First Report on the Prevalence and Subtype Distribution of Blastocystis sp. in Edible Marine Fish and Marine Mammals: A Large Scale-Study Conducted in Atlantic Northeast and on the Coasts of Northern France

Blastocystis is frequently identified in humans and animal hosts and exhibits a large genetic diversity with the identification of 17 subtypes (STs). Despite its zoonotic potential, its prevalence and ST distribution in edible marine fish and marine mammals remain unknown. A large-scale survey was thus conducted by screening 345 fish caught in Atlantic Northeast and 29 marine mammals stranded on the coasts of northern France for the presence of the parasite using real-time Polymerase Chain Reaction PCR. The prevalence of the parasite was about 3.5% in marine fish. These animals were mostly colonized by poikilotherm-derived isolates not identified in humans and corresponding to potential new STs, indicating that fish are natural hosts of Blastocystis. Marine fishes are also carriers of human STs and represent a likely limited source of zoonotic transmission. 13.8% of the marine mammals tested were colonized and 6 different STs were identified including 3 potential new STs. The risk of zoonotic transmission through marine mammals is insignificant due to the lack of repeated contact with humans. The present survey represents the first data regarding the prevalence and ST distribution of Blastocystis in marine fish and marine mammals and provides new insights into its genetic diversity, host range and transmission.

Preoxygenation and general anesthesia: a review

Because intubation can potentially become a lengthy procedure, the risk of arterial oxygen (O2) desaturation during intubation must be considered. Preoxygenation should be routine, as oxygen reserves are not always sufficient to cover the duration of intubation. Three minutes of spontaneous breathing at FiO2=1 allows denitrogenation with FAO2 close to 95% in patients with normal lung function. Tolerable apnea time, defined as the delay until the SpO2 reaches 90%, can be extended up to almost 10 minutes after 3 minutes of classic preoxygenation. Eight deep breaths within 60 seconds allow a comparable increase in O2 reserves. For effectiveness, the equipment must be adapted and tightly fitted. Inadequate preoxygenation (FeO2 <90% after three minutes tidal volume breathing) is frequently observed. Predictive risk factors for inadequate pre-oxygenation share overlap with criteria predictive of difficult mask ventilation. In cases of respiratory failure, oxygenation can be improved by positive end expiration pressure or by pressure support. In morbidly obese patients, preoxygenation is enhanced in a seated position (25°) and by use of positive pressure ventilation. O2 can also be administered during the intubation procedure; techniques include pharyngeal O2, special oxygen mask, or even pressure support ventilation for patients with spontaneous ventilation or positive pressure ventilation to the facial mask for apneic patients. Clinicians (especially anesthesiologists trained in ENT and traumatology) must be prepared to handle life-threatening emergency situations by alternate methods including trans-tracheal ventilation. The availability of equipment and training are two essential components of adequate preparation.

What are the main "machine dysfunctions" to know?

The incidents related to the medical devices are common during anesthesia and in intensive care unit. These incidents are rarely the cause of complications because monitoring detects them early; alternative scenarios allow bearing these problems. Although the incidence of these complications has much declined, these incidents are serious adverse events and at the origin of life-threatening complications. Improper use of medical devices is the main factor that promotes the onset of these complications. To maintain a high level of security, it is necessary to use and control procedures according to the manufacturer recommendations. This is part of a strategy involving users, biomedical engineers and manufacturers. Several actions are effective in preventing the occurrence of these incidents: the control before use, the continuation of the performance of the equipment, use based on the recommendations of the experts and manufacturers and appropriate training. This strategy is best applied by a clinical expert who has extensive technical knowledge. This expert is a key player for users learning and allows establishing and maintaining rules of use in collaboration with medical staff and biomedical engineers and manufacturers.

Airway fire during tracheostomy

INTRODUCTION

Twenty-five cases of airway fire during tracheostomy have been reported in the literature. The authors describe a case observed in their centre 3 years ago, discuss the causes and preventive management and propose guidelines for prevention of this complication.

CASE REPORT

A 66-year-old woman was intubated and ventilated with 100% oxygen during general anaesthesia for tracheostomy. On opening the trachea by monopolar diathermy, the oxygen present in the endotracheal tube caught fire, inducing combustion of the tube spreading to the lower airways. This airway fire was responsible for severe acute respiratory failure and the formation of multiple laryngotracheal stenoses.

DISCUSSION

Combustion of the endotracheal tube due to ignition of anaesthetic gases induced by the heat generated by diathermy is responsible for airway fire. These various phenomena are discussed. Prevention is based on safety measures and coordination of surgical and anaesthetic teams.

Pressure support ventilation during fibreoptic intubation under propofol anaesthesia †

GOAL OF THE STUDY

To assess the benefit of pressure support ventilation during fibreoptic intubation performed under propofol anaesthesia in patients having an anticipated difficult intubation.

PROCEDURES

Thirty-two patients with ENT cancer, and having at least two criteria for anticipated difficult intubation were prospectively included. All patients received topical lidocaine 2% and propofol by plasma target control infusion (initial target concentration 3 microg ml(-1), then adjusted to maintain loss of consciousness without apnoea). They were randomly assigned between two groups: spontaneous breathing (SB) or pressure support ventilation (with a support level set at 10 cm H(2)O) both using Fi(o(2))=1. Conditions for fibreoptic intubation, respiratory parameters (pulse oxymetry, ventilatory frequency, tidal volume and PetCO2 after intubation) and haemodynamic parameters were recorded.

RESULTS

Patient characteristic data and intubation conditions were similar between both groups. All patients had a successful fibreoptic intubation and none needed a rescue procedure because of desaturation. In spite of a longer duration of intubation, PE'CO2 after intubation was lower and tidal volume during intubation was higher with pressure support ventilation than in SB patients [38.1 (4.2) vs 42.3 (4.7) mm Hg and 371 (139) vs 165 (98) ml, respectively]. Desaturation episodes were observed in two SB patients conversely to no episode during pressure support ventilation, probably because of the higher minute ventilation.

