Transfusion trigger--how precise are we? Intraoperative blood transfusion practices in a tertiary centre in Nigeria.

SUMMARY: To determine how well anaesthetists in Nigeria determine the need for transfusion based solely on physiological variables and estimated blood loss. To determine the incidence of inappropriate blood transfusion. Anaesthetists in our hospital determine when to transfuse patients based solely on clinical acumen. This may result in inappropriate transfusion especially in this subregion where blood donors are scarce and risk of transmission of infection high. All surgical patients requiring blood transfusion were prospectively studied over 3 months. Transfusion was based solely on the discretion of the attending anaesthetist. Haemoglobin (Hb) concentration was measured prior to transfusion and 24 h postoperatively. Appropriate transfusion was defined as blood transfusion at Hb < 8 g dL(-1) or 10 g dL(-1) in the elderly and those with medical comorbidities. The trigger for transfusion was documented as well as estimated blood loss. Thirty-four patients were studied. The mean pretransfusion Hb was 8.09 +/- 2.45 g dL(-1) (range 4.6-14.2). Twenty-one patients (61.8%) had appropriate blood transfusion. The commonest transfusion triggers were clinical pallor (82.4%), excessive blood loss (76.4%), delayed capillary refill (55.9%) and severe hypotension (50%). The use of near patient monitoring devices might further improve blood transfusion practice in this setting where donor blood is scarce.

Pre-induction hypokalaemic phenomenon in Nigerian adult population.

BACKGROUND: Anaesthesia in the perioperative period is characterized by acute changes in plasma potassium (K+) which may be caused by anxiety. Anxiety leads to an intracellular shift of potassium which may lead to hypokalaemia. These fluctuations in plasma potassium may sometimes induce arrhythmias. This study was designed to determine the acute changes in plasma potassium levels in the immediate pre-induction period in a sample of Nigerian patients and to determine the incidence of arrhythmias correlating with these changes. METHODS: Sixty ASA I and II adults aged 14 to 70 years, both genders, undergoing elective surgery under general anaesthesia at the Lagos University Teaching Hospital were prospectively and consecutively recruited. Preoperative plasma potassium level was determined 1-3 days before surgery. Premedication was with oral diazepam 10-20 mg given nocte and on the morning of surgery. Pre-induction plasma potassium level was determined within 5 minutes before induction of anaesthesia. RESULTS: Mean preoperative K+ was 3.98 +/- 0.38 mEq.L(-1) (range of 3.5 - 4.9 mEqL(-1)). The mean pre-induction plasma K+ level was 3.01 +/- 0.35 mEq.L(-1) (range of 2.1 - 3.6). This represented a fall of 24% (0.97 +/- 0.39 mEq.L(-1)) which was significantly different (p < 0.001). More than 80% of the patients exhibited some fall in plasma K+. No arrhythmias were recorded during the study period. CONCLUSION: Pre-induction hypokalaemia occurred frequently despite the administration of anxiolysis with diazepam. There is a need to consider this phenomenon and measure K+ levels immediately pre-induction especially in patients with existing borderline normal K+ levels.