Arterial desaturation in healthy children during transfer to the recovery room

The oxygen saturation in 71 healthy paediatric patients (3.5 months to 16.7 years) was measured by pulse oximetry during transfer from the operating room to the recovery room. These measurements were recorded continuously while the patients breathed room air. Of the patients studied, 28.1 per cent exhibited significant arterial desaturation of less than or equal to 90 per cent. The corresponding PO2 for this saturation level is less than or equal to 58 mmHg. In only 45 per cent of these desaturated patients was the desaturation recognized clinically by the presence of cyanosis. Age, type of anaesthetic, the use or avoidance of narcotics, and the use of controlled or spontaneous respiration had no significant relationship to the incidence of desaturation. Since more than a one quarter of all patients studied desaturated significantly, and since cyanosis can be difficult to detect clinically during the transfer period, the use of supplemental oxygen during transfer should be considered by the anaesthetist at the end of every paediatric general anaesthetic.     

Decreases in arterial oxygen saturation in paediatric outpatients during transfer to the postanaesthetic recovery room

Arterial oxygen saturation was measured by pulse oximetry in two groups of paediatric outpatients breathing room air during transport from the operating room to the postanaesthetic recovery room. In Group I (n = 60) readiness for transfer from OR to PARR was decided clinically. In Group II (n = 50) additional criteria of oxygen saturation (SaOe) greater than or equal to 98 per cent with end-tidal gas N2O less than or equal to 10 per cent and CO2 less than or equal to 45 mmHg were met. A higher incidence of desaturation (SaO2 less than or equal to 90 per cent) occurred in Group I (27 per cent) than in Group II (eight per cent) (P less than 0.05). More children under 2 yr desaturated in Group I (50 per cent) than Group II (17 per cent) (P greater than 0.05 less than 0.10). Twenty-two patients in each group had a recent history of upper respiratory tract infections. In these patients, desaturation was more marked in those in Group I (32 per cent) than in Group II (five per cent) (P less than 0.05). Within each group, the incidence of desaturation during transport was similar in patients with or without a recent URI.     

Hemoglobin desaturation after succinylcholine-induced apnea: a study of the recovery of spontaneous ventilation in healthy volunteers

BACKGROUND: Because of the rapid recovery of neuromuscular function after succinylcholine administration, there is a belief that patients will start breathing sufficiently rapidly to prevent significant oxygen desaturation. The authors tested whether this belief was valid. METHODS: Twelve healthy volunteers aged 18-45 yr participated in the study. After preoxygenation to an end-tidal oxygen concentration greater than 90%, each subject received 5 mg/kg thiopental and 1 mg/kg succinylcholine. Oxygen saturation (SaO2) was measured at both a finger and an ear lobe (beat to beat). During the period of apnea and as they were recovering, the volunteers received continuous verbal reassurance by the investigators. If the SaO2 decreased below 80%, the volunteers received chin lift and, if necessary, assisted ventilation. The length of time the subject was apneic and level of desaturation were related by linear regression analysis. One hour after recovery and again 1 week later, subjects were asked a series of questions regarding their emotional experience. RESULTS: In six volunteers, SaO2 decreased below 95% during apnea; in four, SaO2 decreased below 80%, necessitating chin lift and assisted ventilation in three. Apnea time was significantly longer in volunteers who reached SaO2 less than 80% than in those who did not (7.0+/-0.4 and 4.1+/-0.3 min, respectively), and there was a significant correlation between the length of time the subject was apneic and the magnitude of desaturation. CONCLUSIONS: Spontaneous recovery from succinylcholine-induced apnea may not occur sufficiently quickly to prevent hemoglobin desaturation in subjects whose ventilation is not assisted.     

