Biomarker and isotopic characteristics of Miocene condensates and natural gases, West Delta deep marine concession, Eastern Mediterranean, Egypt.

The Western Delta Deep Marine Concession (WDDM) in the Eastern Mediterranean Sea is one of northern Africa's most recent petroleum-potential regions for gas and condensate exploration. The present study aims to determine the characteristics of the 15 natural gases and 5 associated condensate samples, using molecular compositions and isotopes from the Miocene reservoir rocks in the various wells located in the WDDM. The results of this study are also used to determine the gas-condensate correlation for their probable source rocks as well as the methane-generating mechanisms (i.e., thermogenic or microbiological). Results highlighted in this research reveal that most of the natural gases in WDDM are mainly thermogenic methane gases, with small contributions of biogenic methane gases that were generated from mainly mixed sources, with a high sapropelic organic matter input for biogenic gases. The thermogenic methane gases were formed from secondary oil and oil/gas cracking at the high maturity stage of the gas window. The biogenic gases are also contributed to the Miocene reservoirs, which are formed from the primary cracking of kerogen at low maturity stage by the action of CO2 bacterial reduction. In addition, the saturated and aromatic biomarker results show that the condensate samples were generated from clay-rich source rocks. This source unit of the Miocene condensates were deposited in a fluvial deltaic environmental setting, containing mixed kerogen type II/III and accumulated during the Jurassic-Cretaceous, as evidenced by the age dating indicators. The properties of the natural gases and associated condensates in the Miocene reservoir rocks suggest that most of the thermogenic methane gases, together with the condensate, are derived primarily from mature Jurassic-Cretaceous source rocks and formed by secondary oil and oil/gas cracking at the gas generation window, as demonstrated by the 1-D basin modelling results highlighted in the prior works. Therefore, most of the natural gases in WDDM are non-indigenous and migrated from more mature Jurassic-Cretaceous source rocks in the nearby Northern Sinai provinces or the deeper sequences in the offshore Nile Delta provinces.

Quality of lidocaine analgesia with and without midazolam for intravenous regional anesthesia.

PURPOSE: Midazolam has analgesic effects mediated by gamma aminobutyric acid-A receptors. This study was designed to evaluate the effect of midazolam on anesthesia and analgesia quality when added to lidocaine for intravenous regional anesthesia (IVRA). METHODS: Forty patients undergoing hand surgery were randomly assigned to two groups to receive IVRA. The control group received 3 mg/kg lidocaine 2% w/v diluted with saline to a total volume of 40 ml, and the midazolam group received an additional 50 µg/kg midazolam. Sensory and motor block onset and recovery times, tourniquet pain, intraoperative analgesic requirements, sedation, and anesthesia quality were recorded. Postoperative pain and sedation scores, time to first analgesic requirements, analgesic use in the first 24 h, and side effects were noted. RESULTS: Sensory and motor block onset and recovery times did not differ significantly between groups. Tourniquet pain scores were lower at 10, 15, 20, and 30 min (P < 0.0001) in the midazolam group. Three (15%) patients in the midazolam group required fentanyl for tourniquet pain compared with thirteen (65%) patients in the control group (P = 0.02). Patients in both groups received fentanyl once. Midazolam group showed that significantly less patients required diclofenac for postoperative analgesia (P < 0.01) and analgesic-free period during first postoperative 24 h was significantly longer (726.8 ± 662.8 min vs. 91.0 ± 35.9 min, P < 0.0001). Postoperative pain scores were lower (P < 0.0001) and sedation scores higher (P < 0.05) for the first 2 h in the midazolam group. CONCLUSION: Addition of midazolam to lidocaine for IVRA improves anesthesia quality and enhances intraoperative and postoperative analgesia without causing side effects.

A comparison of intra-articular magnesium and/or morphine with bupivacaine for postoperative analgesia after arthroscopic knee surgery.

PURPOSE: Both magnesium and morphine provide enhanced patient analgesia after arthroscopic knee surgery when administered separately via the intra-articular route. Magnesium sulfate amplifies the analgesic effect of morphine. This study was designed to compare the analgesic effects of intra-articular magnesium and morphine, with bupivacaine, when used separately and in combination. METHODS: Eighty patients undergoing arthroscopic menisectomy were randomized blindly into four intra-articular groups: group B+Mor+Mg received 20 ml 0.25% bupivacaine, morphine 2 mg, and magnesium 150 mg; group B+Mor received 20 ml 0.25% bupivacaine and morphine 2 mg; group B+Mg received 20 ml 0.25% bupivacaine and magnesium 150 mg; and group B received 20 ml 0.25% bupivacaine. Pain scores at rest and during movement, analgesic duration, and total analgesic consumption were recorded. RESULTS: Group B+Mor and group B+Mg patients had equally effective postoperative analgesia. Group B+Mor+Mg patients had significantly reduced visual analogue scale (VAS) values both at rest and during movement and significantly increased time to first postoperative analgesic request, as well as significantly reduced total analgesic consumption, compared with the other groups. CONCLUSION: Intra-articular administration of magnesium sulfate or morphine, with bupivacaine, had comparable analgesic effects in the doses used. Their combination provided more effective postoperative analgesia than either drug alone.

Ondansetron added to lidocaine for intravenous regional anaesthesia.

BACKGROUND AND OBJECTIVE: The aim of this study was to evaluate the effect of ondansetron when added to lidocaine for intravenous regional anaesthesia (IVRA). METHODS: Thirty patients undergoing hand surgery were randomly assigned to two groups. IVRA was achieved with 3 mg kg lidocaine 2% w/v diluted with saline to a total volume of 40 ml in the control group or with 4 mg ondansetron 2 mg ml plus 3 mg kg lidocaine 2% w/v diluted with saline to a total volume of 40 ml in the ondansetron group. Sensory and motor block onset and recovery times, tourniquet pain score according to a visual analogue scale (VAS), intraoperative analgesic requirements and anaesthesia quality were recorded. Postoperative VAS pain score, time to first analgesic requirements and total diclofenac consumption in the first 24 h were noted. RESULTS: Onset times were slightly but significantly shorter [1.4 min (95% confidence interval (CI) 0.5-2.3) and 1.5 min (95% CI 0.45-2.55)] and recovery times were slightly but significantly prolonged [2.6 min (95% CI 1.66-3.54) and 2.8 min (95% CI 1.83-3.78)] in patients receiving ondansetron. Tourniquet pain scores according to the VAS were slightly but significantly lower at 10, 15, 20 and 30 min, the time to intraoperative analgesic rescue was prolonged (35.0 +/- 7.1 min vs. 18.9 +/- 8.9 min, P = 0.043), a significantly lower number of patients (2 vs. 9) required additional analgesic and significantly less supplemental fentanyl was given [0 microg (0-0) vs. 59 microg (0-76), P = 0.015] in the ondansetron group. First intake of analgesic intake was longer (172 +/- 51 vs. 85 +/- 35 min, P = 0.0001), number of patients (7 vs. 15) requiring postoperative diclofenac was significantly lower and diclofenac requirements [0 mg (0-75) vs. 75 mg (75-150), P = 0.002) was significantly lower in the ondansetron group. Postoperative VAS scores were lower for the first 4 h in the ondansetron group. CONCLUSION: Addition of ondansetron to lidocaine may improve the quality of IVRA and prolong postoperative analgesia in patients undergoing hand surgery.