Phrenic nerve stimulation in tetraplegia. A new regimen to condition the diaphragm for full-time respiration.

Unipolar phrenic nerve stimulation (diaphragm pacing) has been used for ventilation of patients with C2 tetraplegia. Four-pole sequential nerve stimulation delays muscle fatigue when compared with unipolar stimulation. This may help to achieve more frequently long-term full-time bilateral electroventilation. Four-pole sequential nerve stimulation also offers an opportunity to shorten the conditioning phase of the hypotrophic diaphragm from about 6 to 2 months. The new conditioning regimen was tested successfully in two patients with C2 tetraplegia. The new stimulation method and conditioning regimen remarkably shorten the time after injury during which mechanical ventilation is needed. This will give the patients earlier access to rehabilitation centres for spinal cord injuries and will diminish the work load of the personnel.

Post-operative sore throat: effect of lignocaine jelly and spray with endotracheal intubation.

The effects of laryngeal lignocaine spray and/or lignocaine jelly as lubricants were studied on the incidence of sore throat, hoarseness, or tracheal irritability as evidenced by either a tendency to cough or frank coughing after intubation with a Sensiv tube (Searle Medical Products). Pressure in the medium-volume, low-pressure cuff was controlled and kept below 2.5 kPa (25 cmH2O) during anaesthesia. The side-effects of 94 surgical patients were recorded in a double-blind manner in the recovery room and on the first post-operative day. The lowest number of patients (62%) with side-effects was found in the control group and the greatest (95%) after the combination of lignocaine jelly and spray (P less than 0.05). The number of side-effects after lignocaine jelly alone was 85% and after the spray alone 68%. Women were more prone to have side-effects, especially sore throat and hoarseness, than men (P less than 0.05). Induced hypotension did not increase the incidence of side-effects. Endotracheal cuff pressures were also studied in 114 patients during N2O-O2 anaesthesia and in 54 patients after the replacement of N2O with nitrogen. The minimum occluding pressure required was 1 kPa (10 cmH2O). In 42% of the patients receiving N2O a limiting value of 2.5 kPa (25 cmH2O) was reached during anesthesia in a mean time of 74 min (range 25-180 min). After the replacement of N2O with nitrogen, the cuff pressure decreased from 1.8 kPa (18 cmH2O) to 0.7 kPa (7 cmH2O) over 40 min. It is concluded that lignocaine jelly with the use of a spray significantly increases post-operative side-effects.

Intravenous indomethacin for postoperative pain. A double-blind study of ankle surgery.

Intravenous indomethacin infusion (75 mg/10 h) for relief of pain after ankle surgery was compared with placebo in a double-blind study. Ninety-seven patients were operated on for a malleolar fracture or ruptured ligament of the ankle under single-dose spinal anesthesia. In the indomethacin group, 14 out of 49 patients were free from pain, 4/47 in the control group. Severe pain was experienced by 24/49 in the indomethacin group and by 41/47 in the control group. Supplementary intramuscular oxycodone was needed for 24 patients in the indomethacin group and for 41 control patients. In 1 patient, i.v. indomethacin administration caused serious arterial hypotension necessitating discontinuation of the medication. Intravenous indomethacin reduced the need of opiate for alleviation of postoperative pain, but the possibility of hypersensitivity reaction calls for particular attention.

Electrocardiographic changes during microlaryngoscopy in practolol-pretreated patients under balanced anaesthesia.

Electrocardiographic (ECG) changes were studied in 82 adult patients with a mean age of 49 years undergoing microlaryngoscopy. The patients were pretreated with practolol 0.15 mg/kg i.v. 5 min before induction of anaesthesia with thiopental. Anaesthesia was maintained with nitrous oxide in oxygen, fentanyl and suxamethonium-infusion. ECG changes occurred in 49% of the patients before anaesthesia and procedure. Pre-existing ECG changes increased or new changes occurred in 39% of the patients during intubation and in 38% during the procedure. The most common preanaesthetic ECG changes were flat or negative T-wave (18%), sinus tachycardia (13%), ischaemic S-T segment depression (8.5%) and intraventricular conduction disturbance (8.5%). ECG changes during intubation were sinus tachycardia (16%), ventricular ectopic beats (12%), supraventricular ectopic beats (10%) and ischaemic S-T segment depression (10%). The most common changes during microlaryngoscopy were supraventricular ectopic beats (16%), T-wave flattening or inversion (15%), ischaemic S-T segment depression (11%) and sinus bradycardia (10%). In all patients ECG changes disappeared without any special treatment. Unlike our earlier identical study without practolol pretreatment, neither sinus tachycardia nor junctional rhythm occurred during microlaryngoscopy in the present study. The results suggest that practolol pretreatment before microlaryngoscopy is especially useful when sinus tachycardia and junctional rhythm should be avoided.

