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Biomedical subjects

Harald Groeben

Publications and source records attributed to Harald Groeben.

16 recordsLinked to original sources
PubMed2007

Intravenous lidocaine after tracheal intubation mitigates bronchoconstriction in patients with asthma.

BACKGROUND: Although prophylactic IV administration of lidocaine attenuates the response to a variety of inhalation challenges, its effect on airway resistance after endotracheal intubation in patients with asthma is unclear. We tested the hypothesis that IV lidocaine attenuates intubation-evoked bronchoconstriction in patients with asthma. METHODS: Thirty patients with asthma (age 49.1 +/- 15.6 yr [mean +/- sd]) undergoing intubation after standardized anesthetic induction (etomidate 0.3 mg/kg, fentanyl 5 microg/kg, rocuronium 0.6 mg/kg, 50% nitrous oxide) were studied. Airway resistance was measured immediately after intubation and 5, 10, and 15 min later. Five minutes after intubation, either lidocaine (2 mg/kg IV for 5 min, followed by 3 mg x kg(-1) x h(-1) for 10 min) or saline was administered. RESULTS: Airway resistance immediately after intubation averaged 23 +/- 12 cm H2O x s x L(-1). Airway resistance further increased (+38%) after administration of saline, but decreased (-26%, P < 0.004) to less than the initial values after lidocaine. CONCLUSIONS: IV lidocaine given after endotracheal intubation mitigates bronchoconstriction in patients with asthma.

Adult↗
PubMed2006

Epidural anesthesia and pulmonary function.

The epidural administration of local anesthetics can provide anesthesia without the need for respiratory support or mechanical ventilation. Nevertheless, because of the additional effects of epidural anesthesia on motor function and sympathetic innervation, epidural anesthesia does affect lung function. These effects, i.e., a reduction in vital capacity (VC) and forced expiratory volume in 1 s (FEV(1.0)), are negligible under lumbar and low thoracic epidural anesthesia. Going higher up the vertebral column, these effects can increase up to 20% or 30% of baseline. However, compared with postoperative lung function following abdominal or thoracic surgery without epidural anesthesia, these effects are so small that the beneficial effects still lead to an improvement in postoperative lung function. These results can be explained by an improvement in pain therapy and diaphragmatic function, and by early extubation. In chronic obstructive pulmonary disease (COPD) patients, the use of thoracic epidural anesthesia has raised concerns about respiratory insufficiency due to motor blockade, and the risk of bronchial constriction due to sympathetic blockade. However, even in patients with severe asthma, thoracic epidural anesthesia leads to a decrease of about 10% in VC and FEV(1.0) and no increase in bronchial reactivity. Overall, epidural administration of local anesthetics not only provides excellent anesthesia and analgesia but also improves postoperative outcome and reduces postoperative pulmonary complications compared with anesthesia and analgesia without epidural anesthesia.

Anesthesia, Epidural↗
PubMed2006

Posterior retroperitoneoscopic adrenalectomy--results of 560 procedures in 520 patients.

BACKGROUND: The posterior retroperitoneoscopic adrenalectomy is less popular than the laparoscopic transabdominal method. Due to the direct approach to the adrenal glands, however, the posterior retroperitoneal access is easy to use and may offer advantages not available with other endoscopic procedures for adrenalectomy. METHODS: Between July 1994 and March 2006, we performed 560 adrenalectomies (right side: n = 258; left side: n = 302) by the posterior retroperitoneoscopic approach in 520 patients (200 male, 320 female; age, 10 to 83 years). Of the 520 patients, 21 suffered from Cushing's disease, 499 patients had adrenal tumors (157 Conn's adenomas, 120 pheochromocytomas [13 bilateral], 110 Cushing's adenomas [6 bilateral], and 112 other tumors). Tumor size ranged from 0.5 to 10 cm (mean, 2.9 +/- 1.7 cm). The procedures were performed with the patients in the prone position usually with 3 trocars. RESULTS: Mortality was zero. Conversions to open or laparoscopic lateral surgery were necessary in 9 patients (1.7%). Major complications occurred in 1.3% of patients, minor complications in 14.4%. Mean operating time was 67 +/- 40 min and declined significantly (P < .001) from the early procedures (106 +/- 46 min) to the later operations (40 +/- 15 min). CONCLUSIONS: The posterior retroperitoneoscopic adrenalectomy is a safe and fast procedure. In experienced hands, this method represents the ideal approach in adrenal surgery.

