Use of a Combination Lavender/Peppermint Aromatherapy Patch During Port Catheter Placement Under Monitored Anesthesia Care Does Not Reduce Time to Discharge Readiness: A Randomized Controlled Trial

Background: Intraoperative anxiety is a common problem when Monitored Anesthesia Care (MAC) is used instead of general anesthesia during minor surgical procedures such as port catheter placement. Nonpharmacological anxiolytics such as aromatherapy have been studied for their effects on preoperative anxiety, but no placebo-controlled study of aromatherapy during surgeries under MAC has yet been performed. Methods: After IRB approval, 70 patients were randomized 1:1 to receive either a lavender/peppermint aromatherapy patch (Elequil Aromatabs®; Beekley Corporation) or a matching placebo patch. The primary outcome, time to readiness for discharge from postoperative acute care units (PACU; min), was assessed every 15 min until a modified postanesthesia recovery score for ambulatory patients (PARSAP) score of 18 or higher was reached. In the preoperative holding area, the assigned patch/placebo was activated and affixed to a folded towel placed aside the subject's head, contralateral to the side of the planned surgery. The towel and patch/placebo were discarded when the subject left the operating room (OR). Results: No difference was found between the treatment and placebo groups on the primary outcome of time to discharge readiness (mean [standard deviation, SD]: 82 [15] vs. 89 [21] min, respectively, p = 0.131). No difference was found between the treatment and placebo groups on the secondary outcomes of intraoperative midazolam dose, intraoperative opioid dose, intraoperative ondansetron dose, or intraoperative promethazine dose. No difference was found between the treatment and placebo groups in the proportion of subjects requiring rescue postoperative nausea and vomiting (PONV) medication in the PACU or the proportion of subjects requiring opioids in the PACU. No difference was found between the treatment and placebo groups in pain intensity in PACU, average PONV score in PACU, or patient satisfaction in PACU. PACU patient satisfaction was high for both the patch and placebo groups (35/35 [100%] vs. 32/34 [94%] "very satisfied," p = 0.239). Conclusions: Aromatherapy treatment is not indicated intraoperatively to reduce anxiety or the use of antiemetics in patients requiring Port catheter placement. Trial registration: Clinicaltrials.gov, identifier: NCT05328973.

Nasal continuous positive pressure versus simple face mask oxygenation for adult obese and obstructive sleep apnea patients undergoing colonoscopy under propofol-based general anesthesia without tracheal intubation: A randomized controlled trial

STUDY OBJECTIVE

To determine if a nasal positive airway pressure (nasal CPAP) mask would decrease the number of hypoxemic events in obese and obstructive sleep apnea patients undergoing colonoscopy.

DESIGN

Single-center prospective randomized controlled trial.

SETTING

Tertiary academic center.

PATIENTS

We enrolled 109 patients with diagnosis of obesity and/or obstructive sleep apnea scheduled to undergo colonoscopy under propofol general anesthesia without planned tracheal intubation.

INTERVENTION

Patients were randomly allocated (1:1 ratio) to receive supplementary oxygen at a flow of 10 L/min, either through a nasal CPAP or a simple facemask.

MEASUREMENTS

The primary endpoint was the difference in the mean percentage of time spent with oxygen saturation below 90% between the two groups. Secondary outcomes included the need for airway maneuvers/interventions, average SpO2 during the case, duration and severity of oxygen desaturation, incidence and duration of procedural interruptions, and satisfaction and tolerance scores.

MAIN RESULTS

54 were allocated to the simple face mask and 55 to the nasal CPAP mask arms, respectively. A total of 6 patients experienced a hypoxemic event. Among these patients, the difference in the percentage of time spent with oxygen saturation below 90% was not clinically relevant (p = 1.0). However, patients in the nasal CPAP group required less chin lift (20% vs. 42.6%; p = 0.01) and oral cannula insertion (12.7% vs.29.6%; p = 0.03). The percentage of patients with at least one airway maneuver was higher in the simple face mask arm (68.5% vs. 41.8%; p = 0.005). Patient tolerance to device score was lower in the nasal CPAP group (8.85 vs. 9.56; p = 0.003).

CONCLUSIONS

A nasal CPAP did not prevent hypoxemia and should not be used routinely for colonoscopy in obese or OSA patients if a simple face mask is an alternative therapy. However, potential advantages of its use include fewer airway maneuvers or interventions, which may be desirable in certain clinical settings.

TRIAL REGISTRATION

Clinicaltrials.gov, identifier: NCT05175573.

Sustained reduction of discharge opioid prescriptions in an enhanced recovery after thoracic surgery program: A multilevel generalized linear model

BACKGROUND

Enhanced Recovery After Surgery programs have been shown to effectively reduce opioid prescriptions at discharge after their implementation in several institutions, but little is known regarding the sustainability of this effect. Understanding opioid prescribing patterns after long-term implementation of Enhanced Recovery After Surgery initiatives may help guide further opioid prescription reduction and improvements. Our group aimed to determine whether reductions in opioid prescriptions at discharge are sustained in an Enhanced Recovery After Surgery program for thoracic surgery.

