Development of age-estimation formula using postmortem oral findings: A pilot study

The goal of this pilot study was to develop an age-estimation formula and assess its effectiveness after evaluating individual intraoral findings. A total of 198 Japanese adults were included, and intraoral findings were collected from the corpses. To analyze the condition of each tooth, 20 items were established for intraoral findings, and seven tooth states were established. Logistic regression analysis was used to estimate the impact of age on each intraoral finding. Sequentially, linear regression was applied to verify the correlation between age and type of tooth, and multiple regression was used to correlate age-dependent factors. The intraoral findings with age dependency were tooth stump, edentulous jaw, attrition, no caries, dental prostheses, partial dentures, and complete dentures. Tooth stump, attrition, and dental prostheses showed positive multicollinearity. Missing tooth, extant tooth, normal teeth, and untreated lost teeth were age-correlated. Multiple regression analysis included age as the response variable and five factors as the explanatory variables in a new age-estimation formula, resulting in ± 10 years for 86.96% of cases (60-69 years old), 76.47% (70-79 years old), and 61.05% of all cases. The multiple correlation was 0.551, and the contribution rate of the multiple regression formula was 0.304. The accuracy of the proposed age-estimation formula was within ± 10 years for 61.05% of all subjects. However, the accuracy of age estimation in subjects aged 60-79 years was excellent (76.47-86.96%), which showed that this age-estimation formula would be effective for estimating the age of middle-aged to older subjects.

Circumstances and factors of sleep-related sudden infancy deaths in Japan

Background

Sudden unexpected death in infancy (SUDI) comprises both natural and unnatural causes of death. However, few epidemiological surveys have investigated SUDI in Japan.

Objective

This retrospective study was conducted to investigate the latest trends of circumstances and risk factors of SUDI cases in which collapse occurred during sleep.

Methods

Forensic pathology sections from eight universities participated in the selection of subjects from 2013 to 2018. Data obtained from the checklist form were analyzed based on information at postmortem.

Results

There were 259 SUDI cases consisting of 145 male infants and 114 female infants with a mean birth weight of 2888 ± 553 and 2750 ± 370 g, respectively. Deaths most frequently occurred among infants at 1 month of age (18%). According to population data as the control, the odds ratio (95% confidence interval) of mother’s age ≤19 years was 11.1 (6.9–17.7) compared with ages 30–39. The odds ratio for the fourth- and later born infants was 5.2 (3.4–7.9) compared with the frequency of first-born infants. The most frequent time of day for discovery was between 7 and 8 o’clock, and the time difference from the last seen alive was a mean of 4.1 h. Co-sleeping was recorded for 61%, and the prone position was found for 40% of cases at discovery. Mother’s smoking habit exhibited an odds ratio of 4.5 (2.9–5.8).

Conclusion

This study confirmed the trends that have been observed for sudden infant death syndrome; particularly, very high odds ratios were evident for teenage mothers and later birth order in comparison with those in other developed countries. Neglect was suspected in some cases of the prolonged time to discovery of unreactive infants. To our knowledge, this is the first report of an extensive survey of SUDI during sleep in Japan.

Bilateral synchronous spindle cell, apocrine and scirrhous carcinoma breast cancer in a case or malignant lymphoma

An unusual case of synchronous bilateral breast cancer occurring during combination chemotherapy and radiation to the outside of the breast for malignant lymphoma is reported. Two histologically rare carcinomas, spindle cell carcinoma and apocrine carcinoma, were observed in this case. A 77-year-old woman, who had been treated for stage IIIA non-Hodgkin's lymphoma, developed bilateral breast tumors. Aspiration biopsy cytology findings of the tumor in the left breast showed several clusters of adenocarcinoma cells and some large atypical spindle shaped cells, which suggested spindle cell carcinoma. The cytologic findings of the right breast tumor were highly suggestive of scirrhous carcinoma. A modified radical mastectomy was performed on both breasts. Pathological examination disclosed two separate cancer lesions in the left breast. The lesion which had been detected before the operation, was a spindle cell carcinoma. Another lesion, detected for the first time by pathological examination, was an apocrine carcinoma. The lesion in the right breast was a scirrhous carcinoma. Since non-invasive foci were detected in these three cancer lesions, each lesion was thought to be a primary cancer. All dissected bilateral axillary lymph nodes showed malignant lymphoma. Immuno-histochemistry of the spindle cell carcinoma revealed positive immunoreactivity for cytokeratin, which suggested the epithelial as well as mesenchymal nature of this tumor. Synchronous existence of malignant lymphoma and three independent breast cancers including spindle cell carcinoma and apocrine carcinoma is very rare.