Adolescent↗
PubMed2006

Postoperative upper airway obstruction after recovery of the train of four ratio of the adductor pollicis muscle from neuromuscular blockade.

Anesthetics, and even minimal residual neuromuscular blockade, may lead to upper airway obstruction (UAO). In this study we assessed by spirometry in patients with a train-of-four (TOF) ratio >0.9 the incidence of UAO (i.e., the ratio of maximal expiratory flow and maximal inspiratory flow at 50% of vital capacity [MEF50/MIF50] >1) and determined if UAO is induced by neuromuscular blockade (defined by a forced vital capacity [FVC] fade, i.e., a decrease in values of FVC from the first to the second consecutive spirometric maneuver of > or =10%). Patients received propofol and opioids for anesthesia. Spirometry was performed by a series of 3 repetitive spirometric maneuvers: the first before induction (under midazolam premedication), the second after tracheal extubation (TOF ratio: 0.9 or more), and the third 30 min later. Immediately after tracheal extubation and 30 min later, 48 and 6 of 130 patients, respectively, were not able to perform spirometry appropriately because of sedation. The incidence of UAO increased significantly (P < 0.01) from 82 of 130 patients (63%) at preinduction baseline to 70 of 82 patients (85%) after extubation, and subsequently decreased within 30 min to values observed at baseline (80 of 124 patients, 65%). The mean maximal expiratory flow and maximal inspiratory flow at 50% of vital capacity ratio after tracheal extubation was significantly increased from baseline (by 20%; 1.39 +/- 1.01 versus 1.73 +/- 1.02; P < 0.01), and subsequently decreased significantly to values observed at baseline (1.49 +/- 0.93). A statistically significant FVC fade was not present, and a FVC fade of > or =10% was observed in only 2 patients after extubation. Thus, recovery of the TOF ratio to 0.9 predicts with high probability an absence of neuromuscular blocking drug-induced UAO, but outliers, i.e., persistent effects of neuromuscular blockade on upper airway integrity despite recovery of the TOF ratio, may still occur.

Adult↗
PubMed2005

Fade of pulmonary function during residual neuromuscular blockade.

OBJECTIVES: A decrement in evoked muscle force with repetitive nerve stimulation (fade) suggests impaired neuromuscular transmission. We tested the hypothesis that fade of pulmonary function, ie, a decrease in values of FVC with the second spirometric maneuver compared to the first maneuver, occurs during impaired neuromuscular transmission. DESIGN: Prospective study. PARTICIPANTS: Six healthy male volunteers. INTERVENTIONS: A series of three consecutive spirometric maneuvers was performed every 5 min in six awake healthy volunteers before, during, and after partial paralysis evoked by rocuronium (0.01 mg/kg IV plus 2 to 8 microg/kg/min). MEASUREMENTS AND RESULTS: We measured FVC, FEV(1), forced inspiratory volume in 1 s (FIV(1)), peak expiratory flow (PEF), and peak inspiratory flow (PIF) by spirometry, and force of adductor pollicis muscle by mechanomyography (train-of-four [TOF] stimulation). A statistically significant fade (reduction of the second maneuver from the first maneuver) of FVC, FEV(1), FIV(1), PEF, and PIF was observed during neuromuscular blockade. With peak relaxation (TOF ratio, 0.5) fade amounted to medians of 10% (interquartile range [IQR], 9 to 23%), 7% (IQR, 2 to 16%), 31 (IQR, 19 to 47%), 9% (IQR, 3 to 24%), and 30% (IQR, 5 to 43%), respectively. A fade of >or= 10% was always associated with a clinically relevant (>or= 10%) FVC reduction from baseline (ie, FVC before rocuronium administration). However, FVC reduction from baseline was still present in 23% of measurements without a relevant FVC fade. CONCLUSIONS: A clinically relevant fall (fade) in FVC from the first to the second value during or after neuromuscular blockade suggests impaired pulmonary function and may be due to muscle paralysis. For this reason, the first (best) FVC value may overestimate pulmonary function and expose the patient to an unidentified risk.

