Baraka 1989.
| Methods | Study design: randomized parallel groups Study dates: not stated |
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| Participants | Country: Lebanon Sex: female Age: mean age 31 ASA: not available, "healthy" Procedure: caesarean section Study size: 50 |
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| Interventions |
Randomized portion of anaesthetic: parts of intravenous (IV) vs parts of volatile agent/N2O ± Intervention 1: induction: thiopentone 4 mg/kg; maintenance: N2O 50% + halothane 0.5% in O2, N = 10 Intervention 2: induction: thiopentone 4 mg/kg; maintenance: halothane 1% in O2, N = 10 Intervention 3: induction: ketamine 1.5 mg/kg; maintenance: 50% N2O + 0.5% halothane in O2, N = 10 Intervention 4: induction: ketamine 1.5 mg/kg; maintenance: 1% halothane in O2, N = 10 Intervention 5: induction: ketamine 1.5 mg/kg; maintenance: 100% O2, N = 10 |
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| Outcomes | Primary outcomes: APGAR, blood loss maternal artery PO2 (kPa), PCO2 (kPa), umbilical vein PO2 (kPa), PCO2 (kPa) Secondary outcome: awareness/wakefulness as defined using an awareness classification system (see Table 1): class 4 Quote: "Awareness following induction of anaesthesia was detected using isolated forearm technique" Comment: in this review this is referred to as "wakefulness"; "recall" is used by the authors as patient memory of postoperative events (awareness) Table 1 p646: "awareness" (wakefulness) 18 (14 in thiopentone and 4 in ketamine groups) patients, "recall" (awareness) 2 patients, intraoperative dreams 1, intraoperative hallucination 1 (classified as dream; both dreams in ketamine group) "Two of the 20 thiopentone patients had recall, confined to the time of delivery" |
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| Notes |
Non‐randomized portion of anaesthetic: parts of intravenous (IV) vs parts of volatile agent/narcotics/hypnotics bolus/muscle relaxants induction yes/maintenance yes Anaesthetic induction: suxamethonium 1.5 mg/kg After delivery ‐ anaesthetic maintenance: 66 N2O in O2 + fentanyl 3 µg/kg/alcuronium 0.25 mg/kg Time of outcome determination: following recovery and the next day Method of outcome determination: interview "Awareness following induction of anaesthesia was detected using the isolated forearm technique...Following tracheal intubation, the patient's right hand was clasped by the anaesthetist and the patient was asked to squeeze and relax her hand three times successively... Because hand movement may occur spontaneously or as a response to surgical stimulation, the test was considered positive only if the patient squeezed and relaxed her hand according to instructions" ROB survey see Baraka 1998: the Cochrane Anaesthesia, Critical and Emergency Care Group's editorial team prefers not to extrapolate to previously published RCTs in assigning ROB risk |
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| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Unclear risk | Quote: "The 50 patients were allocated randomly to five equal groups" |
| Allocation concealment (selection bias) | Unclear risk | Comment: no information provided |
| Blinding of participants and personnel (performance bias) All outcomes | Unclear risk | Comment: no information provided |
| Blinding of outcome assessment (detection bias) All outcomes | Unclear risk | Comment: insufficient information provided |
| Incomplete outcome data (attrition bias) All outcomes | Low risk | Comment: no dropout |
| Selective reporting (reporting bias) | Low risk | Comment: awareness outcome part of inclusion criteria |
| Other bias | Unclear risk | Comment: insufficient information provided |