The alpha2-adrenergic receptor antagonist yohimbine improves endotoxin-induced inhibition of gastrointestinal motility in mice

BACKGROUND

Sepsis inhibits gastrointestinal motility. Although the exact mechanism of this is unclear, lipopolysaccharide is known to activate macrophages in the gastrointestinal wall, which upregulate their expression of inducible nitric oxide synthase (iNOS). This leads to an increased production of nitric oxide, which relaxes the gastrointestinal muscles. We studied endotoxaemic mice to determine whether yohimbine improved delayed gastric emptying and gastrointestinal transit.

METHODS

Male Balb/c mice (n = 49) were randomly allocated to two groups, and either yohimbine 25 microg or saline was injected s.c. Four hours later, mice in each group were further randomly allocated to two groups, and either lipopolysaccharide 100 microg or saline was injected intraperitoneally. Eight hours later, liquid containing fluorescent microbeads was infused into the stomach, and 30 min later, gastric emptying and gastrointestinal transit were measured using flow cytometry. We also studied whether yohimbine given after injection of lipopolysaccharide was effective (n = 22). In another group of mice (n = 32), iNOS in the gastrointestinal tract was measured using western blotting.

RESULTS

Lipopolysaccharide significantly inhibited gastric emptying and gastrointestinal transit. Yohimbine, given before or after lipopolysaccharide, significantly attenuated the inhibitory effects of lipopolysaccharide. Lipopolysaccharide increased the expression of iNOS in the small intestine and yohimbine suppressed the effects of lipopolysaccharide.

CONCLUSIONS

In endotoxaemic mice, yohimbine improved delayed gastric emptying and gastrointestinal transit, possibly by downregulating lipopolysaccharide-induced increased expression of iNOS.

Intrathecal betamethasone pain relief in cancer patients with vertebral metastasis: a pilot study

BACKGROUND

We have reported previously the usefulness of intrathecal betamethasone for pain relief in cancer patients who suffer from intractable pain caused by vertebral metastasis. The mechanism by which betamethasone relieves pain may be related to alterations in cerebrospinal fluid (CSF) concentrations of pro-inflammatory cytokines and prostanoids.

METHODS

Thirteen cancer patients with intractable pain caused by vertebral metastasis received 2-3 mg betamethasone in the lumbar subarachnoid space. CSF concentrations of tumor necrosis factor-alpha (TNF-alpha), interleukin-1beta (IL-1beta), IL-6, IL-8 and prostaglandin E(2) (PGE(2)) were measured with an enzyme-linked immunosorbent assay (ELISA) and a chemiluminescence enzyme immunoassay. Pain was measured using a numerical pain score (range, 0-10; 0, no pain; 10, worst pain imaginable).

RESULTS

Intrathecal betamethasone was associated with a significant decrease in the pain score in six patients. In these cases, the pain score decreased from 6.7 +/- 0.5 (mean +/- standard error of the mean) to 3.3 +/- 0.3 (P < 0.05), and the CSF concentrations of IL-8 and PGE(2) decreased significantly compared with pre-treatment levels (IL-8, 183.3 +/- 21.2 to 116.5 +/- 10.6 pg/ml; PGE(2), 43.8 +/- 10.3 to 14.7 +/- 3.0 pg/ml). There were no significant changes in the CSF concentrations of cytokines and PGE(2) in the remaining seven patients.

CONCLUSION

Pain relief with intrathecal betamethasone is related to decreases in the CSF concentration of IL-8 and PGE(2).

Intrathecal betamethasone for cancer pain in the lower half of the body: a study of its analgesic efficacy and safety

BACKGROUND

Sufficient analgesia for cancer pain is sometimes difficult to achieve with conventional treatments. We aimed at investigating the analgesic efficacy and safety of intrathecal betamethasone in patients with uncontrollable cancer pain.

METHODS

Betamethasone 1 mg mixed with saline was injected into the lumbar intrathecal space once a week in 10 patients with persistent cancer pain in the lower half of the body. During the 4-week study period, the analgesic efficacy and adverse effects related to intrathecal betamethasone were observed.

RESULTS

Long-lasting analgesia (mean numerical pain score < or = 5) for 7 days, after immediate analgesia within 10 min, was obtained without the need to increase the morphine dose in 5 of 10 patients. In almost all of the patients, not only pain, but also uncomfortable symptoms were improved. Adverse effects related to neurotoxicity of intrathecal betamethasone, such as sensory and motor dysfunctions, were not observed in any patients.