Adult↗
PubMed2004

Effects of the alpha2-adrenoceptor agonist dexmedetomidine on bronchoconstriction in dogs.

BACKGROUND: Tracheal intubation can elicit reflex bronchoconstriction in patients with asthma or chronic obstructive pulmonary disease, complicating mechanical ventilation and weaning from mechanical support. In vitro studies of human and animal bronchial tissue indicate that alpha2-adrenoceptor stimulation can lead to smooth muscle relaxation and prevention of bronchoconstriction. Dexmedetomidine is a selective alpha2-adrenoceptor agonist approved for sedation in the intensive care unit. Whether dexmedetomidine can affect reflex bronchoconstriction is unknown. METHODS: After the approval of the institutional animal care and use committee, five mongrel dogs were anesthetized with thiopental, endotracheally intubated, and ventilated, and their airways were challenged with histamine. High-resolution computed tomography was used to measure airway luminal areas at baseline and after nebulized histamine. After recovery to baseline, on separate days, dexmedetomidine (0.5 microg/kg) was administered either intravenously or as an aerosol, and the histamine challenge was repeated. RESULTS: At baseline, histamine constricted the airways to 66 +/- 27% (mean +/- SD) (P < 0.0001) and 59 +/- 30% (P < 0.0001) of maximum on the days dexmedetomidine was administered by intravenous and inhalational means, respectively. After recovery, intravenous administration of dexmedetomidine blocked the histamine-induced bronchoconstriction (87 +/- 30.4% of maximum, compared with histamine alone (P < 0.0001), whereas dexmedetomidine administered by inhalation showed no protective effect (45 +/- 30% of maximum; P < 0.0001 compared with histamine alone). CONCLUSION: alpha2-Adrenoceptor stimulation with intravenous dexmedetomidine completely blocked histamine-induced bronchoconstriction in dogs. Therefore, dexmedetomidine might be beneficial to decrease airway reactivity in patients with chronic obstructive pulmonary disease or asthma, particularly during weaning from mechanical ventilation, when neurally mediated airway reflexes may be elicited.

Administration, Inhalation↗
PubMed2004

Corticosteroids and inhaled salbutamol in patients with reversible airway obstruction markedly decrease the incidence of bronchospasm after tracheal intubation.