General anaesthetic management for laser resection of central airway lesions in 85 procedures

The perioperative course of 41 patients undergoing 85 endoscopic laser resections of central airway lesions under general anaesthesia was reviewed. The CO2 laser was used in 60 procedures and the Nd:YAG in 25. Intravenous anaesthesia and Venturi ventilation were utilized for 65 resections; 20 procedures involved predominantly inhalation anaesthesia via the ventilating bronchoscope. Significant intraoperative complications included arterial desaturation (SaO2 less than 90 per cent) in 26 per cent of procedures, and refractory hypertension requiring vasodilator therapy in 19 per cent. Intravenous anaesthesia was associated with a longer duration of recovery room care and a higher incidence of postoperative respiratory complications (delayed extubation, recovery room re-intubation and ventilation, and post-extubation stridor). Inhalation anaesthesia appeared to simplify the intraoperative management and decrease the incidence, duration and severity of immediate postoperative respiratory complications.     

Recovery after anaesthesia with alfentanil or halothane

Seventy-three patients were studied during and after anaesthesia with either alfentanil or halothane for surgical procedures of short duration. The procedures were minor gynaecological or minor urological procedures, involving males and females between the ages of 21 and 86 years. After pre-medication with lorazepam, anaesthesia was induced with methohexitone and continued with nitrous oxide and oxygen, supplemented with halothane (34 patients) or alfentanil (39 patients). Anaesthesia was generally smooth and uncomplicated except that at induction 22 of the patients receiving alfentanil became apnoeic for longer than 30 seconds. Spontaneous respiration resumed without the need for naloxone in any patients. After surgery, recovery of consciousness was significantly more rapid after alfentanil than after halothane (5.6 minutes versus 10.1 minutes). This study demonstrates that alfentanil can be a suitable alternative to conventional general anaesthesia for short cases and may have a useful place when rapid recovery and turnover of cases is important.     

Arterial desaturation in HIV positive patients undergoing sputum induction.

Arterial oxygen saturation (SaO2) was monitored continuously during and immediately after sputum induction in 41 HIV positive patients with respiratory symptoms and in 20 symptomless medical and nursing staff, who acted as control subjects. Arterial oxygen desaturation (defined as SaO2 less than or equal to 92%) occurred during sputum induction and persisted for up to 20 minutes after the end of the procedure in 11 of the 20 patients with Pneumocystis carinii pneumonia and in nine of the 21 patients with other respiratory diagnoses. None of the control subjects showed oxygen desaturation. Neither the severity of chest radiographic abnormalities, the alveolar-arterial oxygen gradient (both measured before sputum induction), nor baseline SaO2 prospectively identified the patients who developed oxygen desaturation. Two patients, one with pneumocystis pneumonia, developed dyspnoea and had a fall in arterial oxygen saturation to 84% within 10 minutes of starting sputum induction. The procedure was abandoned in both patients and in two further patients, who developed severe nausea and reaching but no oxygen desaturation. Sputum induction in HIV positive patients with respiratory symptoms may induce a fall in SaO2 that persists after this procedure. This may be important if other procedures are performed soon after sputum induction.     

OXYGEN DESATURATION AFTER DENTAL ANAESTHESIA

The incidence of oxygen desaturation (<91%) was measuredby pulse oximetry during recovery from outpatient dental anaesthesiain 120 ASA grade I and II children. Alternate cases were givensupplementary oxygen 5 litre min^–1 by mask. Eighteen of60 children (30%) given air and 14 of 60 (23%) given oxygenexhibited desaturation (P>0.05). Desaturation was more likelyto occur if the child was cared for during recovery by locumrather than permanent nursing staff: 22 of 64 (34%) comparedwith 10 of 56 (18%) (P<0.05). It is concluded that significantdesaturation is common after brief dental anaesthesia, thatthe incidence of desaturation is not reduced significantly bysupplementary oxygen and that careful supervision of patientsby experienced recovery room staff is necessary after dentalanaesthesia. Present address: The Hospitals for Sick Children, Great OrmondStreet, London WC1N 3JH.     

