Norepinephrine Infusion for Preventing Postspinal Anesthesia Hypotension during Cesarean Delivery: A Randomized Dose-finding Trial.

BACKGROUND: Norepinephrine has been recently introduced for prophylaxis against postspinal hypotension during cesarean delivery; however, no data are available regarding its optimum dose. The objective of this study is to compare three infusion rates of norepinephrine for prophylaxis against postspinal hypotension during cesarean delivery. METHODS: The authors conducted a double-blinded, randomized, controlled study including full-term pregnant women scheduled for cesarean delivery. Norepinephrine infusion was commenced after subarachnoid block. Patients were randomized into three groups, which received norepinephrine with starting infusion rates of 0.025 µg · kg(-1) · min(-1), 0.050 µg · kg(-1) · min(-1), and 0.075 µg · kg(-1) · min(-1). Infusion was stopped when intraoperative hypertension occurred. The primary outcome was the frequency of postspinal hypotension (defined as decreased systolic blood pressure less than 80% of the baseline reading). The three groups were compared according to the following: systolic blood pressure, heart rate, frequency of intraoperative hypertension, frequency of bradycardia, and neonatal outcomes. RESULTS: Two hundred eighty-four mothers were included in the analysis. The frequency of postspinal hypotension was lower for both the 0.050-µg · kg(-1) · min(-1) dose group (23/93 [24.7%], odds ratio: 0.45 [95% CI: 0.24 to 0.82], P = 0.014) and the 0.075-µg · kg(-1) · min(-1) dose group (25/96 [26.0%], odds ratio: 0.48 [95% CI:0.26 to 0.89], P = 0.022) compared with the 0.025-µg · kg(-1) · min(-1) dose group (40/95 [42.1%]). The two higher-dose groups (the 0.050-µg · kg(-1) · min(-1) group and the 0.075-µg · kg(-1) · min(-1) group) had higher systolic blood pressure and lower heart rate compared with the 0.025 µg · kg(-1) · min(-1) group. The three groups were comparable in the frequency of intraoperative hypertension, incidence of bradycardia, and neonatal outcomes. CONCLUSIONS: Both the 0.050-µg · kg(-1) · min(-1) and 0.075-µg · kg(-1) · min(-1) norepinephrine infusion rates effectively reduced postspinal hypotension during cesarean delivery compared with the 0.025-µg · kg(-1) · min(-1) infusion rate.

Thoracic fluid content: a novel parameter for detection of pulmonary edema in parturients with preeclampsia.

Acute pulmonary oedema is a serious complication of preeclampsia. Early detection of pulmonary edema in preeclampsia would improve fluid management and would also allow earlier detection of severe cases. The aim of this work is to evaluate the ability of thoracic fluid content measured by electrical cardiometry for early detection of pulmonary edema in parturients with preeclampsia. A prospective observational study included a cohort of preeclamptic parturients. On admission, lung ultrasound score was calculated, and thoracic fluid content was recorded using electrical cardiometry ICON device. Area under receiver operating characteristic (AUROC) curve was calculated for lung ultrasound score, thoracic fluid content for detection of pulmonary edema. Spearman correlation coefficient was calculated for correlation between lung ultrasound score and thoracic fluid content. Sixty patients were included in the study; of them, 6 patients (10%) required diuretics for pulmonary edema. Patients with pulmonary edema had higher lung ultrasound score and thoracic fluid content compared to other patients. Good correlation was reported between Lung ultrasound score and thoracic fluid content (r = 0.82). Thoracic fluid content and lung ultrasound score showed excellent diagnostic properties for pulmonary edema {AUROC: 0.941 (0.849-0.986), best cut-off value: 40 k ohm-1}, and {AUROC: 0.961 (0.887-0.994), best cut-off value of 15.7}. In parturients with preeclampsia, both lung ultrasound score and thoracic fluid content showed excellent properties for detection pulmonary edema. The high negative predictive value of both tests makes them useful screening tests to rule out pulmonary edema. The excellent correlation between both measures suggests that electrical cardiometry could be a promising surrogate to ultrasound for assessment of extravascular lung water.

Evaluation of the effects of dexmedetomidine infusion on oxygenation and lung mechanics in morbidly obese patients with restrictive lung disease.

BACKGROUND: Dexmedetomidine infusion improves oxygenation and lung mechanics in patients with chronic obstructive lung disease; however, its effect in patients with restrictive lung disease has not been thoroughly investigated yet. The aim of this work was to evaluate the effects of dexmedetomidine infusion on oxygenation and lung mechanics in morbidly obese patients with restrictive lung disease. METHODS: Forty-two morbidly obese patients scheduled for bariatric surgery were included in the study. Patients were randomized to receive either dexmedetomidine infusion at a bolus dose of 1mcg/Kg followed by infusion at 1 mcg/Kg/hour for 90 min (Dexmedetomidine group), or normal saline infusion (Control group). Both groups were compared with regard to: oxygenation {P/F ratio: PaO2/fraction of inspired oxygen (FiO2)}, lung compliance, dead space, plateau pressure, blood pressure, and heart rate. RESULTS: Dexmedetomidine group showed significant improvement of the PaO2/FiO2 ratio, and higher lung compliance compared to control group by the end of drug infusion. Dexmedetomidine group demonstrated decreased dead space, plateau pressure, blood pressure, and heart rate compared to control group by the end of drug infusion. CONCLUSION: A 90-min dexmedetomidine infusion resulted in moderate improvement in oxygenation and lung mechanics in morbidly obese patients with restrictive lung disease. TRIAL REGISTRATION: clinicaltrials.gov : NCT02843698 on 20 July 2016.

Addition of dexmedetomidine to bupivacaine for greater palatine nerve block prolongs postoperative analgesia after cleft palate repair.

BACKGROUND AND OBJECTIVE: The effect of dexmedetomidine on the duration of sensory blockade has not been studied in humans. We evaluated the effect of adding dexmedetomidine to bupivacaine on the duration of postoperative analgesia in children who underwent repair of a cleft palate. METHODS: Thirty children who were scheduled for repair of a complete cleft palate using a combination of general anaesthesia and greater palatine nerve block were allocated randomly into one of two equal groups (n = 15). In both groups, the greater palatine nerve block was performed bilaterally using 0.5 ml of solution on each side. The B group received bupivacaine 0.25%, whereas the BD group received bupivacaine 0.25% with 1 microg kg(-1) dexmedetomidine. Heart rate, systolic blood pressure, pain score, the time to the first request for analgesia, and the degree of sedation were recorded. RESULTS: There was no difference in haemodynamic variables between the two groups. The pain score was significantly higher in the B group as compared with the BD group. The time to the first request for analgesia was significantly longer in children in the BD group (mean 22 h, range 20.6-23.7 h) as compared with those who received bupivacaine alone (14.2 h, 13-15 h). Sedation scores in the postoperative period did not differ between the study groups. CONCLUSION: Greater palatine nerve block with a combination of dexmedetomidine and bupivacaine increased the duration of analgesia after repair of a cleft palate by 50% with no clinically relevant side effects.