METHODS

This retrospective cohort included 2,081 patients undergoing thoracic surgery within a 4-year Enhanced Recovery After Surgery program from March 2016 through April 2020. Our Enhanced Recovery After Surgery protocol included a standardized multimodal analgesic regimen (ie, preoperative gabapentin, tramadol, intercostal nerve block with liposomal bupivacaine, and intraoperative acetaminophen, and ketorolac) and the rest of the interventions recommended by the Enhanced Recovery After Surgery society guidelines. Our primary outcomes were the presence of opioid prescriptions at discharge (hydrocodone, hydromorphone, and oxycodone) and the total opioid amount prescribed (morphine equivalent daily dose). Multilevel generalized linear models were used to account for surgeon variabilities and types of thoracic resection.

RESULTS

Over the study period, the rate of opioid prescriptions at discharge reduced from 35% (Mar 2016) to 25% (Apr 2020), and the amount of opioid prescribed declined from 184 ± 321 morphine equivalent daily dose to 94 ± 251 morphine equivalent daily dose. In multilevel generalized linear models, there was a sustained downward trend in opioid prescriptions over the study period (β -11.8 morphine equivalent daily dose per year, P = .048), which was also directly correlated with the use of minimally invasive surgery (β -84.9 morphine equivalent daily dose for video-assisted thoracoscopic surgery, P < .001; β -139.2 morphine equivalent daily dose for robotic-assisted thoracic surgery, P < .001), intraoperative opioid administration (β -1.4 morphine equivalent daily dose per 1 morphine equivalent dose, P = .026), and the amount of postoperative acetaminophen (β -18.2 morphine equivalent daily dose per 1 g, P = .026). The sustained reduction of opioid prescriptions at discharge did not impact hospital readmission rates within 30 days (odds ratio 1.17, 95% confidence interval 0.86-1.59, P = .306). Subgroup analysis showed a significant, sustained decrease in hydromorphone (β -10.9 morphine equivalent daily dose per year, P = .004), but not for hydrocodone prescriptions (β -5.7 morphine equivalent daily dose per year, P = .168) or oxycodone (β +4.78 morphine equivalent daily dose per year, P = .183).

CONCLUSION

Our Enhanced Recovery After Surgery program for thoracic surgery contributed to a sustained reduction of opioid prescriptions at discharge, which positively correlated with the duration of its implementation and the use of minimally invasive surgical techniques but was negatively impacted by the amount of intraoperative opioid administration.

Emergency tracheal intubation in 202 patients with COVID-19 in Wuhan, China: lessons learnt and international expert recommendations

Tracheal intubation in coronavirus disease 2019 (COVID-19) patients creates a risk to physiologically compromised patients and to attending healthcare providers. Clinical information on airway management and expert recommendations in these patients are urgently needed. By analysing a two-centre retrospective observational case series from Wuhan, China, a panel of international airway management experts discussed the results and formulated consensus recommendations for the management of tracheal intubation in COVID-19 patients. Of 202 COVID-19 patients undergoing emergency tracheal intubation, most were males (n=136; 67.3%) and aged 65 yr or more (n=128; 63.4%). Most patients (n=152; 75.2%) were hypoxaemic (Sao₂ <90%) before intubation. Personal protective equipment was worn by all intubating healthcare workers. Rapid sequence induction (RSI) or modified RSI was used with an intubation success rate of 89.1% on the first attempt and 100% overall. Hypoxaemia (Sao₂ <90%) was common during intubation (n=148; 73.3%). Hypotension (arterial pressure <90/60 mm Hg) occurred in 36 (17.8%) patients during and 45 (22.3%) after intubation with cardiac arrest in four (2.0%). Pneumothorax occurred in 12 (5.9%) patients and death within 24 h in 21 (10.4%). Up to 14 days post-procedure, there was no evidence of cross infection in the anaesthesiologists who intubated the COVID-19 patients. Based on clinical information and expert recommendation, we propose detailed planning, strategy, and methods for tracheal intubation in COVID-19 patients.

Emergency tracheal intubation in 202 patients with COVID-19 in Wuhan, China: lessons learnt and international expert recommendations

Tracheal intubation in coronavirus disease 2019 (COVID-19) patients creates a risk to physiologically compromised patients and to attending healthcare providers. Clinical information on airway management and expert recommendations in these patients are urgently needed. By analysing a two-centre retrospective observational case series from Wuhan, China, a panel of international airway management experts discussed the results and formulated consensus recommendations for the management of tracheal intubation in COVID-19 patients. Of 202 COVID-19 patients undergoing emergency tracheal intubation, most were males (n=136; 67.3%) and aged 65 yr or more (n=128; 63.4%). Most patients (n=152; 75.2%) were hypoxaemic (Sao₂ <90%) before intubation. Personal protective equipment was worn by all intubating healthcare workers. Rapid sequence induction (RSI) or modified RSI was used with an intubation success rate of 89.1% on the first attempt and 100% overall. Hypoxaemia (Sao₂ <90%) was common during intubation (n=148; 73.3%). Hypotension (arterial pressure <90/60 mm Hg) occurred in 36 (17.8%) patients during and 45 (22.3%) after intubation with cardiac arrest in four (2.0%). Pneumothorax occurred in 12 (5.9%) patients and death within 24 h in 21 (10.4%). Up to 14 days post-procedure, there was no evidence of cross infection in the anaesthesiologists who intubated the COVID-19 patients. Based on clinical information and expert recommendation, we propose detailed planning, strategy, and methods for tracheal intubation in COVID-19 patients.