CONCLUSION

Pressure support represents a useful method to improve ventilation during fibreoptic intubation under propofol anaesthesia in patients with an anticipated difficult intubation.

Pressure-controlled ventilation is superior to volume-controlled ventilation with a laryngeal mask airway in children

BACKGROUND

This prospective, randomized, crossover study had two purposes: first, to determine whether pressure-controlled ventilation (PCV) is safer than volume-controlled ventilation (VCV) by preventing gastric insufflation in children ventilated through an laryngeal mask airway (LMA); second, to assess whether the measurement of LMA leak pressure (P(leak)) is useful for preventing leakage during positive pressure ventilation (PPV).

METHODS

Forty-one, 2 to 15-year-old children underwent general anesthesia with an LMA. The expiratory valve was set at 30 cmH(2)O and P(leak) was measured using constant gas flow. Children were randomly ventilated using PCV or VCV for 5 min in order to reach a P(ET)CO(2) not exceeding 45 mm Hg, and then they were ventilated with the alternative mode. If the target P(ET)CO(2) could not be obtained in one mode, we switched to the other. If both modes failed, children were intubated. Tidal volumes, P(ET)CO(2) and airway pressures were noted and compared between modes. Gastric insufflation was checked by epigastric auscultation.

RESULTS

PCV provided more efficient ventilation than VCV, as targeted P(ET)CO(2) was obtained without gastric insufflation using PCV in all cases except one, whereas VCV failed in three cases. No gastric insufflation occurred when ventilating below peak.

CONCLUSIONS

These findings suggest that in the age group studied, PCV is more efficient than VCV for controlled ventilation with a laryngeal mask. Gastric insufflation did not occur with this mode.

Laparoscopic total pelvic exenteration for cervical cancer relapse

BACKGROUND

Laparoscopy classically reduces morbidity and invasiveness. To decrease the operative morbidity associated with exenteration, we considered the possibility of performing a total pelvic exenteration by the laparoscopic approach.

CASE

A 34-year-old woman presented with a cervical cancer relapse. The bladder, uterus, vagina, ovaries, and rectum were mobilized en bloc from the pelvic sidewall. We used vascular endoscopic staplers for the control of sigmoid vessels and anterior branches of internal iliac vessels. The specimen was removed through the vulva. A colo-anal anastomosis and an ileal-loop conduit for urinary tract diversion were made. The operative time was 9 h. The postoperative course was uneventful. Specimen margins were free of disease.

CONCLUSION

With laparoscopic surgical knowledge and new endoscopic staplers, laparoscopic pelvic exenteration procedure is feasible.

[Preoxygenation and upper airway patency control]

During preoperative assessment, risk factors of upper airway obstruction should be evaluated: respiratory insufficiency, low O(2) reserve, preoxygenation failure or difficult face mask ventilation. In healthy subjects, spontaneous breathing O(2) for 3 min is the reference method. Apnoea duration is longer after preoxygenation than after denitrogenation, even if FEO(2) and SpO(2) do not change during the two last minutes of preoxygenation. The apnea time is longer after 3 min spontaneous breathing than after four deep breaths for 1 min in most of the literature. Maximal breathing during 2 min can produce values comparable to those obtained with tidal volume breathing for 3 min. FEO(2) monitoring is helpful in the assessment of preoxygenation quality: In case of oxygenation impairment during anaesthesia induction, algorithm use is helpful. Because desperate emergencies will occur in association with anaesthesia, every location should have the immediate availability of Fastrach and trans tracheal ventilation. Every anaesthesiologist should be familiar with and well practised in a variety of airway management techniques. Teaching programs are organised in order to develop anaesthesiologist sensitisation and skill.

[Survey and budgetary impact of anaesthesia machines failures]

OBJECTIVE

To assess the incidence and the causes of failures of anaesthesia machines in relation to aging. Study design. - Prospective survey from january 1996 to july 2000.

MATERIAL AND METHODS

The causes (mechanical or electronic), the moment of identification (checklist, maintenance operation or quality-control operation) of each anaesthetic machine failure, the repair cost and the maintenance cost of 14 anaesthetic machines have been collected and entered into a database.

RESULTS

Over 31,948 anaesthesia delivered during the period of the study, 614 failures have been declared: 53% were related both to mechanical problems or monitoring failure and 40% were identified during the pre-operative checklist. In half of the cases, a specially trained anaesthetic nurse was able to correct the failure in the operating theatre. The annual rate of anaesthetic machine failure remained stable over the study period and the annual maintenance cost is approximatively 10% of the initial machine value. No procedure was cancelled because of a machine technical failure.

CONCLUSION

Anaesthetic machine failure rate change according to the time should not be criteria for remplacement if rigorous quality control and maintenance operation are used.

Transtracheal high frequency jet ventilation for endoscopic airway surgery: a multicentre study

Serious complications during high frequency jet ventilation (HFJV) are rare and have been documented in animals and in case reports or short series of patients with a difficult airway. We report complications of transtracheal HFFJV in a prospective multicentre study of 643 patients having laryngoscopy or laryngeal laser surgery. A transtracheal catheter could not be inserted in two patients (0.3%). Subcutaneous emphysema (8.4%) was more frequent after multiple tracheal punctures. There were seven pneumothoraces (1%), two after laser damage to the injector, one after difficult laryngoscopy, four with no clear cause. Arterial desaturation of oxygen was more frequent during laser surgery and in overweight patients. Transtracheal ventilation from a ventilator with an automatic cut-off device is a reliable method for experienced users. Control of airway pressure does not prevent a low frequency of pneumothorax.