CONCLUSION

When conventional cancer pain treatments are not successful, intrathecal betamethasone may be useful, as it probably induces long-lasting analgesia without adverse effects and improves activities of daily living, especially in patients with vertebral bone metastases.

Inducible nitric oxide synthase and tumor necrosis factor-alpha in delayed gastric emptying and gastrointestinal transit induced by lipopolysaccharide in mice

Gastrointestinal motility disturbances during endotoxemia are probably caused by lipopolysaccharide (LPS)-induced factors: candidates include nitric oxide (NO), tumor necrosis factor-alpha (TNF-alpha), interleukin-1ss, and interleukin-6. Flow cytometry was used to determine the effects of LPS and these factors on gastric emptying (evaluated indirectly by determining percent gastric retention; %GR) and gastrointestinal transit (GIT) in male BALB/c mice (23-28 g). NO (300 microg/mouse, N = 8) and TNF-alpha (2 microg/mouse, N = 7) increased (P < 0.01) GR and delayed GIT, mimicking the effect of LPS (50 microg/mouse). During early endotoxemia (1.5 h after LPS), inhibition of inducible NO synthase (iNOS) by a selective inhibitor, 1400 W (150 microg/mouse, N = 11), but not antibody neutralization of TNF-alpha (200 microg/mouse, N = 11), reversed the increase of GR (%GR 78.8 +/- 3.3 vs 47.2 +/- 7.5%) and the delay of GIT (geometric center 3.7 +/- 0.4 vs 5.6 +/- 0.2). During late endotoxemia (8 h after LPS), both iNOS inhibition (N = 9) and TNF-alpha neutralization (N = 9) reversed the increase of GR (%GR 33.7 +/- 2.0 vs 19.1 +/- 2.6% (1400 W) and 20.1 +/- 2.0% (anti-TNF-alpha)), but only TNF-alpha neutralization reversed the delay of GIT (geometric center 3.9 +/- 0.4 vs 5.9 +/- 0.2). These findings suggest that iNOS, but not TNF-alpha, is associated with delayed gastric emptying and GIT during early endotoxemia and that during late endotoxemia, both factors are associated with delayed gastric emptying, but only TNF-alpha is associated with delayed GIT.

Propofol acts at the sigma-1 receptor and inhibits pentazocine-induced c-Fos expression in the mouse posterior cingulate and retrosplenial cortices

BACKGROUND

The sigma-1 receptor is functionally linked with psychotomimetic effects of various drugs. A sigma-1 receptor agonist enhances bradykinin-induced intracellular Ca(2+) concentration ([Ca(2+)]i) increase and induces c-Fos expression in a part of the brain. The aim of this study was to investigate the effects of several intravenous anaesthetics on the sigma-1 receptor.

METHODS

First, using Wistar rat brains, (+)[(3)H]SKF-10,047, a selective sigma-1 receptor agonist was displaced by propofol, dexmedetomidine, droperidol, and thiopental. Second, Fura-2 loaded NG-108 cells were incubated with (+)pentazocine, a selective sigma-1 receptor agonist, and propofol and then its fluorescence was observed after stimulation with bradykinin. Third, male ICR mice received Intrafat or propofol intraperitoneally (i.p.), followed by pentazocine i.p. Brain slices were prepared and Fos-like immunoreactivity was detected using an immunohistochemical method. results: Propofol, droperidol, and dexmedetomidine displaced (+)[(3)H]SKF-10,047 binding in a concentration-dependent manner with Ki50s of 10.2 +/- 0.6, 0.17 +/- 0.03, 5.73 +/- 1.2 microM, respectively. Thiopental sodium was practically ineffective. Propofol produced a statistically significant reduction in the maximal binding capacity (Bmax) but did not affect the dissociation constant (K(d)). (+)Pentazocine significantly enhanced bradykinin-induced [Ca(2+)]i increases, but propofol did not affect it. Pentazocine induced marked Fos-LI positive cells in the posterior cingulate and retrosplenial cortices (PC/RS), which was significantly reduced by propofol.

CONCLUSIONS

These results suggest that propofol may be a sigma-1 receptor antagonist, and that various effects of propofol on the brain may be mediated, at least partly, by the sigma-1 receptor.