Recent trends in airway management: we are not ready to give up fiberoptic endoscopy

The purpose of this correspondence is to discuss recent findings related to current trends in airway management and to discuss the utilization rates of video laryngoscopes versus traditional techniques in USA, UK, and Canada. To highlight the increased use of video laryngoscopes in difficult airway situations, data on the use of alternative airway devices at our institution collected from 2008 to 2010 are presented alongside the results of previously published surveys collected from 2002 to 2013.

Nonsurgical airway management training for surgeons

PURPOSE

Airway management occupies a crucial component of surgical education. As such, it can be difficult to provide adequate training within the hospital setting alone. To be facile in all aspects of nonsurgical airway management, the surgical resident must have thorough cognitive understanding of the process as well as technical mastery. The Department of Surgery at the Methodist Hospital in Houston has developed a curriculum for nonsurgical airway management that uses multiple modalities for education, reinforcement, and testing. Didactic lectures based on established national guidelines are provided as a foundation. This method is supplemented by hands-on group scenarios that use inanimate models. Throughout the course, faculty leaders provide guidance and skills assessment. Residents are tested for competency using core value checklists based on knowledge and technical proficiency. During its pilot year, the curriculum has proven its need and success in residency education. Future improvements include development of specific clinical scenarios as well as integration of more advanced educational equipment and models for use in nonsurgical airway management.

DEVELOPMENT OF THE ACTIVITY AND MATERIALS

Materials used for this program include an article by the American Society of Anesthesiologists Task Force on Management of the Difficult Airway, the New England Journal of Medicine article entitled "Videos in clinical medicine. Orotracheal intubation" by Kabrhel et al,(2) "Management of the difficult and failed airway" by Hung and Murphy,(3) the American Heart Association Airway Management course 2007,(4) and the Manual of Emergency Airway Management by Walls et al.(5) EVALUATION COMPONENT: Before participating in the module, residents completed a written pretest and performed an initial simulation to establish a baseline. Residents then worked through a series of skills that provided experience in both the cognitive and the procedural aspects of airway management. To complete the module successfully, residents were required to attend three 3-hour sessions. After supervised practice, residents were tested on the procedural techniques via a procedural checklist and cognitive aspects with respect to emergency, crash, difficult, and failed airway algorithms.(1,5) The simulations are based on the 2003 American Society of Anesthesiologists Task Force on Management of the Difficult Airway Algorithms(1) and emergency, crash, difficult, and failed airway algorithms.(2,5) PROPOSED OUTCOME MEASURES: Proposed long-term outcome measures will include evaluations from faculty on a resident's noninvasive airway management skills and the resident's self-evaluation in actual noninvasive airway management situations. Resident performance will be evaluated by faculty using standardized checklists, review of simulation parameters, and review of audio-video recording of the simulation.

EXPERIENCE TO DATE

This article describes our first implementation in the evolution of this module. The module was introduced to residents at all postgraduate levels in September 2007. Scores on pretests and performance on initial simulations were similar in all postgraduate years, with minimally superior pretest and initial simulation performance from the senior residents. Correct procedural adoption occurred rapidly after prebriefing and initial hands-on demonstration and supervised practice in simulated patient scenarios on airway mannequins.

CONCLUSIONS AND NEXT STEPS

Our preliminary experience with a nonsurgical airway management training module for surgical residents has shown that a need for training exists in this critical area. Correct procedural adoption occurred rapidly after a didactic and procedural hands-on experience. Time intervals needed for review to maintain competence will also be studied. Improvements to the proficiency criteria and simulations are underway.

The Use of the Laryngeal Mask Airway During Guidewire Dilating Forceps Tracheostomy

Percutaneous tracheostomy has become a common alternative to the classical open tracheostomy because of its convenience, cost effectiveness, and decreased complication rates. We retrospectively reviewed our intensive care practice using a guidewire dilatating forceps percutaneous tracheostomy technique with an endotracheal tube, as compared with the Classic Laryngeal Mask Airway (LMA) for these procedures. From 1998 to 2004, 274 patients underwent a tracheostomy procedure. Two-hundred-fifty-four (92.7%) of these patients underwent a guidewire dilatating forceps tracheostomy and 20 (7.3%) underwent a surgical tracheostomy. In the guidewire dilatating forceps group, 188 (74%) were performed by endoscopy via LMA-guided bronchoscopy, and 66 (26%) were performed through an endotracheal tube. Endoscopic views obtained via the LMA were subjectively better than those obtained with the endotracheal tube. Acute complications were significantly more frequent when using an endotracheal tube as compared with the LMA (6 of 66 versus 4 of 188; P = 0.022 Fisher's exact test, odds ratio = 4.6). There was a significant difference in terms of acute (10 of 254 versus 6 of 20; P < 0.001, odds ratio = 10.5) and chronic (0 of 254 versus 4 of 20; P < 0.001) complications between the 2 groups. There were no ventilatory complications or reports of gastric aspiration. The LMA provides a safe and effective alternative to an endotracheal tube for airway management during guidewire dilatating forceps tracheostomies in selected patients.