Recovery scores do not correlate with postoperative hypoxemia in children

The correlation between the degree of postanesthetic recovery (PAR) in children as measured by a modified Aldrete scoring system and oxygen saturation (SaO2) was studied. Eighty-one ASA PS I unpremedicated infants and children were studied. Oxygen saturation and PAR scores were recorded on arrival in the recovery room, then at 5-minute-intervals. Patients with SaO2 less than 95% were given supplemental oxygen. The proportion of children with SaO2 less than 95% and greater than or equal to 95% was not significantly different among patients with low PAR scores (less than or equal to 6) and those with high scores (7-10) in any age group. Similarly, the magnitude of SaO2 increase after oxygen supplementation did not seem to correlate with increasing wakefulness; i.e., higher PAR scores. It is concluded that children recovering from anesthesia can become hypoxemic in the recovery room. The degree of wakefulness as measured by a PAR score cannot be used to establish an end point for oxygen supplementation. Oxygen supplementation and/or SaO2 monitoring are recommended in all children recovering from anesthesia.     

Removal of the laryngeal mask airway: factors affecting the incidence of post-operative adverse respiratory events in 300 patients

The purpose of this study is to compare the incidence of undesirable respiratory events when the laryngeal mask airway is either removed from patients who are fully awake or from patients who are deeply anaesthetized. Three-hundred patients aged 1.5-81 years were randomly assigned to have their laryngeal mask airway removed either when deeply anaesthetized or after airway reflexes had returned. The occurrence of adverse respiratory events (coughing, oxygen desaturation and airway obstruction) was recorded. Airway obstruction after laryngeal mask airway removal was evident in 20% of patients in the deep anaesthesia group and in 8% of patients in the awake group (P = 0.007). In spite of this finding, oxygen desaturation in children of less than 6 years of age (SaO2 < 96%) occurred most frequently after awake removal (31.3%) compared with deep anaesthesia removal (4.5%) (P = 0.023).     

Digital blocks with and without adrenalin: a randomised-controlled study of capillary blood parameters

This study compared fingertip capillary blood gas parameters before and after digital anaesthesia using lidocaine with and without Adrenalin. Twenty patients who underwent surgery on their fingers under digital ring block anaesthesia were randomly anaesthetised with 2% lidocaine or 2% lidocaine with 1:80,000 Adrenalin. Capillary blood parameters were measured prior to the digital blocks and 15 minutes after the injections. In the plain lidocaine group, PO2 and SaO2 increased significantly after injection (P = 0.025 and 0.017, respectively). In the lidocaine with Adrenalin group, PO2 and SaO2 decreased after the injections. However, this decrease was not statistically significant. Patients in the plain lidocaine group had return of sensation to the finger tip 4.8 (+/-0.6) hours after the operation. This period was 8.1 (+/-0.8) hours for the lidocaine with Adrenalin group.     

Arterial oxygen saturation during general anaesthesia for paediatric dental extractions

Arterial oxygen saturation (SaO2) was measured in 50 healthy children undergoing dental extractions under general anaesthesia. An inhalational anaesthetic technique was employed, with an inspired oxygen concentration of 33%. There were decreases in SaO2 of greater than 5% of the baseline value in 70% of patients, and greater than 10% in 26% of patients. The majority of these decreases were associated with teeth extractions or during placement of dental prop and pack. Non-Caucasian children showed a significantly (p less than 0.05) greater maximum decrease in SaO2 from baseline value compared to Caucasian children. The maximum decreases in SaO2 from baseline value in children anaesthetised by supervised dental students, and in children whose extractions were performed by dental students, were significantly (p less than 0.05) greater than in children whose anaesthetic and surgery were performed by members of staff.     

Time course of change in oxygen saturation and peak expiratory flow in children admitted to hospital with acute asthma.