The laryngeal tube

The laryngeal tube (VBM Medizintechnik, Sulz, Germany) is a relatively new extraglottic airway, designed to secure a patent airway during either spontaneous breathing or controlled ventilation. In this review article, we have assessed the potential role of the laryngeal tube during anaesthesia and during cardiopulmonary resuscitation. There are four variations of the laryngeal tube: standard laryngeal tube, disposable laryngeal tube, laryngeal tube-Suction II and disposable laryngeal tube-Suction II. The design of the device has been revised several times. Insertion of the standard laryngeal tube is as easy as with the laryngeal mask airway classic. The laryngeal tube may provide a better sealing effect than the laryngeal mask. The incidence of complications with the two devices is similar, although the laryngeal tube may require more re-adjustments of its position to obtain a clear airway. Compared with the ProSeal laryngeal mask, the laryngeal tube may be less effective. The efficacy of the standard laryngeal tube is unclear, particularly in patients breathing spontaneously or in children. The efficacy of the laryngeal tube Suction-II and disposable devices is also not clear. From the limited number of studies and reports available, it can be concluded that the laryngeal tube is potentially useful in maintaining a clear airway during anaesthesia and cardiopulmonary resuscitation. In addition, the device may be useful as an aid to tracheal intubation.

Effects of propofol and thiopental on the central nervous system during nociceptive stimulation in cats

PURPOSE

Nociceptive stimulation may increase central nervous system (CNS) activity during anesthesia. However, it is not known whether propofol and thiopental have a similar inhibitory effect on the CNS during nociceptive stimulation. Therefore, we compared the antinociceptive effects of propofol and thiopental in cats.

METHODS

In 12 cats, anesthesia was induced with 4% halothane in oxygen and maintained with 0.5% halothane in oxygen. The cortical electroencephalogram (EEG) and the electrical activity from the midbrain reticular neurons (R-MUA) were measured before and after sciatic nerve stimulation. The cats were then allocated to receive cumulative doses of either propofol (n = 6) or thiopental (n = 6) i.v. at 5-min intervals. Two minutes after each dose, the cortical EEG and the R-MUA were compared before and after sciatic nerve stimulation.

RESULTS

Propofol and thiopental depressed the basal R-MUA to a similar degree at each dose. Sciatic nerve stimulation increased the R-MUA, and there were no differences in the maximum R-MUA values between propofol and thiopental. The cortical EEGs after each dose of anesthetic without stimulation showed similar patterns, and the patterns of change with stimulation were also similar for these two anesthetics.

CONCLUSION

Propofol and thiopental have similar antinociceptive effects in cats.

Effects of nitrous oxide on the somatosensory evoked response in cats

The effect of nitrous oxide on the activity of the somatosensory system was studied in cats with brain electrodes implanted chronically. The electrodes were implanted in the primary somatosensory cortex, cortical somatosensory radiation, medial lemniscus and midbrain reticular formation. Alterations in the excitability of the primary sensory pathway were assessed by the changes of the input to and output from these brain areas: the response in the medial lemniscus to the stimulation of the skin represented the input to the thalamic relay nucleus and the response recorded in the cortical sensory radiation represented the output from the thalamic relay nucleus. The concentrations of nitrous oxide studied were 50% and 75% in oxygen, and the drug effect was concentration-related. The cortical response to peripheral stimulation was suppressed in amplitude by more than 40% of the control with 75% nitrous oxide, and the response in the cortical radiation was suppressed by 20% of the control with the same dose of nitrous oxide. The response in the cortical radiation to stimulation of the medial lemniscus was suppressed by 20% of the control and the postsynaptic component of the cortical response to the stimulation of the medial lemniscus was suppressed by more than 50% of the control. The multi-unit activity of the brainstem reticular formation was enhanced by nitrous oxide in a dose related manner. The excitability of the thalamic relay nucleus and the primary somatosensory cortex was suppressed by natural slow wave sleep when the reticular multi-unit activity was suppressed, and they were enhanced by paradoxical phase of sleep when the reticular multi-unit activity was enhanced. These findings indicated that the degree of suppression of excitability by nitrous oxide is similar in both the thalamic relay nucleus and sensory cortex, and its action on the brain stem reticular formation is different from that on the primary sensory system. The suppression of sensory functions shown in the present study provides a certain clue to the understanding of the neural basis that though nitrous oxide does not produce deep surgical anesthesia, it does induce potent analgesia and sedation during surgery.

Effect of propofol and isoflurane anaesthesia on the immune response to surgery

There are two major subpopulations of peripheral helper T lymphocytes: T helper 1 (Th1) and T helper 2 (Th2) cells. Surgical stress increases the number of Th2 cells, and decreases that of Th1 cells, resulting in a decrease in the Th1/Th2 ratio, and, consequently, in suppressed cell-mediated immunity. Since anaesthesia can suppress the stress response to surgery, it may inhibit the decrease in the Th1/Th2 ratio. Using flow cytometry, we studied whether propofol anaesthesia (n = 9) or isoflurane anaesthesia (n = 9) had more effect on the decrease in the Th1/Th2 ratio after surgery in patients undergoing craniotomy. The Th1/Th2 ratio decreased significantly after isoflurane anaesthesia (p = 0.011), while it did not change after propofol anaesthesia. The ratio was significantly lower with isoflurane than propofol (p = 0.009). Propofol anaesthesia attenuated the surgical stress-induced adverse immune response better than isoflurane anaesthesia.