An Evaluation of the Insertion and Function of a New Supraglottic Airway Device, the King LT ™, During Spontaneous Ventilation

Trials of the King LT trade mark (LT, King Systems, Noblesville, IN) in controlled ventilation of the lungs have shown that it is an effective supraglottic airway device. We designed this study to evaluate the King LT regarding ease of insertion, position within the airway, and anatomic sealing properties during spontaneous ventilation in 50 ASA physical status I-III, Mallampati I-III, adult patients undergoing routine general anesthesia. Anesthesia was induced with up to 2 microg/kg fentanyl and 1.5-2 mg/kg propofol and maintained with 70% N2O/30%O2 and isoflurane. Insertion time, oropharyngeal leak pressures, fiberoptic position, and spirometry and hemodynamic data were recorded. Any complications were noted. Insertion was determined to be easy and a patent airway was achieved in all patients. First, second, and third attempt insertion rates were 86%, 12%, and 2%, respectively. Time to place the King LT trade mark was <5 s in 90% of cases. Baseline leak pressures were 31 +/- 8.8 cm H2O (17-50 cm H2O). Complications included laryngospasm (1) and coughing (3) on extubation. The incidence of sore throat at 1 h and 24 h postoperatively was 22% and 15%, respectively. The King LT trade mark is a simple and reliable supraglottic airway device for airway management during spontaneous ventilation.

Complications of managing the airway

The inability to secure the airway, with consequent failure of oxygenation and ventilation, is a life-threatening complication. Failure of oxygenation leads to hypoxia followed by brain damage, cardiovascular dysfunction, and finally death. Time is a very crucial factor in this context. Complications vary widely in severity; while some are dramatic and immediately life-threatening (unrecognized esophageal intubation), others can be severe and long-lasting (nerve injuries) or mild and short-lived (sore throat). To minimize injury to the patient, the anesthesiologist should examine the patient's airway carefully, identify any potential problems, devise a plan that involves the least risk for injury, and have a back-up plan immediately available. Each anesthesiology department should establish guidelines/algorithms specific to their institution. Unfortunately, a reliable test for detecting all patients at risk does not exist.

The laryngeal tube for difficult airway management

BACKGROUND AND OBJECTIVE

Since the introduction of the laryngeal mask into clinical practice, various additional supraglottic ventilatory devices have been developed. Although it has been demonstrated that the laryngeal tube is an effective airway device during positive pressure ventilation no clinical study has been performed thus far regarding its use in patients with predicted ventilation and intubation difficulties.

METHODS

The aim of this study was to prospectively evaluate the use of the laryngeal tube for temporary oxygenation and ventilation in adult patients with supraglottic airway tumours scheduled to undergo a pharyngeal-laryngeal oesophagoscopy and bronchoscopy under general anaesthesia. In addition to our standard airway management with face mask ventilation and rigid bronchoscopy, all patients were temporarily ventilated with an laryngeal tube. Also, in patients requiring laryngeal biopsies, endotracheal intubation was performed with a 6.0 mm microlaryngeal tracheal tube. Minute ventilation volumes, tidal volumes, ventilation pressures, end-expiratory CO2 concentration, oxygen saturation and arterial blood gas samples were measured.

RESULTS

From 54 enrolled patients only patients with relevant tumour masses were evaluated (n = 23). Mask ventilation was performed without difficulty in 15 of 23 patients. Mechanical ventilation with the laryngeal tube was possible in 22 of 23 patients with an audible leak present in three. Conventional endotracheal intubation was successfully performed in 19 of 23 patients. During face mask ventilation, minute volume, tidal volume, ventilation pressure, end-tidal CO2, oxygen saturation and arterial PO2 were significantly lower and PCO2 significantly higher (P < 0.05, paired t-test). No statistically significant differences were noted between the laryngeal tube and the microlaryngeal tracheal tube.

CONCLUSIONS

The possibility of difficult ventilation and intubation must always be considered, in patients with supraglottic airway tumours. In these cases, the laryngeal tube can be considered for routine airway management and may be useful in the 'cannot-intubate' situation although difficulties should be anticipated in patients with previous irradiation, specifically of the throat area.

Risk Factors Assessment of the Difficult Airway: An Italian Survey of 1956 Patients

Over the last decade, there has been a heightened awareness and an increase in the amount of literature being published on recognition and prediction of the difficult airway. During the preoperative evaluation of the airway, a thorough history and physical specifically related to the airway should be performed. Various measurements of anatomic features and noninvasive clinical tests can be performed to enhance this assessment. In this study we correlated the Mallampati modified score and several other indexes with the laryngoscopic view to identify anatomical and clinical risk factors related to the difficult airway. We prospectively collected data on 1956 consecutive patients scheduled to receive general anesthesia requiring endotracheal intubation for elective surgery. The Mallampati classification versus the Cormack-Lehane (C-L) linear correlation index was 0.904. A Mallampati Class 3 correlated with a C-L Grade 2 (0.94), whereas a Mallampati Class 4 correlated with a C-L Grade 3 (0.85) and a C-L Grade 4 (0.80). Operator evaluation, performed by a simplified tracheal intubation difficulty scale, showed a linear correlation of 0.96 compared with the C-L groups. Although there is a correlation between oropharyngeal volume and difficult intubation, the Mallampati score by itself is insufficient for predicting difficult endotracheal intubation.