The time course for recovery of the arterial oxygen saturation (SaO2) in acute childhood asthma is unknown. Serial measurements of SaO2 were made in 47 children during an acute attack of asthma that required admission to hospital. Adequate serial peak expiratory flow (PEF) measurements were possible in 28 children (mean age 8.3 years; group A), but not in the other 19 children (mean age 3.2 years; group B). Measurements of PEF and SaO2 were recorded twice daily before and 30 minutes after they had received salbutamol by nebuliser. Initial SaO2 values (mean (SD) %) were similar in groups A and B at 92.2 (3.5) and 92.4 (2.9). For the children in group A, PEF plateaued 36 hours after admission and SaO2 plateaued 12 hours later. Mean PEF improved after each dose of nebulised salbutamol during the first 36 hours, whereas mean SaO2 increased only after the first dose. SaO2 increased more rapidly in group B. Length of hospital stay was not related to initial SaO2 or PEF values. These data suggest that in children admitted to hospital for acute asthma arterial oxygen saturation is low at admission, recovers more slowly than airway function, reflects bronchodilatation with salbutamol only when SaO2 is low, and recovers more rapidly in younger children than in older children.     

Hypoxemia after general anesthesia in children

Postoperative hypoxemia has been well documented in adults but not in infants and children, although they are potentially more susceptible to airway closure and to disturbances in pulmonary gas exchange. In a prospective study, we measured arterial oxygen saturation (SaO2) with a pulse oximeter in 97 ASA class I infants and children breathing room air before and after general anesthesia for superficial surgical procedures. Mean preoperative SaO2 was 97.6 +/- 0.15% (SEM). On arrival in the recovery room after anesthesia mean SaO2 in room air had decreased significantly (P less than 0.01) to 93.0 +/- 0.49% (range 100-71%), corresponding to calculated arterial oxygen tension (PaO2) of about 66 mm Hg. The second reading, 5-15 min later, also showed a statistically significant (P less than 0.01) decrease in SaO2 (94.1 +/- 0.35%). There was no statistical difference in SaO2 between patients who received inhalation anesthesia alone and those who were given narcotics. There was also no correlation between postoperative reduction in SaO2 and duration of anesthesia or patient age. Of 67 patients who were asleep on arrival in the recovery room, 47 who remained asleep at the second SaO2 reading had an average increase in SaO2 of less than 1%. In contrast, in those patients who awoke, average SaO2 increased more than 4% during a similar time period--a difference that was statistically significant (P less than 0.02).     

The incidence of hypoxia in the immediate postoperative period]

Arterial oxygen saturation (SaO2) was continuously measured using a pulse oximeter in 214 spontaneously breathing adult patients in a recovery room. Hypoxaemia was defined as an SaO2 of 90% or below. The patients were divided into three groups: in group I (n = 83) monitoring was started immediately after arrival in the recovery room, just before oxygen therapy was begun. The patients in group II (n = 106) were observed during and after oxygen therapy. Patients in group III (n = 25), most of whom had regional anaesthesia, were not treated with oxygen in the recovery room. RESULTS. Clinically unexpected hypoxaemia occurred in all three groups: hypoxaemia was observed in 32.6% of patients before oxygen administration (group I). Under oxygen therapy SaO2 was normal in 99.4% of the patients; however, in 30.2% of patients hypoxaemia recurred after oxygen had been discontinued (group II). Hypoxaemic periods were seen in 24% of patients in group III. CONCLUSION. The results indicate the necessity of oxygen administration during transport and in the early postoperative period to all patients. Even during and after regional anaesthesia or brief general anaesthesia, oxygen administration appears to be indicated. Monitoring of SaO2 with a pulse oximeter has become an increasingly standard procedure in modern anaesthesia and should be mandatory.     

Ventilation and gas exchange during sleep in patients with interstitial lung disease.