Ease of insertion of the laryngeal tube during manual-in-line neck stabilisation

The laryngeal tube has a potential role in airway management during anaesthesia or cardiopulmonary resuscitation. In patients with unstable necks, the head and neck may need to be stabilised manually (manual in-line stabilisation), but it is not known whether this procedure affects the ease of insertion of the laryngeal tube. We studied, in a cross-over study, 21 adult patients to compare the success rate of ventilation through the laryngeal tube between the Magill position (a pillow under the occiput and the head extended) or the manual in-line position of the head and neck (without a pillow under the occiput). After induction of anaesthesia and neuromuscular blockade, the laryngeal tube was inserted in turn in the two positions. The ease of insertion was scored with four categories (easy, moderately difficult, difficult and impossible), and adequacy of ventilation through the device was assessed. Ventilation was adequate in all 21 patients in the Magill position, but only in two of 21 patients during manual in-line positioning (p < 0.01; 95%CI for difference: 68-94%). In the Magill position, insertion of the laryngeal tube was easy in 16 patients and moderately difficult in the remaining five patients; in the manual in-line stabilisation position, insertion was moderately difficult in two patients and impossible in the remaining 19 patients. Stabilisation of the patient's head and neck by the manual in-line method made insertion of the laryngeal tube either difficult or impossible.

Use of the laryngeal tube in 100 patients

BACKGROUND

The laryngeal tube has a potential role during anaesthesia, but there have been only a few studies assessing its efficacy during the entire course of anaesthesia, and all previous studies used prototypes. We studied 100 patients to assess the efficacy of a new laryngeal tube during the entire course of anaesthesia.

METHODS

After induction of anaesthesia, the laryngeal tube was inserted (up to two times) and adequacy of ventilation was assessed. The airway pressure at which gas leaked around the device was measured. The device was used during anaesthesia, while ventilation was controlled. The device was removed after the patient had opened the mouth to verbal command. Any complications during and after anaesthesia were recorded.

RESULTS

Ventilation was possible at the first attempt in 90 patients, at the second attempt in another seven patients, and adequate ventilation failed after two attempts in three patients. Median (interquartile range) leak pressure was 28 (22-30) cmH2O. In all 97 patients, the laryngeal tube was used until the end of surgery. However, in two of the 97 patients the airway was partially obstructed during anaesthesia and it was necessary to reposition the device. The laryngeal tube was tolerated well during emergence from anaesthesia. No hypoxia, regurgitation, vomiting or laryngospasm occurred in any patient. On removal of the laryngeal tube, no blood was detected on the device and no apparent ischaemic changes to the tongue were observed in any patient. Post-operatively, six patients complained of a mild sore throat, and no patient complained of difficulty in swallowing or numbness of the oropharynx.

CONCLUSION

The laryngeal tube can be useful for maintaining a patent airway during anaesthesia.

Comparison of two Macintosh laryngoscope blades in 300 patients

BACKGROUND

There are two forms of Macintosh laryngoscope blade. Compared with the standard blade, the English blade is longer, its curve is more continuous across the entire length of the blade, the flange of the blade continues much closer to the blade tip, and the height of the flange is shorter.

METHOD

We studied 300 patients to compare the ease of laryngoscopy with each type of Macintosh laryngoscope blade. In a random crossover design, after induction of anaesthesia and neuromuscular block, the two blades were inserted in turn, and the views of the glottis at laryngoscopy (Cormack and Lehane scores) were compared.

RESULTS

There was a difference in the view of the glottis in 80 patients. Among these patients, the view was better for the English blade for 63 patients and the standard blade was better for 17 patients. Laryngoscopy was difficult (grade 3 or 4) for at least one blade in 42 of 300 patients (14%). In these 42 patients, there was a difference in the score between the blades in 28 patients; the view was better for the English blade in 25 patients (60%) and for the standard blade in three patients (7%). The view was significantly better for the English blade than for the standard blade (P<0.001; 95% confidence interval 45-74%).

CONCLUSIONS

In patients in whom laryngoscopy was unexpectedly difficult, the English blade provided a better glottic view significantly more frequently than the standard blade.

