Risk factors for perioperative adverse respiratory events in children with upper respiratory tract infections.

BACKGROUND: Anesthesia for the child who presents for surgery with an upper respiratory infection (URI) presents a challenge for the anesthesiologist. The Current prospective study was designed to determine the incidence of and risk factors for adverse respiratory events in children with URTs undergoing elective surgical procedures. METHODS: The study population included 1,078 children aged 1 month to 18 yr who presented for an elective surgical procedure. Parents were given a short questionnaire detailing their child's demographics, medical history, and presence of any symptoms of a URT. Data regarding the incidence and severity of perioperative respiratory events were collected prospectively. Adverse respiratory events (any episode of laryngospasm, bronchospasm, breath holding > 15 s, oxygen saturation < 90%, or severe cough) were recorded. In addition, parents were contacted 1 and 7 days after surgery to determine the child's postoperative course. RESULTS: There were no differences between children with active URIs, recent URIs (within 4 weeks), and asymptomatic children with respect to the incidences of laryngospasm and bronchospasm. However, children with active and recent URIs had significantly more episodes of breath holding, major desaturation (oxygen saturation < 90%) events, and a greater incidence of overall adverse respiratory events than children with no URIs. Independent risk factors for adverse respiratory events in children with active URIs included use of an endotracheal tube (< 5 yr of age), history of prematurity, history of reactive airway disease, paternal smoking, surgery involving the airway, the presence of copious secretions, and nasal congestion. Although children with URIs had a greater incidence of adverse respiratory events, none were associated with any long-term adverse sequelae. CONCLUSIONS: The current study identified several risk factors for perioperative adverse respiratory events in children with lulls. Although children with acute and recent URIs are at greater risk for respiratory complications, these results suggest that most of these children can undergo elective procedures without significant increase in adverse anesthetic outcomes.

Oral transmucosal midazolam premedication for preschool children.

PURPOSE: To evaluate the acceptance and effectiveness of 0.2 mg x kg(-1) of oral transmucosal midazolam as a premedicant in infants and preschool children. METHOD: In a randomized, prospective double-blind placebo controlled study, 44 healthy children, between the ages of eight months to six years, presenting for elective surgery were divided in two groups. The medicated group received 0.2 mg x kg(-1) of injectable midazolam mixed with an equal volume of strawberry syrup and the placebo group received plain syrup 0.08 ml x kg(-1). Medications were placed on the anterosuperior aspect of the child's tongue in 3-5 aliquots of 0.2-0.4 ml. A blinded observer assessed the acceptance of the medication by willingness to open the mouth for the next aliquot and the efficacy of the medication was assessed by ease of separation from the parent. RESULTS: Ninety-six percent of the children in the placebo group and 95% in the midazolam group willingly accepted the medication. Separation of children from parents was successful in 95% of the medicated children compared with 59% in the placebo group (P = 0.006). CONCLUSION: Oral midazolam in thick strawberry syrup, administered in small aliquots via the oral transmucosal route was well accepted and proved to be an effective premedicant in infants and preschool children.

Toast and tea before elective surgery? A national survey on current practice.

UNLABELLED: A more tolerant approach to preoperative fasting guidelines for healthy adults undergoing elective surgery was recently recommended by a task force appointed by the American Society of Anesthesiologists. This recommendation liberalizes the intake of clear liquids and specifically allows a light breakfast (e.g., toast and tea or coffee) up to 6 h before elective surgery. We conducted a national survey to determine whether anesthesiologists giving anesthesia in an outpatient setting in the United States were currently following these recommendations, and whether institutional policy reflects these new guidelines. The population consisted of the entire active membership of the Society for Ambulatory Anesthesia, providing an initial sample size of 623 subjects. Most conservatively calculated, we had a response rate of 59.6%. A total of 62% of the respondents said they have an institutional policy in place to allow clear liquids orally 2-3 h before the induction of anesthesia. However, only 35% of the respondents said their institutions had a policy in place allowing a light breakfast 6 h before elective surgery. Nevertheless, only 3% of the responders said they would cancel the operation if a patient actually arrived at the facility after consuming a light breakfast, such as toast and tea 6 h before elective surgery, 32% would delay surgery to later that day, and 65% would proceed without delay. We concluded that most anesthesiologists practicing outpatient anesthesia in the United States have already changed their practice pattern to conform to the recent recommendations of the American Society of Anesthesiologists task force on preoperative fasting time. IMPLICATIONS: Findings of this national survey conducted among active members of the Society for Ambulatory Anesthesia may encourage anesthesiologists throughout the world to take a more liberal attitude toward allowing clear liquids 2-3 h and a light breakfast 6 h before an elective surgery in healthy patients.