Prediction of difficult laryngoscopy in obese patients by ultrasound quantification of anterior neck soft tissue

In 50 morbidly obese patients, we quantified the soft tissue of the neck from the skin to the anterior aspect of the trachea at the vocal cords using ultrasound. Thyromental distance, mouth opening, limited neck mobility, modified Mallampati score, abnormal upper teeth, neck circumference and sleep apnoea were assessed as predictors of difficult laryngoscopy. Of the nine (18%) cases of difficult laryngoscopy, seven (78%) had a history of obstructive sleep apnoea, compared with two of the 41 patients (5%) in whom laryngoscopy was easy (p < 0.001). Patients in whom laryngoscopy was difficult had more pretracheal soft tissue (mean (SD) 28 (2.7) mm vs. 17.5 (1.8) mm; p < 0.001) and a greater neck circumference (50 (3.8) vs. 43.5 (2.2) cm; p < 0.001). None of the other predictors correlated with difficult laryngoscopy. We conclude that an abundance of pretracheal soft tissue at the level of the vocal cords is a good predictor of difficult laryngoscopy in obese patients.

Difficult airway management patterns among attending anaesthetists practising in Israel

BACKGROUND AND OBJECTIVE

In recent years, a large number of airway devices have been introduced into clinical practice as adjuncts to the management of the difficult airway. The purpose of this study was to evaluate the practices of Israeli anaesthetists in specific clinical situations and their familiarity with the use of a variety of airway devices and techniques.

METHODS

A survey developed in our institution was sent to 300 attending anaesthetists representing all board-certified anaesthetists practising in Israel.

RESULTS

Of the 153 respondents, 75% belonged to university hospitals. Ninety-six percent were skilled with laryngeal mask airways and 73% with fibreoptics. Seventy percent preferred regional anaesthesia with anticipated difficult intubation, continuation of anaesthesia with a laryngeal mask with failed intubation and a laryngeal mask for impossible mask ventilation. For the airway scenarios, awake fibreoptic, awake direct laryngoscopy, intubation under inhalation anaesthesia and tracheostomy were shared equally.

CONCLUSIONS

There is a high degree of adherence by Israeli anaesthetists to the American Society of Anesthesiologists' difficult airway algorithm. Current airway management practice patterns in Israel are presented.

The incidence of class "zero" airway and the impact of Mallampati score, age, sex, and body mass index on prediction of laryngoscopy grade

IMPLICATIONS

In an earlier study we proposed the addition of a new airway class, zero (visualization of the epiglottis), to the four classes of the modified Mallampati classification. In this prospective study, 764 surgical patients were assessed with regard to their airway class (including class zero), laryngoscopy grade, and the effect of the airway class and other predictors on the laryngoscopy grade.

Etiology and incidence of endotracheal intubation following spinal anesthesia for cesarean section

BACKGROUND

The incidence of spinal failure necessitating general anesthesia and endotracheal intubation following spinal anesthesia for cesarean section is extremely low. Aspiration prophylaxis prior to spinal anesthesia is often recommended in case of spinal failure or excessive spinal block requiring the emergency administration of general anesthesia.

OBJECTIVES

To determine the incidence of endotracheal intubation following spinal anesthesia for cesarean section.

METHODS

We retrospectively reviewed the peri-operative course of parturients undergoing cesarean section under spinal anesthesia at our institution from February 1991 to December 1993. If spinal failure occurred, 10 ml of sodium bicarbonate was administered by mouth prior to induction of general anesthesia.

RESULTS

Among the 743 cases that we reviewed, spinal failure occurred in 15 patients (2%) because of inadequate analgesia in 14 patients (1.9%) and unexpected prolonged surgery for hysterectomy in one patient (0.1%). No patient required intubation due to excessive spinal block. In none of the patients was a record of pulmonary aspiration identified.

CONCLUSIONS

The extremely low incidence of spinal failure or excessive block necessitating endotracheal intubation suggests that routine aspiration prophylaxis may not be necessary prior to spinal anesthesia. However, these results should be confirmed by a prospective, controlled study on larger populations. An antacid should be readily available and administered whenever general anesthesia is required.

Linkage analysis of candidate regions in Swedish nonsyndromic cleft lip with or without cleft palate families

OBJECTIVE

To analyze linkage of five candidate regions for nonsyndromic cleft lip with or without palate (CLP) on chromosome 2p13, 4q, 6p23, and 19q13; in addition chromosome 1q32, the locus for van der Woude syndrome, on Swedish CLP families.

DESIGN

Three to five linked microsatellite markers were selected from each candidate region. Polymerase chain reaction (PCR) with fluorescent-labeled microsatellite markers was performed on DNA samples from the participating families. Electrophoresis of the PCR products was performed on a laser-fluorescent DNA sequencer. The genotype data were analyzed with multipoint linkage analysis. Modes of inheritance tested included two autosomal dominant, an autosomal recessive, and a nonparametric model. Multipoint logarithm of odds (LOD) scores were also calculated by assuming genetic heterogeneity.

PARTICIPANTS

Nineteen Swedish multigenerational families with at least two first-degree relatives affected with CLP. Greater than 50% of the families studied show vertical transmission of the clefting phenotype and both inter- and intrafamilial variability were noted.

RESULTS

Cumulative multipoint LOD scores for the whole group of families calculated under autosomal dominant modes of inheritance were negative in all regions and less than -2 except chromosome 6p23. LOD scores calculated under recessive inheritance and the nonparametric model were inconclusive. There was no significant evidence of genetic heterogeneity among the sample group.

CONCLUSIONS

The group of Swedish CLP families did not demonstrate significant linkage to any of the five candidate regions examined. This might suggest a new but yet unknown CLP locus or loci in this family group. However, because linkage could not be excluded in some individual families, they should still be tested with candidate genes from these regions.