Inhibitory effect of propofol on ketamine-induced c-Fos expression in the rat posterior cingulate and retrosplenial cortices is mediated by GABAA receptor activation

BACKGROUND

Non-competitive N-methyl-D-aspartate (NMDA) receptor antagonists, including ketamine, have psychotomimetic activities and cause neuronal damage in the posterior cingulate and retrosplenial cortices (PC/RS), which are suggested to be the brain regions responsible for their psychotomimetic activities. We previously demonstrated that ketamine induced marked c-Fos (c-fos protein) expression in the rat PC/RS, which was inhibited by propofol, and the expression was closely related to ketamine-induced abnormal behavior. In the present study, we investigated whether the inhibition by propofol was mediated by GABAA receptor receptor activation.

METHODS

Using Wistar rats, propofol alone, propofol with bicuculline or propofol with flumazenil was injected intravenously and then continuously infused. Fifteen minutes later, 100 mg kg-1 of ketamine or normal saline was injected intraperitoneally. Two hours after the ketamine or saline injection, the brain was extracted and brain sections were prepared, and c-Fos expression was detected using immunohistochemical methods.

RESULTS

Ketamine induced marked c-Fos expression in the PC/RS (171 +/- 9/0.4 mm2), which was significantly inhibited by propofol (5 +/- 5/0.4 mm2). The inhibition by propofol was disinhibited dose-dependently by both bicuculline (0.5 and 1.0 mg kg-1 bicuculline groups: 46 +/- 15 and 143 +/- 16, respectively) and flumazenil (0.1 and 1.0 mg kg-1 flumazenil groups: 79 +/- 6 and 130 +/- 15, respectively).

CONCLUSION

These results demonstrate that the inhibitory effect of propofol on ketamine-induced c-Fos expression in the PC/RS is mediated by GABAA receptor activation, and suggests that ketamine-induced psychoneuronal adverse effects may be suppressed by propofol via the activation of GABAA receptors.

Effect of cricoid pressure on the ease of fibrescope-aided tracheal intubation

We studied the reasons for difficulty with tracheal intubation over a fibrescope, and whether cricoid pressure facilitated intubation, in 50 patients. After induction of anaesthesia and neuromuscular blockade in 10 patients (phase 1), we attempted to clarify the reasons for difficulty in advancing a tracheal tube over an orally-inserted fibrescope, by observing through another fibrescope that was inserted nasally into the pharynx. In the next 40 patients (phase 2), we studied the effect of cricoid pressure on the success rate of tracheal intubation over the fibrescope. After a fibrescope (with a tracheal tube over it) had been inserted orally into the trachea, patients were randomly allocated to receive either criocoid pressure or sham pressure, and the success rate of intubation within 60 s was assessed. In phase 1, the tube was advanced into the trachea without difficulty in three of 10 patients. In the remaining seven patients, the tube impacted on the epiglottis in one patient and on the arytenoid cartilage in another two patients, and the tube migrated into the hypopharynx in the remaining four patients. In phase 2, tracheal intubation was successful within 60 s in seven of 21 patients (33%) without cricoid pressure, compared with 12 of 19 patients (63%) when cricoid pressure was applied (95% CI for difference 2-59%; p = 0.04). We conclude that cricoid pressure facilitates fibrescope-aided tracheal intubation.

Efficacy of the ProSeal laryngeal mask airway during manual in-line stabilisation of the neck

The laryngeal mask airway has a potential role during cardiopulmonary resuscitation, but its placement becomes more difficult during manual in-line stabilisation of the neck, and the device cannot reliably prevent pulmonary aspiration. The ProSeal laryngeal mask airway has a theoretical advantage of reducing aspiration because of its drainage tube, but its ease of placement during stabilisation of the neck is unknown. We studied 20 patients to compare ease of placement and the sealing effect between the standard and ProSeal laryngeal mask airways. In a randomised cross-over fashion, after induction of anaesthesia and neuromuscular blockade, the standard and ProSeal laryngeal mask airways were placed in turn. Placement was significantly easier for the ProSeal laryngeal mask airway (successful at the first attempt in 16 patients and at the second attempt in the remaining four patients) than for the laryngeal mask airway (successful at the first attempt in 12 of 20 patients and at the second attempt in three patients, and failed (> two attempts) in the remaining five patients; p = 0.04). The airway pressure at which gas leaked around the device was greater for the ProSeal than the laryngeal mask airway (mean difference 5.8 cmH2O; 95% CI 2.9-8.7 cmH2O; p = 0.0008).

