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Biomedical subjects

B Bissonnette

Publications and source records attributed to B Bissonnette.

At least 55 records · Page 3Linked to original sources
PubMed1995

Post-tonsillectomy infiltration with bupivacaine reduces immediate postoperative pain in children.

Pain management after tonsillectomy in children remains a dilemma for the anaesthetist. A previous study demonstrated that the administration of lidocaine 1% topical spray to the peritonsillar fossae before tracheal extubation provided considerable immediate postoperative pain relief in infants and children. However, the pain relief was of short duration. We were hopeful that the use of bupivacaine would offer more prolonged pain relief because of its pharmacological characteristics. Therefore, this study was designed to compare the effects of bupivacaine 0.5% with 1:200,000 epinephrine administered after tonsillectomy either as topical spray or submucosal infiltration on postoperative pain in children. Forty-three patients aged two to ten years were randomized into three groups after tonsillectomy was performed. Group (1) received 0.5 ml.kg-1 normal saline spray; (2) received 2 mg.kg-1 bupivacaine 0.5% with 1:200,000 epinephrine peritonsillar infiltration in a similar volume to Group 1 and; (3) received 2 mg.kg-1 bupivacaine 0.5% with 1:200,000 epinephrine spray to both tonsillar beds. The patients in each group were compared postoperatively with regard to the quality of pain control using the Objective Pain Score, and their analgesic requirements. Peritonsillar infiltration of bupivacaine provided superior immediate postoperative analgesia as reflected by lower recovery room pain scores (P < 0.05) and opioid requirements (P < 0.01). Ward pain scores and analgesic requirements were similar among groups. Peritonsillar infiltration of bupivacaine 0.5% with 1:200,000 epinephrine provides better post-tonsillectomy pain control in the immediate postoperative period than bupivacaine spray or placebo.

Anesthetics, Local↗
PubMed1995

Should the routine use of atropine before succinylcholine in children be reconsidered?

It is common practice to administer atropine before a first dose of succinylcholine in infants and children. However, the administration of succinylcholine without atropine has not been investigated in children. This study was designed to compare cardiovascular changes after the administration of either atropine with succinylcholine or succinylcholine alone. In 41 ASA I or II patients aged from 1 to 12 yr anaesthesia was induced with thiopentone 5 mg.kg-1. Patients were randomly allocated to receive either atropine 20 micrograms.kg-1 and succinylcholine 1.5 mg.kg-1 (n = 20) or succinylcholine 1.5 mg.kg-1 alone (n = 21). Heart rate and rhythm were recorded continuously from two minutes before induction until two minutes after tracheal intubation. Blood pressure was measured non-invasively before and after induction of anaesthesia and both immediately and two minutes after laryngoscopy. One self-limiting episode of bradycardia was recorded during laryngoscopy in a child who received atropine. Heart rate increased in both groups compared with baseline values (108 +/- 25), with a greater increase in patients who had received atropine (150 +/- 13) than in those who had not (128 +/- 18) (P < 0.05). There was no difference in mean arterial pressure or incidence of arrythmias between the two groups. No recorded arrythmias were judged to be clinically important by a cardiologist. The incidence of bradycardia after succinylcholine in the absence of atropine in children aged from 1 to 12 yr appears to be lower than previously estimated. The use of atropine before a single dose of succinylcholine in children deserves to be reconsidered.

Adjuvants, Anesthesia↗
PubMed1994

End-tidal carbon dioxide measurement in infants and children during and after general anaesthesia.

We have examined the reliability of end-tidal carbon dioxide (PetCO2) monitoring as an estimate of arterial carbon dioxide tension (PaCO2) in spontaneously breathing infants and children. Forty patients were studied in the post-anaesthetic care unit; 20 < 12 kg and 20 > or = 12 kg. The PetCO2 was sampled via a 5 cm 16 gauge catheter taped below an external naris and this measurement was compared with the PaCO2 of a sample drawn from an indwelling arterial line. Twenty additional patients were studied during inhalational anaesthesia. The PetCO2 was measured both from the proximal end of the elbow connector and from a 5 cm cannula inserted through the elbow. An arterial blood gas sample was obtained simultaneously. The arterial to end-tidal (Pa-et) differences were compared between the two sites. Patients studied in the post-anaesthetic care unit showed good correlation between PetCO2 and PaCO2 regardless of weight: Pa-etCO2 of -0.6 +/- 3.6 (< 12 kg) and -1.1 +/- 2.8 mmHg (> or = 12 kg). Patients studied during mask anaesthesia showed better correlation between PetCO2 and PaCO2 when PetCO2 was sampled from the cannula: Pa-etCO2 of 3.5 +/- 4.8 mmHg (cannula), 8.6 +/- 4.5 (elbow) (P < 0.05). These results suggest that end-tidal CO2 monitoring is a useful and reliable method for assessing adequacy of ventilation in spontaneously breathing children weighing between 5.2 and 35 kg.

