α-2 agonists vs. fentanyl as adjuvants for spinal anesthesia in elective cesarean section: a meta-analysis.

INTRODUCTION: Elective cesarean section (CS) is usually performed using spinal anesthesia (SA), which requires the use of local anesthetic (LA) agents, commonly combined with adjuvant drugs. We performed a systematic review and meta-analysis aimed at studying the advantages of α-2 agonists as compared to fentanyl during SA for CS. EVIDENCE ACQUISITION: We screened PubMed and EMBASE for randomized controlled trials (RCTs). We calculated the mean difference (MD) for continuous outcomes, and the relative risk for dichotomous outcomes, using a random-effect model with 95% confidence interval (CI). We performed a Trial Sequential Analysis (TSA) assuming an alpha risk of 5%. The primary outcome was the time to first rescue analgesia. EVIDENCE SYNTHESIS: Eight RCTs were included. Time to first rescue analgesia was significantly longer when the α-2 agonists were used (MD 85.9 min [95% CI: 23.8, 147.9]; P=0.007). Duration of sensory block was also longer in the α-2 group (MD 40.5 [95% CI: 20.21,60.7]; P<0.0001), while no differences were found for onset of sensory block and onset and duration of motor block. Rates of shivering and nausea or vomiting were significantly lower in the α-2 agonist group, while risk of hypotension or respiratory depression were not different. The TSA on the primary outcome suggests the need of further research before drawing conclusions. CONCLUSIONS: α2-agonists seem to increase the time to first rescue analgesia and to prolong the duration of sensory block when used as adjuvants to LA in CS patients compared to fentanyl. Also, α2-agonists may reduce the incidence of shivering and nausea or vomiting.

Caution Is Warranted When Assessing Diastolic Function Using Transesophageal Echocardiography. Comment on Kyle et al. Consensus Defined Diastolic Dysfunction and Cardiac Postoperative Morbidity Score: A Prospective Observational Study. J. Clin. Med. 2021, 10, 5198.

Kyle et al. [...].

The effects of exposure to severe hyperoxemia on neurological outcome and mortality after cardiac arrest.

INTRODUCTION: Hyperoxemia during cardiac arrest (CA) may increase chances of successful resuscitation. However, episodes of severe hyperoxemia after intensive care unit admission occurs frequently (up to 60%), and these have been associated with higher mortality in CA patients. The impact of severe hyperoxemia on neurological outcome is more unclear. EVIDENCE ACQUISITION: We conducted a systematic review and meta-analysis on Pubmed and EMBASE to evaluate the effects of severe hyperoxemia according to arterial blood gas analysis on neurological outcome and mortality in patients resuscitated from CA and admitted to intensive care unit. EVIDENCE SYNTHESIS: Thirteen observational studies were included, eight of them reporting data on neurological outcome and ten on mortality. Most studies reported odds ratio adjusted for confounders. Severe hyperoxemia was associated with worse neurological outcome (OR 1.37 [95%CI 1.01,1.86], P=0.04) and higher mortality at longest follow-up (OR 1.32 [95%CI 1.11,1.57], P=0.002). Subgroup analyses according to timing of hyperoxemia showed that any hyperoxemia during the first 36 hours was associated with worse neurological outcome (OR 1.52 [95%CI 1.12,2.08], P=0.008) and higher mortality (OR 1.40 [95%CI 1.18,1.66], P=0.0001), whilst early hyperoxemia was not (neurological: P=0.29; mortality: P=0.19). Sensitivity analyses mostly confirmed the results of the primary analyses. CONCLUSIONS: Severe hyperoxemia is associated with worse neurological outcome and lower survival in CA survivors admitted to intensive care unit. Clinical efforts should be made to avoid severe hyperoxemia during at least the first 36 hours after cardiac arrest.

Targeted Temperature Management after Cardiac Arrest: A Systematic Review and Meta-Analysis with Trial Sequential Analysis.

Target temperature management (TTM) in cardiac arrest (CA) survivors is recommended after hospital admission for its possible beneficial effects on survival and neurological outcome. Whether a lower target temperature (i.e., 32-34 °C) improves outcomes is unclear. We conducted a systematic review and meta-analysis on Pubmed and EMBASE to evaluate the effects on mortality and neurologic outcome of TTM at 32-34 °C as compared to controls (patients cared with "actively controlled" or "uncontrolled" normothermia). Results were analyzed via risk ratios (RR) and 95% confidence intervals (CI). Eight randomized controlled trials (RCTs) were included. TTM at 32-34 °C was compared to "actively controlled" normothermia in three RCTs and to "uncontrolled" normothermia in five RCTs. TTM at 32-34 °C does not improve survival as compared to normothermia (RR:1.06 (95%CI 0.94, 1.20), p = 0.36; I2 = 39%). In the subgroup analyses, TTM at 32-34 °C is associated with better survival when compared to "uncontrolled" normothermia (RR: 1.31 (95%CI 1.07, 1.59), p = 0.008) but shows no beneficial effects when compared to "actively controlled" normothermia (RR: 0.97 (95%CI 0.90, 1.04), p = 0.41). TTM at 32-34 °C does not improve neurological outcome as compared to normothermia (RR: 1.17 (95%CI 0.97, 1.41), p = 0.10; I2 = 60%). TTM at 32-34 °C increases the risk of arrhythmias (RR: 1.35 (95%CI 1.16, 1.57), p = 0.0001, I2 = 0%). TTM at 32-34 °C does not improve survival nor neurological outcome after CA and increases the risk of arrhythmias.

Controlled hypotension during middle ear surgery: hemodynamic effects of remifentanil vs nitroglycerin.

INTRODUCTION: Controlled hypotension is a well-known technique used by anesthesiologists to limit intraoperative bleeding in patients undergoing middle ear surgery and improve visibility of the surgical field. Nitroglycerin and remifentanil are among the drugs used to induce controlled hypotension.The aim of our study was to compare the hemodynamic effects of remifentanil and nitroglycerin in this patient population. METHODS: All consecutive patients who underwent middle ear surgery between January and December 2016, at the University Hospital Vittorio Emanuele in Catania were included in a retrospective study. Patients who were given nitroglycerin to induce controlled hypotension were compared to those given remifentanil. The following parameters were measured systolic and diastolic blood pressure, heart rate, peripheral (capillary) oxygen saturation, and fraction of expired carbon dioxide. A mean arterial pressure of 50-70 mmHg was considered optimal. RESULTS: Thirty patients who underwent stapedioplasty and tympanoplasty, 25 men and 5 women,with a mean age of 43 years (range 32-58 years) were included in the study. Fifteen patients had received nitroglycerin (group A) and 15 patients remifentanil (group B). The target blood pressure was reached in all patients and no significant difference was found between the groups with regard to the level of systolic and diastolic blood pressure, heart rate, peripheral (capillary) oxygen saturation, and fraction of expired carbon dioxide. However the heart rate of 2 younger patients in group A rose to > 100 bpm after the administration of nitroglycerin. CONCLUSION: Both remifentanil and nitroglycerin are effective in inducing controlled hypotension. In younger patients administration of nitroglycerin is associated with an increase in heart rate. KEY WORDS: Controlled hypotension, Middle ear surgery, Nitroglycerin, Remifentanil.