The minimal leak test technique for endotracheal cuff maintenance

Endotracheal tube (ETT) cuff pressure management is an essential part of airway management in intubated and mechanically ventilated patients. Both under- and over-inflation of the ETT cuff can lead to patient complications, with an ideal pressure range of 20-30 cmH₂O defined. A range of techniques are employed to ensure adequate ETT cuff inflation, with little comparative data. We performed an observational cross-sectional study in a tertiary metropolitan ICU, assessing the relationship between the minimal leak test and cuff manometry. Forty-five mechanically ventilated patients, over a three-month period, had ETT cuff manometry performed at the same time as their routine cuff maintenance (minimal leak test). Bedside nurse measurements were compared with investigator measurements. At the endpoint of cuff inflation, 20 of 45 patients (44%) had cuff pressures between 20 and 30 cmH₂O; 11 of 45 patients (24%) had cuff pressures <20 cmH₂O; 14 of 45 patients (31%) had cuff pressures ≥30 cmH₂O. Univariate analysis demonstrated an association between both patient obesity and female gender requiring less ETT cuff volume (P=0.008 and P <0.001 respectively), though this association was lost on multivariate analysis. No association was demonstrated between any measured variables and cuff pressures. Inter-operator reliability in performing the minimal leak test showed no evidence of bias between nurse and investigators (Pearson coefficient = 0.897). We conclude the minimal leak test for maintenance of ETT cuffs leads to both over- and under-inflation, and alternative techniques, such as cuff manometry, should be employed.

Artefacts produced by suture traction during incisional biopsy of oral lesions

The aim of this study is to compare the artefacts ascribed to the technique of incisional biopsy using a punch or scalpel and the influence of suture use for traction and delivery of the specimen. A total of 160 samples were obtained from 10 fresh pig tongues by four experienced oral surgeons. Handling artefacts (squeeze artefacts): crush, splits, fragmentation and pseudocysts were assessed. No differences were identified in terms of crush, fragmentation or pseudocysts between samples obtained with a punch or scalpel. Splits were more frequent in those biopsies taken with a scalpel (chi2 = 9.26; P= 0.0023). Artefacts in the punch biopsy group were significantly less than in the group that combined punch and suture traction (P < 0.01). The scalpel and suture traction group showed significantly more artefacts than the group without suture. It is concluded the use of a stitch for traction in small incisional biopsies causes squeeze artefacts, so its use should be restricted to specimen orientation.

Survival to oral cancer. A study of clinical risk markers with independent prognostic value

BACKGROUND

The aims of this study have been to describe survival to oral cancer and to identify clinical variables with independent influence on its prognosis before treatment.

METHODS

94 oral cancer patients treated during 1991-99 entered the study. The variables considered were: age, sex, location of the lesion, clinical presentation, symptoms, TNM classification, months elapsed since treatment and ploidy pattern. A descriptive study of the data was performed, along with a survival analysis using Kaplan-Meier curves (log rank test for comparison among curves) and single and multivariate Cox regression.

RESULTS

Multivariate analysis recognized a prognostic value for the age of the patient (OR = 1.06; CI95%: 1.02-1.09) and also for tumour size. Tumour stage resulted also selected, but its predictive value was lower than size's, so it was excluded from the predictive model. No statistically significant differences in terms of survival were identified on the rest of variables considered in the study.

CONCLUSIONS

This study suggests the need for considering age and tumour size as the most relevant clinical variables for predicting survival to oral cancer at the time of diagnosis.

Revision stapedectomy

OBJECTIVE

To evaluate results of revision stapedectomy with and without use of the laser and determine factors predictive of hearing outcome.

STUDY DESIGN AND SETTING

Retrospective review of 356 revision stapedectomy operations performed at the House Ear Clinic, a tertiary neurotologic private practice, between 1983 and 1995.

RESULTS

A postoperative gap of < or =10 dB was obtained in 60% of cases. Results were similar with and without the use of a laser. Sensorineural hearing loss of >10 dB occurred in 7.7%, with 3 (1.4%) ears with profound hearing loss. A poorer outcome was related to incus necrosis, multiple revisions, and indications for surgery other than conductive hearing loss.

CONCLUSION

Revision stapedectomy can provide good gap closure in 60% of cases, with small risk of sensorineural hearing loss.

SIGNIFICANCE

Although not as satisfactory as primary stapedectomy, revision stapedectomy can be offered to patients with reasonable expectations for good gap closure.

Comparison of argon and CO2 laser stapedotomy in primary otosclerosis surgery

PURPOSE

The primary use for the laser in otosclerosis surgery is to create a stapes footplate fenestration that obviates the need for mechanical footplate removal. Experimental studies that evaluate the potential safety of visible (argon and potassium-titanyl-phosphate [KTP]) and invisible (CO2) light laser systems in stapes surgery report conflicting results. The purpose of this study is to compare the clinical safety and efficacy of the CO2 and argon laser systems when used for primary laser stapedotomy.