Anesthesia Recovery Period↗
PubMed1994

Awake intubation increases intracranial pressure without affecting cerebral blood flow velocity in infants.

Tracheal intubation is frequently required in neonatal anaesthetic practice. Awake intubation is one method of securing the airway and in certain circumstances, for many anaesthetists, can be preferable to intubation following induction of anaesthesia. Previous studies have inferred that the elevation in anterior fontanelle pressure observed during tracheal intubation in neonates was caused by an increase in cerebral blood flow although it was never measured. In this study, direct methods were used to observe changes in the cerebral circulation. Thirteen neonates, ASA I to III (E), aged from 1 to 34 days of age were studied. Patients were randomized to receive either tracheal intubation awake or following induction of anaesthesia with thiopentone 5 mg.kg-1 and succinylcholine 2 mg.kg-1. Heart rate, systolic arterial blood pressure, anterior fontanelle pressure, cerebral blood flow velocity (using transcranial Doppler sonography) and oxygen saturation were recorded at the following intervals: baseline (not crying), after intravenous atropine 0.02 mg.kg-1, during laryngoscopy, immediately after insertion of the endotracheal tube, one and five minutes later. The use of atropine masked the cardiovascular responses to intubation. Whereas the change in anterior fontanelle pressure from baseline was different between the groups (P < 0.05), the cerebral blood flow velocity variables were not. The rise in anterior fontanelle pressure seen in the awake group may be attributed to a reduction of the venous outflow from the cranium thereby increasing cerebral blood volume and subsequently the intracranial pressure.

Cerebrovascular Circulation↗
PubMed1994

Cerebral arteriovenous malformations in children.

The treatment of cerebral arteriovenous malformations (AVM) or vascular anomalies are challenging neurosurgical procedures for an anaesthetist. Large AVMs are uncommon in children. Only 18% of AVMs become symptomatic before the age of 15 yr. This series reviews the experience at this institution during the period of 1982 to 1992. The symptoms at the time of presentation are varied and include haemorrhage (50%), seizures and hydrocephalus (36%) or congestive cardiac failure (18%). Symptoms of congestive heart failure predominate in the newborn whilst neurological symptoms, such as stroke, seizures or hydrocephalus occur more commonly in infants and older children. Approximately one third of AVMs in childhood present acutely. Radiological investigations, e.g., CT scan, MRI and cerebral angiography are essential to identify the precise location of the lesion. Therapeutic intervention in the acute presentation may involve craniotomy for evacuation of haematoma and treatment of increased intracranial pressure (ICP). Control of seizures and congestive heart failure may take priority and allow time to plan the elective procedures of embolization and surgical excision of the AVM. Operative intervention is hazardous and peroperative complications can be expected in more than 50% of patients. The morbidity and mortality associated with cerebral AVM are high, especially in infants who present in the neonatal period with congestive cardiac failure. The overall mortality in this series was 20%. Children presenting with intracranial arteriovenous malformations require a multidisciplinary approach. The successful management of anaesthesia either for embolization or surgical resection necessitates an understanding of the disciplines of paediatric and neuroanaesthesia. Special care and specific attention to detail may contribute to reduce the high morbidity and mortality encountered in these compromised children.

Adolescent↗
PubMed1994

The most proximal and accurate site for sampling end-tidal CO2 in infants.

The most proximal site to sample end-tidal CO2 with reasonable accuracy in infants during pulmonary ventilation using a Mapleson D circuit remains controversial. The utilisation of high fresh gas flow near the site of gas sampling dilutes the expired gas and causes an underestimation of end-tidal CO2. In this study a laboratory model was used to identify, qualitatively and quantitatively, the most proximal site in the Mapleson D circuit where the measurement of end-tidal CO2 is not influenced by mixing with fresh gas. A fresh gas flow rate of between 2 and 15 L.min-1 with a respiratory rate of 20-30.min-1 and a tidal volume of 30-100 ml.min-1 was evaluated. This experiment was divided into two parts. Firstly, an infant lung model was used to visualize the site of mixing between fresh gas and smoke-labelled exhaled gas. Secondly, fresh gas flow and expired gas flow were controlled and the end-tidal CO2 concentration was measured along the length of the anaesthetic circuit to identify the site of mixing of fresh gas and expired gas during steady-state conditions. Three expired gas flows were studied at six fresh gas flows. In all our studies, the rate of fresh gas flow and expired gas flow influenced the site of mixing and degree of dilution but no mixing was observed distal to the point at which the endotracheal tube connector narrows to the diameter of the endotracheal tube (P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Airway Resistance↗
PubMed1993

Capnometry and the paediatric laryngeal mask airway.

