concomitant diseases (p<0.001), and days of use of polymyxin B (p=0.006) were statistically different between the two groups. In multivariate analysis of univariate analysis, we found that duration of polymyxin B use, BMI, and advanced age were independent risk factors for AKI development. CONCLUSION: We found that 21 (35%) of 60 intensive care unit patients who had no previous history of kidney injury developed kidney injury after being treated with polymyxin B. We identified advanced age, high BMI, and duration of polymyxin B use as independent risk factors. Therefore, we recommend close monitoring of renal function and prompt intervention, particularly in patients with risk factors, during polymyxin B use.

Assessment of the Tip Position of Central Venous Catheters Inserted Using Peres' Height Formula.

OBJECTIVES: The tip of a central venous catheter (CVC) should be positioned in the proximity of the cavo-atrial junction (CAJ) where the lower third of the superior vena cava (SVC) and the upper right atrium (RA) are located to prevent life-threatening complications. This study aimed to determine the accuracy of Peres' height formula in predicting the correct insertion depth of CVC.  Methods: A total of 332 patients were enrolled in this prospective observational study. All CVCs were inserted using Peres' formula. The 'correct' tip position of CVC was the placement of the CVC tip 1 cm above and 1 cm below the carina in CXR. Rates of correct placements for each side and site of catheter insertions, gender, and body mass index (BMI) differences were evaluated. RESULTS: The correct placement rate of all catheters was 74.4%. There were statistically significant correlations between the correct placement of right-sided jugular and subclavian catheters (p<0.001) and left-sided jugular and subclavian catheters (p=0.014). There was a statistically significant difference in male patients (p=0.047). Higher BMI resulted in a lower rate of correct placement with no statistically significant difference (p=0.457). CONCLUSIONS: Peres' formula can be easily used to determine the correct position of CVC tips with a success rate in the Turkish population. However, practitioners should be aware of the low accuracy rate of Peres' formula in female patients (68.5%) and patients with BMI over 35 kg/m2 (62.5%).

Effect of preoperative hospitalisation period on postoperative cognitive dysfunction in patients undergoing hip surgery under regional anaesthesia.

AIM OF THE STUDY: The main objective of this prospective and observational study was to investigate the effect of the preoperative hospitalisation period on early postoperative cognitive dysfunction (POCD) development in patients undergoing total hip replacement surgery under regional anaesthesia. MATERIALS AND METHODS: Between November 2013 and September 2014, 64 patients were enrolled in the study. Mini Mental Test (MMT) scores were obtained on the initial admission day (MMT1), 24 hours prior to the surgery (MMT2) and 24 hours after the surgery (MMT3). The patients were divided into two groups according to the MMT scores: 'no cognitive dysfunction' (group 1) and 'cognitive dysfunction' (group 2). Differences between the groups were evaluated statistically. The statistical significance level was set as P < .05 in a 95% confidence interval. RESULTS: The POCD incidence rate was calculated as 43.8% in all patients. The preoperative hospitalisation duration was significantly longer in patients with POCD than in patients without POCD (P < .001). The factors that affected POCD development were found to be advanced age (P < .001), high American Society of Anesthesiologists scores (P = .004), the presence of comorbid disease (P = .025), durations of surgery (P = .018) and decreased postoperative haematocrit levels (P = .014). CONCLUSION: In this study, we observed that patients with early POCD had relatively longer preoperative hospitalisation periods than those in patients without POCD. We consider that prolonged preoperative hospitalisation may contribute to increased POCD incidence rates in patients with risk factors.

Acute Back Pain Following Surgery under Spinal Anesthesia.

INTRODUCTION: The purpose of this study was to determine the factors having a role in the occurrence of acute back pain following spinal anesthesia. METHODS: Six hundred and forty-nine patients who underwent surgery under spinal anesthesia were enrolled in this prospective observational study. Patients' age, sex, BMI, ASA physical status, educational status, history of back pain, spinal needle radius, spinal interspace level of intervention, method of approach for spinal anesthesia, position during spinal anesthesia, angle of puncture with respect to the spinal ligaments, magnitude of pain during intervention, number of lumbar punctures, number of bony contacts, amount of bupivacaine administered intrathecally, type of surgical procedure, surgical position, duration of the surgery, and duration of anesthesia parameters were recorded. Patients were inquired for existence and magnitude of back pain on the 1st day and the 4th week postoperatively. Multivariate analysis is performed via logistic regression model to parameters that are found to be significant in univariate analysis. RESULTS: Assessment of the data from the postoperative 1st day showed 29.3% of the patients suffered back pain. Postspinal acute back pain was related to the number of bony contacts (P = 0.016), history of back pain (P = 0.0001), spinal needle radius (P = 0.022), and duration of the surgery (P = 0.037). CONCLUSION: Contrary to the common belief, it is demonstrated in this study that number of lumbar punctures, method of approach and position of the spinal anesthesia, age, sex, surgical position, and the type of the surgery did not correlate with occurrence of acute back pain following spinal anesthesia.

Remifentanil versus remifentanil with paracervical block on plasma remifentanil concentrations and pulmonary function tests for transvaginal ultrasound-guided oocyte retrieval.

STUDY OBJECTIVE: The aim of this study is to compare plasma remifentanil concentrations and pulmonary function tests in subjects receiving remifentanil infusion (RI) versus RI with paracervical block (PCB) during transvaginal ultrasound-guided oocyte retrieval (TUGOR). DESIGN: Prospective, randomized. SETTING: Assisted Conception Unit. PATIENTS: Forty American Society ofAnesthesiologists I subjects requiring TUGOR. INTERVENTION: After ovarian hyperstimulation, subjects were randomly allocated into two groups to receive either RI (Group RI, n = 20) or RI with PCB (Group RI + PCB, n = 20). MEASUREMENTS: Heart rate (HR), mean arterial pressure (MAP), peripheral oxygen saturation (SpO2), end tidal carbon dioxide (ETCO2) tension, forced expiratory volume in 1 second (FEV1) and forced vital capacity (FVC), and amount of remifentanil used were collected. Plasma remifentanil concentrations were calculated with STANPUMP software. MAIN RESULTS: HR, MAP, ETCO2, SpO2, FEV1, and FVC did not differ between the groups. Total amount of remifentanil used were 486 +/- 1.81 microg and 321 +/- 0.87 microg in groups RI and RI + PCB, respectively, (p < 0.05). In Group RI, plasma remifentanil concentrations were 4.7 ng mL(-1) and 4.2 ng mL(-1) during the second transvaginal puncture, and at the end of TUGOR, respectively, whereas corresponding plasma remifentanil concentrations were 3.1 ng mL(-1) and 2.6 ng mL(-1) in Group RI + PCB (p < 0.05). CONCLUSION: Both anesthesia regimens provided satisfactory analgesia without affecting FEV1 and FVC, but significantly higher plasma remifentanil concentrations were calculated when only RI was used as an anesthetic technique.