Clinical and economic factors important to anaesthetic choice for day-case surgery.

Clinical and economic factors that are important to consider when selecting anaesthesia for day-case surgery can differ from those for inpatient anaesthesia. Patients undergoing day-case surgery tend to be healthier and have shorter durations of surgery. They expect less anxiety before surgery, amnesia for the surgical experience, a rapid return to normal (normal mentation with minimal pain and nausea) after surgery, and lower expenses. However, the latter 2 expectations can conflict; older generic drugs have lower acquisition costs but often impose longer recovery times. Longer recovery periods can increase costs by prolonging the time to discharge from labour-intensive areas such as the operating suite or the post-anaesthesia recovery unit. The challenge for today's anaesthetist is to use newer drugs judiciously to minimise their expense without compromising the rate or quality of recovery. Several approaches can secure these aims. Most apply the least anaesthetic needed. 'Least anaesthetic' may mean the particular form of anaesthetic (e.g. local infiltration with monitored anaesthesia care versus a general anaesthetic), or may mean the delivery of the smallest effective dose, perhaps guided by anaesthetic monitors such as end-tidal analysers or the bispectral index. For patients requiring general anaesthesia, a combination of several drugs usually secures the closest approach to the ideal. Drug combinations used usually include a short-acting properative anxiolytic (e.g. midazolam), intravenous propofol (a short-acting potent anxiolytic and amnestic agent) for induction of anaesthesia (and sometimes for maintenance) and primary maintenance of anaesthesia with inhaled nitrous oxide combined with a poorly soluble (low solubility produces rapid recovery; the least soluble is desflurane) potent inhaled anaesthetic delivered at a low inflow rate (to minimise cost). Although old, nitrous oxide is inexpensive and has favourable pharmacokinetic and cardiovascular advantages; however, it is limited in its anaesthetic/amnestic potency, and has the capacity to increase nausea. In children, induction of anaesthesia is often accomplished with sevoflurane rather than desflurane; although sevoflurane is modestly more soluble than desflurane, it is non-pungent whereas desflurane is pungent. Moderate- or short-acting opioids (fentanyl is popular) or nonsteroidal anti-inflammatory agents (especially ketorolac), or local anaesthetics are added to secure analgesia during and after surgery. Similarly, when needed, moderate- or short-acting muscle relaxants are selected. Before the end of anaesthesia, an intravenous antiemetic may be given. With this drug combination, patients usually awaken within minutes after anaesthesia and can often move themselves to the vehicle for transport to the recovery unit. These combinations of anaesthetics and techniques minimise use of expensive drugs while expediting recovery (again minimising cost) with minimal or no compromise in the quality of recovery.

A multicenter comparison of maintenance and recovery with sevoflurane or isoflurane for adult ambulatory anesthesia. The Sevoflurane Multicenter Ambulatory Group.

Sevoflurane was compared with isoflurane in 246 adult ASA class I-III patients undergoing ambulatory surgery. After administration of midazolam 1-2 mg and fentanyl 1 microgram/kg, anesthesia was induced with propofol 2 mg/kg and maintained with either sevoflurane or isoflurane in 60% nitrous oxide to maintain arterial blood pressure at +/- 20% of baseline. Fresh gas flows were 10 L/min during induction and 5 L/min during maintenance. Times to eye opening, command response, orientation, and ability to sit without nausea and/or dizziness were significantly faster after sevoflurane. Significantly more sevoflurane patients met Phase 1 of postanesthesia care unit (PACU) Aldrete recovery criteria (> or = 8) at arrival, 95% vs 81%. Also, significantly more sevoflurane patients were able to complete psychomotor recovery tests during the first 60 min postanesthesia. Discharge times were not different. Sevoflurane patients had significantly lower incidences of postoperative somnolence (15% vs 26%) and of nausea both in the PACU (36% vs 51%) and in the 24-h postdischarge period (9% vs 24%). Patient satisfaction was high overall (sevoflurane 97%, isoflurane 93%). We conclude that sevoflurane is a useful inhaled anesthetic for maintenance of ambulatory anesthesia.

Axillary lymphadenectomy for breast cancer without axillary drainage.

OBJECTIVE: To evaluate axillary lymph node dissection done without closed drainage in conjunction with breast conservation cancer surgery. DESIGN: Prospective clinical study. SETTING: Two university hospitals. PATIENTS: Eighty-one women undergoing wide local excision of breast cancer with simultaneous or subsequent axillary lymph node dissection. INTERVENTIONS: No axillary drain was placed following axillary lymphadenectomy. MAIN OUTCOME MEASURES: The development and resorption of axillary seroma fluid as measured by clinical aspiration and serial sonographic examination. RESULTS: Thirty-four (42%) of the 81 women required axillary seroma aspiration even though axillary fluid was present in 92% (22/24) of those studied sonographically. The seromas accumulated over the first 2 weeks following axillary dissection and resorbed over the next 2 weeks, as assessed by both clinical and sonographic examination. The complication rate was 2% (2/81). The surgery was performed safely on an outpatient or short-stay basis in 99% (80/81) of patients. All patients except one were discharged within 23 hours of surgery, and 56 patients were discharged directly after anesthesia. CONCLUSION: Axillary lymph node dissection done in conjunction with breast conservation surgery can be performed in an ambulatory or short-stay setting without axillary drainage. Postoperative seromas will resolve within 1 month, and fewer than half will require aspiration. Lymphadenectomy without drainage reduces morbidity and allows the patient greater personal comfort.