BACKGROUND: In patients with bronchial hyperreactivity, airway instrumentation can evoke life-threatening bronchospasm. However, the best strategy for the prevention of bronchospasm has not been defined. Therefore, in a randomized, prospective, placebo-controlled study, the authors tested whether prophylaxis with either combined salbutamol-methylprednisolone or salbutamol alone (1) improves lung function and (2) prevents wheezing after intubation. METHODS: Thirty-one patients with partially reversible airway obstruction (airway resistance > 180%, forced expiratory volume in 1 s [FEV1] < 70% of predicted value, and FEV1 increase > 10% after two puffs of salbutamol), who were naive to anti-obstructive treatment, were randomized to receive daily for 5 days either 3 x 2 puffs (0.2 mg) of salbutamol alone (n = 16) or salbutamol combined with methylprednisolone (40 mg/day orally) (n = 15). Lung function was evaluated daily. Another 10 patients received two puffs of salbutamol 10 min before anesthesia. In all patients, wheezing was assessed before and 5 min after tracheal intubation. RESULTS: Within 1 day, both salbutamol and salbutamol-methylprednisolone treatment significantly improved airway resistance (salbutamol, 4.3+/- 2.0 [SD] to 2.9+/-1.3 mmHg x s x l(-1); salbutamol-methylprednisolone, 5.5+/-2.9 to 3.4+/-1.7 mmHg x s x l(-1)) and FEV1 (salbutamol, 1.79+/-0.49 to 2.12+/-0.61 l; salbutamol-methylprednisolone, 1.58+/-0.66 to 2.04+/-1.05 l) to a steady state, with no difference between groups. However, regardless of whether single-dose salbutamol preinduction or prolonged salbutamol treatment was used, most patients (8 of 10 and 7 of 9) experienced wheezing after intubation. In contrast, only one patient receiving additional methylprednisolone experienced wheezing (P = 0.0058). CONCLUSIONS: : Pretreatment with either salbutamol alone or salbutamol combined with methylprednisolone significantly and similarly improves lung function within 1 day. However, only combined salbutamol-methylprednisolone pretreatment decreases the incidence of wheezing after tracheal intubation. Therefore, in patients with bronchial hyperreactivity, preoperative treatment with combined corticosteroids and salbutamol minimizes intubation-evoked bronchoconstriction much more effectively than the inhaled beta2-sympathomimetic salbutamol alone.

Administration, Inhalation↗
PubMed2003

Safety of percutaneous dilational tracheostomy in patients ventilated with high positive end-expiratory pressure (PEEP).

OBJECTIVE: To assess the impact of bronchoscopically guided percutaneous dilational tracheostomy (PDT) on oxygenation in patients with severe respiratory failure ventilated with high positive end-expiratory pressure (PEEP). DESIGN: Prospective clinical study. SETTING: Anaesthesiological ICU, referral centre for acute respiratory distress syndrome (ARDS) therapy, university hospital. PATIENTS: Mechanically ventilated patients with indication for PDT. Two hundred three consecutive PDTs were performed in 198 patients on either high (>10 mbar, n=88) or low (</=10 mbar, n=115) PEEP under bronchoscopic guidance. Arterial blood gas tensions were measured immediately before and 1 and 24 h after PDT. RESULTS: Positive end-expiratory pressure averaged 16.6+/-4 mbar in the high PEEP and 7.6+/-2.2 mbar in the low PEEP group. In the high PEEP group the PaO(2)/FIO(2 )ratio was lower (243+/-90 vs 285+/-78 mmHg) and PaCO(2) higher (45+/-9.4 vs 39+/-7.1 mmHg) when compared to the low PEEP group. Nevertheless, PDT did not significantly decrease oxygenation in either group 1 and 24 h after PDT (PaO(2)/FIO(2): 223+/-83 and 260+/-86 mmHg in the high PEEP group and 280+/-88 and 302+/-82 mmHg in the low PEEP group, respectively). Furthermore, oxygenation did not deteriorate with PDT even in patients with gravely impaired gas exchange (lowest quartile) with a PaO(2)/FIO(2) averaging 130+/-42 mmHg (range 45-192 mmHg) at a PEEP of 17+/-4 mbar. CONCLUSIONS: Bronchoscopically guided PDT in our patients on high PEEP did not jeopardise oxygenation 1 h and 24 h following PDT. Accordingly, high PEEP and hypoxic respiratory failure should not be considered a general contraindication for PDT.

Adult↗
PubMed2003

Accelerometry of adductor pollicis muscle predicts recovery of respiratory function from neuromuscular blockade.