Analgesia for pelvic and perineal cancer pain by intrathecal steroid injection

BACKGROUND

Corticosteroids are used systemically in patients with advanced cancer to alleviate pain. Intrathecal administration of steroids is rarely performed but analgesic effects of intrathecal steroids have been reported in animal studies. We administered betamethasone intrathecally in three cancer patients with uncontrollable pain.

CASE REPORT

Intrathecal injection of betamethasone (1-4 mg) with saline (total volume = 2 mL) was performed in three patients with advanced pelvic or perineal cancer, in whom pain could not be controlled in spite of various analgesic therapies. After obtaining the patient's informed consent for the procedure, betamethasone was administered intrathecally through the L4/5 intervertebral space. Intrathecal betamethasone produced rapid analgesia within 10 min and subsequent long-lasting analgesia for 5 days or more. Sleep, appetite and activity improved. No adverse effects were observed in any of the patients.

CONCLUSIONS

Intrathecal injection of betamethasone may be a useful approach in some patients with intractable cancer pain.

Caudoputamen is damaged by hypocapnia during mechanical ventilation in a rat model of chronic cerebral hypoperfusion

BACKGROUND AND PURPOSE

Postoperative brain dysfunction, such as delirium, is a common complication of anesthesia and is sometimes prolonged, especially in patients with cerebrovascular disease. In the present study we investigated the effect of hypocapnia during anesthesia on neuronal damage using a rat model of chronic cerebral hypoperfusion.

METHODS

Chronic cerebral hypoperfusion was induced by clipping the bilateral common carotid arteries in male Wistar rats. Fourteen days after the operation, these animals were mechanically ventilated for 2 hours and then kept in suitable conditions for an additional 14 days. Twenty-four rats were assigned to 4 groups: those with chronic cerebral hypoperfusion with either hypocapnia or normocapnia during anesthesia, and those given sham operation with either hypocapnia or normocapnia. White matter lesions in the brain sections were evaluated with Klüver-Barrera staining. Proliferation of glial cells was estimated with the use of immunohistochemistry of glial fibrillary acidic protein, a marker for astroglia, and CD11b, a marker for microglia. Computer-assisted morphometry was applied to the immunohistochemical results of microtubule-associated protein 2 to evaluate the loss of neurons.

RESULTS

The histological damage was localized almost exclusively in the white matter in the rats subjected to chronic cerebral hypoperfusion but without hypocapnia. Neuronal damage and astroglial proliferation occurred with aggravated white matter lesions in the caudoputamen in the rats with chronic cerebral hypoperfusion and hypocapnia. No lesions were observed in sham-operated rats with either hypocapnia or normocapnia.

CONCLUSIONS

These results indicate that hypocapnia during anesthesia causes tissue damage in the caudoputamen, which may be responsible for long-lasting postoperative delirium in patients with stroke and/or dementia.

[A case of atropine-resistant bradycardia in a patient on long-term lithium medication]

A 44-year-old woman was scheduled for laparoscopic cholecystectomy and partial thyroidectomy. She had received lithium, 400-1200 mg daily, and other antidepressants for 10 years for her depressive disorder. Preoperative examination revealed a swelling of the right thyroid associated with hypothyroidism. Her heart rate was in the range of 45-70 min-1 preoperatively. After induction of anesthesia with propofol 50 mg, and fentanyl 100 micrograms, heart rate decreased to 36 min-1 and remained low after tracheal intubation. Atropine sulfate 1.1 mg in divided doses, and ephedrine 4 mg i.v. did not change the heart rate. However, a bolus of isoproterenol 0.02 mg i.v. increased the heart rate to 95 min-1. We suspect that atropine-resistant bradycardia was due to sinus node dysfunction produced by interaction of chronic lithium treatment, fentanyl and propofol. Therefore, an intractable sinus node dysfunction may occur in a patient in whom lithium is given chronically, particularly in whom hypothyroidism is associated. In such a patient, a beta-adrenergic stimulant may be effective in treating bradycardia.

Case report: a normal capnogram despite esophageal intubation

PURPOSE

To report a case of accidental esophageal intubation which could not be detected by capnography.

