Nenad Karanović

Rocuronium attenuates oculocardiac reflex during squint surgery in children anesthetized with halothane and nitrous oxide

Background:  The oculocardiac reflex (OCR) may be activated during squint surgery. The aim of this study was to test whether rocuronium 0.4 mg kg−1 could reduce the frequency of OCR, and also whether a single dose of succinylcholine 1 mg kg−1 could affect the frequency of OCR during anesthesia with halothane in a nitrous oxide/oxygen mixture.

Association of oculocardiac reflex and postoperative nausea and vomiting in strabismus surgery in children anesthetized with halothane and nitrous oxide.

Background:  Postoperative nausea and vomiting (PONV) occurs frequently after strabismus surgery. The controversy still exists regarding the association of PONV and the oculocardiac reflex (OCR). A recent study has proven that rocuronium attenuates OCR. If these two occurrences are dependent, it is expected that with the diminution of OCR, occurrence of PONV will also be reduced. The goal of this randomized, controlled study was to prove an association between OCR and PONV by attenuating OCR with 0.4 mg·kg−1 of rocuronium and subsequently diminishing PONV if these occurrences are associated.

Propofol abolished the phrenic long-term facilitation in rats

The aim was to investigate the effect of propofol anesthesia on the phrenic long-term facilitation (pLTF) in rats. We hypothesized that pLTF would be abolished during propofol-compared with urethane anesthesia. Fourteen adult, male, anesthetized, vagotomized, paralyzed, and mechanically ventilated Sprague-Dawley rats (seven per group), were exposed to the acute intermittent hypoxia (AIH) protocol. Peak phrenic nerve activity (PNA), burst frequency (f), and breathing rhythm parameters (Ti, Te, Ttot) were analyzed during the first hypoxia (TH1), as well as at 15 (T15), 30 (T30), and 60min (T60) after the final hypoxic episode, and compared to the baseline values. In propofol-anesthetized rats no significant changes of PNA were recorded after the last hypoxic episode, i.e. no pLTF was induced. There was a significant increase of PNA (59.4+/-6.6%, P<0.001) in urethane-anesthetized group at T60. AIH did not elicit significant changes in f, Ti, Te, Ttot in either group at T15, T30, and T60. The pLTF, elicited by AIH, was induced in the urethane-anesthetized rats. On the contrary, pLTF was abolished in the propofol-anesthetized rats.

The acute hypoxic ventilatory response under halothane, isoflurane, and sevoflurane anaesthesia in rats*

The relative order of potency of anaesthetic agents on the hypoxic ventilatory response has been tested in humans, but animal data are sparse. We examined the effects of 1.4, 1.6, 1.8, and 2.0 MAC halothane, isoflurane, and sevoflurane on phrenic nerve activity in euoxia (baseline) and during acute normocapnic hypoxia (inspired oxygen fraction 0.09) in adult male Sprague‐Dawley rats. With halothane, all animals became apnoeic even in euoxia, and the hypoxic response was completely abolished at all anaesthetic levels. With isoflurane, 5 of 14 animals exhibited phrenic nerve activity in euoxia at 1.4 MAC and demonstrated a hypoxic response (302% of baseline activity), but all became apnoeic and lost the hypoxic response at higher doses. With sevoflurane, phrenic nerve activity and a hypoxic response was preserved in at least some animals at all doses (i.e. even the highest dose of 2.0 MAC). Similar to the rank order of potency previously observed in humans, the relative order of potency of depression of the hypoxic ventilatory response in rats was halothane (most depressive) > isoflurane > sevoflurane (p = 0.01 for differences between agents).

Sevoflurane and isoflurane monoanesthesia abolished the phrenic long-term facilitation in rats