Parental upset associated with participation in induction of anaesthesia in children.

To evaluate the magnitude of parental upset associated with (1) the features of induction most upsetting to parents; (2) the characteristics of parents most likely to become upset; and (3) the accuracy of the anaesthetist's perception of the magnitude of parental upset. The parents (101 mothers and 43 fathers) of 103 children scheduled for elective outpatient surgery requiring general anaesthesia with induction by mask were asked on admission to participate in this study. Parents and children were educated about anaesthesia and surgery according to unit protocols. Immediately after induction of anaesthesia, the parents were asked to complete a demographic information sheet and the Parental Reactions to Anesthesia Induction Questionnaire. Responses were analyzed using descriptive statistics and content analysis. The most upsetting factors for both mothers and fathers in order of significance were: (1) separation from the child after induction of anaesthesia; (2) watching/feeling the child go limp during induction; and (3) seeing the child upset before induction. Characteristics of parents most likely to become upset revealed positive correlations between the amount of upset between mothers and fathers, mothers of an only child, and mothers or fathers who were health care workers (P < 0.05). The anaesthetist's perception of upset correlated with maternal (P < 0.05), but not parental, self-assessment of upset. We conclude that selected factors of parental participation are upsetting for the parents and that recognizing the factors associated with parental upset may enable operating room personnel to minimize these negative consequences.

Pharmacologic patient management in pediatric dentistry: an update.

This paper reviews the issue of sedation in pediatric dentistry in the light of recent controversies and rapidly increasing legal, professional and governmental regulations. Consideration is given to "Guidelines for safe administration of pharmacologic agents in dental practice". The various avenues of drug administration are reviewed with specific comment on recent approaches. Many of the older pharmacologic agents used for pediatric sedation are falling into disfavor. Chloral hydrate, in particular, would seem to be heading toward its demise. The benzodiazepines appear to have a very promising future as sedative agents. When administered and monitored appropriately, they have a wide margin of safety. Consideration is given to research and development into agents that reverse the action of sedative drugs. It is emphasized that contemporary electronic monitoring equipment in no way diminishes the necessity for sound and expert clinical judgment, supplemented by such simple devices as the precordial stethoscope and observation and communication in the form of simple commands.

Anesthesia for pediatric outpatient surgery.

Children are ideal patients for outpatient surgery. Thorough preoperative medical evaluation and selection of appropriate surgical and anesthetic procedures allow most pediatric surgery to be performed safely on an outpatient basis. Psychological preparation, the presence of parents whenever possible, and the appropriate use of premedication minimize the emotional trauma inherent in having anesthesia and surgery. Good anesthetic management consists of selecting anesthetic agents and techniques to promote safety, minimize complications, reduce postoperative nausea, vomiting and pain, and facilitate recovery and discharge. Most importantly, the outpatient setting permits minimal disruption of a child's life and provides an opportunity for the pediatric patient and family to have a positive health-care experience while receiving necessary surgical care.

Cardiovascular actions of nitrous oxide or halothane in hypovolemic swine.

During normovolemia, nitrous oxide causes mild sympathetic stimulation and direct myocardial depression; these effects offset each other, resulting in only minimal cardiovascular changes. To test the hypothesis that during hypovolemia this balance would change and depression predominate, 10 swine were made hypovolemic (30% blood loss) and then were given 70% N2O (0.25 MAC in swine) or an equipotent concentration of halothane, an agent that does not cause sympathetic stimulation. The alternate anesthetic was given to the same hypovolemic swine on another day. Five minutes after induction of anesthesia during hypovolemia, both N2O and halothane caused significant, physiologically important deterioration of compensation for hemorrhage. Halothane decreased systemic vascular resistance (SVR); N2O was more variable in its action, and SVR did not decrease significantly. Both agents caused similar decreases in cardiac output, mean aortic blood pressure, stroke volume, oxygen consumption, and left ventricular minute work, despite increases in plasma epinephrine concentration and plasma renin activity. No differences were found between groups for any of these variables (P greater than 0.05). Plasma norepinephrine concentration increased only in the N2O group and was greater in that group than in the halothane group. The deterioration of cardiovascular compensation for hemorrhage was expressed metabolically by similar decreases in the two groups in partial pressure of oxygen of mixed venous blood and by increases in blood lactate concentration. Thirty minutes after induction of anesthesia, with stable end-tidal anesthetic concentrations, both groups had some cardiovascular, but no metabolic, recovery.(ABSTRACT TRUNCATED AT 250 WORDS)

Haemorrhage decreases the anaesthetic requirement for ketamine and thiopentone in the pig.

