Adrian Reber

Effect of combined mouth closure and chin lift on upper airway dimensions during routine magnetic resonance imaging in pediatric patients sedated with propofol.

BACKGROUND In pediatric patients, obstruction of the upper airway is a common problem during general anesthesia. Chin lift is a commonly used technique to improve upper airway patency. However, little is known about the mechanism underlying this technique. METHODS The authors studied the effect of the chin lift maneuver on airway dimensions in 10 spontaneously breathing children (aged 2-11 yr) sedated with propofol during routine magnetic resonance imaging. The minimal anteroposterior and corresponding transverse diameters of the pharynx were determined at the levels of the soft palate, dorsum of the tongue, and tip of the epiglottis before and during the chin lift maneuver. Additionally, cross-sectional areas were calculated at these sites, including tracheal areas 2 cm below the glottic level. RESULTS Minimal anteroposterior diameter of the pharynx increased significantly during chin lift at all three levels in all patients. The diameters of the soft palate, tongue, and epiglottis increased from 6.7+/-2.8 mm (SD) to 9.9+/-3.6 mm, from 9.6+/-3.6 mm to 16.5+/-3.1 mm, and from 4.6+/-2.5 mm to 13.1+/-2.8 mm, respectively. The corresponding transverse diameter of the pharynx also increased significantly at all three levels in all patients but without significant predominance. The diameters at the levels of the soft palate, tongue, and epiglottis increased from 15.8+/-5.1 mm to 22.8+/-4.5 mm, from 13.5+/-4.9 mm to 18.7+/-5.3 mm, and from 17.2+/-3.9 mm to 21.2+/-3.7 mm, respectively. Cross-sectional pharyngeal areas increased significantly at all levels (soft palate, from 0.88+/-0.58 cm2 to 1.79+/-0.82 cm2; tongue, from 1.15+/-0.45 cm2 to 2.99+/-1.30 cm2; epiglottis, from 1.17+/-0.70 cm2 to 3.04+/-0.99 cm2), including the subglottic level (from 0.44+/-0.15 cm2 to 0.50+/-0.14 cm2). CONCLUSIONS This study shows that all children had a preserved upper airway at all measured sites during propofol sedation. Chin lift caused a widening of the entire pharyngeal airway that was most pronounced between the tip of the epiglottis and the posterior pharyngeal wall. In pediatric patients, chin lift may be used as a standard procedure during propofol sedation.

The effect of chin lift, jaw thrust, and continuous positive airway pressure on the size of the glottic opening and on stridor score in anesthetized, spontaneously breathing children.

Chin lift and jaw thrust are two common maneuvers used to improve the patency of the upper airway during general anesthesia. We investigated the effect of these maneuvers combined with continuous positive airway pressure (CPAP) on the size of glottic opening and on stridor score. Forty children, aged 2–9 yr, premedicated with midazolam and spontaneously breathing end-tidal 1% halothane and equal parts of nitrous oxide and oxygen, were studied. A flexible fiberoptic bronchoscope was placed via mask and one nostril to the level of the junction of the soft palate and oropharynx. Video recordings and simultaneous stridor scores were obtained during six conditions: 1) chin unsupported, 2) manual chin lift, 3) chin lift and CPAP 10 cm H2O, 4) repeat chin unsupported, 5) manual jaw thrust, and 6) jaw thrust and CPAP 10 cm H2O. Videos were analyzed to determine the percentage of glottic opening (POGO) score. POGO score increased (P < 0.05) in Conditions 2, 3, 5, and 6. With increasing POGO score there was a decrease in stridor score (P < 0.05).

Impact of spinal anaesthesia and obesity on maternal respiratory function during elective Caesarean section

Spinal anaesthesia for Caesarean section has gained widespread acceptance. We assessed the impact of spinal anaesthesia and body mass index (BMI) on spirometric performance. In this prospective study, we consecutively assessed 71 consenting parturients receiving spinal anaesthesia with hyperbaric bupivacaine and fentanyl for elective Caesarean section. We performed spirometry during the antepartum visit (baseline), immediately after spinal anaesthesia, 10–20 min, 1 h, 2 h after the operation, and after mobilisation (3 h). Baseline values were within normal ranges. There was a significant decrease in all spirometric parameters after effective spinal anaesthesia that persisted throughout the study period. The decrease in respiratory function was significantly greater in obese (BMI > 30 kg.m−2) than in normal‐weight parturients (BMI < 25 kg.m−2), e.g. median (IQR) vital capacity directly after spinal anaesthesia; −24 (−16 to −31)% vs. −11 (−6 to −16)%, p < 0.001 and recovery was significantly slower. We conclude that both spinal anaesthesia and obesity significantly impair respiratory function in parturients.