Ventilation and gas exchange during overnight sleep was studied in a group of seven patients with severe interstitial lung disease (mean vital capacity 50%, mean diffusing capacity 46% predicted), to see whether clinically significant oxygen desaturation occurred. Patients with a history of loud snoring or clinically significant airflow obstruction were excluded. Sleep was fragmented in these patients, but all achieved rapid eye movement (REM) sleep. All patients showed episodes of oxygen desaturation during sleep--mean (SEM) awake arterial oxygen saturation (SaO2) was 92.9% (0.3%) compared with a mean minimum SaO2 during sleep of 83.2% (2.1%) (p less than 0.01). These episodes were, however, transient, and mean SaO2 showed only a slight fall between wakefulness and sleep (non-REM 91.5%, REM 90.4%; NS). Furthermore, SaO2 during non-REM sleep correlated well (p less than 0.001) with SaO2 during wakefulness. Respiratory frequency showed a significant fall between wakefulness and sleep--21.1 (1.8) versus 17.3 (1.5) breaths per minute (p less than 0.02). Our data suggest that nocturnal oxygen treatment need not be considered in patients with interstitial lung disease unless the level of oxygenation while they are awake indicates the need for such treatment.     

Comparison of cardiovascular changes during anaesthesia and recovery from propofol-alfentanil-nitrous oxide and thiopentone-halothane-nitrous oxide anaesthesia in children undergoing otolaryngological surgery

Propofol/alfentanil anaesthesia was compared with thiopentone/halothane anaesthesia in 86 midazolam-atropine premedicated children undergoing minor otolaryngological surgery. The study was randomised, and evaluation of recovery from anaesthesia was double-blind. The children were divided into two age groups: 1–3 years and 4 years and older. Particular attention was paid to EGG changes during anaesthesia and to the rapidity of recovery. One minute after alfentanil 15 μg · kg^-1, the children in the propofol group received propofol 2.0–3.0 mg · kg^-1 followed by propofol infusion 15 mg · kg^-1 · h^-1. In addition, 0.1% suxamethonium 6 mg · kg^-1 · h^-1 was infused during operation. The other children received thiopentone 5–7 mg · kg^-1 followed by halothane (0.5–2%) immediately after endotracheal intubation. Junctional rhythm occurred in 5–35% of the children independent of anaesthesia method, and ventricular ectopic beats were seen in 20% of the older children during halothane anaesthesia. Recovery with respect to times to eye opening or response to verbal contact was significantly faster after propofol/alfentanil anaesthesia than after thiopentone/halothane anaesthesia in the older but not in the younger age group. Furthermore, in the younger age group significantly more crying occurred after propofol/alfentanil than after thiopentone/ halothane anaesthesia. On the basis of this study, thiopentone/halothane anaesthesia is recommended for children aged 1–3 years and propofol/alfentanil anaesthesia for older children undergoing adenoidectomy and/or tonsillectomy.     

Respiratory complications associated with tracheal intubation and extubation

We conducted a prospective survey on the incidence of respiratory complications associated with tracheal intubation and extubation in 1005 patients who underwent elective general anaesthesia over a 4-month period. During induction of anaesthesia, respiratory complications occurred in 46 patients (4.6%; 95% confidence limits (CL): 3.3, 5.9%). The common complications were coughing (1.5%) and difficult ventilation through a facemask (1.4%). Tracheal intubation was difficult in eight patients (0.8%). Complications occurred immediately after tracheal extubation in 127 patients (12.6%; 95% CL: 10.6, 14.7) and in the recovery room in 95 patients (9.5%; 95% CL: 7.6, 11.3%). The common complications immediately after extubation were coughing (6.6%) and oxygen desaturation (SaO2 < 90%) (2.4%), and in the recovery room, airway obstruction (3.8%) and coughing (3.1%). The incidence of complications was significantly higher immediately after tracheal extubation than during induction of anaesthesia (P << 0.001). Even when all incidents of coughing that occurred after tracheal extubation were disregarded as a complication, the overall incidence was still higher immediately after extubation (7.4%) than during induction of anaesthesia (P < 0.01). We conclude that the incidence of respiratory complications associated with tracheal extubation may be higher than that during tracheal intubation.      

