Influence of diuretics on brachial artery diameter and distensibility in hypertensive patients

Blood pressure, brachial artery diameter and pulse wave velocity were determined before and after diuretic treatment in 2 groups of hypertensive patients treated either by indapamide (2.5 mg per d) or by canreonate (50 mg per d). Brachial artery diameter, measured from pulsed Doppler flowmetry, and pulse wave velocity, evaluated from mechanography, did not alter significantly despite a significant blood pressure reduction. The study indicates that, in hypertensive patients of middle age, diuretics did not change brachial artery diameter and distensibility, whether the drug caused an increase or a decrease in plasma potassium levels.     

Reliability of maximal muscle force and voluntary activation as markers of exercise-induced muscle damage

The loss of the ability of skeletal muscle to generate force is one of the most appropriate and valid means to quantify muscle damage. Routine measurements of maximal muscle force, however, include many potential sources of error, the most important of which may be a possible lack of central drive to the muscles. The aim of the present study was to determine the reliability of maximal isometric quadriceps muscle force and voluntary activation over a timescale that is typically employed to examine the aetiology of exercise-induced muscle damage. We also attempted to characterise the reliability of several twitch interpolation variables including the size of the interpolated twitch and the state (i.e. unpotentiated vs potentiated) and size of the resting twitch. Over a 7-day period, eight healthy active males performed repeated maximal voluntary isometric contractions (MVC) of the quadriceps (baseline and 2 h, 6 h, 24 h, 48 h, 72 h and 7 days post). Systematic variations in maximal muscle force, voluntary activation, interpolated twitch, unpotentiated twitch and potentiated twitch were not statistically significant (P>0.05) and 95% repeatability coefficients of ±76.03 N, ±4.42%, ± 8.44 N, ±25.92 N and ±43.58 N were observed, respectively. These data indicate that young healthy well-familiarised male subjects can reproduce their perceived maximal efforts both within and between days where activation levels of >90% are routinely achieved. Providing activation remains within these limits in the 7 days following an acute bout of exercise, the researcher would be 95% certain that exercise-induced muscle damage is present in individual subjects (taken from similar subject populations) if MVC force falls outside these limits.     

Adding a selective obturator nerve block to the parasacral sciatic nerve block: an evaluation

Our aim was to objectively evaluate the efficacy of obturator nerve anesthesia after a parasacral block. Patients scheduled for knee surgery had a baseline adductor strength evaluation. After a parasacral block with 30 mL 0.75% ropivacaine, sensory deficit in the sciatic distribution (temperature discrimination) and adductor strength were assessed at 5-min intervals. Patients with an incomplete sensory block (defined as a temperature discrimination score of less than 2 in the 3 cutaneous distributions of the sciatic nerve tested) 30 min after the parasacral block were excluded from the study. Subsequently, a selective obturator block was performed with 7 mL 0.75% ropivacaine and adductor strength was reassessed at 5 min intervals for 15 min. Finally, a femoral block was performed using 10 mL 0.75% ropivacaine. Patient discomfort level during each block was assessed using a visual analog scale (VAS). Thirty-one patients completed the study. Five patients were excluded as a result of inadequate sensory block in the sciatic distribution 30 min after the parasacral block (success rate of 89%). Thirty min after the parasacral block, adductor strength decreased by 11.3% +/- 7% compared with baseline (85 +/- 24 versus 97 +/- 28 mm Hg, P = 0.002). Fifteen min after the obturator nerve block, adductor muscle strength decreased by an additional 69% +/- 7% (16.6 +/- 15 versus 85 +/- 24 mm Hg, P < 0.0001). VAS scores were similar for all blocks (26 +/- 19, 28 +/- 24, and 27 +/- 19 mm for parasacral, obturator, and femoral respectively). Four parasacral blocks were simulated in 2 fresh cadavers using 30 mL of colored latex solution. The spread of the die in relation to the obturator nerve was assessed. Injection of 30 mL colored latex into cadavers resulted in spread of the injectate restricted to the sacral plexus. These findings demonstrate the unreliability of parasacral block to achieve anesthesia of the obturator nerve. A selective obturator block should be considered in the clinical setting when this is desirable.     

Caesarean section in Malawi: preventable factors in maternal and perinatal mortality

Objectives

To examine factors that may influence maternal and perinatal mortality associated with caesarean section in an African country.

Design

A prospective observational study, conducted between January 1998 and June 2000, of 8070 caesarean sections.

Setting

25 district and 2 central hospitals in Malawi.Main outcome measures. Association between hospital type, ward or operative care, training of surgical and anaesthesia personnel, preoperative complications, method of anaesthesia, blood loss and anaesthetic technique on maternal and perinatal mortality.

Results

Questionnaires were returned for 5236 caesarean sections in district and 2834 in central hospitals. 95% were emergencies, 65% for obstructed labour. Pre-operative haemorrhagic shock was present in 7.6% of women, anaemia in 6.2% and ruptured uterus in 4.1%. Previous caesarean section did not appear to predispose to ruptured uterus. There were 85 maternal deaths (1.05% mortality), 65 of which occurred postoperatively on the wards. Maternal mortality was increased with ruptured uterus (adjusted odds ratio 3.9, 95% CI 2.3–6.5), little anaesthetic training (2.3, 1.3 to 4.1) and blood loss requiring transfusion (19.3, 9–41). In mothers without preoperative haemorrhage spinal anaesthesia was associated with lower maternal mortality than general anaesthesia (0.23, 0.1–0.7). Perinatal mortality was 11.2% overall, and was significantly associated with ruptured uterus, halothane and ketamine anaesthesia.

Conclusion

Maternal and perinatal mortality rates among women undergoing caesarean section in Malawi are high. Improving resuscitation in postoperative wards might reduce maternal mortality. Blood loss and pre-operative complications are both strongly associated with mortality. Spinal anaesthesia was associated with good outcome.