The effects of common airway maneuvers on airway pressure and flow in children undergoing adenoidectomies.

Obstruction of the upper airway occurs frequently in anesthetized, spontaneously breathing children, especially in those with adenoidal hyperplasia. To improve airway patency, maneuvers such as chin lift (CL), jaw thrust (JT), and continuous positive airway pressure (CPAP) are often used. In this study, we examined the comparative efficacy of these maneuvers in children scheduled to undergo adenoidectomy. Sixteen children aged 2–9 yr were anesthetized with sevoflurane. During spontaneous breathing, the flows and pressures in the mask (ma), oropharynx (op), and esophagus (es) were measured simultaneously, and maximal pressure differences during inspiration (&Dgr;P) were calculated. After baseline recording, CL and JT maneuvers were performed in random order without and with CPAP (5 cm H2O). The observed &Dgr;Pma − Pes of 12.3 ± 3.4 cm H2O at baseline decreased with all airway maneuvers (P < 0.05). This resulted from decreases of &Dgr;Pma − Pop (P < 0.05) and &Dgr;Pop − Pes (P < 0.05) in all interventions except CL, in which &Dgr;Pma − Pop remained similar. In contrast, significant improvements of minute ventilation and maximal inspiratory peak flow (P > 0.05) were observed only with JT (with and without CPAP). We conclude that CL may improve airway patency and ventilation, whereas JT with or without CPAP was the most effective maneuver to overcome airway obstruction in children with adenoidal hyperplasia.

Opening the upper airway: airway maneuvers in pediatric anesthesia

Maintenance of a patent airway is the most important aspect of the safe administration of anesthesia in children. However, in spontaneously breathing, anesthetized children, upper airway obstruction is a frequent problem (1) and failure to maintain a patent airway can rapidly result in hypoxemia, bradycardia or even cardiac arrest. Upper airway narrowing is most likely to appear in pharyngeal structures (2–4). Since the entire airway is composed of soft tissue and is kept patent during inspiration by the dilating action of the pharyngeal airway muscles, any drug that leads to a reduction of muscle activity can reduce airway patency and thus increase upper airway resistance (5). Children are particularly susceptible to upper airway obstruction because of the smaller dimensions of their airways and the high incidence of tonsillar and/or adenoidal hypertrophy which causes increased resistance to flow (6). During anesthesia and basic life support, positioning of body, head and neck as well as airway maneuvers such as jaw thrust and chin lift are commonly used to improve the patency of an obstructed or partially obstructed upper airway (7, 8). The importance of these maneuvers has been known for a long time; Jacob Heiberg wrote in 1874 that during chloroform anesthesia, noisy, obstructed breathing, particularly during inspiration, can be prevented by pulling the jaw forward (9), while other authors have even earlier advocated opening obstructed airways by pulling the tongue forward (10–12). This review focuses on the mechanisms and efficacy of different, simple methods to open and maintain a patent airway in spontaneously breathing children undergoing anesthesia, which include body, head and neck positioning and airway maneuvers such as mouth opening, chin lift, jaw thrust or the use of continuous positive airway pressure (CPAP).

Impact of spinal anaesthesia on peri-operative lung volumes in obese and morbidly obese female patients

