Zeynep Kayhan | Baskent University (original) (raw)

Papers by Zeynep Kayhan

Translational perioperative and pain medicine, Mar 31, 2023

Journal of Clinical Anesthesia, Feb 1, 2017

Background: Video-laryngoscopes are new intubation devices, which improve an indirect view of the... more Background: Video-laryngoscopes are new intubation devices, which improve an indirect view of the upper airway. In dif ficult airway management, they improve Cormack-Lehane grade 1 and achieve the same or a higher intubation success rate in less time, compared with direct laryngoscopes 2. We

Turkish journal of anaesthesiology and reanimation, May 2, 2023

Objective: The aim of this study was to present our experience in liver transplantation recipient... more Objective: The aim of this study was to present our experience in liver transplantation recipients and renal transplantation recipients during caesarean section. Methods: Retrospective data regarding liver transplantation recipients and renal transplantation recipients who underwent caesarean section between January 1997 and January 2017 have been collected from the hospital records. Results: Fourteen live births occurred from 5 liver transplantation recipients and 9 renal transplantation recipients, all of them from caesarean section. The mean maternal age (28.4 ± 4.0 years vs. 29.2 ± 4.1 years, P = .38), body weight before conception (57.4 ± 8.8 kg vs. 64.5 ± 8.2 kg, P = .48), and the time from transplantation to conception (99.0 ± 50.7 months vs. 101.0 ± 57.5 months, P = .46) were similar for 5 liver transplantation recipients and 9 renal transplantation recipients, respectively. Four caesarean sections were performed under general anaesthesia, whereas spinal anaesthesia was used in 10 patients. The mean birth weight was similar (2502 ± 311g vs. 2161 ± 658 g, P = .3). There were 3 premature deliveries in liver transplantation recipients versus 6 premature deliveries in renal transplantation recipients and 2 low-birth-weight infants (<2500 g) in liver transplantation recipients versus 4 in renal transplantation recipients among 14 newborns. Infants small for gestational age were diagnosed in 9/14 (3 liver transplantation recipients versus 6 renal transplantation recipients, P = 1). Conclusion: General and regional anaesthesia can be safely used during caesarean delivery of liver transplantation recipients and renal transplantation recipients without increased risk of graft losses. Prematurity and low birth weight were mainly due to the cytotoxic drugs for immunosuppression. There are no differences in liver transplantation recipients and renal transplantation recipients for maternal and foetal complications according to our data.

Resuscitation, May 1, 2004

Resuscitation, Volume 61, Issue 2, Pages 245, May 2004, Authors:Akpek A. Elif; Kayhan Zeynep.

Transplant International, Jul 1, 2003

Liver transplantation involving living-related donors has been adopted in many centers as a way o... more Liver transplantation involving living-related donors has been adopted in many centers as a way of relieving organ shortage. This study reviewed the anesthetic considerations for donor operations at our institution in relation to intraoperative blood transfusion, complications, and postoperative liver function test results. From January 1990 to May 2001, 30 living-related liver transplantations were performed at Başkent University Hospital, Ankara. The donor data used for analysis were retrospectively obtained through chart review, anesthesia records, and the computerized hospital database. Left lobectomy was performed in 19 cases, and left lateral segmentectomy in 11 cases. Intraoperatively, the average volume of intravenous fluids used was 6431+/-468 ml, and the average amount of blood transfused was 2.1+/-0.4 units. The mean postoperative hospital stay was 11.5+/-1.3 days. The only intraoperative complication observed in these 30 donors was severe bleeding during retrohepatic vena cava dissection in one of the cases. The postoperative complications related to anesthesia were one case each of shoulder pain, neuropraxia, and compartment syndrome. The levels of total and direct bilirubin, aspartate aminotransferase, and alanine aminotransferase peaked within the first 2 postoperative days (2.19+/-0.36 mg/dl, 1.02+/-0.18 mg/dl, 245.7+/-26.6 U/l, 313.5+/-51.9 U/l, respectively). In all 30 donors, these levels had normalized by 1 month after surgery. Maximal efforts must be applied in the anesthetic approach to minimize donor complications in living-related liver transplantation; however, this will not completely eliminate some risks to the donor.

