CENTRAL VENOUS ACCESS BY AIR MEDICAL PERSONNEL

Daniel P. Davis, MD Prasanthi Ramanujam, MD

ABSTRACT

Background. Vascular access is vital in the resuscitation ofcritically ill and injured patients for both fluid resuscitationand the delivery of medications. However, peripheral accessis not always possible in patients with hypovolemia or dif-ficult anatomy. Central venous access is an alternative vas-cular access strategy for air medical crews, offering the ad-vantage of relatively predictable anatomy, even in unstablepatients. The success and complication rates for the proce-dure in the hands of flight air medical personnel must beconsidered in the decision to institute a central venous accessprocedure. Objective. To explore success and complicationrates for central venous access attempts in patients treatedby air medical crews. Methods. This was a retrospective re-view using advanced procedure quality improvement forms.All air medical patients in whom an attempt at central ve-nous access was made over a 30-month period were included.Femoral and subclavian lines were compared for incidence,success rates, and complications. Results. A total of 50 pa-tients were identified over the 30-month study period. Theincidence of femoral and subclavian attempts was approxi-mately equal. The overall success rate was 66% (60% for sub-clavian, 67% for femoral, and 73% for nonspecified site). Themean number of attempts was 1.2 for each approach. Theonly reported complication was an arterial placement dur-ing a subclavian attempt. Conclusions. We observed mod-erate success rates and a low incidence of reported com-plications with air medical central venous access attempts.Key words: vascular access; air medical crew; resuscitation.

PREHOSPITAL EMERGENCY CARE 2007;11:204–206

BACKGROUND

Vascular access is an essential component of prehospi-tal resuscitation, providing a route for volume resus-citation and medication delivery. Prehospital person-nel are successful in securing peripheral intravenousaccess in approximately 80% of medical patients and90% of trauma patients.1 However, peripheral intra-venous access can be difficult in patients with hypo-

Received February 17, 2006, from the Department of EmergencyMedicine, University of California–San Diego Medical Center, SanDiego, CA (DPD, PR). Revision received July 24, 2006; accepted forpublication September 1, 2006.

Presented at the Poster Presentation, Air Medical Trauma Conference,Austin, TX, October 25, 2005.

Address correspondence and reprint requests to : Daniel P. Davis,MD, UCSD Medical Center and Mercy Air Medical Services,200 West Arbor Drive #8676, San Diego, CA 92103-8676. e-mail:<davismd@cox.net>.

doi: 10.1080/10903120701205232

volemia or difficult anatomy. Central venous cannu-lation is an alternate strategy for advanced prehospi-tal providers. Although in-hospital personnel are gen-erally proficient in establishing central venous access,higher failure rates have been reported under emergentconditions.2,3 In-hospital central venous catheter place-ment is also associated with mechanical, thrombotic,and infective complications.4−9 Common mechanicalcomplications include local hematomas, arterial canu-lation (2%–9%), hemo or pneumothorax (1%–3%), andguide wire-related complications including arrhyth-mias. There are no data on success rates and complica-tions with prehospital attempts at central venous can-nulation. The objective of this study was to describeour experience with air medical central venous access,including success rates and complications with the pro-cedure.

METHOD

Design

We performed a retrospective review covering the timeperiod from January 2003 through June 2005. Waiverof consent was granted by our investigational reviewboard.

Setting

Mercy Air Medical Services includes 12 bases in south-ern California and Nevada. Central venous access usinga subclavian or femoral approach is within the scope ofpractice for flight air medical personnel if peripheralintravenous access cannot be achieved. Internal jugu-lar access is not included because of the high propor-tion of trauma patients, who are typically placed in acervical collar. Flight air medical personnel receive ini-tial and ongoing training in central venous cannulationwith semiannual cadaver laboratories and human pa-tient simulator sessions. They also undergo cognitivereview sessions covering indications, critical procedu-ral steps, and anatomic landmarks.

Subjects

All patients in whom central venous access was at-tempted by air medical crews were included.

Data Analysis

Data were abstracted from the advanced skill form,which is a quality improvement document com-pleted following all attempted procedures. Specific

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Davis and Ramanujam CENTRAL VENOUS ACCESS 205

TABLE 1. Demographic and Clinical Data for All Patients

Parameter (units) Mean or % (95% CI)

DemographicsAge (years) 34 (21–48)Gender (% male) 56

Mechanism of injury/chief complaintMotor vehicle accident (%) 61Other trauma (%) 11Medical (%) 17Drowning (%) 6Burn (%) 6

Vital signsMean SBP (mmHg) 66 (33–99)SBP < 90 mmHg (%) 61Mean pulse rate (beats/min) 103 (78–129)Mean GCS score 7 (4–9)GCS 3–8 (%) 67Use of central line

Rapid sequence intubation (%) 33Resuscitation medications (%) 33Intravenous fluids (%) 83

data included the site of each central venous accessattempt, success of each attempt, total number of at-tempts, and any complications with the procedure.Formal quality improvement mechanisms have beenestablished with all receiving facilities to identify mis-placed catheters and any complications related to cen-tral venous access attempts. These records were alsoreviewed to identify any complications with the pro-cedure, defined as arterial placement, extraluminalpositioning, bleeding, or injury to adjacent structuresincluding pneumothorax. Femoral and subclavian lineswere compared with regard to success rates and compli-cations. Data are presented with 95% confidence inter-vals. Statistical calculations were performed by usingStatsDirectTM (StatsDirect Software Inc., Ashwell, UK).