Phrenic long-term facilitation (pLTF) is a form of respiratory plasticity, manifested by prolonged increase in peak amplitude of phrenic nerve activity (PNA) after episodes of acute intermittent hypoxia (AIH). The aim was to investigate the effects of sevoflurane and isoflurane monoanesthesia at equipotent anesthetic doses on the expression of amplitude pLTF. Experiments were performed on Sprague-Dawley anesthetized, vagotomized, and mechanically ventilated rats. Two experimental groups, sevoflurane and isoflurane, and a control group (urethane-anesthetized) were formed. Peak amplitude of phrenic nerve activity, respiratory frequency and breathing rhythm parameters (Ti, inspiratory duration; Te, expiratory duration; and Ttot, total respiratory time duration) were analyzed during hypoxic episodes, and at 15, 30, and 60min after the last hypoxic episode. In the control group average PNA increased by 173.03±70.16% (p<0.001), at 60min after the last hypoxic episode compared to baseline values. Therefore amplitude pLTF was induced. In the sevoflurane and isoflurane groups PNA failed to increase, and in fact decreased by 15.79±15.18% and 31.00±11.00%, respectively (p>0.05). Amplitude pLTF was abolished during sevoflurane and isoflurane monoanesthesia.

Intravenous anaesthesia for adenoidectomy in a 3-year-old child with Kartagener syndrome and sleep disordered breathing

Kartagener syndrome (KGS) is a rare inherited disorder characterized by situs inversus viscerum (including dextrocardia) and primary ciliary dyskinesia resulting in chronic respiratory tract infections, bronchiectasis and sinusitis. Possible anesthesiologic challenges are related to the respiratory system and increased susceptibility to infectious complications. There are several case reports of general anesthesia in these patients, but mainly in the adult population . Here, we report on a 3-year old female child with KGS, who underwent adenoidectomy because of sleep disordered breathing (SDB). Preoperative preparation consisted of intravenous antibiotics, steroids, as well as postural drainage and inhalations of bromhexine and salbutamol. Anesthesia was induced with propofol, fentanyl and vecuronium and maintained with a continuous infusion of propofol (150-200 �g kg-1min-1) and supplemental doses of fentanyl. The child was ventilated with oxygen/air mixture (50%:50%) in the pressure-controlled mode of ventilation to keep end-tidal CO2 between 30 and 35 mmHg. During anesthesia the child’s hemodynamic and respiratory parameters were stable. Extubation, after thorough endotracheal and oral suction, was uneventful. After two hours in the post-anaesthesia care unit (PACU), the child was transferred to the ward. To the best of our knowledge, this is the youngest reported child with KGS and SDB that underwent intravenous general anesthesia. We also stress here the importance of comprehensive pre-anesthetic preparation, i.e. postural drainage, inhalations, bronchodilators, i.v. antibiotics and steroids. Furthermore, the condition of the respiratory system in the patient with KGS is seldom appropriate at the time of surgery, so the decision to anesthetize or not, should be made on an individual basis.

A Prospective Cohort Evaluation of the Cortisol Response to Cardiac Surgery with Occurrence of Early Postoperative Cognitive Decline

Background A recent study reported that patients with higher cortisol levels on the 1st postoperative morning after cardiac surgery exhibited an increased risk of early postoperative cognitive decline (POCD). Therefore, we conducted the current study to gain further insight into the stress response to a surgical procedure as a potential risk factor for early POCD after cardiac surgery. Material/Methods This prospective cohort study enrolled 125 patients undergoing elective cardiac surgery with or without cardiopulmonary bypass (CPB). Patient serum cortisol levels were determined 1 day before surgery (at 08: 00) and on the 1st (at 08: 00, 16: 00 and 24: 00), 3rd (at 08: 00), and 5th (at 08: 00) postoperative days. A battery of 9 neuropsychological tests were used to assess the participants 2 days before the surgical procedure and on the 6th postoperative day. POCD was defined as a decrease in performance of 1 SD or greater between the postoperative and preoperative z scores on at least 1 neuropsychological test. A mixed-design ANOVA was used to determine the correlations of the perioperative cortisol levels with the occurrence of POCD and with the surgical technique performed. Results Mixed-design ANOVA showed no statistically significant differences in the cortisol levels between non-POCD and POCD patients (F=0.52, P=0.690) or between patients with and without CPB (F=2.02, P=0.103) at the 6 perioperative time points. Conclusions The occurrence of early POCD and the use of CPB were not associated with significantly higher cortisol levels in the repeated measurement design.