European Journal of Anaesthesiology, Jun 1, 2013

Acta clinica Croatica. Suplement, 2016

The primary aim of this single center retrospective study was to evaluate difficult mask ventilat... more The primary aim of this single center retrospective study was to evaluate difficult mask ventilation (DMV) and difficult laryngoscopy (DL) in a unique group of obese patients. A total of 427 adult patients with body mass index (BMI) ≥25 and surgically treated for endometrial cancer from 2011 to 2014 were assessed. Additional increase in BMI, comorbidities, bedside screening tests for risk factors, and the tools used to manage the patients were noted and their effects on DMV and/or DL investigated. Every escalation in the number of risk factors increased the probability of DMV 2.2-fold, DL 1.8-fold and DMV+DL 3.0-fold. Among bedside tests, limited neck movement (LNM), short neck (SN) and absence of teeth were significant for DMV (p<0.05), LNM, SN and obstructive sleep apnea for DL (p<0.05), and LNM and SN for DMV+DL (p<0.05). However, a 10-point increase of BMI was not an independent risk factor when patients with BMI >25% were considered. In conclusion, LNM and SN are independent risk factors for developing DMV and/or DL in obese endometrial cancer patients, while BMI increase over 30 was not additionally affecting difficult airway.

Ophthalmologe, Jul 4, 2015

Die Frühgeborenenretinopathie ("retinopathy of prematurity", ROP) ist einer der wichtigsten Gründ... more Die Frühgeborenenretinopathie ("retinopathy of prematurity", ROP) ist einer der wichtigsten Gründe für eine schwere Sehbehinderung/Erblindung im Kindesalter. Frühgeborene mit oder ohne ROP-Anamnese können im Gegensatz zu termingeborenen Kindern auch bei einem ophthalmoskopisch unauffälligen Fundus schlechtere Sehleistung aufweisen [23, 26]. Untersuchungen mittels optischer Kohärenztomographie (OCT) haben gezeigt, dass Frühgeborene im Gegensatz zu termingeborenen Kindern unabhängig von ROP eine vor allem makular gelegene dickere Retina aufweisen. Bei Frühgeborenen vor der 28. Gestationswoche wurde eine Störung der Migration von inneren Netzhautschichten der Fovea festgestellt [24]. Bei Ratten wurde im sauerstoffinduzierten Retinopathiemodell in der zentralen Aderhaut und in der Choriokapillaris eine unzureichend ausgebildete Gefäßstruktur und somit eine choroidale Involution festgestellt. Die choroidale Involution kann dazu führen, dass die äußeren Netzhautschichten nicht genügend mit Sauerstoff und Nährstoffen versorgt werden. Die reduzierte Perfusion kann zu einem Verlust der darüberliegen

Journal of Orthopaedic Science, 2021

BACKGROUND The use of a minimal individualized effective pneumatic tourniquet pressure is recomme... more BACKGROUND The use of a minimal individualized effective pneumatic tourniquet pressure is recommended to avoid pressure related complications in extremity surgery. The aim of this study was to investigate the efficacy of arterial occlusion pressure estimation-based tourniquet pressure settings in upper limb surgery. METHODS Hundred and fifteen patients undergoing upper limb surgeries were enrolled in the present study. Arterial occlusion pressure estimation formula was used and a safety margin of 20 mmHg was added to arterial occlusion pressure in the tourniquet pressure setting. Primary and secondary endpoints were the amount of tourniquet pressure and its effectiveness respectively. Other outcome measures included the tourniquet pressure setting time and tourniquet related complications. Surgical team unaware of the tourniquet pressure assessed the bloodless surgical field. RESULTS The mean initial and maximal tourniquet pressures were 171.5 ± 13.7 and 175.5 ± 13.2 mmHg, respectively. The effectiveness of the tourniquet was rated as "excellent" and "good" in the initial and middle stages, and at the end of the surgery of the procedure in 97.3%, 99.1%, and 100% of cases respectively. The mean tourniquet pressure setting time was 29.0 ± 3.7 s. No tourniquet related complications were observed. CONCLUSIONS Arterial occlusion pressure estimation-based tourniquet pressure setting is a practical and effective method, which allows using lower tourniquet pressures than previously used in the literature for upper extremity surgery.

Anaesthesia and Intensive Care, 1999

Intracranial subdural haematoma is a rare complication of spinal anaesthesia. This report describ... more Intracranial subdural haematoma is a rare complication of spinal anaesthesia. This report describes the case of a 31-year-old woman who presented with post partum headache following spinal anaesthesia for caesarean section. Bilateral haematomata were evacuated via burr-holes performed under total intravenous anaesthesia and the patient made a complete and uneventful recovery. The recognized causes of subdural haematoma are discussed.