CLINICAL FEATURES

A 43-yr-old man with osteogenic sarcoma of the mandible underwent mandibulectomy, radical neck dissection, reconstruction of the mandible and radiation therapy. He was scheduled for revision surgery to the mandible. He had a limited mouth opening and neck movement after operation and radiation. After the cuffed oropharyngeal airway (COPA) was inserted, anesthesia was induced with sevoflurane, and fibreoptic nasotracheal intubation attempted, but it was impossible to insert the fibrescope into the trachea because of a deformed larynx. While equipment for tracheostomy was prepared, one last attempt was made to insert the tube blindly into the trachea. The capnograph showed apparently normal carbon dioxide waveforms, and the reservoir bag inflated and deflated regularly. However, immediately after inflation of the cuff of the tracheal tube the reservoir bag movement stopped and CO(2) waveforms disappeared. Fibreoptic bronchoscopy showed that the tube was in fact in the esophagus. It was then noticed that the patient was still breathing spontaneously through the cuffed airway. The patient was awakened and tracheostomy performed. It was considered that egress of the expired gas was partially prevented by the cuffed airway, pooled in the oral cavity, aspirated down the esophagus during inspiration (likely to be due to negative intrathoracic pressure) and pushed out through the tube during expiration; inflation of the cuff prevented the gas entering the esophagus.

CONCLUSION

Under such exceptional circumstances, apparently normal carbon dioxide waveforms were observed despite esophageal intubation in a spontaneously breathing patient.

[A case of diaphragmatic paralysis in a patient with diabetes mellitus after surgery in prolonged prone position]

A 56-year-old woman with diabetes mellitus was scheduled for bilateral kidney lithotomy. She was in the prone position for about seven hours during operation. At the end of operation, arterial blood gas analysis showed PaO2 64 mmHg and PaCO2 44 mmHg under 100% oxygen inhalation through a face mask, and the chest x-rays showed elevation of the right diaphragm. Her trachea was intubated again. The right diaphragm returned to the preoperative level by positive pressure ventilation on supine position. Hypoxemia disappeared when the patient was placed in the sitting position, and the trachea was extubated. The right diaphragm returned to the normal level on the 1st postoperative day, but hypoxia continued until the 6th postoperative day with the patient on supine position. We speculate that the diaphragmatic paralysis was caused by over-extension of the neck for a prolonged period, and that the patient might have been susceptible to nerve injury due to underlying diabetes mellitus.

Tracheal intubation through the intubating laryngeal mask in patients with unstable necks

BACKGROUND

In patients with unstable necks, the neck should be stabilized during induction of anaesthesia, but this may make tracheal intubation difficult. Awake intubation may produce straining, which could be detrimental to the unstable neck.

METHODS

We studied 20 patients with unstable necks to examine the efficacy of insertion of the intubating laryngeal mask under conscious sedation (to minimize the possibility of losing a patent airway and to facilitate fibrescope-aided intubation) followed by tracheal intubation through the laryngeal mask after induction of anaesthesia (to reduce stress response to intubation). After the patient had been sedated with midazolam (up to 5 mg) and fentanyl (up to 100 microg), the intubating laryngeal mask was inserted. General anaesthesia was then induced with sevoflurane and tracheal intubation attempted.

RESULTS

In all patients, tracheal intubation through the laryngeal mask succeeded without airway obstruction. Neither insertion of the mask under conscious sedation nor tracheal intubation after induction of anaesthesia caused straining, and only two patients moved upper extremities at intubation. Insertion of the laryngeal mask did not significantly alter blood pressure or heart rate. Tracheal intubation significantly increased blood pressure and heart rate, but the increase was considered to be small.

CONCLUSIONS

In the patient with an unstable neck with a low risk of pulmonary aspiration, insertion of the intubating laryngeal mask while the patient is sedated may minimize difficulty in obtaining a patent airway before tracheal intubation and may facilitate a fibrescope-aided tracheal intubation; subsequent induction of anaesthesia before tracheal intubation may minimize stress response to intubation.

Airway obstruction in a child with asymptomatic tracheobronchomalacia

PURPOSE

To report a case of airway obstruction with hypoxia during emergence from anesthesia due to unexpected tracheobronchomalacia in a child.

CLINICAL FEATURES

In a previously healthy 22-month-old boy with no symptoms or signs of respiratory disease, general anesthesia was induced by inhalation of increasing concentrations of sevoflurane (up to 5%) in oxygen and a laryngeal mask was inserted. Partial airway obstruction persisted during surgery, but obstruction was relieved by positive-pressure ventilation. During emergence from anesthesia, airway obstruction with hypoxia occurred, necessitating tracheal intubation. Emission of carbon dioxide as well as of sevoflurane was reduced and emergence from anesthesia markedly delayed. Fibreoptic tracheoscopy showed marked collapse of the tracheobronchi during expiration, and a diagnosis of tracheobronchomalacia was made. No respiratory complications occurred postoperatively.

CONCLUSION

Asymptomatic tracheomalacia should also be suspected in case of airway obstruction during anesthesia in young children.