A single-blind study of combined pulse oximetry and capnography in children

This single-blind study examined four levels of monitoring in 402 pediatric cases. Patients were randomly assigned to one of four groups: 1) oximeter and capnograph; 2) only oximeter; 3) only capnograph; or 4) neither oximeter nor capnograph data available to the anesthesia team. An anesthesiologist, not involved in patient care, observed all cases and continuously recorded hemoglobin oxygen saturation (Spo2), ECG, expired CO2, and the oximeter plethysmographic output. Mean age, weight, ASA physical status, airway management (mask or endotracheal tube), and anesthetic technique were similar in each group. Two-hundred sixty problems were documented in 153 patients. Fifty-nine events in 43 patients resulted in "major" desaturation (Spo2 less than or equal to 85% for greater than or equal to 30 s). Fifteen "major" capnograph events (esophageal intubation, disconnection, accidental extubation, or obstructed endotracheal tube) were observed in 11 patients; 8 of these also developed varying degrees of desaturation. One-hundred thirty "minor" desaturation events (Spo2 less than or equal to 95% for greater than 60 s) and 79 "minor" desaturation events (hypercarbaria or hypocarbia) were observed. A number of problems fulfilled criteria in multiple categories. Infants less than or equal to 6 months of age had the highest incidence of major desaturation events (18 of 65 [27%]) compared to toddlers 7-24 months of age or children greater than 24 months of age (P less than 0.001). Blinding the oximeter data increased the number of patients (12 vs. 31) experiencing major desaturation events (P = 0.003); blinding the capnograph data altered neither the frequency of desaturation events nor the incidence of major capnograph events.(ABSTRACT TRUNCATED AT 250 WORDS)     

Comparison of spinal anaesthesia with epidural anaesthesia in paediatric surgery

202 children aged 2 months to 17 years, undergoing elective paediatric operations below the umbilicus, were allocated randomly to receive either spinal (SA) or epidural anaesthesia (EA). SA was more efficacious since 8 children of 102 needed supplementation with general anaesthesia, in contrast to EA where 24 children of 100 were supplemented with general anaesthesia and 6 with fentanyl. The haemodynamic stability was maintained during EA, whereas during SA 6 patients were given medication to increase heart rate/blod pressure. EA provided longer pain relief than SA in the recovery room. The incidence of postoperative side effects was similarly low following SA and EA. Complaints after discharge were also similar. General weakness (7% vs 8% after SA and EA, respectively), low back pain (6% vs 6%), headache (7% vs 4%), fever (6% vs 4%) and positional headache (PDPH) (5% vs 3%) were the most frequent side effects. PDPH was only observed following SA in children aged 11 years or older. Following EA, PDPH was also observed in the younger age group after accidental clural puncture. In conclusion, we prefer SA for minor paediatric operations due to its high efficacy.     

Blood glucose and insulin levels during epidural anaesthesia in children receiving dextrose-free solutions

Summary
This study was designed to evaluate the hyperglycaemic response to surgery in two groups of children undergoing minor surgical procedures and receiving dextrose-free solutions during the perioperative period. Twenty-four unpremedicated children of less than eight years of age were randomly assigned to receive either general anaesthesia using halothane, vecuronium and narcotics (GA group, n = 12) or general anaesthesia (halothane, vecuronium) combined with caudal anaesthesia (RA group, n = 12). In both groups blood glucose and insulin concentrations were measured during inhalational induction (T0), at the end of surgery (T1) and 30, 60, 120 min after surgery (T2, T3, T4). A significant hyperglycaemic response to surgery was observed in the GA group, while no changes in blood glucose were observed in the RA group. The maximal blood glucose value was observed 30 min after completion of surgery. Insulin changes followed closely changes in blood glucose values. This study demonstrates that epidural anaesthesia was effective in reducing the hyperglycaemic response to surgery in children scheduled for minor surgical procedures. The lack of increase in blood glucose values under epidural anaesthesia suggests that blood glucose levels should be monitored during the perioperative period, especially after a prolonged fasting time and when oral intake might be delayed.