The laryngeal mask airway (LMA), an alternative to tracheal intubation in certain situations, has gained popularity in recent years. Initially designed for use in adults it has now become available in suitable sizes for paediatric anaesthesia. The objectives of this study were to identify the preferred site of sampling the end-tidal carbon dioxide (PETCO2) with the LMA and to determine the accuracy of this recording when compared with arterial CO2 (PaCO2). We studied 30 healthy children, age one to five years and weighing between 10 and 25 kg undergoing minor surgery requiring mask anaesthesia. In each case, after induction of anaesthesia, the LMA was inserted under direct vision to eliminate the possibility of epiglottic airway obstruction. The fresh gas flow was provided by a Jackson Rees modification of an Ayre's T-piece and was determined according to the following formula: 3 x (1000 + (100 x body weight)) LPM. Blood pressure, ECG, O2 saturation, temperature and end-tidal gas concentrations were recorded. The measures of peak PETCO2 were taken at pre-determined distances from the elbow connector down the LMA shaft. During the sampling sequence an arterial blood sample was taken for gas analysis. The PaCO2 was 63.5 +/- 9.3 mmHg (mean +/- SD). At any given sampling site, mean PETCO2 values were less than PaCO2 (P < 0.05). However, in eight patients PETCO2 values measured at the distal site were higher than the PaCO2 (negative P(a-ET)CO2 gradients).(ABSTRACT TRUNCATED AT 250 WORDS)

Anesthesia, Inhalation↗
PubMed1993

Cerebral blood flow velocity patterns during cardiac surgery utilizing profound hypothermia with low-flow cardiopulmonary bypass or circulatory arrest in neonates and infants.

To examine the effects of low-flow cardiopulmonary bypass (CPB) and circulatory arrest (PHCA) on cerebral pressure-flow velocity relationships, we studied 32 patients (< 9 mo of age) undergoing corrective cardiac procedures. Pressure-flow velocity relationships were studied during profound hypothermia (nasopharyngeal temperature < 20 degrees C). Cerebral blood-flow velocity (CBFV) was measured in the middle cerebral artery using transcranial Doppler sonography. The anterior fontanel pressure (AFP) was measured using an intracranial pressure monitor. Cerebral perfusion pressure (CPP) was calculated (mmHg) as mean arterial pressure (MAP) minus AFP. Nasopharyngeal temperature, PaCO2 and haematocrit were controlled during the study period. Alpha-stat acid-base management was employed. The CBFV measurements were made continuously over a range of CPP as pump flow (Q) was decreased to low-flow or to circulatory arrest and again during the subsequent increase in Q and CPP to normal. As Q and CPP were increased after a period of low-flow CPB during which period detectable CBFV was present, the CBFV was greater at any given CPP than prior to the low-flow state (P < 0.05). However, after PHCA a higher CPP (P < 0.05) was necessary to re-establish detectable CBFV and at any given CPP the CBFV was less than prior to PHCA (P < 0.05). Seventeen patients underwent low-flow CPB during which CBFV became non-detectable (7 +/- 1 cm.sec-1). In 12 of these patients the pattern of recovery of CBFV was the same as that observed after low-flow CPB whereas the remaining five (29%) demonstrated a pattern of recovery identical to the ones recorded after PHCA. We conclude that after PHCA a higher CPP is necessary to re-establish and maintain detectable CBFV. Furthermore, during low-flow CPB, patients where CBFV becomes non-detectable and show a pattern of CBFV recovery similar to PHCA, cessation of cerebral perfusion must be considered.

Blood Flow Velocity↗
PubMed1993

Minute ventilation during mask halothane anaesthesia in infants and children.