[Pharmaceutical traceability integrated with the patient file. Development of a computerized hospital application]

The Clinical Pharmacy Department (CPD) of the Gustave Roussy Institute, has developed a traceability software package that is integrated with the patient file. The Traceability & Medical Devices Functional Unit manages the Blood Derivative Medicinal Product traceability circuits, the circuits of over 400 Sterile Medical Devices and, generally speaking, those for all pharmaceutical goods for which traceability is imperative. The SIMBAD-TRACE software package has been developed in situ and was first open for access in March 1999. It enables pharmaceutical traceability data to be accessed from 500 networked workstations. The references tracked generated about 10,000 movements per year. In terms of performance, the system achieves three complementary objectives: 1) reporting traceability scores which reflect the ability of CPD and the establishment to pertinently respond to a complex regulatory requirement on a daily basis; 2) the contribution of the tool to cost containment with respect to allocating rare goods; the contribution of the software package to the implementation of medical device vigilance inquiries, particularly descending inquiries. Finally, SIMBAD-TRACE is one of the pillars of our Quality Assurance Program (QAP).

Mechanisms and risk factors for infection of pulmonary artery catheters and introducer sheaths in cancer patients admitted to an intensive care unit

Pulmonary artery catheters (PACs) are typically inserted for short periods, and the extra-luminal route is assumed to be the overriding source of contamination and/or infection. Our aim was to assess the incidence of PAC and introducer colonization in cancer patients, and to study the mechanisms and risk factors for infection. Patients with a Swan-Ganz catheter admitted to an intensive care unit were prospectively analyzed over 14 months. As soon they were no longer necessary, PACs and introducer sheaths were removed and cultured. We recorded the mean duration of placement, the number of times PACs were handled and the site of insertion. Seventy-nine catheters were inserted in 68 patients. The median (range) duration was three days (0-10) for PACs, and 3.6 days (0-18) for introducers. PAC and/or percutaneous introducer sheath colonization was diagnosed in seven patients (8.9%), but in only one case were both colonized. Colonization rates were 15.5 per 1000 days for PACs and 14.1 per 1000 days for introducers. Introducers were mainly colonized before the 5th day, while PACs were mainly colonized after the 5th day. No PAC or introducer-related local infection or bacteraemia was diagnosed. Colonization was more frequent on catheters inserted into the internal jugular vein. The colonization rate was 5% for PACs and introducers. Our findings suggest that contamination of introducers and PACs may be dissociated and could result from either extraluminal or endoluminal colonization. As three of four PAC colonizations occurred after 5 days, the duration of catheter placement should be considered important. There was little clinical impact of microbial colonization.

Comparison of the intubating laryngeal mask airway with the fiberoptic intubation in anticipated difficult airway management

BACKGROUND

The intubating laryngeal mask airway (ILMA; Fastrach; Laryngeal Mask Company, Henley-on-Thames, UK) may provide an alternative technique to fiberoptic intubation (FIB) to facilitate the management of the anticipated difficult airway. The authors therefore compared the effectiveness of the ILMA with FIB in patients with anticipated difficult intubation.

METHODS

One hundred patients, with at least one difficult intubation criteria (Mallampati class III or IV, thyromental distance < 65 mm, interincisor distance < 35 mm) were enrolled (FIB group, n = 49; ILMA group, n = 51) in this prospective randomized study. Anesthesia was induced with propofol and maintained with alfentanil and propofol after an efficient mask ventilation has been demonstrated. The success of the technique (within three attempts), the number of attempts, duration of the successful attempt, and adverse events (oxygen saturation < 90%, bleeding) were recorded.

RESULTS

The rate of successful tracheal intubation with ILMA was 94% and comparable with FIB (92%). The number of attempts and the time to succeed were not significantly different between groups. In case of failure of the first technique, the alternative technique always succeeded. Failures in FIB group were related to oxygen desaturation (oxygen saturation < 90%) and bleeding, and to previous cervical radiotherapy in the ILMA group. Adverse events occurred significantly more frequently in FIB group than in ILMA group (18 vs. 0%, P < 0.05).

CONCLUSION

The authors obtained a high success rate and comparable duration of tracheal intubation with ILMA and FIB techniques. In patients with previous cervical radiotherapy, the use of ILMA cannot be recommended. Nevertheless, the use of the ILMA was associated with fewer adverse events.

Biting the laryngeal mask: an unusual cause of negative pressure pulmonary edema

PURPOSE

To describe negative pressure pulmonary edema due to biting of the laryngeal mask tube at emergence from general anesthesia.

CLINICAL FEATURES

A healthy patient underwent general anesthesia using a laryngeal mask airway and mechanical ventilation. During recovery, the patient strongly bit the laryngeal mask and made very forceful inspiratory efforts until the mask was removed. Five minutes later, the patient developed dyspnea and had an hemoptysis of 50 ml fresh blood. Chest radiograph showed bilateral alveolar infiltrates. Pharyngo-laryngeal examination was normal. Bronchoscopy revealed no injury but diffuse pink frothy edema fluid. Clinical examination and chest radiograph became normal after 12 hr of nasal oxygen therapy confirming airway obstruction as the most available cause of this pulmonary edema.

CONCLUSION

Airway obstruction due to biting of a laryngeal mask tube may result in negative pressure pulmonary edema.

[The breakdown of anesthesia equipment survey]

OBJECTIVE

To assess the incidence and the causes of failures of anaesthesia machines.

STUDY DESIGN

Prospective survey from August 1995 to September 1997.

MATERIAL

Check-list and machine failure forms.

METHODS

Failures of anaesthetic machines have been collected and entered into a database. Causes and treatment of each failure have been analysed.