A comparison of continuous epidural infusion and intermittent intravenous bolus doses of morphine in children undergoing selective dorsal rhizotomy.

BACKGROUND AND OBJECTIVES: Selective dorsal rhizotomy (SDR) is associated with moderale to severe postoperative pain. Although the efficacy of epidural analgesia in this population has been demonstrated, it has not been compared with conventional intravenous (i.v.) analgesia. This prospective study compared the effects of epidural and i.v. morphine regarding postoperative analgesia, side effects, and outcomes in children following SDR. METHODS: Twenty-seven children were randomized to receive either epidural or i.v. analgesia. Children in the epidural group had a catheter placed by the neurosurgeon and received preservative-free morphine (Duramorph) 30 microg/kg, followed by an infusion of 3 microg/kg/h for 3 days. Children in the i.v. group received morphine 0.05-0.1 mg/kg intraoperatively, followed by 0.02 mg/kg doses postoperatively administered by nurses via a patient-controlled analgesia device. RESULTS: The epidural group experienced lower pain scores (P = .04) and fewer muscle spasms (P < or = .04), and tolerated activity better (P < or = .02) during the early postoperative period than the i.v. group. Side effects were similar between groups, with no respiratory depression in either group. Parents of children in both groups perceived an adequate level of comfort and were very satisfied with the analgesic technique. Additionally, parents believed that their child's postoperative pain was less than anticipated (P < or = .01). CONCLUSIONS: Both techniques provided effective postoperative analgesia with a similar incidence of side effects; however, our findings suggest that continuous infusions of epidural morphine improved overall comfort with lower pain scores, fewer muscle spasms, and improved tolerance of activity during the initial postoperative period.

Use of the laryngeal mask airway in children with upper respiratory tract infections: a comparison with endotracheal intubation.

UNLABELLED: Several studies suggest that placement of an endotracheal tube (ETT) in a child with an upper respiratory infection (URI) increases the risk of complications. However, the development of the laryngeal mask airway (LMA) has provided anesthesiologists with an alternative means of airway management. This study was therefore designed to evaluate the use of the LMA in children with URIs and to compare it with the ETT. The study sample consisted of 82 pediatric patients (3 mo to 16 yr of age) who presented for elective surgery with an URI. Patients with URIs were randomly allocated to receive either an ETT (n = 41) or a LMA (n = 41) and were followed for the appearance and severity of any perioperative complications. The two groups were similar with respect to age, gender, anesthesia and surgery times, number of attempts at tube placement, and presenting URI symptoms. There were no differences between groups in the incidence of cough, breath-holding, excessive secretions, or arrhythmias. Although one patient in the ETT group required a muscle relaxant for laryngospasm, the overall incidence of laryngospasm was similar between the two groups. There was, however, a significantly greater incidence of mild bronchospasm in the ETT group compared with the LMA group (12.2% vs 0%, P < 0.05). The incidence of major arterial oxygen desaturation events (SpO2 <90%) during placement of the airway device was also significantly increased in the ETT group (12.5% vs 0%, P < 0.05). Furthermore, the total number of all episodes of respiratory complications, i.e., breath-holding, laryngospasm, bronchospasm, and major oxygen desaturation, was significantly greater in the ETT group (35 vs 19, P < 0.05). Despite this, all respiratory complications were easily managed, and there were no adverse sequelae. Although the risks associated with anesthetizing a child with an URI remain controversial, results from this study suggest that the LMA offers a suitable alternative to the ETT for use in children with URIs. IMPLICATIONS: This study compares the use of the laryngeal mask airway with the endotracheal tube for airway management in children with upper respiratory infections. Results suggest that if the decision is made to proceed with anesthesia for the child with an upper respiratory infection, then the laryngeal mask airway provides a suitable alternative to the endotracheal tube.

Fasting before and after ambulatory surgery.