Transplantation Proceedings, 2002

I SCHEMIA-reperfusion (I/R) injury is known to impair renal function. Loss of renal tubular epith... more I SCHEMIA-reperfusion (I/R) injury is known to impair renal function. Loss of renal tubular epithelium due to various cellular mechanisms is a major contributor to the development and progression of I/R-induced acute renal failure. 1-7 Within the heterogeneous renal cell population, the proximal tubule and the ascending limb of Henle are known to be most sensitive to prolonged ischemia. 1,3,4 The cellular injury following an I/R to the renal vascular bed is mediated by lipid peroxidation. Among the products of lipid peroxidation malondialdehyde (MDA), 4-hydroxynonenal (4-HNE), and conjugated dienes are widely used as markers of oxidative stress. The cellular defense against reactive oxygen species (ROS) that mediate oxidative stress is provided by enzymatic (catalase, superoxide dismutases, glutathione peroxidase) and nonenzymatic (glutathione, urate, vitamin E) scavenging systems. 2,5,8-12 Recently attention has focused on the contribution of nitric oxide (NO) and peroxynitrite in the pathogenesis of acute renal impairment and as mediators of oxidative stress. 9,13,14 L-arginine is known to be the sole substrate in the production of NO which is mediated through a reaction catalyzed by nitric oxide synthase (NOS). 15,16 In addition,

Cureus, Jul 13, 2023

Background Postoperative acute kidney injury (AKI) is an important cause of mortality and morbidi... more Background Postoperative acute kidney injury (AKI) is an important cause of mortality and morbidity among surgical patients. There is little information on the occurrence of AKI after operations for gynecologic malignancies. This study aimed to determine the incidence of AKI in patients who underwent surgery for gynecological malignancies and determine the risk factors in those who developed postoperative AKI. Methodology A total of 1,000 patients were enrolled retrospectively from January 2007 to March 2013. AKI was defined according to the Kidney Disease Improving Global Outcomes 2012 Clinical Practice Guideline for Acute Kidney Injury. Perioperative variables of patients were collected from medical charts. Results The incidence of postoperative AKI was 8.8%, with stage 1 occurring in 5.9%, stage 2 in 2.4%, and stage 3 in 0.5% of the patients. Patients who had AKI were significantly older, had higher body mass index (BMI) higher preoperative C-reactive protein (CRP) levels, and more frequently had a history of distant organ metastasis when compared with those who did not have AKI. When compared with patients who did not develop AKI postoperatively, longer operation times and intraoperative usage of higher amounts of erythrocyte suspension and fresh frozen plasma were seen in those who developed AKI. Conclusions Patients who had AKI were older, had higher BMI with higher preoperative CRP levels, more frequent distant organ metastasis, longer operation times, and higher amounts of blood transfused intraoperatively. Defining preoperative, intraoperative, and postoperative risk factors for postoperative AKI and taking necessary precautions are important for the early detection and intervention of AKI.

2. Ulusal Deneysel Cerrahi Kongresi, 2003

Critical Care, 2017

Introduction: Ventricular septal rupture (VSR) is an unusual mechanical complication of myocardia... more Introduction: Ventricular septal rupture (VSR) is an unusual mechanical complication of myocardial infarction (MI) in the era of reperfusion therapy, but the mortality rate of patients who present with cardiogenic shock (CS) remains extremely high. Whereas current American and European guidelines recommend urgent surgical repair regardless of hemodynamic status, promising outcomes have been repeatedly reported with the use of circulatory support, enabling hemodynamic stabilization and delaying repair after consolidation of the infarct scar. Therefore, we analyzed our experience with the use of Veno-Arterial Extracorporeal Membrane Oxygenation (V-A ECMO) in post-infarction VSR. Methods: We conducted a retrospective search of institutional database of all patients presenting with post-infarction VSR from January 2007 to June 2016. Data of 33 consecutive patients were retrospectively reviewed and analyzed. Results: In our center, 7 out of 33 patients with post-MI VSR and refractory CS (despite vasopressor and intraaortic balloon pump therapy) received V-A ECMO support. V-A ECMO improved end-organ perfusion with lower lactate levels 24 hours after implantation (7.514 vs. 1.514, p < 0.005), normalized arterial pH (7.25 vs. 7.40, p < 0.036), improved mean arterial pressure (64 mm/Hg vs. 83 mm/Hg, p < 0.001) and lowered heart rate (115/min vs. 68/min, p < 0.001) in all patients. Mean duration of ECMO support was 12 days, 5 out of 7 patients underwent surgical repair, 4 were successfully weaned from ECMO, 3 survived 30 days and 2 survived more than 1 year. The most frequent complication (5 patients) as well as the cause of death (3 patients) was bleeding. Conclusions: Our experience suggest that V-A ECMO support in patients with VSR and refractory CS improves end-organ perfusion, provides hemodynamic stabilization and increases time for cardiovascular team decision. Bleeding complications are an important limitation of this method.