Hemodynamic responses to beta-adrenergic blockade with metoprolol and pindolol after coronary artery bypass surgery.

Varying ancillary properties of beta-adrenergic blocking drugs, such as intrinsic sympathomimetic activity or beta 1-selectivity, are known to evoke different hemodynamic effects. These differences may be relevant during hemodynamically unstable conditions. Twenty patients undergoing elective coronary artery bypass surgery were matched in two groups and given either metoprolol tartrate (0.03 mg/kg) or pindolol (0.003 mg/kg) intravenously during recovery from surgery. Heart rate (p less than 0.01) and the rate-pressure product (p less than 0.05) were equally reduced by both beta-blocking drugs. Pindolol also caused a minor decrease in cardiac output (p less than 0.05) and a respective increase in the systemic vascular resistance; all other variables remained stable. It is plausible that in the presence of significant adrenalinemia, which constantly develops after coronary artery surgery, the nonselective pindolol blocks both beta 1-receptors and vascular dilatory beta 2-receptors and thereby increases systemic vascular resistance despite its intrinsic sympathetic activity. Thus, if the use of a beta-blocking agent is considered during the immediate recovery stage following coronary artery bypass surgery, a beta 1-selective drug is more desirable than one with an intrinsic sympathomimetic property.

Comparison of haemodynamic effects of morphine and fentanyl in patients with coronary artery disease.

The haemodynamic effects of morphine (2.5 mg kg-1) and fentanyl (16.7 and 25 micrograms kg-1) were compared in patients undergoing coronary artery bypass surgery. Morphine or fentanyl in combination with pancuronium, nitrous oxide and a small dose of thiopentone produced some deterioration of myocardial performance. Both analgesics failed to block haemodynamic responses to noxious stimulation including tracheal intubation and sternotomy. Heart rate increased following tracheal intubation and systemic vascular resistance increased after sternotomy. However, the larger dose of fentanyl (25 micrograms kg-1) was accompanied by the smallest haemodynamic changes. Supplementary anaesthetic agents were often required to maintain haemodynamic stability during sternotomy. It is suggested here that larger doses of fentanyl, or the addition of other intravenous or inhalation anaesthetics might be employed for patients with severe coronary artery disease and good left ventricular function. On the other hand, in patients with poor left ventricular function, the myocardial depressant properties of thiopentone and nitrous oxide may be detrimental.

Comparison of haemodynamic effects of pethidine and anileridine in anaesthetised patients.

Haemodynamic effects of equianalgesic doses of pethidine (1 mk kg -1) and anileridine (0.25 mg kg -1) were compared in patients with coronary artery disease, after induction of anaesthesia with flunitrazepam - N2O - pancuronium. Contrary to previous findings made in conscious patients, these analgesics produced a moderate circulatory depression. Heart rate, cardiac index and rate-pressure product were decreased by both drugs, and anileridine alone decreased mean arterial pressure. The only statistically significant differences in the haemodynamic changes between the two groups were those in pulmonary capillary wedge pressure and rate pressure product, which were slightly lower after anileridine than after pethidine.

Comparison of haemodynamic effects of metocurine and pancuronium in patients with coronary artery disease.

The haemodynamic effects of large bolus doses of metocurine 0.45 mg kg-1 and pancuronium 0.1 mg kg-1 were compared in patients with coronary artery disease anaesthetized with diazepam, anileridine and nitrous oxide. Hypotension occurred more frequently after metocurine and was a result of a decrease in systemic vascular resistance. After pancuronium there was no increase in arterial pressure or heart rate, but a small increase in cardiac index. The decrease in heart rate after metocurine was the principal cause of the statistically significant difference in cardiac index between the two groups. Contrary to previous findings, metocurine did not attenuate circulatory responses to tracheal intubation. During surgical stimulation, two of the 10 patients of the pancuronium group developed significant ST segment depression and three patients had a rate-pressure product greater than 12 000 mm Hg beat min-1. However, the difference in rate-pressure product between the groups was not statistically significant.