During the last decade, questions about the length of time patients were required to fast before elective operations, as well as when they should resume oral fluids after an outpatient operation, became important issues in anesthesia and surgical practice. This review analyzes reasons for the traditional fasting guidelines and presents recent evidence that has caused rethinking in the guidelines. Current recommendations regarding both the presurgical fasting guidelines and fluid intake requirements for discharge after outpatient surgery are outlined.

Should pregnancy testing be routine in adolescent patients prior to surgery?

The reliability of the preoperative history obtained from adolescent patients in ruling out pregnancy was prospectively evaluated. Four hundred forty-four patients who underwent 525 procedures were questioned preoperatively regarding the possibility of pregnancy. Regardless of the history, a urine pregnancy test was ordered in accordance with institutional practice. In 508 cases, patients denied the possibility of pregnancy. Eight patients stated that they might be pregnant, and in six cases the parents responded for the patients and denied the possibility of pregnancy. Seventeen patients were not tested due to patient/parent refusal (n = 9) or inability to void (n = 8). All pregnancy tests were negative except one that was questionably negative. This patient had denied the possibility of pregnancy and had been anesthetized prior to test results. Follow-up revealed that the patient was not pregnant. Our data demonstrate that the preoperative history obtained from adolescent patients at our institution regarding their pregnancy status was in agreement with pregnancy test results. We suggest that a detailed history regarding last menstrual period, contraception, sexual activity, and the possibility of pregnancy be obtained in all postmenarchal patients presenting for surgery. Although in other populations history and pregnancy testing did not agree 100% of the time, for our adolescent population, human chorionic gonadotrophin (HCG) testing appears to be necessary only if indicated by patient history.

Vomiting after outpatient tonsillectomy and adenoidectomy in children: the role of nitrous oxide.

The role of nitrous oxide anesthesia in causing postoperative vomiting (POV) was studied in 60 children undergoing outpatient tonsillectomy and adenoidectomy. In this controlled, randomized, double-blind investigation, anesthesia was induced by inhalation of a volatile anesthetic in both groups. The nonnitrous oxide group received no nitrous oxide, even during induction of anesthesia. Designated nurses in the postanesthesia care unit (PACU) who were blinded to the anesthetic technique evaluated the incidence and the severity of the patient's emetic symptoms, both in the PACU as well as after discharge. Pharmacologic intervention was administered on the basis of evaluation by the nurses. Although a high incidence of POV was noted in both groups, there was no difference in either the incidence or the severity of POV between the group receiving nitrous oxide and the group receiving no nitrous oxide.

Upper respiratory tract infections and general anaesthesia in children. Peri-operative complications and oxygen saturation.

Conflicting reports regarding the hazards of anaesthesia in children presenting for surgery with an upper respiratory tract infection have appeared in the literature. In the present study 130 children undergoing general anaesthesia with face mask for myringotomy and grommet insertion were graded as having either an acute or recent upper respiratory tract infection or were asymptomatic according to predetermined clinical symptoms and signs. The severity of respiratory and related complications were scored during induction, emergence and recovery. The peripheral oxygen saturation was recorded during induction, emergence, transfer to the recovery ward and in the recovery ward itself. There were no significant differences (p greater than 0.05) in the complication scores between the three groups of children. However, the incidence of hypoxaemia (oxygen saturation less than or equal to 93%) was significantly greater during transfer in the acute infection group (p = 0.001) and the recent infection group (p = 0.02), as well as during recovery in the acute group (p = 0.03) compared with asymptomatic children.

Effect of P6 acupressure on postoperative vomiting in children undergoing outpatient strabismus correction.

A prospective, double-blind study was conducted to compare the effect of pressure at the P6 (Neikuan) point with placebo as an antiemetic in children. Sixty-six patients, ages 3-12 yr, undergoing outpatient surgery for correction of strabismus, were allocated randomly to receive either bilateral P6 acupressure or placebo during the perioperative period. The study was designed to detect a 50% difference in the incidence of postoperative vomiting between the two groups, with a 90% power of achieving a statistically significant result at the 5% level (two-tailed). The incidence of postoperative vomiting for the placebo group was 58% before discharge from hospital, 73% at home and 82% in the first 24 h after surgery. The corresponding results for the acupressure group were 58% before discharge, 71% at home and 94% in the first 24 h. These differences were not significant; P6 acupressure did not reduce the incidence of postoperative vomiting in children undergoing strabismus surgery.

Comparison of fentanyl and butorphanol for outpatient anaesthesia.