RESULTS

Of 5,096 foreseen forms, 3,926 (77%) have been completed after check-list or anaesthesia machine failure. Overall, 233 incidents have been declared (4.5%). Failures identified during the preoperative check-list (n = 96) were mainly related to mechanical problems, especially the gas proportioning device (35%). Perioperative failures (n = 137) were mostly related to electronic problems (ventilator: 27% and monitor: 57%). In more than half of the cases, a specially trained anaesthetic nurse was able to correct the failure in the operating theatre. Using 14 anaesthetic machines for 12 operating rooms, no procedure was cancelled because of a technical failure of a machine.

CONCLUSIONS

This study emphasizes the value of the check-list and the failure report. The presence of a specially trained anaesthetic nurse allows immediate correction of the majority of technical problems.

[Accessory anesthetic breathing systems: verification before use]

Accessory or ancillary anaesthesia breathing systems can be defined as all those connected to the fresh gas outlet of the anaesthetic apparatus and used instead of the circle system associated with the ventilator, which is the main circuit. They include: the Mapleson systems, the systems with a nonrebreathing valve and the disposable systems with a carbon dioxide absorber. They can be a cause of major accidents when not checked before and monitored during use. This technical note describes techniques of preanaesthetic checking and monitoring during anaesthesia.

[Pros and cons of adding an accessory breathing system to the main circle circuit. II. Arguments against their use]

When compared to the circle system alternative breathing systems (ABS) are of no benefit. When the only indication of an ABS is emergency oxygen administration it should be connected to the O2 pipeline upstream from the flowmeter bank and the vaporiser. The use of an ABS for anaesthesia maintenance is no longer justified because of the difficulties in monitoring pressure, flow and concentrations of the gas mixture, the cost of gas and vapour administered at a high flow and the resulting pollution. The use of an ABS for very short anaesthetics is only acceptable if the administered gas mixture is monitored.

[Pressure control in medical gas distribution systems]

OBJECTIVE

To assess whether the pressure gauges at the downstream part of pressure regulators are accurate enough to ensure that pressure in O2 pipeline is always higher than in Air pipeline and that pressure in the latter is higher than pressure in N2O pipeline. A pressure difference of at least 0.4 bar between two medical gas supply systems is recommended to avoid the reflow of either N2O or Air into the O2 pipeline, through a faulty mixer or proportioning device.

STUDY DESIGN

Prospective technical comparative study.

MATERIAL AND METHODS

Readings of 32 Bourdon gauges were compared with data obtained with a calibrated reference transducer. Two sets of measurements were performed at a one month interval.

RESULTS

Pressure differences between Bourdon gauges and reference transducer were 8% (0.28 bar) in average for a theoretical maximal error less than 2.5%. During the first set of measurements, Air pressure was higher than O2 pressure in one place and N2O pressure higher than Air pressure in another. After an increase in the O2 pipeline pressure and careful setting of pressure regulators, this problem was not observed at the second set of measurements.

DISCUSSION

Actual accuracy of Bourdon gauges was not convenient enough to ensure that O2 pressure was always above Air pressure. Regular controls of these pressure gauges are therefore essential. Replacement of the faulty Bourdon gauges by more accurate transducers should be considered. As an alternative, the increase in pressure difference between O2 and Air pipelines to at least 0.6 bar is recommended.

[Quality control of anesthesia equipment after maintenance procedure]

OBJECTIVE

To assess the value of quality control tests after routine maintenance procedures of anaesthesia machines.

STUDY DESIGN

Prospective laboratory study.

MATERIAL AND METHODS

Over a 4-year-period, anaesthesia machines were checked after regular maintenance procedures, in order to detect unrecognized dysfunctions before clinical use.

RESULTS

Overall 106 tests were performed on 14 machines and five dysfunctions were identified. Three of them concerned gas proportioning devices, which delivered a hypoxic gas mixture (FO2 < 15%). This defect was recognized by gas analysis at their outlet, whereas mechanical controls were satisfactory. The last two concerned pressure relief valve linearity and gas leak at PEEP valve.

CONCLUSIONS

This study underlines the necessity of both postmaintenance controls and gas analysis at the outlet of the gas proportioning device. These controls should be performed by hospital technicians, independent from those involved in regular maintenance procedures.

Reconstruction with free jejunal autograft after circumferential pharyngolaryngectomy: eighty-three cases

The free jejunal autograft (FJA) has become a common procedure for pharyngeal reconstruction after circumferential pharyngolaryngectomy. In order to evaluate the postoperative outcome and the functional and carcinologic results, we retrospectively reviewed 83 cases of reconstruction with FJA. Fifty-one patients had received no prior radiotherapy, and 25 had received prior radiotherapy for their hypopharyngeal tumor or for another previous primary. Seven patients underwent a secondary reconstruction. In the postoperative course, there were 2 postoperative deaths, 4 graft failures (5%), and 11 salivary fistulas. The median time to removal of the nasogastric tube was 16 days, and to discharge, 23 days. Forty-eight patients received postoperative radiotherapy, with good tolerance. At 1 year postoperatively, 98% of the patients were able to eat a solid or soft diet. The postoperative radiotherapy did not impair the quality of the functional results in a long-term assessment. The vocal results were disappointing. The 3-year survival rate was 40%. The main carcinologic failures (45 patients) were locoregional recurrences (20 patients) and metastasis, which was the cause of death in 34% of the cases. It seems clear that FJA allows one-stage reconstruction and good swallowing rehabilitation, tolerates postoperative radiotherapy, and increases the quality of life in these patients with a poor prognosis.