The pattern of respiration in infants during anaesthesia is not well documented. In this study, minute ventilation (MV) during elective mask halothane anaesthesia (HA) was measured during spontaneous ventilation in infants (Group I) and children (Group II). Airflow was measured with pneumotachography (#0 Fleisch in Group I and #1 Fleisch in Group II). Analogue signals of pressure and flow were recorded on magnetic tape for off-line playback. The flow signal was mathematically integrated to volume. The surgical procedure was divided into three stages: A, B and C representing HA, surgical stimulation and emergence respectively. The pattern of respiration during spontaneous ventilation was described as tidal volume (VTx), respiratory frequency (fx), mean inspiratory flow (VT/TIx), inspiratory duty cycle (TI/TTotx) where the subscript x denoted the stage. Seven infants (2.7 +/- 0.5 mo, 5.8 +/- 0.5 kg) and five children (3.1 +/- 1.1 yr, 15.8 +/- 1.7 kg) were studied. There was no difference in MV between Groups I and II. Halothane anaesthesia in both groups was characterized by rapid shallow breathing: VTA was lower in Group I (2.90 +/- 0.8 ml.kg-1) than in Group II (3.74 +/- 0.40 ml.kg-1) (P < 0.05). Tidal volume was lower during anaesthesia than emergence in both groups (P < 0.05). There was no difference in VT/TIx between groups. The VT/TIA was lower than VT/TIC in Group I (P < 0.05) but not in Group II. There was no intra or intergroup difference in TI/TTot between stages. We suggest that during HA infants have a greater reduction in VT than children, which may predispose infants to hypercarbia during HA.

Anesthesia Recovery Period↗
PubMed1993

What volume can a child normally store in the bladder at a safe pressure?

To determine what volume a child can normally store in the bladder at a safe pressure 923 pediatric urodynamic studies were reviewed, and 69 examinations done on 17 boys and 52 girls were considered normal. Patient ages were recorded and body surface areas were calculated. A continuous intermediate flow water cystometrogram had been performed. Total bladder capacity in milliliters, full resting pressures (cm. water), and the volumes (milliliters) and percentages of the total bladder capacity stored at detrusor pressures of less than 10, 20, 30 and 35 cm. water were measured. We found that 98.1% of the total bladder capacity could be stored at a detrusor pressure of less than 20 cm. water in more than 95% of the children independently of age or body surface area and 99.9% could be stored at a detrusor pressure of less than 30 cm. water. An approximation of the minimal acceptable total bladder capacity for age can be calculated by 16(age) + 70 in ml. According to our results, we proposed criteria for good storage characteristics of the bladder in children.

Body Surface Area↗
PubMed1993

Mild hypothermia does not impair postanesthetic recovery in infants and children.

We tested the hypothesis that mild perioperative hypothermia (e.g., central temperature 34-36 degrees C) does not impair postanesthetic recovery in infants and children. The postoperative course was evaluated in 84 ASA Physical Status 1 or 2 patients, weighing 5-50 kg, who were recovering from peripheral surgery lasting less than 3 h. Postoperative monitoring initiated in the Post Anesthesia Care Unit (PACU) included: 1) rectal (central) temperature; 2) oxyhemoglobin saturation (Spo2) while breathing 21% oxygen; 3) apnea (using impedance pneumography); and 4) duration of recovery determined by an anesthesiologist not involved with the study and unaware of the patients' central temperatures. Data were stratified according to patients' weights and central temperatures on admission to PACU. Recovery was rapid in all patients, with no statistically significant differences in duration of recovery among the groups. Only three patients had Spo2 values less than 90%, and in each case desaturation was observed during only one 15-min epoch and resolved without specific treatment. The lowest observed Spo2 was 82%. These three patients weighed between 10 and 20 kg and had initial temperatures exceeding 36 degrees C. No patient had an apneic episode exceeding 15 s. We conclude that mild hypothermia per se neither impairs respiratory function, nor prolongs postanesthetic recovery in generally infants and children undergoing peripheral surgery.

Anesthesia Recovery Period↗
PubMed1992

Analgesic efficacy and safety of a caudal bupivacaine-fentanyl mixture in children.

The analgesic efficacy and safety of a single caudal injection of a bupivacaine-fentanyl mixture was investigated in this prospective, controlled, triple-blinded study of 34 children, aged 1-11 yr and of ASA physical status I-II undergoing urological surgery. After induction of anaesthesia and before surgery, the children were randomly assigned to receive a caudal injection of 1.0 ml.kg-1 bupivacaine 0.125% with epinephrine 1:400,000 and either fentanyl 1.0 microgram.kg-1 in 1.0 ml of normal saline or 1.0 ml of normal saline. After completion of surgery, patients were assessed in the recovery room for six hours from the time of the caudal injection and for a further 18 hr on the ward. While in the recovery room arterial oxygen saturation and respiratory rate were monitored continuously and recorded hourly together with end-tidal carbon dioxide, pain and sedation scores. Other complications were also recorded. While on the ward, pain and sedation scores, respiratory rate and side effects were recorded every two hours. Postoperative analgesia was provided by intravenous morphine. Analgesic requirements were recorded for the 24-hr study period. Pain and sedation scores did not differ between groups. Respiratory depression or hypoxia did not occur. The incidences of other side effects did not differ. There were no differences in the numbers of patients requiring morphine within eight hours, the time to first morphine administration or the total morphine requirements. We conclude that a single caudal injection of a bupivacaine-fentanyl mixture with epinephrine administered prior to surgery, while safe, offers no advantage over an injection of bupivacaine 0.125% with epinephrine for paediatric urological surgery.