BACKGROUND: Residual paralysis increases the risk of pulmonary complications but is difficult to detect. To test the hypothesis that accelerometry predicts effects of residual paralysis on pulmonary and upper airway function, the authors related tests of pulmonary and pharyngeal function to accelerometry of adductor pollicis muscle in 12 partially paralyzed volunteers. METHODS: Rocuronium (0.01 mg/kg + 2-10 microg x kg-1 x min-1) was administered to maintain train-of-four (TOF) ratios (assessed every 15 s) of approximately 0.5 and 0.8 over a period of more than 5 min. The authors evaluated pharyngeal and facial muscle functions during steady state relaxation and performed spirometric measurements every 5 min until recovery. Upper airway obstruction was defined as a mean ratio of expiratory and inspiratory flow at 50% of vital capacity of greater than 1. The TOF ratio associated with "acceptable" pulmonary recovery (forced vital capacity and forced inspiratory volume in 1 s of > or =90% of baseline) was calculated using a linear regression model. RESULTS: At peak blockade (TOF ratio 0.5 +/- 0.16), forced inspiratory flow was impaired (53 +/- 19%) to a greater degree than forced expiratory flow (75 +/- 20%) with a mean ratio of expiratory and inspiratory flow at 50% of vital capacity of 1.18 +/- 0.6. Upper airway obstruction, observed in 8 of 12 volunteers, paralleled an impaired ability to swallow reported by 10 of 12 volunteers. In contrast, all volunteers except one could sustain a head lift for more than 5 s. The authors calculated that a mean TOF ratio of 0.56 (95% confidence interval, 0.22-0.71) predicts "acceptable" recovery of forced vital capacity, whereas forced inspiratory volume in 1 s was impaired until a TOF ratio of 0.95 (0.82-1.18) was reached. A 100% recovery of TOF ratio predicts an acceptable recovery of forced vital capacity, forced inspiratory volume in 1 s, and mean ratio of expiratory and inspiratory flow at 50% of vital capacity in 93%, 73%, and 88% of measurements (calculated negative predictive values), respectively. CONCLUSION: Impaired inspiratory flow and upper airway obstruction frequently occur during minimal neuromuscular blockade (TOF ratio 0.8), and extubation may put the patient at risk. Although a TOF ratio of unity predicts a high probability of adequate recovery from neuromuscular blockade, respiratory function can still be impaired.

Adult↗
PubMed2003

31-year-old injection drug user with massive skin necrosis and shock.

Massive tissue necrosis and septic shock have recently been reported in a series of injection drug users in Scotland, England and Ireland. We report the first case outside the UK meeting the criteria for this new entity (septic shock without fever in an injection drug user, local and systemic inflammation, rhabdomyolysis and tissue necrosis at the injection site). Following surgical treatment and antibiotic treatment, the patient was cured and is currently well.

Adult↗
PubMed2002

Lung function under high thoracic segmental epidural anesthesia with ropivacaine or bupivacaine in patients with severe obstructive pulmonary disease undergoing breast surgery.

BACKGROUND: Because general anesthesia with tracheal intubation can elicit life-threatening bronchospasm in patients with bronchial hyperreactivity, epidural anesthesia is often preferred. However, segmental high thoracic epidural anesthesia (sTEA) causes pulmonary sympathetic and respiratory motor blockade. Whether it can be safely used for chest wall surgery as a primary anesthetic technique in patients with chronic obstructive pulmonary disease or asthma is unclear. Furthermore, ropivacaine supposedly evokes less motor blockade than bupivacaine and might minimize side effects. To test the feasibility of the technique and the hypotheses that (1) sTEA with ropivacaine or bupivacaine does not change lung function and (2) there is no difference between sTEA with ropivacaine or bupivacaine, the authors studied 20 patients with severe chronic obstructive pulmonary disease (forced expiratory volume in 1 s [FEV1] = 52.1 +/- 17.3% of predicted [mean +/- SD]) or asthma who were undergoing breast surgery. METHODS: In a double-blind, randomized fashion, sTEA was performed with 6.6 +/- 0.5 ml of either ropivacaine, 0.75% (n = 10), or bupivacaine, 0.75% (n = 10). FEV1, vital capacity, FEV1 over vital capacity, spread of analgesia (pin prick), hand and foot skin temperatures, mean arterial pressure, heart rate, and local anesthetic plasma concentrations were measured with patients in the sitting and supine positions before and during sTEA. RESULTS: Segmental high thoracic epidural anesthesia (segmental spread C4-T8 [bupivacaine] and C5-T9 [ropivacaine]) significantly decreased FEV1 from 1.22 +/- 0.54 l (supine) to 1.09 +/- 0.56 l (ropivacaine) and from 1.23 +/- 0.49 l to 1.12 +/- 0.46 l (bupivacaine). In contrast, FEV1 over vital capacity increased from 64.6 +/- 13.5 to 68.2 +/- 14.5% (ropivacaine) and from 62.8 +/- 12.4 to 66.5 +/- 13.6% (bupivacaine). There was no difference between ropivacaine and bupivacaine. Skin temperatures increased significantly, whereas arterial pressure and heart rate significantly decreased indicating widespread sympathetic blockade. All 20 patients tolerated surgery well. CONCLUSIONS: Despite sympathetic blockade, sTEA does not increase airway obstruction and evokes only a small decrease in FEV1 as a sign of mild respiratory motor blockade with no difference between ropivacaine and bupivacaine. Therefore, sTEA can be used in patients with severe chronic obstructive pulmonary disease and asthma undergoing chest wall surgery as an alternative technique to general anesthesia.