Postoperative hypoxaemia: continuous extradural infusion of bupivacaine and morphine vs patient-controlled analgesia with intravenous morphine

We carried out a randomized prospective study in 60 patients who had undergone major abdominal surgery for cancer. For postoperative pain control, 30 patients received continuous extradural infusion of 0.125% bupivacaine 12.5 mg h-1 and morphine 0.25 mg h-1 (EXI group) and 30 received patient-controlled analgesia (PCA) with intravenous morphine (1 mg bolus, 5-min lock-out and maximum dose 20 mg 4h-1). Both groups had general anaesthesia. The two groups were compared for postoperative pain scores, satisfaction, sedation and oxygen saturation. Oxygen saturation was recorded continuously the night before surgery and for two consecutive postoperative nights. Episodes of moderate desaturation (90% > SpO2 85%) were more frequent in the EXI group than in the PCA group (P < 0.05). Pain scores were lower in the EXI group compared with the PCA group at rest and while coughing (P < 0.05). No significant difference was found for patient sedation and satisfaction.

Limits of laryngeal mask airway in patients after cervical or oral radiotherapy

PURPOSE

To test the efficacy of the LMA in patients with previous oral or cervical radiotherapy, without upper airway obstruction.

METHODS

In nine patients after oral or cervical radiotherapy, efficiency of ventilation was assessed after induction of general anaesthesia and LMA insertion. Fibreoptic examination through the tube was performed to check the position of LMA.

RESULTS

In patients who had had oral radiotherapy, all five had limited mouth opening and in two, LMA insertion was difficult but permitted good ventilation. In the four patients who had had cervical radiotherapy, LMA insertion was easy but, in two, the lungs were difficult to ventilate and, in two, the lungs could not be ventilated and orotracheal intubation was required.

CONCLUSION

In patients with limitation of mouth opening after oral radiotherapy, LMA may represent an alternative to tracheal intubation. In patient with cervical sclerosis after radiotherapy; the use of LMA should be avoided.

[Reconstruction with free jejunal graft after total circular pharyngolaryngectomy. 73 cases]

Among the various procedures of pharyngeal reconstruction after circumferential pharyngolaryngectomy, the free jejunal autograft (FJA) has become a common one. We retrospectively reviewed 73 cases of reconstruction with FJA after resection for advanced hypopharyngeal carcinomas (70 primary reconstructions, 3 secondary reconstructions). Postoperative outcome, functional and carcinologic results were studied. There were 1 postoperative death, medical complications in 19 patients, 4 graft failures (5.5%), 11 salivary fistulas. The nasogastric tube was removed before the 15th day in more than a half of the patients. One year postoperatively all the evaluable patients were able to take an oral diet (solid or soft diet for 97% of them). The postoperative radiotherapy was well tolerated. Cancer developed further in 33 patients (13 local and/or nodal recurrences, 13 isolated metastasis, 7 second primaries). The overall survival rate was 44.8% at three years. It seems clear that FJA allows good functional results and increases the quality of life in such patients with poor prognosis.

[Transtracheal jet ventilation with spontaneous ventilation in neoplastic laryngeal dyspnea]

In six suffocating patients with a severe upper airway obstruction (three patients after direct laryngoscopy under general anaesthesia and three patients with cervical tumor scheduled for a difficult tracheostomy), jet-ventilation was delivered using a transtracheal catheter. The jet-ventilator insufflated oxygen only when the tracheal pressure was below a preset value, during spontaneous inspiration. During expiration, tracheal pressure increased above the preset value, the ventilator stopped the insufflation and the expiratory gases escaped through the upper airway. This method corresponds to an inspiratory support without intubation. In post-anaesthesia patients, oxygenation and alveolar ventilation were improved, allowing the avoidance of tracheostomy. In the other patients, tracheostomy was made possible with good surgical conditions under general anaesthesia. This method can be applied in conscious patients and allows oxygenation of suffocating patients.

[A survey of operating and recovery room ventilators and monitoring equipment as well as their maintenance]

OBJECTIVE

To survey the monitoring and anaesthetic devices available in a sample of French hospitals and the modalities of their maintenance.

STUDY DESIGN AND METHOD

Survey carried out in 21 private and public hospitals (including eight university hospitals), affilated to the French Association for Research in Anaesthesia and Intensive Care (ARAR).

RESULTS

More than 84% of all operating theaters were equipped with at least an ECG, a SpO2, and a non invasive blood pressure monitor. The non equipped anaesthesia sites were mainly delivery rooms, plaster cast rooms and X-ray rooms. The figure of recovery room beds was, generally speaking in accordance with the French recommendations. Maintenance policy was not systematic and not budgeted in 72% of the surveyed centres.

CONCLUSION

The equipment in most anesthetic sites has significantly increased, however maintenance policy remains still heterogenous.

Hemodynamic response to induction and intubation. Propofol/fentanyl interaction

BACKGROUND

When given as an intravenous bolus for induction of anesthesia, propofol can decrease postintubation hypertension but can also create moderate to severe postinduction, preintubation hypotension. The addition of fentanyl usually decreases the postintubation hypertension but can increase the propofol-induced preintubation hypotension. The goal of the study was to determine the relation between propofol and fentanyl doses and the hemodynamic changes post-induction, preintubation and postintubation.

METHODS

Twelve groups of 10 patients, ASA physical status 1 or 2, first received fentanyl 0, 2, or 4 micrograms.kg-1 and then 5 min later received propofol 2.0, 2.5, 3.0, or 3.5 mg.kg-1 as an intravenous bolus for induction of anesthesia. Arterial blood pressure was continuously monitored. The trachea was intubated 4 min after propofol administration.