RESULTS

A total of 50 patients in whom central venous access wasattempted were identified during the 30-month studyperiod (Table 1). This represents approximately one at-tempt per year for each flight air medical personnel.Equal distributions of femoral and subclavian attemptswere observed. The overall success rate was 66%, withno statistically significant difference between femoraland subclavian approaches (Table 2). The mean numberof attempts was 1.2 for both femoral and subclavian ap-

TABLE 2. Number and Success Rate for Attempts by Site

Site n Success % (95% CI)

Subclavian 20 60 (31–81)Femoral 15 67 (38–88)Not specified 15 73 (45–92)Total 50 66 (51–79)

proaches (p = NS). The only reported complication wasa single arterial placement during a single subclavianline attempt. This was not recognized until after admis-sion, likely due to persistent hypotension en route.

DISCUSSION

Establishing intravenous access is important during re-suscitation but can be difficult in cardiac arrest, shock,obesity, and trauma to the neck, torso, or extremi-ties. Air medical crews are able to perform advancedvascular access procedures, including central venouscatheterization, when peripheral intravenous canula-tion attempts are unsuccessful. Here we report our ex-perience with central venous access performed by flightnurses under emergency conditions. Approximatelytwo thirds of patients underwent successful catheterplacement. In addition, a low incidence of complica-tions was reported.

Previous reports regarding central venous canulationreflect in-hospital performance of the procedure, withreported success rates of 80%–85% for subclavian at-tempts among medical house officers and over 90%among experienced physicians,2,3 Most of these datacome from intensive care units, which represent a con-trolled setting. Lower success rates have been reportedunder emergent conditions.3 The success rates reportedhere may reflect suboptimal conditions as well as rel-atively lower experience with the procedure, with anaverage of only one attempted line per flight nurseper year. Reported in-hospital complication rates areapproximately 10% for femoral attempts and 4% forsubclavian attempts.9 We identified only one majorcomplication (2%) during the study period, which in-volved an arterial cannulation with no adverse outcomefrom the event. The low incidence of complications re-ported here may reflect the small sample size or re-porting bias. In addition, previous reports documenta higher incidence of complications with multiple at-tempts (>2), and our relatively low number of attemptsper patient (1.2) may have avoided complications.3,10

Limitations to this analysis include the retrospectivenature of the study as well as the possibility of re-porting bias especially with regard to complications.In addition, there is likely selection bias in the choice ofapproaches, making it difficult to compare femoral andsubclavian attempts. The site was also unspecified in asubstantial number of cases. Furthermore, we did notaddress long-term complications such as thrombosisor infection. Most receiving facilities remove cathetersplaced in the field early after admission, and infection orthrombosis at the site of a previous prehospital centralline attempt may go unreported. Finally, we could notdetermine whether an alternative approach, such as in-traosseous insertion, would have provided equivalentor superior success and complication rates.

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CONCLUSIONS

Here we report modest success rates for air medicalcentral venous access attempts, with a low incidence ofcomplications reported by receiving facilities. The pro-cedure is successful about two thirds of the time, whichis lower than reported for physicians in the hospital. Itis not clear whether these data justify continued use ofair medical central venous access or whether an alter-native, such as intraosseous catheter insertion, shouldbe considered.

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2. Sznajder JI, Zveibil FR, Bitterman H, Weiner P, Bursztein S. Cen-tral vein catheterization: failure and complication rates by threepercutaneous approaches. Arch Intern Med. 1986;146:259–61.

3. Bo-Lin GW, Andersen DJ, Andersen KC, McGoon MD. Percu-taneous central venous catheterization performed by medicalhouse officers: a prospective study. Cathet Cardiovasc Diagn.1982;8:23–9.

4. Rufener JB, Andrews RT, Pfister ME, Hofmann LV, Bloch RD,Kudryk BT, Venbrux AC. An evaluation of commonly em-ployed central venous catheter kits and their potential risk forcomplications of excess guidewire introduction. J Clin Anesth.2003;15(4):250–6.

5. O’Grady NP, Dezfulian C. The femoral site as first choice forcentral venous access? Not so fast. Crit Care Med. 2005;33(1):234–5.

6. Merrer J, De Jonghe B, Golliot F, Lefrant JY, Raffy B, Barre E,Rigaud JP et al. Complications of femoral and subclavian venouscatheterization in critically ill patients: a randomized controlledtrial. JAMA. 2001;286(6):700–7.

7. Deshpande KS, Hatem C, Ulrich HL, Currie BP, Aldrich TK,Bryan-Brown CW, Kvetan V. The incidence of infectious com-plications of central venous catheters at the subclavian, internaljugular, and femoral sites in an intensive care unit population.Crit Care Med. 2005; 33(1):234–5.

8. Domino KB, Bowdle TA, Posner KL, Spitellie PH, Lee LA, CheneyFW. Injuries and liability related to central vascular catheters:a closed claims analysis. Anesthesiology Jun 2004;100(6):1411–8.

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