Anesthesia, Caudal↗
PubMed1992

Efficacy, duration, and absorption of a paediatric oral liquid preparation of ranitidine hydrochloride.

The objectives of this study were to assess the clinical efficacy of a new oral ranitidine liquid preparation in reducing gastric acidity and volume, to determine the degree of absorption of the drug, and to determine the duration of drug effect. Eighty preoperative children between the ages of one and six years were enrolled in each of three centres. Each subject was allocated to one of the following groups: Group A - apple juice, 5 ml.kg-1 plus placebo liquid; Group B - apple juice, 5 ml.kg-1 plus ranitidine hydrochloride 2 mg.kg-1; Group C - water, 5 ml and placebo liquid; or Group D - water, 5 ml and ranitidine liquid 2 mg.kg-1. All study agents were administered at least two hours before surgery along with a dye marker, sulfobromophthalein 1 ml (50 mg.ml-1). Following induction of anaesthesia, gastric fluid was aspirated, and analyzed for pH, volume, and sulfobromophthalein content (as an index of the ingested fluids). A serum sample was also drawn and analyzed for ranitidine content by high performance liquid chromatography. Groups B and D had fewer subjects with pH below 2.5 and gastric volume > 0.4 ml.kg-1. The duration of reduced volume and acidity was shown to be greatest from two to four hours after drug administration. Thirty-three percent of subjects receiving oral ranitidine, 2 mg.kg-1 hydrochloride as a single dose demonstrated no measurable effect on gastric pH and volume; 28 of those subjects had adequate ranitidine serum levels.

Absorption↗
PubMed1992

Systolic arterial pressure determination by a new pulse monitor technique.

The Doppler ultrasound (DUS) technique is a widely accepted non-invasive technique to estimate systolic blood pressure (SBP) accurately in paediatric patients. The DUS has a number of limitations. A new pulse monitor, Mr Pulse (MP), operating on the principle of a finger plethysmograph, was developed to offer an alternative technique to estimate SBP. From 104 paired SBP measurements taken in 16 paediatric patients undergoing general anaesthesia, SBP determined by the MP technique correlated closely with that by the standard DUS technique (r2 = 0.98). Analysis of degree of agreement performed indicated that there was good agreement between SBP obtained by the MP and the DUS techniques. The mean +/- standard deviation of differences in paired SBP values between the two measurement techniques was 0.55 +/- 3.59 mmHg. Mr Pulse is as accurate as the DUS technique in estimating SBP and has the advantage of less critical sensor positioning as it is not subject to electrical interference. It has no electrical hazard.

Adolescent↗
PubMed1992

Ineffectiveness of acupuncture and droperidol in preventing vomiting following strabismus repair in children.

The antiemetic effects and side-effects of P6 acupuncture and droperidol pre-treatment were evaluated in a randomized, patient- and observer-blinded study. Ninety unpremedicated children of ASA physical status I or II undergoing outpatient strabismus repair, and aged over one year, were studied. All patients received intravenous thiopentone 5 mg.kg-1, atropine 0.02 mg.kg-1 and succinylcholine 1.5 mg.kg-1, and the trachea was intubated. Patients then received either intravenous droperidol 0.075 mg.kg-1, droperidol plus five minutes' P6 acupuncture, or acupuncture alone. Anaesthesia was maintained with nitrous oxide 66% and halothane 1.5-2.0% in oxygen with spontaneous ventilation. There was no difference in the incidence of vomiting in the droperidol group (17% before discharge from hospital and 41% up to 48 hours after discharge), combined treatment group (17% and 34% respectively) and acupuncture group (27% and 45% respectively). Corresponding figures for the incidence of vomiting before discharge were 17%, 17% and 27% respectively; these values were also not different. The incidence of restlessness was significantly greater in children receiving droperidol (63%) or both treatments (67%) than in those receiving acupuncture alone (30%; P = 0.007). P6 acupuncture and droperidol are equally ineffective in preventing vomiting within 48 hours of paediatric strabismus repair. Droperidol is associated with increased incidence of postoperative restlessness.

Acupuncture Therapy↗