RESULTS

The mean decrease in systolic blood pressure after propofol was 28 mmHg when no fentanyl was given, 53 mmHg after 2 microgram.kg-1 of fentanyl (P < 0.05 vs. no fentanyl), and 50 mmHg after 4 micrograms.kg-1 (P < 0.05 vs. no fentanyl; no statistically significant difference 4 vs. 2 micrograms.kg-1). There was no statistically significant difference in hemodynamic response to intubation relative to propofol dose. Hemodynamic response to intubation was decreased by the administration of fentanyl; the mean increase of systolic blood pressure after intubation was 65 mmHg from preintubation value without fentanyl, 50 mmHg after 2 micrograms.kg-1, and 37 mmHg after 4 micrograms.kg-1 (P < 0.05 for 2 and 4 micrograms.kg-1 vs. no fentanyl and for 4 vs. 2 micrograms.kg-1). Hemodynamic changes postintubation were not statistically different with increasing doses of propofol.

CONCLUSIONS

Hemodynamic changes after induction with propofol or propofol/fentanyl, pre- or postintubation, are not modified when the propofol dose is increased from 2 to 3.5 mg.kg-1. Maximal hypotension preintubation occurs with a fentanyl dose of 2 micrograms.kg-1, whereas the magnitude of postintubation hypertension is significantly decreased with an increase in the fentanyl dose to 4 micrograms.kg-1.

[Use of Diprivan in chronic respiratory insufficiency]

Propofol may be recommended as an anaesthetic agent in patients with chronic respiratory insufficiency since: it prevents the increase in bronchial resistances resulting from the administration of opioids; it possesses a bronchodilator effect, comparable with that of flunitrazepam; it ensures rapid recovery, which would favour patient's co-operation postoperatively. The effects of propofol on respiratory drive should not be neglected, as they may persist even after complete recovery. In pulmonary surgery, propofol may be recommended in patients with one-lung ventilation, since it does not depress the hypoxic vasoconstriction reflex. Some procedures may be carried out in spontaneous ventilation or, preferably, using jet ventilation, provided that propofol is given by means of an infusion pump.

Respiratory mechanics in anaesthetised patients after neostigmine-atropine. A comparison between patients with and without chronic obstructive pulmonary disease

The aim of this study was to compare the effects of pharmacological reversal of neuromuscular blockade on static compliance and resistance in patients with and without chronic obstructive pulmonary disease (COPD). Twenty patients were studied: 12 patients were free of respiratory disease (NCOPD) and had normal pulmonary function tests. Eight subjects (COPD) had a clinical history of chronic bronchitis and a FEV1 < 70% of the predicted value. All patients were anaesthetised with a continuous infusion of methohexitone and alfentanil. Airway pressure (Paw) was recorded continuously. Static compliance (Crs) was calculated from the relationship between 21 syringe volume (250 ml step) and Paw. Total respiratory resistance (Rrs) was measured at two levels of inspiratory flow and tidal volume. These measurements were made before vecuronium (control), after injection of vecuronium to abolish the first neuromuscular response to train of four, 5 and 15 min after administration of neostigmine 40 micrograms.kg-1 and atropine 10 micrograms.kg-1. In COPD patients Crs and Rrs were significantly greater (1450 +/- 580 ml.kPa-1 and 1.06 +/- 0.68 kPa.l-1.s-1) than in normal patients (1000 +/- 380 ml.kPa-1 and 0.58 +/- 0.22 kPa.l-1.s-1) (P < 0.01). In both groups Crs and end-expiratory pulmonary volume were similar before injection of vecuronium and after neostigmine-atropine administration. In both groups, Rrs was not altered significantly by neostigmine-atropine for the two inspiratory flows. These results suggest that neostigmine-atropine mixture is associated with small changes in respiratory mechanics, and the changes are similar in COPD compared with normal patients.

Postoperative pulmonary complications. Epidural analgesia using bupivacaine and opioids versus parenteral opioids

BACKGROUND

Different types of analgesia have been proposed for the prevention of postoperative respiratory complications. The aim of this prospective, double-blind randomized study was to compare the impact of epidural bupivacaine and opioids versus parenteral opioids on respiratory complications in patients who had undergone major abdominal surgery.

METHODS

One hundred fifty-three patients undergoing abdominal surgery for cancer were randomly allocated to receive either general anesthesia with intravenous fentanyl and postoperative analgesia with subcutaneous morphine (SC group) or general anesthesia combined with epidural bupivacaine and epidural bupivacaine plus morphine for postoperative pain relief (EP group). Analgesia was tested on a visual analog pain scale. Pulmonary complications were evaluated according to clinical complications, chest radiographs, arterial blood gas analysis, and pulmonary function tests. The evaluation was carried out on the day before the operation and on the first 5 postoperative days. Particular attention also was paid to the episodes of arterial hypotension and hemoglobin oxygen desaturation during the 1st postoperative night.

RESULTS

Pain relief was significantly better in the EP group than in the SC group (P < 0.05) especially during recovery and on the 1st and 2nd postoperative days. In the EP group, vital capacity decreased less on the 1st postoperative day (P < 0.05) and arterial oxygen tension was greater in the recovery room (P < 0.05). However, no statistically significant difference was observed between the SC and EP groups in the incidence of clinical pulmonary complications (31% and 27%, respectively) and radiographic chest abnormalities (52% and 46%, respectively). The EP group recovered intestinal function earlier (P < 0.05), but significantly more patients in this group had episodes of systolic hypotension (21% vs. 8%; P < 0.05) during the 1st postoperative night. The length of the hospital stay was similar in both groups of treatment.

CONCLUSIONS

Epidural analgesia with a combination of local anesthetic and opioid improves patient comfort. However, this type of analgesia does not decrease the incidence of postoperative pulmonary complications, does not reduce the length of the hospital stay, and carries the risk of complications from episodic systemic hypotension.