Although obesity predisposes to postoperative pulmonary complications, data on the relationship between body mass index (BMI) and peri‐operative respiratory performance are limited. We prospectively studied the impact of spinal anaesthesia, obesity and vaginal surgery on lung volumes measured by spirometry in 28 patients with BMI 30–40 kg.m−2 and in 13 patients with BMI ≥ 40 kg.m−2. Vital capacity, forced vital capacity, forced expiratory volume in 1 s, mid‐expiratory and peak expiratory flows were measured during the pre‐operative visit (baseline), after effective spinal anaesthesia with premedication, and after the operation at 20 min, 1 h, 2 h, and 3 h (after mobilisation). Spinal anaesthesia and premedication were associated with a significant decrease in spirometric parameters. Spinal anaesthesia and premedication were associated with a significant decrease in spirometric parameters; mean (SD) vital capacities were − 19% (6.4) in patients with BMI 30–40 kg.m−2 and − 33% (9.0) in patients with BMI > 40 kg.m−2. The decrease of lung volumes remained constant for 2 h, whereas 3 h after the operation and after mobilisation, spirometric parameters significantly improved in all patients. This study showed that both spinal anaesthesia and obesity significantly impaired peri‐operative respiratory function.

Comparison of perioperative spirometric data following spinal or general anaesthesia in normal-weight and overweight gynaecological patients

Background:  There is limited data comparing the impact of spinal anaesthesia (SA) and general anaesthesia (GA) on perioperative lung function. Here we assessed the differences of these two anaesthetic techniques on perioperative lung volumes in normal‐weight (BMI < 25) and overweight (BMI 25–30) patients using spirometry.

The impact of postoperative nasal packing on sleep-disordered breathing and nocturnal oxygen saturation in patients with obstructive sleep apnea syndrome.

Nasal septum surgery is frequently performed to establish a functional nasal airway. In these patients obstructive sleep apnea syndrome (OSAS) is frequently present. Although patients with OSAS are at increased risk for hypoxemia, the impact of postoperative nasal packing (PNP) on sleep-disordered breathing and oxygen desaturations in patients with OSAS is unknown. We consecutively investigated 40 patients undergoing endonasal surgery receiving PNP. Fifteen of these patients had previously diagnosed OSAS (Group 2) and 25 did not (Group 1). In the control group, 12 healthy patients underwent elective ear or neck surgery without PNP. During the preoperative and postoperative nights, we continuously measured oronasal flow, thoracoabdominal movements, and oxygen saturation. We calculated the apnea-hypopnea index (AHI) and the oxygen-desaturation index (ODI). Compared with the preoperative values, after the operation, neither AHI nor ODI changed in the control group. In contrast, in Group 1, AHI (from 11 [5–19] to 37 [22–49]) and ODI (from 4 [2–8] to 13 [6–21]) significantly increased (P < 0.05), whereas in Group 2, only AHI significantly increased (from 14 [10–21] to 39 [26–50]); ODI remained similar (13 [8–27] versus 11 [4–37]). Because ODI did not increase in patients with OSAS and PNP who received postoperative oxygen overnight, postoperative intensive care monitoring might not be necessary on a routine basis for all patients with PNP and OSAS.

The effect of epidural analgesia in labour on maternal respiratory function

Lumbar epidural analgesia during labour has gained widespread acceptance. The impact of epidural analgesia based on mixtures of low‐dose local anaesthetic solutions and lipophilic opioids on most clinically relevant obstetric outcomes is minimal. Since the pregnant state per se is associated with important alterations in respiration, we assessed whether a subtle degree of motor blockade brought about by epidural analgesia might compromise respiratory function as assessed by spirometry. Sixty consenting parturients receiving epidural analgesia were consecutively included in this prospective study. We performed spirometry during the antepartum visit and in labour after effective epidural analgesia was established; at both assessments the women were pain‐free. Values were within normal ranges but increased significantly after effective epidural analgesia; median (IQR [range]) increase for vital capacity 7.4 (3.0–13 [−12–27])% (p < 0.001); forced vital capacity 4.4 (1.7–9.8 [−13–26])% (p < 0.001); forced expiratory volume in 1 s 5.5 (1.7–8.6 [−14–28])% (p < 0.001); and peak expiratory flow rate 2.3 (−1.6–5.8 [−18–16])% (p = 0.01)). We conclude that epidural analgesia for labour significantly improved respiratory function.

Airway obstruction due to arytenoid prolapse in a child

In paediatric patients, obstruction of the upper airway is still a common problem during general anaesthesia. This case report documents the susceptibility of arytenoids to prolapse in paediatric patients during halothane anaesthesia. The use of video endoscopy provides an excellent tool for visualizing this type of airway obstruction; and continuous positive airway pressure is an effective treatment for clearing the airway.