Adult↗
PubMed2002

Both local anesthetics and salbutamol pretreatment affect reflex bronchoconstriction in volunteers with asthma undergoing awake fiberoptic intubation.

BACKGROUND: Awake tracheal intubation may evoke reflex bronchoconstriction in asthmatics. Whether this effect is altered by the choice of the local anesthetic used or by pretreatment with a beta2-adrenoceptor agonist is unknown. Therefore, we assessed the effect of awake fiberoptic intubation after lidocaine or dyclonine inhalation with or without pretreatment with salbutamol on lung function in asthmatic volunteers. METHODS: Bronchial hyperreactivity was verified by an inhalational histamine challenge. On four different days in a randomized, double blind fashion the volunteers (n = 10) inhaled either dyclonine or lidocaine with or without salbutamol pretreatment. FEV1 was measured at baseline, following salbutamol or saline inhalation, after lidocaine or dyclonine inhalation, while intubated, and after extubation. Lidocaine and dyclonine plasma concentrations were also measured. STATISTICS: Two-way ANOVA, post hoc tests with Bonferroni correction, results are presented as mean +/- SD. RESULTS: Neither lidocaine nor dyclonine inhalation changed FEV1 significantly from baseline compared with placebo inhalation (4.43 +/- 0.67 l vs. 4.29 +/- 0.72 l, and 4.53 +/- 0.63 l vs. 4.24 +/- 0.80 l, respectively). Salbutamol slightly but significantly increased FEV1 (4.45 +/- 0.76 l vs. 4.71 +/- 0.61 l, P = 0.0034, and 4.48 +/- 0.62 l vs. 4.71 +/- 0.61 l, P = 0.0121, respectively). Following awake intubation FEV1 significantly decreased under lidocaine topical anesthesia (4.29 +/- 0.72 l to 2.86 +/- 0.87 l) but decreased even more under dyclonine anesthesia (4.24 +/- 0.80 l to 2.20 +/- 0.67 l; P < 0.0001). While salbutamol pretreatment significantly attenuated the response to intubation, it did not eliminate the difference between the effects of lidocaine and dyclonine. Only minutes after extubation FEV1 was similar compared with baseline. CONCLUSION: In asthmatics, awake fiberoptic intubation evokes a more than 50% decrease in FEV1 following dyclonine inhalation. Using lidocaine for topical anesthesia the decrease in FEV1 is significantly mitigated (35%) and can be even further attenuated by salbutamol pretreatment. Therefore, combined treatment with lidocaine and salbutamol can be recommended for awake intubation while the use of dyclonine, despite its excellent and longer lasting topical anesthesia, may be contraindicated in patients with bronchial hyperreactivity.