Airway obstruction and high-frequency jet ventilation during laryngoscopy

High-frequency jet ventilation has been reported as an effective method of ventilation during laryngoscopy, but may expose the patient to the risks of barotrauma or alveolar hypoventilation. The aim of the study was to evaluate the determining factors of pulmonary complications under high-frequency jet ventilation in 83 patients undergoing laryngoscopy for upper airway cancer. Pulmonary distention was mainly influenced by upper airway obstruction score (p = .0001), while patients with chronic obstructive pulmonary disease (COPD) did not suffer from gas trapping. Impaired gas exchange was predicted by increased weight (p = .0001), smaller injector diameter (p = .02), and lower airway obstruction (p = .001). Hypercapnia occurred in both upper and lower airway obstruction, while hypoxemia was principally observed in COPD patients. Emphasis is placed on monitoring by pulse oximetry, end-expiratory pressure, and PCO2 measurement, especially in patients with obesity, COPD, or upper airway obstruction.

Hemodynamic and catecholamine response to isoflurane versus droperidol in complement to fentanyl anaesthesia

Droperidol (0.03 mg.kg-1 to 0.25 mg.kg-1) with fentanyl has been reported to be less efficient than volatile agents in the prevention of haemodynamic responses to surgery. The aim of this study was to investigate the use of high-dose droperidol in complement to fentanyl in comparison with isoflurane and fentanyl anaesthesia. Thirty patients undergoing laryngectomy were studied. Systolic blood pressure (SBP), heart rate (HR) and plasma catecholamines were analysed both during anaesthesia and during recovery. During surgery, SBP epinephrine (E) levels did not change in either group. HR was slightly lower during droperidol fentanyl anaesthesia. Norepinephrine (NE) levels were significantly higher in the droperidol group than in the isoflurane group (P less than 0.05). During recovery, in both groups, SBP increased by 20% whereas E levels increased by 65%. NE levels increased post-operatively in both groups, but this rise was significantly higher in the droperidol group (P less than 0.01). It is concluded that the two techniques contribute to the haemodynamic stability during surgery, but do not prevent haemodynamic instability during recovery.

Measurement of end-expiratory pressure during transtracheal high frequency jet ventilation for laryngoscopy

An anaesthetic technique using high frequency jet ventilation has been proposed for direct laryngoscopy, but this may expose the patients to the risk of barotrauma. In order to assess this risk, we have measured end-expiratory airway pressure (EEP) through the injector using two three-way solenoid valves mounted in series. At the end of insufflation the first valve was switched off and the apparatus deadspace connected to atmosphere through a large exit port during an adjustable time (decompression time). Then the second valve was switched off and the injection line connected to a transducer, allowing measurement of EEP through the injector. The accuracy of this measurement was tested against airway pressure measured directly in the trachea (Pt) in a lung model. Provided that the decompression time was long enough (70 ms) and the apparatus deadspace was small (6 ml), the difference between EEP and Pt was less than 1 cm H2O for frequencies up to 5 Hz. A clinical evaluation was performed in 64 patients under general anaesthesia before laryngoscopy. EEP correlated with end-expiratory pulmonary volume above apnoeic FRC inferred from abdominal and thoracic displacements. At jet frequencies up to 5 Hz, the correlations between these two variables were satisfactory (r greater than 0.88), suggesting that EEP is a good indicator of pulmonary overdistension.

Pulmonary volume measurements during high-frequency jet ventilation in anesthetized man

To assess the validity of indirect spirometry during conventional intermittent positive-pressure ventilation (IPPV) and high-frequency jet ventilation (HFJV), we measured changes in functional residual capacity (delta FRC) and tidal volume (VT) with two external strain gauges in eight sedated and paralyzed patients. The thoracic and abdominal gauges were calibrated simultaneously in quasi-static and dynamic conditions. The delta FRC measured during HFJV (1 to 5 Hz) and the VT measured during IPPV (0.25 Hz) were found to be equivalent by the two gauges in most patients (r = .90 and r = .99, respectively), but no correlation was found between the VT values inferred by each gauge in HFJV (r = .54). During HFJV, spectral analysis of the gauge signals showed important damping of the abdominal motion (AB) and an amplification of the thoracic displacements (RC) in four patients when measurements were taken at greater than 3 Hz. We conclude that, provided the partition of the volume between AB and RC remains constant, indirect spirometry may measure VT in IPPV and delta FRC in HFJV, but it fails to measure VT accurately during HFJV.

Carbon dioxide monitoring during high frequency jet ventilation for direct laryngoscopy

To improve ventilation monitoring during direct laryngoscopy, we have developed a high frequency jet ventilator which allows the aspiration of tracheal gas for carbon dioxide analysis (PtCO2) through the injector after stopping the ventilator. In 41 patients undergoing direct laryngoscopy, PaCO2 and PtCO2 were measured simultaneously during high frequency jet ventilation under general anaesthesia. PtCO2 and PaCO2 correlated significantly (r = 0.88), but PtCO2 underestimated PaCO2 by 0.84 (SD 0.72) kPa. The arterial to tracheal PCO2 difference was influenced by airway obstruction.

[Evaluation of the risk of pulmonary complications after abdominal surgery]

Pulmonary complications are frequent after abdominal surgery. The object of this study was to evaluate the incidence and the predisposing factors of the postoperative pulmonary complications with a particular attention to their definitions. It included 146 patients. The respiratory complications were separated into clinical complications (bronchitis), radiological complications (atelectasis) and hypoxaemia (PaO2 less than 70 mmHg). Clinical complications (23%) were correlated neither with radiological complications (57%) nor hypoxaemia (46%). They particularly occurred in patients with a preoperative history of respiratory disease. Preoperative risk factors were males, low PaO2 and decreased FEV1. Radiological complications were strongly correlated with postoperative hypoxaemia. Their incidence was not affected by a previous history of respiratory disease. Both radiological complications and hypoxaemia were predicted by age.