MATERIALS AND METHODS

A retrospective case review of 124 primary laser stapedotomies using either the argon (n = 59) or CO2 (n = 65) laser was performed. Data consisted of pre- and postoperative air and bone conduction audiometry, speech discrimination scores (SDS), intraoperative findings, and postoperative complications. Between group differences (argon v CO2) were sought using standard statistical methodology.

RESULTS

The argon and CO2 laser groups were comparable with regards to age, sex, preoperative air-bone gap, and laterality. Mean preoperative air and bone conduction pure-tone average (PTA) and SDS were somewhat higher in the CO2 laser group (P < .05). Postoperatively, both groups showed similar results in mean change in air conduction PTA, air-bone gap, and SDS, as well as in the frequency of complications. There were no anacoustic ears in either group.

CONCLUSIONS

The results suggest that the argon and CO2 laser systems are comparable with regards to safety and efficacy when used by experienced surgeons for stapedotomy.

[Histopathology of the internal ear: role of biopsy in ear neurosurgery]

Ultrastructural evaluation is a tool which provides useful information which can lead to understanding of the different physio-pathological mechanisms involved in various otological disorders. After a short review of the procedures presently available for histopathology of human temporal bones from cadavers and indication of their related problem, the authors define the pros and cons of intra-operative biopsies of the membranous structures of the inner ear. The different histopathological methods are presented which may be applied on each specimen along with some technical details which make their use feasible for any otoneurosurgical center. The different membranous inner ear structures are taken into consideration; structures which can be approached by different otoneurosurgical procedures. Emphasis is placed on some technical hints to minimize artifacts. Finally, a more continuous, widespread use of intra-operative biopsies is proposed in order to obtain a fairly large amount of specimens as this would contribute to elucidate the unresolved problems inherent to many otological disorders.

The large vestibular aqueduct syndrome

It has long been known that abnormally large vestibular aqueducts may accompany congenital malformations of the cochlea and semicircular canals. Recently, enlargement of the vestibular aqueducts as the sole radiographically detectable inner ear anomaly has been recognized as a distinct pattern of congenital inner ear malformation. Pathogenesis of the large vestibular aqueduct syndrome probably stems from an early derangement in the embryogenesis of the endolymphatic duct. This anomaly appears to be relatively common in children with sensorineural hearing loss and is probably significantly underdiagnosed. Hearing loss is typically bilateral and progressive, with stepwise rather than fluctuant hearing decrements often triggered by relatively minor head trauma. A review of 17 patients (33 ears) revealed an average hearing level at presentation of 57 dB with a speech discrimination score of 66%. Considerable variability exists in hearing level among affected ears, ranging from normal hearing (4%) to profound deafness (39%). In 12 patients (23 ears) with an average long-term follow-up of 7.3 years, the hearing loss progressed by an average of 25 dB, with a drop of 29% in speech discrimination over the period of observation. An endolymphatic to subarachnoid shunt was performed on seven ears in an effort to stabilize hearing. Four of these ears had a substantial immediate postoperative drop in hearing. For this reason, endolymphatic sac surgery is not recommended for patients with this deformity.

Psychiatric day treatment as alternative to and transition from full-time hospitalization

A review of the comparative studies on day treatment as an alternative modality to traditional full-time hospitalization reveals impressive evidence of its superior effectiveness in facilitating the adjustment and re-integration of patients into the community. On other measures, such as cost effectiveness, family stress, symptom alleviation and relapse rate, day treatment proves to be on par with full-time hospitalization. The data base pertaining to the efficacy of day treatment as a transitional facility from hospital to community is promising, but much too incomplete to permit conclusive statements. Methodological and conceptual issues in the current research are discussed and recommendations for future studies are offered.

Cancer of the extrahepatic bile ducts

Case histories of 47 patients with histologically confirmed carcinoma of extrahepatic bile ducts presenting to M. D. Anderson Hospital and Tumor Institute over a 30-year period were studied. The disease was more common in males during the sixth and seventh decades of life. A third of the patients had history of cholelithiasis. Four patients had prior history of chronic ulcerative colitis and one patient had congenital choledochal cyst prior to development of cancer of the bile duct. Jaundice was the earliest and the most common presenting sign. The tumor was located in the common bile duct more often than in the hepatic ducts. The overall median survival was eight months with two-year and five-year survival rates of 15% and 3%, respectively. The respective values for patients who had resectable tumors were 21.7 months, 57% and 20%. Ascending cholangitis was a frequent complication in patients treated with dilation and intubation and, overall, hepatic failure and systemic infection were more frequent causes of death than distant metastases.