Clinical and genetic studies of Van der Woude syndrome in Sweden

Van der Woude syndrome (VWS) is an autosomal dominant craniofacial disorder characterized by pits of the lower lip, hypodontia and cleft lip and/or cleft palate. It has been reported as the most common form of syndromic orofacial clefting with very high penetrance and varied expressivity. The disease locus for VWS has been mapped to chomosome 1q32, but the gene is yet to be cloned. Here we report a total of 11 Swedish VWS patients: 9 familial cases from two families and two isolated cases. Clinical examination of these patients showed phenotypic variability, even between patients from the same family. Genetic studies were performed using four microsatellite markers from chromosome 1q32. Constitutional deletion in this region was not demonstrated in any of the familial or isolated cases. However, in the two VWS families, linkage analysis using these markers showed positive LOD (logarithm of the odds) scores ranging from 2.56 to 2.88 to all individual markers. The highest LOD score of 3.75 was obtained with the combined haplotypes of D1S491 and D1S205, thus confirming linkage of VWS in these two families to 1q32. We conclude that there is varied expressivity but no evidence of genetic heterogeneity in VWS.

Incidence of cleft lip and palate and risks of additional malformations

OBJECTIVE AND METHODS

Children with cleft lip and/or palate (n = 251) born between 1991 and 1995 in the county of Stockholm, Sweden, were studied with reference to incidence and rate ratios (RRs) of different types of clefts, gender, birth weight, mother's age, and length of pregnancy. Children who had clefts and additional malformations were compared with children who had clefts but no additional malformations.

RESULTS

The incidence of clefts was 2.0/1000 live births, and it was higher among males than among females. The RR, an index of relative risk, was 1.58. The main groups, children with isolated cleft lip, children with cleft lip and palate, and children with isolated cleft palate, showed similar incidence values (0.6-0.7/1000 live births). Children with bilateral clefts had an incidence of 0.3/1000 live births. Additional malformations were found in approximately every sixth newborn with a cleft when children with Robin sequence were excluded. There was a tendency for newborns with bilateral clefts to have additional malformations (RR = 1.36; confidence interval = 0.74-2.49). Children with clefts and additional malformations had lower birth weight and were born earlier than children with clefts only.

CONCLUSION

Preterm cleft children with low birth weight should be screened for the presence of other birth defects.

Musculoskeletal symptoms and psychosocial factors among patients with craniomandibular disorders

General musculoskeletal symptoms and emotional stress situations in terms of psychosocial stressors at work and sleeping disturbances were compared between patients with craniomandibular disorders (CMD) (56 women, 24 men) and a random population sample (88 men, 86 women in the Stockholm Music 1 study). A multiple-choice questionnaire was used. In comparison with the CMD men the CMD women had an increased rate of tooth clenching and muscular pain in the face. When compared with the women in the population sample, the CMD women showed increased risks for musculoskeletal pain in various parts of the body, such as neck, shoulders, thoracic back, wrist/hands, and the knees. A comparison between the CMD men and the men in the population did not show any clear differences in prevalence of general musculoskeletal symptoms. However, the CMD men differed in reporting higher scores for psychologic demands at work and also in having more sleeping disturbances.

The alignment of permanent mandibular incisors in children. A longitudinal prospective study

The aim was to study the alignment of mandibular incisors before and after eruption of the canines, and if possible to find a method of predicting space deficiency. Fifty-three children with normal occlusion or untreated mild post-normal occlusion had plaster models taken at 7, 9, 10, and 13 years of age. An estimation of the space situation for the mandibular incisors was made using a scale with five levels. Measurements of intercanine distance, width of each incisor and space available between the canines were made. Greater crowding was seen before the eruption of permanent canines than after the start of eruption. Estimation of space showed significant correlations to measurements of inter-canine distance. Children with an excess of incisal space had a wider mandibular inter-canine distance compared with those with a deficiency of space. Among 7-, 9-, and 10-year-old children an inter-canine distance of less than 26 mm was associated with crowding. A distance of 28 mm or more was estimated as no risk for crowding.

Shear bond strength of ceramic brackets with chemical or mechanical retention

The study was undertaken to measure and compare the shear bond strengths of a ceramic bracket with chemical retention, a ceramic bracket with a new type of textured base providing mechanical retention, and a metal bracket with foil-mesh base. The tests were performed on 51 extracted human premolars which were randomly divided into three equally large groups (n = 17)--one group for each type of bracket. After debonding, the site of failure was noted and the enamel surface inspected with scanning electron microscopy. The ceramic bracket with chemical retention exhibited significantly higher bond strength than the corresponding bracket with textured base. In comparison with the metal bracket significantly higher bond strengths were recorded for both types of ceramic brackets. The ceramic bracket with mechanical retention and the metal bracket were comparable as regards the site of bond failure. In some cases the chemical bond provided very high values of bond strength. Enamel failure were recorded in three teeth which had been bonded with this type of ceramic bracket.