Equianalgesic doses of butorphanol (40 micrograms X kg-1) and fentanyl (2.0 micrograms X kg-1) were compared as supplements to balanced general anaesthesia for outpatient laparoscopic procedures. Thirty-six adult female patients (ASA physical status I or II) participated in the study. The study drugs (butorphanol or fentanyl) were given just prior to induction of anaesthesia in a double-blind fashion. Following induction with a standard dose of thiopentone and tracheal intubation using succinylcholine, nitrous oxide in oxygen and a succinylcholine infusion were used for maintenance of anaesthesia. Seventeen of the 18 patients in the butorphanol group and 14 of the 18 patients in the fentanyl group showed signs of light anaesthesia and required supplementation with isoflurane. Induction, maintenance and recovery characteristics were not different in the two groups except that the post-intubation arterial pressure and heart rate in the fentanyl group were significantly higher than the base line values and the patients receiving butorphanol were more drowsy and also more pain-free in the postoperative period. The incidence of nausea and vomiting was high in both groups. Overall, butorphanol (40 micrograms X kg-1) used as part of a standard balanced general anaesthetic for a standard outpatient procedure was not superior to fentanyl (2 micrograms X kg-1) used in the same fashion.

Premedication with cimetidine and metoclopramide. Effect on the risk factors of acid aspiration.

A randomised, double-blind, placebo-controlled parallel study was conducted in adult females to evaluate the efficacy and safety of a combination of cimetidine 300 mg orally and metoclopramide 10 or 20 mg intravenously in reducing pre-operative residual gastric volume and raising gastric pH. The effect of preoperative metoclopramide on postoperative nausea and vomiting was also investigated. Oral cimetidine was given approximately 2-2.5 hours before, and intravenous metoclopramide either 15 or 30 minutes prior to induction of anaesthesia. The study showed that placebo-treated patients undergoing outpatient operations have an increased risk of acid aspiration because of high residual gastric volume and low pH and increased risk of serious pulmonary injury should acid aspiration occur. Metoclopramide 10 or 20 mg intravenously prior to induction of anaesthesia was effective in reducing the residual gastric volume significantly, but not in raising pH. The combination of cimetidine and metoclopramide, as well as cimetidine alone, reduced the risk factors of acid aspiration by raising gastric pH and reducing residual volume. No anti-emetic effect of metoclopramide was observed. Higher doses of metoclopramide (20 mg) produced significant side effects (flushing, dizziness, extrapyramidal side effects), but were only marginally more effective than 10 mg doses in reducing residual gastric volume.

Intravenous dezocine for postoperative pain: a double-blind, placebo-controlled comparison with morphine.

Dezocine, a new mixed agonist-antagonist opioid analgesic, and morphine were compared in a double-blind study in 206 patients with postoperative pain. The analgesic efficacy of single intravenous injections of dezocine (2.5, 5.0, and 10.0 mg), morphine (5.0 mg), and placebo was assessed by verbal and visual scales at regular intervals for six hours after administration. All active treatments provided greater pain relief than placebo. Pain relief with dezocine 5 and 10 mg was significantly greater (P less than .05) than with placebo for up to four and five hours, respectively, and with morphine up to one hour. Pain relief scores were significantly higher (P less than .05) with morphine than with placebo at all observations except that of the fifth hour, and higher with dezocine 2.5 mg than with placebo for the first 30 minutes. Doses of 5 and 10 mg of dezocine produced approximately the same peak analgesic effect, with the larger dose having a longer duration of effect. All active treatments produced mild to moderate sedation. Side effects were few and mild or moderate with all of the treatments. The physician's and the patients' evaluations favored dezocine in a dose-dependent order, with morphine 5 mg rated lower than dezocine 5 mg and higher than dezocine 2.5 mg.

Induction and recovery characteristics of isoflurane and halothane anaesthesia for short outpatient operations in children.

Induction and recovery characteristics of isoflurane anaesthesia were compared with halothane anaesthesia during outpatient myringotomy and placement of Sheely ventilation tubes in 101 unpremedicated children. Compared with halothane, isoflurane resulted in prolonged induction times and inferior induction scores due to increased salivation, coughing, breathholding and laryngospasm. However, when modified by halothane induction, isoflurane anaesthesia decreased induction time and improved induction scores. Induction with thiamylal 4 mg/kg did not improve induction scores significantly. Recovery times from halothane plus isoflurane and pure isoflurane anaesthesia were quicker than pure halothane and thiamylal plus isoflurane, although this was not statistically significant. Compared to halothane, anaesthetic induction using isoflurane is associated with an increased incidence of respiratory problems in unpremedicated children.