The anaesthetic requirements of ketamine and thiopentone were studied in eight pig littermates during normovolaemia and after haemorrhage (30% blood loss). Four animals received ketamine and four thiopentone, and the minimal anaesthetic doses of both drugs were determined. Moderate hypovolaemia decreased the anaesthetic requirements significantly and similarly: thiopentone 33 +/- 5%; ketamine 40 +/- 5% (mean +/- SEM).

Pre-hospital tracheal intubation versus esophageal gastric tube airway use: a prospective study.

A prospective study compared the respiratory effectiveness of the endotracheal tube (ET) with that of the esophageal gastric tube airway (EGTA) for victims of nontraumatic cardiac arrest in the pre-hospital setting. Arterial blood gases were obtained within 3 minutes of hospital arrival, and survival (defined as discharge from the hospital) was determined. During EGTA ventilation, mean pH was 7.12 +/- 0.2, mean P02 was 77 +/- 92 mm Hg, and mean PC02 was 78.2 +/- 42.9 mm Hg; the survival rate was 4.5%. During ET ventilation, mean pH was 7.34 +/- 0.2, mean P02 was 265 +/- 151 mm Hg, mean PC02 was 35 +/- 20.5 mm Hg; the survival rate was 7%. The authors conclude that endotracheal intubation remains the procedure of choice for airway management in the victim of cardiopulmonary arrest.

Recall of surgery for major trauma.

Major traumatic injury frequently causes hemodynamic instability that necessitates reducing the usual dose of anesthetic given for surgery. Nevertheless, a lower dose may be sufficient to provide anesthesia because of conditions present in trauma victims that are known to reduce anesthetic requirement (hypotension, hypothermia, and acute alcohol intoxication). To determine the incidence and patient perception of recall of surgery, 51 patients were interviewed after surgery for major trauma. Patients were assigned to one of two groups. Thirty-seven patients were given an anesthetic for endotracheal intubation and had continuous or almost continuous anesthesia during surgery. Of the four who recalled surgery (11%), two considered this awareness their worst hospital experience. Fourteen other patients, who were more severely injured, were not given an anesthetic for endotracheal intubation and/or for 20 or more consecutive minutes during surgery. Of the six patients in this group who recalled surgery (43%), two considered this awareness their worst hospital experience. No condition known to reduce anesthetic requirement did so reliably enough that recall of surgery did not occur when the anesthetic dose had to be reduced because of major trauma. The authors conclude that the incidence of recall of surgery in victims of major trauma is considerable, and that reducing the dose of anesthetic increases this incidence, despite the presence of conditions known to reduce anesthetic requirement.

Minimum alveolar concentrations (MAC) of halothane and nitrous oxide in swine.

To compare anesthetic effects using a swine model, we needed to know the minimum alveolar concentrations (MAC) of halothane and nitrous oxide that produce anesthesia in the pig. This information does not exist in literature. Furthermore, MAC varies considerably among species: by more than 60% for halothane, and by more than 200% for nitrous oxide. Therefore, using eight young swine, we determined mean (+/- SEM) MAC values for halothane (1.25 +/- 0.04% of one atmosphere) and nitrous oxide (277 +/- 18% of one atmosphere). These values are higher than values reported for other mammals. Factors possibly accounting for this variability include interspecies differences, age, body temperature, increased sympathetic activity, and differences in methodology.

Cardiovascular and metabolic sequelae of inducing anesthesia with ketamine or thiopental in hypovolemic swine.

If further sympathetic stimulation is neither possible nor desirable during moderate hypovolemia, anesthetic agents capable of sympathetic stimulation would not be advantageous for induction of anesthesia during hypovolemia. To test this hypothesis, 21 swine were studied during normovolemia and after 30% of their estimated blood volume was removed. Swine were divided randomly into three equal groups to receive no anesthetic or the minimal anesthetic dose of ketamine (6.65 +/- 0.38 mg/kg, iv) or thiopental (5.77 +/- 0.21 mg/kg, iv). After the initial response to hypovolemia, animals given no drug did not exhibit further changes during the hypovolemic period. Five minutes after induction of anesthesia in the hypovolemic state, ketamine, but not thiopental, caused large increases in plasma epinephrine, norepinephrine, and renin activity. Despite these differences, both anesthetics equally depressed systemic vascular resistance, mean systemic arterial blood pressure, heart rate, and cardiac output. Ketamine, but not thiopental, decreased stroke volume. Neither anesthetic affected oxygen consumption. Both anesthetics caused similar increases in blood lactate concentration. Thirty minutes after induction of anesthesia, plasma epinephrine, norepinephrine, and renin activity remained higher in animals given ketamine than in those given thiopental. Stroke volume, systemic vascular resistance, cardiac output, and oxygen consumption did not differ among groups; however, only the animals given ketamine showed further increase in blood lactate concentration and base-deficit. Thirty minutes after infusion of shed blood, cardiac output and blood lactate concentration were greater in the animals given ketamine than in those given thiopental or no anesthetic. Ninety minutes after infusion of shed blood, no differences existed among groups. The authors conclude that after moderate hemorrhage, further increase in circulating catecholamines is possible but that the levels achieved either exceed the maximal effective concentration at site(s) of action or their effects are overwhelmed by the depressant effects of ketamine.(ABSTRACT TRUNCATED AT 250 WORDS)