Changes in maximum bite force related to extension of the head

The maximum bite force and position of the hyoid bone during natural and extended head posture were studied in 15 adults. All participants had normal occlusions and full dentitions. In addition, there were no signs or symptoms of craniomandibular disorders. The bite force was measured with a bite force sensor placed between the first molars. Six registrations of gradually increasing bite force up to a maximum were made with randomized natural and extended head postures. With one exception, the mean maximum bite force value was found to be higher for every subject with extended head posture compared to natural head posture. The sample mean was 271.6 Newton in natural head posture and 321.5 Newton with 20 degrees extension. With changed head posture, the cephalometric measurements pointed towards a changed position of the hyoid bone in relation to the mandible and pharyngeal airway. The cephalometric changes in the position of the hyoid bone could be due to a changed interplay between the elevator and depressor muscle groups. This was one factor which could have influenced the registered maximum bite force.

Muscular tenderness evaluated by surface EMG frequency analysis of isometric contractions

Myoelectric power spectrum analysis was used to compare muscular activity in the masseter and anterior temporal muscles between patients with tender masseter muscles and healthy controls. Surface EMG was recorded for 28 patients and nine controls while they were biting on a bite force transducer during a period of 10-15 s up to maximal effort (100% MVC). The mean frequency (MF) was calculated as a single estimate of the myoelectric power spectrum. Regression analyses of MF's for the masseter muscles versus the force level 0-60% MVC showed significantly less steep slopes of regression for the patients compared interindividually with the controls. As regards the anterior temporal muscles there was no significant difference between groups. One explanation for the difference in MF's for the masseter muscles between patients and controls is that the patients suffered an inhibition or difficulty in recruiting motor units. Different firing rate properties for motor units at high force levels (60-100% MVC) could be one reason for a significantly smaller decrease in MF for the patients' elevator muscles than for the controls.

Surface EMG amplitude and frequency dependence on exerted force for the upper trapezius muscle: a comparison between right and left sides

Surface electromyographic (EMG) amplitude and mean power frequency (MPF) were used to study the isometric muscular activity of the right versus the left upper trapezius muscles in 14 healthy right-handed women. The EMG activity was recorded simultaneously with force signals during a 10-15 s gradually increasing exertion of force, up to maximal force. Only one side at a time was tested. On both sides there was a significant increase in EMG amplitude (microV) during the gradually increasing force from 0% to 100% maximal voluntary contraction (MVC). The right trapezius muscle showed significantly less steep slopes for regression of EMG amplitude versus force at low force levels (0%-40% MVC) compared intra-individually with high force levels (60%-100% MVC). This was not found for the left trapezius muscle. At 40% MVC a significantly lower MPF value was found for the right trapezius muscle intra-individually compared with the left. An increase in MPF between 5% and 40% MVC was statistically significant when both sides were included in the test. The differences in EMG activity between the two sides at low force levels could be due to more slow-twitch (type I fibres) motor unit activity in the right trapezius muscles. It is suggested that this is related to right-handed activity.

Surface EMG frequency dependence on force in the masseter and the anterior temporal muscles

Myoelectric power spectrum analysis was used to study isometric contractions, 10-15 s long, of the masseter muscles and the anterior temporal muscles. Surface EMG activity was recorded from these muscles for nine females while biting on a bite force transducer up to maximal effort (100% maximal voluntary contraction; MVC). The mean frequency (MF) was calculated as a single estimate of the myoelectric power spectrum. Regression analyses were made of MF versus bite force (0-100% MVC). The mean MF values of all females' masseter muscles increased up to 55-60% MVC. For the anterior temporal muscles no increase in mean MF was found above 20-25% MVC. The increase in MF was possibly dependent on recruitment of type I fibers and low-pass tissue filtering effects. The slope of regression for the force level 0-60% MVC was intraindividually steeper for the masseter muscles than for the anterior temporal muscles. A similar decrease in mean MF was found for the masseter muscles and the anterior temporal muscles for the force level 60-100% MVC. The possibility of muscular fatigue was discussed.

Changes in the surface electromyogram during increasing isometric shoulder forward flexions

When using electromyographic techniques in the evaluation of muscular load it is necessary to determine the mathematical relationship between the torque and the amplitude of the electromyographic signal. Isometric gradually increasing contractions up to 100% MVC can then be used. Often more than linear increases for the amplitude (RMS)--force regression have been reported. The present study was designed to test whether changes in power spectral density function take place during a gradually increasing isometric contraction (duration 10 s). Twenty-two clinically healthy females performed an increasing isometric shoulder forward flexion for 10 s using an isokinetic dynamometer. Electromyographic activity was measured in trapezius, deltoid, infraspinatus and biceps brachii using surface electrodes. Mean torque values were determined together with mean power frequency (MPF) and root mean square values (RMS) from the EMG signals for each 256 ms period. The RMS-torque regressions showed higher regression coefficients during the 6th to 9th sec than during the first 5 s. No significant correlation existed between MPF for the four muscles and the torque. A gradual decrease in MPF was generally found from the 6th s. It is concluded that this decrease in power spectral density function might have contributed to the significantly higher regression coefficient for the RMS torque regression at the high output part of the gradually increasing isometric contraction.