Intracoronary administration of levosimendan in patients with acute coronary syndromes and decreased left ventricular ejection fraction undergoing coronary artery bypass graft surgery

In cardiac surgery patients, intracoronary (IC) administration of levosimendan can provide optimal drug spread, enabling effective manifestation of favorable drug effects and avoiding potentially harmful systemic hypotension. This could be beneficial in acute coronary syndromes (ACS) with decreased left ventricular ejection fraction (LVEF). We present ten cases of IC administration of levosimendan in ACS manifested as ST segment elevation myocardial infarction, non-ST segment elevation myocardial infarction or unstable angina pectoris. All patients underwent coronary artery bypass graft (CABG) surgery, performed as an “off-pump” or “onpump”/“off-clamp” procedure (latter one with the use of cardiopulmonary bypass on the beating heart). Levosimendan was administered as an IC bolus (125-250 μg) in each coronary artery graft (2-3 grafts). Intravenous (IV) levosimendan infusion continued (0.1-0.2 μg•kg-1•min-1) after graft placements (24-48 h), with IV infusion of norepinephrine (0.1 mg•ml-1), if needed. Cardiac function was assessed using LVEF (%) (Teicholz), thermodilution cardiac index (CI) (ml•m-2), and systemic vascular resistance (SVR) (dynes•sec•cm-5). Nonparametric Wilcoxon signed-ranks test [presented as median (MED) with interquartile range (IQR)] indicated a significant difference between preoperative vs. immediate postoperative CI, SVR, and LVEF in all cases [2.2 (1.9-2.5) vs. 3.1 (2.93.4) ml•m-2, 1173.0 (1062.7-1278.2) vs. 882.5 (763.5-993.0) dynes•sec•cm-5, 44.5 (36.0-46.7) vs. 53.5 (45.7-59.2) %, respectively] (P=0.005), i.e. IC administration of levosimendan was associated with prompt improvement of intraoperative hemodynamics and cardiac contractility. IC administration of levosimendan may be a promising alternative method for improving decreased cardiac function in acute cardiac ischemia, besides necessary surgical revascularization.

Effects of dexamethasone on early cognitive decline after cardiac surgery: A randomised controlled trial

BACKGROUND Postoperative cognitive decline (POCD), a very common complication after cardiac surgery, is characterised by impairment of both memory function and intellectual ability as well as being associated with increased use of healthcare resources. The investigators focused on the role of the inflammatory response to a surgical procedure as a potential factor involved in the pathogenesis of POCD. OBJECTIVE The use of prophylactic dexamethasone to attenuate the inflammatory response was hypothesised to reduce the risk of POCD. DESIGN Randomised controlled study. SETTING Single university teaching hospital, from March 2015 to January 2016. PATIENTS A total of 169 patients scheduled for elective cardiac surgery were enrolled, and 161 patients were included in the analyses. INTERVENTION Patients were randomised to receive a single intravenous bolus of 0.1 mg kg−1 dexamethasone (n = 85) or placebo (n = 84) 10 h before the surgery. MAIN OUTCOME MEASURES The primary outcome measure in both groups was the incidence of POCD on the 6th day after surgery. The investigators also evaluated the effect of dexamethasone on the incidence of systemic inflammatory response syndrome, postoperative C-reactive protein levels and postoperative serum S100&bgr; protein levels. RESULTS Compared to the placebo group, the dexamethasone group showed statistically significant reductions in the incidence of POCD (relative risk, 0.43; 95% confidence interval, 0.21 to 0.89; P = 0.02), the incidence of systemic inflammatory response syndrome (30.0 versus 58.0%, P < 0.001) and postoperative C-reactive protein levels (P < 0.001). Postoperative S100&bgr; levels were insignificantly lower (P = 0.56) in the dexamethasone group. CONCLUSION Preoperative administration of dexamethasone reduced the inflammatory response and thereby decreased the risk of early POCD after cardiac surgery. TRIAL REGISTRATION Clinicaltrials.gov identifier: NCT02767713.

Thermal damage of internal thoracic artery and ultra high radiofrequency

The gold standard in left anterior descending branch coronary artery surgery is performing an internal thoracic artery (ITA)bypass.Seventy-four ITA specimens were divided into two groups depending on device used for harvesting (radiofrequency-knife (RF) or electrocauter (EC)). Demonstrated results suggest that the radiosurgery in comparison to conventional electrocautery could reduce thermal damage to the endothelial layer of ITA, compared to the conventional electrocautery and potentially optimize the quality of ITA bypass grafts.