Effects of ketamine on isolated human bronchial preparations

The bronchodilator effects of ketamine were examined in human bronchial preparations contracted maximally with histamine, acetylcholine, barium chloride or potassium chloride. Antagonism between ketamine and either histamine or acetylcholine was examined also. Ketamine caused bronchial relaxation irrespective of the constricting agent, and exerted a partial and non-competitive antagonism to histamine and acetylcholine. Propranolol and indomethacin did not inhibit the effect of ketamine, excluding the involvement of beta activation and of prostaglandins.

The influence of position on ventilation-perfusion distribution after abdominal surgery

The effects of a change in position on gas exchange and ventilation perfusion (VA/Q) distribution were studied in 12 patients, after abdominal surgery. VA/Q distribution was determined from retention and excretion curves of six inert gases of different solubilities, in supine and sitting patients, during spontaneous breathing. Changing position from supine to sitting resulted in an increase in minute ventilation and a decrease in PaCO2 without any change in PaO2. With regard to VA/Q distribution, an estimated shunt of 5.2% +/- 3.4 was documented in all the patients in the supine position, and was associated with a large percentage of low VA/Q regions (20.0% +/- 13.0) in six of them. Patients with associated estimated shunt and low VA/Q regions were those with the greatest amount of venous admixture (respectively: 27.3% +/- 7.2, and 14.9% +/- 3.0, for patients without low VA/Q regions, P less than 0.01). When patients were placed in the sitting position, the estimated shunt was not reduced, but the percentage of low VA/Q regions decreased when it was documented. Despite the improvement of VA/Q distribution in the sitting position, the lack of significant change in PaO2 may be explained by the simultaneous decrease in PVO2 caused by a decrease in cardiac output.

Postoperative pulmonary complications: general anesthesia with postoperative parenteral morphine compared with epidural analgesia

In a prospective study, patients undergoing abdominal cancer surgery were randomly allocated to receive either general anesthesia with fentanyl intravenously and postoperative analgesia with parenteral morphine (GA group) or general anesthesia combined with epidural bupivacaine and epidural morphine for postoperative pain relief (EP group). Analgesia was tested on a visual pain scale. Pulmonary complications were evaluated by clinical complications, blood gas analysis, x-ray film changes, and pulmonary volumes (vital capacity, forced expiratory volume in 1 second). Measurements were performed on the day before the operation and on the first 5 postoperative days. In the EP group the pain relief was significantly better on the first day (p less than 0.03). Whatever the criteria used, the rates of pulmonary complications were similar in the two groups: clinical complications 21% versus 26%, radiologic complications 50% versus 64% for GA and EP groups, respectively. Postoperative PaO2 and spirometric values were similar in the two groups. Postoperative epidural analgesia may improve the patient's comfort but does not decrease the incidence of pulmonary complications.

Carbon dioxide clearance during high frequency jet ventilation. Effect of deadspace in a lung model

The effects of the volume and length of deadspace on the clearance of carbon dioxide from a lung model have been investigated during high frequency jet ventilation (HFJV) at 1, 3 and 5 Hz. At 1 Hz, increasing the volume of the deadspace without changing the length caused a reduction in the clearance of carbon dioxide. At 5 Hz, an increase in the length of deadspace decreased carbon dioxide clearance, whilst an increase in volume had no effect. Since the delivered tidal volume was less than the volume of the morphological deadspace at this frequency, the elimination of carbon dioxide must have been accomplished by mechanisms which are not considered important at normal tidal volumes and frequencies. Furthermore, the clearance of carbon dioxide at 5 Hz was very inefficient compared with that at 1 Hz. It is concluded that, during HFJV, carbon dioxide is cleared most efficiently when the frequency is low enough for the delivered tidal volume to be greater than the volume of the morphological deadspace.

Carbon dioxide clearance and deadspace during high frequency jet ventilation. Investigations in the dog

The effects of frequency, tidal volume and added deadspace on carbon dioxide clearance were measured during high frequency jet ventilation at 1, 3 and 5 Hz in dogs. With a short, small volume deadspace, carbon dioxide clearance increased with minute volume at each frequency, but for a given minute volume the clearance decreased with increase in frequency. At 5 Hz, carbon dioxide clearance was less than carbon dioxide production. At 1 Hz, an increase in the volume of added deadspace decreased carbon dioxide clearance, but changes in the length of the deadspace, without change in volume, had no effect. At 5 Hz, an increased volume of added deadspace had little effect on carbon dioxide clearance, but increased length, without change in volume, decreased clearance. Carbon dioxide clearance was increased by placing the jet at the lung end of the tracheostomy tube. It is concluded that at 1 Hz, carbon dioxide elimination is governed by bulk flow, but at 5 Hz other mechanisms are important.

[French survey on anesthesia systems and peroperative respiratory monitoring equipment]

A national inquiry has been carried out in France. It concerned the anaesthetic systems and respiratory monitoring equipment in use at the moment, as well as that wished for. The equipment in use was very stereotyped: an open system with a respirator, for the most volumetric, and with a safety O2/N2O mixer. Monitoring is carried out with the pressure gauges and the measure of expiratory volume; only two thirds of the equipment had an alarm. The O2 and CO2 analysers were little used. Expired CO2 monitoring was only carried out in teaching hospitals and in big centres. Apart from this, the equipment was independent of the hospital and the type of surgery carried out. As for anaesthetic systems, 53% of centres would like obtain open systems, 15% closed systems; 32% did not answer. This increase in number of closed systems is not significant. However, a very strong wish for respirators with flow rate control and safety O2/N2O mixers was observed, whilst the safety parameters of these mixers were open to discussion. Respiratory monitoring was not just confined to the mechanical aspects, as 65% of centres wished to monitor FIO2. The big centres and the teaching hospitals were interested by the expiratory CO2 monitoring. This inquiry showed the interest in respiratory safety in operating theatres. Further studies should confirm or not the increasing interest in closed systems.