Adult↗
PubMed2001

Complications of bronchoscopically guided percutaneous dilational tracheostomy: beyond the learning curve.

OBJECTIVE: To assess the complication rate of bronchoscopically guided percutaneous dilational tracheostomy (PDT), with tracheal tube suture fixation and no elective tracheostomy tube exchange, after experience had been gained. DESIGN: Prospective clinical study. SETTING: Anaesthesiological ICU with mixed surgical and medical patients in a university hospital. PATIENTS: Hundred thirty-three mechanically ventilated patients (mean age: 54.8 years, range: 13-87 years) with indication for PDT, many with thrombocytopenia and/or coagulation deficits. INTERVENTIONS: Hundred thirty-six consecutive PDTs performed by residents under bronchoscopic guidance with stepwise dilation ( n=114, Ciaglia's conventional system) or conic dilation ( n=22, "Blue Rhino" approach) and supervision of experienced staff anaesthesiologists. Tracheostomy tubes were fixed to the skin with a suture and no routine exchange of tracheostomy tubes was performed. Complications were categorised and the results were also compared to an earlier prospective study. RESULTS: The incidence of tracheostomy tube-related complications (hypoxaemia, cannula misplacement, accidental decannulation, cuff rupture and hernia, or posterior tracheal wall lesion) was low (0.7%) and significantly less (6.2%, p=0.01) than in our earlier study. No patient died of PDT-associated complications. We recorded four (2.9%) clinically relevant bleeding episodes. Insertion of tracheal tubes was easy or only moderately difficult in 86.7%. CONCLUSION: With experience in performing PDT, fixation of the tracheal cannula, and omission of routine change of tracheostomy tubes complication rate of PDT is low.

Adolescent↗
PubMedDate not supplied

The effect of leptin on the ventilatory responseto hyperoxia.

Leptin-deficient mice show a blunted response to hypercapnia explained by central nervous system effects. The impact of leptin on peripheral chemoreceptor function is unclear. Therefore, 9 mutant (ob/ob) and 9 wild-type (+/+) mice were exposed to room air or 100% oxygen and respiratory rate (RR) and tidal volume (Vt) were measured. Subsequently, ob/ob mice received either leptin or vehicle and measurements were repeated. Compared to baseline, for +/+ mice, RR decreased significantly by 9.4% +/- 3.0% (means +/- SD), whereas Vt remained unchanged. Transition from normoxia to hyperoxia did not change RR and Vt in untreated ob/ob mice, whereas after leptin treatment, RR and Vt decreased significantly. Leptin deficiency abolishes the response to hyperoxia, which is restored by leptin replacement. Thus, leptin seems to be influential for a competent peripheral chemoreceptor function.

Animals↗
PubMedDate not supplied

Heritable and pharmacological influences on pauses and apneas in inbred mice during anesthesia and emergence.

Inherited differences in response to hypercapnia are augmented by volatile anesthetics. Therefore, the authors tested the hypotheses that (1) the incidence of pauses and apneas also increase under anesthesia; (2) there is a difference in the incidence between mouse strains; and (3) there is a difference in the incidence of pauses and apneas depending on the volatile agent. The authors assessed respiratory pauses and apneas at rest; during anesthesia with isoflurane, sevoflurane, and desflurane; and at recovery in C3, B6, and F1 mice. The results are compared using analysis of variance (ANOVA) (P<.05). Awake, there was no difference between mouse strains (Bb, 0.3+/-0.7 P min(-1), C3, 0.4+/-0.7 P min(-1) and F1, 0.4+/-0.5 P min(-1)). In contrast, during anesthesia C3 mice showed a significantly higher incidence of pauses and apneas. There was no increase for B6 and F1 mice. There was no difference depending on the volatile agent. These results indicate an inheritance of a susceptibility to pauses and apneas under the influence of volatile anesthetics, albeit independent of the agent used. This response seems to be independent from the inherited response to hypercapnia.

Anesthesia↗