International Journal of Oral and Maxillofacial Surgery, 2015

The aim of this study was to determine the effect of surgical mandibular backward movements on th... more The aim of this study was to determine the effect of surgical mandibular backward movements on the predictors of a difficult airway. Thirty-seven skeletal class III patients were included in this study. The Mallampati score, body mass index (BMI), maximal inter-incisal distance, and thyromental and sternomental distances of these patients were evaluated preoperatively and at 6 months and 2 years postoperatively. A sagittal split ramus osteotomy (SSRO) without genioplasty was performed in all patients by the same surgical team, and anaesthesia was provided by the same anaesthesiologist using nasotracheal intubation. The paired samples t-test and Wilcoxon signed-rank test were used for statistical comparisons of the data. There were no statistically significant changes in BMI or sternomental and thyromental distances after SSRO. The maximal inter-incisal distance was significantly reduced at 6 months postoperatively (P<0.05), but no statistical difference was found between the values obtained preoperatively and at 2 years postoperative. A statistically significant increase in Mallampati score was observed postoperatively (P<0.05). Both the patient and practitioner should be aware of the risks associated with an increased postoperative Mallampati score in mandibular setback patients. The amount of mandibular setback in skeletal class III patients with a high preoperative Mallampati score should be limited to prevent potential postoperative airway problems.

Transplantation Proceedings, 2003

European Journal of Anaesthesiology, 2011

Background and Goal of Study: Propofol concentrations are higher at loss of consciousness LOC tha... more Background and Goal of Study: Propofol concentrations are higher at loss of consciousness LOC than at return ROC1. This suggests drug hysteresis between LOC and ROC. Permutation entropy PeEn can indicate the hypnotic component of anaesthesia. Specific EEG frequencies may be used for dif ferent processing tasks, i.e β-oscillations (12-24Hz) seem to process information corticocortically while θ (4-8Hz) and α (8-12Hz) can be associated to the corticothalamocortical (CTC) loop. In order to reveal information about possible underlying mechanisms for LOC and ROC, PeEn of the frequency bands was calculated in the transition phases of LOC and ROC. Working hypothesis of this work is that there is hysteresis in propofol induced changes of cortical activity that can be detected with PeEn, i.e. PeEn values at LOC and ROC are not identical. Materials and Methods: EEG of 38 LOC and 33 ROC transitions with propofol obtained during two studies was evaluated with PeEn (d=5) in 4s steps starting 300s before until 300s af ter the event. Artefacts were visually identified and removed from analysis. PeEn was calculated for the δ(0.5-4Hz), θ, α, β and γ(24-47Hz) band. Therefore EEG was filtered with 3rd order Butterworth bandpass. Ef fect site concentration was assessed with a Schnider model2. The time interval between event and the time point were PeEn af ter LOC was equal to PeEn af ter ROC, i.e. where cortical activity was in the same state, was defined as time delay. Results and Discussion: PeEn(δ) and PeEn(θ) showed same values 96100s af ter the events. PeEn(α) was identical 40-44s af ter LOC/ROC. PeEn(β) values were already identical 4-0s before the events took part and PeEn (γ) was even faster with 12-8s before the event. Averaged Cef f was higher at LOC (3.73±1.51μg/ml) than at ROC (1.25±0.44μg/ml). PeEn(β) and PeEn(γ) showed same values, i.e. represented the same activity, before the events in contrast to slower frequency bands. Observation of PeEn courses reveals an almost “switch-like” change of PeEn(γ) and PeEn(β) at the events and can be associated with a change between consciousness and unconsciousness. At slower frequencies the course is more continuous. Conclusion: These findings lead to the conclusion that intraand corticocortical anaesthetic ef fects are triggered faster and more abrupt by propofol than CTC and corticohippocampal ef fects that are represented by slower oscillations. References: 1Prog Biophys Mol Biol 2004; 85:369-85 2Anesthesiology 1999; 90:1502-16