Computerized photo-plethysmography of the finger.

A microcomputer system for studying photo-plethysmography of the finger (PPF) was designed and applied to 50 non-premedicated healthy boys (one to ten years old) undergoing general anaesthesia (halothane in 70% N2O, with mechanical ventilation) for outpatient inguinal hernia repair. The purpose of this study was to assess the accuracy of computerized estimations of the photo-plethysmographic (arterial waves) amplitude and to evaluate whether or not PPF allows discrimination between two different surgical stimuli (skin incision, and manipulation of the spermatic cord). When anaesthesia was stable for at least five minutes (end-tidal halothane = 1.25-1.5%; PETCO2 = 32-38 mmHg; SpO2 > or = 98%; rectal temperature = 36.3-37 degrees C; ambient operating room temperature = 20-21 degrees C), and immediately before the skin incision, computerized estimations of the photo-plethysmographic (arterial waves) amplitudes (PPA) were recorded and saved for later comparison with direct (manual) measurements of the plethysmographic tracing, using an arbitrary scale of 0-255 units. Also, the values of PPA, systolic blood pressure, and pulse rate recorded immediately before the skin incision were later compared with the maximum changes in these same values recorded 30-90 sec after skin incision, and 30-90 sec after manipulation (traction+dissection) of the spermatic cord. Six boys (three to ten years old) stayed quiet enough, during induction of anaesthesia by mask, to allow regression analysis of PPA, systolic blood pressure, and pulse rate (Y) on end-tidal halothane/70% N2O (X). Computerized estimations tended to give a higher reading, by between 0.2 to 0.8 units, than direct measurements.(ABSTRACT TRUNCATED AT 250 WORDS)

Serum gastrin and blood glucose levels during halothane-nitrous oxide anaesthesia and strabismus surgery in children.

The purpose of this study was to determine whether serum gastrin levels are increased by reflexogenic stimuli applied to the extrinsic muscles of the eye. Serum gastrin and blood glucose concentrations were measured in ten normal children aged between 5 and 12 yr during general anaesthesia with halothane and nitrous oxide and during strabismus surgery. Fasting basal concentrations of gastrin (33.6 +/- 14.8 pg.ml-1) and of glucose (4.43 +/- 0.72 mmol.L-1) were in the normal range of values for children. Intravenous atropine (0.01 mg.kg-1), general anaesthesia with halothane in nitrous oxide and oxygen by mask for three minutes, tracheal intubation, extraocular muscle stimulation and surgical stress did not cause any variation in the mean serum gastrin concentration. On the contrary, tracheal intubation and surgical stress increased blood glucose concentrations (P less than 0.05). There was no difference in the serum gastrin levels after extraocular muscle stimulation between children with positive or negative oculocardiac reflexes (44.5 +/- 16.7 pg.ml-1 vs 38 +/- 14.7 pg.ml-1, respectively). The incidence of vomiting predischarge was 60 per cent. Serum gastrin levels did not differ between children who vomited and children who did not (44.3 +/- 18.5 pg.ml-1 vs 47.1 +/- 16.9 pg.ml-1, respectively). Vomiting after strabismus surgery cannot be attributed to high gastrin serum levels. Consequently, it is unlikely that vomiting after strabismus surgery is linked to an "oculogastric reflex" with the vagus nerve as the efferent pathway.

Antiemetic prophylaxis with promethazine or droperidol in paediatric outpatient strabismus surgery.

This randomized, double-blind study evaluated the antiemetic efficacy and the side-effects of promethazine pretreatment (0.5 mg.kg-1 IV + 0.5 mg.kg-1 IM) versus droperidol + placebo pretreatment (droperidol, 0.075 mg.kg-1 IV + physiological saline, 0.02 ml.kg-1 IM). One hundred unpremedicated ASA physical status I children ranging from two to ten years, and undergoing outpatient strabismus surgery were studied. All children received inhalational anaesthesia with halothane, nitrous oxide and oxygen. Neither opioids nor muscle relaxants were used. The incidence of vomiting and/or retching and the incidence of side-effects were determined in the post-anaesthesia recovery room (PARR), in the short-stay surgical unit (SSSU), and after discharge from the hospital (including the journey and the stay at home during the first postoperative day). Promethazine and droperidol were equally effective in reducing the incidence of vomiting before discharge to two and eight per cent respectively. On the contrary, the incidence of vomiting after discharge and overall were significantly less with promethazine (ten and ten per cent) than with droperidol pretreatment (54 and 56 per cent) (P less than 0.0001). Promethazine permitted the time to discharge from the hospital to be reduced to an average of three hours, without increasing the incidence of vomiting postdischarge. Promethazine pretreatment is much less expensive than droperidol pretreatment. The incidence of restlessness was significantly less with droperidol (eight per cent) than with promethazine (36 per cent) (P less than 0.001). Promethazine pretreatment demands the use of an analgesic like acetaminophen in order to reduce the incidence of postoperative pain and restlessness.(ABSTRACT TRUNCATED AT 250 WORDS)

The oculorespiratory reflex revisited.

Continuous measurement of the intratracheal pressure and capnography are very simple and accessible methods for the detection and recording of the oculorespiratory reflex (ORR). Eight healthy children (five to 14 years old) undergoing strabismus surgery under halothane-nitrous oxide anaesthesia with spontaneous ventilation were studied. The ORR was evoked by traction on the extrinsic muscles of the eye (four medial recti and four lateral recti). Slowing of the respiratory rate and/or shallow respiratory movements were observed in each patient. One patient developed apnoea of 20 seconds duration which forced the use of manually controlled ventilation. Intravenous atropine (0.01 mg.kg-1) reduced the incidence of positive OCR (to 37.5 per cent) but did not diminish the incidence of the ORR (100 per cent). Since the ORR may lead to hypercapnia and hypoxaemia, controlled ventilation is recommended for patients undergoing strabismus surgery at least immediately before and during the muscular traction. It is now clear that the ORR may be evoked by traction on the extrinsic muscles of the eye, may produce hypercapnia and hypoxaemia and so, may aggravate the consequences of the OCR.