The amplitude distribution of electromyographic activity in painful masseter muscles during unilateral chewing

The aim of this study was to investigate whether the amplitude distribution of electromyographic activity (EMG) in terms of muscular load revealed any differences between patients with painful masseter muscles and referents during the chewing of an almond and of gum. The relative masticatory forces of the masseter muscle and the anterior temporal muscle during chewing were calculated by a transformation of the muscular load levels of EMG activity (microV) to load levels of relative masticatory force (%RVC). This was done by regression in reverse of an isometric reference voluntary contraction (RVC) for EMG versus bite force biting on a bite-force sensor. The maximal bite-force values for patients and referents were similar. The relative masticatory force for chewing an almond was higher than that for gum-chewing. The peaks of the relative masticatory forces were similar for both patients and referents. During the chewing of an almond the relative masticatory forces of the masseter muscle below the peak load were higher for patients than referents. During gum-chewing the patients used higher forces than referents for 70% of the total chewing time analysed. This also applied to the anterior temporal muscle when chewing an almond. Estimates of the peak masticatory forces were calculated in newtons.

EMG versus force relationship in painful masseter muscles before and after intramuscular anesthetics and saline injections

Electromyographic (EMG) activity of masseter and anterior temporal muscles, and bite force were analyzed in 28 young, fully dentate women with painful and tender masseter muscles before and after intramuscular injection of either lidocaine or saline in superficial masseter muscle. EMG-activity of the descending part of the trapezius muscle during increased bite force was also analyzed. As regards the mandibular elevators, the intraindividual relationship between slopes for EMG-force regression at low and high contraction levels before injection were the same as for healthy women investigated previously. Intramuscular injection of lidocaine reduced postural EMG-activity of the masseter muscles and EMG-force regression curve became less steep at low contraction levels. After saline injections no changes in EMG-activity were found. The EMG-activity of the descending part of the trapezius muscle was increased significantly for the total group during the strongest bite.

The amplitude distribution of electromyographic activity of masticatory muscles during unilateral chewing

The amplitude probability distribution function (APDF) of electromyographic activity was used to describe the variation in relative masticatory force in the superficial masseter muscle and the anterior temporal muscle during unilateral chewing. The masticatory force, predicted from an isometric reference contraction, increased significantly in both muscles when chewing an almond compared to chewing half a stick of gum. Analysis of the distribution levels of contraction showed that the significant differences in relative masticatory forces were found for high levels of contraction. The individual variations were large when masticatory force between the muscles was compared. Maximal loading of the masseter muscle and the anterior temporal muscle exceeded 100% of the reference voluntary contraction in six females out of nine, mainly during chewing of an almond. The results indicated that APDF can be useful for analysing chewing when estimations of relative masticatory force and a measure of the distribution of different levels of contractions are desirable.

Discomfort and bite force in painful masseter muscles after intramuscular injections of local anesthetic and saline solution

Thirty women with a history of daily pain in the masseter muscles were injected with either lidocaine or saline. The participants were told that they were being given an anesthetic injection to reduce their muscular discomfort. The dentist performing the injections did not know which fluid was used. The discomfort in the masseter muscle was assessed by using Borg's new rating scale before and 10 minutes after injection. The evaluation was followed up on day 1, day 3, and day 7. Bite force was registered between the first molars on the injection side. When scale values were compared individually within groups before and after injection, a significant decrease in discomfort was found in both groups, with the exception of day 1 for the lidocaine group and days 1 and 3 in the saline group. The total lidocaine and saline groups assessed the discomfort similarly except on day 3 when the lidocaine group showed significantly less discomfort. The intraindividual force values increased significantly after injection in the saline group. This effect was not found in the lidocaine group. Despite the minor tendencies for lidocaine to have a better effect, the placebo effect was considered to be high and important.

Regression analysis of electromyographic activity of masticatory muscles versus bite force

Electromyographic (EMG) activity of the superficial masseter and the anterior temporal muscles versus the bite force was studied in 10 young women. They were fully dentate and had no dysfunction of the stomatognathic system. The descending part of the trapezius muscle was also chosen for EMG registration. The average bite force between the first molars was 396 N (Newton). Steeper slopes for the EMG versus force regression curve at high contraction levels than at low contraction levels for the superficial masseter muscle may indicate that this muscle has a recruitment pattern that differs from that of the anterior temporal muscle. In the case of the anterior temporal muscle there was no difference between the slopes for the EMG-force regression at low and high contraction levels. There was significantly increased activity in the descending part of the trapezius muscle mainly during high bite force levels in half the subjects.

Role of brushing technique and toothbrush design in plaque removal

Twenty-four adults participated in an intraindividual crossover experimental study to compare the plaque removing ability of straight multitufted and V-shaped brushes. Twelve of the participants had loss of periodontal tissue resulting in open but healthy interdental areas while the other 12 displayed no periodontal breakdown. In part 1 the participants were asked to brush their teeth using their own brushing technique and length over two 12-day periods during which time they, at random, used one brush for the first and the other brush for the second period. In part 2 the participants were professionally brushed by two dental assistants using four brushing techniques (The Bass, The Roll, The Circular Scrub and The Horizontal Scrub) randomly assigned to the four quadrants of the mouth. Cleaning was performed once a day for two 5-day periods, during which time the participants refrained from brushing and interdental cleaning. Initial toothbrush assignment was randomized. At the beginning of the study and each test period no plaque or gingival inflammation was visible. At the end of each period the accumulated plaque was registered. The results showed that there was no difference between the two brushes tested in the unsupervised part. The plaque removing ability when using either of the brushes varied between participants. When professionally used the straight multitufted and V-shaped toothbrushes did not show any difference in plaque removal on buccal and lingual surfaces. Interproximally the V-shaped toothbrush was better at plaque removal than the straight one.(ABSTRACT TRUNCATED AT 250 WORDS)