Double-blind placebo-controlled comparison of dezocine and morphine for post-operative pain relief.

Dezocine, a new mixed agonist-antagonist-type opioid analgesic, was compared in a double-blind trial with placebo and 10 mg of morphine in 190 patients with acute postoperative pain. The medications were given intramuscularly. Dezocine was administered at three dose levels (5, 10, and 15 mg). Pain relief scores, sedation, and side effects were recorded at 15, 30, 60, 120 and 240 min after injection. Significantly higher pain relief scores (p less than 0.05) were reported for the groups receiving dezocine 10 and 15 mg than the placebo group at all observation times, except for dezocine 15 mg at four hours. Morphine produced significantly better pain relief than placebo only between the second and fourth hour after administration. Significantly better pain relief was obtained with dezocine (10 and 15 mg) than with morphine during the first hour. The mean four-hour cumulative pain relief scores (TOTPAR) were significantly (p less than 0.05) higher than placebo for all active treatment groups. Side effects were few with no significant differences between the treatment groups. Seventy-nine per cent of the patients in the dezocine 15 mg group, and 73, 68, 58 and 50 per cent respectively, of the patients in the dezocine 10 mg, dezocine 5 mg, morphine 10 mg and placebo group had a satisfactory clinical response. Significantly (p less than 0.05) more patients in the groups receiving dezocine 10 and 15 mg than in the placebo group had a satisfactory clinical response; the difference was not significant for the dezocine 5 mg and morphine 10 mg groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Physostigmine fails to reverse clinical, psychomotor, or EEG effects of lorazepam.

Physostigmine salicylate (2.0 mg) or 0.9% NaCl (2.0 ml) was administered intravenously in a double-blind fashion to adult volunteers in an attempt to reverse the effects of a 0.05-mg/kg dose of lorazepam given intravenously 30 min earlier. No other medication affecting the central nervous system was given. No differences were observed between the two groups with regard to the frequency of amnesia, psychomotor impairment, or EEG changes during a period of 4 h. The only significant difference in the level of sedation between the two groups was observed 60 min into the study. This difference is attributed to the high incidence of nausea and vomiting that occurred at that time exclusively in one group. Time to complete recovery was the same in both groups. However, physostigmine, not saline, was associated with a high incidence of muscarinic and sympathetic stimulating effects. The results obtained indicate that at the dose used, physostigmine is of no clinical value in treating sedation induced by lorazepam.

Modification by halogenated anaesthetics of chronotropic response during reversal of neuromuscular blockade.

The effect of halothane and enflurane on changes in heart rate during reversal of neuromuscular block was compared in 48 adult patients. Premedication and anaesthetic technique were standardized. Either halothane or enflurane was the primary anaesthetic while pancuronium was used in all patients to achieve muscle relaxation. Ventilation was mechanically controlled and PaCO2 was between 30-40 mmHg. The neuromuscular block was reversed by an intravenous injection of atropine 1.2 mg and neostigmine 2.5 mg, given either separately or simultaneously, in different patient subgroups. Heart rate changes were significantly different between the halothane and enflurane groups. In general, reversal of neuromuscular block was accompanied by less fluctuations in heart rate after enflurane as compared to halothane anaesthesia. Simultaneous injection of atropine and neostigmine modified the tachycardiac response in the halothane sub-group only. Our observations suggest that use of enflurane offers an advantage over halothane in those patients in whom rapid fluctuations in heart rate during reversal of neuromuscular block may be dangerous.

Pneumocephalus after posterior fossa exploration in the sitting position.

Entrainment of air following exploration of posterior cranial fossa in the sitting position was studied in five patients. Intracranial pressure was monitored through a ventriculostomy catheter after closure of the dura. In three patients nitrous oxide was added to the breathing mixture only after the baseline intracranial pressure had stabilised following closure of the dura. A marked rise in intracranial pressure was observed immediately. A rapid decrease in intracranial pressure occurred when nitrous oxide administration was stopped. Two patients were nitrous oxide from the beginning. No change in intracranial pressure was noted. Computerised tomogram on the first postoperative day revealed a significant amount of air in eight cases.