Succinylcholine, fasciculations and myoglobinaemia.

The prophylactic effectiveness of a small "self-taming" dose of succinylcholine (0.1 mg X kg-1), of d-tubocurarine (0.05 mg X kg-1), and of pancuronium (0.02 mg X kg-1) on succinylcholine-induced fasciculations and myoglobinaemia was studied in 64 healthy children (ages two to nine years), anaesthetized with halothane, nitrous oxide and oxygen. Serum myoglobin was analyzed by radioimmunoassay and taken as a tracer of muscle damage. No correlation was found between the serum levels of myoglobin and the incidence of muscle fasciculations. Self-taming with succinylcholine decreased the incidence of fasciculations (p = 0.001) but did not decrease the succinylcholine-induced myoglobinaemia (p = 0.224). D-tubocurarine (0.05 mg X kg-1) and pancuronium (0.02 mg X kg-1) both significantly reduced the myoglobinaemia and the fasciculations produced by succinylcholine. The pancuronium pretreated group presented less variable values of serum myoglobin which, when compared to the control group, had a more significant p value (p less than 0.001) than for d-tubocurarine pretreated group (p = 0.003). Muscle fasciculations and increased myoglobin levels were observed in children less than four years old who received succinylcholine. The prophylaxis of acute rhabdomyolytic renal failure due to succinylcholine (seven cases reported in the medical literature) is considered.

Acute epiglottitis: an overview.

The authors make use of their experience in the epidemiology, diagnosis, treatment and complications of acute epiglottitis. This study is based on the examination of 212 consecutive cases of infants hospitalized at the "Hôpital Sainte-Justine pour les enfants" (Montreal, Quebec, Canada). These patients were treated following the protocol of a multidisciplinary study that began on January 1, 1974, and continues at the present time. The authors conclude the following: Acute epiglottitis still contributes to sudden death in infants; The overall care of the patient requires a medical transfer with the possibility of an emergency ventilation and intubation; The early diagnosis and treatment are directed by the same protocol that is established by the multidisciplinary work of the anesthesiological, pediatrician, radiologist and ENT specialists.

The oculocardiac reflex in strabismus surgery.

During strabismus surgery on 81 extraocular muscles in 49 children the cardiac response to calibrated traction on each of the muscles operated on was studied through the use of a microdisplacement transducer and the tachometer of a cardiac monitor. There was no significant difference in the frequency of induction of the oculocardiac reflex between the medial rectus and the other muscles or between the two eyes. However, quick traction provoked a reflex in 87% of instances, whereas progressive traction did so in only 51% of instances, a significant difference (p less than 0.05). Thus, because the oculocardiac reflex is frequent during strabismus surgery, cardiac monitoring during the operation and minimal, gentle manipulation of the extraocular muscles are important.

The oculocardiac reflex: a graphic and statistical analysis in infants and children.

A new method for the detection and recording of the oculocardiac reflex (OCR) is described and applied to 49 healthy infants and children (six months to nine years old) undergoing strabismus surgery under halothane anaesthesia with spontaneous ventilation. Eighty-one extraocular muscles were studied. Square wave stimuli (abrupt and sustained tractions) were definitely more reflexogenic than slow slope stimuli (very gradual, progressive and gentle tractions). Vagal escape, as well as fatigue of the OCR, are graphically documented and analysed. In this series, using well-defined and controlled tractions, the medial rectus was not more reflexogenic than the other extraocular muscles. Hypercapnia was an important adjuvant factor of the OCR. Controlled ventilation is recommended. The routine use of intravenous anticholinergic drugs is briefly discussed. Prevention of the OCR, and prophylaxis of cardiac arrhythmias during strabismus surgery, now seem to be placed on a more rational basis.

[Nasotracheal intubation and tracheostomy in acute epiglottitis and laryngotracheal bronchitis]. / L'intubation naso-trachéale et la trachéostomie dans l'épiglottite et la laryngo-trachéo-bronchite aigue.

Acute infectious respiratory distress in children has known different modalities of treatment during these past few years, but controversy remains between tracheostomy and naso-tracheal intubation as ways to cope with the problem. This study, which was undertaken at St. Justine's Hospital in Montreal, reports our complications with the two methods and shows that non-fatal complications are about the same but less serious with naso-tracheal intubation, whereas mortality was 3.2% with tracheostomy and 0% with naso-tracheal intubation. These results entitle us to think that naso-tracheal intubation is the treatment which should be used. This study also reviews different incidence in regards to age, sex, and seasonal prevalence between croup and epiglottitis and also compares the duration of hospital care between the two modalities.

Acute epiglottitis in children: management of 27 consecutive cases with nasotracheal intubation, with special emphasis on anaesthetic considerations.

Twenty-seven consecutive cases of acute epiglottitis in children were treated by nasotracheal intubation during a 25-month period. The duration of intubation averaged 44.2 hours. No mortality or morbidity occurred. Mean hospitalization was 4.5 days. Anaesthetic techniques are discussed. Ketamine is a somewhat controversial choice for these patients as it can enhance excitement, restlessness, and accidental extubation. This study reconfirms the ease of maintaining an assured airway by nasotracheal intubation in cases of acute epiglottitis.